Europa clipper mission update: Preliminary design with selected instruments

Abstract

Europa, the fourth-largest moon of Jupiter, is believed to be one of the best places in the solar system to look for extant life beyond Earth. The 2011 Planetary Decadal Survey, Vision and Voyages [1], states: “Because of this ocean's potential suitability for life, Europa is one of the most important targets in all of planetary science.” Exploring Europa to investigate its habitability is the goal of the proposed Europa Clipper mission. This exploration is intimately tied to understanding the three “ingredients” for life: liquid water, chemistry, and energy. The Europa Clipper mission will investigate these ingredients by comprehensively exploring Europa's ice shell and liquid ocean interface, surface geology and surface composition to glean insight into the inner workings of this fascinating moon. In addition, a lander mission is seen as a possible future step, but current data about the Jovian radiation environment and about potential landing zones that are both scientifically interesting and safe for landing is insufficient. Therefore, an additional goal of the mission is to characterize the radiation environment near Europa and locate and investigate scientifically compelling sites for hazards to inform a potential future landed mission. The Europa Clipper mission will send a Flight System, consisting of a Spacecraft equipped with a payload of NASA-selected scientific Instruments, to execute a large number of Europa flybys while in Jupiter orbit. A key challenge of this mission is that the Flight System must survive and operate in the intense Jovian radiation environment, which is especially harsh near Europa. The innovative design of this multiple-flyby tour is an enabling feature of the Europa Clipper mission: by minimizing the time spent in the radiation environment, the spacecraft complexity and cost has been significantly reduced compared to previous mission concepts. Europa Clipper is planned to launch no earlier than 2022 on a NASA-supplied launch vehicle from Kennedy Space Center (KSC), Cape Canaveral, Florida, USA. The mission is formulated and implemented by a combined Jet Propulsion Laboratory (JPL) and Applied Physics Laboratory (APL) Project team. In January 2017, the Europa Clipper mission passed its System Requirements Review / Mission Definition Review (SRR/MDR), and NASA approved the mission for entry into Phase B (the Preliminary Design phase) in February. The “Clipper” name was officially sanctioned by NASA. The Flight System Preliminary Design Review (PDR) took place in October 2017 and will be followed by Subsystem PDRs and will culminate with Project PDR in August 2018. Mass and power allocations have been made; a new tour trajectory has been designed and adopted, the sizing of key design elements has been determined (propulsion tanks, solar array, etc), and a down-selection to one launch vehicle by NASA is anticipated sometime this year. A decision to down-select to the NASA Space Launch System (SLS) would enable launch onto a direct-to-Jupiter trajectory, allowing significant system simplifications. This paper will describe the progress of the Europa Clipper Mission since January 2017, including maturation of the Flight System design, mission trajectories, requirements, and system analyses.