ESA / Enabling & Support / Preparing for the Future / Discovery and Preparation 12/12/2023
ESA is venturing towards putting a spacecraft into orbit around Mars using a technique that engineers have studied for over half a century but never dared to attempt.When Mars Express arrived at the Red Planet on Christmas Day 2003, it was travelling at 18 000 km/h. It had to fire its main engine to slow down enough to be captured into orbit and avoid flying off into space. The braking was a success, but it used 264 kg of propellant.This technique has been used successfully at Mars for 16 missions since 1971, including ESA's Trace Gas Orbiter in 2016. But for future missions, there could be another way. Mars is surrounded by an atmosphere: what if we flew a spacecraft straight through it, making use of atmospheric drag rather than propellant to slow it down?
This idea, known as 'aerocapture', is not a new one. It has been tempting engineers since the mid-1960s for two main reasons. Firstly, it would reduce the amount of propellant that the spacecraft needs to carry. Secondly, it would mean that we could choose to arrive at a planet with a higher speed, cutting cruise time.
Aerocapture could enable small spacecraft to reach orbit, and in future be useful also for larger spacecraft in human exploration scenarios. While Mars is an attractive first destination for the application of aerocapture beyond Earth, the technique’s advantages are particularly apparent for ambitious scientific missions to worlds with atmospheres beyond Jupiter.
But aerocapture has never been attempted, neither at Mars nor at other worlds. The idea has so far been perceived as too risky for its first use in a scientific mission, and sending a spacecraft to Mars with the sole aim of demonstrating aerocapture had been thought too expensive.
More:
https://www.esa.int/Enabling_Support/Preparing_for_the_Future/Discovery_and_Preparation/ESA_explores_bold_new_approach_to_Mars_orbit
