Space Sunday: Samples from Mars & catching a rocket in mid-air

NASA-ESA Mars Sample Return mission elements: the Mars 2020 rover (l) responsible for collecting / caches samples; the Sample Fetch Rover (2028) responsible for collecting the sample tubes and delivering them to (r) the SRL-1 lander (2028), part of the system for delivering the samples to orbit and the Earth Return Orbiter (MRO – 2027), seen overhead (Earth shown in a piece of artistic licence to illustrate the idea of a sample-return mission). Credit: NASA / ESA

NASA’s Mars 2020 rover Perseverance is busy on Mars carrying out a range of science duties, including gathering samples of sub-surface materials that can be sealed in tubes and returned to Earth by a future Mars Sample Return (MSR) mission.

In all, the rover has 43 such sample tubes, and the plan is for it to “geocache” them at one or two locations on Mars at some point, with one of the caches being used as the target for the MSR mission, which NASA had, until recently, vaguely pointed towards being some time in the 2030s.

However, MSR has been prioritised both by the Decadal Study (see: Space Sunday: Future Mission, SpaceX Update) and US politicians – and as a result NASA and ESA have dusted down plans first proposed in 2018/2019 and revised them for a proposed joint, three-part, six vehicle  mission. This comprises:

  • The Sample Retrieval Lander 1 (SRL1) – carrying the Mars Ascent Vehicle (MAV) – NASA.
  • The Sample Retrieval Lander 2 (SRL 2) – NASA – carrying the Sample Fetch Rover (SFR) – ESA.
  • The Earth Return Orbiter (ERO) – ESA – – carrying the Earth Entry Vehicle (EEV) NASA/ESA.
An early concept of the MSR mission. Credit: NASA/ESA

The mission plan is complicated, but will currently run like this:

2027: The ESA-built ERO vehicle is launched to Mars via an Ariane 6 rocket. It uses ion drive propulsion to cruise to Mars, arriving in 2028, where it will use a separate propulsion system to ease itself into the correct orbit.

2028: SRL-1 and SRL-2 launch to Mars on faster transfer orbits.

  • These both make a soft-landing relatively close to the sample cache.
  • SRL-2 deploys the SFR, which drives to the sample cache and retrieves sample tubes. It then drives the tube to SRL-1.
  • SRL-1 uses a robot arm to transfer the tubes to a capsule at the forward end of the MAV (stowed horizontally on the top of SRL-1 in a protective tube).
  • When ready, the MAV and its protective tube are raised to a vertical position. A spring-loaded “catapult” will then eject the rocket from the tube at a rate of 5 metres per second, allowing the rocket’s motor to safely ignite and power it up to orbit to rendezvous with MRO.
A drawing indicating the major components of the Sample Fetch Rover (SFR). Credit: ESA

The sample return capsule is then transferred from the MAV to a NASA-built containment system contained in the EEV attached to MRO. The latter then engages its ion drive to start it on a gentle transfer flight back to Earth, which it will pass in 2032/33. As it approaches Earth, the EEV is ejected and enters the atmosphere to make a passive descent and landing (no parachutes), using shock absorbing materials to cushion its touch-down in Utah.

Work has already commenced on elements of the mission – such as the Sample Fetch Rover, which ESA is building, and uses design elements  – such as the flexible wheels, the camera systems, etc., – used in the ExoMars Rosalind Franklin rover, and I’ll have more on this joint mission as it develops.

Rocket Lab Grab Their Rocket Out of the Air

Rocket Lab, the New Zealand / US commercial launch company, has recovered one of its launch vehicles after it had successfully sent its payload on its way to orbit. But unlike other companies developing / using re-useable rocket stages, Rocket Lab didn’t land their rocket or let it splashdown – they snatched it out of mid-air with a helicopter!

Rocket Lab’s Sikorsky S-92, trailing the capture line, circles on May 2nd (UTC), awaiting the descent of an Electron rocket first stage under a parachute. Credit: Rocket Lab

The two-stage Electron rocket lifted-off from Rocket Lab’s launch pad on New Zealand’s Mahia Peninsula at 22:49 UTC on May 2nd. The mission, called There and Back Again, was Rocket Lab’s 26th Electron flight, and after sending the upper stage and its payload of 34 smallsats on their way to a successful deployment on orbit, the rocket’s first stage started back to Earth, deploying a parachute to slow its descent.

At just under 2 km above the Pacific Ocean of New Zealand’s coast, Rocket’ Lab’s recovery Sikorsky S-92 made a successful rendezvous the the rocket’s first stage and made an initial capture using a line slung below the helo. Unfortunately, the helo’s crew were forced to release the line within seconds due to the way the booster started to behave after being caught. The rocket then continued one to a splashdown, and was recovered by the Rocket Lab recovery vessel, which was also on station for this eventuality.

Left: the cockpit view as the helicopter approaches the descending Electron first stage. Right: Moments before the capture line initially snags the lines of the rocket’s parachute lines. Credit: Rocket Lab

Whilst not 100% successful, the attempt demonstrated Rocket Lab are on the right track, and likely will be able to capture future Electron stages in mid-air (thus avoiding exposing them to saltwater on splashdown), and fly them back to base for re-use.

In Brief

Virgin Galactic Delays Passenger Sub-Orbital Flights Until 2023

On May 5th, 2022, Virgin Galactic announced it is postponing the start of commercial services with its SpaceShipTwo suborbital spaceplane from late 2022 to early 2023, citing supply chain and labour issues.

Both VSS Unity, the first of the operational Virgin Galactic spaceplanes and the MSS Eve carrier / launch aircraft have been hit by extended delivery times of “high performance metallics” used in some of their components, resulting in a shortage of spares and replacement units.

The first flight of Unity with fare-paying passengers had been expected to take place in the 4th quarter of 2022, but has now been pushed back until the start of 2023, with the end of 2022 now earmarked for final flight tests of both Unity and Eve once the supply chain issues have been resolved, ahead of final certification for commercial flight operations.

Virgin Galactic has pushed back the start of its sub-orbital, fare-paying passenger flights to early 2023

The second sub-orbital vehicle, VSS Imagine, the first f the company’s SpaceShip III class, has yet to complete its own test regime, but is also expected to start passenger flight operations later in 2023. It’s not clear how many vehicle of the class will be built, as the company recently announced it plans to introduce a new “delta class” spaceplane in the mid-2020s.

The company also stated it has now sold 800 tickets for sub-orbital flights that will enable customers to experience around 3 minutes of microgravity. The majority of these were at the “introductory” prices of $250,000, but at least 100 have been at the “full” price of $450,000 – although it is believed most customers have thus far only made the basic down payment of $150,000 a ticket.

ESA Indicate Rosalind Franklin Unlikely to Launch Before 2028

The European Space Agency (ESA) has stated that Rosalind Franklin, the agency’s Mars rover and surface contingent of the ExoMars programme is unlikely not launch until 2028.

As I’ve noted in that past, this rover programme is already around 20 years old, and has had more than its fair share of setbacks. It had been expected to head to Mars later in 2022 using a Russian launch vehicle and lander craft. However, Russia’s invasion of Ukraine put paid to that as all cooperative space activities and projects between Europe and Russia were initially suspended and then scrapped – with ESA noting it has no intention of working in partnership with Russia in the future.

While alternate launch vehicles are available that could get the rover to Mars, the ending of ESA-Roscosmos cooperation means Rosalind Franklin is currently without a lander vehicle and, realistically, one cannot be designed, built and tested in time for launch sooner than the 2028 opportunity (the optimal times to launch missions on a cost-effective basis to Mars using chemical rockets occur once every 26 months).

However, even a 2028 launch is questionable. Firstly, the new lander will require a specific type of rocket motor to slow it during the final stage of landing – and these would have to be supplied by the United States, which will require negotiation and agreement. Secondly, the rover now needs new RHUs (radioisotope heating units) that keep it warm both during the trip to Mars and when on the surface. These were originally supplied by Russia, but have now been withdrawn, so ESA must again turn to the United States for new units. The RHU situation means that ExoMars can only launch from US soil, and this, with the need for the US-built motors likely means the land should be built in the US, all of which needs to be negotiated, so ESA can’t simply go out and build a lander for itself.

Europe’s ExoMars rover Rosalind Franklin – more delays. Credit: ESA

Also, a 2028 launch would mean that the rover would arrive in its designated landing / science location just one month ahead of the annual dust storms that sweep through the region, something to could adversely impact getting the rover checked-out and commissioned after it arrives. A longer flight time could be employed, but orbital mechanics dictate that the rover would be stuck in interplanetary space for two years before arriving at Mars – which is also far from ideal.

Nor is that all. The 2028 launch opportunity has been prioritised for the revised ESA/NASA Mars Sample Return (MSR) mission (see above). As such, there have been suggestions that the entire ExoMars rover could be re-purposed to fulfil the role of the ESA rover in that mission – although it is not clear how this would impact the rover’s current design and its own science goals.

Continue reading “Space Sunday: Samples from Mars & catching a rocket in mid-air”

Space Sunday: future missions, SpaceX update

Decadal Survey 2023-2032. Credit: NASEM

A study outlining priorities in US planetary science for the next decade was published by the United States National Research Council (NRC) on April 19th. Entitled Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032, the report is part of a 20-year history of the NRC offering periodic roadmaps for America’s space exploration strategies, during which time many of the recommendations made have gone on to shape NASA’s activities and goals.

The next decade of planetary science and astrobiology holds tremendous promise. New research will expand our understanding of our solar system’s origins, how planets form and evolve, under what conditions life can survive, and where to find potentially habitable environments in our solar system and beyond.

– from the introduction of the 2023-2032 Decadal Survey

The report – running to 522 pages – includes input from science organisations, universities and research institutions from around the world. Within it, the committee has identified twelve priority science questions that should be the focus of NASA and America’s work in space. These are divided into three categories: Origins, Worlds and Processes, and Life & Habitability, with each category including a total of 12 major areas of investigation, with the committee outlining the robotic and crewed mission proposals that NASA should consider undertaking in support of these investigations.

This report sets out an ambitious but practicable vision for advancing the frontiers of planetary science, astrobiology, and planetary defence in the next decade. This recommended portfolio of missions, high-priority research activities, and technology development will produce transformative advances in human knowledge and understanding about the origin and evolution of the solar system, and of life and the habitability of other bodies beyond Earth

– from the 2023-2032 the Decadal Survey

Highlights of the survey’s recommendations include:

Flagship Missions

Flagship missions are the “big ticket” missions for NASA. At the time of the last Decadal Survey (2011), the flagship missions were identified at the Mars 2020 mission, Europa Clipper, and the Uranus Orbiter and Probe (UOP) – the latter ultimately losing out to the other two.

This being the case, UOP has been awarded the highest priority within the 2023-32 survey. It would deliver an in-situ atmospheric probe into Uranus’ atmosphere and conduct a multi-year orbital tour to study the ice giant and its system of moons, with the objectives including the study of Uranus’ interior, atmosphere, magnetosphere, satellites, and rings.

A drawing of the proposed Uranus Orbiter and Probe.

Due to the need to utilise planetary fly-bys (gravity assists) to reach its destination, UOP would not launch until the early 2030s, when planetary alignments would facilitate the needed assists, with the primary science mission around Uranus commencing in the mid-2040s.

A second Flagship mission identified by the survey as worthy of consideration by NASA is the Enceladus Orbilander. If funded, this mission would launch in the late 2030’s sending a compact robot vehicle to orbit Saturn’s icy moon of Enceladus, passing through the plumes of water we know to be escaping the moon’s subsurface ocean as a result of gravitational interactions with Saturn. The aim of the mission is to to sample and study the plumes before making a landing on Enceladus in the early 2050s to search for biosignatures either in the surface ice.

New Frontier Missions

Regarded as “medium priority” missions, the New Frontier missions identified in the survey for further / continued development are designed to increase our understanding of the major and minor bodies in the solar system. The cost of such missions is capped at US $1.65 billion, with NASA likely to select two new missions from the crop of recommendations. They comprise:

  • Europa Clipper: a former Flagship mission, now downgraded to reflect its advanced status, this is due for launch in October 2024. It will arrive in orbit around Jupiter where it will fly by Europa multiple times, investigating the moon’s habitability and help identify a potential landing site for a future Europa Lander mission.
  • A Ceres sample / return mission to follow-up on the Dawn mission’s orbital survey of the asteroid Ceres.
  • A comet sample return mission.
  • A network of lunar landers to collect geophysical data.
  • A Saturn orbiter mission to follow-up on the Cassini mission.
  • The Oceanus Titan orbiter, proposed but not selected as a 2017 Frontiers Mission.
  • A Venus “in situ atmospheric” mission – possibly a vehicle to deliver a balloon that would drift through the upper reaches of Venus’ atmosphere.
  • A Triton (Saturn’s largest moon) orbital mission.

Mars Exploration

For the first time, a Decadal Survey identifies Mars as a dedicated target for exploration, specifically  underling two missions:

  • The long-planned Mars Sample Return mission, which has had its share of ups and downs, and has yet to be properly settled upon by NASA.
  • The yet-to-be-defined Mars Life Explorer (MLE) mission designed to look specifically for signs of current microbial life on Mars and to pave the way for future human missions to Mars.
[A] sample return will provide geologic materials that are not represented among Martian meteorites and whose volatile, organic, and secondary mineral composition have not been altered by impact… In addition, sample return will allow for future analyses by instruments and techniques not yet developed. As has been the case with the Apollo samples from the Moon, future analyses are expected to yield profound results for many decades after sample return.

– from the 2023-2032 the Decadal Survey

The survey calls for cohesion between robotic and human missions is a priority for future missions to the Moon and Mars. Credit: NASEM

Lunar and Human Exploration

Unsurprisingly, the survey supports NASA’s lunar ambitions, identifying the need for robotic missions in support of a human presence on the Moon, the establishment of an “Artemis Basecamp” in the south polar region of the Moon. This also recommends much more coordination for human activities on the Moon to be linked with human missions to Mars.

Planetary Defence

A call for the development and improvement of our abilities to detect and track near-Earth Objects (NEOs) that may come to pose an impact threat for Earth, and the means to mitigate such genuine threats when identified and confirmed.

The highest priority planetary defence demonstration mission to follow DART and NEO Surveyor should be a rapid-response, flyby reconnaissance mission targeted to a challenging NEO, representative of the population of objects posing the highest probability of a destructive Earth impact (~50-to-100 m in diameter). Such a mission should assess the capabilities and limitations of flyby characterization methods to better prepare for a short-warning-time NEO threat.

– from the 2023-2032 the Decadal Survey

Which of the missions outlined by the survey are actually adopted will be down to a combination of NASA planning and congressional funding / willingness to support the goals and aspirations set out throughout the report.

Picture of the Week

Paris, April 17th 2022: the full Moon rises in line with the Arc de Triomphe and the Avenue des Champs-Elysées – a single exposure image captured by astro-photographer Thierry Legault. No compositing or other post-process used. Credit: Thierry Legault

SpaceX Starship Update

SpaceX has been moving ahead rapidly with the development of both prototypes of their Starship / Super Heavy vehicles and the facilities required to manufacture and launch them.  Here’s a quick summary of key activities since my last update:

  • Booster 7 (sans any Raptor 2 engines) has undergone initial cryogenic and pressure testing whilst on both the orbital launch platform and the “Can Crusher”.
  • The test on the launch stand marked the first time any Super Heavy booster has had both tanks filled with cryogenic liquid (in this case, liquid nitrogen).
  • The tests on the “Can Crusher” have comprised both an ambient nitrogen pressure test of the tanks under high gaseous pressures and liquid nitrogen load tests.
  • The load tests have apparently included the use of the thrust rams of the “Can Crusher”, designed to simulate the pressure exerted against the rocket as a result of the thrust from its Raptor 2 motors.
Booster 7 undergoing cryogenic testing using liquid nitrogen to fill both tanks to capacity, forming frost on the outside of the stainless steel hull. Credit: NASA Spaceflight.com

At the same time as this work has been carried out, work on the next Super Heavy rocket – Booster 8 – appears to have been accelerated.

  • This has led to a degree of speculation that Booster 8 will actually make the first orbital launch attempt, not booster 7, which may be consigned to the role of a structural test article (much like Booster 1 and Booster 4).
  • The reason for this thinking is that Elon Musk has stated that with Raptor 2 production still ramping up, there will only be sufficient engines for a single booster by May, when SpaceX hope to complete the first orbital launch test. So if these engines are to be used on Booster 7, there seems little need to accelerate the assembly of Booster 8.

It also now seems likely that Starship 24 will be the vehicle to participate in the orbital launch attempt with either Booster 7 or 8. Originally, the inclusion of a payload bay door to facilitate the deployment of Starlink satellites, had been thought of as indicative that Ship 24 would be held over until SpaceX is ready to commence testing Starlink deployments with Starship.

Animated showing how the payload slot on Ship 24 and Ship 25 could release multiple Starlink satellites. Credit: OweBL

However, Ship 25 has also now been fitted with a similar mechanism, suggesting that it will be a feature of Starship vehicle during at least the next phase of development. If so, it would fit with the idea that SpaceX would like to demonstrate Starship’s ability to deliver payloads to orbit as soon as possible, even if other aspects of the system are still in development.

Nor is this the end of progress over recent weeks:

  • The SpaceX launch faculties at Kennedy Space Centre’s Pad 39A have seen the foundations for the new Starship / Super Heavy launch facilities start to come together.
  • At Roberts Road just a few kilometres away, the sections of the massive orbital launch tower are being assembled in parallel, with each section additionally being outfitted with all the required plumbing, ducting, etc., it requires.
  • This means that when ready, it should be possible for SpaceX to rollout, secure, stack and connect the sections into a finished tower in relatively short order compared to the construction of the tower at Boca Chica, which was erected in stages and the plumbing added after initial construction was completed.
From early April: four sections of the Starship / Super Heavy launch support tower under construction at Robert Road, Kennedy Space Centre (KSC). When complete, this section will be moved to the launch facilitates under construction within Pad 39A at KSC. Credit: Julia Bergeron / NASA Spaceflight.com
  • Also at Robert’s Road, work on the new fabrication and assembly facilities for Super Heavy boosters and Starship vehicles is moving forward.
  • All of this progress has perhaps been why SpaceX appear to have abandoned – or at least delayed – the development of a second orbital launch facility at Boca Chica (although this might also be in order to head-off any negative findings by the FAA on those plans when the latter’s environmental study and recommendation is finally published).
  • one of the two oil rigs SpaceX purchased for offshore launches has also completed the first stage of refurbishment – the removal of all equipment and elements not required for its use as a floating launch platform – and has been relocated in preparation for more extensive fitting-out to commence.

There is a long way to go before the Starship / Super Heavy system proves itself – from being able to launch successfully through to the routine and safe recovery of both boosters and starship vehicles to demonstrating the system is safe for human flight, let alone routinely flying with crews / passengers or being ready to meet the company’s long-term goal of reach Mars (a very different proposition to launch / landing here on Earth). However, there can be no denying the determination of SpaceX to develop, iterate and expand along their development path.

Space Sunday: balloons, rockets, rovers, returns

A cabin at the edge of space. Credit: Space Perspective

Almost a year ago, I wrote about a company called Space Perspective and their plan to offer fare-paying passengers the chance to experience high-altitude balloon flights which, while failing to cross (or even come close to) the Kármán, will give the unique experience in rising to altitudes sufficient enough to witness the curvature of the Earth and see first-hand the tenuous nature of our protective atmosphere. And to do so in unique comfort.

As I reported in Space Sunday: balloons to space, Mars movies and alien water clouds, Space Perspective intend to offer passengers a six hour trip into the upper atmosphere aboard a luxury capsule slung beneath a gigantic helium balloon. And the price? US $125,000 per person – which sounds a lot, but is actually half that charged by Virgin Galactic for a flight lasting around 65 minutes, and who knows how much cheaper than a 12-minture trip aboard a Blue Origin New Shepherd vehicle.

A typical Space Perspective flight. Credit: Space Perspective

Obviously, both Virgin Galactic and Blue Origin have the added attractions of allowing passengers to experience microgravity for about three minutes and then collecting their (unofficial) astronaut wings on their return – neither of which are part of Space Perspective flights; which “only” rise to around 30-32 km. However, the watchword for Space Perspective trips is going to be a level of comfort well beyond anything Virgin Galactic or Blue Origin can achieve.

Just how much comfort has now been revealed by Space Perspective as they start to move ahead with the design of their full-scale Neptune capsule. In particular, the company has released a 3D interactive model of the capsule’s interior, demonstrating the 4 pairs of passenger seats located on other side of the capsule, the central bar / snack area alongside the access door.

The bar area and boarding door on Neptune. Credit: Space Perspective

In addition, the capsule has mood lighting and includes something necessary for a 6-hour flight: a lavatory (complete with its own window of its own so those needing it can continue to enjoy the view!). The passenger seats are designed to conform to the sitter’s body to offer maximum comfort and are fitted with fold-away tray tables. Potted plants add to the overall ambience while the floors and walls of the capsule covered in fabric to absorb sound and add to the sense of privacy.

Finally, the bar can be loaded with snacks and beverages in according with passenger’s preferences, whilst a central information display and wall-mounted tablets provide information on a flight. In addition the cabin will be equipped with wi-fi connectivity back to Earth, and heads-up displays may be included in the windows to help point out locations of interest visible beneath the clouds some 20 kilometres below the capsule as it cruises at altitude.

A view across Neptune, with the toilet on the left. Note to low-level lighting. Credit: Space Perspective

Flights will comprise a land-based launch From the Florida Space Coast with a 90-minute ascent to cruising altitude. The capsule will remain at its cruising altitude for around two hours before starting an equally gentle descent with a splashdown on water where the will be met by a support ship / yacht that will offer comfortable facilities to the passengers while the capsule is recovered, and then return them to land.

Should problems occur with the balloon during any phase of a trip, ground controllers can command the capsule to detach and drop aerodynamically to an altitude where parachutes can be deployed to slow the descent and cushion splashdown.

Space Perspective has recently secured a further US $40 million in funding to allow development of the full-scale Neptune capsule to proceed, and has secured the first of three hoped-for patents relating to the capsule’s unique structural design. In addition, the company states it already has 600 people who have paid for seats on flights, which are due to commence in 2024.

SLS: WDR Halted, Rocket to Return to VAB

In what is fast becoming something of a humiliating train of events in trying to get its first Space Launch System (SLS) rocket ready for launch, NASA has abandoned the critical wet dress rehearsal (WDR) and will be returning the rocket to the Vehicle Assembly Building (VAB) for a series of updates.

As I’ve reported over the last few week, the WDR is a last, critical step in ensuring the rocket and all its support systems – the mobile lunch platform, the propellant loading system, the launch control systems, etc., are ready to make a launch attempt. After been rolled out to launchpad 39B at Kennedy Space Centre, the WDR started on April 1st, and should have lasted three days.

However, that initial attempt had to be twice scrubbed as a result of issues within the supply of nitrogen gas (used to help purge and cool part of the launch system) to the vehicle. Correcting these issues took several days, prompting a further delay in resuming the test to make way for the launch of the Axiom Ax-1 private crew to the space station from the SpaceX facilities at neighbouring Pad 39A (see: AX-1 Artemis, ESA & a galaxy far, far away).

Launch Complex 39 at Kennedy Space Centre: in the foreground, the SpaceX / Axiom AX-1 stands on launch pad 39A. In the distance sits the NASA Artemis 1 SLS rocket on pad 39B. This picture was taken on April 6th, 2022. Credit: NASA

The intention had been to resume WDR processing on April 9th, but on April 7th, a fault was detected in pressure valve in the rocket’s upper Interim Cryogenic Propulsion Stage (ICPS). Rather than delay the test for at least a couple of months by returning the rocket back to the VAB to fix the faulty valve, NASA determined a process by which the test could continue with only “minimal loading” of the tanks on the ICPS, and pushed the resumption of the test back until at least April 12th to allow the necessary procedures to be properly revised.

Operations in fact resumed on April 14th – and almost immediately came to a halt due to propellent loading issues with the liquid oxygen. No sooner was this triaged and fixed than an over-pressure situation was detected within the liquid hydrogen tank, again bringing operations to a halt. After reviewing the situation again, NASA tried once more to resume propellant loading in a “modified” state, only for a hydrogen to be detected leaking from an umbilical line connecting the core stage to the mobile launch tower, again bringing operations to a halt.

The cause of the leak was found to be with the same nitrogen feed / purge system that caused the original problems at the start of the WDR process on April 1st. As a result, NASA announced late on April 16th that all WDR activities are now curtailed, and the rocket will be rolled back to the VAB to allow the problems with the nitrogen umbilical system to be addressed, and the valve in the ICPS to be fixed or replaced. The roll back will also be used to further investigate the liquid hydrogen over pressure issue on the core stage tank.

No date has been given on when the roll-back will occur  – there will be a further meeting to discuss this on April 18th. However, the move does mean that any Artemis 1 launch is unlikely to come before July at the earliest. However, to present further delays once the vehicle has been returned to the pad, mission managers are said to be considering – assuming the WDR runs flawlessly – moving directly from the test to launch readiness preparations without again returning the vehicle to the VAB for post-WDR inspections.

Continue reading “Space Sunday: balloons, rockets, rovers, returns”

Space Sunday: Ax-1 Artemis, ESA & a galaxy far, far, away

Crew Dragon Endeavour docked with the forward port on the US Harmony module at the ISS, and bearing the Axiom logo. Credit: NASA

The first entirely private sector mission to the International Space Station (ISS) lifted-off from the SpaceX Falcon launch facilities at Pad 39A, Kennedy Space Centre (KSC) on Friday April 8th, 2022, carrying a crew of four to the station aboard the Crew Dragon vehicle Endeavour.

The launch took place at 16:17 UTC, with the Falcon 9’s first stage making a flawless ascent prior to upper stage separation, then completing a boost-back manoeuvre and a successful return to Earth to land on one of the SpaceX autonomous drone ships. It marked the 5th successful flight for the core stage, which coincidentally was the same stage that launched the first all-private mission to Earth orbit – Inspiration4 (see: Space Sunday: Inspiration4 and Chinese flights) in September 2021.

Ax-1 has been seen by some as just another jolly jaunt into space by those who can afford it; however and in fairness, it is slightly more than that. Axiom Space was founded to create the world’s first commercial space station. While others have since entered this arena, Axiom has been granted access to the forward port of the ISS’ Harmony module, to which Axiom plans to dock the Axiom Orbital Segment; a complex that could grow to five pressurised modules after 2024.

Axiom’s plans for their space station (click for full size). Credit; Axiom Space

In order to help finance their plans, Axiom plan to offer a series of fare-paying flights to the ISS, with the 8-10 day Ax-1 being the first. However as a part of these flights, those paying for seats will also help Axiom pave the way towards their goal in bringing their first module to the ISS in 2024 and carry out a suite of selected on-orbit studies and experiments.

Commanding the mission is Michael López-Alegría, who was one of NASA’s most experienced astronauts prior to retiring in 2012. He holds the US record for the most EVAs undertaken by a NASA astronaut (10 totalling 67 hours and 40 minutes) and is also (and quite separately) licensed to officiate at wedding ceremonies. In 2017, he joined Axiom Space as their director of Business Development, and allowing him to regain his space flight status. Joining him on the mission are US entrepreneur  Larry Connor, Israeli businessman and former fighter pilot Eytan Stibbe and Canadian philanthropist and businessman Mark Pathy, each of whom paid an estimated US $55 million to join the mission.

The Ax-1 crew: from left – Larry Connor Mark Pathy Michael López-Alegría and Mark Pathy. Credit: Axiom Space / SpaceX
Endeavour took a gentle path up to the space station over a 20 hour flight; however, docking was delayed by some 45 minutes due to an issue with the video system used by the ISS crew to monitor docking operations.

Following post-docking checks, the hatches between Endeavour and the ISS were opened, and the Ax-1 team were welcomed aboard the station by the 7-person crew. During a brief ceremony-come-video press briefing, López-Alegría – who had become the first former astronaut to return to the ISS – presented his three fellow crew members with astronaut pins. Whilst not official US astronaut pins, those presented to Stibbe, Connors and Pathy have been designed by the Association of Space Explorers, which encompasses a lot of members from 38 different countries that have flown astronauts.

Alongside of their work in support of Axiom Space, the Ax-1 crew will take part in a multi-discipline science programme of some 25 different research experiments sponsored by the ISS U.S. National Laboratory in collaboration with the Mayo Clinic, the Cleveland Clinic, Canadian Space Agency, Montreal Children’s Hospital, Ramon Foundation (named for Ilan Ramon, the Israeli astronaut killed in the Space Shuttle Columbia disaster of 2003) and Israel Space Agency.

The Axiom Ax-1 crew (to the rear) with their ISS colleagues, around them in the foreground – counter-clockwise from right: NASA astronaut Tom Marshburn (holding the microphone) ; Roscosmos cosmonaut Oleg Artemyev (in the blue, centre); NASA astronaut Kayla Barron; cosmonauts Sergey Korsakov and Denis Matveev (floating); and upside down NASA astronauts Raja Chari and ESA astronaut Matthias Maurer. Credit: NASA

As a fully private mission to the ISS, Ax-1 not only features a non-government crew launched aboard a private sector space vehicle and rocket, it is also being managed through the SpaceX flight control centre, Hawthorne, California and Axiom’s own mission control centre in Houston, Texas.

Artemis WDR: Further Issues and Delay

The Wet Dress Rehearsal for the Artemis 1 Space Launch System (SLS) vehicle at KSC’s Pad 39B continues to hit niggling problems, with a resumption of testing now pushed back until April 12th.

As I noted in my previous Space Sunday report, while it had been hoped this full test of a launch countdown procedure, including fuelling the massive rocket’s liquid propellant tanks, could be completed in a 3-day period between April 1st and April 3rd, the test ran into a series of issues that caused efforts to be scrubbed on two occasions.

The issues were now with the rocket itself, which performed flawless during the tests up until the scrubs were each called, but with support systems within the vehicle’s mobile launch tower. However, after the second set of issues on April 3rd caused a scrub, the plan had been to investigate and correct the issue in time to resume the countdown on April 4th and complete the tests ahead of the launch of the SpaceX / Axiom Ax-1 mission reported above – a launch that had already been postponed from April 3rd.

Artemis 1 and its mobile launch platform on Pad 39B at Kennedy Space Centre. Credit: NASA

As the investigations took longer than planned, on April 4th, the decision was taken to stand down WDR operations to allow the Ax-1 to go ahead, and to resume the tests on April 9th. But on April 7th, during a check on the rocket’s systems, engineers found a problem when trying to maintain helium purge pressure in the Interim Cryogenic Propulsion Stage (ICPS), the upper stage of the rocket itself.

The ICPS is based on the second stage of the Delta 4 launch vehicle. It uses a single RL10 engine to propelled the payload carrying section of the rocket – although it will be replaced by the more powerful and purpose-built Exploration Upper Stage from the third SLS flight (Artemis 4) onwards. This particular ICPS was one of the first to be completed, and had been in storage for several years awaiting the completion of the Artemis 1 core stage and boosters.

The Artemis 1 ICPS at Kennedy Space Centre, prior to its integration with the rest of the SLS rocket. Credit: NASA

The issue was traced to a check valve intended to prevent helium – used to purge propellant lines and drain propellant – from escaping the rocket., the valve failing to function as intended. To allow time for a possible fix for the problem to be developed and attempted, the decision was taken to push test resumption by to April 12th. Unfortunately, by April 9th, it became clear that the valve would need to be replaced; but rather than cancel the WDR completely, NASA has decided to complete the test as planned on the 12th – but to only perform a “minimum fill” of the ICPS tanks;  enough to prove the propellant loading system works. This, with a full load of the core stage tanks is seen as sufficient for the WDR to be completed.

Replacing the check valve will be carried out once the rocket has been returned to KSC’s Vehicle Assembly Building as a part of the post-WDR checks. However, this means that any chance of Artemis 1 making the hoped-for May launch window is now out of the question, whilst NASA is confident replacing the valve will correct the issue, it is also unlikely the turn-around can be completed in time for the rocket to make the June 6th through 16th launch window, potentially making July the earliest Artemis 1 launch opportunity.

Continue reading “Space Sunday: Ax-1 Artemis, ESA & a galaxy far, far, away”

Space Sunday: distant stars, sounds on Mars, a return and a rocket

The Artemis 1 Space Launch System (SLS) rocket stands on its mobile launch platform at Kennedy Space Centre’s Pad 39B, where it is undergoing a full wet dress rehearsal ahead of its launch later this year – see later in this article for more. Credit: NASA

The Furthest Star

My previous Space Sunday update ended with a note that NASA would be making an announcement at the end of March 2022 concerning a new discovery by the Hubble Space Telescope (HST) that could have repercussions for the James Webb Space Telescope (JWST), once it commences its scientific mission. Announced on March 30th, that discovery was revealed to be the imaging of the most distant individual star from Earth yet discovered. So distant, in fact, that it has taken the light from it 12.9 billion years to reach us. By contrast, the next oldest individual star we have detected using Hubble was born when the universe was already some 4 billion years old, taking 9 billion years to reach us.

Christened  Eärendel, the Old English term for “morning star” (and, as Tolkien fans like me will know, was the name initially given to the half-human, half-elven navigator, prior to Tolkien changing the name of that character to Earendil), the star was discovered as a part of a HST programme called RELICS -the REionisation LensIng Cluster Survey, intended to capture to light from really far distant objects born not long after the Big Bang.

To do this, RELICS employs the phenomenon of gravitational lensing, whereby the mass of a huge object such as a galaxy or cluster of galaxies bend and focuses the light coming from objects far beyond them, allowing us to see them as magnified, arc-like objects. In this case, a cluster of galaxies called WHL0137-08 was found to be lensing the light of a galaxy far beyond them, drawing the collected light of that galaxy out into a slender crescent Hubble could see and which astronomers nicknamed the Sunrise Arc.

The red arc of the Sunrise Arc galaxy, and within it, the single point of light of Eärendel. Credit: NASA, ESA, Brian Welch (JHU), Dan Coe (STScI)

For the most part, the Sunrise Arc is blurred and instinct, like sunlight diffracted by the ripples on the surface of a swimming pool cast blurred clouds of light on the bottom of the pool. However, by coincidence, at the time the images of the Arc were recorded, Eärendel appeared directly on, or extremely close to, a curve in space-time that provided maximum brightening, allowing its light to stand out as an individual point within the blurriness of the Sunrise Arc – just like some rays of light can strike the surface of a swimming pool at precisely the right moment to avoid diffraction by the surface ripples and form pinpoints of light on the bottom of the pool rather than being blurred.

Initially it was thought that the star might in fact be a cluster, rather than a lone star, but careful analysis of Eärendel ‘s red shift has swayed astronomers towards believing it is most likely just the one star (although the potential for it to be a binary system hasn’t been entirely ruled out) of enormous size at least 50 times the mass of the Sun and correspondingly enormous luminosity.

Such is Eärendel age, that it at the time its light departed it, the star was likely only made up of primordial hydrogen and helium following the Big Bang. This makes it a prime target for study by JWST – which thanks to is infra-red capability can pick out more information about a target object than HST -, as doing so could reveal more about the state of the early universe and early stellar development.

However, such is the nature of things that – whilst referring to the star in the present tense, it’s important to note that it is very likely that while the most distant individual star observed by HST, Eärendel is not the oldest star yet found; in fact, it probably no longer exists. This is because such supermassive stars tend to burn through their available fuel stocks in mere millions of years, rather than billions. It’s therefore very likely that at some point when the light captured by Hubble was still making its way towards us, Eärendel either violently exploded into a supernova, or collapsed into a black hole – something we’ll only know for sure a few million years into our future.

The Nature of Sound on Mars

We’re all familiar with the concept of the speed of sound. Here on Earth and at sea level, with the temperature at 20ºC, sound travels at 343 metres per second (m/s). However, that is not an absolute; it varies according to the relative atmospheric temperature and density. At altitudes up to 20 km, the speed of sound slowly declines due to the thinning of the atmosphere; however, above 20 km, whilst the atmosphere continues to thin, its temperature actually increases, making it more excitable, and so the speed of sound increases once more.

Much the same was thought to be true on Mars, where the relatively thin atmospheric density close to the surface of the planet was thought to limit sound waves to around an average of 240 m/s (again, allowing for variations in temperature).  However, what no-one expected was that the speed of sound would vary according to frequency – but that is what the Mars 2020 mission has revealed.

An international team of scientists reached this conclusion after analysing recordings made by one of two microphones mounted on the Perseverance rover. The SuperCam microphone mounted at the top of the rover’s mast is somewhat directional in nature in that turning / tilting the SuperCam unit allows the microphone to be pointed directly at sound sources, allowing it to record them with a good level of fidelity.

The Mars 2020 rover’s SuperCam system with the “directional” microphone highlighted. Credit: NASA/JPL

This is been done a number of time during the rover’s mission. For example, the camera has been pointed towards the Ingenuity Mars helicopter, allowing it to directly record the low-frequency beating of the helicopter’s rotors. It is also naturally pointing at rockets targeted for “zapping” by SuperCam’s laser. It has also been able to listen to tools and equipment operating at the end of the rover’s robot arm. All of these sounds have now been collectively analysed, and scientist have been surprised to find that while lower frequency sounds – such as the beating of Ingenuity’s rotors – travel at the expected Martian average of 240 m/s, sounds at frequencies greater then 240 Hertz, such as the higher-pitched click-click-clicking of the SuperCam laser actually travel around 10 m/s faster – the first time this has ever been observed.

The cause for this unusual difference is thought to be the result of the Martian atmosphere being largely carbon-dioxide. In studying the tenuous Martian atmosphere, scientists have discovered during the day, the heat of the Sun, deflected as it is by the surface of the planet, generates an unusual turbulence in the first 10 km of atmosphere above the planet. This turbulence has an unusual impact on the carbon dioxide that isn’t seen in Earth’s denser atmosphere: it allows higher frequency sounds to excite the carbon dioxide molecules a lot more than low-frequency sounds, allowing such higher frequencies to be more rapidly transmitted through the atmospheric medium.

Because this effect happens almost smack in the middle of the bandwidth of sounds audible to the human ear, it means that if we were able to stand out in the open on Mars and listen to something like a symphony being played a few 10 of metres away, rather than hearing all the notes collectively as we would on Earth, we’d hear the higher notes a second or so ahead of the lower notes, resulting in a discordant mess. However, a more practical outcome of this discovery is that engineers believe that by listening to the different frequencies within the sounds made by various pieces of audible equipment on the rover, they could potentially identify if that part of the rover is experiencing issues, and thus be forewarned that action might be required well before a potential failure occurs.

Continue reading “Space Sunday: distant stars, sounds on Mars, a return and a rocket”

Space Sunday: Starship, ExoMars and sundry news

What it might look like: an animation of the first Starship orbital flight. Credit: C-Bass Production / Neopork

Such is the pace of development, the first orbital flight of the SpaceX Starship / Super Heavy combination will now not take place as originally planned.

It had been thought that the flight, which has been repeatedly delayed for a number of factors, including slippages in the Federal Aviation Administration being able to publish the final version of its study into the impact of SpaceX’s operations in Boca Chica on the surrounding environment, would be made by Starship No. 20 (“Ship 20”), and Super Heavy booster No 4 (Booster 4), both of which have been going through a wide range of cryogenic and static fire tests since mid-2021, the most recent of the cryogenic tests occurring just over a week and a half ago, with both vehicles stacked together on the launch platform.

However, on Saturday, March 22nd, Starship 20 was “destacked” from Booster 4 and removed from the orbital launch facilities, and 24 hours later, Booster 4 was also removed, with Elon Musk Tweeting that neither would now play a role in the first orbital flight attempt. The reason for this is simple: work on developing and enhancing the design of both the Starship vehicle and the Super Heavy booster now means that Booster 4 and Ship 20 are essentially obsolete.

March 22nd, 2022: Mechazilla on the orbital support tower lowers Starship 20 following its disconnect from Booster 4. Credit: NASA Spaceflight

The major cause for this is that – despite a scary e-mail from Musk at the end of 2021 stating SpaceX could go bankrupt if issues with the powerful Raptor 2 engine were not quickly sorted out and production ramped – the company is now solely focused on boosters and ships built to mount the much more compact Raptor 2 motors, the sea level versions of which (primarily used to power Super Heavy, but three are also used in each Starship) are considerably smaller and less complicated than their Raptor 1 cousins, and generate far more thrust (from 230 to 250 tonnes per Raptor 2 compared to a maximum 185 tonnes for a Raptor 1).

Left: a sea-level Raptor 2 engine compared to its much larger Raptor 1 equivalent. Credit: Nic Ansuni / NASA Spaceflight

The more compact size of the Raptor 2 makes it possible for SpaceX to increase the total compliment of engines on a Super Heavy from 29 to the planned 33. The reduction in their complexity also makes all of the plumbing required  to feed them propellants and the electronics needed to control them  a lot easier to manage. For starship vehicles, the smaller Raptor 2 motors should make it easier to increase the number of engines from 6 to the planned 9 (3 sea-level and 6 vacuum engines with their much large exhaust bells).

Booster 7 and Ship 24 are also the first of each design to incorporate other critical design changes. Some of these are to easy the fabrication and assembly process, others are to help improve performance or meet the demands of having more engines, and still other to improve aerodynamics.

In the case of the Super Heavy booster, one of the cleverest – and most visible – changes is in the number and positioning of the Composite Overwrapped Pressure Vessels (COPVs).

COPV are tanks of hydrogen used in the ignition process for the outer ring of Raptor motors on a Super Heavy. With Booster 4, four pairs of COPVs were placed equidistantly around the base of the booster, covered by steel aeroshells.

However, with the increased number of Raptor engines, Booster 7 and those that follow it require 10 COPVs each. Were the extra two COPV to be paired at the base of the rocket, they would work with the other four pairs to disrupt airflow over the tail of the booster during ascent, generating both drag and potential buffeting / vibration.

To prevent this, Booster 7 is the first Super Heavy to have the COPV stacked vertically along its sides in two sets of five. Not only does this remove the risk of additional drag / buffeting during ascent, it also simplifies the overall plumbing to supply hydrogen to the Raptors, as each set of 5 can use common feedlines down the the engines. However, what is particularly clever is that offsetting each stack of COPVs slightly from the rocket’s centreline, their aerodynamic covers can actually help generate a degree of lift around the base of the rocket during its descent back through the atmosphere, helping to both slow it and provide a greater degree of control during the descent.

The COPV changes: left, as they were on Booster 4, and as they are on Booster 7. Credit: Brendan Lewis / ChameleonCir

As it is the closest to completion, Starship 24 would appear to be the primary candidate for joining booster 7 on the orbital flight attempt (work on ships 21 through 23 having been abandoned / bypassed) – but this far from certain. Recent work on the vehicle has seen it installed with a small prototype payload bay door, suggesting it has been earmarked for a payload bay test flight, something yet to be scheduled. As such, it is possible that Ship 25, also being assembled at Boca Chica, might be selected for the first orbital attempt.

Although the switch to using more recent versions of Super Heavy and Starship means that the first orbital flight attempt is now unlikely to occur before late May 2022, when it does happen, it will allow SpaceX to gather more relevant data on vehicle performance, which should help benefit the programme overall. It also means that by the time the booster / ship combination is ready to go, the FAA’s report on its environmental review of the Boca Chica site should have been published (the release date was recently pushed back again from the end of March to the end of April), and SpaceX should be in a position to know whether or not they are to be granted a licence for their orbital launches from the site.

Continue reading “Space Sunday: Starship, ExoMars and sundry news”