Like a student late to submit an assignment, NASA has requested an extension from the Space Force that would allow the space agency to perform a third launch attempt of its mega Moon rocket later this month.
NASA’s Space Launch System rocket is currently undergoing repairs following a hydrogen leak that resulted in a second failed launch attempt this past Saturday. The agency is eager to proceed with a third launch attempt in late September and has filed a special waiver request with the Eastern Range to make that happen, as Jim Free, associate administrator of NASA’s exploration systems development mission directorate, told reporters Thursday morning.
No waiver, no launch
The Eastern Range, a branch of the U.S. Space Force, oversees rocket launches from Kennedy Space Centre and Cape Canaveral Space Force Station. The Range issues launch permits but with time restrictions to ensure the public’s safety. Time has expired for NASA’s SLS, which currently stands on Launch Pad 39B at Kennedy Space Centre, which means NASA is required to roll SLS back to the Vehicle Assembly Building and re-test the rocket’s flight termination batteries. The system is designed to destroy the rocket mid-flight, should SLS go astray during launch and threaten populated areas. Trouble is, batteries in the flight termination system need to be tested and recharged at regular intervals.
For the launch period that ended on Tuesday, September 6, the Eastern Range had already issued a waiver that extended NASA’s launch permission from 20 to 25 days. As Free explained, NASA is now requesting yet another waiver and is asking the Range “for a couple of dates” in support of the Artemis 1 mission, in which SLS will launch an uncrewed Orion spacecraft on a journey to the Moon and back. NASA’s relationship with the Range remains “fantastic,” Free said, and that “our job is to…comply with their requirements.” It’s not clear if the Range will abide or when it might issue a waiver, but NASA will need to make a decision on how to proceed should the space agency not hear back in a timely manner, Free said. NASA wants “to be very respectful” of the Eastern Range’s decision-making on the matter, he added.
Should NASA fail to get a waiver, SLS would have to be rolled back to the VAB, allowing technicians to inspect the batteries. This scenario would likely push the third launch attempt to late October, delaying the start of the Artemis era even further. Artemis 1, in which an uncrewed Orion capsule will journey around the Moon and back, is a prelude to Artemis 2 in late 2024, a similar mission complete with a human crew, and eventually Artemis 3, in which NASA seeks to return astronauts to the lunar surface. The Artemis program as a whole is an effort to sustainably return humans to the lunar environment and set the stage for a crewed mission to Mars.
The requested dates are September 23 and September 27 — dates specially chosen as to not conflict with NASA’s upcoming DART mission, in which a probe will deliberately smash into an non-threatening asteroid for the purpose of testing a planetary defence strategy. The DART team will require access to NASA’s Deep Space Network during the test, creating a conflict with the Artemis 1 launch. DART will smash into Dimorphos, the asteroid moonlet of Didymos, on September 26, hence the two non-conflicting dates proposed by the Artemis 1 team. Free said that NASA is looking at a third date in October, but the upcoming launch of the Crew-5 mission to the ISS poses another potential conflict.
Repairs at the pad
In addition to needing the special waiver from the Eastern Range, NASA needs to properly fix and test its stubborn rocket, which failed to launch on the first two attempts. The first failed launch on August 29 was the result of a glitchy sensor, while the second failed attempt on September 3 was caused by an unmanageable hydrogen leak. Ground teams are currently in the process of replacing a seal on the quick disconnect, which connects the liquid hydrogen fuel line on the mobile launcher to the 98.15 m-tall (98-metre) rocket.
At today’s briefing, Mike Bolger, exploration ground systems program manager, said engineers are still not certain if the inadvertent over-pressurization during Saturday’s attempt damaged the seal, but he said the extra pressure did not exceed the quick connect design specifications. Pressure in the hydrogen fuel line is normally controlled by an automated system, but technicians opted for manual operations on Saturday. Bolger said the team didn’t have enough time to practice the procedure, so “we didn’t, as a leadership team, put our operators in the best place we could have.”
A tanking test that’s supposedly not a launch rehearsal
Ground teams are expected to complete their repairs shortly, setting the stage for a major tanking test on September 17, Bolger said. For this test, ground teams would perform a full tanking of the core stage and the upper stage under the usual cryogenic conditions. Bolger said that technicians are planning on a “kinder, gentler” approach to filling the rocket with ultra-cold liquid hydrogen and liquid oxygen. This “kinder, gentler” approach, he later clarified, is based on experience gleaned from green runs and previous rocket launches, and that this “promising” way forward would afford finer control over the tanking process in regards to the slow and fast fill procedures.
The proposed tanking test on September 17 sounds suspiciously like a wet dress rehearsal, but Bolger said it’s most certainly not, as the test won’t involve a countdown rehearsal. A full wet dress is not necessary, he added, saying “we just want to get a good seal,” and that previous wet dress rehearsals of SLS “addressed all requirements.” It was a suspicious comment to make, given that NASA previously admitted to not achieving 10% of its test objectives during the most recent wet dress in July.
A successful tanking test would set the stage for the third launch attempt. For the proposed attempt on Friday, September 23, the two-hour launch window would open at 6:47 a.m. ET, with Orion returning to Earth on October 18. A launch attempt on Tuesday, September 27 would involve a 70-minute window that starts at 11:37 a.m. ET, with Orion splashing down in the Pacific on November 5.
Again, it’s important to keep in mind that these launch dates are hypothetical until the Eastern Range issues a new waiver. Should a waiver not be issued, SLS will have to roll back to the VAB for the required battery re-test. Should that happen, NASA would have to consider a third launch period that runs from October 17 to 31.
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