NASA selects the Instruments for the first dedicated mission to Explore the Water World Europa
by T. Reyes
NASA took a crucial step today towards the launch of the first dedicated mission to the study the Jupiter’s Galilean moon Europa. A suite of scientific instruments have been selected around which the space probe will be built. It always begins with a concept for the mission with some high level design constraints that limit what you can send flying the 250 million miles to the Jovian system. The selection of the nine instruments from institutes across the US. represents the start of the mission formulation.
The NASA panelists presented a series of slides and explanations that described the process and selection of the instrument suite for a mission. The Europa mission is thus far expected to launch in the mid to late 2020s.
Call it “Europa or Bust” for now because the Europa mission is not yet named but it is a mission that will spend 2 ½ years exploring the second of the four Galilean moons first seen by Galileo 405 years ago. This mission concept has certainly drawn upon concept work JPL has completed on Europa Clipper.
The panelists emphasized the amazing and enigmatic terrain that is Europa’s surface. There are regions called “chaotic” that includes icebergs frozen in place. Across the surface, fissures and ridges fragmented that, as they stated, can be reset into place like pieces of a jig-saw puzzle. And underlying all of this surface is an ocean that estimated to be 100 km (62 miles) thick, a volume of water many times greater than Earth’s oceans.
Additionally, analysis of the Chaos regions and comparison to regions in the polar areas of the Earth has led to hypotheses that lakes exist that cause the chaotic terrain and potentially also plumes. A presentation was delivered by Britney Schmidt from UT/Austin at the SETI Institute in October 2012 on the topic [presentation video link]
Normally, NASA uses a two phase selection process but with funding of the “Icy Worlds” program, teams have been already at work. Each of the nine instrument types had at least one or more instruments “ready to go” so a two phase selection was not necessary.
Asked about cost, James Green could provide only a rough estimate — $2 Billion without launch vehicle. This is effectively a NASA Flagship mission by cost. Asked about launch vehicle, the panelists were non-committal, only stating that it will use a conventional chemical propulsion system. Both SLS and Falcon Heavy have been considered for this type of Europa mission.
The space probe will be solar power driven and therefore build upon experience from the solar-powered JUNO mission approaching Jupiter now. Additionally, the experience JUNO delivers from its many flights through the hazardous energetic magnetic field of Jupiter will be used to safeguard the instruments and avionics of this future mission. This mission is likely to require even more solar panel than JUNO which carries 60 square meters (650 sq ft).
In fielding reporter questions, it was emphasized that a life detection instrument does not yet exist for any mission but this instrument suite will determine the habitability of Europa’s interior ocean. The ocean is not isolated from the harsh environment of space and from Jupiters magnetic field environment. Radiation could play a significant role in the chemical compostion and acidic levels of the ocean. Heat produced from tidal forces, the same that liquifies the oceans, is believed to make the ocean temperature in the range of 50 degrees Fahrenheit.
Here are the nine instruments selected:
1. Plasma Instrument for Magnetic Sounding (PIMS), Dr. Joseph Westlake of Johns Hopkins Applied Physics Laboratory (APL), Laurel, Maryland.
2. Interior Characterization of Europa using Magnetometry (ICEMAG), principal investigator Dr. Carol Raymond of NASA’s Jet Propulsion Laboratory (JPL), Pasadena, California.
The two magnetic field instruments will work together to deduce the interior structure of the icy moon. As was just released from analysis of decades old Galileo magnetic field data from flybys of Ganymede, the interior structure of Europa can be deduced from the perturbations in the local magnetic field measured during each flyby. At present, 45 flybys are planned. Ice thickness, ocean depth and salinity can be determined.
3. Mapping Imaging Spectrometer for Europa (MISE), principal investigator Dr. Diana Blaney of JPL.
While none of the instruments are designed to directly detect life, this imaging spectrometer will be able to measure the distribution of organics, salts and other hydrates, water ice phase and other compounds. This spectrometer will likely give the first tantalizing indications of the habitability of the interior ocean.
4. Europa Imaging System (EIS), principal investigator Dr. Elizabeth Turtle of APL.
Only 11% of the surface of Europa has been imaged at a resolution of 200 meters (~650 feet); the Galileo mission. Over 45 planned flybys, the EIS cameras will map Europa at a resolution of 50 meters (164 feet) and will image specific areas at a resolution of approximately 1 1/2 foot resolution.
5. Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON), principal investigator Dr. Donald Blankenship of the University of Texas, Austin.
As depicted in illustrations of the Europa Clipper concept mission, the space probe will sport an expansive antenna system designed to probe the subsurface. REASON is a dual-frequency ice penetrating radar instrument that will characterize and sound Europa’s icy crust from the near-surface to the ocean.
6. Europa Thermal Emission Imaging System (E-THEMIS), principal investigator Dr. Philip Christensen of Arizona State University, Tempe.
This imager in the infrared will detect hot spots but as emphasized by Europa Program Scientist Curt Niebur, hot spots is a relative term. The surface has a mean temperature of -160 C (-256 F). Nonetheless, hot spots discovered could point to the locations of vents that are erupting plumes of water from the subsurface ocean or lakes.
7. Ultraviolet Spectrograph/Europa (UVS) — principal investigator Dr. Kurt Retherford of SwRI.
This instrument will adopt the same technique used by the Hubble Space Telescope to detect the likely presence of water plumes erupting from Europa’s surface. UVS will be able to detect small plumes and will provide valuable data about the composition and dynamics of the moon’s rarefied atmosphere.
8. MAss SPectrometer for Planetary EXploration/Europa (MASPEX), principal investigator Dr. Jack (Hunter) Waite of the Southwest Research Institute (SwRI), San Antonio.
There are plans to impact the surface of the moon to send samples hurtling into space. This instrument will be able to measure the atomic and molecular composition of such excavated gaseous debris. The instrument shares a legacy with a long line of mass spectrometers going back to the 1980s — Dynamics Explorer missions. Asked about how it compares to Cassini’s instrument, the response was “state of the art and very advanced. This instrumen blows everything else out of the water.”
9. SUrface Dust Mass Analyzer (SUDA), principal investigator Dr. Sascha Kempf of the University of Colorado, Boulder.
Complementing the mass spectrometer MASPEX, this instrument will measure the composition of small, solid particles ejected from Europa, providing the opportunity to directly sample the surface and potential plumes on low-altitude flybys.
James Green emphasized that the selection process is a first step in the mission formulation. Formulation will begin in earnest later this year. This year, $10 million is committed to instrument development but $110 million is planned for a following 3 year period after which a full cost estimate will be in hand for this mission planned for the 2020s.
Other recent stories by T.Reyes:
Rosetta and its comet is just 80 days out from Perihelion
New Horizons’ success at Pluto: Its all about Ralph and Alice! “Someday Alice!” … that day is less than 2 months away — the flyby of Pluto and Pluto’s moon Charon
The Singularity can explain why we seem alone in the Universe
The Prelude to the Singularity — our relation with past & present technology foreshadows what could become of us with emergence of artificial super-intelligence
Will We First Find Simple or Intelligent Life beyond the Earth?
