NASA has announced the push-back of Project Artemis missions in the continuing efforts to return to the Moon with human missions, and with the announcement has come renewed calls for the cancellation of the Space Launch System rocket.
During a December 5th, 2024 briefing, NASA management confirmed that Artemis 2 – the mission to fly a crew of four around the Moon and return them to Earth – will now not occur until April 2026, slipping from the target launch month of September 2025. As a result, the first attempt at a crewed landing under the project – Artemis 3 – has been rescheduled for a mid-2027 launch.
The most significant reason for delaying the missions relates to issues with the primary heat shield on the Orion MPCV (multi-purpose crew vehicle). As I’ve reported in these pages, this heat shield suffered greater than expected wear and tear during the unscrewed test of Orion on a flight around the Moon in December 2022 – something first release to the public in detail in May 2024.
More recently, NASA has indicated that it has identified the root cause of the issues, with comments at that time appearing to suggest part of the solution might involve charges in the construction of the heat shield itself, particularly as the October 2024 update on the issues, Lori Glaze, acting deputy associate administrator, NASA Exploration Systems Development Mission Directorate indicated that while NASA were confident about the cause, as the heat shield for this mission “is already built”, the agency was at that time unsure as to how best to protect the crew during the critical re-entry into the Earth’s atmosphere at the end of the mission.
For assorted reasons, the Orion capsule operates differently to the Apollo Command Module capsule. As it returns to Earth at a high velocity than Apollo, the Orion vehicle does not perform a single re-entry into the atmosphere as Apollo did; instead, it performs what is called “skip guidance”. This involved dipping briefly into the upper atmosphere and using it to reduce speed, prior to making a final re-entry.
The overall goal of this approach is to allow the Orion vehicle to experience somewhat lower temperatures (although still in the order of around 2,700oC) during its “proper” re-entry, than would otherwise be the case were it to simply slam into the atmosphere a-la Apollo and use the friction of that re-entry to slow itself.
However, following the investigations into the excessive pitting (called “char loss”) seen with the heat shield used with Orion on Artemis 1, was an unforeseen result of the skip guidance approach.
While the capsule was dipping in and out of the atmosphere as part of that planned skip entry, heat accumulated inside the heat shield outer layer, leading to gases forming and becoming trapped inside the heat shield. This caused internal pressure to build up and led to cracking and uneven shedding of that outer layer.
– NASA Deputy Administrator Pam Melroy, December 5th, 2024
During the briefing, it was confirmed that no significant redesign of the heat shield is required to overcome this problem; rather the re-entry trajectory for all Artemis crewed missions must be altered in order to minimise the char loss seen with Artemis 1 (remembering that while severe, the damage done to the heat shield in that mission did not reach a point of threatening the overall integrity of the Orion capsule).
For Artemis 2, engineers will limit how long Orion spends in the temperature range in which the Artemis 1 heat shield phenomenon occurred by modifying how far Orion can fly between when it enters Earth atmosphere and lands.
– NASA Artemis FAQ, December 5th, 2024
While an adjustment to the mission parameters is not as drastic as having to build an updated version of the heat shield, it does still require significant computer modelling, updates to flight software on Orion and a re-training of the Artemis 2 crew so they are familiar with the new flight envelope, control protocol and dealing with any alarms / emergencies during the revised re-entry phases of the mission. Hence pushing back Artemis 2 until early-to-mid 2026.
While this does have a knock-on effect for Artemis 3, other factors have come into play which have also contributed to the delay in that mission; some of which many observing Artemis and the choices made (myself included) have long anticipated.
Chief among these is the fact that the SpaceX Human Landing System (HLS) vehicle – a modified SpaceX Starship just wasn’t going to be ready for use in 2026; in fact, there is much to suggest the vehicle will not be ready for any planned 2027 launch of Artemis 3, and that a more reasonable expectation for any Artemis 3 launch would be late 2028, earliest.
However, there are some other factors involved in the Artemis 3 delay; given the changing dynamics and plans for Artemis lunar missions, there is a requirement to make improvements to Orion’s on-board environmental systems. These will not take as long as getting the SpaceX Starship system to the point where it can properly carry out the roughly 12-16 launches required just to get the HLS vehicle to the Moon (leave alone actually construction and testing of the lunar landing vehicle ahead of and use by the crew), but they are a issue which need to be factored into the mission delays.
“Scrap SLS”
The December 5th Artemis announcement saw a further renewed expectation of, and calls for, the cancellation of NASA’s Space Launch System (SLS).
The largest calls for this have come from the SpaceX fan community who frequently (and unfairly) compare the cost of SLS to that of the SpaceX Starship, although there have also been repeated concerns raised from within the US government, such as buy the Government Accountability Office (GAO) and NASA’s own Office of Inspector General (OIG) that the overall cost of SLS is entirely unsustainable.
In particular, the latter offices note that SLS launches will cost around US $2.5 billion each. This includes all elements of a vehicle and the facilities required to launch it – the rocket, its boosters, the re-usable Orion crew vehicle + its service module, the cost of all launch support facilities, etc., together with the cost of future enhancement to the system, such as the Exploration Upper Stage (EUS) which will allow SLS to carry even heavier payloads to orbit. The cost per launch also takes into account the on-going expenditure in developing the system (US $26.4 billion, 2011-2023). As such, and while by no means cheap, its high cost is perhaps better understood.
However, cost isn’t actually the issue here. Rather it is capability. Simply put, there is no other launch system available that is either capable of launching a crewed Orion vehicle to the Moon or rated to do so.
To get to the Moon, the 26.52-tonne Orion and its European Service Module require an additional booster to send them on their way to the Moon. Currently, this booster is the 32.74 tonne Interim Cryogenic Propulsion System (ICPS) for the Space Launch System. It is the only human-rated upper stage capable of boosting the Orion+ESM mass to the Moon and it is only designed to be used by SLS.
And therein lies the rub; whilst people have been bandying ideas of “alternatives” to SLS around like sending human-rated payloads to the Moon is akin to playing with Lego – just stick the bits together you need and away you go, this just isn’t the case.
For example, Falcon Heavy might well be able to lob Orion+ESM+ICPS to LEO off its own back when used in fully expendable mode, a) it must be rated for human flight first; b) it will require significant, potentially costly, and certainly time-consuming, modifications to its core stage and (likely) to the ICPS. These latter points remain true even if the launch is split (e.g. one vehicle to launch Orion+ESM and a second to launch ICPS), which would allow the core and booster stages of Falcon Heavy to be recovered.
And while a split launch might also allow the use of Blue Origin’s New Glenn as an alternative to Flacon Heavy, (a) and (b) remain constraining factors. This is also true of another idea: launching Orion + ESM on New Glenn and then use the Centaur stage of ULA’s Vulcan-Centaur as the kick stage to send them on to the Moon after a rendezvous and docking. But again, again, Centaur is not human rated, and Orion+ESM are not designed to be used with Centaur off-the-shelf. Also, Neither system (nor the ICPS for that matter) are designed for the necessary kind of on-orbit rendezvous and docking, thus, these proposals all add complexity to each and every mission.
This is not to say such alternatives cannot be made possible; it isn’t even necessarily (in the face of SLS launch costs) how much they will cost to bring about; it is the time they would require in order to become feasible, particularly in adapting the disparate system (Orion+ESM (and possibly the ICPS) and Falcon Heavy and/ or New Glenn, and / or the Centaur upper stage) to all play nicely together and reach a point where human missions using them can start. I would venture to suggest reaching such a point in the 2-2.5 years between now and the launch of any Artemis 3 mission (the SLS for Artemis 2 having already been fabricated + currently undergoing assembly / stacking at Kennedy Space Centre) probably isn’t that realistic.
And time is the critical issue here; no programme or project is really “too big to fail”; the more the time frame for Artemis and getting humans back onto the surface of the Moon get repeatedly drawn out (+ the more it is seen to be sucking up available budgets), then the greater the risk an administration and / or Congress could pull the plug to cut losses.
Which is not to say NASA and its incoming new Administrator shouldn’t take a good look at alternate strategies over SLS (and potentially even Orion); rather, they should have a very good game-plan and very realistic numbers on how to proceed and make good on their lunar aspirations before they simply yank out the plug on SLS.
Isaacman Nominated as New NASA Administrator
On December 4th, 2024, the incoming Trump administration announced its choice for the post of NASA Administrator: Billionaire Jared Isaacman, the founder of Shift4, a Payment financial technology company he founded whilst just 16 and which he turned into a multi-billion dollar success.
Passionate about flying and (at least) the human exploration of space, Isaacman is a qualified jet fighter pilot (although has not served in the US military), operating one of the largest fleeting of privately-held jet fighters through another of his ventures, Draken International, a company contracted to provide pilot training to the United States armed forces. He also flies as a part of the Black Diamond Jet Team air display team, and as a solo air show pilot flying a MiG-29UB. And if that weren’t enough, he set a world record in 2009 for circumnavigating the world in a light jet (a Cessna Citation), taking just less than 62 hours to complete the flight, operating the aircraft with two others.
In terms of space activities, his is best known for leading the Inspiration4 private mission to space in 2021, and more recently, the first in a series of planned Polaris missions to orbit, Polaris Dawn, which saw him become the first private citizen to complete what is called a SEVA – or stand-up EVA -, partially-exiting the Crew Dragon space vehicle, a feat also completed by SpaceX employee Sarah Gillis in the same mission.
All of this has resulted in many responding to his nomination as positive movet – and again, some circles see it as a sign that SLS will likely be cancelled: Isaacman has been a strong critic of the system, and clearly leans towards more partnerships such as the one directly benefiting SpaceX. Indeed, his closeness to SpaceX and the fact he has consistently refused to reveal his own financial ties to he company has already caused some concern on Capitol Hill.
Isaacman has also used his position as an “independent space entrepreneur” to call into question NASA pursuing similar deals it has made with SpaceX with other commercial entities, such as Blue Origin. In particular, he is highly critical of NASA working with Blue Origin to develop the latter’s alternative – and potentially more practical / cost-effective and certainly more sustainable – Blue Moon family of lunar landing vehicles, openly stated he “doesn’t like” the fact NASA awarded a second contract for reusable human and cargo lunar landing systems.
Given this, some senators are concerned over questions of Isaacman’s overall neutrality when it comes to NASA contracts, and have indicated this is liable to factor into any confirmation hearings involving him.
Inara Pey: Living in a Modemworld 