Balancing cost and science: NASA examines less expensive mission design for Europa lander

Artist’s conception of the Europa lander. Image Credit: NASA/JPL-Caltech

The push for a return mission to Jupiter’s moon Europa has been gaining steam in the last few years, with NASA now planning for Europa Clipper, which would make repeated close flybys to study the moon’s interior ocean and the exciting potential for life. There has also been more talk about a possible lander to examine the moon’s surface up close. Such a mission would be expensive of course, but NASA is now studying possible ways to lessen the costs while maintaining good science return.

On Sept. 6, 2017, Curt Niebur, a program scientist in the planetary science division at NASA Headquarters, told a meeting of the Outer Planets Assessment Group (OPAG) that NASA is examining the mission design, taking into account both mission costs and the potential science return.

“As a result of that mission concept review, what we want to do is essentially continue exploring the different options we have for a Europa lander mission,” said Niebur. “We want to continue balancing the trade amongst risk, cost and science return.”

Some earlier ideas had proposed a combined clipper/lander, but the costs would be prohibitive and also require as-yet unused technology. The thinking now is to have a lander as a separate mission, following Europa Clipper. Earlier this year, the updated proposal calls for the lander to be launched on a Space Launch System (SLS) rocket no earlier than late 2025, which would arrive at Jupiter in mid-2030 and land on Europa in late 2031. Five instruments would be used to analyze material on the surface and the battery-powered probe would be able to operate for about 20 days. A possible downside is that lower costs would mean less science being done.

Illustration of Europa’s possible water vapor plumes. Image Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center/Z. Levay (STScI)
Close-up view of Europa’s icy, cracked surface as seen by the Galileo spacecraft in 1996. Image Credit: NASA/JPL/University of Arizona
Below Europa’s cold, icy surface lies a deep, salty liquid water ocean which could be home to some form of life. Image Credit: Britney Schmidt/Dead Pixel VFX/Univ. of Texas at Austin

“I firmly believe that you can’t make substantial cost reductions and maintain the full science return of this mission,” he said. “If you really want to see a more streamlined mission concept, you’re going to have to be willing to give up some science. So, yes, science is on the table.”

As of right now, no firm decisions have been made and NASA has not yet released an Announcement of Opportunity (AO) for instruments to be included.

“Until we finish that exploration, it’s premature to release an AO,” Niebur said.

Meanwhile, progress is being made on Europa Clipper and it has now entered a preliminary design phase, including science instruments, bringing it much closer to being a reality than the lander so far.

Before the lander mission, NASA is planning the Europa Clipper, which would make repeated close flybys of the moon in the 2020s. Image Credit: NASA/JPL-Caltech

“This is supremely great news,” said Niebur in a Feb. 22 presentation at another meeting of the Outer Planets Assessment Group (OPAG) in Atlanta.

Current plans are for Europa Clipper to launch “in the early 2020s” although recent appropriations bill funding has directed NASA to launch the mission by 2022.

With the recent ending of the incredible Cassini mission at Saturn, a return to Europa, last seen up close by the Galileo probe in the early 2000s, would be exciting indeed. Apart from Juno currently at Jupiter, but only studying the planet itself, there are currently no other outer Solar System planetary missions being designed yet, although tentative ideas are in the works for a return to Enceladus and Titan as well, as part of the Ocean Worlds program. After Cassini, there will still be a long gap in exploration of this region of the Solar System however. Hopefully both the Europa Clipper and lander missions will be able to help fill that gap.

This article was first published on AmericaSpace.





A new look at ‘ocean worlds’: James Webb Space Telescope will target Europa and Enceladus

An example of possible spectroscopy results from one of Europa’s water vapour plumes. Image Credit: NASA-GSFC/SVS/Hubble Space Telescope/Stefanie Milam/Geronimo Villanueva

NASA’s upcoming James Webb Space Telescope (JWST) will be used to study two of the most fascinating moons in our Solar System  – Europa and Enceladus, also known as “ocean worlds” since both have global oceans of water beneath their outer icy surfaces. The new observations will help scientists learn more about conditions on these worlds and guide the development of future robotic missions.

Both moons are exciting targets since Europa’s surface has deposits of minerals thought to have come up from the ocean below, and Enceladus has huge plumes of water vapour erupting through fissures in the icy surface, originating from the subsurface ocean. Europa may also have plumes, which have been tentatively identified but not confirmed yet. Enceladus’ plumes also contain organic compounds of various complexities, which were sampled directly by the Cassini spacecraft multiple times.

“We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest,” said astronomer Heidi Hammel, executive vice president of the Association of Universities for Research in Astronomy (AURA).

Astronomers will use Webb’s near-infrared camera (NIRCam) to take high-resolution images of Europa’s surface, to search for hot regions related to plumes and active geological processes. If a plume is found, they can then use Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI) to analyze the plume’s composition.

“Are they made of water ice? Is hot water vapour being released? What is the temperature of the active regions and the emitted water?” asked Villanueva. “Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.”

JWST will be able to study Enceladus’ plumes and surface in a similar manner, even though it is about 10 times smaller than Europa as seen by the telescope.

For both moons, a focus will be to search for organic signatures such as methane, methanol, and ethane in the plumes. Evidence of life itself, like microbes, would be more difficult since some life-like processes could also have a geological explanation.

Composite image showing the possible water vapour plumes near the south pole of Europa, at about the 7 o’clock position. The image of Europa, from the Galileo and Voyager missions, is superimposed on the Hubble data. Image Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center
Diagram of an interior cross-section of the crust of Enceladus, showing how hydrothermal activity is thought to be causing the plumes of water vapour on the surface. Image Credit: NASA-GSFC/SVS/NASA/JPL-Caltech/Southwest Research Institute
The water vapour plumes of Enceladus, as seen by the Cassini spacecraft. Photo Credit: NASA/JPL-Caltech

“We only expect detections if the plumes are particularly active and if they are organic-rich,” Villanueva noted.

JWST is the successor to the Hubble Space Telescope (HST) and will be the most powerful space-based telescope ever built. It is an international project led by NASA, along with the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Even if JWST isn’t able to find signs of life on either moon, it will be another huge step in understanding what conditions are like, both on their surfaces and below the ice in the oceans themselves, building on results from spacecraft such as Galileo and Cassini. It will help prepare the way for future, more advanced probes on the drawing boards now which may be able to answer that question of whether life has ever existed on (in) these far-off ocean worlds.

This article was first published on AmericaSpace.









Joint NASA/ESA mission proposed to search for life on Europa

Ocean world: new proposed mission would search for evidence of life in Europa’s subsurface water ocean. Photo Credit: NASA/JPL/Ted Stryk

Europa is one of the most fascinating places in the Solar System, and is considered to be at or near the top of the list of worlds to search for possible evidence of life. Beneath its outer ice crust lies a deep and dark salty ocean, thought to be quite to Earth’s own oceans. Could that ocean be inhabited, even if just by microbes? Scientists want to know, and now a new proposal calls for a joint orbiter/lander mission between NASA and ESA (European Space Agency), to try to answer that question.

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New findings from two ‘ocean moons’ increase possibility of finding alien life

Illustration of the Cassini spacecraft flying through the water vapour plumes of Enceladus. Image Credit: NASA/JPL-Caltech

For those who are hoping to find evidence of life somewhere else in the Solar System, there was some exciting news this week. Two moons, Europa and Enceladus, were already thought to be among the best places to search, since both have liquid water oceans beneath their outer icy shells. And now, new data from the Cassini spacecraft and the Hubble Space Telescope has increased the potential for some form of living organisms to be found.

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NASA’s new Europa mission formally named ‘Europa Clipper’

Artist’s conception of Europa Clipper during a flyby of Europa. Image Credit: NASA/JPL-Caltech

It’s been a long time coming, but NASA’s new mission to Jupiter’s moon Europa now has a formal name: Europa Clipper. The spacecraft, to be launched in the early 2020s, will conduct multiple close flybys of the moon, with the goal of determining just how habitable it actually is. With a global salty ocean just beneath its icy crust, Europa is thought to be one of the best places in the Solar System to search for possible alien life.

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