Europa Clipper

Europa Clipper [NASA]

Europa Clipper is a planned Jupiter orbiter with a focus to conduct detailed reconnaissance of Jupiter's moon Europa and investigate whether the icy moon could harbor conditions suitable for life.

The mission will place a spacecraft in orbit around Jupiter in order to perform a detailed investigation of Europa -- a world that shows strong evidence for an ocean of liquid water beneath its icy crust and which could host conditions favorable for life. The mission will send a highly capable, radiation-tolerant spacecraft into a long, looping orbit around Jupiter to perform repeated close flybys of the icy moon.

NASA’s fiscal year 2016 budget request includes $30 million to formulate a mission to Europa. The mission would send a solar-powered spacecraft into a long, looping orbit around the gas giant Jupiter to perform repeated close flybys of Europa over a three-year period. In total, the mission would perform 45 flybys at altitudes ranging from 25 kilometers to 2,700 kilometers.

NASA has selected nine science instruments for the mission. The selected payload includes cameras and spectrometers to produce high-resolution images of Europa's surface and determine its composition. An ice penetrating radar will determine the thickness of the moon's icy shell and search for subsurface lakes similar to those beneath Antarctica's ice sheet. The mission will also carry a magnetometer to measure the strength and direction of the moon's magnetic field, which will allow scientists to determine the depth and salinity of its ocean. Gravity measurements will also help confirm the existence of Europa’s subsurface ocean.

A thermal instrument will survey Europa's frozen surface in search of recent eruptions of warmer water at or near the surface, while additional instruments will search for evidence of water and tiny particles in the moon's thin atmosphere. NASA's Hubble Space Telescope observed water vapor above the south polar region of Europa in 2012, providing potential evidence of water plumes. If the plumes' existence is confirmed -- and they're linked to a subsurface ocean -- studying their composition will help scientists investigate the chemical makeup of Europa's potentially habitable environment while minimizing the need to drill through layers of ice.

The Europa Clipper rover will carry following instruments:

• Plasma Instrument for Magnetic Sounding (PIMS) developed by the Johns Hopkins Applied Physics Laboratory (APL), Laurel, Maryland. 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.
• Mapping Imaging Spectrometer for Europa (MISE) developed by the JPL. This instrument 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.
• Europa Imaging System (EIS) developed by theAPL. The wide and narrow angle cameras on this instrument will map most of Europa at 50 meter resolution, and will provide images of areas of Europa’s surface at up to 100 times higher resolution.
• Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) developed by the University of Texas, Austin. 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.
• Europa Thermal Emission Imaging System (E-THEMIS) developed by the Arizona State University, Tempe. This “heat detector” 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.
• MAss SPectrometer for Planetary EXploration/Europa (MASPEX) developed by the Southwest Research Institute (SwRI), San Antonio. 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.
• Ultraviolet Spectrograph/Europa (UVS) developed by the 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.
• SUrface Dust Mass Analyzer (SUDA) developed by the University of Colorado, Boulder. 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.
• A magnetometer replacing the cancelled ICEMAG to measure the magnetic field near Europa is planned.

The originally planned Interior Characterization of Europa using Magnetometry (ICEMAG) developed by NASA’s Jet Propulsion Laboratory (JPL), which was to 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, was cancelled in March 2019 due to escalating costs. A less complex version might be added instead.

During the nominal mission, the spacecraft will perform 45 flybys of Europa at closest-approach altitudes varying from 2700 kilometers to 25 kilometers above the surface.

Originally a launch on an Atlas-5(551) was baselined, which would have neccessiated using a Venus-Earth-Earth gravity assist trajectory with the transit time to Jupiter would have been about six years. Later the baseline was changed to a SLS (Block 1B) EUS, which would allow for a direct trajectory in less than three years. Alternatively a launch on a SLS (Block 1) iCPS is possible

Launch is planned in the 2022-2025 timeframe. The spacecraft is to be completed in 2023, delayed to 2024. There are launch opportunities in the summer and fall of 2024 for the mission, including an August launch window using SLS (Block 1) iCPS that would send the spacecraft directly to Europa. An October launch window would require Mars and Earth gravity assists, extending the flight time, but could also be done by commercial launch vehicles such as SpaceX’s Falcon-Heavy (Block 5). In February 2021, NASA decided not to use SLS to launch Europa Clipper. In July 2021, a Falcon-Heavy (Block 5)(ex) was selected for a launch in October 2024.