NASA Readies Second SLS Hot Fire Test, Says Artemis-I Still Possible This Year

NASA Readies Second SLS Hot Fire Test, Says Artemis-I Still Possible This Year

NASA will try again next week to conduct a full duration Space Launch System (SLS) core stage “Hot Fire” test. The first attempt last month ended early because of how the test parameters were set, not hardware problems. If all goes well this time, the first SLS launch, Artemis-I, could still take place this year, but NASA will take it step by step and is not making any promises.

SLS is NASA’s new Saturn V-class rocket to take astronauts, cargo and scientific spacecraft to the Moon, Mars and elsewhere in the solar system. Years late and billions over budget, the rocket’s Boeing-built core stage equipped with four Aerojet Rocketdyne RS-25 engines left over from the space shuttle program is undergoing a series of eight “Green Run” tests at NASA’s Stennis Space Center in Mississippi.

The Hot Fire test is the last one where the engines are fired just as they will be for an actual launch.  In this case, the core stage is bolted to a gigantic test stand so it does not go anywhere, but it is the very rocket that will launch from Kennedy Space Center (KSC) on the Artemis-I mission, not a test article.

NASA, Boeing, and Aerojet Rocketdyne need to test the core stage, which holds the propellant, and engines while ensuring no damage is done. The first time they set the test parameters so conservatively that computers terminated the test after just 67 seconds instead of the planned 485 seconds (8 minutes, 5 seconds).

The SLS core stage being lifted into the B-2 test stand at Stennis Space Center, MS. Credit: NASA

NASA will conduct a second Hot Fire test on February 25.  During a media briefing this morning, Boeing’s SLS Program Manager John Shannon said the test is scheduled to begin at 4:00 pm Central Time (5:00 pm Eastern), but could take place as much as an hour earlier if preparations go smoothly.

Boeing is the prime contractor for SLS and builds the core stage and upper stage. In addition to Aerojet Rocketdyne’s RS-25 engines, SLS also needs two side-mounted Northrop Grumman Solid Rocket Boosters.

Artist’s illustration of an SLS rocket on the launch pad. The core stage is orange. Credit: NASA

NASA’s SLS Program Manager John Honeycutt said today that to get the data needed, the test must last at least 4 minutes, but could run as long as 8 minutes.

NASA SLS Stages Manager Julie Bassler explained there are 10 Detailed Verification Objectives (DVOs) for the test in order to certify the design is ready for all future launches. Complete data for three of the DVOs was acquired during the first test, partial data for six others, and no data for the 10th.  At the 4-minute mark of this test, they will have all the data for all 10 DVOs.  Continuing the test for the remaining 4 minutes will provide data on three secondary objectives.  It also allows the test to match the duration needed for launch and uses up all the fuel so the core stage will not have to be detanked and thus is safer for the ground crew.

If all goes well, Shannon said it will take 30 days to refurbish the engines and load the core stage onto the barge to take it to KSC where it will be “stacked” with the rest of the SLS components.

Components of the Space Launch System carrying an Orion spacecraft. Credit: NASA

The first SLS launch, Artemis-I is an uncrewed test flight of the Orion spacecraft that will take astronauts back to the Moon. The second launch, Artemis-II, will be a test flight with a crew.

The date for Artemis-I has slipped again and again and the program’s cost has grown. In 2014, NASA committed  to the first launch in November 2018. That slipped to December 2019-June 2020, then to mid-late 2021.  More recently, NASA was saying November 2021.

Asked repeatedly about the launch date today, Tom Whitmeyer, NASA’s Deputy Associate Administrator for Exploration Systems Development, insisted there is a “reasonable chance” the launch could take place this year, but does not want to make any commitment right now. First the Hot Fire test must succeed, then the stage must reach KSC and be integrated with the rest of the vehicle and further tests conducted.  NASA wants to be realistic and will take it step by step, keeping everyone apprised of the progress as the months go by.

Prior to the first Hot Fire test, which originally was planned for last fall but was delayed primarily by pandemic- and hurricane-related facility shutdowns, NASA officials said the core stage would have to ship to KSC by January in order to maintain a November 2021 launch date, however. With the ship-to-KSC date delayed at least to the end of March, a launch in 2021 seems quite unlikely despite Whitmeyer’s optimism.

SLS, Orion, and their associated Exploration Ground Systems (EGS) at KSC are all part of NASA’s Artemis program to return astronauts to the lunar surface as part of a sustained era of lunar exploration and utilization. A recent infographic from NASA’s Office of Inspector General (OIG) shows that NASA  had obligated almost $11 billion of the $16.4 billion requested for SLS through June 2020.

Source: NASA Office of Inspector General.

NASA commits to a cost and schedule for each of its programs against which Congress and the White House Office of Management and Budget (OMB) measure performance — the Agency Baseline Commitment (ABC).  In March 2020, the OIG concluded that SLS had exceeded its ABC by 33 percent by the end of FY2019, “a figure that could reach 43 percent or higher” if the first launch was delayed beyond November 2020.  It now has been delayed by at least another year.

Each launch of SLS is expected to cost $1-2 billion, depending on how the cost is calculated. SLS supporters argue costs will come down as the rocket moves into production especially if the launch rate increases. They see SLS as valuable not only for sending humans to the Moon and Mars, but scientific probes that will be able to reach their destinations faster because of the rocket’s power. For example, congressional SLS supporters directed NASA to use SLS to launch the robotic Europa Clipper spacecraft that will study Jupiter’s moon Europa. SLS could get it there in three years by sending it directly instead of needing to swing by other planets to get gravity assists, which can double the trip time. But OMB pushed back because SLS is so much more expensive. OMB prices each launch at $2 billion and insisted NASA could save $1.5 billion using a commercial rocket.

Congress finally relented in the FY2021 appropriations bill. Instead of a flat requirement that SLS “shall” be used, it now says it shall be used “if the SLS is available and if torsional loading analysis has confirmed Clipper’s appropriateness for SLS.”  Last month, NASA issued a Request for Information from potential commercial launch service suppliers, indicating it does not plan to use SLS.

SLS has many critics because of its cost and schedule overruns and the availability of less costly commercial alternatives. But supporters insist the country needs a rocket with SLS’s lift capacity that is owned by the government both to ensure a healthy industrial base and because companies can always decide to walk away from a product if it is not profitable or for any other reason. The industrial base issue is what drove Congress to require NASA to build SLS in the first place. The Obama Administration had just cancelled the George W. Bush Administration’s Ares V rocket because it wanted to invest in new propulsion technologies and design a new, advanced rocket thereafter. Congressional interest, conversely, was giving the space shuttle workforce a place to transfer their talents and keep the United States as the world leader in rocketry, so demanded that NASA build a Saturn V-class “Space Launch System” in the FY2010 NASA Authorization Act.

SLS is managed at Marshall Space Flight Center in Huntsville, AL and the Alabama congressional delegation has been indispensable in keeping it going year after year. Its most ardent advocate, Sen. Richard Shelby (R-AL), recently announced he will not run for reelection next year. For the past several years, he has been the powerful chairman of the Senate Appropriations Committee. With the Senate now under Democratic control, he is now its almost equally powerful Vice Chairman.

Although SLS will still have allies in Congress, Shelby’s departure could create openings for critics to gain ground so it would serve the program well to get at least one successful launch off the pad before he departs at the end of next year.

With the billions of taxpayer dollars already invested and the first launch getting closer and closer, it seems unlikely SLS will be cancelled unless there is major catastrophe, like a launch failure.

That makes it all the more important to have a success when that day finally comes, which means proceeding prudently with the Hot Fire test, but not so cautiously as to delay the schedule much longer.

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