Updated Oct. 24 to correct orbit Artemis 1 will fly around the moon.
DUBAI, U.A.E. — NASA officials said they’re now targeting no earlier than February for the Artemis 1 launch as the completed vehicle enters the final phase of launch preparations.
In a call with reporters Oct. 22, agency officials said they had completed the installation of the Orion spacecraft on top of the Space Launch System’s upper stage, wrapping up the assembly of the vehicle for the Artemis 1 launch. The spacecraft had been moved over the Vehicle Assembly Building (VAB) at the Kennedy Space Center Oct. 19.
“Completing stacking is a really important milestone. It shows that we’re in the home stretch towards the mission,” said Mike Sarafin, Artemis 1 mission manager at NASA Headquarters.
The completed vehicle will undergo tests inside the VAB before being rolled out to Launch Complex 39B late this year, said Tom Whitmeyer, NASA deputy associate administrator for exploration systems development. A wet dress rehearsal, where the SLS core stage is fueled and goes through a practice countdown that stops just short of ignition of its four RS-25 engines, is expected in early January. The vehicle will then go back to the VAB for final preparations before going back to the pad for launch.
“We’re looking at a period of time within February” for the launch, he said. “We’re very excited. We think this is really tremendous progress.”
Sarafin said the launch period for Artemis 1 runs from Feb. 12 to 27. A launch on Feb. 12, the first possible opportunity, would take place at 5:56 p.m. Eastern at the start of a 21-minute window. Additional launch opportunities run from March 12 to 27 and from April 8 to 23.
The launch windows are governed by the performance of the SLS. “It really has to do with the three-body that we’re dealing with” involving the vehicle, Earth and moon, including constraints on a daylight splashdown of Orion. “With the Interim Cryogenic Propulsion Stage, we, at certain points in that lunar cycle, are performance constrained.”
Originally, NASA projected just a one-week launch period per month. However, he said mission planners found a way to double the length of the period by changing parameters of the mission. If the launch takes place in the first half of the period, the mission will last six weeks, versus four weeks for launches in the second half. The difference, he said, is taking an extra lap in Orion’s distant retrograde orbit around the moon, which sets up the desired landing conditions.
The briefing was the first formal confirmation by NASA that Artemis 1 will not launch this year. NASA had been holding on to a launch late this year in public statements, although in recent weeks agency leaders had acknowledged that a slip to early next year was increasingly likely.
While Feb. 12 is the earliest possible launch date for Artemis 1, officials stopped short to committing to that day. Whitmeyer said NASA will wait until after the wet dress rehearsal before setting a formal launch date. “We really want to see the results of that test, see how we’re doing, see if there’s anything we need to do before we get ready to launch,” he said.
Once on the pad, there will be other limitations on the launch. “We are limited by the amount of liquid hydrogen that we have,” said Sarafin, which dictates the amount of time the vehicle can stay fueled on the pad on any given launch attempt as well as the timing between launch attempts.
Mike Bolger, Exploration Ground Systems program manager at KSC, said if the first launch attempt is scrubbed, there would be a 48-hour turnaround before the second attempt. A third launch attempt would come 72 hours after that.
The timing of the Artemis 1 launch will also affect the schedule for Artemis 2, the first flight with astronauts on board. The Orion spacecraft on Artemis 2 will reuse avionics flown on the Orion for Artemis 1. “This puts this iron bar of, I’ll say, 20, 21 months between the missions,” said Jim Free, NASA associate administrator for exploration systems development, in an Oct. 13 talk at the American Astronautical Society’s Wernher von Braun Memorial Symposium in Huntsville, Alabama. That means Artemis 2 could not launch any earlier than 20 to 21 months after Artemis 1, or late 2023 assuming a February 2022 launch.
Agency officials on the call said the schedule for Artemis 2 remains uncertain. Whitmeyer noted an independent schedule assessment of that mission will be released in “a matter of weeks” that will answer questions about its timing.
“We’ve got a whole bunch of stuff that we’ve got to do with that crew capsule to get it ready for flight, so we look at the totality of all the different things,” he said. “I don’t think any one thing is the thing that really drives the schedule.”