Report lays out science case for Europa lander


WASHINGTON — NASA could launch a mission to land on Jupiter’s moon Europa as soon as 2024 to look for evidence of past or present life on the icy world, a new report concludes.

A report released Feb. 8 by a NASA-chartered science definition team (SDT) concludes that a lander equipped with a suite of five instruments could achieve several major goals during a three-week mission on the moon’s surface.

The report identified three main goals for the proposed lander mission. The first is to look for evidence of past or present life on the surface or just beneath it. The second is to assess whether Europa is habitable, regardless of whether the spacecraft is able to detect any evidence of past or present life. A third goal would be to characterize the properties of the Europan surface to support future missions.

“Europa may hold the clues to one of NASA’s long standing goals — to determine whether or not we are alone in the universe,” the report stated. “The highest-level science goal of the mission presented here is to search for evidence of life on Europa.”

To achieve those goals, the report identified a payload of instruments that would fit on the lander. They include an organic composition analyzer to look for evidence of organic materials, a microscope to look for microbial cells, and a spectrometer to characterize organic and inorganic compounds. The lander would also carry color stereo cameras and a seismic instrument. Supporting those instruments is a system to collect samples from the surface and to a depth of up to 10 centimeters below it.

The mission, as currently designed, would launch as soon as 2024 on a Space Launch System rocket. “Due to the large spacecraft mass at launch, the Space Launch System (SLS) launch vehicle is likely required to provide sufficient performance and is expected to be available by 2024,” the report states, not listing the estimated mass of the entire spacecraft.

A specific trajectory listed in the report specified a launch in October 2025, with an Earth gravity assist in December 2027. The spacecraft would then enter Jupiter orbit in July 2030.

The spacecraft would then spend more than 18 months in orbit around Jupiter, using a series of gravity-assist flybys of the moons Ganymede and Callisto to adjust its orbit for arrival at Europa. The lander then separates from a separate orbiter spacecraft and lands using a “skycrane” system similar to the Curiosity Mars rover, an approach than minimizes the contamination of the landing site by exhaust from the lander’s engines.

Once on the surface, the lander would operate for a mission of 20 days under battery power, communicating with the orbiter, which then relays the data the lander collects back to Earth. The short lifetime, driven by the strong radiation environment in the vicinity of Europa, allows the lander to use batteries rather than large solar arrays or a nuclear power source.

NASA has yet to commit to flying a lander mission, saying previously that it would wait to see if this study would provide a feasible mission concept. “We’re interested in a mission, but we don’t know if a worthwhile mission is possible given the constraints we’re under,” said Curt Niebur, the mission’s program scientist at NASA Headquarters, at an August meeting while the SDT was still working on its report.

The mission, though, has a powerful congressional patron in Rep. John Culberson (R-Texas), chairman of the House appropriations subcommittee that funds NASA. He has provided funding for an orbiter mission, widely known as Europa Clipper, far above NASA requests in recent years, and later started pushing NASA to fly a lander mission as well.

“There’s almost certain to be life in that ocean,” Culberson said in a Feb. 7 speech at a Space Transportation Association luncheon here, referring to the subsurface ocean of liquid water Europa likely harbors. “I’m convinced that that mission will result in the discovery of life in that ocean.”