TASTE mission to the Martian moon Deimos

Deimos and Phobos are considered key targets for understanding the origin and evolution of Mars and the outer Solar System planets. To date, there is no clear consensus in the scientific community about the formation of the two moons [1]. There are two main hypotheses for the origin of the moons: they are thought to have been formed by a giant impact between Mars and a protoplanet, or they are captured asteroids. [2].

According to what we know, the surface reflective and spectral parameters of Deimos are roughly like D-type asteroids (carbonaceous chondrites), nevertheless the capture scenario is very problematic dynamically because changing from parabolic to elliptical trajectory needs the loss of kinetic energy due to dissipation, i.e., in the atmosphere of Mars. But Mars’ atmosphere is thin and is not adequate to slow down captured bodies. Besides, the orbits of both moons are strangely placed in equatorial plain of Mars. On the other side, accretion scenarios also meet spectral and compositional difficulties.

To understand the origin and evolution of Phobos and Deimos, in the context of international exploration of the Mars system, it is necessary to have detailed knowledge of both moons. While MMX mission aims to study Phobos, the TASTE - Terrain Analyzer and Sample Tester Explorer mission has the main objective of studying Deimos by combining both close orbit global observations and direct view and analyses of the surface obtained from the lander.

TASTE is a 16U small satellite mission consisting of a 12U orbiter capable of deploying a 4U lander to explore the Deimos surface. The high-level scientific objectives of the mission are to understand the origin of Deimos by combining both global morphology and elemental composition from close orbit and local surface organic and mineralogical composition with a lander, complementing the expected results of the JAXA MMX mission [3].  TASTE orbiter will mount an hyperspectral camera and a miniaturized X-γ-ray spectrometer to characterise the elemental composition of the surface, while the Lander will mount a RGB camera and the Surface Sample Analyser (SSA) a lab-on-chip device to analize the chemical composition of the moon. Furthermore, the radio mounted on the orbiter will be used to acquire data on the gravity field of Deimos. All the cited instruments will work alone and in synergy to achieve the scientific objectives.

Once the spacecraft arrives at Deimos after completing the transfer, it needs to start orbiting the Martian satellite from a close scientific orbit. Due to the strong gravity pull of Mars and the mass of Deimos being too small to capture a satellite, it is not possible to orbit the Martian moonlet in the usual two-body sense. However, Quasi-Satellite Orbits (QSO) can be sufficiently stable to allow operations in the vicinity of Deimos. Two target QSO are identified- A large QSO with a distance oscillating from 31 km to 50 km from the centre of mass of Deimos, called Mapping-1 orbit, serving as a stationing orbit for the “far-range” phase and a small QSO called Mapping-2 orbit, with a radius of 16-18 km, for the higher resolution imaging of the surface, and for releasing the lander to a falling trajectory on the surface of Deimos, as foreseen for the “close-range” phase.

TASTE has started Phase B and it is funded by the Italian Space Agency under the ALCOR programme. TASTE represents an innovation in the CubeSat landscape, combining the development of space technology with cutting-edge scientific analysis for scientific investigations in low-gravity environments in deep space. This talk will present the scientific objectives and mission design.

 

Acknowledgements: TASTE is supported by the Italian Space Agency (ASI) within the ALCOR Programme (Contract TASTE n. 2024-45-I.0). The project is lead by the Italian consortium INAF-Arcetri Astrophysics Observatory, Firenze, Astronomical Observatory of Trieste and the Politecnico of Milano-DAER, Milano, Italy.

 

References: [1] Rosenblatt et al., (2016), Nat. Geosci, 9, pp.581–583. [2] Murchie et al., (1999), JGR, 104 (E4), pp.9069-907.  [3] Campagnola et al., (2018), Acta Astronautica, 146, pp. 409-417. [4] Tra-Mi Ho et al., (2017), Space Science Reviews, 208 (1-4). [5] Wallace et. al., (2012), Astrodynamics Specialist Conference, p. 5067.