Today NASA confirmed persistent rumors that the Mars 2020 project is in trouble. Buried in the agency’s FY2020 detailed budget justification book, released by OMB and the Government Publishing Office this morning, the agency reveals that two of the instruments and the sample caching system “have resulted in mission cost growth.” A NASA official told a planetary science conference this evening that the overrun is about 15 percent.

The Mars 2020 program started in late 2012 after the Obama Administration proposed a significant cut to NASA’s Mars program in the FY2013 budget request, but the Mars science community and their supporters in Congress pushed back.

When it began, the cost was supposed to be no more than $1.5 billion including launch in FY2015 dollars. The idea was that the spacecraft would use spare parts from the Mars Science Laboratory (MSL)/Curiosity program, but have new science instruments. It is scheduled for launch in July 2020.

MSL/Curiosity suffered its own overrun, costing $2.5 billion instead of $1.6 billion, and launching two years late. The excitement over its successful landing after “seven minutes of terror” and the images and data it is sending back seem to have erased any concerns about that history, but it appears Mars 2020 is following a similar course. The Mars 2020 cost already had grown to $2.44 billion by the time of its confirmation review in 2016 and to $2.46 billion by 2018 according to a 2018 Government Accountability Office (GAO) report. This overrun apparently is on top of that.

According to NASA’s budget book, two of the Mars 2020 instruments — the Planetary Instrument for X-ray Lithochemistry (PIXL) and the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) instruments — plus a Sample Caching System to obtain and store samples for later return to Earth are responsible for the overrun.

Lori Glaze, acting director of NASA’s planetary science division, told an audience at the Lunar and Planetary Science Conference underway near Houston this evening that the overrun is about 15 percent according to reporters who were present. Jeff Foust of Space News tweeted the following:

Glaze: cost growth for Mars 2020 is less than 15% of earlier agreed-to cost. In trying to accommodate that within the program first, and then within the Mars program office to avoid impacting the overall planetary program. #LPSC2019 — Jeff Foust (@jeff_foust) March 18, 2019

Paul Voosen reported in Science that Glaze said the extra money would come from operations of existing and future Mars missions and quoted her as saying she tried to “spread it so no one is feeling all of the pain.”

MSL/Curiosity and Mars 2020 are managed by the Jet Propulsion Laboratory (JPL) in Pasadena, CA.

The revelation comes at the same time NASA is beginning a Mars Sample Return (MSR) mission to bring back the samples that will be collected by Mars 2020. MSR is a long sought goal of the Mars science community and was the top priority of the most recent planetary science Decadal Survey, which recommended a series of three missions in cooperation with the European Space Agency to achieve that goal. Obama’s FY2013 budget request scuttled those plans, but a sample return remains a high priority for scientists. Whether the MSR plans will be affected by the Mars 2020 overrun remains to be seen. According to a table in NASA’s budget documentation, the request includes $109 million for “Mars future missions,” although elsewhere it says that money is specifically for “studies and technology development towards a Mars sample return mission.”

Some Mars exploration advocates point out that replacing the spacecraft orbiting Mars that not only study the planet but provide a communications relay between landers on the surface and Earth is another priority, highlighting the strain that the Mars 2020 overrun will put on the Mars program overall.