NASA’s Megarocket Gets Closer to First Launch After Successful Engine Tests

NASA’s Megarocket Gets Closer to First Launch After Successful Engine Tests
A view of SLS inside the Vehicle Assembly Building at NASA's Kennedy Space Centre, showing the tops of the side rocket boosters. (Photo: NASA/Cory Huston)

A faulty memory chip caused a problem last year with NASA’s upcoming Space Launch System megarocket — an issue the space agency says is now resolved.

A wet dress rehearsal appears to be closer than ever after a successful series of tests done on all four RS-25 engine flight controllers, according to a NASA release. In December 2021, one of these flight controllers began to misbehave, but the replacement unit, along with the pre-existing engine controllers, now appear to be functioning properly. The problem seemingly resolved, NASA can now focus on the final close-outs as it prepares for the inaugural launch of the 101.19 m-tall (101-metre) rocket, a mission known as Artemis 1.

The SLS rocket inside the Vehicle Assembly Building at NASA's Kennedy Space Centre in Florida. (Photo: NASA/Frank Michaux)The SLS rocket inside the Vehicle Assembly Building at NASA’s Kennedy Space Centre in Florida. (Photo: NASA/Frank Michaux)

“All four engine controllers performed as expected during power up,” according to the NASA statement. Aerojet Rocketdyne, the developer of the RS-25 engine, has been working with the space agency to resolve the problem and assist with the recently concluded tests. The 5.75-million-pound rocket is currently undergoing integrated testing inside the Vehicle Assembly Building at NASA’s Kennedy Space Centre in Florida.

The flight controller on engine number four had to be replaced after it glitched out late last year. These devices communicate with the rocket to provide precision control and to report on the health of each RS-25 engine, which dates back to the Space Shuttle program.

NASA traced the cause of the malfunction to a faulty memory chip. This chip is only needed during the controller start-up sequence, and it has no impact on controller operations aside from that lone function, NASA says. No problems with the three other memory chips were detected, in what is a very positive sign.

The controller problem forced NASA to delay the much-anticipated wet dress rehearsal, in which the rocket will be rolled out to Launch Pad 39B and filled with propellant. That said, NASA recently admitted that the sheer volume of testing has also responsible for the delays. A wet dress rehearsal was originally scheduled for late January, and then for early February, with the latest word that it could happen in March.

Next steps include pre-flight diagnostics and the final hardware closeouts, such as tests with the flight termination system and last-minute installations on the two solid rocket boosters. The wet dress rehearsal, in addition to being a practice run, will provide NASA with important data for evaluating the overall performance of the system. NASA will set a launch date for Artemis 1 following a successful wet dress rehearsal. An April launch is not out of the question, but we’ll hold off on making any firm predictions.

SLS is a huge deal for NASA, as it will enable the upcoming Artemis missions to the Moon and Mars. Once complete, it will be the world’s most powerful rocket — at least until SpaceX launches its fully stacked Starship, which is likewise expected to go up later this year.

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Editor’s Note: Release dates within this article are based in the U.S., but will be updated with local Australian dates as soon as we know more.