ARS Technica by Eric Berger - 5/1/2020
Notably, the space agency seems to have taken an upgraded SLS off the table.On Thursday, NASA announced awards to begin final design and initial development of landers to carry humans down to the Moon—a big step for the Artemis Program.
Building these landers to reach the lunar surface by 2024 is a big challenge, as it leaves a little more than four years to design, build, test, and fly these complex vehicles. After all, it took Grumman more than six years to build the Lunar Module in the 1960s, and the company had done some preparatory work before NASA issued its first contracts.
But assuming at least one of the three lander concepts is ready to go by 2024—Blue Origin's Blue Moon lander, Dynetics' landing system, or SpaceX's Starship—there remains the question of how to get it to the Moon. NASA has not settled upon a final architecture for the Artemis III mission to land on the Moon in 2024, and a choice of four rockets remains.
It is noteworthy that none of these rockets has yet taken flight. In fact, for its human program, NASA has eschewed the most powerful rocket currently in existence, the Falcon Heavy, as well as the Delta IV Heavy booster, which already has launched NASA's deep-space Orion spacecraft to an altitude of 5,800km.
More:
https://arstechnica.com/science/2020/05/nasa-is-counting-on-a-lot-of-unproven-rockets-for-its-artemis-plan/
