EscaPADE

Description

The Escape and Plasma Acceleration and Dynamics Explorers (EscaPADE) are a dual-spacecraft mission to study ion and sputtered escape from Mars. The two identical spacecraft were scheduled for launch as secondary satellites on the Psyche mission in August 2022, but were removed due to problems with the required trajectory. A new launch opportunity is to be determined, probably as rideshares in 2024. The science goals of the mission are to: understand the processes controlling the structure of Mars' hybrid magnetosphere and how it guides ion flows; understand how energy and momentum are transported from the solar wind through Mars' magnetosphere; and understand the processes controlling the flow of energy and matter into and out of the collisional atmosphere. EscaPADE is part of the NASA Small Innovative Missions for Planetary Exploration (SIMPLEx) program.

Each identical EscaPADE spacecraft has a mass under 90 kg. The spacecraft bus is 60 x 70 x 90 cm. The spacecraft is powered by two 480 x 70 cm solar panel wings extending from opposite sides of the spacecraft. These charge batteries and power the solar-electric propulsion system. Cold gas thrusters are used to maintain orientation. Communications are in X-band via a 60 cm diameter dish antenna. A 90 cm boom extends above the spacecraft holding some of the science instruments.

There are three science experiments onboard each spacecraft, EMAG, EESA, and ELP. EMAG is a magnetometer that will measure DC magnetic fields up to 1000 nT, mounted at the end and partway up the boom. EESA is an electrostatic analyzer designed to measure suprathermal ions from 2 eV to 20 keV and suprathermal electrons from 3 eV to 10 keV. It is mounted on the upper deck of the spacecraft bus. ELP is a Langmuir probe measuring plasma density from 20 - 30,000 particles per cubic cm and solar EUV flux from 5 - 20 milliwatts per square meter, and is mounted on the boom and on the spacecraft bus.

After launch (probably as a secondary satellite, date to be determined), EscaPADE will reach Mars and go into a highly elliptical orbit. Over roughly the next two years the orbit will be lowered and circularized until it reaches the nominal science orbit. The initial science campaign involves both spacecraft flying in the same orbit, 200 x 7000 km with an inclination of 60 degrees. This will last approximately 6 months, at which time one of the spacecraft will go into a 60 degree inclination orbit which "crosses" the orbit of the other spacecraft, both still with 200 km perigees. This campaign will operate for approximately 6 months.