Last week, NASA and its myriad of contractors for the Space Launch System and Orion spacecraft reached a significant milestone – the creation of a full stack of the rocket and space capsule for the first time. The finished launcher stands an impressive 98 meters high inside the Vehicle Assembly Building of the Kennedy Space Center.
Although technicians and engineers have yet to subject the rocket and spacecraft to a series of tests in the coming months, the agency was debating a possible launch window for the Artemis I mission for the first time. This launch, which sends an unmanned Orion spacecraft into orbit around the moon and back, could take place in a 15-day window from February 12th to 27th.
In order for NASA to create this start window, a lot and more has to go right. So it is likely that the launch of Artemis I will slide further into the spring of next year. If serious technical problems are discovered, the start date could of course be delayed even further. During a press conference with reporters on Friday, launch officials repeated several times that the missile would not launch until the hardware was ready.
“We need to successfully complete a number of activities,” said Tom Whitmeyer, assistant assistant administrator for exploration systems development at NASA headquarters. “As an agency, we strive to do this step by step. We are absolutely determined to take it step by step.”
Major activities the launcher must perform include ramping up the entire launcher and spacecraft, rolling the stack out to the launch pad, performing a “wet rehearsal”, and returning to the vehicle assembly building to install some pyrotechnics for the actual launch and then back to the launch pad.
All of these will be new activities so there are likely to be some technical issues. The wet dress rehearsal will be the most dynamic test of the launcher in terms of its hardware, the new ground systems in the Kennedy Space Center and the software for the integrated vehicle. During this test, the vehicle is completely refueled with liquid hydrogen and liquid oxygen and a countdown to approximately T-10 seconds is performed. The interfaces between the rocket, spacecraft and ground systems have never been tested in this way, and problems have arisen here with new vehicles in the past.
After successfully completing the wet dress test, which is currently planned for “early January”, NASA will be more confident in setting a start date for the Artemis I mission.
However, Artemis I mission manager Mike Sarafin discussed possible launch windows for the vehicle. In essence, he said, there will be about two weeks that it will be possible to start on a lunar orbit and two weeks off. This is because Orion needs to inject during the day for good data to be collected. After the starting window in February, which opens on February 12, the next two-week window opens on March 12, followed by one on April 8.
The overall objective of this mission will be to test the SLS rocket in flight for the first time and demonstrate Orion’s ability to return to Earth under lunar reentry conditions. Depending on the start date, the mission lasts either four or six weeks.
By completing the stacking of the rocket, NASA has shown that it is on the home stretch of finally launching a rocket that was originally supposed to launch in late 2016 but has experienced costly and lengthy delays.
NASA isn’t there yet, however. The agency needs to be careful with this missile because their next SLS vehicle is expected to be unavailable to fly in about two years, and if that launch fails catastrophically, it would raise questions about the future of the program, which is much cheaper privately developed heavy-lift missiles to begin to fly.
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