This approach gives companies more flexibility and may save NASA money.
In contrast to Apollo, where the giant Saturn 5 rocket carried all of the pieces needed for a moon landing, NASA this time will employ a more complex choreography for the new missions, named Artemis. (In Greek mythology, Artemis is the twin sister of Apollo.)
First, NASA will construct a lunar outpost called Gateway. It will orbit the moon in a highly elliptical path that comes as close as 1,000 miles and swings as far out as 43,500 miles. Then the pieces of the landing system will be sent to the Gateway.
The landing system will consist of three pieces — a transfer module that moves the astronauts and the other pieces of the lander from the Gateway to an orbit much closer to the moon; a descent module that guides the lander to the lunar surface; and an ascent module that lifts the astronauts back into space after their stay on the moon.
While the first Artemis moon landing will carry only two astronauts, the same as the Apollo missions, they should have more spacious accommodations. With the ascent stage stacked on top of the lander, the spacecraft will be somewhat heavier, somewhat wider and considerably taller than the Apollo landers.
That will allow a longer stay of about a week on the moon’s surface. During Apollo 11, the first moon landing in 1969, Neil Armstrong and Buzz Aldrin were on the moon for less than a day. During Apollo 17, the last time humans landed, Harrison Schmitt and Eugene Cernan stayed for just over six days.
When all of the pieces are in the place, the astronauts are to launch in an Orion capsule atop a Space Launch System rocket to the Gateway where they will board the lander for the moon. They are expected to land near the moon’s South Pole and spend about a week there.
But in the compressed timelines — after revising a couple of drafts, NASA issued a final call for proposals on Sept. 30, and companies must send in submissions by Nov. 1 — some companies realized that they might not have all the pieces to put together a strong proposal.