WASHINGTON — NASA announced the selection of nine instruments it plans to fly on a mission to Jupiter’s moon Europa May 26, but agency officials were vague about whether the instruments, or the overall mission, could meet an aggressive schedule sought by some in Congress.

NASA said the nine instrument concepts, selected from 33 proposals submitted by scientists last year, will be flown together on a spacecraft with the goal of determining whether Europa can support life, although not necessarily if the icy moon hosts life today.

“All of these instruments are designed to increase our rather limited knowledge of Europa,” said Curt Niebur, Europa program scientist at NASA Headquarters, during a briefing about the instrument selection. “They’re doing that by helping us probe the big question, which is, ‘Is Europa habitable?’”

The nine instruments include cameras to provide high resolution images of the moon’s surface, magnetometers to measure the depth and salinity of the moon’s subsurface ocean, a radar to probe Europa’s icy crust, and spectrometers to determine the composition of the surface as well as material ejected by plumes.

In addition to the nine instruments chosen for the mission, NASA selected a tenth instrument, a mass spectrometer, for additional technology development. This instrument will not be flown on the mission but will instead be developed for potential use on other spacecraft.

Niebur said NASA anticipates spending about $10 million on the instruments in the next year, and $110 million over the next three years. “That will get us to a key decision point where we decide if we’re going to continue on with the instruments,” he said, as well as calculate a full cost estimate for the instrument suite.

The mission the instruments would fly on is still in its earliest phases of development. “Now that we’ve made the selection of the instruments, we’re going to begin their accommodations on the mission concept,” said Jim Green, director of NASA’s Planetary Science division.

That mission will likely be based on a concept that has been under study at the Jet Propulsion Laboratory known as Europa Clipper. In that mission, the spacecraft would go into orbit around Jupiter and make dozens of flybys of Europa, a less expensive approach than going directly into orbit around the moon. Green said the Europa mission should enter its formulation phase by Oct. 1, the start of the U.S. government’s 2016 fiscal year.

Europa Clipper. Credit: NASA/JPL-Caltech
Europa Clipper. Credit: NASA/JPL-Caltech

Although work on the mission is just beginning, NASA said they selected the instruments now because they typically have long development schedules. “We wanted to get a head start on the instruments as they’re often the long poles in the development of something as complex as a mission to Europa,” John Grunsfeld, NASA associate administrator for science, said at the briefing.

NASA’s announcement comes as the agency is facing new pressure from Congress to accelerate the mission’s schedule. While NASA sought $30 million for the mission in its fiscal year 2016 budget request in February, a spending bill approved by the House Appropriations Committee May 20 provides $140 million for the mission, and also requires the mission to launch no later than 2022, using the Space Launch System heavy-lift rocket.

NASA officials hedged when asked if the instruments, or the mission itself, could meet that schedule. “They could be ready in the early 2020s,” Niebur said of the selected instruments, “but that’s also dependent upon how much money is in the budget for us to give them for that work.”

“We expect it to be launched in the 2020s,” Green said of the mission. “Whether it’s mid, or a little early or a little later, needs to be worked out based on a much firmer cost estimate and a profile that would support it.”

Niebur emphasized that the goal of the mission, whenever it is launched, is to determine whether Europa could support life, not to detect life itself. “We don’t have a ‘life detector,’” he said. “We currently don’t even have consensus among the scientific community as to what we would measure that tell everybody with confidence that this thing you’re looking at is alive.”

Green, though, said he knew what he would do if the mission somehow detected life on Europa. “I would immediately retire,” he said.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...