Aerobraking: Review of the state of the art and required developments

Aerobraking is the process of circularising an eccentric spacecraft orbit using aerodynamic drag in a planetary atmosphere, most commonly for interplanetary mission applications. Since its first in-space demonstration in 1991, aerobraking has been successfully performed in a total of eight missions, at Earth, Venus, and Mars. Despite this promising track record, aerobraking has arguably not yet reached its full potential. For instance, the most recent mission with aerobraking was launched around a decade ago, and the technique has only been used by relatively large spacecraft weighing over 100 kg. Against this backdrop, this article performs a comprehensive review of the state of the art in preparation for the next generation of missions with aerobraking. First, the eight missions that have already performed aerobraking are summarised. Important data on the aerobraking performance is extracted. Second, opportunities opened by aerobraking for interplanetary transportation and science are evaluated. Significant propellant savings can be achieved compared to a conventional propulsive manoeuvre, reducing launch mass and cost. Aerobraking also offers insights into atmospheric science and rarefied gas dynamics. Third, however, important challenges remain to make aerobraking easier. Resource-intensive ground-based operations and atmospheric uncertainty are two notable ones. These are examined in detail and potential ways forward are reviewed, including autonomous aerobraking. Fourth, a future outlook is provided, including on potential synergies between aerobraking, small satellites, and space sails. It is hoped this paper will help to inject new wind into aerobraking research and applications.