The MARSCAT Mission will be a multiple 6U CubeSat mission to study the ionosphere of Mars. The mission will investigate the plasma and magnetic structure of the Martian ionosphere, including how the ionosphere responds to solar wind dynamics, what small scale structures exist in the lower ionosphere of Mars, and what processes are responsible for the maintainance of the nighttime ionosphere. The Mars transit proposed is piggy back with a major mission such as Mars 2020, using a CAT burn or a carrier burn for Mars Orbit Injection (MOI). We are proposing to develop the MarsCAT concept further during the Deep Space Small Sat Concept Study opportunity.
This project is primarily intended to make correlated multipoint studies of the ionosphere and magnetic field of Mars. MARSCAT will make in situ observations of the energetic particle flux, plasma density, temperature, and convection in the ionosphere of Mars. They will also make total electron content measurements along the line of sight between the two spacecraft. Following the successful exploration of the Mars ionosphere and its interaction with the solar wind and the crustal magnetic field of the planet, there remain several key questions, which will complete a description of the space environment of Mars. The key questions involve the transport properties of the ionospheric plasma, its role in redistributing the plasma and the role of the magnetic field in modifying the plasma motions. A focus for advancing our current understanding may be obtained by addressing the following key questions.
- How does the ionosphere respond to solar wind dynamics?
- What small-scale structures exist in the lower ionosphere of Mars?
- What processes are responsible for the maintenance of the nighttime ionosphere?
These questions can be addressed with a core capability to measure the major thermal ion composition, the total thermal plasma density, the magnetic field vector, the plasma temperature and velocity, and the energetic particle flux. However, the key to advancing or understanding lies in using multiple platforms to increase the temporal cadence with which a particular volume of the ionosphere can be sampled. With recent advances in small satellite capabilities it is now possible to consider the deployment of a small satellite constellation to accomplish this task. Suitably instrumented satellites could be carried as a secondary payload to a major Mars mission in much the same way as small CubeSat missions have been successfully conducted in low Earth orbit.
In this concept study we will further elucidate how magnetic fields at Mars affect the energetics and dynamics of the plasma at low altitudes and identify the constraints on the measurement capabilities and the operational requirements to successfully conduct the first small satellite constellation to be deployed at Mars.
This mission will be the second or third flight of the Phase Four Radio Frequncy Thruster (RFT) engine, with a first test flight planned for 2017. We will measure the performance of new CubeSat telemetry antennas designed at the University of Houston that are designed to be low profile, rugged, and with a higher gain than conventional monopole (whip) antennas.
The MARSCAT CubeSats will have five instruments: a 3 axis DC magnetometer, a Langmuir probe, a Faraday cup, a solid state energetic particle detector, and a dual-frequency inter-spacecraft total electron content receiver. The MARSCATs will be solar powered. The RFT engine was initially developed by the University of Michigan using a mix of NASA funding and non-NASA private resources, and uses ionized iodine as the propellant for reaction mass. The RFT thruster can provide several km/s of delta-V per kg of reaction mass (depending on payload mass), which is sufficient to reach Mars orbit using major mission piggyback. The MARSCATs will have an active attitude control system, using a sun sensor and flight-proven star tracker for sensing, and CMGs for attitude control. These technologies are already being tested on the NASA-JPL INSPIRE mission.
Questions to be addressed in this proposed study are:
- Review and refine the instrument choices for the CubeSat constellation.
- Evaluate the improvement in science quality with larger number of spacecraft.
- Determine which achievable orbits optimize the science return.
- Optimize the measurement cadence with respect to: instrument capability, telemetry limitations, and science requirements.
- Develop our preliminary strawman concept sketches into actual designs:
- Perform a Risk Analysis for the mission
- RFT propulsion development
- CubeSat versions of science instruments
- UHF Antennas
- Design Spacecraft Subsystem Details
- Perform a Risk Analysis for the mission
- Write a Concept of Operations
- Establish Cost Feasibility