NASA Still Aiming for 2021 Launch of Artemis-I If Hot Fire Test Goes Well

NASA Still Aiming for 2021 Launch of Artemis-I If Hot Fire Test Goes Well

NASA is still aiming for the first launch of the Space Launch System (SLS) this year if Saturday’s “hot fire” test goes as planned.  The first SLS core stage, fitted with its four RS-25 engines, is on a test stand in Mississippi waiting for that last of eight Green Run tests where all four engines will fire simultaneously for 485 seconds.

SLS is NASA’s new Saturn V-class rocket designed to send people to the Moon and Mars.  Congress directed NASA to build it in the 2010 NASA Authorization Act after the Obama Administration cancelled the Ares V rocket that was part of the George W. Bush Administration’s Constellation program to achieve that goal.

In 2014, NASA committed to the first SLS launch in November 2018. That slipped to December 2019-June 2020, then to mid-late 2021.  Most recently, NASA has been saying November 2021, but that was premised on completing the Green Run tests and shipping the core stage to Kennedy Space Center (KSC) in mid-January 2021.

If Saturday’s test is successful, the plan now is to ship it in February. NASA’s SLS program manger at Marshall Space Flight Center, John Honeycutt, said at a media briefing today that will support a launch in 2021, but was not specific about when.

The first launch of SLS will take an uncrewed Orion spacecraft on a trip around the Moon. The first flight with a crew, Artemis II, is expected in 2023.  Under the Trump Administration’s schedule, Artemis III would launch in 2024 and deliver astronauts to lunar orbit who would then descend to the lunar surface, returning Americans to the lunar surface for the first time since the Apollo 17 mission in 1972.

Many question that schedule, but whatever it turns out to be, the first step is Artemis I.

Boeing is the SLS prime contractor and built the liquid oxygen/liquid hydrogen core stage. Aerojet Rocketdyne builds the RS-25 engines. These specific engines are left over from the space shuttle program and have flown many times, but the shuttle used only three.  The January 16 test is the first time four will be fired together in the SLS configuration.

The SLS core stage with its four Aerojet Rocketdyne RS-25 engines being transported from the Michoud Assembly Facility near New Orleans, LA to a barge for the trip to Stennis Space Center, January 2020. Photo Credit: NASA.

The Green Run is a series of eight tests. This hot fire test, where the engines are ignited for 485 seconds, is the finale.  Aerojet Rocketdyne’s Jeff Zotti said they will generate 1.6 million pounds of thrust as they consume 700,000 pounds of propellant. The duration is the same as what is needed to reach space.

Preparations begin tomorrow for the test, which is scheduled for 5:00 pm EST (4:00 pm Central Time) Saturday.  NASA has not announced when NASA TV coverage will begin.  NASA actually moved this test up one day.  It had been scheduled for January 17.

This time the core stage will be attached to an enormous test stand at Stennis Space Center near Bay St. Louis, Mississippi.  The next time the engines fire, it will be from a launch pad at Kennedy Space Center, Florida.

The SLS core stage being lifted onto the B-2 test stand at Stennis Space Center. Photo credit: NASA

Officials stressed repeatedly today that this is the very core stage that will be used for Artemis I, meaning they have to proceed cautiously. Boeing Vice President and SLS Program Manager John Shannon emphasized this is a “flight article” not a “developmental or test article … so we’re being very careful with it as we go” through the Green Run series.

Honeycutt agreed. “The reason we test is to learn and from my perspective and the team’s perspective we don’t want to do anything to put the vehicle at risk.”

A final go/no-go decision for the test will be made at T-10 minutes.  Shannon said that although the test is scheduled for 485 seconds, they will have all the data they really need after 250 seconds and if anything goes awry and the test ends early it could still be considered a success.

If the test does not go as planned, however, Julie Bassler, SLS Stages Manager at Marshall, said they need 7 days before they can try again.

After the test, Bassler’s team will review the data to make sure they have everything they need and inspect the hardware before making a plan to load the core stage onto a barge for the trip to KSC.

The expectation was that all eight tests would consume about 10.5 months and considering that Stennis was closed for about 3 months in 2020 due to COVID-19 and a series of hurricanes “that’s about where we are right now,” Shannon said.

The core stage is just one component of SLS.  Others include two 5-segment Northrop Grumman Solid Rocket Boosters and a Boeing upper stage called the Interim Cryogenic Propulsion Stage. The Lockheed Martin-built Orion spacecraft goes on top. All those pieces already are at KSC.  It will take many months to “stack” them all together, a process already underway.

NASA illustration of the components of the Space Launch System.

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