After years of being pushed by the U.S. Congress to follow the Europa Clipper, a spacecraft that will survey Jupiter’s frozen moon, with a lander, NASA has begun to push back. The agency disclosed today that the lander mission, if it happens, will now come no earlier than 2030, 5 years later than Congress mandated. And the agency will be challenged to meet the 2023 launch date set for the Clipper.
Thanks to the watery ocean beneath its icy crust, Europa has loomed for several decades as a prime target in the search for life outside Earth. But unlike the $3 billion Europa Clipper, a flagship NASA mission under development that will conduct periodic flybys of the moon, the Europa lander has not been rated as a high-priority mission by planetary scientists. Instead, support for the lander was largely marshaled by former Representative John Culberson (R–TX), who, until his election defeat in 2018, led the U.S. House of Representatives spending panel that oversees NASA.
The lack of consensus scientific support, and the fact that a 2025 launch would require the lander to be designed before the Clipper observed the moon’s surface, have been driven by the “unattainable” timeline imposed by Congress, NASA’s Office of Inspector General concluded in a report today. Instead of moving ahead with the lander, the report suggests, NASA should delay the project until it can be considered during the next decadal assessment of NASA’s planetary science, led by the National Academy of Sciences and scheduled for 2022.
In comments included with the report, NASA’s science office in Washington, D.C., led by Thomas Zurbuchen, noted that a reassessment of the lander, conducted last month for planning its 2021 budget request, “resulted in an estimated launch date of no earlier than 2030.” This launch date, it said, would allow time to reduce technical risks and permit the decadal survey to consider the mission. “Technology development will continue as funding allows,” the science office adds. But in the meantime, many of the personnel who had been developing the lander have transitioned to other priorities, the agency said.
For this fiscal year, Congress gave NASA $195 million to spend on developing the lander, with a launch required by 2025. Earlier this year, NASA requested no additional money for the lander in its proposed budget for the 2020 fiscal year, which begins 1 October. With Culberson gone, the new head of science spending in the House, Representative José Serrano (D–NY), did not fully reverse course: Although the 2020 spending bill being considered by the House includes no money for the lander, it directs NASA to include “adequate funding” in its 2021 budget request for continued R&D in support of the lander.
Postponing the lander could benefit the strained workforce at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, which manages both the Clipper and the lander, along with the Mars 2020 rover. JPL has struggled to put enough technical staff on the Clipper project, the inspector general reported: In December 2018, the Clipper workforce was understaffed by 10%, with vacancies in science instruments and avionics. The cost projections for the mission were also overly optimistic, the report says; such cost overruns prompted Zurbuchen to cancel development in March of one instrument, a magnetometer. Instead, the mission will use a cheaper, less capable instrument.
Congress has also mandated that the Clipper use NASA’s Space Launch System (SLS), its long-delayed heavy launch rocket. Using the SLS would allow the Clipper to shoot directly toward Jupiter, arriving 4 years earlier than if launched on a commercial rocket. The agency will struggle to launch the rocket before 2021, the report notes, and it has ordered two missions to Earth’s moon but not a third flight of the rocket. As a result, the report concludes, “We do not see a possibility for Clipper to launch on the SLS by 2023,” as now planned.
In its 2020 budget request to Congress, NASA stated that it would prefer to launch the Clipper on a commercial vehicle, such as the Delta IV Heavy or the Falcon Heavy, which would save $700 million. Now, the Europa Clipper team is keeping options open to fly on the SLS or an alternative rocket. But the mission is coming close to finalizing its designs and starting to build hardware, and it will need certainty by this summer, the report says. “Keeping both the SLS and commercial launch vehicle options beyond [this time] creates added risks and uncertainties for an already challenging project.”