Abstract
This paper describes two novel methods used to reduce the prefiring injector temperatures of thrusters on the sun-facing side of a spacecraft designed for a mission to Mercury. The Mercury Transfer Module is the propulsion module that takes the European Space Agency’s BepiColombo mission to the planet Mercury. It contains a bipropellant chemical propulsion system and a xenon-based electric propulsion system. It was predicted that, within a certain distance from the sun, the high solar loads and large internal waste heat from the electric propulsion would cause vapor lock to occur on the sun-facing hydrazine thrusters at the start of firing, rendering their performance unpredictable and inefficient. The paper reports on the development of a method to increase the emissivity of the nozzles via sandblasting and on the development of a special copper collar for directly removing heat from the injector. The design and analysis are reported, along with results from a dedicated thruster-level high solar flux thermal test and a full spacecraft-level thermal test using a flight-representative thruster to which the modifications as described in this paper. The two techniques are shown to enable unrestricted use of the thrusters all the way to Mercury.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have