Scheduled to launch in October 2024, NASA’s Europa Clipper will set out on a journey to explore the habitability of Jupiter’s icy ocean world Europa. After a 5.5 yr cruise that includes gravity assists at Mars and Earth, the spacecraft will enter orbit around Jupiter and will perform nearly 50 flybys of Europa over a four-year period. To explore Europa as an integrated system and achieve a complete picture of its habitability, the Europa Clipper mission has three main science objectives to characterize: (1) the ice shell and ocean including their heterogeneity, properties, and surface–ice–ocean exchange; (2) Europa’s composition including any non-ice materials on the surface and in the atmosphere, and any carbon-containing compounds; and (3) Europa’s geology including surface features and localities of high science interest. Additionally, several cross-cutting science topics will be investigated through searching for any current or recent activity in the form of thermal anomalies and plumes, performing geodetic and radiation measurements, and assessing high-resolution, co-located observations at select sites to provide reconnaissance for a potential future landed mission. These science objectives will be accomplished using a highly capable suite of remote-sensing and in-situ instruments. The remote sensing payload consists of the Europa Ultraviolet Spectrograph (Europa-UVS), the Europa Imaging System (EIS) consisting of a wide and a narrow angle camera (WAC, NAC), the Mapping Imaging Spectrometer for Europa (MISE), the Europa Thermal Imaging System (E-THEMIS), and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The in-situ instruments are the Europa Clipper Magnetometer (ECM), the Plasma Instrument for Magnetic Sounding (PIMS), the SUrface Dust Analyzer (SUDA), and the MAss Spectrometer for Planetary Exploration (MASPEX). Gravity and radio science will be obtained using the spacecraft's telecommunication system, and valuable scientific data will be acquired by the spacecraft’s radiation monitoring system. Assembly, test, and launch operations (ATLO) of the Europa Clipper spacecraft are progressing well, and the flight system integration and environmental testing has been completed at the Jet Propulsion Laboratory. Currently, the flight system is undergoing operations testing, and in May 2024, the spacecraft will be shipped to NASA’s Kennedy Space Center at Cape Canaveral, Florida. There, the remaining integration activities will occur for the solar array and REASON antennas followed by final flight system tests. The launch period begins on 10 October 2024. To provide details on the mission’s instruments and planned investigations, the Europa Clipper science team is publishing manuscripts in a special issue of Space Science Reviews, and the team continues to work towards optimizing science return through preparation of the mission’s Strategic Science Planning Guide. As well, collaborative science opportunities with ESA’s JUpiter ICy moons Explorer (JUICE) mission, which will overlap in its tour period at Jupiter and make observations of Europa, are being discussed informally among the science teams. Onward to Europa!
Encouraging diversity in planetary science requires making a particular effort to bring a broader range of people onto the mission teams that are the backbone of the field. Observer programmes, which offer early-career researchers the chance to embed within a mission team during a science meeting, are one way of doing this. Here we present a quantitative analysis of the effectiveness of two observer programmes: InSightSeers and DART Boarders, linked respectively to the InSight and the Double Asteroid Redirection Test (DART) missions, using a mixture of one-group pre-test/post-test and one-group post-test only evaluation methods, with a total of 56 participants. We find substantial educational value added to participants from both programmes, with particular strengths being the effectiveness of these programmes at providing an introduction to mission teams and international collaborations. This work demonstrates that mission observer programmes can be an effective way of exposing early-career researchers to planetary science missions.
InSight is the first planetary mission with a seismometer package, SEIS, since the Apollo Lunar Surface Experiments Package. SEIS is complimented by APSS, which has as a goal to document the atmospheric source of seismic noise and signals.
Since June 2019, SEIS has been delivering 6 axis 20 sps continuous seismic data, a rate one order of magnitude larger originally planned. More than 50 events have been detected by the end of July 2019 but only three have amplitudes significantly above the SEIS instrument requirement. Two have clear and coherent arrivals of P and S waves, enabling location, diffusion/attenuation characterization and receiver function analysis. The event’s magnitudes are likely ≤ 3 and no clear surface waves nor deep interior phases have been identified. This suggests deep events with scattering along their final propagation paths and with large propagation differences as compared to Earth and Moon quakes.
Most of the event’s detections are made possible due to the very low noise achieved by the instrument installation strategy and the very low VBB self-noise. Most of the SEIS signals have amplitudes of spectral densities in the 0.03-5Hz frequency bandwidth ranging from 10-10 m/s2/Hz1/2 to 5 10-9 m/s2/Hz1/2. The smallest noise levels occurs during the early night, with angstrom displacements or nano-radian tilts. This monitors the elastic and seismic interaction of a planetary surface with its atmosphere, illustrated not only by a wide range of SEIS signals correlated with pressure vortexes, dust devils or wind activity but also by modulation of resonances above 1 Hz, amplified by ultra-low velocity surface layers. After about one half of a Martian year, clear seasonal changes appear also in the noise, which will be discussed.
One year after landing, the seismic noise is therefore better and better understood, and noise correction techniques begun to be implemented, either thanks to the APSS wind and pressure sensors, or by SEIS only data processing techniques. These data processing techniques open not only the possibility of better signal to noise ratio of the events, but are also used for various noise auto-correlation techniques as well as searches of long period signals.
Noise and seismic signals on Mars are therefore completely different from what seismology encountered previously on Earth and Moon.
<p><strong>Introduction</strong>: With a launch readiness date of late 2024, NASA&#8217;s Europa Clipper will set out on a journey to explore the habitability of Jupiter&#8217;s moon Europa. In the early 2030s, the spacecraft will enter Jupiter orbit then fly by Europa nearly 50 times to collect data on Europa&#8217;s ice shell and ocean, study its composition, investigate its geology, and search for and characterize any current activity. The mission&#8217;s science objectives will be accomplished using a highly capable suite of remote-sensing and in-situ instruments.</p><p><strong>Mission Context</strong>: Interpretation of Galileo mission data suggests that Europa likely hides a global saltwater ocean beneath the icy surface. Chemistry at the ice surface and ocean-rock interface might provide the building blocks for life. NASA&#8217;s Europa Clipper mission is intended to assess Europa&#8217;s potential habitability.</p><p>The Voyager and Galileo missions first revealed a deformed surface at Europa with an average surface age younger than Earth&#8217;s, dominated by water ice and renewed through recent or current geologic activity. Galileo data indicates that Europa has an induced magnetic field, implying the presence of a global, electrically conductive fluid layer beneath the surface, most likely a saltwater ocean. Geological data including structural patterns are also consistent with a subsurface ocean. Recent observations also suggest the presence of plumes may release internal water into space, indicating the potential for additional shallow water reservoirs beneath Europa&#8217;s icy surface.</p><p>There are many open questions regarding the viability of Europa to support life. Intense radiation from Jupiter at Europa&#8217;s surface forms water and impurities into oxidants, chemical reagents capable of carrying out oxidation. Active geologic cycling of seawater through rocky material on the Europan seafloor is expected to be chemically reducing. If mixing between the surface oxidants and the reduced ocean water occurs, there is an opportunity in Europa&#8217;s ocean or ice shell to produce a reduction-oxidation (redox) potential. All known life on Earth relies on such redox potentials to extract chemical energy from the environment in exchange for heat energy and entropy, enabling cellular maintenance, metabolism, and reproduction. Europa may have the ingredients that could support life: liquid water, bioessential elements, chemical energy, and a stable environment through time.</p><p><strong>Science Goal and Objectives</strong>: The overarching goal of the Europa Clipper mission is to explore Europa to investigate its habitability. This will be achieved through the accomplishment of three science objectives:</p><ul><li>Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice- exchange.</li> <li>Understand the habitability of Europa&#8217;s ocean through composition and chemistry.</li> <li>Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities.</li> </ul><p><strong>Science Payload</strong>: The remote sensing payload consists of the Europa Ultraviolet Spectrograph (Europa-UVS), the Europa Imaging System (EIS), the Mapping Imaging Spectrometer for Europa (MISE), the Europa Thermal Imaging System (E-THEMIS), and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). The in-situ instruments comprise the Europa Clipper Magnetometer (ECM), the Plasma Instrument for Magnetic Sounding (PIMS), the SUrface Dust Analyzer (SUDA), and the MAss Spectrometer for Planetary Exploration (MASPEX). Gravity and Radio Science (G/RS) will be achieved using the spacecraft's telecommunication system, and valuable scientific data will be acquired by the spacecraft&#8217;s Radiation Monitoring system (RADMON).</p><p><strong>Status and Advancement Toward Launch</strong>: Both the spacecraft and the payload are currently under construction, as the mission begins its assembly, testing, and launch operations (ATLO) phase. Recent major milestones include selection of a launch vehicle and launch readiness date by NASA, evaluation of candidate tours by the science team, and preparations for the cruise and operational phases of the mission. The project, flight system, and payload have completed their Critical Design Reviews, and the project has completed its System Integration Review. Europa Clipper is now formerly a Phase D mission. Meanwhile, the science team is preparing a set of manuscripts describing the mission&#8217;s science and instruments for publication in the journal Space Science Reviews.</p><p><strong>One Team Philosophy</strong>: Our &#8220;One Team&#8221; philosophy prioritizes synergistic science by bridging across the individual instrument-based investigations, while promoting collaborations among members of the Europa Clipper science team. Each of the Europa Clipper individual instruments will be used to investigate Europa and its environs, finding critical clues about how Europa works as a planetary body. In combining and assessing the datasets from each instrument's experiments, we can collectively gain clarity into Europa&#8217;s mysteries. It is at the overlapping boundaries of our subfields that the greatest insights and discoveries will be made. Integrated science celebrates our individual expertise, challenges our assumptions, breaks through our limitations, and expands our intellectual boundaries. Associated visibility brings trust, promotes partnerships, and enhances personal relationships. These aspirations are the inherent basis for functioning as one Europa Clipper science team.</p><p><strong>JUICE-Clipper Coordination</strong>: The JUICE spacecraft is expected to be in the Jovian system at the same time as Europa Clipper, and there is substantial overlap between these missions&#8217; primary phases. The Europa Clipper and JUICE science teams have begun informal collaboration to suggest synergistic science that could be supported on a non-interference basis. The scientific collaborations currently extend across two ad hoc working groups, one on the Galilean satellites and one on Jupiter&#8217;s magnetosphere. Current discussions are to form a joint focus group to advise the two project teams on potential collaborations and &#160; propose a plan for synergistic observations, joint publications, and joint archival data products.</p><p><strong>Acknowledgments</strong>: Portions of this work were performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This work was supported by NASA through the Europa Clipper Project.</p>
Abstract Juno's “Perijove 1” (27 August 2016) and “Perijove 3” (11 December 2016) flybys through the innermost region of Jupiter's magnetosphere (radial distances <2 Jovian radii, 1.06 R J at closest approach) provided the first in situ look at this region's radiation environment. Juno's Radiation Monitoring Investigation collected particle counts and noise signatures from penetrating high‐energy particle impacts in images acquired by the Stellar Reference Unit and Advanced Stellar Compass star trackers, and the Jupiter Infrared Auroral Mapper infrared imager. This coordinated observation campaign sampled radiation at the inner edges of the high‐latitude lobes of the synchrotron emission region and more distant environments. Inferred omnidirectional >5 MeV and >10 MeV electron fluxes derived from these measurements provide valuable constraints for models of relativistic electron environments in the inner radiation belts. Several intense bursts of high‐energy particle counts were also observed by the Advanced Stellar Compass in polar regions outside the radiation belts.
