Space Sunday: aiding three space telescopes

The Hubble Space Telescope, the Chandra X-Ray Observatory and the Spitzer Space Telescope. Credits: NASA

They are the grande dames, so to speak, of space-based astronomy, observatories launched into orbit around Earth and the Sun to provide us with unparalleled insight into the cosmos around us, born of ideas dating back to the early decades of the space age. They form three of the four elements of NASA’s Great Observatories programme, and all operated, or continue to operate well beyond their planned life spans; they are, of course, the Hubble Space Telescope (HST – launched in 1990), the Chandra X-Ray Observatory (CXO and formerly the Advanced X-ray Astrophysics Facility or AXAF – launched in 1999), and the Spitzer Space Telescope (SST, formerly the Space Infrared Telescope Facility or SIRTF – launched in 2003).

Today, only Hubble and Chandra remain operational. The fourth of the observatories (and 2nd to enter space after Hubble), the 16.3-tonne Compton Gamma Ray Observatory (CGRO), had its mission curtailed in June 2000, after just over 9 years, when it suffered an unrecoverable gyroscope failure. With fears raised that the failure of a second unit could leave the observatory unable to control its orientation, the decision was made to shut it down and de-orbit it in a controlled manner so it would break-up on entering the atmosphere and any surviving parts fall into the Pacific Ocean, rather than risk an uncontrolled re-entry which could shower major pieces of the observatory over populated areas.

Whilst the “youngest” of the surviving three observatories, Spitzer was placed into a “safe” mode in January 2020, ending 16.5 years of service. By then, the nature of the observatory’s orbit – it occupies a heliocentric orbit, effectively following Earth around the Sun  – were such that it was having to perform extreme rolls back and forth in order to carry out observations and then communicate with Earth, and these were affecting the ability of the solar arrays to gather enough energy to charge the on-board batteries. The “safe” mode meant that Spitzer could continue to recharge its batteries and maintain electrical current to its working instruments, potentially allowing it to be recovered in the future. However, while it is true that Hubble and Chandra continue to work, neither is without problems.

Hubble orbits close enough to Earth that even at over 500km, it is affected by atmospheric drag, causing it to very slowly but inexorably lose altitude. This used to be countered through the semi-regular servicing missions, when a space shuttle would rendezvous with HST to allow astronauts to carry out work, and then gently boost the telescope altitude using its thrusters. But the shuttle is no more, and the last such boost was in 2009 to 540 km; currently Hubble is at around 527 km, and at the present rate of decent, it will start to burn-up in another 10-15 years. However, a boost now could see Hubble – barring instrument / system failures – continue to operate through the 2050s.

The Hubble Space Telescope sitting on its holding platform in the cargo bay of the space shuttle Atlantis in 2009, seen through the orbiter’s rear deck windows during the 5th and final (and most extensive) servicing mission. Credit: NASA

Chandra, meanwhile, faces a different challenge. It lies in a highly elliptical orbit around the Earth, varying between 14,508 km at its closest and 134,527 km at its most distant. It has therefore been operating untended for its entire operational life, and is starting to show signs of wear and tear. In 2018, it suffered a glitch with one of the gyroscopes designed to keep it steady during observations (and orient it to look at stellar objects). Whilst the gyroscope was recovered, it was put into a reserve mode lest it fail again. This led to fears that should a second gyro fail, either orientation control might be lost if the 2018 gyro fail to come back on-line correctly to take over the work. Also, and while the main science instructions are in good order, they are aging and presenting concerns as to how well they are actually doing.

Ideas for both boosting Hubble’s orbit and carrying out a robotic servicing of Chandra have been floated for the last few years – but there are now signs both might actually get potentially life-extending missions.

In December 2022, NASA issued an RFI on how Hubble’s orbit could be boosted, and have received eight responses, one of which has also been publicly announced and would seem to offer potential. It involves two companies: Astroscale Holdings and Momentus Space, a US-based company. The former is in the business of clearing space junk from Earth’s orbit, and has already flown prototype vehicles capable of doing this in orbit. This includes the ability to carry tools to mate or grapple junk and then move them. Momentus, meanwhile, are in the satellite servicing business and recently demonstrated a small “space tug” in orbit that was largely successful in meeting its mission goals (7 out of nine small satellites deployed into individual orbits).

In their proposal, the two companies indicate Momentus would provide a variant of their tug, and Astroscale a dedicated capture tool designed to use the grapple holds on Hubble. Following launch, the Momentus craft would self-guide itself to Hubble’s orbit and rendezvous with it using the Astroscale mating tool. Once attached, the Momentus vehicle would use its thrusters to gently raise Hubble’s orbit by 50 km, then detach. The vehicle could then be used to remove orbital debris in orbits approaching Hubble, thus protecting it from the risk of collision.

NASA has yet to comment on any of the proposals received under the RFI, but the Momentus / Astroscale option, using equipment already being flight-tested and refined and which is of relatively low-cost, would appear to be a real option.

A similar, but more expensive and complex idea has been proposed by Northrop Grumman – the company effectively responsible for building Chandra – to help keep the X-Ray observatory going. This would involve the construction and deployment of a “mission extension vehicle”, a “space tug” capable of departing Earth and gradually extending and modifying its orbit to rendezvous with Chandra and link-up with it, taking over the operations related to orienting and steadying the platform using gyros, potentially extending the mission by decades.

This is important because Chandra has already proven invaluable in supporting the James Webb Space Telescope (JWST) which operates in the infra-red. The ability to observe targets in both X-ray and infra-red can reveal a lot more about them.

A set of X-ray images of regions of space – including supernova remnants and merging galaxies – captured by the Chandra X-ray Observatory, released by NASA in 2009 to celebrate the telescope’s 20th anniversary. Credit: CXC/NASA, SAO

NASA has given no word on whether it would finance such a mission, although Northrop Grumman has apparently forwarded the results of its own study on the idea to the US agency. However, given the most recent U.S. decadal survey in astrophysics, released in 2021, included mention of a new X-ray telescope to replace Chandra, a servicing mission – even one this complex – capable of extending Chandra’s operations for decades at a fraction of the cost of a new telescope, which itself would take years if not decades to develop, could be highly attractive.

Continue reading “Space Sunday: aiding three space telescopes”

Space Sunday: China, stations and bits

An artist’s impression of the Chinese lunar base by the late 2030s. Credit: Chinese Lunar Exploration Programme

China has been making a lot of space-related news recently, so it’s time to catch-up on things.

At the end of April, the country confirmed it intends to have boots on the Moon by 2030. This confirmation came during a wide-ranging interview with Wu Weiren, the head of the country’s lunar exploration programme, broadcast in China ahead of the “national Space Day”, held on April 24th.

As with the US-led Artemis programme, the Chinese aim to start with a short-term stay on the Moon, followed by additional missions intended to build up to a permanent presence within a research base called the International Lunar Research Station (LRS) by the end of the 2030s.

The CLEP logo of the crescent Moon and tiakonaut boot prints, combined to resemble the Chinese symbol for the Moon

In support of this, China is operating a highly integrated development programme – the Zhōngguó Tàn Yuè (Chinese Lunar Exploration Programme (CLEP) – overseen by Wu. This combines the development and operation of on-going and future robotic mission to the Moon along with the longer-term development of crew vehicles either designed specifically for, or in support of, lunar exploration. These activities fold into them the existing orbital and soft-landing missions of Chang’e 1 through Chang’e 5, and will continue in May 2024.

It is then that China will launch Chang’e 6, a mission to investigate the topography, composition and subsurface structure of the South Pole–Aitken basin, one of the sites seen as a potential location of a future lunar base. This mission will also see an attempt to return further lunar sample to Earth – the first time samples have been returned from the Moon’s far side.

Then in 2026, Chang’e 7 will visit the same region, leaving a communication relay satellite in orbit and delivering a lander and a miniature flying probe to the surface; in 2028, Chang’e 8 is likely to deliver of a small-scale 3D printing system intended to demonstrate the use of the Moon’s regolith in the construction of a lunar base.

As well as the Chinese mission, Russia is expected to provide input to the programme as the first major partner to join with China in their lunar ambitions. This involvement is due to commence later in 2023 with the launch of the Luna 25 lander, to be followed by the Luna 26 orbiter and Luna 27 lander missions in 2027 and 2028 respectively. Russia will also provide personnel and equipment for the LRS.

Alongside of this, the China Aerospace Science and Technology Corp. (CASC) will work on crewed vehicles for transporting taikonauts to the Moon and delivering them to the surface and then back to orbit. If the plan progresses as intended, it is expected that the first phase of the International Lunar Research Station in operation by 2035 – potentially mirroring or possibly ahead of the US plans for an expanded Artemis base in the Moon’s South Polar Region.

Most recently for China has been the return to Earth of their ultra-secretive Chongfu Shiyong Shiyan Hangtian Qi (CSSHQ), an experimental spaceplane after 276 days in orbit.

An artist’s impression of China’s reusable Shenlong spaceplane. Credit: China Aerospace Studies Institute

Quite what the vehicle is remains unclear to western analysts – and matters have been muddled by differing statements made by Chinese authorities (some of which are doubtless intended to obfuscate matters), indicating that the vehicle is both an unscrewed cargo-carrying vehicle and a craft designed to carry a crew of 6 to orbit. However, this latter claim appears to be unrealistic; CCSHQ’s two flights have been aboard Long March 2F vehicles, which have a maximum payload capacity of 8.4 tonnes – but a vehicle capable of supporting a crew of six in orbit and returning them safely to Earth would have a mass well; perhaps as much as 20 tonnes at launch. The Chinese have also suggested the vehicle is a two-stage craft, using a scramjet engine for first stage propulsion.

The vehicle’s size approximates to that of the equally secretive X-37B spaceplane, some 8-9 metres in length and with a wingspan of between 3 and 4 metres. The May 8th return to Earth marks its second flight into space – the first being a modest 3-day flight in 2020.

The current mission commenced on August 4th, 2022, and gave rise to a lot of speculation when the vehicle deployed a small satellite, with some in the west claiming it was a  weapons platform – something China hotly denied. As it was, vehicle and cargo operated in close proximity to one another for a time, as if practicing rendezvous manoeuvres. In addition to this, CSSHQ performed more extensive manoeuvres, including altering its orbit, raising and lowering it.

The reusable test spacecraft successfully launched by our country at the Jiuquan Satellite Launch Centre successfully returned to the scheduled landing site on May 8 after flying in orbit for 276 days. The complete success of this test marks an important breakthrough in our country’s research on reusable spacecraft technology, which will provide a more convenient and inexpensive way to and from the peaceful use of space in the future.

– China Aerospace Science and Technology Corp. (CASC) statement

The Chinese space plane is roughly the same size and the US X-37B, shown above in its former USAF marking. Credit: Giuseppe De Chiara

As with the first mission, the launch commenced from the Jiuquan Satellite Launch Centre in the Gobi Desert and while accounts vary, it appears to have concluded with the craft landing at the Lop Nur military base in Xinjiang, as it did at the end of its maiden flight.

Some in the west have been keen to play down this mission, noting that the X-37B’s first flight lasted 224 days, and its most recent – which ended in November 2022 – was908 days in length. However, the X-37B has a development history going back, and took a decade to extend its flight envelope from 224 to 908 days. CSSHQ appears to have been in development for less than a decade, and saw its mission duration leap from 4 days to 276 in just two flights – so it is hardly something to be sneezed at purely on the basis of flight duration.

Vast Contract SpaceX to Launch “World’s First Commercial Space Station”

Vast (also styling itself Vast Space), a privately held American aerospace company founded in 2021, has announced ambitious plans to launch the world’s first commercial orbital facility, Haven-1 in August 2025, and that they have engaged SpaceX to handle the launch and deliver at least one 4-person crew to the station.

“Ambitious”, because prior to February 2023, all Vast has was a mission statement (to build artificial gravity space stations), a logo and a 10,700 square metre facility in Long Beach California; outside of the founders, it did not even have employees. That changed in February with the acquisition of another start-up, Launcher, a company developing 3D printed rocket motors and an orbital transfer vehicle; this afforded Vast assets, products – but not the expertise required to build a module capable of supporting 4 people in orbit for up to 30 days at a time.

An artist’s impression of the Vast Haven-1 module with a Crew Dragon docked against it. Credit: Vast Space LLC

However, Vast claim they can reduce the time required to build the unit by “repurposing” elements of the automated orbital transfer vehicle. If true, this still leaves them having to ensure the 10.1 metre by 3.8 metre module is fully capable of supporting life – something which is not a priority for robotic vehicles.

In addition, the module will have deployable solar panels capable of generating up to 15 kW of electrical power, a docking module at one end suitable for capturing Crew Dragon vehicles, and around 70 cubic metres of total pressurised volume. At 14 tonnes, it is intended to be launched with all the consumables needed to support a visiting crew during their stay, with additional crews able to carry further supplies with them aboard Crew Dragon.

Exactly what Haven-1 will be used for is unclear. “Research” has been mentioned, but it also seems to be about space tourism; as a part of a deal with SpaceX, which will see the module launched on a Falcon 9 rocket, Vast have committed to one 4-person Crew Dragon launch to the module (the “Vast-1” mission), and plan to sell these seat on to interested parties, who will also have to pay for training through SpaceX. The contract also includes the option to purchase a second Crew Dragon flight in 2026.

CAD drawings of the proposed “spinning stick” station (l) and a space wheel from Vast Aerospace, both of which will supposedly provide artificial gravity environments – the former by spinning the 7-metre diameter chain of modules around its longitudinal axis, a proposition that looks questionable at best. Credit: Vast Aerospace

Equally ambitious are the company’s longer-term plans. According to their website, they place to launch a much larger “Starship class” module with a diameter of 7 metres (but unspecified length) using the SpaceX Starship. This module class will then – they claim – be used to build 100-metre long “spinning stick” stations which will “provide various gravitational environments including Earth, Mars, Moon, and asteroid gravities” – although whether this is really practicable in a space just 7 metres across and spinning around its longitudinal axis is questionable at the least.

Vast claim these “spinning sticks” will be constructed over seven Starship launches apiece and support up to 40 people each, paving the way through the 2030s to a “proliferated space fleet” comprising “dozens” of stations of various types “across the solar system” in the 2040s. These, if the website is to be believed, will include units modelled on the classic “spinning wheel” stations beloved of science-fiction.

Just how well the company succeeds in these goals remains to be seen. I’m personally not holding my breath. I will give them full marks for the Haven-1 promo video, however.

Continue reading “Space Sunday: China, stations and bits”

Space Sunday: Ups and Downs

An artist’s rendering of the ispace HAKUTO-R M1 lunar lander. Credit: ispace

Japan’s first attempt at a lunar landing appears to have ended with the loss of the vehicle – once again proving that, for all its successes, spaceflight is nowhere close to being a certainty.

Launched by a SpaceX Falcon 9 in December 11th, 2023 on a low-energy ballistic trajectory that carried it 1.4 million km from Earth before starting on its return, with the Moon getting in the way to allow the vehicle enter an extended elliptical orbit on March 20th, 2023. Over the course of the next several weeks that orbit was circularised, allowing the vehicle to attempt a landing on April 25th.

Essentially a private mission – the lander was built by Tokyo-based ispace – the craft was carrying a set of private and government-sponsored payloads. Among them was Rashid, a small lunar rover developed by the Mohammed bin Rashid Space Centre in the United Arab Emirates, and a “transformable lunar robot” the size of a baseball from Japan’s space agency JAXA. Other payloads include cameras and technology demonstrations.

ispace originally started as a partner of Netherlands-based White Label Space, founded in 2008 to compete in the Google Lunar X Prize. The team then became White Label Space, Japan LLC. They then become Hakuto in order to compete directly in in the Lunar V Prize, developing the Sorato rover before finally transitioning into its present form. Credit: Syced

The landing was streamed live and appeared to initially go well, the HAKUTO-R M1 vehicle having survived its extended trip to the Moon with only minor issues, all of which ispace were able to rectify.  However, during the final part of the lander’s decent – whilst it was still some 80 metres above the lunar surface, close to Atlas Crater and descending at a rate of 48 km/h, the telemetry readings for the lander appeared to switch from live data to a simulation, with no subsequent confirmation of a safe landing or any further receipt of telemetry.

ispace initially acknowledged the potential vehicle loss 25 minutes after the planned landing. It came after repeated attempts at communication had failed; six hours after that, the company issued a statement confirming they believed the vehicle had been lost.

During the lander’s final approach to the surface [the] estimated remaining propellant reached at the lower threshold and shortly afterward the descent speed rapidly increased. Based on this, it has been determined that there is a high probability that the lander eventually made a hard landing on the Moon’s surface … it has been determined that Success 9 of the Mission 1 Milestones, successfully landing on the Moon and establishing communications, is no longer achievable.

– ispace announcement on the loss of the HAKUTO-R M1 lander

Despite the loss, Takeshi Hakamada, founder and chief executive of ispace, believes the mission yielded valuable data from both the development and flight of the M1 lander. This, he said would be fed into the company’s next lander mission – M2 – which is targeting a late 2024 launch. It will carry a set of customer payloads as well as a “micro rover” that ispace developed. That rover will collect a regolith sample that will be transferred to NASA under a 2020 contract awarded to ispace’s European subsidiary.

Ingenuity Snaps Perseverance

A panoramic view of Belva Crater captured by NASA’s Ingenuity helicopter during its 51st flight on April 22nd, 2023, the 772nd Martian day, or sol of the Mars 2020 mission. Within it can be seen – upper left and upper right edges – two of the helicopter’s landing feet, and just below and to the right of the image centre is the helicopter’s own shadow. Taken at an altitude of 12 metres, the picture also shows – top left (and just above and inboard of Ingenuity’s landing foot), at the foot of a create wall slope – the Perseverance rover. Credit: NASA/JPL.

Voyager 2 Gets Extended Mission Life

NASA engineers have developed a means to extend the science lifespan of their venerable Voyager 2 space probe beyond its already impressive 45 years – and could do the same for the Voyager 1 craft.

The twin Voyager programme vehicles, launched in August and September 1977 respectively, are the only human-made spacecraft to reach interstellar space.  Together, they are helping scientists understand the heliosphere, the protective bubble of particles and magnetic fields generated by the Sun, informing them as to its shape and its role in protecting Earth from the energetic particles and other radiation found in the interstellar environment. At the same time, the vehicles are helping those scientists also understand the nature of the environment beyond our solar system.

An artist’s rendering of Voyager 2 in deep space. Credit: NASA/JPL

However, whilst powered by radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium into electricity, the two vehicles have a limited source of power, the RTGs generating less and less electricity as the plutonium degrades.

Thus far, the flow of electricity to the science instruments has been maintained by means of turning off other systems as they’ve ceased being required – such as the high-power camera systems – and those which do not contribute to the science mission or communications. Nevertheless it has been estimated by late 2023, Voyager 2 would be unable to generate sufficient power to manage its instruments, and NASA would have to start turning them off one by one.

To avoid this, engineers carried out a review of the craft’s systems, and realised that the voltage regulation system, designed to protect the science instruments against unexpected surges in the flow of electricity to them, has a small percent of power from the vehicle RTG specifically dedicated to it; a reserve that isn’t actually required, as it also works off the primary supply. The decision has therefore been taken to release this reserve and allow the instructions access it.

This does mean that if there is a serious voltage issue on the vehicle, the regulator might not be able to deal with it – but as engineers note, after 45 years of continuous operations, the regulators on both of the Voyager craft have been perfectly stable and have never needed to draw on the reserve. While the amount of power freed-up by the move is small, it nevertheless means NASA can forestall any need to start turning off instruments until 2026.

The same approach can also be taken with Voyager 1, although the situation there is less critical at that craft lost one of its science instruments relatively early in the mission, leaving it with sufficient power to keep the remaining instruments through until the end of 2024 before decisions on releasing the power reserve needs to be taken.

Continue reading “Space Sunday: Ups and Downs”

Space Sunday: Starship orbital flight test

April 20th, 2023: the Starship combination of Ship 24 and Booster 7: (l) approaching Max Q, intact but with several engines shut-down; (r) tumbling as control is lost. Credit: SpaceX

Thursday, April 20th saw SpaceX attempt the first orbital flight test of their Starship / Super Heavy launch vehicle combination. As most reading this article likely already know, things did not go entirely well with the vehicle’s flight termination system (FLS) being used to destroy it just under  four minutes into its ascent.

The flight was always going to be a risk; the Starship / Super Heavy programme has been an extraordinary public display of a rapid development cycle (some might say too rapid), with little in the way of comprehensive systems and integration testing to match that of the likes of NASA. In addition, and ahead of the launch attempt, SpaceX President Gwynne Shotwell went on record as stating the launch wasn’t a “focus” for the company; that lay in upping the production rate for starship vehicles and boosters – a rather surprising statement, all things considered, and one I’ll return to later.

Launch came at 13:33 UTC, after some two hours of propellant loading on both vehicles, and proceeded per the notes below:

T -00:02: 33 Engine ignition and hold on the Orbital Launch Mount (OLM) as trust builds.
T +00:04 Launch clamps release, and vehicle commences ascent, most likely with the failure of three Raptors, two forming a pair on the outer ring of engines, one within the steerable inner ring.
T +00:11 Ship 24 clears the launch tower.
T +00:15 Booster 7 clears the launch tower, first confirmation of three engine failures / shut-downs.
T +00:19 Vehicle exhibits diagonal vertical movement, potentially due to the off-centre thrust resulting from the failure of the two outer ring motors.
T +00:28 Visible flashes in exhaust plume followed by debris departing the base of the vehicle at high speed – thought to be one of the hydraulic pressure units (HPUs), used to gimbal the inner ring of Raptor motors and steer the vehicle.
T +00:40 Loss of 4th Raptor, the third for the outer ring.
T +01:01 Loss of 5th Raptor, the fourth for the outer ring, as vehicle enters Max-Q.
T+01:30 Vehicle exits Max-Q.
T +02:00 Vehicle starts to exhibit off-nominal exhaust plume.
T +02:23 In a split-screen view, vehicle is seen to start slewing in flight at the point it is expected to rotate, re-stabilise and allow the separation of Ship 24 from Booster 7.
T +02:46 Vehicle is clearly spinning / tumbling.
T +03:09 Ship 24 appears to start venting propellants (or possibly a reaction / attitude control thrusters firing).
T +03:12 Venting (or thruster exhaust plumes) visible on both Ship 24 and upper portion of Booster 7.
T +03:25 Vehicle now clearly caught in a flat spin, venting / thruster plumes still visible from the booster’s upper section and from Ship 24.
T +03:58 Flight termination system (FTS) automatically triggered. Vehicle is destroyed.

While the data is still being assessed, the most probable cause for the loss of vehicle is a combination of the loss of at least one of the HPUs and the loss (or partial loss) of two of the inner gimbaling motors, coupled with the off-centre thrust generated by the failure of two pairs of motors located in the same hemisphere of the outer ring of 20 engines leaving the vehicle unable to sufficiently compensate for the biased thrust, resulting in the start of the spin / tumble, which continued beyond the point of recovery, triggering the FTS.

Following the launch, social media was swamped with hails of the launch being either a “success” or a “failure” – with the former being based on statements by SpaceX that if the stack cleared the tower it would be a “successful flight”; hardly the highest of bars to clear for a vehicle intended to be “rapidly reusable”, and the latter based on the fact that the vehicle had to be destroyed – also hardly a fair assessment: rocket can fail – as evidenced earlier in the month by the loss of the smaller Terran-1 rocket on its maiden launch.

Two views of Booster 7, showing 6 failed Raptor motors (l), and what appear to be two more in the process of shutting down (r). Credit: SpaceX

Certainly, there was a lot of valuable data gathered on the performance of the Raptor engines – although not all of this was good. From images gathered, it appears a total of 8 Raptors failed either fully (6) or partially (2). That’s a potential loss of 25% of thrust; not something you’d want to see on a payload carrying mission. On the other hand, however, the uncontrolled spin / tumble showed the starship / booster combination was fully capable of passing through Max-Q and showed remarkable resilience in withstanding any break-up prior to the FTS being triggered.

In particular, the test proved – as many looking at the launch site objectively had long noted (including myself) – the Orbital Launch Mount (OLM), the so-called “stage zero” of the system, was far from up to snuff if it is to support multiple launches, thanks to the lack of any provisioning of a water deluge system or flame deflectors.

Both of these are essential elements within any high-thrust rocket launch system. Flame deflectors do pretty much what their name implies: deflect the heat and flame of engine exhausts away from the launch complete infrastructure and launch vehicle, working in concert with the water deluge system. This delivers hundreds of thousands of litres of water across the launch pad and under it, to both absorb sound to prevent it being reflected back up onto the vehicle as damage-inducing pressure waves, and to absorb the raw heat of the engine exhausts through flash vaporisation – seen as the white clouds of “smoke” erupting from the pads during SLS and former space shuttle launches.

NASA’s Pad 39b water deluge system delivers 1.8 million litres of water to the mobile launch pad when in place over the flame trench, to help protect it and the rocket from sound damage, and into the flame trench itself (the “waterfall” in the image centre), to quench the heat and flame of the rocket engine exhausts, thus protecting the launch infrastructure (including the flame trench) from heat damage. Credit: NASA

Continue reading “Space Sunday: Starship orbital flight test”

Space Sunday: a bit of JUICE, a flight test & celebrating 50

An artist’s impression of the European Space Agency’s JUpiter ICy moon Explorer (JUICE). Credit: ESA

What is widely regarded as one of the most important space missions has been successfully launched to much acclaim and excitement.

No, I’m not talking about the SpaceX Starship / Super Heavy orbital test flight – of which more anon – but that of the European Space Agency’s JUpiter ICy moon Explorer (JUICE) spacecraft, a 1.6 billion Euro (US $1.7 billion) mission designed to gain a more thorough understanding of Jupiter’s three major icy moons – Europa, Ganymede and Callisto.

JUICE started life in 2008 as part of a joint NASA/ESA mission which had the rather clunky name of Europa Jupiter System Mission – Laplace (EJSM-Laplace), a US $4.7 billion mission to study Jupiter’s moons with a focus on Europa, Ganymede and on Jupiter’s magnetosphere. The mission would have comprised at least two independent elements, NASA’s Jupiter Europa Orbiter (JEO) and ESA’s Jupiter Ganymede Orbiter (JGO), with the potential for involvement on the part of Japan and Russia.

By 2011, it was clear to ESA that NASA would not have the budget to fulfil its part of the mission by the 2020s, and the JGO element morphed into JUICE, which was selected for the agency’s first L-class mission in May 2012, with ESA being proven correct in regards to NASA’s involvement in EJSM-Laplace in 2015, when the US agency reformulated its plans into the Europa Clipper mission.

JUICE was launched on 14 April 2023 at 12:14:36 UTC on the penultimate flight of an Ariane 6. The launch has been delays by 24 hours due to weather concerns, but on the 14th, the launch vehicle lifted-off smoothly, the satellite successfully separating from the rocket’s upper stage some 26 minutes after launch prior to commencing an internal systems check, after which it was due to ‘phone home and say, “Hi there!”

This call came a little later than the mission plan had estimated at some 40 minutes after launch, but still within the overall expected time frame. Following confirmation from ground control, the 6-tonne space vehicle deployed its 27-metre spans of solar arrays, completing the task a little ahead of schedule, reporting the arrays to be fully deployed and active.

The deployment marks the start of a complex 8-year coast to Jupiter which includes four gravity-assists from the inner planets to both boost the spacecraft’s velocity and to help swing it onto the required trajectory required for a successful Jupiter rendezvous (and a possible fly-by of the asteroid 223 Rosa in October 2029. These flybys will comprise:

  • August 2024 – a return to Earth, using both the Moon and Earth to accelerate and adjust course. This will be the most accurate gravity assist manoeuvre ever carried out by an interplanetary vehicle.
  • August 2025 – a flyby of Venus whilst travelling around the Sun, again accelerating the spacecraft whilst angling it onto a trajectory that will see it swing by Earth
  • September 2026 a second flyby of Earth (confusingly called “Earth flyby I”, which will throw it out into the solar system almost as far as Mars before it swings back around the Sun.
  • January 2029 – a third flyby of Earth (“Earth flyby II”) which will slingshot JUICE on a two year journey to Jupiter, with the possible asteroid flyby along the way.
An animation of the Earth / Venus flybys JUICE will perform, and its flight to Jupiter. Credit: Phoenix7777

On arrival in the Jovian system, in July 2031, JUICE will first perform a flyby of Ganymede in preparation for Jupiter orbital insertion about 7.5 hours later. This will place the vehicle in an elongated orbit around the planet, allowing it to perform some 35 flybys of the target Moons. The orbit around the planet will gradually becoming more circular over time, and will have an inclination that will allow JUICE to also study Jupiter’s Polar Regions and its magnetosphere.

The flybys will allow JUICE to observe its targets over a 3.5 year span of time, with a major focus on Europa. However, in December 2034, the focus of the mission will shift as JUICE enters an extended, 5,000 km elliptical orbit around Ganymede. This will be rapidly circularised to 500 km in 2035, allowing the vehicle to carry out an in-depth study of Ganymede’s composition and magnetosphere.

It is anticipated that the vehicle’s fuel reserves will be depleted to a point where accurate guidance and manoeuvring cannot be maintained by the end of 2035, and the last remaining reserves will be used to impact the craft on Ganymede at the end of that year or possibly very early in 2036.

The Ariane 5 rocket carrying JUICE lifts-off from Europe’s Spaceport in Kourou, French Guiana, April 14th, 2023. Credit: JODY AMIET/AFP

The primary aim of the mission is to more fully characterise the overall surface and (particularly) sub-surface conditions on (notably) Europa and Ganymede, and also on Callisto. As regulars to this column (and to space exploration in general) will know, Europa is believed to have a surface crust of ice covering what could well be a deep liquid water ocean, heated and kept in a liquid (or near-liquid) state by the moon being constantly “flexed” by the gravitational influences of the other Galilean moons as they orbit Jupiter, and Jupiter itself.

With this in mind, JUICE will specifically study Europa to understand the formation of surface features and the composition of the non-water-ice material. In particular, it will attempt to gather information on any chemistry essential to life which may be present on Europa’s surface, including organic molecules, and it will carry out the first sub-surface soundings of the moon in order to try to determine the thickness of the icy crust over the most recently active regions of the moon, and attempt to gain a clearer understanding of what lay beneath it – such as liquid water or icy slush.

While further away from Jupiter and with a more one-side “pull” being exerted on them, it is believed that both Ganymede and Callisto might also have oceans of liquid water (or perhaps icy slush) under their surfaces, so the main science objects for these moons – with the particular emphasis on Ganymede comprise:

  • Characterisation of the ocean layers and detection of putative subsurface water reservoirs.
  • Topographical, geological and compositional mapping of the surface.
  • Study of the physical properties of the icy crusts.
  • Characterisation of the internal mass distribution, dynamics and evolution of the interiors.
  • Investigation of Ganymede’s tenuous atmosphere.
  • Study of Ganymede’s intrinsic magnetic field and its interactions with the Jovian magnetosphere.

In all, the information gathered on the three moons should help scientists better assess their potential as havens of basic life within any warm oceans which may exist within them.

I think this is something that Europe can be extremely proud of. This is a mission that is answering questions of science that are burning to all of us.

– Josef Aschbacher, ESA Director General

The launch was the sixth Ariane 5 flight to carry an ESA mission, a total that includes the December 2021 launch of NASA’s James Webb Space Telescope that features significant ESA contributions. It was the 116th Ariane 5 launch overall, dating back to 1996. However, it was also the last flagship mission launch for the ESA workhorse; after an upcoming launch of two communications satellites, for the French and German governments respectively, Ariane 5 will make way for its Ariane 6 successor, with the first launch of the new rocket – which has had a troubled development cycle – is due towards the end of 2023 or early 2024.

Continue reading “Space Sunday: a bit of JUICE, a flight test & celebrating 50”

Space Sunday: Artemis, Starship and Stirling

The Artemis 2 crew: Christina Hammock Koch, Mission Pilot Victor Glover, Jeremy Hansen and, seated, centre Mission Commander Reid Wiseman. Credit: NASA

On Monday, March 4th, 2023, NASA announced the people selected to undertake the first crewed mission beyond the Earth’s orbit since Apollo 17 splashed down in the South Pacific Ocean on December 19th, 1972. The four individuals – three Americans and one Canadian  –  will undertake the first crewed flight of NASA’s Orion / Space Launch System (SLS) combination on an extended flight around the Earth and then out and around the Moon and back.

Along the way the Artemis 2 mission will tick of a number of firsts as it paves the way for the first of the planned Project Artemis missions to the surface of the Moon, which will commence with Artemis 3 in December 2025 / early 2026. For the crew, it will mark the first time a woman, a person of colour and a Canadian will fly beyond Earth’s orbit – and the mission will mark the Canadian’s first trip into space after a 14-year wait.

In announcing the crew, NASA Administrator Bill Nelson used words which echoed the words  (written by Ted Sorenson) spoken by John F. Kennedy in his September 12th, 1962 address at Rice University, Texas in which he rallied public support for the Apollo effort.

We choose to go to back to the Moon, and on to Mars. And we’re going to do it together, because in the 21st century, NASA explores the cosmos with international partners. We will unlock new knowledge and understanding. We’ve always dreamed about what more is ahead. Why? Because it’s in our DNA. It’s part of us. It’s who we are, as adventurers, as explorers, as frontiers people.

– NASA Administrator Bill Nelson, April 3rd, 2023

The four crew for the mission comprise:

  • Mission Commander Captain Reid Wiseman, USN. A US Naval aviator and test pilot born in Baltimore, Maryland, he was selected as an Astronaut Candidate in 2009 and flew in space on Soyuz TMA-13M, completing 165 days in orbit on the International Space Station as a part of the Expedition 40/41
  • Mission Pilot Captain Victor Glover, USN. Also a naval aviator, he was selected as an Astronaut Candidate in 2013, and flew the first operational flight of the SpaceX Crew Dragon to the ISS in 2020 as a part of the Expedition 64/65 crew. He was the first African-American to actually live and work on the ISS for an extended period (a total of 167days) rather than just visit it aboard the space shuttle.
  • Mission specialist Christina Koch. An engineer from Michigan, Koch is the most experienced of the crew, having already spent less than 30 days shy of a a year in orbit as a part of Expeditions 59/60/61 crews. Like Glover, she was selected for training in the NASA Astronaut Corps in 2013. However, prior to that, she was a graduate of the NASA Academy programme, and worked extensively on various space-related projects with NASA, the NOAA and various universities.
  • Canadian Jeremy Hansen, a colonel in the Canadian Air Force, is the the rookie of the crew – although he has extensive experience with NASA, the European Space Agency and the Canadian Space Agency. In 2013, Hansen served as cavenaut into the ESA CAVES training, and served as an aquanaut aboard the Aquarius underwater laboratory in 2014. His inclusion in the crew is in recognition o Canada’s longstanding support of, and partnership in, US space activities, which extends in the Project Artemis.

The four were initially selected by Joe Acaba, NASA’s Chief of the Astronaut Office, a role vacated by Wiseman so that he could have the opportunity to be selected for an Artemis mission. They were confirmed to the mission by NASA senior management, and the announcement featured a further Hollywood-trailer “trailer” video from NASA.

The flight itself is analogous to the Apollo 8 round-the-moon mission in 1968. Following launch, the Orion vehicle and crew will spend an extended period in Earth orbit, carrying out a series of vehicle checks and operational tests prior to making a free return around the Moon for a Pacific Ocean splash down after around a total of 10 days from launch. The mission will not launch earlier than November 2024.

Am I excited? Absolutely. But my real question is, are you excited? I see you and I ask that, because the one thing I’m most excited about is that we are going to carry your excitement, your aspirations, your dreams with us on this mission.

– Christina Koch

The three “driving principles” for Artemis 2 have been defined as: crew safety and survival; vehicle survival; and mission success. The mission success principle, the focus is on testing out the spacecraft subsystems, including in emergency and off-nominal conditions. There are additional flight test objectives the mission will attempt to carry out if time permits to help further reduce risk for later missions. One significant difference between Artemis 1 and Artemis 2 – outside of the latter carrying a crew – is that the Orion vehicle used for Artemis 1 was pushed to the limits, the vehicle going somewhat beyond the normal operations an Orion vehicle will experience during actual missions – the idea being to ensure the vehicle can survive the extreme end of its operational envelope.

The Artemis 2 mission – click for full size. Credit: NASA

With the announcement now out of the way, the Artemis 2 crew will commence formal training for the mission starting in June 2023 – the time between being given over to the four wrapping their other duties and work programmes so as to concentrate on the training and getting to know one another as crew and friends. Part of this training will extend to the famous WET-F tank at the Neutral Buoyancy Lab (NBL) in Houston, Texas.

This 12-metre deep pool is home to a full-scale mock-up of the external modules on the ISS, and is used to train astronauts for EVA work on the station’s exterior, and a part of which is being covered to offer a training environment to help crews train for the low-light conditions at the lunar south pole. It will be extensively used for the training of the Artemis 3 crew, but the Artemis 2 crew will help check the facilities out.

The core stage of the Space Launch System rocket that will launch the Artemis 2 mission. Credit: NASA/Michael DeMocker

More focused training will be on Orion operations, covering every aspect of the mission from pre-launch to post-splashdown and vehicle egress, together with a refinement of the overall mission parameters, spacecraft system performance checks, guidance system calibrations, etc.

SpaceX Re-Stacks Starhip as Expectations of a Launch Increase

SpaceX has completed re-stacking the first Starship / Super Heavy booster combination intended for launch, which has been taken by some to mean that the Federal Aviation Administration (FAA) is close to being ready to grant a launch licence for the attempt.

As I reported in my previous Space Sunday update, Booster 7 was returned to the orbital launch mount after both had undergone further upgrades. Following stacking, the booster went through a full propellant load test prior to Ship 24, the starship vehicle that will make the first sub-orbital launch attempt atop Booster 7, being returned to the orbital launch site at Boca Chica, Texas prior to being raised and stacked on the booster, allowing further propellant load tests to be carried out.

A Drone’s eye view of Booster 7 and Ship 24 stacked on the Orbital Launch Mounts at Starbase Boca Chica. Credit: SpaceX

Excitement over the launch grew when it was noted that the FAA issued maritime and air traffic advisories for April 10th covering both the Gulf of Mexico and Hawai’i, with back-up dates of April 11th and 12th. However, these were later revised for a potential launch date of April 17th – with the FAA noting that the inclusion of any dates in its advisories did not indicate that a launch licence had, or was about to be, granted.

Space journalist Eric Berger, taking to Twitter, further dampened expectations by pointing out it is possible the FAA might actually seek an injunction against any launch attempt pending SpaceX demonstrating it has taken the required steps to protect the surrounding wetlands environment from contaminated water run-off from the launch site – although he also noted that if there are no environmental objections, it is possible the FAA will grant a licence before month-end.

The first flight will see Booster 7 attempt to lift Ship 24 into a sub-orbital trajectory before it performs a burn-back and attempts a soft splashdown in the Gulf of Mexico. Ship 24. meanwhile will continue on in what appears to be a transatmospheric Earth orbit, meaning it will fly enough to test its thermal protection system through re-entry into the denser atmosphere, but without the need to re-ignite its engines to perform a de-orbit burn beforehand. Once within the atmosphere, the vehicle will attempt a powered soft splashdown off the coast of Hawai’i.

Overall, the flight realistically has less than a 50% chance of overall success given this is a first attempt to launch a recover a brand new orbital launch system. Even if the flight achieves all of its stated goals and both the booster and the starship survive, SpaceX have a long way to go before the system is shown to by either reliable or capable of meeting stated goals – something I hope to return to in a future Space Sunday special.

Continue reading “Space Sunday: Artemis, Starship and Stirling”