Space Sunday: Starship, ExoMars and sundry news

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

ESA Confirms Rosalind Franklin Will Not Launch until at least 2024

It is been a long and frustrating road for Europe’s first Mars rover. The project started 20 years ago, with the idea the rover could be operating on the surface of Mars by 2010 – an exceptionally ambitious goal even under the best of circumstances; and the rover – then simply called ExoMars was to have anything but the best of circumstances.

For a start, the contract to design the rover wasn’t awarded until 2007, so there was no way it would be ready for launch in 2009. Then in 2009, the decision was taken to combine the rover mission with that of the Trace Gas Orbiter (TGO), placing them both under the “ExoMars” banner, and launch them on a Russian Proton-M launcher. This required a complete downsizing the rover so it could piggyback on the orbiter.

Things then got more confused when NASA muscled in on the project, offering to provide an Atlas V launch vehicle for ExoMars, so long as room was made for their own mini-rover, MAX-C. Whilst this meant TGO and the European rover would get a free ride to Mars (NASA would cover the Atlas V launch costs) It also meant the rover had to be further redesigned. Then, by 2011, it was clear NASA was having second thought about the collaboration, prompting ESA to start looking for alternatives, and in 2013, NASA did unilaterally withdraw from the partnership.

Fortunately, ESA had by that time re-engaged with Russia, and reached an agreement by which TGO – which by 2013/4 was at an advanced stage of development – would launch on a Proton-M in 2016, and the rover would launch separately on a second Proton-M in 2018, with Russia providing a lander vehicle (called Kazachok) and which would also carry its own 45 Kg suite of science instruments, to the surface of Mars. The benefit of this approach mean that the rover could revert to its original, large design and a full 26 Kg suite of science instruments.

ESA’s ExoMars rover Rosalind Franklin will now no launch to Mars before 2024 at the earliest. Credit: ESA

Included with the 2016 TGO mission was a small lander called Schiaparelli, designed to test systems that would be used in the rover’s Entry, Descent and Landing (EDL) system. Unfortunately, Schiaparelli suffered a malfunction during its EDL, crashing into Mars at considerable speed. This prompted ESA to push back the rover’s launch from 2018 to 2020, giving more time for EDL development and for the science packages on both the rover and the lander to be completed.

By 2018 the rover has been named Rosalind Franklin in honour of the forgotten heroine of DNA/RNA research, but the problems refused to go away. First there were issues with the large supersonic parachute designed to slow the rover and its lander through the Martian atmosphere, which would require time to correct, then the COVID-19 pandemic hit and delays built up due to restricted working practices, forcing ESA and Roscosmos to push the launch back to July 2022.

In the wake of the Russian invasion of Ukraine, cooperation between ESA and Roscosmos all but stopped – although it had appeared that given its flight readiness, ExoMars might slip through. However, at a recent meeting of ESA member states, a vote was taken to suspend all work on the mission and delay the launch until the next available launch window that opens in late 2024.

But whether or not the rover actually does get to fly in 2024, is still a matter of debate; Roscosmos has indicated there can be “no coming back” from any breaks in cooperation between itself and ESA / Europe, and to this end has already repurposed several launches originally intended for ESA / European missions for domestic purposes, forcing ESA to seek launch opportunities elsewhere. Were the ExoMars rover to suffer a similar situation, it would undoubtedly be delayed beyond a 2024 launch opportunity.

NASA Human Landing Systems Update

NASA has formally announced the competition to obtain a second Human Landing System (HLS) for missions to the surface of the Moon. Called Sustaining Lunar Development, the competition had been expected ever since Congress directed the agency to fulfil its original promise to oversee the development of two HLS systems.

Under the terms of the competition, SpaceX is barred for submitting any proposal, but the way is open for for the two other contenders for the original HLS contract – the National Team, lead by Blue Origin, and Dynetics – to participate. The aim of the competition is to provide NASA with a highly flexible, sustainable system to deliver cargo to the surface of the Moon and to ferry crews between the lunar surface and the Lunar Gateway station, once this is available for use.

NASA has formally announced the competition to select a further Human Landing System (HLS), with two potential contenders being Dynetics (l) and the National Team lead by Blue Origin (r). Image credits: Dynetics, SpaceX and Blue Origin.

As it is unlikely any additional HLS vehicles will be ready in time for the second crewed lunar landing – set to take place in 2027/28 with Artemis 5 (Artemis 4 being focused solely on the Lunar Gateway station), NASA has also officially actioned “Option B” of its contract with SpaceX and their Starship-based HLS.

This means that – as has been recently rumoured – rather than just providing their HLS for the initial lunar landing attempt of Artemis 3 (“Option A” of the contract), SpaceX ensure their vehicle is capable of making and second descent to, and return from, the surface of the Moon in support of the Artemis 5 mission.

SLS Testing Delays Axiom Private Flight to ISS

Following the roll-out of its first Space Launch System (SLS) rocket to Kennedy Space Centre’s Pad 39B (see: Space Sunday: a big rocket, a telescope & yellow and blue), NASA has indicated that the vehicle’s long-awaited wet dress rehearsal (WDR) will likely take place on Sunday, April 3rd, 2022.

As I reported in my previous Space Sunday update, this will see the vehicle – due to launch the first Artemis mission towards cislunar space later this year – undergo a full launch dress rehearsal, including filling the core stage propellent tanks, terminating at the point at which the four main engines would otherwise ignite. It’s a final critical step in the vehicle’s journey towards flight readiness, and if all goes according to plan with the WDR and the tests that follow in the days after, the vehicle will be returned to the Vehicle Assembly Building to undergo final checks in preparation for a launch that could come as soon as May 2022.

The Sun lowers behind the Artemis 1 SLS vehicle as it sits on its mobile launch platform at Kennedy Space Centre’s Pad 39B. Credit: NASA

However, April 3rd is also earmarked for the launch of the Axiom / SpaceX AX-1 mission flying a crew of four – former NASA astronaut, Michael López-Alegría and three customers: Larry Connor, Mark Pathy and Eytan Stibbe – to the International Space Station in the first of a series of missions that will culminate in adding a commercial module to the station.

This mission, using a SpaceX Crow Dragon / Falcon 9 booster, is set to lift-off from the neighbouring Pad 39A, which shares the supply of of various consumables from the same reserves as Pad 39B. So if NASA call priority on the SLS WDR, then AX-1 will likely be delayed by at least 24-48 hours so that the consumables reserves can be fully restocked. This shouldn’t impact the goals of the 10-day mission, which has launch windows pretty much every day through April; but if there is a further cause of delay – weather, technical, or whatever – that pushes the launch beyond April 7th, it could delay the launch of the NASA Crew-4 mission by several days.

If so, this will continue to leave the ISS somewhat crowded for a short period, with 11 people occupying it – one up from the current crew of 10, three of the current personnel on the stations – US astronaut Mark Vande Hei and cosmonauts Pyotr Dubrov  and Anton Shkaplerov – being set to depart the station aboard Soyuz MS-19 on Mach 28th (and despite seemingly empty threats by Roscomos chief Dmitry Rogozin to leave Vande Hei on the station in retaliation against Ukraine-related sanctions imposed on Russia by the United States).

Major Hubble Discovery to be Announced

NASA and the Space Telescope Science Institute have indicated they will announce a major discovery by the Hubble Space Telescope on Wednesday, March 30th.

No details are available on what the announcement might contain, but NASA is referring to it as an “exciting new discovery” which “not only extends our understanding of the universe, but creates an exciting area of research for Hubble’s future work with NASA’s newly-launched James Webb Space Telescope”.

So hopefully, more on this in my next Space Sunday report!

2 thoughts on “Space Sunday: Starship, ExoMars and sundry news

  1. In the 4th graph, you wrote, “a scary e-mail from Musk at the end of 2022.” Did you mean the end of 2021?

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