Category: Space Sunday

Update: October 6th: Two hours after this article was published, NASA announced launch operations for the Europa Clipper mission are standing down, and the launch postponed due to Hurricane Milton. A new target launch data will be announced once the hurricane has cleared the Florida Space Coast and any damage to facilities at Cape Canaveral Space Force Station’s SLC-41 launch pad assessed.

If all goes according to plan, October 10th should see the launch of the second of NASA’s Large Strategic Science Missions of the 21^st century (formerly called Flagship missions, and the first having been the James Webb Space Telescope): Europa Clipper.

The launch will see a SpaceX Falcon Heavy carry a NASA space probe bearing the same name as the mission on the first leg of a 5.5 year journey to Jupiter to study the Galilean moon of Europa. In order to achieve this goal, the spacecraft will be directed towards Mars, which it will reach in February 2025. Using the Martian gravity as a brake, the spacecraft will fall back toward the Sun and encounter Earth again in December 2026, using our planet’s gravity to fling it out on a trajectory to reach Jupiter in April 2030.

On arrival at Jupiter, the vehicle will enter an initial orbit that will then be refined, allowing it to make some 44 fly-bys of Europa varying between just 25 km above the surface and 2,700 km. The reason fly-bys will be made rather than the craft entering orbit around Europa directly is large due to radiation. Europa lies well within Jupiter’s extreme and intense radiation belts, an environment so harsh that it would fry the spacecraft’s electronics and electrical component – notably the huge solar arrays which generate its power – in just a few months after its arrival.

In addition, the spacecraft is carrying a significant science payload which can gather data much faster than the communications system can transmit it to Earth; were it to be placed in orbit around Europa, the opportunities to transmit the data its has would be subject to a a range of limitations (such a when Jupiter is between the probe and Earth), risking data loss due to existing data being overwritten before it could be transmitted.

By taking up an orbit around Jupiter and simply swinging by Europa, the space craft may lose opportunities for gathering data, but it increases the time available for the successful transmission of the data it does collect safely. Rather than having mere minutes or hours in which to send information, the probe will have between 7 and 10 days at a time. Further, by orbiting Jupiter rather than Europa, the spacecraft “dips” in and out of the harshest radiation, rather than being subjected to it all the time,  thus preserving its electronics for much longer, and allowing it a primary science mission of an initial 3.5 years.

To assist it whilst orbiting Jupiter, Europa Clipper will use 24 thrusters connected to a hypergolic propulsion system with 2.7 tonnes of propellants. Up to 60% of this mass will be used during the initial orbital insertion phase around Jupiter in April 2030, with the rest used in stabilising the spacecraft and orienting it during Europa fly-bys and communication periods with Earth to maximise data gathering and transmission.

The suite of nine instruments on the vehicle will be used to study Europa’s interior and ocean, geology, chemistry, and habitability. The science payload accounts for some 82 kg of the vehicle’s mass and includes a pair of imaging cameras operating in visible light wavelengths, and both a thermal imaging system and a near-infrared imaging system which will search for the likes of dynamic activity on the icy-covered surface of Europa (e.g. vents venting water and sub-surface material into space) and the distribution of organic material across the moon’s surface.

The vehicle also carries an instrument called REASON – the Radar for Europa Assessment and Sounding: Ocean to Near-surface (NASA still reign supreme in the acronym stakes!) – an ice-penetrating radar designed to characterise the 10-30 km (estimated) thick ice crust of the moon, seeking information on its composition and any indications of water pockets within it, any exosphere existing just above it as a result of venting, and – hopefully – reveal something of the nature of the upper limits of the liquid water ocean sitting under the lowest extent of the ice, between it and Europa’s rocky mantle.

Whilst it has launched some 18 months after ESA’s JuICE (Jupiter Icy Moons Explorer – see: Space Sunday: a bit of JUICE, a flight test & celebrating 50) mission, Europa Clipper will arrive in Jupiter orbit more than a year ahead of it by virtue of being launched atop a more powerful launch vehicle. In doing so, it will take over from the Juno mission as NASA’s lone research spacecraft orbiting Jupiter (the Juno mission is expected to come to an end in September 2025, the vehicle having exhausted the vast majority of its propellants, leaving only sufficient for it to make a controlled entry into Jupiter’s upper atmosphere and burn-up).

During its fly-bys of Jupiter, the Juno spacecraft has also been able to study the Galilean moons as well, and while the mission’s overall science goals have been very different to those of the Europa Clipper and JuICE missions, they are nevertheless somewhat foundational, helping both NASA and ESA better understand the environment in preparation for JuICE and Europa Clipper. Once both craft are in orbit around Jupiter, the respective science teams will work closely together, JuICE being tasked with studying Europa as well as the other two potentially water-bearing moons of Jupiter, Ganymede and Callisto.

In all, should the October 10th launch opportunity be missed (e.g. due to weather), the Europa Clipper launch window will remain open for a further 20 days.

Vulcan Triumphs despite SRB Anomaly

United Launch Alliance (ULA) completed the second launch of its new Vulcan Centaur rocket on Friday, October 4th, and despite a significant issue with one of its Northrop Grumman GEM-63XL solid rocket boosters (SRBs), the vehicle went on to ace the flight.

Vulcan Centaur is a ULA’s replacement for both the veritable Atlas and Delta families of launchers, and like them it is currently fully expendable. I covered its successful maiden flight for the vehicle, sending the ill-fated private lunar lander Peregrine One by in January 2024 (see: Space Sunday: lunar losses and delays; strings and rings). Following that flight, ULA had hoped to launch Vulcan again in April 2024, carrying aloft Tenacity the first of the Dream Chaser cargo space planes being developed by Sierra Space; however, delays with Tenacity’s final preparations now means this launch has been pushed back until at least March 2025. Instead, ULA decided to go ahead with flight designed to certify it for DoD launches, using a payload mass simulator in place of an actual payload.

Launch came at 11:25 UTC on October 4th, the vehicle lifting-off from Launch Complex 41 (SLC-41) at Cape Canaveral Space Force Station in after around a 30-minute delay. After clearing the tower, it became obvious that the right-side GEM-63XL booster was suffering an anomaly: the exhaust plume was broader than it should have been and it appeared that ignited propellants might have been escaping the SRB just above the engine bell.  Then, roughly 37 seconds into the launch as the vehicle was about to commence its roll programme to pitch itself out over the Atlantic, and just before passing through clouds, the base of the right-side SRB disintegrated.

On emerging from the cloud, cameras revealed the damaged SRB now had a very “off-nominal” exhaust plume, with pieces falling away as the launch vehicle continued its ascent. And here is where the overall robustness of the GEM-63XL came into play and the superb flight avionics and capabilities of the Vulcan Centaur were demonstrated. Rather than simply unzipping and exploding, taking out the entire rocket, as might reasonably be expected with the rocket was entering and passing through “max Q”, the period when it faces the maximum dynamic stresses imposed on its structure during ascent, the GEM-63XL held together and continued to provide at least some semblance of thrust all the way up to the engine cut-off point.

Meanwhile, the Vulcan Centaur sense the asymmetric thrust pushing it off of its flight trajectory and commenced compensating for it by gimballing the two Blue Origin BE-4 engines of the first stage and adjusting their thrust. At the same time, the vehicle started looking downrange and recalculating flight parameters in order to achieve a successful orbital insertion for its upper stage and payload. This entirely automated response also included calculating the likely drop-zone for the two SRBs following separation as a result of the off-nominal performance of the right side SRB.

This actually resulted in the rocket “holding on” to the two SRBs for 20 seconds beyond their expected release time. In doing so, this pretty much ensured both SRBs had sufficient upward momentum to complete their ballistic trajectory and then fall back to the Atlantic Ocean without exceeding any downrange parameters. Similarly, the rocket performed a recalculation of the required burn time on its main engines, and for the same reason.

Thus, the two BE-2 motors ran for an additional 6-7 seconds beyond their designated cut-off time. This was enough to ensure the Centaur upper stage received the kick it needed and the first stage to also remain within the parameters of its specified descent trajectory into its targeted (and shipping-free) splashdown area. Once separated, the Centaur stage was able to light its motor and go on to deliver its mass simulator almost exactly in the centre of the “bull’s-eye” of its intended orbital track.

And that is a remarkable success, all things considered. Sadly it did not stop some SpaceX cultists proclaiming FAA “bias” against SpaceX because a) Vulcan has not been “grounded” following the “failure” and b) the FAA signalled no requirement for a Mishap investigation on the grounds that, despite the SRB issue, the vehicle performed precisely as called for within its flight plan, and at no time exceeded the limits of it launch license.

Obviously, the GM-63XL failure needs to be thoroughly investigated by Northrop Grumman (potentially with FAA oversight) and the causes understood together with any significant issues – if found – rectified.  However, this in itself require a “grounding” of Vulcan Centaur nor does it illustrate any kind of “bias” towards SpaceX on the part of the FAA. Why? Firstly, because the conflict between SpaceX and the FAA relate pretty much to the later exceeding the limitations imposed in the launch licenses issued to it by the latter. That’s not the case with the Vulcan Centaur flight.

More to the point, Vulcan Centaur’s launch cadence is fairly relaxed; the next launch will not occur until mid-November, for example. Ergo, there is more than enough time for the SRB issue to be investigated and a decision taken as to whether there is any kind of fault endemic to the GEM-63XL which precludes further Vulcan Centaur launches until such time as the problem has been rectified, and without the need for the FAA weigh-in on the matter pre-emptively.

Voyager 2 Loses Further Science Instrument

The two Voyager mission spacecraft have been hurling themselves away from Earth since their launches in 1977. In doing so, they are the first human-made craft to reach interstellar space, and are truly voyaging into the unknown. But even though both are powered by three radioisotope thermoelectric generators (RTGs) – essentially “nuclear batteries” generating electricity through the decay of plutonium 238 – their ability to produce the electricity they need to operate is constantly declining.

At launch the three RTGs on each of the Voyager vehicles generated some 470 watts of electrical power on a continuous basis. However, by 2011, that had been reduced to just 268 watts per vehicle. To combat the loss of electricity production NASA has, since 1998, been gradually turning off systems and instruments that are no longer essential to either vehicle’s mission.

For example, in 1998, NASA turned off the imaging system on the two spacecraft because the amount of light reaching them was insufficient for them to be able to produce meaningful images. Over time, this policy has continued to the point were, at the start of October 2024, of the 11 instruments aboard each of the vehicles, Voyager 1 had just four operating and Voyager 2 had just five, all dedicated to examining the interstellar space through which both vehicles are travelling.

However, on October 2nd, 2024, NASA announced that a further instrument on Voyager 2, the Plasma Spectrometer, has now been turned off, again to meet the dwindling amount of energy the RTGs are producing. This means that both craft are now operating the same four instruments each, allowing for solid comparative science to be carried out as they continue to move out into interstellar space. These instrument comprise a magnetometer gathering data on the interplanetary magnetic field; a low energy charged particle instrument for measuring the distributions of ions and electrons in the interstellar medium; a cosmic ray system that determines the origin of interstellar cosmic rays; and a plasma wave detector.

Unfortunately, overall power issues mean that the rate at which instruments must be turned off is likely to accelerate over the next few years, and that by 2030 it is likely the last science instrument on both Voyagers will be turned off, although there may be sufficient power for the communications systems to continue to transmit system reports beyond that, if NASA opt to allow them. But even if this is the case, by 2036, the signals from the two spacecraft will be so weak, they will not be heard by facilities on Earth.

But the loss of communications, when it eventually comes, will not be the end of the voyage for either of the spacecraft: in 300 years they should reach the “inner edge” of the theorised Oort cloud. It will take each of them some 30,000 years to cross it and arrive at the cosmographic boundary of the solar system. Ten thousand years after that, Voyager 2 will pass “just” 1.7 light-years away from the first star relatively close to its trajectory since departing the Sun: Ross 248. At roughly the same time, Voyager 1 will pass within 1.6 light-years of the star Gliese 445.

If you want to keep abreast of the Voyager mission status then check the official “where are they now” page for the mission.

After delays related to a ground-side helium leak at the launch pad followed by a prediction of several days of poor weather in the region where the mission would splashdown at its conclusion, thus potentially hampering recovery operations if not put the crew and vehicle at outright risk, the Polaris Dawn private venture mission lifted-off from Kennedy Space Centre, Florida on September 10th, 2024.

The Falcon 9 rocket carrying Crew Dragon Resilience and its crew of four private citizens lead by billionaire Jared Isaacman,  departed Launch Complex 39-A at 09:23 UTC at the start of an extreme 5-day mission in an extended elliptical orbit around the Earth with a number of potentially high-stakes goals, including the very first spacewalk by non-career astronauts.

The first part of the mission called for the capsule to be placed in an orbit of around 200km perigee and an apogee of 1,200 km. This required the first stage of the Falcon 9 booster to operate in expendable mode, running for some 12 minutes prior to separation, after which it fell back into the Atlantic Ocean. On arrival in their initial orbit, the crew commenced an extended period of pre-breathing an oxygen-rich atmospheric mix designed to remove nitrogen from their blood, organs and muscles.

Such pre-breathing (very similar in nature to that undertaken by divers going down to significant depths in the oceans) is a requirement of all EVA work, as space suits operate at very low pressures (e.g. roughly 5 psi compared to the average sea-level atmospheric pressure of 14.8 psi). If the nitrogen is not flushed from the body, it can bubble and cause decompression sickness, causing serious injury –and potentially death – to the sufferer as the pressure is raised back to normal levels.

Normally, such pre-breathing would be carried out only be the astronauts making the EVA, and they would use an airlock in which to do so, spending several hours undergoing the process. However, Crew Dragon does not have any form of airlock, so the entire vehicle must be depressurised, hence the entire crew going on the oxygen rich mix. As this happened, work also started on very slowly reducing the overall cabin pressure from 14.5 psi to 8.6 psi, a process that continued over the first three days of the mission leading up to the actual EVA.

After some eight orbits around the Earth, the Dragon’s motors fired, elevating its apogee to around 1,400 km above sea level. This marked the furthest anyone has been from Earth since Apollo 17 in 1972, whilst also breaking the highest altitude record for a crewed mission orbiting Earth, originally set by Gemini 11 in 1966.

Both the 1200 and 1400km limits of the orbit meant the vehicle would skirt the Van Allen radiation belts, periodically passing through the South Atlantic Anomaly. This meant that during their five days in space, all four crew would be exposed to the same amount of radiation an astronaut on the International Space Station (ISS – orbiting at an average of some 400 km) would require some three or more months to experience. Whilst such a concentrated exposure marked a great long-term risk to the health of the four, it formed part of the science programme for the mission.

In brief, radiation exposures as a fact of space travel, but despite all the work aboard the ISS and other orbital vehicles like the space shuttle on extended missions, there are numerous active factors of radiation exposure in space that are not clearly understood. To this end, Polaris Dawn flew a series of experiments put together by Translational Research Institute for Health (TRISH), a NASA-funded consortium of academic institutions specifically aimed at investigating some of the more usual aspects of space-based radiation exposure, in order to better understand them.

Polaris Dawn crewmembers participating in these TRISH studies will provide data about how spaceflight affects mental and physical health through a rigorous set of medical tests and scans completed before, after, and during the mission. The work will include assessments of behaviour, sleep, bone density, eye health, cognitive function and other factors, as well as analysis of blood, urine and respiration.

– NASA statement on the Polaris Dawn NASA-sponsored science

Much of this work will continue well after the mission’s conclusion, with studies and checks on their health and welfare continuing over the next few years.

In addition, the mission flew Tempus Pro, a commercial package NASA has been adapting for use on space missions. It is designed to collect collect multiple health measurements from astronauts and compare them with a database of medical data on Earth, allowing flight surgeons to more fully diagnose an astronaut’s overall physical and mental health and well-being. The system can also be used to provide real-time telemedicine support (including any consultations from specialist almost anywhere on Earth) to assist medical personnel on space missions in provide physical and mental treatment to their fellow crewmembers.

In all the mission carried a total of 36 experiments from 31 partner institutions around the world. However, it was the EVA – to be undertaken in turn by Isaacman as crew commander (and major financier, who originally flew the Inspiration4 private venture orbital flight in 2021, and which also utilised Crew Dragon capsule Resilience), and Sarah Gillis, the senior space operations engineer at SpaceX – which had captured the attention of the world ahead of the mission.

The EVA took place on Flight Day 3, after the vehicle’s orbit haf been lowered and circularised at some 730 km above sea level. It commenced some time in advance of the actual hatch opening, with a further round of pre-breathing a 100% oxygen atmosphere to purge remaining nitrogen from the astronauts’ bodies, and a slow final lowering of the cabin pressure prior to full  venting.  All four then donned their IVA / EVA suits and tested their umbilical life support and power feeds (the SpaceX suits do not operate with the kind of back-pack common to NASA / Roscosmos EVA suits, but are reliant on a physical connection to the space vehicle).

At 15:12 UTC on Thursday September 12th, 2024, all four crew reported their suits were sealed and operational, and they were operating entirely off of the life support reserves supplied to their suits. The final de-pressurisation of the capsule cabin could then commence, causing their suits to expand to their pressurised size. Some 37 minutes after final depressurisation had  started, the vehicle was ready for the inner hatch to be unlatched by Isaacman, as EVA-1, and the pressure seal broken. This then allowed the hatch opening mechanism to be triggered, with the hatch sliding fully open at 15:56 UTC.

Isaacman then egressed through the nose chamber onto the “skywalker”, a special ladder-come-work platform with hand holds and foot restraints, design to allow a crew member to both raise themselves out of the nose of the craft and anchor their feet on the platform so that they can perform hands-free work.

A camera mounted on Resilience’s nose cone cap (which had been opened as per standard practice since the craft’s arrival in orbit to help with general heat regulation) filmed Isaacman as he emerged from the nose of the vehicle, initially rising to waist level before carrying out a range of mobility tests as the spacecraft raced over Australia and towards New Zealand and the terminator between the day and night sides of Earth.

The mobility tests were designed to test both ease and range of movement within a pressurised IVA / EVA suit, both with arms and legs, moving up and down the steps on the “skywalker”, testing the ease of use of the foot restraints, and the overall freedom of movement and reach allowed by the suits when in the near-vacuum of space. In all, Isaacman spent roughly 8 minutes on the platform before climbing back down into the capsule.

Sarah Gillis then replaced him, moving into the nose of the capsule and onto the “skywalker”. Unfortunately, shortly after she anchored herself on the “skywalker” to commence her own series of tests, Resilience passed out of video relay range of NASA Tracking and Data Relay Satellite System (TDRSS), so the live video feed was lost, leaving only verbal communications. However, she spent almost the same amount of time as Isaacman in her EVA, allowing her to give an engineer’s perspective on the usability of the suits.

By 16:21 UTC, Gillis was back inside Resilience and the inner hatch was closed, leaving Isaacman with the task of latching and locking it securely. Over the next 50 minutes, the pressure inside the vehicle was restored to a point where the crew could use the cabin’s atmosphere and start removing their IVA / EVA suits.

The EVA by the numbers (from space commentator Jonathan McDowell:

• Total elapsed time (starting when the capsule was fully depressurised through to being re-pressurised to approx 5 psi): 1 hour 46 minutes.
• Total “spacewalk time” (time from unlatching the inner hatch to re-latching it): 33 min 25 seconds.
• Total time Isaacman spent on the “skywalker” and outside the cabin: 7 minutes 56 minutes.
• Total time Gillis spent on the “skywalker” and outside the cabin: 7 minutes 15 seconds.

These may not be record-breaking numbers, but they are nevertheless extraordinary and of potential significance as a starting-point for such operations by non-career astronauts. Private venture EVA operations are bound to become more and more commonplace and of longer and more complex duration as the next generation of private / commercial orbital facilities by the likes of Axiom and the Blue Origin / Sierra Space led Orbital Reef consortium come on-stream.

The remaining two days of the mission saw the four astronauts resume their science work as cabin pressure within the vehicle was gradually brought back up to more reasonable pressures in advance of a return to Earth. As well as the science work, the crew also conducted tests in using the SpaceX Starlink satellite network for audio and video communications with mission control.

Part of the latter once again involved Sarah Gillis, who is also a classically-trained violinist. On September 13th, she performed of Rey’s Theme by legendary composer John Williams. Whilst the performance was misreported in some media as the “first” performance of a musical instrument in space (instruments have been played in space for decades; for example, Catherine Coleman played the flute on the ISS in 2011 and Chris Hadfield, commander of ISS Expedition 35  famously recorded a music video of David Bowie’s Space Oddity, marking it as the first music video ever shot in space), it was nevertheless still and important factor for the mission’s overall objectives.

One of the things Isaacman has done with her personal fortune and through his private space ventures is to raise money St. Jude Children’s Research Hospital in Memphis, Tennessee. In 2021, for example he both donated several million to the hospital and auctioned off seats on the Inspiration4 mission with the money raised going to the hospital.  Gillis’ rendition of Rey’s Theme was combined with six orchestras from around the world to produce a recording and video entitled Harmony of Resilience to help raise further funds for the hospital from this mission.

As we travel around our beautiful planet Earth on this five-day mission, we wanted to share this special musical moment with you. Bringing together global talent, this performance symbolizes unity and hope, highlighting the resilience and potential of children everywhere.

– Sarah Gillis, September 13th, 2024, from orbit aboard SpaceX Crew Dragon Resilience

Polaris Dawn ended on Sunday, September 15th, 2024, with de-orbit operations starting at 06:34 UTC. These saw Resilience orient itself ready for atmospheric interface and jettison its service module – the Trunk, in SpaceX parlance to expose its heat shield. A series of thruster firings of the capsule’s Draco motors followed, slowing it velocity. These were completed by 06:50 UTC and the forward nose cone was swung back into its closed positions and latched.

At 07:15 UTC, the vehicle reached interface and entered a roughly 7-minute period of descent through the upper atmosphere during which the vehicle experience peak frictional heating around it, together with a loss of communications. The track of Resilience meant it was not only caught on camera by recovery vessels in the Gulf of Mexico, but also seen by the crew of the ISS.

Things then proceeded rapidly. After re-entry, the vehicle’s drogue parachutes deployed so start slowing it, and not long afterwards, the four large main parachutes deployed, with Resilience splashing down at 07:37 UTC.

An initial safety and recovery team approached the capsule in a RHIB deployed by the SpaceX recovery vessel Bob (named for astronaut Bob Behnken, one of the first two people to fly a Crew Dragon to space (the other being Doug Hurley, who has the larger recovery ship Doug named for him) to confirm the capsule was safe and not venting harmful gasses. At the same time, additional RHIBs sought to recover the spacecraft’s parachutes.

With the confirmation all was safe, the recovery operation began, the RHIB team preparing Resilience for hoisting onto Bob’s stern deck as the recovery vessel slowly closed with the capsule to arrive alongside at 08:00 UTC. Eight minutes later, with the lifting lines secured, the loading arm at the stern of Bob raised the capsule up onto the ship’s deck, where it was moved forward to the egress platform under the cover of the ship’s helipad and at a height that allows for easier opening of the capsule’s hatch.

The latter was opened at 08:20 UTC, after a final round of checks, and the recovery ship’s surgeon entered the capsule to check on the overall condition of all four crew to ensure they were showing no signs of decompression sickness or other issues. After this, the crew were allowed to exit the vehicle, with SpaceX lead space operations and mission director Anna Menon the first to leave the capsule, followed by Sarah Gillis then pilot Scott Poteet and finally Isaacman. All were in a jubilant frame of mind – and rightly so.

Polaris Dawn was in many respects a high-stakes mission; Resilience had to be extensively modified for the flight – not just her forward nose area, but throughout, with electronics and other systems inside the vehicle being “hardened” for us in the near-vacuum of Earth orbit; the IVA / EVA suit, despite extensive testing on Earth was still unknown in terms of how it would work in space, and the crew themselves took on a lot in respect of future health and welfare through such an intense exposure to Earth’s radiation fields over so limited a time. In this latter aspect, the mission’s work will continue through post-flight research, as noted above.

Two more Polaris missions are in development, although their time frames and goals have yet to be confirmed. One will most likely involve another Crew Dragon flight, and Isaacman has stated he plans the third to be the first crewed flight of SpaceX’s Starship vehicle; so that one at least is unlikely to be in the immediate (and potentially foreseeable) future.

Boeing’s Starliner capsule Calypso is back on Earth after what appears to have been an almost pitch-perfect automated return flight form the International Space Station (ISS).

The vehicle departed the ISS at 22:04 UTC on September 6th, after almost a day of preparations during which Starliner’s inner hatches were sealed as was the hatch on the ISS’s Harmony docking adaptor, prior to the “vestibule” at the forward end of Calypso, containing the vehicle’s half of the docking mechanism, being slowly depressurised. Some time prior to the undocking, and while awaiting the formal ATP – authority to proceed – the two control rooms at Johnson space Centre, Texas, one for the ISS the other for Starliner, did a final go / no-go poll, after which ISS Flight Director Chloe Mehring called the station.

Station Houston space-to-ground 2 for Starliner undock.

Go ahead, we’re with ya.

Hey, Suni both the Starliner and the ISS flight control teams have polled GO for undock at this time. Expected undock time is 22:04 [UTC].

Okay, copy. 22:04. Hey, y’know, just looking at the flight control roster, and like wow! It is the all-star team! You guys, it IS time to bring Calypso home. You have GOT this! We have your backs, and you’ve got this. Bring her back to Earth.

– Exchange between Flight Director  Chloe Mehring and astronaut Suni Williams on the ISS prior to Starliner’s departure.

ATP came at 22:02 UTC, and the 12 docking “hooks” on the ISS docking adaptor rotated to their “open” position, allowing springs on the Starliner’s docking mechanism to very gently push it away from the space station two minutes later. The use of such springs avoids the need for the vehicle to use its forward thrusters, potentially spraying ISS docking adaptor and hatch with toxic hydrazine exhaust gas.

Once the separation between station and vehicle had exceeded 5 metres, Starliner commenced a series of 12 short firings of the forward facing reaction control thrusters on the service module, pushing itself outside the 200-metre Keep Out Sphere (KOS), an imaginary zone around the ISS within which a spacecraft must be on what is called a “4-orbit safe free drift trajectory”, meaning that it can float freely in close proximity with the station for a period of 4 orbits (roughly 6 hours)  without any risk of collision should its manoeuvring system fail.

These burns were more or less a “reversing manoeuvre” in a straight line. Once outside the KOS, Starliner was within the larger Approach Ellipsoid (AE), another imaginary area of space around the station within which spacecraft must be able to float freely for up to 24 hours without risk of impacting the space station. Once in the AE, Starliner continued to move away from the station whilst starting to raise its orbit until some 19 minutes after undocking, it was clear of the AE as well and moving on to an orbit that would carry it around the Earth several times and bring it to the required position for its de-orbit burn.

Once clear of the AE, the ISS involvement in the flight concluded, leaving the NASA Starliner flight team to oversee the rest of the return, an operation of multiple parts.

In particular, the Calypso’s own Reaction Control System (RCS) thrusters were tested. Entirely separate from the problematic thruster systems on the service module, Calypso’s RCS allow the capsule to manoeuvre and maintain orientation once it has separated from the service module after the de-orbit burn, in order for it to successfully re-enter the denser atmosphere.  These 12 thrusters are divided to two “strings” of 6, with only one “string” being used in flight operations, the other being there for redundancy purposes. One of the thrusters did fail to fire during the tests, but posed no threat to the flight.

Similar redundancy exists within the service module RCS (hence why it has 28 thrusters in 4 banks of 7 apiece), and a test of 10 of the unused RCS thrusters on the service module during the same period saw them all operate without a hitch.

Then, immediately prior to the de-orbit burn was due to commence, a final weather check was carried out over the landing zone to confirm everything was above the required minimums for a Starliner landing. These checks include ensuring that winds be no greater than 12 knots, temperatures at ground level will be no lower the -9.4ºC, and the cloud base must not be lower that approx. 300 metres and allow for an all-round visibility of no less than 1.85 km (1 nautical mile). It must also be confirmed that there are no thunder or electrical storms within a 35.4 km radius centred on the landing zone which might interfere with data transmissions / reception. Should any of these criteria not be met, the de-orbit burn would be postponed until such time as all could be met.

As it was, everything was well within tolerances at the landing zone, and at approximate 03:15 UTC, four OMACS – orbital manoeuvring and Attitude Control System– motors on the service module fired in a 59-second burn, with several RCS thrusters also firing to maintain the vehicles overall orientation and attitude, slowing the vehicle sufficiently for natural drag to start pulling it into the denser atmosphere.

Immediately following the de-orbit burn, Calypso separated from the service module and oriented itself so the primary heat shield was at the correct entry for atmospheric interface, whilst the service module dropped into an uncontrolled re-entry so it would burn-up in the atmosphere and any surviving debris full into the southern Pacific Ocean. Calypso reached its re-entry interface – the period when it passed into the upper reaches of the denser atmosphere and experienced maximum re-entry temperatures – some 15 minutes after jettisoning  the service module, and as it approach California’s Baja Peninsula. After this, things happened rapidly.

At 22km altitude, the forward heat shield at the top of the capsule was jettisoned, clearing the way for parachute deployment. This commenced almost immediately with the deployment of the vehicle’s two drogue parachutes, designed to help reduce its speed. These opened slowly over a 28-second period in order to reduce the stress on their canopies and the degree of sudden deceleration on the vehicle.

The drogues were in turn released at 10km altitude, allowing the three main parachutes to deploy and open over a 16-second period, again to reduce the strain on them and the vehicle. They then carried Calypso down towards landing. With a couple of hundred metres left in the descent, the primary heat shield was released, exposing the six airbags sitting between it and the base of the capsule, allowing them to rapidly inflate to cushion the actual landing.

Touchdown came at 04:01 UTC on September 7th, and the recovery teams started their operations shortly after, moving in to the landing site from upwind of the vehicle to avoid risk of any harmful gases from the propulsion systems, etc. Safing of the vehicle and preparing it for transit away from the landing zone proceeded over the course of the next several hours.

With Calypso now on Earth, the focus will shift to trying to rectify the causes of the issues with the service module propulsion systems. As I’ve previously noted, this is made harder as engineers have no physical parts to eyeball; they will have to continue to work on data gathered through ground testing of identical units and data gathered during all the test-firings performed during the flight (including those carried out during the vehicle’s return to Earth).

Calypso, meanwhile, with two flights under her belt, will now return to Boeing for a thorough check-out, overhaul and refurbishment. Although when she or the unnamed Capsule S2 (which performed the seconded uncrewed flight test to the ISS in 2022) will fly again is unclear. Currently, S2 is scheduled to fly the first Starliner operational mission (Starliner-1) in August 2025; however, NASA is now hedging its bets: it has recently double-booked the SpaceX Crew Dragon Crew-11 mission (crew yet to be assigned) to fly in the same period if it becomes apparent Starliner-1 will not be ready to fly.

As previously noted, this means that astronauts Barry “Butch” Wilmore and Sunita “Suni” Williams will be remaining aboard the ISS until February / March 2025, when they will return to Earth on the SpaceX Crew Dragon Freedom. This is due to lift-off from Kennedy Space Centre on or around September 24th, carrying astronaut Nicklaus “Nick” Hague, and cosmonaut Aleksandr Gorbunov to the ISS, where they will complete a 5-day hand-over with the Crew 8 team. The latter are set to depart the ISS around October 1st.

However, Crew 9 will not be the first the reach the station following Starliner’s departure. Soyuz TM-26 is to due to depart the Baikonur Cosmodrome on September 11th, carrying cosmonauts Aleksey Ovchinin and Ivan Vagner, and NASA astronaut Don Pettit.

They will dock with the ISS a few hours later, after a “fast” ascent and rendezvous, and raise the total crew on the ISS to 12. Then on September 24th (the day NASA is targeting for the launch of Crew 9 / Expedition 72), Soyuz TM-25 is set to depart the station and bring Oleg Kononenko, Nikolai Chub, and NASA astronaut Tracy Caldwell-Dyson back to Earth .

Blue Origin Advances New Glenn Maiden Flight, But Without NASA’s EscaPADE

Blue Origin is progressing toward the maiden flight of its New Glenn semi-reusable medium-to-heavy lift launch vehicle – although there are doubts about whether the company will meet the mid-October launch window NASA originally set it.

On September 3rd, the company deployed the new rocket’s 23m tall second stage to its launch facilities at Cape Canaveral Space force Station, Florida, where it will undergo a static fire test of its two Blue Origin BE-3U motors. However, this is just one of a number of milestones the company must meet in very short order if it is to make the mid-October launch window they state they still intend to meet.

This date was set by NASA when Blue Origin offered the flight as the launch vehicle for NASA’s EscaPADE Mars orbiter mission. A part of NASA’s  Small Innovative Missions for Planetary Exploration (SIMPLEx) programme, whereby missions costs are to be reduced by launching them as secondary payloads alongside primary missions, thus reducing their launch costs.

In this, EscaPADE – standing for Escape and Plasma Acceleration and Dynamics Explorers – a pair of identical satellites designed to study Mars’ atmosphere, were supposed to be launched with NASA’s Psyche mission, which originally was going to make a fly-by of Mars whilst heading for asteroid 16 Psyche, eliminating virtually all launch costs. However, Pysche’s launch was revised to a point where the Mars fly-by was no longer possible, and EscaPADE needed a new ride.

The New Glenn second stage raised to its vertical position on on the static fire test stand, Cape Canaveral Space Force Station, Florida. Credit: Blue OriginWhile Blue Origin offered the maiden flight of New Glenn at the bargain basement price of $20 million, it was still more that the original budget for the mission. With the launch facing a host of deadlines, including the second stage static fire test, and things like the integration and testing of the vehicle’s seven first stage BE-4 engines; stacking and integration of the vehicle’s two stages together with the payload and payload fairing; pad roll-out and countdown demonstration tests, NASA has been understandably concerned about Blue Origin’s ability to make the launch window for the last couple of months.

These concerns gained momentum because in order for EscaPADE to be ready for the launch, both satellites must be loaded within toxic hypergolic propellants. This is a costly, time-consuming exercise, and if New Glenn cannot make the October launch window, then NASA will have to go through an equally costly and delicate “de-tanking” exercise and purging of the propellant tanks of the satellites – and then go through the process again when the mission is ready for launch. So the decision was taken to avoid the additional costs and pull EscaPADE from the New Glenn launch. Instead, the agency is looking to launch the mission in spring 2025 – but still using a New Glenn vehicle.

This  in itself has raised eyebrows; optimal launch windows to Mars occur around every 26 months, which spring 2025 does not meet. As such, it currently looks as if EscaPADE, a 990 kg all-up weight – will be the sole payload for the launcher, which will have to throw it into a heliocentric orbit around the Sun and out to Mars on an extended transfer flight.

In the meantime, and as noted, Blue Origin have stated they are still aiming to launch New Glenn on its maiden flight in October. With the removal of EscaPADE, they now intend to use the launch to place its Blue Ring “space tug” into orbit. This is a vehicle at the centre of a new operation for Blue Origin – providing on-orbit maintenance and movement of satellites. The company is also talking to the US government about using the flight to certify New Glenn as  National Security Space Launch system.

As a semi-reusable vehicle, the first stage of New Glenn is designed to be able to land after each use. To achieve this, it will use a sea-going landing barge akin to, but larger than, the SpaceX autonomous drone ship landing platforms. Officially called a landing platform vessel (LPV), the first of these barges arrived at Port Canaveral at the start of September 2024 in readiness for the maiden flight of New Glenn.

Built in Romania and outfitted and commissioned in France, LPV-1 Jacklyn, named for the mother of Blue Origin founder Jeff Bezos (who has also personally financed the company), the 115-metre long platform has already caused raised eyebrows as it has four large structures fore and aft of the 45m wide landing area. It’s not clear if these are integral to the barge (although the do seem to be) and what they might be for.

Certainly, putting such large structures on the barge is an interesting choice. Trying to successfully land a tall, thin tube containing the remnants of liquids that like to go kaboom when mixed and given the excuse, is not exactly a sinecure (just ask SpaceX). As such, hemming-in the landing zone with tall structures that could cause an even greater conflagration were a booster stage to topple into them whilst going the way of said kaboom seems to be somewhat tempting fate; I guess time will tell on that.