WASHINGTON — NASA has set aside three days in late August and early September for the first launch of its Space Launch System rocket to send the Orion spacecraft into orbit around the moon and back.
During a July 20 briefing, NASA officials announced they had August 29, September 2 and September 5 launch dates for the Artemis 1 mission, an unmanned test flight of the Orion spacecraft and the first launch of the SLS. Orion will spend up to six weeks in cislunar space before crashing off the coast of San Diego.
“We think we’re on track to achieve efforts on those dates,” Jim Free, NASA’s associate administrator for exploration systems development, said during the call.
Crews have been working on SLS and Orion since it returned to the Vehicle Assembly Building (VAB) on July 2 after its fourth wet dress rehearsal, where the rocket was loaded with liquid oxygen and liquid hydrogen propellants and went through a practice countdown. That included work to repair a liquid hydrogen leak on the nuclear trap found during that test.
During that work, engineers discovered a loose fitting, called a collet, where the liquid hydrogen line connects to the rocket. That required going into the motor portion of the rocket to tighten the fitting. “That actually gave us a little pause to wonder if we could make a launch date on those three dates,” Free said. Now that those repairs were complete, he said he was more confident he was ready for those dates.
Free and other NASA officials warned during the call that they still had work to do on both SLS and Orion to get the vehicles ready for launch. If those preparations stay on track, the vehicle would roll back to Launch Complex 39B about Aug. 18, although a final decision on whether to proceed with a launch attempt would come after a flight readiness assessment about a week before launch.
The three launch dates have different launch windows and mission durations:
The August 29 launch window opens at 8:33 a.m. Eastern for two hours, and would result in a 42-day mission ending with a landing on October 10. The September 2 launch window opens at 12:48 a.m. Eastern for two hours, and would result in a 39-day mission that crashed on Oct. 11. The September 5 launch window opens at 5:12 p.m. Eastern for 90 minutes, and would result in a 42-day mission crashing on October 17.
All three are considered “long-class” missions by NASA, with launch capabilities on other days instead supporting shorter missions of about four weeks. “We don’t have a strong preference for whether it’s a short-class or long-class mission,” said Mike Sarafin, NASA Artemis mission manager. Both support all the mission objectives of launch vehicle and spacecraft testing, with a particular emphasis on demonstrating Orion’s heat shield on a return at lunar return speeds.
A complication in launch planning is the missile’s flight termination system (FTS) batteries. That includes performing a launch no more than 20 days after a final test of the system. “With our three attempts, we have issues with that timing,” said Cliff Lanham, Senior Vehicle Operations Manager at NASA’s Exploration Ground Systems program. NASA is working with the Eastern Range to see if there are ways to address that problem.
Another problem is that the FTS batteries are located on parts of the SLS that are not accessible from the pad. That means, if the vehicles roll onto the pad in August but don’t launch on September 5, it will have to send the VAB back for additional testing and reset the clock.
That would make it difficult to get the vehicle ready for the next launch window, which runs from September 20 to October 4. “That would be a real challenge for us, to be honest,” Lanham said of the launch during that period. time frame. “But we would certainly do our best.” The next launch period will run from October 17 to 31.