Tsubame (SLATS)

Launch data: Designation  43066 / 17082B Launch date  23 Dec 2017 - 01:26 UT Launch site  Tanegashima, YLP-1 Launch vehicle  H2A-202 Mission  Technology Earth orbit: Perigee / Apogee  470 x 655 km Eccentricity   Inclination  98.7° Period   min

Description:

• SLATS (Super Low Altitude Test Satellite) is an engineering test satellite currently under development in JAXA in an attempt to develop techniques to operate an satellite in extremely low earth orbits. In the presence of aerodynamic forces acting on the satellite, the altitude and attitude of the satellite are maintained by ion engines so that the aerodynamic drag can be cancelled.
• For a super low altitude satellite, only low-thust thrusters are needed, although atmospheric resistance increases. A long-life and high-fuel efficiency thruster is required. An ion engine is the most appropriate type of space engine, when considering these conditions. From the perspective of exerting the greatest possible thrust, the propellant used in the SLATS ion engine is Xenon gas, which is the same propellant that was used in Hayabusa. Furthermore, SLATS uses technology developed for ETS 8, which realizes greater thrust than Hayabusa.
• The atmosphere becomes denser closer to the surface of the Earth, and the concentration of atomic oxygen increases at super low orbital altitudes. Atomic oxygen is known to damage the golden thermal control films (Multi-Layer Insulation) that are used for satellites. Atomic oxygen is highly reactive and causes damage material used on the surface of satellites. For SLATS, countermeasures have been taken such as applying a coating which is highly resistant to atomic oxygen to the outer surface of the multi-layer insulation. SLATS is also equipped with an atomic oxygen monitoring system which measures the concentration of atomic oxygen and the deterioration of materials when reacting with atomic oxygen. The acquired data will be used in the design of future super low altitude satellites.
• The satellite will be renamed Tsubame – meaning Swallow – after deployment.

Mission details:

• The Tsubame low orbit satellite launched on Dec, 2017 23 has begun testing its propulsion system. Its apogee was lowered by 20 km in 2 burns on Jan 13 and 15, 2018 leaving it in a 456 x 608 km orbit. Initial low operational orbit is expected to be 268 x 268 km.
• The Tsubame (SLATS) low orbit test satellite reentered on Oct 1, 2019. Its final orbit was 133 x 147 km.

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