Efficient Science Return at Europa: Advance Operations and Science Planning for the Europa Lander Mission

Jupiter’s moon Europa is a prime target in our exploration of potentially habitable worlds and of ocean worlds in the outer solar system.  Europa’s subsurface ocean has likely existed for much of the history of the solar system and may provide a persistent, stable environment rich in the elements and energy needed for life.  The ocean is likely in contact with a rocky, silicate seafloor.  And, tectonic activity in the ice shell may allow oxidants produced at the surface via radiolysis to cycle into the ice shell and ocean below.  All of these factors make Europa exploration key for both astrobiological and comparative oceanography goals.

 

Europa Lander is a mature mission concept that has brought together the expertise of scientists and engineers, across NASA centers, ESA centers and industry, who have extensive experience in both Outer Planets missions and landed Mars missions.  A highly capable, partially autonomous lander weighing in excess of approximately 500 kg, would excavate into the Europan surface to directly acquire samples.  The high-level science goals of Europa Lander are: (1) search for evidence of biosignatures on Europa, (2) assess the habitability of Europa via in situ techniques uniquely available to a lander and (3) characterize surface and subsurface properties of the ice shell.  The lander would collect and process ≥3 separate samples, each at least 7 cm³ in volume, acquired from a depth of ≥10 cm.  Using primary batteries, a lander could operate for 60 days or more on the surface.

 

To maximize the efficiency of the Lander and get the very best science from such a mission, the Europa Lander team has invested a significant amount of time and effort to study how the mission could operate on the surface.  The mission could utilize a high degree of autonomy to continually sample the surface, process samples with the instrument payload, and relay data back to Earth.  However, getting the most from this autonomy requires efficient interaction with the science and operations teams on the ground.  The Europa Lander team has held multiple evaluations, called design simulations, that have explored how human scientists and engineers would interact with an autonomous spacecraft and respond to the discoveries that it makes as the mission unfolds.  Groups of scientists and engineers, including members of the Europa Lander pre-project team, as well as people unaffiliated with the pre-project, worked through multiple scenarios, including the detection of nominally positive biosignatures, issues related to sampling arm access to tight spaces, and end-of-life decisions.  Lessons learned during the simulations could help inform the operations team and serve to maximize science return.

 

Likewise, the team has explored how physical constraints imposed by the environment and by the spacecraft itself could impact scheduling details.  These constraints include, but are not limited to, the length of the Europan night (42.5 hours), limited downlink bandwidth, thermal constraints on the spacecraft and battery life.  The team investigated multiple conops scenarios to develop detailed, realistic timelines that depict all facets of spacecraft surface operations -- including uplink and downlink, sample excavation and transfer, data analysis, and even spacecraft-imposed sleep cycles -- under a variety of assumptions regarding the capabilities of the notional spacecraft and payload.  The detailed strawman timelines that the team has produced convincingly demonstrate the feasibility of collecting, processing, and returning data from at least 6 samples, and possibly as many as 11 or more, to investigate Europa's habitability and search for biosignatures.

 

In this presentation, we will describe the detailed work by the Europa Lander team that will help enable Europa Lander science planning and operations to work seamlessly with an autonomous spacecraft in a unique environment.

 

This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Copyright: 2022. All rights reserved.