Europa Clipper: Cubesats But No Nuclear Power

Artists Concept: Image CredIt JPL

One recurring theme in coverage from Innerspace.net is a lamentation over the lack of any flagship class outer planet mission to follow in the wake of the spectacularly successful Cassini/Huygens mission to Saturn. While Innerspace is predominately focused on human exploration and settlement, and in particular the contributions being made by NewSpace companies, sometimes nothing fires the imagination like the surprise coming from new and unexpected discoveries. In this regard, Cassini has been magnificent. And while some would like to see a follow on mission as soon as possible, Jupiter’s enigmatic moon Europa is currently the focus of much of the space science community.

NASA is now in the pre-planning stages of a mission to Jupiter’s most famous moon, Europa Clipper, and although it has yet to receive a full go ahead, appears increasingly likely to come together. Last week’s International Astronautical Congress in Toronto brought several items regarding the mission into the news.

First in a story reported in Space News, word came that the mission will be solar powered.

“In an Oct. 3 presentation at the 65th International Astronautical Congress here, Europa Clipper deputy project manager Thomas Magner of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said that using large solar panels for the mission was both technically viable and less expensive than a radioisotope thermoelectric generator (RTG).

“For the last two years, we did extensive risk reduction work looking at whether solar is feasible,” Magner said. “We found that solar works fine, so our final decision about two months ago was to go to solar.”

As the story points out, the decision does not set a precedent, as the Juno mission, currently en route to Jupiter for a planned 2016 arrival is solar powered as well. While solar will may very well meet the mission objectives, it is also true a major contributing factor is the reality that the United States has seriously dropped the ball in securing adequate production of the PU-238 plutonium pellets which power the nuclear RTG’s needed for more demanding deep space missions. For a nation which professes to (and does) lead the world in deep space exploration, the PU-238 issue continues to be a terribly disappointing failure which will take years to correct, if indeed it ever is.

On another possibly ominous note, while the Europa Clipper would not lift off until 2022 at the earliest, and having yet to be approved does not require a launch vehicle,  planners are keeping open the possibility of using the Space Launch System.

From the same piece:

“An alternative approach would use NASA’s still-in-development Space Launch System heavy-lift rocket to send Europa Clipper on a direct trajectory to Jupiter. A mid-2022 launch would allow the spacecraft to reach Jupiter in fewer than three years, without the need of any flybys.

Launching on SLS, Magner said, would reduce the costs of operating Europa Clipper given the much shorter travel time to Jupiter, and also simplify the thermal design since the spacecraft would not have to perform a Venus flyby in order to reach Jupiter. However, it was unclear how much more Europa Clipper would have to pay for an SLS launch.”

While there is definite merit in looking for faster means to reach the outer planets than afforded through time consuming planetary flybys, which can add years to a mission, a fuller examination of other options might be in order.  It has been clear for some time that desperately searching to find uses for SLS, just as it was with Shuttle prior to 1986, NASA might very well be putting the same set of blinders on.

Somewhat ironically, the other news item related to Europe Clipper comes from the Jet Propulsion Laboratory and regards the use of cubesats for enhancing the mission.

From the JPL News Story:

“NASA’s Jet Propulsion Laboratory in Pasadena, California, has chosen proposals from 10 universities to study CubeSat concepts that could enhance a Europa mission concept currently under study by NASA. The CubeSat concepts will be incorporated into a JPL study describing how small probes could be carried as auxiliary payloads. The CubeSats would then be released in the Jovian system to make measurements and enhance our understanding of Jupiter’s moon Europa.

CubeSats are small, lightweight and low-cost satellites, often only inches on a side. With support from NASA, JPL is working to include small spacecraft on deep space exploration missions to complement primary spacecraft.

The conceptual Europa mission, called Europa Clipper, would conduct detailed reconnaissance of the icy moon and investigate whether it could harbor conditions suitable for life.

Awardees will receive up to $25,000 each to develop their CubeSat concepts for inclusion in the study, which will be completed next summer.

CubeSat concepts from the following universities were chosen by JPL’s Planetary CubeSat office for inclusion in the study:

— Arizona State University, Tempe

— Georgia Tech Research Corporation, Atlanta

— Stanford University, Stanford, California

— The Regents of New Mexico State University, Las Cruces, New Mexico

— The Regents of the University of Colorado, Boulder

— The Regents of the University of Michigan, Ann Arbor

— University of Alaska, Fairbanks

— University of Southern California, Los Angeles

— University of Illinois, Urbana

— University of Washington, Seattle

The universities’ Europa science objectives for their CubeSats would include reconnaissance for future landing sites, gravity fields, magnetic fields, atmospheric and plume science, and radiation measurements.

“We’ve seen some innovative and quite creative surprises among the CubeSat ideas submitted by these universities,” said Barry Goldstein, pre-project manager for the Europa Clipper mission concept. “Using CubeSats for planetary exploration is just now becoming possible, so we want to explore how a future mission to Europa might take advantage of them.”