Tag: Astronomy

A potentially serious issue occurred at the International Space Station this week when Soyuz MS-22 developed a coolant leak in the early hours of Thursday, December 14th, almost 3 months after the vehicle had docked with the station to deliver Russian cosmonauts Sergey Prokopyev and Dmitry Petelin, together with American astronaut Francisco Rubio to commence a 6-month tour of duty.

Named for Konstantin Tsiolkovsky, the father of Russian cosmonautics, the vehicle experienced an uncontrolled leak of ammonia coolant which started at 00:45 UTC and ran for several hours, generating stream of material jetting outwards from the vehicle and causing the station crew to have to stabilise the structure.

At the time the leak was detected, cosmonauts Petelina and Prokopyev were preparing to embark on a spacewalk to carry out maintenance work on the Russian segment of the ISS, where the Soyuz is docked. The EVA was called off due to concerns the cosmonaut’s spacesuits could be contaminated with the hazardous coolant fluid.

A second Russian EVA set for December 21st was also later cancelled over concerns about the leak; however, NASA initially indicated a spacewalk due to talk place on the US / International side of the station would go ahead, later deciding to postpone it in favour of assisting Roscosmos in trying to assess the amount of damage caused to the Soyuz – and possibly to the ISS.

As the leak curtailed, cosmonaut Anna Kikina – the first Russian to fly to the ISS aboard an American commercial crew vehicle as a part of a seat exchange programme between NASA and Russian space agency Roscosmos – used a European-built robotic arm attached to the Russian Nauka science module delivered to the ISS in 2021 to inspect the Soyuz craft. Further inspections by both the Russians and Americas using their respective robot arms are also being scheduled.

The exact nature of the leak is unknown. However, the former head of spaceflight safety at the European Space Agency Tommaso Sgobba, believed the leak occurred with the vehicle’s active coolant system, most likely crippling it “beyond repair”. This appeared to be borne out both by the images captured by Kikina using the Nauka module’s robot arm – which shoe extensive damage to the outer skin of the instrument and assembly compartment of the vehicle. Since the leak, Roscosmos has reported the interior temperatures of the vehicle’s pressure modules had risen to 30C which, despite being referred to as being within “acceptable limits”

On Friday, December 16th, 2022, the Russian space agency began remote testing of a number of the vehicle’s systems – including its thrusters – in an attempt to ascertain its space-worthiness.

If the vehicle is unfit to fly, it means Prokopyev, Petelin and Rubio will be unable to use it to make their scheduled return to Earth in March 2023 – although reports that this leaves the three “stranded” in space are somewhat exaggerated. There are a number of ways in which the three can be returned to Earth either individually or collectively:

• Soyuz is fully capable of automated flight and docking with the ISS (it can use the same system as the Progress re-supply vehicles – themselves essentially uncrewed Soyuz – to reach the ISS and provide the three with a ride home.
• Failing this and allowing for the necessary crew alterations, both Soyuz and Crew Dragon can fly to the ISS with a vacant seat, which can then be used by one of the MS-22 crew.
• The Boeing CST-100 Starliner is due to make a crewed flight to the ISS in April / May 2023, a month or two after MS-22 is scheduled to return. It could, with some adjustment to the mission, be used to return one or two of the MS-22 crew as well as the main crew at the end of its week-long stay at the ISS.

Of these three options, the first would appear to be the most likely. For now however, assessments of MS-22’s overall condition are on-going and (for now) leave the door open on a fourth option: if the vehicle is deemed safe to make an immediate return to Earth, the three crew members curtail their mission and come home three months early.

The Artemis 1 mission to cislunar space is a potential watershed moment in space exploration., potentially the first genuine step in a human return to the Moon, with the potential to reach even further into the solar system. It’s a mission I covered in these pages over a number of articles, up to an including the previous piece. However, for those who would like to relive it in a compressed manner NASA has released a video of the mission’s highlight from launch to splash-down.

Running to 24 minutes – just shy of a total reflecting  the duration of the mission in days – the video is a fascinating compression of the mission, presenting many iconic images of the vehicle, the Moon and Earth.

Continue reading “Space Sunday: spaceship leaks, exo-Earths & an ancient solar observatory” →

NASA’s uncrewed Artemis 1 mission has started its return to Earth. Having reached the furthest distance on November 28th, the vehicle started back towards the Moon as it travels along its distant retrograde orbit (DRO).  Along the way it completed a further series of flight tests of both its manoeuvring systems and flights systems, including Callisto, NASA’s voice recognition software (based on Amazon Alexa) designed to assist crews during flight operations. On Wednesday, November 30th, the vehicle completed the first of three engine burns to start it on it way back to Earth. This was an “orbit maintenance burn” designed to maintain Orion’s trajectory as it headed back to the Moon, and to decrease its velocity, allowing the Moon’s gravity play a greater role in the craft’s trajectory. At 95 seconds, this burn ran for slightly longer than originally planned, allowing mission engineers gather  additional data to characterise the impact of the vehicle’s thrusters and their radiative heating on the spacecraft’s solar array wings to help inform Orion’s operational constraints.

On Thursday, December 1st, Orion completed the more critical DRO exit burn, slowing it further and “bending” its trajectory so it make a close passage around the Moon, bringing it to 127 km above the lunar surface, a point it will reach on Monday, December 5th.. At this point Orion’s service module will fire its main engine to exit lunar orbit to move into a trans-Earth Injection (TEI) flight path that will see it reach Earth on December 11th, when it will enter the atmosphere for a splashdown in the Pacific Ocean. As well as testing the flight system, NASA has used the flight back towards the Moon to capture further stunning images and video, with the agency also releasing a high-speed “mission highlights” video covering the mission’s launch and flight to the Moon and into DRO.

JWST and Keck Continue to Reveal Titan

In my previous Space Sunday update, I noted that the James Webb Space Telescope (JWST) has returned to full operations following the correction of an issue with its Mid-Infrared Instrument. The event was marked by the release of images captured by the instrument of Saturn’s largest moon, Titan. Since then, NASA, the space Telescope Science institute and the Keck observatory have released further stunning images of the moon, these taken with JWST’s Near Infrared Camera (NIRCam). In the first, two images of the moon are placed side-by-side captured using different filters. They reveal both the lower reaches of the moon’s methane-heavy atmosphere. The second reveals how NIRCam can look through the murk of such an atmosphere to see the surface of the moon. Both images reveal intriguing aspects of the moon.

On the first, NIRCam reveals two clouds, labelled “A” and “B”, whilst the second reveals some of the known surface details of the moon including Kraken Mare, believed to be a methane / hydrocarbon sea, and above which, intriguingly, “cloud A” had formed, suggesting it might be a weather system. Also imaged was Belet, a range of dark dunes and a bright albedo feature of uncertain nature, called Adiri. The clouds were of particular interest because they can validate long-held predictions from computer models about Titan’s climate: that clouds would form readily in the mid-northern hemisphere during its late summertime when the surface is warmed by the Sun. Further, observing how the clouds move or change shape might reveal information about the air flow in Titan’s atmosphere. To this end the JWST team observing Titan contacted colleagues at the Keck Observatory, Hawai’i who were about to start their own infra-red observations of Titan. They agreed to carry out a similar series of observations of the moon to allow for comparative science studies to be carried out.

The result is a series of images which appear to show the formation, movement and dissipation of the same cloud formations over the course of several days (November 4th-7th), offering the potential for those promised insights into climate and weather around Titan – although astronomers caution the clouds seen by Keck might be of different origin. NIRCam isn’t the only JWST instrument which gathered data on Titan during the observation period. The Near-Infrared Spectrograph (NIRSpec) examined the light reflected by Titan’s atmosphere to gather its spectra, which will allow scientists map what compounds are present in the lower atmosphere — including a strange bright spot over the moon’s South Pole, which has been a source of puzzlement for astronomers and planetary scientists.

China Sets a National Record for Taikonauts in Orbit

China had six tiakonauts in orbit for the first time this week as the crew of Shenzhou  15 joined their colleagues of the Shenzhou 14 mission aboard the nation’s new space station of a handover of station operations. Fei Junlong, Deng Qingming and Zhang Lu departed Earth on 29th November 2022 atop a Long March 2F rocket at around 15:08 UTC on November 29th. The vehicle docked with the forward docking port on Tiangong’s docking hub 6.5 hours later. Following the required post-docking checks, the hatches between station and vehicle were undogged and opened a 23:33 UTC,  allowing the Shenzhou 14 crew welcome their colleagues onto the station.

The new crew will be aboard the station for 6 months, and after their welcome and a rest period, they joined Shenzhou 14 team is preparing the station for their stay, carrying out a range of small but essential maintenance work using equipment flown to the station aboard the Tianzhou 5 resupply mission in November. With the hand-over work completed by Sunday December 4th, the Shenzhou 14 crew departed the station aboard their vehicle at 03:01 UTC. Once clear of the station, they performed a series of fast return de-orbit procedures, allowing them to soft-land within the Dongfeng landing area in the Gobi Desert in the Inner Mongolia Autonomous Region nine hours later at 12:00 noon UTC. Their return marked the most successful crewed mission to date for China, with 180 days spent in orbit, three spacewalks, a space lecture and overseeing multiple tests of the station, the arrival of both the the station’s science modules, the manoeuvring (and eventual undocking) of the Tinazhou 4 automated resupply vehicle and the arrival of Tianzhou 5.

The Shenzhou 15 crew are liable to be even busier. Among their tasks, they will be expected to carry out or monitor over 100 experiments both within the science modules and outside, across the six months of their stay. They will also be carrying out three or four EVAs (spacewalks) which will bring new challenges, including “parallel operations” each taikonaut outside the station working independently to the other, with the crew member aboard the station balancing the needs of both EVA crew. Then are scheduled to return to Earth in May 2023.

SpaceX Starship Update

On November 29th, SpaceX completed a second static fire test on its Super Heavy Booster 7, the booster earmarked to try to carry one of the company’s Staship vehicles to orbit – and once again things did not go as quite as planned. Lasting 13 seconds, the test was 3 seconds longer that the first static fire test, performed on November 14th, although it involved three fewer engines: 11 compared to the 14 used in the November 14th test. However, like the first test the firing resulted in damage to the orbital launch facility, gouging clunks of concrete from under the base of the launch table, hurling them into the air where they might strike the vehicle or the launch facilities.

As I noted following the November 14th test, the flying debris is the result of both an insufficient sound suppression system (SSS) and provision of a flame deflector. The former is best known for deluging a rocket launch platform with thousands of litres of water in order to absorb the sound of the rocket engines which might otherwise be deflected up against the rocket to damage it. However, it has an additional function: to “drown” the launch platform and the area beneath it to protect them from the searing blast of the engine exhausts at lift-off. The flame deflector performs a similar role in protecting launch facilities from rocket engines by deflecting the exhaust plumes out and away from the launch stand (and also carrying the excess water (and steam) from the SSS away from both the platform and rocket, further lessening the risk of damage to either. Part of the sound suppression system used by NASA for Space Launch System rockets is shown being tested in the video below. This element protect the concrete base on the launch facility, with water also being directed down the central flame deflector seen within the trench used to channel heat, steam and sound away from the launch platform. A second suppression system (not seen in this video) is built-in to the mobile launch platform itself, to give it the aforementioned protection from the heat of the SLS four main engines and two SRBs at launch.

However, SpaceX has thus far eschewed and flame deflector and has opted for a spray system of water and nitrogen gas delivered through pipes within the circular launch table on which the super Heavy / Starship combination sits. Already upgraded since its initial installation, this system appears adequate in terms of sound suppression, but does not properly protect the concrete apron directly below the rocket engines from their full fury. Whether this remains the case with all Starship / Super Heavy launch facilities remains to be seen:  this first orbital launch facility is very much a prototype. However, the lack of consideration for any form of flame deflection mirrors a similar decision not to initially equip the launch stand with another basic requirement of a launch facility: burn-off igniters which resulted in the July 11, 2022 spin-start test explosion under Booster 7. Following the November 29th test, two of the booster’s Raptor engines were swapped out at the pad, although it is unclear whether his was the result of damage from the materials flung upwards and outwards from the apron during the test or as a result off other motor issues. After this work had been completed, Booster 7 was disconnected from the launch platform and returned to the production area. This may again be to allow further damage inspections to be carried out, by is likely equally to allow the rest of the booster’s aft skirt to be fitted. At the same time as Booster 7 has been under test, Ship 24, which is due to be mated to it for the launch attempt, has been undergoing repairs at the sub-orbital launch platform where it has been completing its own series of static fire tests. The results of these tests appear to have been fed back into the assembly of Ships 25 and 26, the next vehicles in the series. SpaceX has indicated they are still planning a further 20-sec 33-engine Raptor static fire test prior to any launch attempt, which will also include a further autogenous repressurisation test (feeding cooled gasses from the engines back up into the propellant tanks to maintain their pressure as their contents are used). This coupled with the fact that the Federal Aviation Administration has yet to issue a launch license, means that the launch attempt is unlikely to come before 2023.

On November 16th, 2022 NASA launched what is – for a time at least – the world’s most powerful  rocket, the Space Launch System (SLS), on its maiden flight. The uncrewed mission marks the first flight of a human-capable vehicle to the vicinity of the Moon under the aegis of NASA’s Project Artemis.

Lift-off came at 06:47 UTC on the morning, and the rocket – roughly the size of the Apollo Saturn V but massing around 400 tonnes less and with engines generating 5 meganewtons greater thrust – was no slow climber like Saturn V; instead it fairly leapt into the night sky, thundering from 0 to 120 km/h in just a handful of seconds as it lifted an Orion capsule and service module away from the launch pad and on their way to orbit.

It was actually a launch that also nearly didn’t take place (again); during fuelling operations immediately ahead of the launch, a leak was detected. Such leaks have been the bane of this rocket’s existence, and for a time it was uncertain if NASA would stop or delay the fuelling operation – and even scrub the entire launch attempt.

Instead, a risky decision was taken to send in a Red Team to Pad 39B at Kennedy Space Centre to try to fix the leak with the liquid hydrogen propellant feed at the base of the rocket, even with propellants in the tank and the risk of a spark causing an explosion. The team – engineers Trent Annis, Billy Cairns and Chad Garrett worked under the “living” rocket – these monsters do not stand quietly when even partially fuelled, they creak, groan and periodically vent excess gasses – to tighten the “packing nuts” designed to hold the seals on the propellant feed line tightly in place. The crew arrived on the pad just 3.5 minutes ahead of the launch and had to work fast to fix the issue if a launch scrub was to be avoided.

Obviously, the team was successful – which does not lessen the risks they took as unsung heroes of the launch – and at 07:01 UTC, the Interim Cryogenic Propulsion Stage (ICPS) upper stage of the rocket placed the Orion vehicle in an initial orbit, and just over 30 minutes afterwards, the Orion service module successfully deployed the four solar arrays required to provide it and Orion with electrical power.

An hour later, after raising Orion’s orbit, the IPCS stage re-lit is engines to propel Orion from Earth orbit and into a trans-lunar injection orbit at 08:37 UTC, the stage separating from the space vehicle at 09:13 UTC.

Since then, the mission has progressed precisely as planned. At 14:30 UTC, Orion completed its first engine burn, correcting its flight to the Moon, and then late in the day a camera mounted on one of the service module’s solar panels captured a shot of Earth as seen from the vehicle, already almost some 92 thousand kilometres from Earth. On November 18th, the vehicle returned a further image of Earth – in greyscale – as it reached the 299,000 km from Earth mark.

The next major milestone for the flight comes on Monday, November 21st, 2022, Orion will complete the first stage of its leisurely, widely-curved outbound flight to the Moon. At 12:44 UTC on that day, with the vehicle passing around the far side of the Moon at a distance of 130 km, the vehicle will undertake a 2.5 minute burn of its main engine to direct itself into a distant retrograde orbit (DRO) which will carry it as far as 432,000 km from Earth.

The critical aspect of this manoeuvre is that it will occur when the vehicle is out-of-communication with Earth, thanks to the Moon being in between. The entire manoeuvre will therefore be carried out entirely by the onboard flight systems.

The flight so far has tested almost all of Orion’s flight, navigation and other systems, with only 13 issues, the majority defined as “benign”, being recorded. The most significant issue has been the star tracker – part of the flight navigation system. This was getting “dazzled” by thruster plumes as the vehicle adjusted its orientation during flight. While the tracker itself was designed to ignore the plumes, their brightness did confuse the flight software – something that hadn’t been considered could happen during testing. However, now it has been identified, the problem can be dealt with by Mission Control.

More substantial damage was actually done by the rocket itself at launch; the sheer power on the four RS25 engines and two solid rocket boosters did unspecified, but apparently extensive, damage to the mobile launch platform and launch tower. How much damage they sustained is unclear, but Pad 39B has been known to cause launch platforms using it damage. This was particularly noticeable following the launch of Apollo 10 in ay 1969 and again with the Ares 1-X launch in October2009 which resulted in some US $800 million in damages to the pad, platform and tower – although this was in part due  the vehicle having to be launched slightly off-vertical, resulting exhaust plume physically striking the tower.

As  I noted in my previous Space Sunday report, Orion is carrying a range of experiments onboard, all of which are being monitored throughout the flight. Chief among these are the radiation experiments which will come into their own as the vehicle enters its extended orbit around the Moon, where it will remain through until it again uses the Moon to swing itself back onto a return course to Earth in December 2022.

If you want to interactive track Artemis 1, you can do so via NASA’s Artemis Real-time Orbit Website (AROW). In the meantime, the video below captures the stacking of the Artemis 1 SLS vehicle inside the Vehicle Assembly Building at Kennedy Space Centre, together with the original roll-out to the pad earlier this year, and the night-time roll-out ahead of the launch, together with the initial phase of the mission’s ascent to orbit.

Continue reading “Space Sunday: Artemis rises, a star is (almost) born” →

Monday, September 26th 2022 will see NASA’s Double Asteroid Redirection Test (DART) reach its primary goal when a small space probe will collide with an asteroid called Dimorphos in an attempt to test a method of planetary defence against near-Earth objects (NEOs) by deflecting their path around the Sun via a kinetic impact.

The risk we face from Earth-crossing NEOs – asteroids and cometary’s fragments that routinely zoom across or graze the Earth’s orbit as they follow their own paths around the Sun – is not insignificant. More that 8,000 of such objects are currently being tracked, and that number is still rising. Such objects range in size from the relatively small to objects like the infamous 99942 Apophis (370m along one axis). which were it to strike Earth, would result in an estimated explosive force equivalent to 1,000 megatons, through to objects large enough to result in possible extinction events.

Over the years, various means of prevent such an impact have been suggested, with one of the most popular being the use of the kinetic energy from one or more impacts against the threat to alter its orbital track around the Sun so it would miss Earth. It is a popular option because if we get sufficient warning about a threatening object, it should be possible to plan an intercept mission to strike it at a point in its orbit where only a very small deflection in its track would be enough to ensure it misses Earth, allowing smaller, more manageable payloads to be used.

DART is the final incarnation of what started as two independent missions by NASA and the European Space Agency (ESA) to achieve the same goal. These were then combined into a single mission –  AIDA (for Asteroid Impact & Deflection Assessment(, which would have seen ESA launch a observation platform intended to fly to the designated target asteroid and carry out observations and analysis prior to NASA’s DART impactor arriving, and then observing the impact on the latter and the effect it had on the target’s orbit.

However, the ESA element of the mission was cancelled, leaving NASA to push ahead with DART, with the role of observing the impact taken over by Earth-based based observatories and a small payload carried by DART. To compensate, ESA now plans to launch Hera in October 2024, a mission and vehicle that will rendezvous with the target asteroid in 2027 to observe the overall results of the DART mission.

Dimorphos, the target for DART, is actually a relatively small asteroid, some 170m across (but still large enough to result in considerable destruction and loss of life were it to enter Earth’s atmosphere and explode). It has been selected for a combination of reasons, the most pertinent being it is actually the moon of a much larger asteroid, 65803 Didymos (Greek for “twin”), itself a NEO forming part of the Apollo group, and noted as being potentially hazardous to Earth. It is around 780m across, and it orbits the Sun every 770 days, its orbit eccentric enough  for it to cross both the orbits of Earth and Mars, and thus present a potential impact hazard to both.

Dimorphos (Greek: “having two forms” and discovered in 2003, seven years after Didymos was first located) occupies an equatorial and near-circular orbit around Didymos with a period of 11.9 hours. This makes it an attractive target because its position is easy to calculate / track, and the fact that it is orbiting a large object means that the angle of deflection as a result of DART’s impact can be directly measured against its motion around Didymos, and from this it will be possibly to extrapolate the amount of deflection achieved had Dimorphos been a solo asteroid en route to a collision with Earth.

DART launched on November 24th, 2021 atop a Falcon 9 rocket. In order to impact the asteroid at a speed sufficient to affect its velocity, the vehicle has been propelled towards its target by a solar-powered NEXT ion thruster, and will strike Dimorphos head-on at a speed of 6.6 kilometres per second. This should be sufficient to effectively slow it in its orbit around Didymos and result in a charge to the orbital period and shape. Given Dimorphos is large enough to exert some gravitational influence over its parent, it is expected that Didymos’ velocity and orbit will also be affected to a small degree.

Exactly how small or obvious all these changes will be is unknown – we simply do not know the topography of Dimorphos to know where and how DART will strike it. However, to assist with Earth-based observations of the impact, earlier this month DART released the Light Italian CubeSat for Imaging of Asteroids (LICIACube).

Built by the Italian Space Agency, this cubesat is now on a trajectory that will carry it through the Didymos / Dimorphos pairing, allowing it to observe and hopefully record DART’s impact and also gather initial data on the immediate results of the impact – although it is estimated that it will be a week or so before the overall effects of the impact can be properly interpreted. Similar cubesats, originally dubbed “Luke” and “Leia” but now officially called Milani and Juventas (a case of football winning out over Star Wars in the Italian science team?) will accompany the Hera mission in 2024.

DART itself carries little in the way of science instruments related to the mission, other than a 20 cm aperture camera called Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO, which should record and return images of both Didymos and Dimorphos right up to the actual impact). However, it is in many respects also a technology demonstrator, making use of the  Roll Out Solar Array (ROSA) system recently deployed to the International Space Station, and which allows for more efficient harvesting of sunlight over a smaller area of solar array surfaces to generate power, and also RLSA, the spiral Radial Line Slot Array, a new type of compact and lightweight high gain communication antenna.

Currently, DART remains on course for an impact with Dimorphos at 23:14 UTC on Monday, September 26th, 2022. The images returned by the DRACO camera ahead of the impact will mark only the 6th time we have received close-up images of the surface of an asteroid.

Big Boosters: SpaceX Booster 7’s Seven and Artemis 1’s Weather Delay

It’s been a week of ups and downs for the two big boosters which are most prominently on spaceflight enthusiasts’ minds.

At the SpaceX Starbase Facility in Boca Chica, Texas, Booster 7, the vehicle seen as the favourite to lift the company’s massive Starship into the sky on the system’s first orbital attempt, completed a second spin-start test of seven of its 33 Raptor 2 engines  on September 19th. This looked to be a different selection of motors to those tested the previous week, meaning that between 14 and 17 of the booster’s motors have now completed spin-starts. Nor was this the end of things: just a few hours after the spin-start – which lasted around 13 seconds – the booster was re-pressurised with fuel and warning given of a further engine test.

This was a full static fire of seven of the engines, marking the largest number of Raptor 2 motors to go through such a test thus far. Slow-motion payback of high-speed film shot of the event reveals that – as with the spin-start tests – rather than igniting all seven engines simultaneously, engine ignition was staggered, which might be indicative of how actual orbital launches will be managed; staggering engine starts by just a few milliseconds could help with reducing noise vibration resulting from all 33 engines coughing into life at the same time, and may even help reduce the amount of sound being deflected back up against the vehicle and the launch stand.

Following this test, SpaceX announced that, rather than remaining at the orbital launch facility for further engine tests, Booster 7 would be returned to the production centre at Starbase for “robustness upgrades”, and Booster 8 would replace it on the orbital launch mount to undergo its own testing. Whilst not entirely clear from the tweets given, it appears these tests will include a full wet dress rehearsal (WDR), which could involve stacking the booster with Starship 24, then fully tanking them and proceeding through a launch countdown that stops short of engine ignition. Then, after this, there will be a full 33-motor static fire test for a booster.

Whether this means Booster 8 will overtake Booster 7 to become the vehicle to make the first orbital launch attempt with a Starship on top, or whether the two boosters will again be swapped to allow Booster 7 make the attempt – which SpaceX appear to be hoping to make in November (still subject to the granting of an FAA license) – is unclear.

Either way, Booster 7 was removed from the launch mount mid-week, and the launch mount itself then went through a series of tests of its upgraded sound suppression system, which appears to deliver both water and nitrogen as to the flame pit of the launch table to both absorb sound (and reduce the potential for it causing damage to the vehicle or launch facilities) and reduce the risk of unexpected fire.

Meanwhile, on September 21st, NASA held a further fuelling test of the massive Space launch System rocket that will launch the uncrewed Artemis 1 mission to cislunar space. Earlier attempts to complete this test – a critical final step in readying the massive launcher for its maiden flight – had to be curtailed due to leaks in the liquid hydrogen fuel feed system at the base of the rocket, leading to padside repairs, as I noted in my previous Space Sunday update.

While the September 21st test also encountered leaks with the liquid hydrogen propellant flow, they were now sufficient to curtail operations, and the tst was successfully completed with both the core and upper stage liquid oxygen and liquid hydrogen tanks being fully fuelled roughly 6 hours after operations commenced.

One September 23rd, and after post-test checks on the vehicle, NASA held a press conference to confirm they would be making a launch attempt on Tuesday, September 27th, 2022 – only to have to call off the attempt on the 24th September due to tropical storm Ian threatening to roll across Florida and over the Space Coast, potentially requiring the vehicle to be rolled back to the safety of the Vehicle Assembly Building (VAB).

At the time of writing, no final decision had been announced regarding the roll-back proceeding. Should it occur, it is likely to occur overnight (local time) on Sunday 25th / Monday 26th September). This roll-back would mean the earliest launch opportunity would be October 2nd; however, this is a date in doubt due to the planned October 3rd launch for the NASA / SpaceX Crew 5 mission to the ISS from neighbouring Pad 39A. As both pads within launch Complex 39 at Kennedy Space Centre use the same infrastructure, back-to-back launches from the two pads are logistically difficult, and was there are further windows for the Artemis 1 launch, letting this slip is seen as preferrable to disrupting ISS operations.

The one good piece of news for Artemis 1, is that the flight termination system (FTS) has received a recertification waiver from the US Space Command at Cape Canaveral Space Centre. The FTS is used to destroy a rocket should it veer off-course post-launch. However, its batteries have a limited service life, and so packages need routine re-certification to state their batteries are suitable for use – or the batteries require replcing. Re-certification  / replacement means returning the vehicle to at VAB, further delaying any launch. However, the USSC has agreed that the package on the SLS could have the recertification delayed until mid-October, allowing the vehicle o be available for the late September / early October launch windows.

JWST Update: Images and Issues

On September 24th, NASA released images of the solar system’s outermost planet, as captured by the James Web Space Telescope. The pictures, taken in July 2022, show not only Neptune’s thin rings, but its faint dust bands, never before observed in the infrared, as well as seven of its 14 known moons.

Neptune has fascinated researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, it is characterised as an ice giant due to the chemical make-up of its interior, whilse because of the great amounts of methane and heavier elements within its atmosphere, it has a disntinctive ocean blue colouring when seen in visible light.

The JWST images capture Neptune in the near-infra-red wavelengths which are readily absorbed by the planet’s atmosphere. This results in it appearing very differently to how it appears in visible light, looking light a misty, crystal marble lit from within by bright streaks – actually the atmospheric interactions only previously hited at b the passge of high-althitude cloud zipping around the planet. Beyond it, and more particularly, the planet’s ring and dust system is revealed in the clearest detail seen in more than 30 years.

Among the seven moons also captured in the JWST images is massive Triton, which appears to float over Neptune like a giant star – the result of the moon reflecting around 70% of the sunlight striking it, thanks to the frozen sheen of condensed nitrogen covering it.

The images of Neptune came at a time when it was confirmed the observatory has developed a minor issue. This lays with a grating wheel mechanism within the Mid-Infrared Instrument (MIRI), resulting in suspension of one of the instrument’s four operating modes (medium-resolution spectroscopy observations).  The other three observing modes — imaging, low-resolution spectroscopy and coronagraphy — are not affected, and observations using those modes of MIRI are continuing.

The cause of the friction within the mechanism is not clear. Hoever, NASA made it clear the decision to suspend the affected operations with MIRI was not as a result of failure, but rather “an abundance of caution” so that engineers could review telemetry data from the instrument and the mechanism in order to understand the extent of the issue, what might be done to correct it and the potential for impact on mid-range spectroscopy data already gathered by the instrument. In the meantime, mission managers remain confident MIRI will return to full operations in the near future.

The launch of Artemis 1, provisionally scheduled for September 23rd has been … postponed,  just days after NASA indicated the date was their preferred new target for the uncrewed mission to cislunar space.

As I noted in my previous Space Sunday update, this date and the one following it (September 27th 2022), hinged on a number of factors, including a test of the repaired propellant feed lines on the mobile launch platform which have proven to be the thorn in NASA’s paw when it comes to the first launch of the massive Space Launch System rocket.

This test had been scheduled for Saturday, September 17th. However, it was decided to push it back to the 21st to allow more time for the ground crew to have more time to prepare for the load test. Attention has therefore switched to attempting the launch on September 27th with October 2nd a provisional back-up date. However, the latter remains under review as NASA plan to launch a crew to the International Space Station (ISS) aboard the SpaceX Crew 5 Falcon 9 / Crew Dragon combination from Pad 39A on October 3rd.

A further potential hurdle for meeting either launch date is the need for the US Space Force to grant a waiver on the recertification of the Flight Termination System (FTS) – the package used to remotely destroy the rocket if it veers off-course during its ascent through the atmosphere. The request for a waiver is still being evaluated at Canaveral Space Force station; if denied, then the rocket will have to be rolled back to the Vehicle Assembly Building (VAB) so the FTS can be fully re-certified – a porcess that is liable to push any launch back until after October 2nd.

The September 27th launch window opens at 15:37 UTC for 70 minutes and presents a “long class” mission for the uncrewed Orion space vehicle, lasting 41 days, with splashdown occurring on November 5th, off the coast of San Diego, California.

NASA Requests Proposals for Additional Lunar Landers

On September 16th, NASA issued a call for proposals for a lunar lander vehicle in support for crewed lunar missions beyond the initial Artemis 3 mission – the first mission to land an American crew on the Moon since 1972’s Apollo 17 mission.

That first mission is due to utilise a modified version of SpaceX’s Starship for place a crew of two on the surface of the Moon and return them to orbit. However, the contract granted to SpaceX – which has yet to actually proceed with work on the modified vehicle in earnest – was viewed as controversial at the time it was given, being granted in the face of two far more capable – if more expensive – proposals. As a result, NASA was ordered by Congress to seek an additional lander vehicle under what is referred to as the Sustaining Lunar Development (SLD) project. Companies interested in responding to the call have until November 15th, 2022 to do so.

The call is for a far more versatile vehicle than that defined by the contract for the initial Human Landing System (HLS) contract awarded to SpaceX. It calls for a lander vehicle type capable of “sortie” style missions with crews of 2 and landing up to 25 days apiece, with the crew living aboard the vehicle. These missions will likely be “scout missions” to evaluate potential sites on the Moon where a base might be established.

In addition, and supported by habitat units delivered separately to the lunar surface, the vehicle must be capable of landing crews of 4 astronauts on the Moon for up to 33 days at a time. Finally the vehicle design must be capable of automated cargo landings on the Moon in support of crewed missions.

It is not currently clear whether the two completing proposals for the original HLS contract – led respectively by Blue Origin and Dynetics – will participate in submitting proposals. Two of Blue Origin’s partners for the original HLS contract, Lockheed Martin and Northrop Grumman, have remained non-committal towards further participation in any additional lander projects since the SLD project was formally announced in March 2022.

Dynetics, however, were one of five companies to receive US $40.8 million each from NASA as a part of a 15-month initial SLD study initated in September 2021. As  a part of this work, Dynetics committed to risk-reduction activities and provide feedback on NASA’s requirements to cultivate industry capabilities for crewed lunar landing missions. Of the three original HLS  proposals, the Dynetics design – whilst the most expensive – most closely matched the requirements outlined in the SLD call and offered the advantage of being launched to the Moon using vehicles other than SLS. As such, there is some speculation they will respond to this new call for proposals.

SpaceX is excluded from responding to this new call for proposal. However, NASA indicating it plans to exercise an option in SpaceX’s existing contract and call on SpaceX to evolve is lunar Starship design “to meet an extended set of requirements for sustaining missions at the moon and conduct another crewed demonstration landing.”

Continue reading “Space Sunday: the Sun, Moon and updates” →