NASA has announced the selection of science instruments for the Europa Clipper, a future mission to Jupiter’s moon Europa.
Based on new evidence from Jupiter’s moon Europa, astronomers hypothesize that chloride salts bubble up from the icy moon’s global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter’s innermost large moon, Io. Image credit: NASA / JPL-Caltech.
Although Europa and Jupiter’s other moons have been visited by other spacecraft, they were each limited to a single distant flyby.
NASA’s Galileo spacecraft, launched in 1989, was the only mission to make repeated visits to Europa, passing close by the moon less than a dozen times.
Previous studies point to the existence of a liquid water ocean located under the icy crust of Europa. This ocean covers the moon entirely and contains more liquid water than all of Earth’s oceans combined.
Any mission to Europa must take into account the harsh radiation environment that would require unique protection of the spacecraft and instruments. In addition, spacecraft must meet planetary protection requirements intended to protect Europa’s potentially habitable ocean.
NASA’s fiscal year 2016 budget request includes $30 million to formulate a mission to Jupiter’s icy moon that will launch in the 2020s.
The mission would send a solar-powered spacecraft, dubbed Europa Clipper, into a long, looping orbit around the gas giant to perform repeated close flybys of Europa over a three-year period. In total, the mission would perform 45 flybys at altitudes ranging from 16 miles to 1,700 miles (25 km to 2,700 km).
In July 2014, NASA invited scientists to submit proposals for scientific instruments to study the icy moon.
33 proposals were received and, of those, nine were selected for the Europa Clipper.
The payload of selected instruments includes cameras, spectrometers, an ice penetrating radar, a magnetometer, thermal and other instruments:
1. SUrface Dust Mass Analyzer (SUDA): this instrument will be used to measure the composition of solid particles released from Europa’s surface due to meteoroid bombardment. It also will be able to measure the properties of small, solid particles believed to be spewing from a hidden ocean within the moon.
2. Europa Imaging System (EIS): the wide and narrow angle cameras on this instrument will map most of Europa at 164 foot (50 m) resolution, and will provide images of areas of Europa’s surface at up to 100 times higher resolution.
3. Europa Thermal Emission Imaging System (E-THEMIS): this instrument will provide high spatial resolution, multi-spectral thermal imaging of Europa to help detect active sites, such as potential vents erupting plumes of water into space.
4. Plasma Instrument for Magnetic Sounding (PIMS): this instrument works in conjunction with a magnetometer and is key to determining Europa’s ice shell thickness, ocean depth, and salinity by correcting the magnetic induction signal for plasma currents around Europa.
5. Interior Characterization of Europa using Magnetometry (ICEMAG): this magnetometer will measure the magnetic field near Europa and – in conjunction with the PIMS instrument – infer the location, thickness and salinity of Europa’s subsurface ocean using multi-frequency electromagnetic sounding.
6. Mapping Imaging Spectrometer for Europa (MISE): this spectrometer will probe the composition of Europa, identifying and mapping the distributions of organics, salts, acid hydrates, water ice phases, and other materials to determine the habitability of Europa’s ocean.
7. Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON): this dual-frequency ice penetrating radar instrument is designed to characterize and sound Europa’s icy crust from the near-surface to the ocean, revealing the hidden structure of Europa’s ice shell and potential water within.
8. MAss SPectrometer for Planetary EXploration/Europa (MASPEX): this instrument will determine the composition of the surface and subsurface ocean by measuring Europa’s extremely tenuous atmosphere and any surface material ejected into space.
9. Ultraviolet Spectrograph/Europa (UVS): this instrument will adopt the same technique used by the NASA/ESA 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.
Separate from the selectees listed above, the SPace Environmental and Composition Investigation near the Europan Surface (SPECIES) instrument has been chosen for further technology development.
