On Friday, NASA representatives announced that starting with the Artemis mission on SLS rockets, the Centaur unit manufactured by United Launch Alliance will be used. The Exploration Upper Stage was abandoned due to its lack of readiness.
New unit for lunar rocket
On Friday, March 6, NASA management released a series of documents outlining the next steps in the Artemis lunar program. The main thing in this document is confirmation that starting with the fourth mission, the Centaur rocket element developed by United Launch Alliance (ULA) will be used as the upper stage.
NASA Administrator Jared Isaacman stated that it was being done to standardize and simplify rocket assembly. However, in reality, it is much more complicated. At the very beginning of the Artemis program’s development in the 2010s, in order to speed up its progress, it was decided that the Interim Cryogenic Propulsion Stage (ICPS) block, which ULA was already producing but had plans to phase out, would be used as its upper stage.
And then, starting with the fourth mission, it should be replaced by the Exploration Upper Stage, which is more powerful and modern. Years passed, and mission deadlines were pushed back. All three ICPS had already been handed over to NASA. One of them even sent Artemis 1 on a flight around the Moon in 2022. But there was no news about the new stage, not even at the concept level.
Replacement
An unpleasant situation was developing. It was not possible to release new ICPS because even the production line for their manufacture had been dismantled. However, it was necessary to build new SLS rockets from something. Therefore, back in 2024, it was recognized that a replacement for the Exploration Upper Stage needed to be found.
However, no one has yet announced what it will be replaced with. Although NASA does not have many options to choose from. In addition to Centaur 5, there is also a rocket from Blue Origin, but there are simply no other launch vehicles that are even remotely similar in terms of parameters.
And in fact, the intrigue on Friday wasn’t that big. It is clear that it is better to leave Blue Origin as a backup option and use Centaur 5, which is very similar in design to ICPS and is manufactured by the same company.
The only thing that remains unclear at this point is what will happen to the Exploration Upper Stage. Contracts for its development remain in force. Most likely, NASA will use the rules laid down in this year’s budget. They will argue that it is impossible to complete its development and that the order should be canceled.
According to spaceflightnow.com
