The POT the program continues to advance Artemis after the reset announced two weeks ago that plans to accelerate the cadence of flights, among other changes. According to SpaceNews, the space agency already has the replacement of the current second stage of the Space Launch System (SLS) rocket that it will use from Artemis IV. This is the upper stage Vulcan Centaurof United Launch Alliance (ULA).
With similar dimensions and specific impulse ratings, the Centaur It is an almost direct substitute and ensures the continuity of the SLS as a viable launch vehicle for many more years.
In principle, the version Block 1B of the SLS was to start flying with Artemis III and use the future upper stage Exploration Upper Stage (EUS) as a replacement for the current Interim Cryogenic Propulsion Stage (ICPS). However, NASA announced in February that it was stopping development of Block 1B and Block 2although you still need to replace the ICPS from Artemis IV because this stage is only planned for the first three missions and derives from the rocket Delta IValready retired and without production lines. The Centaur fits that role.
The current ICPS has a height of 13.7 meterstotal mass of 32,066kgmaximum thrust 110.3kN and specific impulse 465.5 secondswith a delta v of 4,565 km/s. In comparison, the improvements planned for the Centaur will give it a height of 12.5 metersmass of 53,615kgmaximum thrust 214.6 kN and specific impulse 460.9 secondswith a delta v of 4,520 km/s. Delta v is the total capacity of a ship or rocket stage to change its speed and, thereby, modify its trajectory.
Although there are differences in height, mass and thrust, the final delta v that it will be able to provide to any payload placed above it should be relatively similar. With the Centaur production line already established, which is also used in the rocket Vulcan from ULA, NASA has a reliable second stage for future SLS designs.
NASA rules out Jeff Bezos’ option
NASA also studied using the upper stage of the New Glenn of Blue Origin (the aerospace company of Jeff Bezos, owner of Amazon) as a substitute for the ICPS, but considered that still too experimentalsince it has only flown twice so far. In comparison, Different versions of the Centaur have been flying since the 1960s.
‘ULA’s consolidated infrastructure, its resources, its flight history, the already existing integration between programs and the familiarity with the Centaur upper stage manned certification represent the only currently viable option for the Government to meet the objectives and requirements of the Artemis missionswhile maintaining the agency’s programmatic goals,’ NASA concludes in the document accessed by the media.
Although it is planned that the SLS’s place will be taken by the Starship of SpaceX In the future, as long as delays and technological obstacles are not resolved, It does not seem that the rocket will be ready for the missions that were scheduled at the time. With the United States accelerating its return to the Moon, Getting the SLS into operational condition for post-Artemis II and III missions will give NASA more launch options for future lunar landings.s.