NASA Sets January 17 for SLS Hot Fire Test – UPDATED

NASA Sets January 17 for SLS Hot Fire Test – UPDATED

NASA today set January 17 as the date for the long-awaited hot fire test of the core stage of the Space Launch System (SLS).  It is the last of eight tests in the Green Run series in preparation for the first SLS launch, scheduled for November 2021, that will send an uncrewed Orion spacecraft around the Moon as a step towards returning astronauts to the lunar surface. [UPDATE: NASA HAS MOVED THIS TEST UP ONE DAY, TO JANUARY 16.]

Boeing is the prime contractor for SLS.  This initial version of SLS, Block 1, is composed of the core stage, powered by four Aerojet Rocketdyne RS-25 engines left over from the space shuttle program; two five-segment Solid Rocket Boosters built by Northrop Grumman also derived from the shuttle program; and a Boeing-built Interim Cryogenic Propulsion Stage (ICPS) based on the United Launch Alliance’s Delta IV upper stage.

SLS’s main task is to launch crews aboard Orion spacecraft, built by Lockheed Martin, to the Moon and beyond as part of NASA’s Artemis program. The November 2021 uncrewed launch is Artemis-I. The first launch 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 the lunar surface for the first time since Apollo 17 in 1972.  Many are skeptical of the 2024 date for technical and budgetary reasons.

Illustration of the Space Launch System (the core stage is orange). Credit: NASA

Construction of the first core stage was completed in December 2019 at the Michoud Assembly Facility near New Orleans, LA. It was shipped by barge to NASA’s nearby Stennis Space Center in Mississippi where it has been undergoing tests since then.

SLS has been delayed for years by technical problems and there were more in 2020, but COVID-19 and hurricanes also took a toll on the schedule over the past year.

The hot fire test derives its name from the fact that all four RS-25 engines will be integrated into the SLS core stage and fired together for the first time while firmly attached to an enormous test stand at Stennis.  According to Aerojet Rocketdyne, the engines will fire for 493 seconds (8 minutes 13 seconds), the amount of time they will have to fire to reach orbit when the rocket actually lifts off.  The RS-25s were originally designed to be reusable (although they will not be reused in the SLS program) and these specific four engines flew on several space shuttle missions.

Source: Aerojet Rocketdyne website

The space shuttle used three RS-25s.  SLS needs four and this will be the first time four have been fired simultaneously.

The seven prior Green Run tests have been leading up to this moment. Unexpected problems developed during the “wet dress rehearsal” (WDR) test, the seventh in the series, where liquid oxygen (LOX) and liquid hydrogen were loaded into the fuel tanks. NASA had to pause the first WDR test when the propellant did not chill to the correct temperature. A second test on December 20 automatically stopped minutes early “due to timing on a valve closure” NASA said today.

Nevertheless, NASA and Boeing have decided to proceed with the hot fire test.  Aerojet Rocketdyne CEO and President Eileen Drake said “Our RS-25 team has been working hand-in-hand with NASA and core stage manufacturer Boeing to ensure SLS is ready for liftoff.”

NASA video of the December 20, 2020 SLS wet dress rehearsal at Stennis Space Center where the cylindrical, orange core stage was filled and drained of propellant (733,000 gallons of  liquid hydrogen and liquid oxygen).  The mist is the propellant boiling off during the test.  Credit: NASA

The first flight of SLS has been delayed again and again. In 2014, NASA committed  to the first 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.  Even if the January 17 test is a complete success, it clearly will not meet that date.

The Government Accountability Office (GAO) and NASA’s Office of Inspector General (OIG) have published many reports documenting the cost growth and schedule delays for SLS, but that has not dampened congressional support for the program, managed at NASA’s Marshall Space Flight Center in Huntsville, AL.

In August 2020, Kathy Lueders, head of NASA’s human spaceflight program, revealed NASA’s latest cost figures for SLS itself plus its associated Exploration Ground Systems (EGS) at KSC. If the launch is in November 2021, the development cost estimates for SLS and EGS are $9.1 billion and $2.4 billion respectively, approximately 30 percent increases each. Those represent only development costs. Earlier formulation costs and anything needed after the first launch are not included.

User Comments has the right (but not the obligation) to monitor the comments and to remove any materials it deems inappropriate.  We do not post comments that include links to other websites since we have no control over that content nor can we verify the security of such links.