WASHINGTON — Despite what a key member of Congress called a “very disappointing” budget request, NASA is taking steps to develop a lander that could accompany an orbiter mission to Jupiter’s icy moon Europa.

In late February, NASA’s planetary science division sent a letter to scientists requesting applications to join a science definition team (SDT) for the proposed lander. The goal of the SDT, the letter stated, is “defining the science objectives and feasibility of specific lander mission concept focused on assessing the habitability of and searching for life on Europa.”

NASA expects to form the SDT later in March, to be followed by a series of teleconferences and face-to-face meetings. The letter doesn’t state when the SDT would complete its work and disband, but the letter does request information on applicants’ availability over the next 12 months.

However, the SDT could complete their work much earlier. “They should be able to get that work done, I would say, by early summer,” said Charles Elachi, director of NASA’s Jet Propulsion Laboratory, at a March 3 hearing of a House appropriations subcommittee on NASA’s “Ocean Worlds” program.

The completion of the SDT report would allow NASA to move ahead on an announcement of opportunity for instruments for the lander to achieve those scientific objectives. “In my mind, earlier is better” for issuing such a call for instrument proposals, Elachi said, noting that, for past missions, it’s taken six to seven years from the time a instrument payload is selected until a mission is ready for launch.

JPL has been carrying out internal studies of a lander, which could accompany a “Europa Clipper” mission that would orbit Jupiter and make multiple close flybys of the moon. The lab hasn’t released details about those lander concepts, but at the hearing Elachi suggested it would make use of technology developed at JPL for Mars landers.

“That lander will capitalize very heavily on what we have done on Spirit, Opportunity and Curiosity,” he said. That includes making use of the “sky crane” technique used for landing Curiosity successfully in 2012. “So we are very confident, technologically, that with appropriate funding that mission could be done at an acceptable risk.”

The lander, Elachi said, would not be attached to the orbiter spacecraft but would be an independent spacecraft, even if the two spacecraft are launched together. Elachi said that even if they are flown together, the orbiter would study Europa first and identify potential landing sites before the lander attempts to set down at one of them.

The issue of appropriate funding, or lack thereof, was an issue the subcommittee’s chairman, Rep. John Culberson (R-Texas), raised at the hearing. “Unfortunately, once again the Office of Management and Budget has given us a 2017 request that cuts the planetary science budget,” he said. “It’s very disappointing and aggravating.”

The 2016 omnibus spending bill provided $175 million to NASA for work on a Europa mission, including a lander, far more than the administration’s request of $30 million. In the 2017 budget request, NASA included nearly $50 million for a Europa mission.

Culberson asked Elachi what level of funding NASA’s planetary sciences program should receive to keep a Europa mission and other programs on track. “That’s a better question to ask NASA,” Elachi responded. “Clearly, it depends on when you want these missions to happen.”

He suggested, though, that the Europa mission will need even more funding than what Congress has granted so far to support a launch in the early 2020s. “If you want to launch in the early ’20s, the present level is not sufficient to do that,” he said.