It’s official – NASA will subject SLS rocket to yet another hot shot test

After completing a review of data collected during a hot fire test of its Space Launch System rocket in mid-December, NASA decided it needed to test the large vehicle again. The total engine firing should take place as early as the fourth week of February.

During the test firing on December 16, when NASA intended to run the rocket’s four main engines for up to eight minutes, the test was halted after just 67.2 seconds. NASA said the engine firing was stopped due to a tight limit on hydraulic pressure in the thrust vector control mechanism used to card or steer the engines.

In the days following the test fires in mid-December, NASA and Boeing officials wondered if they would need to test the rocket a second time. While it is helpful to get additional data, they said, there were concerns about the placement of the main stage, with its four main space shuttle engines and large oxygen tanks. liquid and hydrogen, under the stress of repeated testing. (The SLS rocket is consumable, so it is intended to be launched only once.)

According to the agency, the original hot fire test achieved 15 of its 23 goals. Four other lenses got most of the data they wanted, while three had partial data and one had no data. The latter was a test of the reaction of the pressure of the liquid oxygen tank when the liquid oxygen was largely depleted and the tank was emptying. With test targets not met, agency engineers pushed NASA and Boeing executives to perform a second test to reduce the risk of launch failure.

On Friday, NASA made it official. “After evaluating the data from the first hot fire and the previous seven Green Run tests, NASA and the main stage contractor, Boeing, determined that a second, longer hot fire test should be performed. and would present minimal risk to the main stage Artemis I while providing data to help certify the main stage of the flight, ”the space agency said in a blog post.

NASA said running the engines for four minutes during this second test should provide enough data to give confidence in the performance of the main stage, but that the main engines will run for eight minutes if all goes well. .

After the second hot shot test – assuming NASA and Boeing get the necessary data – it will take about a month to refurbish the center stage and its engines. The vehicle will then be loaded onto a barge, shipped across the Gulf of Mexico and into the Atlantic, and delivered to the Kennedy Space Center in Florida. This is now unlikely to happen before the end of March or April.

In its blog post, NASA says that once in Florida, the SLS midstage will be assembled with its solid rocket thrusters and mated with the Orion spacecraft for its first launch “later this year.” However, given that a 2021 launch date was based on shipping the main stage from the Stennis Space Center in January, a 2021 launch of the SLS rocket now seems highly unlikely.