Tag: NASA

Space Sunday: NASA’s nuclear electric plans, a goodbye to MAVEN and a New Glenn update

Posted on by Inara Pey
A composite image of SR-1 Freedom (rendering) approaching its orbit around Mars. Credit: NASA

Just over a month ago NASA announced plans to test a nuclear propulsion system on  mission to Mars. The news came as a surprise at the time, given it came a year after another nuclear propulsion project involving NASA had joined (along with the US Defense Advanced Research Project Agency (DARPA) had been cancelled.

Called DRACO (Demonstration Rocket for Agile Cislunar Operations), that project was formally initiated in 2021, with the intention of finally evaluating the deep space use of nuclear thermal propulsion (NTP) – that is, the use of a nuclear reactor to heat a propellant mass (usually liquid hydrogen) to generate thrust through the engine nozzles. Targeting a launch date in late 2027, DRACO was always ambitious, and inevitably ran afoul of technical and regulatory challenges starting it on the road to oblivion prior to funding via both DARPA and NASA being halted.

A rendering of the cancelled DRACO DRAPA / NASA nuclear thermal propulsion demonstrator mission. Credit: DARPA

The technological and regulatory problems faced by DRACO primarily concerned two key points. The first being the need for a liquid propellant (requiring substantial propellant mass and the additional mass and complexity of trying to keep the propellant in a liquid state through passive and active means in the full heat of the Sun).

More particularly, DRACO’s nuclear system was to be open cycle, meaning the liquid hydrogen would pass through the reactor system to turn it into the gas needed to propel the vehicle – irradiating it in the process. While people would likely not be too happy about a nuclear reactor spewing radioactive material into the upper atmosphere if it was used whilst in orbit around Earth, the bigger regulatory issue for DRACO was simply how could a system generating radioactive exhaust materials be safely tested on the ground?

Because of this, NASA’s new mission concept – called Space Reactor 1 (SR-1, with the vehicle itself to be called Freedom) instead intends to use nuclear electric propulsion. This is important because it allows the use of a closed cycle nuclear reactor – in this case a closed Brayton cycle fission reactor generating some 50 kW of electrical power. The key point here is that closed cycle reactors can avoid exposing a propellant to radiation, so the exhaust gasses exiting the engine is relatively “clean”. Thus, SR-1 theoretically avoids some of the regulatory issues faced by DRACO.

The “engines” in question for SR-1 are three 12 kW (nominal) Hall-effect thrusters. This in turn is important for a couple of reasons. Firstly, Hall-effect propulsion systems are well understood. Secondly, they utilise a far less volatile propellant than liquid hydrogen  – generally Xenon – which a) doesn’t need to be a liquid form,  and so b) avoids all the complexities of passive and active refrigeration. Both the use of the thrusters and the Xenon fuel therefore cuts out a lot of the technical complexities SR-1 could face when compared to DRACO. Further, SR-1 plans to use a propulsion module that has been in development for some time: the Power and Propulsion Element (PPE) which was to have been used on NASA’s (now cancelled) Lunar Gateway station. This could again help reduce the technical complexities designing SR-1 might otherwise face and it potentially gains political favour in that it offers a means to make good on some of the money already poured into Gateway.

A conceptual image with annotation of the proposed SR-1 Freedom vehicle. Credit: NASA

Nor is SR-1 intended to be a just demonstration of nuclear electric propulsion operating purely in near-Earth  / cislunar space as was the case with DRACO; it is to be a genuine deep-space mission, delivering a payload to Mars in 2029, In doing so it will prove the complete viability of nuclear propulsion in space missions. The payload in question is the Skyfall – and no, it has nothing to do with James Bond!

First revealed as a conceptual study in mid-2025 by NASA’s Jet Propulsion Laboratory (JPL) and AeroVironment, Skyfall is designed to build on the experience gained in flying the Ingenuity helicopter on Mars as a part of the Mars 2020 mission (in which it flew 71 times, often in support of the Mars 2020 rover Perseverance. As initially conceived, Skyfall would utilise six updated versions of the Ingenuity design to carry out a range of scouting flights across Mars. For the purposes of the SR-1 mission, the number of helicopters has been reduced to three – but how they will be delivered into the Martian atmosphere remains dramatic.

When first proposed, Skyfall was to carry six Ingenuity-class helicopter drones to Mars. As a part of the SR-1 mission the number has been scaled back to three. Credit: AeroVironment / NASA

In short, the mission will use a version of the capsule design used to deliver both Perseverance and the Mars Science Laboratory (MSL) rover Curiosity to Mars in 2021 and 2012 respectively. This will protect the three helicopters both on the journey from Earth to Mars and through the heat and buffeting of entry into the Martian atmosphere. After deploying its main parachutes to slow its decent through the atmosphere and jettisoning its heat shield, the capsule will extend a launch platform underneath itself, allowing the three helicopters to power-up their blades and take flight.

Once airborne, the three craft will operate in parallel, carrying out daily low-level flights of Mars, landing to both recharge their batteries and pass the Martian nights. Each will carry a small science package on board, including high-resolution camera to image the terrain they are overflying (to be used in the planning for future missions to Mars) and ground penetrating radar to reveal what lies beneath that terrain, be it rock, permafrost or deposits of water ice.

However, neither Skyfall nor SR-1 are certain to go ahead as planned. Firstly, there is the extremely tight development / test and construction time frame – just 30 months if NASA really is going to achieve a December 2028 / January 2029 launch for the combined mission.

More particularly for SR-1, there are multiple complications still to be overcome. Perhaps the biggest of these is the reactor feedstock: high-assay low-enriched uranium 235 (aka HALEU, with between 5% and 20% enrichment). While this is ideal for use in compact reactors, it requires a dedicated nuclear fuel cycle infrastructure for its production, and this infrastructure is both limited and already at capacity. Whilst the US government is trying to scale HALEU production, this is not going to happen in the short-term. As such, SR-1 could take considerably longer than 30 months to reach a state in which it might reasonably be launched.

Goodnight, MAVEN

On June 3rd, 2026 NASA confirmed their MAVEN (Mars Atmosphere and Volatile EvolutioN) mission had come to an end after a total of 11 years and the orbiter officially classified as lost. The news came some 6 months after all contact with the orbiter was lost and after a long series of attempts to r-establish communications and to understand what might have happened.

Launched in 2013 and commencing its science mission around Mars in 2014, MAVEN was intended to study the Mars atmosphere in an attempt to understand the composition of the upper reaches of that atmosphere and better understand the mechanism at work in stripping away that atmosphere – particularly that of the solar wind. For over 10 years, MAVEN revealed many of Mars’ secrets and the risks human visiting the planet will face (such as solar storms striking the planet quickly doubling surface radiation levels on a temporary basis).

An artist’s impression of NASA MAVEN spacecraft orbiting Mars. Credit: NASA

The first indication that something had gone wrong with MAVEN came on December 4th, 2025, when it failed to resume contact with NASA’s Jet Propulsion Laboratory (JPL) after a routine passage around the far side of Mars. Two days later, JPL received a data fragment from the orbiter, suggesting it was rotating in an unexpected manner and may have deviated from its orbital track. On both December 16th and 20th, 2025, MAVEN passed directly over Gale Crater and the rove Curiosity, but despite the scanning the sky with its high-resolution MastCam along the orbiter’s expected track, there was no sign of MAVEN.

Attempts to regain contact with the orbiter continued at regular intervals throughout early 2026, but by April it was evident that the chances of re-establishing contact were rapidly diminishing. Thus, on By June 3rd, NASA issued a statement terminating the mission while efforts to understand exactly what had gone wrong would continue. Currently, the favoured hypothesis is that MAVEN had an unexpected issue, lost its communications orientation with Earth and was unable to recover. This may have additionally caused the vehicle to drift out of its expected orbit and / or result in its solar arrays being no longer able to generate sufficient power to keep the vehicle’s batteries operating, so it likely ran out of power.

In all, it’s a sad end to a mission that achieved so much, especially given the longevity we’ve come to expect of Mars missions around or on the planet once they have safely entered orbit or landed.

Blue Origin: A Major Malfunction – Update

As per my previous Space Sunday article, on Thursday, May 28th, 2026, a Blue Origin New Glenn booster exploded with tremendous force (estimated to be the equivalent of 1 kiloton of TNT), levelling much of Launch Complex 36 (LC-36) at Canaveral Space Force Base, California, the only facility in the world capable of handling the rocket.

Based on the available images and information available at that time, and as I noted in that article, it seemed that LC-36 would be out of action for at least a year; something that could have major ramifications for Blue Origin and NASA’s Artemis programme. However, June 2nd, 2026, Blue Origin CEO, Dave Limp took to social media with an update on matters which included some surprising news and ended with an even more surprising prediction.

Blue Origin’s launch facilities at LC-36(A) seen in 2025 from the roof of the vehicle and payload integration building, showing a New Glenn rocket atop the transporter-erector vehicle. Credit: Blue Origin

On summary, Limp indicated that:

  • The propellant farm alongside the launch pad weathered the explosion reasonably well and will not require significant rebuilding / replacement (although images have revealed a couple of the tanks do have significant denting).
  • The damage done to the main vehicle and payload integration building appears to far less severe than reports suggested, and the water tower serving the deluge / sound suppression system is largely undamaged.
  • Despite receiving some major damage near its base, the surviving lightning conductor tower can likely be repaired without being demolished – a comment which drew multiple surprised responses given the apparent extent of the damage.
  • Rather than building a new transporter-erector (TE – the 1800-tonne vehicle used to move New Glenn from the vehicle and payload integration building to the launch pad and then act as the rocket’s launch tower), the company will now pivot to a new vertical launch platform / transporter, something they were already planning to do prior to the explosion.

Most surprisingly, however, was Limp’s prediction that Blue Origin will resume New Glenn operations by the end of 2026. Given all that has to be done, both in terms of the rebuilding work at LC-36 (to say nothing as to how long investigations into the vehicle loss will take & what might yet be required to clear New Glenn to resume flights, it is fairly hard to see how this can be achieved. As such, a lot of eyes will be watching Blue Origin and LC-36 very closely over the next 6-7 months.

Space Sunday: postcards from Mars, more HLS news

Posted on by Inara Pey
A September 8th, 2025 Mastcam view looking out over the plains above Jezero Crater, captured by NASA’s Mars 2020 Perseverance rover. The mountains are some 84 kilometres from the rover, with “Lac de Charmes” in between. This a colour-corrected image, adjusted for Earth-level lighting. Credit: NASA-JPL / MSSS

NASA’s Perseverance rover celebrated its fifth anniversary on Mars earlier in 2026 as it continues to explore Jezero Crater and its surroundings. Most recently, the rover has been exploring the western rim of the crater and returning some stunning images. Meanwhile, images and data Europe’s Mars Express orbiter – now into its 23rd year studying Mars – has been used to create more high-resolution images and models of surface features on Mars.

Perseverance has been exploring an area NASA has dubbed “Lac des Charmes” (“Lake of Charms”) after a reservoir serving the Champagne and Burgundy regions of France. In the Martian case, the name has been applied to a paleolake, an ancient lake which no longer exists as such – no water, etc., – but which is still identifiable as a former body of water and which lies on the plains beyond the rim of Jezero Crater.

It’s an especially interesting place to study for several reasons, such as it being home to some of the most ancient rock formations the rover is liable to encounter, including megabreccia – fragments of rock blasted out of Isidis Planitia some 50 km from Jezero by one or more meteorite impacts around 3.9 billion years ago.

A view looking back over the “Arbot” area near “Lac de Charmes”, as captured in 46 images by the Mastcam on Perseverance on April 5th, 2026. The mosaic has been colour adjust for Earth levels of natural light. Credit: NASA-JPL / MSSS

One of the areas imaged by Perseverance showed an area of megabreccia dubbed “Arbot”, which became the subject of study by the rover from April 2026 onwards. The hope of this study is that it might offer some key questions about Mars: the composition of its interior, whether there was a magma ocean on Mars, and what the initial conditions on the planet might have been and whether they might have been conducive to giving life a kick-start.

The exploration of “Lac de Charmes” and “Arbot” brings the total distance driven by the rover to date to just over 42 kilometres. The “selfie” taken at “Arathusa” was also not just for prettiness sake: it allowed mission personnel to see the general condition of the rover, particularly its wheels, helping build confidence that Perseverance is more than capable of continuing its mission for a good time yet as it continues to explore the region above Jezero crater.

Perseverance took this “selfie” on March 11th, 2026, with its Mastcam turned to examine the “Arathusa” rock outcrop. The image is true colour and captured by the MAHLI imager on the rover’s robot arm (which is absent from the image to avoid blocking details, but its shadow can be seen on the ground. Credit: NASA-JPL / MSSS

As NASA was providing updates on Perseverance’s progress, the European Space Agency (ESA) was releasing images recently captured by the High Resolution Stereo Camera (HRSC) aboard the agency’s long-running Mars Express mission as it continues to study Mars.

The images issued by ESA focus on Shalbatana Vallis, a 1,300 kilometre long channel system within the Xanthe Terra region of Mars. It’s not the first time this particular area on Mars has been studied by Mars Express, but these images are among the clearest taken of the valley thus far.

An overhead view towards the northern end of Shalbatana Vallis (to the left) captured by ESA’s Mars Express orbiter. It shows how the valley is a mix of cloaking sand deposited over millions of years, and a still-exposed valley floor. a large channel near the Red Planet’s equator, as seen by the Mars Express orbiter. Credit: ESA / DLR

What makes Shalbatana Vallis of particular interest is the way it is believed to have been formed. On a world where even formations thought to have been formed as a result of liquid water are thought to have done so over hundreds of thousands (or millions) of years, Shalbatana Vallis is thought to have been created in a single, major event which came somewhat later in the planet’s history that its “wet” period.

The theory goes thus: some 3.5 billion years ago, when all liquid water on Mar had either evaporated or vanished underground (eventually becoming permafrost). There was a body of subsurface water under a part of Xanthe which was both heated and kept under pressure by geothermal heating. However, something happened in the region. Perhaps it was a massive Marsquake or perhaps the impact of another meteorite.

Whatever the cause, it resulted in the ground covering the trapped water collapsing it into chaotic terrain and setting the water free in a powerful, tidal wave-like surge. This surge rushed down the prevailing slope of the land towards Chryse Planitia (itself believed to have once been home to a massive body of liquid water), cutting into the soft surface rock to create a broad, deep gouge in its wake.

A stereo view created from the HRSC on Mars Express showing the chaotic floor of Shalbatana Vallis. Note the exposed depositions of dark volcanic dust against one wall of the valley. Credit: ESA / DLR

In the intervening 3.5 billion years since Shalbatana Vallis was carved, the lines of the valley have been softened by dust and sand deposits blown into it by successive Martians winds and seasonal dust storms. However, it has remained the subject of study by both ESA (via Mars Express) and NASA because of the evidence relating to its formation and what it might yet reveal about the ancient past of the planet, hence these images.

The existence of features like Shalbatana Vallis not only provide evidence that Mars was once capable of hosting liquid water on its surface, they also point to the fact that the planet’s history was a lot more varied and complex than simply being a case of formation, hot, wet, cool, dry, cold.

A video made up of images of the Xanthe region and Shalbatana Vallis captured by Mars Express and released in 2025

Psyche’s Mars Fly-by

Mars remains a focus for this article as it briefly had a visitor on Friday, May 15th, 2026, when NASA’s Psyche spacecraft passed around the planet.

Launched in 2023, the 2.6 tonne spacecraft, propelled by solar-powered Hall-effect thrusters, is en-route to study the asteroid 16 Psyche. This is an M-type asteroid roughly 220 kilometres across orbiting the Sun in the asteroid belt between Mars and Jupiter. It is the heaviest such asteroid such discovered – the “M” classification indicating it has a high metallic content. Astronomers believe it could actually be the exposed silicate-iron core of protoplanet, having has its crust and mantle rippled away very early in the history of the solar system and following a collision with another such body. As such, it is hoped that a study of 16 Psyche could reveal more about planetary formation within the solar system.

An artist’s impression of the 2.6 tonne Psyche spacecraft with its 24.7 metre span of solar arrays used to provide electrical power to its systems and Hall-effect thrusters. Credit: NASA

Even with its Hall-effect thrusters, and its massive solar arrays used to capture the Sun’s energy and use it to power the thrusters, NASA’s Psyche spacecraft cannot not reach its destination unaided, hence the fly-by of Mars. This allowed the spacecraft to use Mars’ gravity to give itself both a boost in speed – some 19,848 km/h at the time it approached Mars – and to swing itself onto an orbit inclination and overall trajectory to intercept the orbit of 16 Psyche as it travels around the Sun.

The manoeuvre was completed remotely and successfully, the spacecraft coming to within 4,500 kilometres of Mars. Furthermore, the entire approach to Mars and the fly-by were used to further calibrate the spacecraft’s science instruments – which hopefully included takings pictures of Mars while relatively close to the planet using its stereo imagers.

Psyche is now on the second leg of its journey. It is due to enter an initial orbit around 16 Psyche in July 2029, where it will carry out further instrument calibration tests whilst lowering its orbit to some 700 km over the asteroid. It will then commence the first of four science campaigns, each as a different distances from the asteroid. This first campaign, with the spacecraft in a roughly polar orbit will last for 56 days, imaging and mapping 16 Psyche’s surface from a roughly polar orbit.

A rendering of how 16 Psyche as it might appear to the Psyche spacecraft whilst in orbit around the asteroid. Credit: NASA

In the second campaign, the spacecraft will close to just over 300 km above the asteroid for a further 92 days in roughly polar orbit and examine it in more detail. From here it will translate to a near equatorial orbit around the asteroid at just 75km above its surface, allowing it to study those parts of the asteroid it was unable to image clearly due to lighting issues in the earlier campaign.

The spacecraft will then remain in this low orbit for 100 days before translating back to 190km from 16 Psyche, where it will remain for a further 100 days for the final science campaign. After this, and some 26 months after arriving at the asteroid, the plan is to shutdown the spacecraft as its propellants will be close to expended, and ensure it is safely “parked” orbiting the asteroid.

Blue Origin Delivers Lunar Lander Training Mock-up to NASA

Following my previous piece on the Artemis Human Landing System (HLS) vehicles, NASA and Blue Origin announced the latter has now delivered a full-scale training / study mock-up of the crew module for their Blue Moon Mark 2 (MK2) HLS vehicle.

Blue Origin’s mock-up of the Blue Moon MK2’s crew module as delivered to NASA’s Space Vehicle Mock-up Facility (SVMF) ready for further study and astronaut training. Credit NASA

The unit has been delivered to Johnson’s Space Vehicle Mock-up Facility (SVMF) and lacks the both the engine section that will sit below the crew module and the cryogenic fuel tanks that will sit above on the actual HLS vehicle, as these are not required in a mock-up.

At SVMF, the Blue Moon unit joins mock-ups of space station elements, SpaceX Crew Dragon vehicles and, most relevantly, the Orion spacecraft. It will be used by NASA and Blue Origin to conduct a series of human-in-the-loop tests (testing the design and its systems with human interaction), including mission scenarios, mission control communications, spacesuit checkouts, and preparations for simulated moonwalks. Feedback from the these and simulations will then go back into overall engineering and production decisions affecting the construction of the actual lander vehicles.

An interior shot of the Blue Moon MK2 lander showing the main flight deck area. Credit: NASA / Blue Moon

In all of this, the new unit builds on work initiated using an earlier mock-up located at Blue Origin’s own facilities, together with practical testing of a prototype of the vehicle’s airlock in NASA’s the Neutral Buoyancy Lab in 2025.

Artemis 3: More Details Released

On Wednesday May 13th, 2026, NASA provided further information on the revised Artemis 3 mission currently scheduled for late 2027.

Originally established as the first crewed mission to attempt a return to the lunar surface under the Artemis banner, the mission was re-defined by NASA Administrator Jared Isaacman in February 2026 to be a Earth-orbiting crewed test of one or both of the planned HLS vehicles. Prior to this decision being taken, the only in-space testing of either of the planned HLS vehicles required by NASA would have been uncrewed – hardly ideal.

In the Apollo era, for example, there was crewed testing of the Apollo lunar lander in Earth orbit during the Apollo 9 mission. This allowed astronauts gain hands-on experience in using the vehicle (e.g. piloted control and manoeuvring, ensuring the internal spaces are fit for purpose in zero gravity, etc.) within the environment in which it was designed to operate will before it was flown to the Moon as a part of an actual mission.

The Artemis 3 European Service Module (ESM) mounted on its vehicle adapter and about to undergo acoustic testing in NASA’s Operations and Checkout Facility at Kennedy Space Centre, May 7th, 2026. Credit: NASA / Jess Ruffa

However, other than announcing the use of Artemis 3 for physical testing prior to Artemis 4 and the first planned landing, there has been little further information on how Artemis 3 will work. Some of this detail has now been given, including:

  • The mission duration is to be longer than that of Artemis 2; as well as being used to test one or both of the HLS systems, it will include further tests on Orion’s own systems and capabilities.
  • The Space Launch System (SLS) booster to be used on the mission will not include the upper Interim Cryogenic Propulsion Stage (ICPS), as this is not required in order for the crew-carrying Orion vehicle to reach Earth orbit, where the HLS vehicle(s) are to be tested (it can do this using its European Service Module). Instead, a dummy “spacer” will replace the ICPS.
  • NASA plan to use the mission to also launch additional cubesat missions (as they did with Artemis 2) and is seeking proposal for such missions.

Artemis 3 is set to be one of the most complex mission NASA has yet undertaken, involving potentially  involving the co-ordinated launch of three separate vehicles from three different providers, the on-orbit rendezvous and docking between Orion and up to two different orbiting targets, and the requirement for Orion to move between different orbits in order to do so. As such, there is more to come in terms of the mission and its parameters and goals in the coming months.

Space Sunday: looking at the Artemis HLS vehicles

Posted on by Inara Pey
The Artemis Human landing Systems (aka lunar landers) are being developed by private companies, with Blue Origin developing the Blue Moon Mark 2 HLS (l) and SpaceX the Starship HLS. Credits: (2024) Blue Origin and SpaceX

As is well-known, the US hopes to make a return to the surface of the Moon with astronauts in 2028. This has been, and remains, a questionable time frame for a number of reasons. As I recently reported, NASA’s own Office of Inspector General (OIG) issued a report indicating the new xEVA suits Axiom Space is developing for use on the International Space Station (ISS) and in lunar missions might not be ready for lunar operations until 2031.

Another bump in the road for 2028 is the availability of a vehicle to actually get crews from lunar orbit down to the surface of the Moon and back to orbit again. Again as I’ve oft mentioned, two companies are in the running to supply this vehicle – called the Human Landing System (HLS) in NASA parlance: SpaceX and Blue Origin. The two systems are very different to one another, and each has built-in complexities, some of which are down to NASA’s decision making, others are due to the choices being made by the two companies.

The biggest NASA-defined challenge is that both HLS vehicle must utilise cryogenic propulsion using either liquid oxygen and liquid hydrogen (Blue Origin) or liquid oxygen and liquid methane (SpaceX). The problem here is twofold: mass, and the fact that cryogenic propellants, as the name indicates, require very low temperatures and relatively large volumes in order function, otherwise they will simply (and dangerously) “boil-off”.

The mass of the propellants means that neither HLS system can be launched with the propellant load needed to reach the Moon, enter orbit and then deliver a crew to the surface of the Moon and back to orbit. They have to launched sans propellants and “refuelled” in space. This is turn brings up two issues.

The first is that no-one has ever performed the large-scale (100+ tonnes) transfer of cryogenic propellants in zero gravity (“refuelling” of the International Space Station is commonplace, but uses hypergolic propellants, which are completely different in nature and handling). Thus, both companies must develop and test mechanisms for the transfer of propellants from one vehicle (the “refuelling tanker(s)”) to another, and test then well before 2028 and Artemis 4.

A 2022 concept rendering of two SpaceX Starship vehicles mated back-to-back for cryogenic propellant transfers. Other options under consideration are an engines-to-engines docking for propellant transfer or placing a “fuel depot” in orbit and having the “tanker” missions fill it, before the Starship HLS visits it to take propellants it needs. Credit: SpaceX

The problem of boil-off is potentially more significant. As noted, cryogenics require extremely low temperatures if they are to remain liquid. Should they rise above the required temperatures they will sublimate to gas (boil off), drastically increasing their volume. Thus, if some of this gaseous propellant is not vented from the tanks, it could end up rupturing them completely, destroying the vehicle. Hence why rockets using cryogenics are seen venting clouds of propellants between fuelling and launch.

In space, any vehicle using cryogenics will spend the majority of its time in temperatures of around 121ºC. Even with tank insulation, this means there is likely to be significant boil off, meaning one of three things (or a possible combination of two of them):

  • The Super Heavy booster used in Starship’s 4th integrated flight test (2024) venting boiled-off liquid oxygen from its upper tank and liquid methane from the lower during a propellant load test. Credit: SpaceX

    The excess gases must be vented to space (and the inevitable thrust they cause countered), which in turn will require further propellants to offset such loss prior to the vehicle leaving orbit.

  • Or, the vehicle must include some means of capturing the gas, and refrigerating back down and cycling it back to the tanks – all of which increases vehicle complexity and mass.
  • Or the vehicle must be equipped with some passive means of keeping the propellants as close as possible to their desired liquid temperatures, minimising boil-off, again potentially increasing vehicle mass and complexity.

Thus, both SpaceX and Blue Origin must both find a way of minimising this propellant loss. In the case of SpaceX, this appears to be primarily in the form of loading as much in the way of propellants as possible into the vehicle so that the overall venting does not impact the vehicle’s capabilities; hence the estimates that 8-16 Starship “refuelling” launches might be required for the SpaceX HLS to carry out its mission.

Rather than relying on a massive HLS vehicle with huge propellant tanks, Blue Origin have opted for a much smaller, lighter vehicle (45 tonnes when loaded with propellants compared to the approx. 238 tonnes of the SpaceX HLS when loaded with propellants). However, it needs to be supported by an additional vehicle: Cislunar Transporter.

The latter is a combination of propellant tanks (which will incorporate some form of “zero boil-off” capability Blue Origin has apparently developed) and space-going tug. Following launch, it is designed to be refuelled by a number of New Glenn launches with around 100 tonnes of propellant. It will then dock with the Blue Origin HLS, once launched, and deliver it to lunar orbit, transferring some of its propellants to the lander’s own tanks so it can carry lout its mission.

In addition, and unlike the SpaceX HLS, the Cislunar Transporter will be capable of returning to Earth, where it can be loaded with further propellants and thus service additional flights of the Blue Origin HLS to / from the lunar surface.

A rendering of the Blue Origin Cislunar Transporter in Earth orbit and with its solar arrays for electrical power unfurled. Credit: Blue Origin (2025)

But even with smaller, lower-mass vehicles, Blue Origin faces pretty much the same challenges as SpaceX in terms of propellant loading the storage. So, leaving these issues aside, how is the general development of both systems going and which is likely to get the prestige of returning astronauts to the surface of the Moon first?

On paper, both companies appear to be pretty neck-and-neck in terms of vehicle development. SpaceX for example, has completed around 50 target milestones with its Starship-derived HLS. These include land testing of an airlock test article; the development (with NASA) of an elevator system to be deployed when the vehicle is on the Moon in order to get crews two and from their facilities on the vehicle (roughly 45 metres above the lunar surface) and “ground level”; a “full test” of the life support systems; testing the Raptor engine’s ability to re-light in a wide range of temperature environments; development and testing of the SpaceX-Orion docking system and the vehicle’s avionics, flight and navigation software; mock-ups and testing of pre-launch ground support infrastructure, etc.

Blue Origin has also completed a similar number of tests on both software and hardware, including vacuum testing of the BE-7 engine to be used by their HLS, their cargo lander and the Cislunar Transporter. However, their testing is potentially ahead of SpaceX in some areas, and liable to quickly move ahead in others.

A mock-up of the airlock system to be used on Blue Origin’s HLS vehicle being evaluated by astronauts in the Neutral Buoyancy Laboratory, Johnson Space Centre, 2025. Credit: Blue Origin

For example, where SpaceX has been testing its airlock design on land, Blue Origin has completed testing their airlock system within NASA’s Neutral Buoyancy Laboratory at the Johnson Space Centre. This has allowed space suited astronauts to test the airlock in similar circumstances to those they will experience on the Moon.

As well as this, the company has an integrated, full-scale mock-up of their HLS vehicle. This has allowed Blue Origin and NASA to collaborate directly on the design of the vehicle, including accessibility to critical systems, placement and operation of manual flight control systems, data displays, life-support systems, and the layout of essential crew facilities (toilet, food preparation air, food and beverage storage, personal spaces, etc.), in readiness for the manufacture of the initial HLS craft.

Further, later this year Blue Origin is due to launch the first of its Blue Moon Mark 1 cargo landers to the Moon. Whilst much smaller than the Blue Moon Mark 2 HLS, and only capable of delivering up to 3 tonnes to the Moon’s surface (no “refuelling” required), Blue Moon Mark 1 uses the same automated flight control, space navigation, landing guidance, data communications and propulsion management software as will be used on the Blue Moon Mark 2 HLS. Thus this first Mark 1 mission, featuring the lander Endurance, will be both a practical mission delivering two NASA experiments to the lunar surface and serve as a “pathfinder” test of these automated systems and the capabilities of the BE-7 engine.

If successful, Endurance will be followed in early-to-mid 2027 by a second cargo mission to deliver NASA’s cancelled-then-resurrected VIPER lunar rover mission to the Moon. Assuming either or both of these missions perform as expected throughout, they will pretty much indicate the flight software and BE-7 are fit-for-use within the Blue Moon HLS.

Currently, Endurance is at Blue Origin’s facilities at Kennedy Space Centre, Florida, where it will be integrated with its launch vehicle. Prior to arriving at KSC, Endurance had undergone extensive thermal vacuum chamber testing at NASA’s Johnson Space Centre, exposed the thermal and pressure environments it will face during its mission, and testing its overall readiness to fly.

The commonality of systems is also seen with the Cislunar Transporter. This was originally going to be developed by Lockheed Martin, but is now an in-house project at Blue Origin. This means that as well as utilising the same BE-7 engine, the overall design of the Transporter borrows heavily from the New Glenn upper stage, greatly reducing its development cycle and allowing it to use the Tanks and engine mounts, etc., from the New Glenn upper stage, greatly simplifying its design whilst enabling it to be manufactured on the same production line.

Like Endurance, an initial Cislunar Transporter prototype spent mid-2024 undergoing extensive vacuum and thermal testing at a facility at Edwards Air Force Base, California. As a result, production of the Transporter is due to start at Blue Origin’s primary plant at Kennedy Space Centre.

The SpaceX HLS airlock test article developed for ground-based testing of the system. Credit: SpaceX

It is this progress within Blue Origin, countered by a perceived lack of significant progress by SpaceX on their HLS through 2025, which led NASA’s former Administrator, Sean Duffy to announce the first Artemis crewed landing on the Moon would not be an SpaceX exclusive, but would feature whichever HLS system was fit-for-purpose and ready for a 2028 launch; a decision since confirmed by the current Administrator, Jared Isaacman.

Under Isaacman’s leadership, there is to be a crewed Earth-orbital test of the HLS vehicles in 2027 under the Artemis 3 banner. This test could be with both HLS vehicles, if both are ready in time, or by whichever is available, and will be used in a final determination as to which vehicle Artemis 4 will use.

However, whether Blue Origin or SpaceX will be in position to meet a 2027 HLS test flight is entirely open to debate. Both companies have already asked NASA to push back the test flight from mid-2027 to late 2027, which the agency has done, but Blue Origin remains somewhat tight-lipped about the overall development status of Blue Moon Mk2 and Cislunar Transporter.

Meanwhile, in promising to accelerate its HLS development, SpaceX has set itself some hefty goals for 2026, especially considering we’re fast closing in on being half-way through the year. These include:

  • Actually getting a Starship to orbit.
  • Demonstrating Starship can reach orbit with a “useful payload” – thus far, the “version 1” and “version 2” variants have either sacrificed payload lift capability in favour of just getting to sub-orbital velocity, or sacrificed the ability to achieve orbit in favour of carrying a modest payload – Starlink demonstrators – to sub-orbital velocity. Thus, hopes are now pinned on “version 3”, due to make it s first launch attempt sometime in the next month.
  • Carry out an on-orbit cryogenic refuelling mission.
  • Undertake a “long duration” Starship flight. This was initially defined by the SpaceX CEO as a mission to Mars, now all but abandoned for 2026 (and likely the foreseeable future), leaving the context of the flight uncertain.

There is also the matter of actually recovering Starship vehicles as they return to Earth. This is an essential part of the equation for SpaceX, as the company has indicated it will pay for all of the HLS “refuelling” launches, estimated at up to US $400 million a throw if an entirely new vehicle is used for each if these launches.

Given all that has to be achieved in just 18 months, it may yet ben that the Artemis 3 mission might be further pushed back. If so, then Artemis 4 will likely not occur until 2029 at the earliest (assuming the Axiom xEVA space suits are ready by then). If this happens, then the door to which HLS system is used would again be thrown wide open.

However, there are two additional factors outside of development time frames and general vehicle readiness which could play into Blue Origin’s hands, at least as far as the Artemis 4 mission is concerned: a) vehicle size and mass distribution, b) risk mitigation.

The SpaceX Starship HLS is 52 metres tall and 10 metres in diameter, with a relatively narrow landing leg spread compared to its height. When it comes to landing on the Moon, with the majority of its propellant spent, it also has a very high centre of gravity due to the engines and propulsion systems, crew facilities, power and life support systems, etc., all located in the upper third of the vehicle. Blue Moon Mk2 is only 15.3 metres tall and its centre of mass is in is lower third. It also follows the Apollo lunar lander approach of having a broad spread with its landing legs for increased stability and support.

The Blue Moon HLS lander (l) compared to the Apollo lunar lander (l). Note how the Blue Moon vehicle has a low centre of mass – all major systems and crew facilities at the base, the largely-empty propellant tanks, together with the solar arrays (shown folded) at the top – and a broad set of landing legs similar to Apollo’s to better support it. Credit: Blue Origin

Whilst it is essential all Artemis missions to the Moon minimise the risks faced by their crews, given the “first time” nature of Artemis 4, the use of Blue Origin Mk2 might be seen as the better choice of lander, simply because its squat, low centre of mass design minimises the risk of it toppling over when landing on a unknown surface. The same cannot be said with certainty for the SpaceX design, where even a minor depression directly under one of its landing legs could result in disaster. As such, use of this vehicle might be better suited until after “eyes on the ground” have been able to more accurately determine relatively “safe” areas where it might land.

So, which vehicle do I think will get to fly with Artemis 4? Allowing for the aforementioned caveat of missions being pushed back and assuming SpaceX don’t find a way of testing an uncrewed version of their vehicle to better assess the risk of toppling-on-landing, I do tend to lean towards Blue Origin. While they face challenges – some of them the same as SpaceX, as noted – their approach just comes across as cleaner, more fit-for-purpose. But then, I don’t work for NASA.

Space Sunday: Curiosity’s discoveries and some updates

Posted on by Inara Pey

It’s been a good while since I offered any updates on the work of NASA’s Curiosity rover on Mars, which is a bit of a shame given it was my reporting on Curiosity’s arrival and mission on Mars which eventually morphed into Space Sunday.

Curiosity is now 13 years and eight months into its mission on Mars (over 14 years since its launch from Earth), and it is still going strong. Such is the amount of data still being returned by the rover’s exploration of Gale Crater and, specifically, the great mound of Aeolis Mons at its centre (which NASA unofficially calls “Mount Sharp”), Earth-based review and analysis of its findings is running somewhat behind.

Take two papers on Curiosity’s findings published in April 2026, for example. They relate to data gathered by Curiosity in 2020 and 2022. However, their individual findings both confirm elements of our understanding of Gale Crater’s history and open the door to some intriguing possibilities when it comes to past microbial life on Mars.

The first paper, Diverse organic molecules on Mars revealed by the first SAM TMAH experiment, examines the data gathered by the rover in 2020 whilst examining a rock sample on the slopes of “Mount Sharp” scientists had dubbed “Mary Anning”. This examination revealed the clay-bearing sandstone rock contained no fewer than 21 organic compounds, seven of which had been detected for the first time. Together, they stand as the single largest and most diverse collection of organic compounds to be found in one location on Mars.

To be clear, “organic compounds” should not be taken to mean “evidence of life” – organics can be formed through inorganic processes as well as organic ones. Further, exactly what caused the formation of these compounds in so close proximity to one another is unknown; whilst they could be the result of mineral and chemical interactions with rock, they equally might have been deposited on “Mount Sharp” as a result of a meteorite impact; we just don’t know.

The “Mary Anning” rock, the site of the discovery of more than 20 organic compounds – including seven never previously encountered on Mars. Image via Curiosity’s MastCam. Credit: NASA / JPL

However, what is interesting about these compounds is the fact that they were detected within a surface rock that has been around perhaps for 3.5 billion years, despite the rock being bombarded by solar radiation and subject to wind erosion, etc.. This alone suggests that whilst overwhelmingly hostile to biological processes we’re familiar with, Mars could preserve the biosignatures of any Martian microbes which might have once been present on the planet.

In this regard, the samples gathered and analysed by Curiosity have been shown to contain methyl benzoate. A complex compound often associated with organics (but again can be formed by both organic or inorganic processes); the fact that such a complex ester group compound is present within the rock does strengthen the argument that Mars might yet preserve evidence of past life on Mars.

What’s more – and again with the inorganic / organic caveat – the team behind the paper confirmed the samples taken from “Mary Anning” contains nitrogen heterocycles. These are rings of nitrogen-bearing carbon atoms which here on Earth are considered precursors of RNA and DNA. All of which adds up to a remarking set of findings.

Mapping the Amapari Marker on “Mount Sharp”. Credit: NASA / JPL

The second paper, Amapari Marker Band Metal-Enrichments: Potential Mechanisms and Implications for Surface and Subsurface Water and Weathering in Gale Crater; examines the case for water in Gale Crater using the “bathtub ring” of the Amapari Marker.

The latter is a boundary layer extending for tens of kilometres around the upper reaches of “Mount Sharp” to the point of being visible from orbit using the right equipment. It is believed to form the boundary between the upper limits reached by waters which had formed multiple lakes within the crater during the planet’s warmer, wet periods of its early history, and the upper portion of “Mount Sharp” which was never immersed in water.

Within the Amapari Marker, Curiosity found deposits of compounds and – particularly – metals which were deposited en masse, so to speak, as the waters retreated back down into Gale Crater after reaching this highest point of their extent. Hence the term “bathtub ring”: the Amapari Marker might be thought of as resembling the ring of grime left around the sides of a bathtub once the water has been drained following a particularly mucky bath.

Various views of the Amapari Marker. A-C captured via Curiosity’s MastCam, D-I captured via the MALI imager on the rover’s robotic arm using true colour, monochrome and false colour filters (to highlight deposits in the rocks). Credit: NASA / JPL

Such banding or layer markers are common on Earth as well, and are referred to as redox (REDuction OXidation) reactions. These have been shown to create metals such as iron, zinc, manganese and similar precipitate out of water – which are exactly the irons found in the Amapari Marker in Gale Crater. Thus, not only does this further demonstrate the likeliness that Gale Crater was one home to lakes of considerable depth (“Mount Sharp” is some 5 kilometres high, with the walls of the crater reaching similar heights, allowing for lakes of at least a kilometre or two in depth), it also suggests the potential for the lake to potentially having been inhabitable by Martian microbes.

This is because microbes can mediate redox reactions, and in some cases create thicker deposits than abiotic reactions; deposits that could be even more useful as a source of energy for subsequent colonies of microbes. However, this is, again, only a supposition; there are many questions about the overall conditions within Gale Crater still to be answered. These include matters of Water-to-rock ratios, lake depth, and atmospheric concentrations of O2 during transient events; all make it extremely difficult to draw any single conclusion relating to the lakes in the crater, the deposits found within the Amapari Layer what various combinations of the answers to these questions (if they could be answered) it might mean for the ancient habitability of Mars.

Even so, the findings of these papers again demonstrate how intriguing Mars is.

In Brief

New Glenn Update

In my previous Space Sunday article, I covered the semi-successful Blue Origin NG-3 launch – the third flight of the impressive New Glenn heavy-lift launch vehicle, together with the recovery of the first stage Never Tell Me the Odds as it made its second flight (albeit with new engines). The mission was semi-successful as the upper stage of the booster suffered an anomaly which stranded the BlueBird 7 communications satellite payload in the wrong orbit.

April 19th, 2026: New Glenn NG-3 climbs away from its launch pad at Space Launch complex 36, Canaveral Space Force Station, Florida. Credit: John Raoux

Due to the failure of the upper stage, and as expected, on April 22nd, 2026, the US Federal Aviation Administration (FAA), which oversees commercial launch operations in the US, announced that New Glenn is grounded until a Blue Origin-led investigation can determine the root cause of the issue.

In this, Blue Origin is already a little ahead of the curve: during the NG-3 mission, telemetry indicated that during an initial burn of the upper stage’s engines, one of the two BE-3U motors failed to produce sufficient thrust for the burn to be properly completed, and as a precaution against total vehicle and payload loss, the burn was curtailed and the second required engine burn cancelled, thus leaving BlueBird 7 stranded in the wrong orbit.

The question now is whether the issue with the BE-3U motor is something restricted to that particular motor or something endemic to the entire production of BE-3Us. Determining this, and what – if anything – needs to be done to fix issue, will determine how long New Glenn remains grounded.

An infographic on the BE-4 and BE-3U engines used on New Glenn. credit: Blue Origin

Getting the matter sorted is a priority for Blue Origin. They have four more New Glenn launches planned for 2026. Two of these are commercial (which could slip somewhat easily) and two government-related. One of the latter is a “rideshare” mission of several payloads (NG-7), including a technology demonstrator for the National Reconnaissance Office (NRO). This had been due to launch almost a year ago on a Firefly Alpha rocket, but the NRO opted to move it to another launch vehicle when in April 2025, Firefly suffered its fourth full or partial failure in just seven launches. As such, the NRO might again get nervous if New Glenn is subject to an extended grounding.

More importantly for Blue Origin is the NG-5 launch. This is slated to carry the company’s Blue Moon Pathfinder lander mission to the Moon. Pathfinder, as I’ve noted in past Space Sunday pieces, is a critical demonstration of significant technologies to be used within both Blue Origin’s Blue Moon Mark 1 and Mark 2 cargo / crew lunar landers. As such, any significant delay in its flight could have repercussions for the Blue Moon lander programme as a whole at a time when both Blue Origin and SpaceX are under pressure from NASA to demonstrate they can have human landing systems available to meet the planned Artemis 4 mission of 2028.

NASA: Artemis 3, OIG Concerns and Budget Fight-Back

NASA’s Michoud Assembly Facility in New Orleans, home to the Space Launch System (SLS) production line, rolled out the core stage of the booster that will launch the Artemis 3 mission to Earth orbit in 2027.

Containing the liquid hydrogen tank, liquid oxygen tank, intertank, and forward skirt, the core stage is the bright orange element of the SLS, which at its upper end will be fitted with the stage adaptor for the ICPS upper stage, and at its lower end, the four RS-25 motors that will power the course stage and their housing. Its roll-out at Michoud marks the start of its journey by barge to Kennedy Space Centre, Florida, where it will be integrated with the rest of the 3elements required for the mission, including the Orion Multiple-Purpose Crew Vehicle which will contain the crew for the mission.

The core stage of the SLS rocket destined to launch the Artemis 3 mission is rolled-out from the NASA Michoud Assembly Facility in New Orleans, sans it four RS-25 engines, at the start of its journey to Kennedy Space Centre. Credit: NASA

Artemis 3 was originally going to be the first lunar landing mission for Project Artemis, however, earlier in 2026, the mission was re-targeted as an Earth-orbital test of one or both of the proposed crewed landing craft being developed by Blue Origin and SpaceX, and assess whether either / both are fit for purpose ahead of any lunar-focused missions; as such it is a crucial stepping stone for Artemis.

In this, the roll-out of the new SLS core stage is seen by NASA as a sign that it is on course to meet its current Artemis schedule: orbital HLS testing in 2027 and first crewed landing in 2028. However, the agency’s own Office of Inspector General (OIG) sees things differently.

On April 20th, the OIG – responsible for overseeing all of NASA’s activities in terms of fiscal responsibility, preventing mismanagement, identifying project shortfalls, and generally auditing NASA programmes in terms of their overall progress / readiness – issued a further report indicating that the Artemis programme is once again at risk of delay due to continued issues with the development of the new spacesuits Artemis crews are to use on the surface of the Moon.

An early version of the NASA / Axiom lunar space suit in 2024. This suit has now undergone numerous revisions – including that of colour. Credit: Axiom

Work on the new suits – those currently in use aboard the International Space Station, whilst derived from the Apollo space suits, are unsuitable for lunar use – commenced in the 20-teens and has largely been a source of embarrassment to NASA. Just after the first prototype suit was revealed to the public to much fanfare in 2019, it was found to be unfit for purpose and abandoned.

In 2022, NASA contracted veteran space suit manufacturer Collins LLC (responsible for both the Apollo and ISS space suits) and newcomer Axiom to develop new space suits – but with a twist: the new suits would have to be capable of sustained operations on the lunar surface and also – through the integration of different components / elements during the manufacture of specific suits – for use on the ISS.

Although this sounded reasonable, it actually caused Collins LLC to drop out of the contract in 2024 due to complexities involved in developing such a suit system in a relatively short time frame. Axiom has continued its own suit development, and has offered a number of positive-sounding updates on progress. However, according to the OIG report, the reality with the Axiom suit is somewhat different: it is already running two years behind schedule, in part due to the requirement for the same basic suit having to be adaptable for two very different uses, and now looks likely to slip a further year, meaning it will not be ready for use until 2031.

Both NASA Administrator Jared Isaacman and Axiom offered statements countering the OIG report when it appeared, restating commitments to the 2028 crewed landing. However, the OIG has a track record of being far more accurate in its assessments of the readiness of projects than NASA in meeting target dates for those same projects. As such this report could come back to bite NASA if it proves accurate.

In the meantime, the battle over NASA’s future budget has once more ignited. As I’ve previously reported, in 2025, the Trump Administration sought to reduce NASA’s modest budget by 23% in 2026, including cutting the agency’s science budget by 47%. Ultimately, the House and the Senate rejected such a drastic cut – so the Trump Administration has now simply added the same cuts to its planned 2027 fiscal year budget. In response, the House and Senate – and on both sides of their respective aisles are once again pushing back.

Both the president and Congress have provided explicit direction for NASA to undertake a range of activities, from exploration and science to aeronautics research. We must ensure that NASA is funded at a level that allows it to pursue those missions. I simply do not believe that this budget proposal is capable of supporting what President Trump himself has directed the agency to accomplish over the course of his two terms, nor what Congress has directed by law.

– Rep. Brian Babin (R-Texas), chair man, U.S. House of Representatives’ Committee on Science, Space, and Technology, April 22nd, 2026.

Babin, with the support of Democrats and Republicans on his committee goes on to point out that while American’s spiralling national debt of some US $38.889 trillion or US $116,065 per US citizen (and in a good part fuelled by the fiscal / foreign policies of the current Administration) is of major concern, cutting NASA’s budget amounts to mere “penny-pinching” than it does speak to an attempt to reign-in spending, and is a move that will further damage US leadership in science and technology.

Space Sunday: Artemis 2: around the Moon, home again – and beyond!

Posted on by Inara Pey
We see you: Christina Koch looks out of one of the Orion capsule’s windows towards a GoPro camera mounted on one of the four forward-swept solar array wings of the vehicle’s European Service Module (ESM). To her right, she is holding aloft the mission’s zero-gee indicator / mascot, “Rise”. Created by a 3rd grader, “Rise” has a smiley-faced Moon and is wearing a blue-and-green cap representing Earth, all in a homage to the famous Apollo 8 “Earthrise” photo. Credit: NASA

On Wednesday April 1st, 2026, NASA’s Artemis 2 mission launched on a 10-day cruise to the Moon and back (with time initially spent in Earth orbit), carrying a crew of four to test the capabilities and facilities of the Orion Multi-Purpose Crew Vehicle (MPCV). The mission was a key preparatory step to send crews to the surface of the Moon, starting with the flight of Artemis 4, currently targeting a 2028 launch.

In the first part of this 2-part series I covered Artemis 2 from launch to TLI. Here I complete the voyage in summary form.

Whilst marked by a number of on-going space health experiments, video calls to Earth and performing sundry tasks and s few minor fixes, the outward trip from Earth to the Moon was pretty much a claim affair. A 17.5 second mid-course correction manoeuvre was performed automatically by Integrity, the Orion spacecraft, on mission day 5 – which was actually the first to be performed, the initial correction burn having been cancelled due to Integrity being so precisely on course whilst under its own flight control software.

Taken in high Earth orbit, this image shows the European Service Module and its main engine, with the Earth as a backdrop as the motor is test gimballed ahead of the TLI burn to send Integrity to the Moon. Captured by a solar-panel mounted GoPro camera. Credit: NASA

Day five also saw the crew test their dual-purpose Orion Crew Survival System (OCSS) suits – the orange-coloured space suits the crew wore during the Artemis 2. Designed for quick donning, the suits function as a contingency safety system during the crew’s time aboard and Orion spacecraft, providing up to 144 hours of life support in the event of a cabin depressurisation.

Artemis 2 astronaut Christina Koch poses in her custom-made OCSS suit ahead of the Artemis 2 mission. Credit: NASA.

In their second role, the suits are intended to act as water survival suits in the event of an emergency evacuation of an Orion vehicle post-splashdown. In this role, the suits are intentionally coloured “international orange” so as to be more clearly visible in the water – just like survival suits used on ocean-going cargo vessels, oil rigs, deep sea fishing vessels, etc They additionally have inbuilt flotation devices. Each OCSS is custom made to fit an individual astronaut.

Day five also saw a series of discussions with Mission Control on the upcoming loop around the Moon to review lunar surface targets for observation and photography during the flyby and finalise observation techniques.

On flight day 6, Integrity officially entered the influence of the Moon, with lunar gravity now the dominant force in shaping the vehicle’s trajectory. Until now, Integrity had effectively (if slowly) been decelerating, due to the “pull” of Earth’s gravity behind it, effectively cruising at a few thousand kilometres an hour at it approached the Moon. Now, under the Moon’s influence the craft would start to very slowly accelerate, allowing the Moon’s gravity to swing it around the Moon and lob it back towards Earth without any significant engine burns.

In 1968, the crew of Apollo 8, the first humans to fly around the Moon, captured an iconic image of Earth “rising” over the Moon as the Apollo CSM re-emerged from being on the Moon’s far side. On April 6th, 2026, and 57 years later, the crew of Artemis 2 captured this image of a crescent Earth “setting” over the Moon as their Orion spacecraft started its journey around the Moon’s far side. Credit: NASA

Around the Moon

At 23:00 UCT on April 6th, Artemis 2 made its closest approach to the Moon, passing some 6,545 kilometres above the Moon’s far side. Shortly thereafter Integrity reached a distance of 406,771 kilometres from Earth, breaking the record for the furthest any humans had been from Earth and set by the crew of Apollo 13 in 1970. At this point, Integrity officially started its flight back towards Earth.

During the loop around the Moon, Artemis 2 was in communications black-out with Earth due to the bulk of the Moon being between the spacecraft and Earth, effectively blocking all signals. This blackout lasted 40 minutes, and ended with a successful recovery of comms and telemetry at the expected time.

A gif showing the solar eclipse as seen from deep space by Artemis 2. Credit: NASA

Following the comms blackout, the crew of Artemis 2 witnessed a solar eclipse from deep space as the bulk of the Moon came between them and the Sun. This allowed the crew to observe both the eclipse from a unique perspective, and witness a number of “impact flashes” of meteoroids striking the semi-dark lunar surface facing them. The Moon was not fully dark as the Earth was off to one side relative to Integrity, and so was reflecting sunlight back onto one hemisphere of the Moon, bathing it in “Earthlight”.

Also during the flight around the Moon, the crew christened two previously unnamed craters on the Moon. They named one for their spacecraft, Integrity, whilst the second was – in a poignant moment – named Carroll, in honour of Reid Wiseman’s late wife, who passed away from cancer in 2020.

Artemis 2 crew Commander, Reid Wiseman with his late wife, Carroll, after whom the crew named a crater on the Moon.

Between flight day 7 and flight day 9, Orion departed the Moon’s sphere of influence on its free return trajectory towards Earth, once again slowly accelerating. For most of Day 7 the crew were engaged in debriefing calls with Earth, recording their observations, feelings and emotions during their trip around the Moon whilst memories and reactions were still fresh. They also put in a call to astronauts aboard the International Space Station (ISS).

A further planned use of manual control by Wiseman and Pilot Victor Glover on Day 8 was cancelled in order to allow mission managers conduct a data-gathering exercise related to a non-critical helium leak within the Orion’s European Service Module (ESM), so that they might better analyse the issue post-mission. Two final trajectory adjustment burns were carried out on Days 9 and 10, lasting 8 and 9 seconds respectively. Most of Day 9 saw the crew packing and stowing experiments and equipment in readiness for re-entry and splashdown.

Following the course correction burn on Day 10, the ESM was jettisoned, its work done. The reaction control thrusters system (RCS) on Integrity then operated in sequence over 19-seond period, both manoeuvring the capsule away from the ESM and orienting it in readiness foe atmospheric re-entry.

A gif showing solar panel GoPro camera views of Integrity’s crew capsule sparating from the European Service Module in readiness for re-entry. Credit: NASA

EDS: Entry, Descent and Splashdown

Day 10 saw the most critical elements of the mission unfold: atmospheric entry, descent and splashdown. During Artemis 1, and as I’ve covered in numerous Space Sunday pieces, post-recovery, the heat shield showed some disturbing issues. As well as the expected ablation damage to the heat shield, it also showed signed of deep scoring and charring, with relatively large holes apparently seared through the heat shield material.

After extensive analysis, it was determined that an error in the fabrication process for the initial heat shields for Artemis 1 through 3 had resulted in pockets of gas being trapped in the layers of ablative material. Due to the original re-entry profile for Orion, as used on Artemis 1, which saw the vehicle “skip” in and out of the upper atmosphere to reduce its velocity prior to actual re-entry, these gases ended up being super-heated several times, weakening the heat shield’s structure and eventually blowing holes up and out of it as they outgassed.

While the fabrication process for the heat shields was revised to mitigate any issues of gases becoming trapped – Artemis 2, due to time constraints, would have to fly with its original heat shield. To compensate for this, NASA altered the mission’s re-entry profile to be more Apollo-like: a single direct re-entry. Whilst this might increase stresses on the vehicle and crew, it would reduce the time over which any trapped gases in the heat shield might have expand and contract and weaken its overall integrity, thus increasing the risk of failure.

As it turned out, the heat shield (subject to post-flight inspection) did its job in this new re-entry profile and protected Integrity and its crew, all of which descended by parachute post re-entry to splashdown off the coast of California, where a recovery operation overseen by the USS John P. Murtha out of San Diego saw the recovery of both crew and the space vehicle. Following initial medical checks on the Murtha, the four crew were then flown to the mainland for further check-ups, prior to proceeding on to the Johnson Space Centre in Texas to be reunited with families and loved ones.

The Artemis 2 crew at Johnson Space Centre, April 11th, 2026. (l to r): Jeremy Hansen (CSA); Christina Koch (NASA); Victor Glover (NASA) and a triumphant-looking Reid Wiseman (NASA), holding “Rise” the mission’s zero-gravity indicator and mascot. Credit: NASA

Research related to Artemis 2 will continue post flight, and some of it will continue to focus directly on the four crew, comprising functional check-out tests, simulated space walks, exercises, etc., to further gain insight into the human body’s ability to adapt to low gravity operations and work, and its ability to recover from them. As well as this, all four will be a part of a media circus for some time to come. To them, and all those involved in Artemis and Artemis 2 – congratulations.

What Comes Next?

Originally, Artemis 2 was to be followed by the first attempt at landing an Artemis crew on the Moon. However, this idea both spoke to an unwarranted gung-ho attitude on the part of Artemis management at NASA (no crewed pre-testing of the lunar landing system (called the Human Landing System, or HLS) in Earth orbit), and assumed the mission would actually have a lunar landing vehicle (from SpaceX) available to meet its 2027 launch date.

Blue Origin’s Blue Moon Mark 2 HLS (l) and SpaceX Starship HLS – NOT to scale. The Blue Origin vehicle is 16 metres high as benefits a low centre of mass – crew compartment, engines electronics, etc, all at the base of the vehicle, which includes broad-set landing legs for stability. The SpaceX design – 52 metres tall – suffers from a high centre of mass: crew compartment, electronics, batteries, engines all in the upper third of the vehicle, requiring an elevator (single point of failure) to get crews to / from the surface on the Moon, and a comparatively narrow-set landing legs, further increasing vehicle instability when landing on an unprepared surface like the Moon.

In taking over at NASA, Jared Issacman saw the gung-ho approach of Artemis 3 as a step too far, and so  – with Congressional and White House approval – determined Artemis 3 should be an Earth-orbiting testy of the HLS vehicle by a crew. Also, in keeping with his predecessor, Sean Duffy, he indicated that SpaceX was no longer the sole provider of the Artemis 3 HLS; but would directly face off against Blue Origin, who had been awarded a HLS contract by order of Congress after NASA changed the scope and rules of the original HLS contract to favour SpaceX.

Given that the SpaceX HLS continues to exist as little more than a few disparate elements (such as the crew elevator – largely developed by NASA) and pretty computer renderings, this move to include Blue Origin – who are actively testing elements of their HLS, Called Blue Moon Mark 2 with NASA astronauts – is a wise one, given the SpaceX CEO appears to believe time frames and delivery dates are purely functions of his ego.

A full scale mock-up of the Blue Origin Blue Moon Mark 2 crew section with airlock undergoing testing for astronaut egress / ingress and the recovery of an incapacitated crew member, using the neutral buoyancy facility at NASA’s Johnson Space Centre. Credit: Blue Origin / NASA

As it is, this year should see Blue Origin fly a Blue Moon “pathfinder” mission to the Moon. This will see a scaled-down version of the Blue Moon cargo lander fly a payload from NASA to the Moon, allowing it to test the flight control, navigation, and data communications systems and avionics which will all be part of both the Blue Moon Mark 1 cargo vehicle and Blue Moon Mark 2 HLS. If successful, the mission could put Blue Origin in a strong position to provide the HLS vehicle for both Artemis 4 and Artemis 5.

However, even if one (or both) HLS vehicles get successfully tested in Earth orbit in 2027, it does not mean NASA will be ready to send astronauts to the lunar surface – there is another hurdle to overcome, one entirely of NASA’s own making: cryogenic orbital refuelling.

To explain: while techniques for transferring hypergolic propellants between space  craft has long been available (the ISS, for example, routinely takes on propellants for its manoeuvring thrusters), cryogenic propellant transfer in space is entirely new. It’s not been used before simply because cryogenic propellants are not exactly stable. For one thing, they don’t like heat (and in space, in direct sunlight it s very hot). Heat makes them revert to a gaseous state, expanding their volume. This puts greater and greater pressure on the tanks holding them, such that if the gas isn’t vented to some degree, everything is going to quickly vanish in a brilliant (if silent – in space, no-one can here you go pop!) explosion.

Renderings like this showing one vehicle (in this case a SpaceX Starship (uppermost) transferring propellants to another may look good, but the fact is, such transfers have never been tried in space and are far more complex than hypergolic propellant transfer and storage. Credit: SpaceX

Cryogenic propellants are also heavy in their liquid state, making them somethings of a deadweight if you’re attempting to lift them to orbit rather than burning them as a means to get to orbit. This latter point means that in order just to get to Earth orbit or to the Moon, the SpaceX HLS and Blue Moon Mark 2 (respectively) must launch without the fuel needed to get to the Moon, land a crew and get them back to lunar orbit. Thus, the fuel must be ferried to them post launch.

For Blue Origin, this means launching a Blue Moon HLS to lunar orbit, but without the propellants it needs to operate between lunar orbit and the Moon’s surface. Instead, these must be delivered by a “tanker” craft called the Cislunar Transporter, being developed by Lockheed Martin. But here’s the catch: the Cislunar Transporter has to be launched without the propellants it needs to get to the Moon or those it must transfer to the waiting HLS. So, once in orbit it also has to be “refuelled” by at least two Blue Origin New Glenn rockets.

And if that sounds complicated – SpaceX much do much the same with their HLS, which will launch with only sufficient propellants needed to get to Earth orbit. After this it must either make up to sixteen individual dockings with Starship “tankers” to take on the propellants it needs to reach the Moon and perform its duties there, or it must rendezvous with a (also yet to be built) “orbital fuel depot” previously filled with the propellants it needs by multiple Starship “tanker” flights.

And this is where boil-off comes into play: all of these approaches will result in large volumes of cryogenic propellants spending a lot of time in direct sunlight, turning back to a gaseous state, expanding and requiring venting to prevent their storage tanks rupturing. So techniques and entirely new technologies need to be developed and tested in order to reduce the overall boil-off issues lest more time is spent on “tank top-up” missions than in actually sending humans to the Moon. Further, no-one knows if large volumes of cryogenic propellants can easily be pumped from one vehicle to another in microgravity.

Thus, even though Artemis 2 has been a huge success and NASA is turning its attention to Artemis 3, the programme as a whole still has some hefty hurdles to clear before it is close to being ready to send humans back to the surface of the Moon, and at the current rate of progress, I cannot see all those hurdles being cleared by “early 2028 – less than 2 years from now – when Artemis4 is supposed to launch on its crewed mission to the lunar surface.

Space Sunday: Artemis 2: from launch to TLI

Posted on by Inara Pey
Ignition of the four RS-25 engines on the Artemis 2 SLS, several seconds before the ignition of the two Solid Rocket Boosters (SRBs) seen either side of the SLS core stage, take from a protected camera in the base of the Mobile Launch Platform. Credit: NASA

On Wednesday April 1st, 2026, NASA’s Artemis 2 mission launched on a 10-day cruise to the Moon and back (with time initially spent in Earth orbit), carrying a crew of four to test the capabilities and facilities of the Orion Multi-Purpose Crew Vehicle (MPCV) when used for human spaceflight.

The mission marks a number of firsts for NASA, all critical to future Artemis missions, including:

  • The first launch of a Space Launch system (SLS) rocket with a crew aboard.
  • The first launch of the Orion spacecraft – this one christened Integrity by its crew – with people aboard.
  • The first time an Orion spacecraft has flown under manual control.
  • The first time an Orion vehicle will attempt a re-entry into Earth’s atmosphere carrying a crew aboard.
  • The first time humans have surpassed 400,000 kilometres from Earth.
  • The first time a vehicle intended for use in the vicinity of the Moon has carried an actual toilet on board.
  • The first time a non-US citizen has travelled to the Moon.

The four crew in question are Mission Commander Reid Wiseman, Mission Pilot Victor Glover, Mission specialist Christina Koch (pronounced “Cook”), all from NASA, and Mission Specialist Jeremy Hansen of the Canadian Space Agency. If you’re interested in potted histories of the crew’s backgrounds, then please refer to my previous Space Sunday article.

The four crew of Artemis 2 department the Armstrong Building at Kennedy Space Centre, Florida. (l to r): MS Jeremy Hansen; Pilot Victor Glover; Commander Reid Wiseman; MS Christina Koch. Credit: NASA

Launch

Lift-off came at 22:35 UTC, some 11 minutes later than the target launch time after a couple of minor issues on the SLS vehicle had to be investigated and resolved. One of these related to one of the two battery systems powering the Flight Termination System. The latter is used to destruct the rocket once the crew have been pulled clear by the Launch Abort System (LAS), should a serious issue result in the rocket veering substantially off-course. This particular problem was identified as a sensor failure rather than any fault with the battery itself.

The power of the SLS was immediately apparent following launch – at just thirty seconds into the flight, the launch system has completed its roll to pitch over to the correct ascent angle and was punching through 4.8 kilometres altitude as a speed in excess of 1,920 km/h.  From there:

In just 30 seconds after launch, Artemis 2 was almost 5 kilometres above the Earth and accelerating rapidly. Credit: NASA
  • At T+1 minute the vehicle passed through ”Max Q”, the period when the rocket encounters the peak atmospheric dynamic stresses as it continues to accelerate through the denser portion of the atmosphere, the four RS-25 motors of the core stage throttling back to reduce the load on the rocket.
  • At T+ 90 seconds, with Max Q passed and the RS-25 motors running at 100% thrust, the SLS went supersonic and passing through 22.4 km altitude.
  • At T+2 minutes, with the RS-25 motors had again throttled to 85% thrust, and the two massive solid rocket boosters, their fuel expended, separated to continue on their own ballistic trajectory, eventually falling into the Atlantic Ocean.
  • By 3 minutes into the ascent, Artemis 2 was at 78.4 km altitude, and closing on the 80 km Kármán line, the conventional definition of “the edge of space”. Travelling at some 8,000 km/h, the rocket jettisoned the two fairings that had protected Integrity’s European Service Module (ESM).
  • This was followed almost immediately by the unlocking of the couplings between the LAS at the top of the rocket, and the Orion capsule. The motors on the LAS fired, pulling it clear of the SLS, exposing the Orion capsule to space.
Captured via a film camera mounted on one of NASA observation aircraft, this still shows the SLS rocket of Artemis 2 with its main engines running at full power, together with the separated Solid Rocket Boosters, ESM protective Fairings and the LAS tower, as they part company from the rocket to commence their destructive falls into the Atlantic Ocean. Credit: NASA – Click for full size
  • MECO – main engine cut-off – occurred at 8 minutes 2 seconds after lift-off, with Integrity and the Interim Cryogenic Propulsion Stage (ICPS) continuing to ascend, the reaction control systems (RCS) on the ICPS sufficient to pull it and Integrity clear of the SLS core stage, which, like the SRBs, continued on its own ballistic trajectory, prior to starting a long fall back to Earth, breaking up in the process and falling into the Atlantic Ocean.

At this point, Integrity was travelling at 27,200 km/h – slightly above the speed required to achieve Earth orbit and on a trajectory intended to put it into an elliptical orbit around Earth with a perigee (closest point to Earth) of around 200 km. At this point, operations switched from launch to initial mission activities.

A rear-facing camera on the Orion capsule capture another view of the ESM fairings being separated (centre bottom and (just visible) centre top). Credit: NASA

The latter comprised two major elements: inside the Orion capsule, Christina Koch and Jeremy Hansen left their seats to set-up critical equipment and services. These included unstowing the fire-fighting equipment and mounting it on its assigned racks and then doing the same with the drinking water dispenser, toilet (which had its first malfunction, requiring Koch and Hansen to carry out a fix (the Toilet would again have issues on Flight Day 4, with the crew reporting it was depositing unpleasant odours in the main capsule) and other crew-related equipment. At the same time, Wiseman and Glover remained in their seats and ran through the protocols and check sheets for deploying the ESM’s solar arrays – vital for supplying Integrity with electrical power.

The solar arrays were deployed some 25 minutes after launch, and powered-up to start producing electrical power. At 50 minutes after lift-off, Hansen and Koch were back in their seats, the solar arrays were producing power and the go was given for two orbit-changing manoeuvres.

One of Integrity’s four deployed solar arrays with Earth as a backdrop, as seen from a camera mounted on one of the other solar arrays. Credit: NASA

The first was a short burst of the ICPS RL-10 engine, raising the perigee of Integrity’s orbit whilst maintaining its elliptical form. This was followed by a second 15-minute burn of the RL-10, extending Integrity’s perigee and apogee (the latter to some 70,000 km from Earth, placing the vehicle in a high Earth orbit.

This second RL-10 burn expended almost all remaining fuel in the ICPS, accelerating Integrity almost to the velocity required to complete a trans-lunar injection (TLI) manoeuvre. However, this is not what happened. Instead, with the ICPS separated and orbiting Earth independently of Integrity, Glover and Wiseman commenced what NASA normally refers to as an RPOD simulation, but which for Artemis 2 was simply called “proximity operations”.

RPOD Simulations / Proximity Operations

RPOD – Rendezvous, Proximity Operations and Docking – is a core part of modern day space operations with NASA, being fundamental to crews and supplies being able to launch to and reach the International Space Station (ISS) and then dock safety with it either under automated or manual control.

For the Artemis programme, being able to carry out a successful RPOD is vital to all the lunar surface missions, as they must be able to rendezvous and temporarily dock with the Moon- orbiting Human Landing System (HLS) vehicle which will actually deliver nominated crew members to the surface of the Moon, and then re-dock with the HLS vehicle to allow the surface mission crew return to their Orion craft for a return to Earth.

A conceptual rendering of Integrity performing a simulated RPOD with its ICPS as part of the proximity operations. Thee “docking target” can be seen within the open end of the ESM adaptor fairing. Credit: ESA

To this end, the ICPS had been equipped with a rendezvous and docking target, allowing Wiseman and Glover to test out the docking heads-up display whilst also using Integrity’s RCS thrusters to make simulated rendezvous approaches to the ICPS, aborting before the two vehicles actually made contact. In addition, Wiseman and Glover used manual control of the Orion to test proximity manoeuvring and close formation flying around the ICPS – both the POD and proximity operations marking the first time Orion had ever been manually flown. Both astronauts praised the vehicle’s handling qualities prior to returning the craft to its autopilot.

With Integrity well clear of the ICPS, the latter deployed two CubeSats then fired its RL-10 for a final time, placing it on a destructive re-entry into the upper atmosphere. At this point the crew moved to the next phases of initial operations.

Initial Mission Highlights

First, the Orion’s “gymnasium” – a flywheel device capable of allowing multiple exercises – was set-up and crew members took it in turns exercising, putting Integrity’s life support system through something of a stress test. After this, the crew set-up the food reheater and had dinner together from their rather impressive menu of meal choices. A 4-hour sleep period was then taken, allowing the crew some much needed rest.

Artemis 2 is providing unprecedented coverage, with 2/7 livestreams from the vehicle, frequent mission updates and interviews with the crew – such as this one from Saturday, April 4th, 2026. Form l to r: Reid Wiseman, Jeremy Hansen, Christina Koch and Victor Glover. Credit: NASA / AP

The sleep period was short as a further orbital manoeuvre was required to again raise Integrity’s perigee away from Earth and place it on a trajectory suitable for a TLI burn. With this complete, the crew settled back for another 4-hour sleep period whilst NASA mission control reviewed the overall performance of Orion and its systems to determine if Integrity was good to go for a free-return flight for the Moon.

Authorisation was given for TLI on flight day 2 after the crew had risen and eaten. The manoeuvre comprised a burn of the ESM’s AJ10 main engine of just under 6 minutes, using some 450 kg of hypergolic propellants. It pushed Integrity out of Earth’s orbit and on its way to pass around the Moon. This free return trajectory meant the vehicle would not need to use its AJ10 engine as it passed around the Moon in order to head back to Earth – gravity would do the work for the mission. However, the ESM’s propulsion systems would be required for various mid-course correction manoeuvres.

Captured through a window of the Orion capsule shortly after IPCS separation and with Integrity in a high Earth orbit (HEO), it images shows the night side of Earth, brightly illuminated by sunlight reflected by the Moon. The Sun is on the far side of Earth relative to Integrity, its light causing parts of the atmosphere to glow aurora-like. Credit: Reid Wiseman / NASA

The first of these course corrections was due on Flight Day 3. However, such was the accuracy of the SLS’s performance coupled with that of Integrity itself, this manoeuvre was discarded – the vehicle was precisely on the course it needed. On Flight Day 4 Hansen (a Canadian fighter pilot) and Koch (a jet-qualified civilian pilot) took the controls of Orion and put the vehicle through a further series of RCS tests, evaluating its ability to complete both 3- and 6-degrees of freedom of movement manoeuvres (that is, rolling, pitching and yawing around various axes without altering its general trajectory). Both Koch and Hansen reported the vehicle presented excellent and stable  handling.

Currently, the crew is due to pass around the Moon on Monday, April 6th. 2026 as they do so, they will reach a distance of approximately 406,773 kilometres from Earth, beating the previous record for the furthest humans have travelled from Earth to date – set by the abortive Apollo 13 mission in 1970 – by some 6,000 km. At this point, Integrity will be some 7,600 km beyond the surface of the Moon’s far side as it starts its journey home. The closest Artemis 2 will come to the surface of the Moon is approximately 6,513 km.

Taken on Saturday, April 4th, 2026 through a window on Integrity, this image captures the Moon’s nearside from a distance of around 180,000 km. Credit: NASA (astronaut response for image unnamed).

During the intervening period, the crew continue to test Integrity’s systems and capabilities and carry out a range of experiments, notably related to crew health and welfare. As a part of this work, Integrity carries two key experiments: AVATAR – A Virtual Astronaut Tissue Analogue Response, and an experiment system called ARCHeR (Artemis Research for Crew Health & Readiness (if there is one thing you definitely can say about NASA is that they work very hard at their acronyms!)

AVATAR can mimic individual astronaut organs, allowing medical experts evaluate tissue and other responses to various aspects of spaceflight and monitor essential biomarkers. AVATAR has been flown aboard the ISS several times, but this mission marks its first deep space mission – one that carries it and the Artemis 2 crew through the Van Allen radiation belts – thus offering the opportunity to gain further insight into the potential impact of these highly radioactive zones as Integrity zooms through them at several thousand km/h.

 ARCHeR (which I cannot help think was named by an NASA fan of Star Trek (see Jonathan Archer (Scott Bakula), first commander of the Star Ship Enterprise, NX01) uses movement and sleep monitors worn by the crew to gather real-time health and behavioural information for crew members so scientists can study sleep patterns and overall health performance.

Further, Artemis 2 is testing and demonstrating the Orion Artemis II Optical Communications System (O2O). This is an optical communications system uses laser beams for two-way communications between Earth and the mission. Smaller and lighter than a conventional radio system, O2O also uses less power and increases transmission rates (up to 200 Mbits per second). If successful, O2O could become a feature of future Artemis missions from Artemis 4 onwards and used in potential human missions to Mars.

I’ll have more on Artemis 2 next week. In the meantime, you can follow the mission in real-time, via NASA’s 24/7 livestream.