NASA IG Urges Congress to Remove Requirement to Launch Europa Clipper on SLS

NASA IG Urges Congress to Remove Requirement to Launch Europa Clipper on SLS

Paul Martin, NASA’s Inspector General, urged Congress today to remove the requirement in law that NASA launch the Europa Clipper mission on the Space Launch System (SLS).  Congress has included that requirement in NASA’s annual appropriations bills for the past several years. NASA has pushed back for just as long on the basis that a commercial rocket would be much less expensive and SLS is needed for its effort to return humans to the Moon.  NASA must soon decide on a launch vehicle and Congress is working on the final details of the next appropriations bill, so time is of the essence.

Europa Clipper will investigate Jupiter’s moon Europa. Many scientists believe a liquid ocean exists under Europa’s icy crust and microbial life may have developed there.  Former Congressman John Culberson (R-TX), who once chaired the House Appropriations Commerce-Justice-Science (CJS) subcommittee that funds NASA, was an avid advocate for the mission. He added millions of dollars to NASA’s budget year after year to build and launch it, specifying in law not only the launch vehicle, but when it must be launched. Originally the date was 2022, but the FY2019 appropriations bill let that slip to 2023.

Although Culberson lost his reelection bid, and Democrats are now in control of the House, the new CJS subcommittee chairman, José Serrano (D-NY), apparently is also an enthusiast.  He was the subcommittee’s Ranking Member while Culberson was chairman.  The House-passed version of the FY2020 CJS bill continues to require that Europa Clipper be launched in 2023 on SLS.

The law also requires NASA to build a Europa Lander for launch on SLS in 2025 although the agency is not pursuing that at the moment.

NASA did not have any Europa mission in its plans until Culberson directed the agency to add it.  NASA is following the law and building Europa Clipper, but continues to push back on the launch date and launch vehicle.  The agency’s commitment right now is for launch in 2025, although 2023 is characterized as the target launch date.

Artist’s illustration of Europa Clipper flying over Europa with Jupiter in the background. Credit: NASA-JPL-Caltech

Europa Clipper just passed a key milestone, its confirmation review, last week.  That allows the program to proceed to completion of final design, followed by construction and testing of the spacecraft and its instruments.  A NASA spokeswoman told that the mission’s baseline life-cycle cost is $4.25 billion and NASA continues to “dialogue with Congress about the Europa Clipper mission and its launch vehicle needs taking into consideration the availability of the Space Launch System rockets and any potential impact to the Artemis program launch schedule.”

Martin’s letter today feeds into that dialogue.

The first SLS launch is now expected in 2021, an uncrewed test flight as part of NASA’s Artemis program to land astronauts on the Moon by 2024.  The second and third launches, in 2022/2023 and 2024, also are dedicated to Artemis.

In his letter to House and Senate appropriators and authorizers, Martin explained that NASA is following congressional direction to get Europa Clipper ready by 2023, but an SLS rocket likely will not be available until 2025 because Artemis has priority.  That means the spacecraft will have to be placed in storage for two years at a cost of $3-5 million per month according to estimates by the program’s Standing Review Board (SRB). Martin said NASA is allocating $250 million of program funding being held in reserve to cover storage, personnel and other costs associated with a launch delay.

The SRB also estimates that using a commercial rocket, either the United Launch Alliance’s Delta IV Heavy or SpaceX’s Falcon Heavy, instead of SLS would save $700 million.  In total, then, Martin argues that not using SLS could save “up to $1 billion.”  That is the sum of $250 million in reserves plus $700 million in launch cost savings, rounded up.

The advantage of using SLS is that it is very powerful and can send spacecraft like Europa Clipper on a direct trajectory to their destinations, shortening the trip time.  With the less powerful commercial rockets, the spacecraft must get additional speed by swinging by other planets to get a “gravity assist.”  In the case of Europa Clipper, that would more than double the trip time from 2.4 years to 5.9 years.  That would incur costs for personnel to monitor the spacecraft, slightly offsetting the savings from the price of the launch vehicle.

Martin’s bottom line is that Congress should give NASA the flexibility to decide what rocket to use rather than imposing a legal requirement.

NASA’s renewed focus on returning humans to the Moon on an accelerated timetable means that an SLS will not be available to launch the Clipper mission to Europa before 2025 at the earliest.

Given all of the foregoing factors, we urge Congress to consider removing the requirement that NASA launch the Europa Clipper on an SLS and allow the Agency to decide whether to use an SLS or a commercial vehicle based on cost, schedule, vehicle availability, and impact on science requirements. — NASA Inspector General Paul Martin

SLS is managed by Marshall Space Flight Center in Huntsville, AL.  Senator Richard Shelby (R), the senior Senator from Alabama, is chairman of the Senate Appropriations Committee and a strong SLS advocate. Delta IV is also built in Alabama. His committee is currently finalizing its version of the FY2020 appropriations bill for NASA and the Senate is expected to take it up after it returns to work on September 9.  FY2020 begins on October 1.

Martin points out that NASA must begin procurement of the launch vehicle “in the next few months.” If Congress is to relax the SLS requirement, now is the time to do so.

Today’s letter is a follow-up to a May 2019 report from Martin’s Office of Inspector General (OIG) that was highly critical of NASA’s management of the Europa Clipper program.

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