Energy management operations for the Insight solar-powered mission at Mars

Abstract

NASA's InSight Discovery mission to Mars will land its Phoenix-heritage spacecraft to the near-equatorial Elysium Planitia region of Mars in November 2018 — instead of its original planned landing in September 2016 — to collect science measurements over a period longer than one Mars year. Thus, instead of arriving in mid-Mars-global-dust-storm season in 2016 as originally planned, InSight now will arrive in 2018 during the Martian season when dust storms are typically waning. However, it must be able to withstand a global dust storm near the mission's end a Mars year later, by which point dust on the solar arrays is likely to have accumulated significantly more. This paper discusses how the change in launch date has changed the energy management challenges for InSight, and how the energy management approach for surface operations has been adapted to address those challenges. It also describes how energy balance and battery life are protected over the course of the InSight landed mission, in terms of a deliberate balance between autonomous on-board fault protection and ground commanding into reduced-load configurations that still make progress versus specific, prioritized mission success criteria. It describes the project's unique statistical analysis and usage of Mars Exploration Rovers (MER) archived data on solar energy collection to develop and validate an explicit pre-launch margin policy versus energy reductions due to environment variability over multiple-sol sequences. And finally, the paper explains how this archived energy data has influenced the modification of the Phoenix-heritage autonomous fault protection, to guard against quickly-arising inclement power-generation conditions, such as rapid onset of a local dust storm or water ice cloud front.