Limits of drag augmentation at spacecraft end-of-mission and a mitigation strategy

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Limits of drag augmentation a mitigation strategy

https://doi.org/10.1007/s42064-020-0092-7

at

spacecraft

end-of-mission

and

Emma Kerr, Malcolm Macdonald () University of Strathclyde, Glasgow G1 1XJ, UK

ABSTRACT

KEYWORDS

An increasing number of objects are being launched into low-Earth orbit. Consequently,

drag augmentation

to avoid the possibility of future in-orbit collisions space object removal techniques are

volume

receiving attention. As one of the most developed techniques, drag augmentation is

area-time-product

increasingly being considered as an option for end-of-mission removal of objects from low-

space debris

Earth orbit. This paper highlights a common misconception around drag augmentation:

liability

although it can be used to reduce de-orbit time, when used inappropriately it can increase

Learned Hand formula

the volume swept by an object and, thus, increase the occurrence risk of collision with

calculus of negligence

another space object. Knowingly ignoring this increased risk of collisions could leave spacecraft operators, and consequently their responsible state party, open to liability

Research Article

risk. By investigating the volume swept and de-orbit lifetime, a strategy of delayed

Received: 6 April 2020

deployment is proposed as a compromise between reducing volume swept and time to

Accepted: 11 August 2020

de-orbit. However, this increases system complexity and, likely, cost.

© The Author(s) 2020

1

Introduction

In January 2007, China conducted a direct-ascent antisatellite test, destroying the 750 kg Chinese weather satellite FY-1C (COSPAR identification 1999-025A) at an altitude of 865 km using a kinetic kill vehicle traveling in the opposite direction [1]. Whilst not the first, nor most recent such test in space, the altitude was higher than prior Russian and US tests, and a more recent Indian test, creating a prolonged and dispersed debris cloud that has had a significant impact on the space debris environment in low-Earth orbit (LEO). In February 2009, the defunct Cosmos-2251 (COSPAR identification 1993-036A) and active Iridium-33 (COSPAR identification 1997-051C) satellites collided at an altitude of 789 km [2], the first observed hypervelocity collision between two artificial satellites, leading to further growth in the LEO debris population. These two events have significantly increased awareness of the challenge presented by space sustainability. Meanwhile, the number of spacecraft launched per year has recently and rapidly increased. This trend is a result of the increased use of standardized, small and micro-satellite, platforms such as the CubeSat [3, 4]. As  [email protected]

such, the prudency of space debris mitigation standards and regulations means space actors are increasingly implementing end-of-mission disposal plans to be, and be seen as, responsible and sustainable actors. No international treaty exists to specifically deal with the issue of space debris. However, both the Outer Space Treaty and the Liability Convention address