RAeS STATEMENT ABOUT SPACE
DEBRIS IN RESPONSE TO
GRAVITY — THE MOVIE
A Specialist Paper by the
Royal Aeronautical Society
www.aerosociety.com
Royal Aeronautical Society - RAeS statement about space debris in response to Gravity — the Movie
RAeS STATEMENT ABOUT SPACE
DEBRIS IN RESPONSE TO
GRAVITY — THE MOVIE
PAT NORRIS FRAeS
RAeS Space Group
Amended and approved by the Chairman and the members of the
RAeS Space Group Committee who were involved in organising the
2 July 2013 Space Traffic Control Conference.
All comments may be addressed to:
Emma Bossom
[email protected]
November 2013
ROYAL AERONAUTICAL SOCIETY
No.4 Hamilton Place
London W1J 7BQ
United Kingdom
T +44 (0)20 7670 4300
E [email protected]
Front cover: The International Space Station during STS-134 from the
space shuttle Endeavour. NASA.
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RAeS statement about space debris in response to Gravity — the Movie - Royal Aeronautical Society
Figure 1. Growth of space debris since 1957. ESA/NASA.
Figure 2. RAF Fylingdales tracks space objects. MoD.
Figure 3. Debris growth scenarios. ESA.
There are currently two regions in space where debris is
becoming an issue: Low Earth Orbit which extends 2,000km
above the Earth’s surface and Geostationary Orbit which is
some 35,786km above the Equator.
Some 20,000 objects larger than a mobile phone are
currently tracked (Figures 1 and 2). But there are estimated
to be over half a million objects bigger than a pound coin
and smaller than a mobile phone and over 50 million objects
smaller than a pound coin — none of which can be tracked
with current technology. These small objects could be lethal
because most are travelling at more than 8km/s at which
speed one gram of debris packs a punch equivalent to 8
grams of TNT.
Even if we launch no new debris the amount will still grow
due to collisions between objects already in orbit. This
phenomenon, known as the Kessler syndrome, is shown in
Figure 3. Therefore we need to reduce the debris population;
one solution that achieves ‘zero growth’ is to remove about
ten large objects from orbit every year.
The situation portrayed in Gravity — the Movie is very
pessimistic. The possibility of a collision such as that shown
in the movie is real, although large objects are usually
tracked with sufficient precision to enable the potential
‘target’ to take evasive action.
Short term actions are being taken to reduce the likelihood
of situation occurring. Operators are protecting operational
spacecraft using avoidance manoeuvres. Many of the world’s
spacecraft operators are members of the Space Data
Association which was specifically set up to reduce the risk
of collisions on orbit. Designers are also reducing the potential for fragments. The UN is promoting Transparency and
Confidence Building Measures to remove suspicion about
motives for tracking and removal of debris. Such measures
could include General Assembly Resolutions, Treaties,
Codes of Conduct and Forums to share information. Lessons
learned from the evolution and deployment of the world’s air
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Figure 4. Possible debris grappling mechanisms include robotic arm (top
NASA) and nets. ESA.
traffic control systems could also be applied to the creation
of a space traffic control environment using transponders on
spacecraft and mandatory reporting of manoeuvres in orbit.
In the longer term, concepts are being developed to remove
rocket bodies and defunct spacecraft using devices such as
harpoons, grappling mechanisms, and nets (Figure 4). We
hope these concepts will lead to demonstration missions
and then to regular operations to remove the most
hazardous objects from orbit. The European Space Agency’s
‘Clean Space’ initiative is an important step in achieving this
goal. UK industry is leading a number of these concepts and
is committed to ensuring that “space remains open for
business.”
All major aspects of the topic were discussed at the 2 July
2013 RAeS conference1 and RAeS publications give
continued coverage of the topic.2
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http://www.aerosociety.com/SpaceTrafficControl
See for example http://media.aerosociety.com/aerospaceinsight/2013/09/27/gravity-film-review/8571/ and further links therein to
earlier RAeS articles and papers on the topic.
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