Probing satellites' mysterious death tumbling

May 29, 2014
Probing satellites’ mysterious death tumbling
More than half a century of launching into orbit has left Earth surrounded by a shroud of debris, formed of disused satellites and smaller fragments. Credit: ESA

Down on the ground, death equals stillness – but not in space. Derelict satellites can tumble in unpredictable ways and ESA's team tasked with developing a space salvage mission want to find out why.

In recent years, satellites beginning uncontrolled reentries have been tracked, such as Russia's Phobos-Grunt and Germany's Rosat. In a few cases, satellites suffering unexpected failures in orbit have also been followed, including ESA's Envisat and Japan's ADEOS-II.

In every case, the satellite has been seen to be tumbling – but the reason why remains a mystery.

Similarly, when control of a satellite is temporarily lost, ESA's Operations Centre team in Darmstadt, Germany, are accustomed to fixing the satellite's attitude as a prelude to recovery – helping to better understand the satellite's status.

ESA's Clean Space initiative – tasked with reducing the 's environmental impact on Earth and space – is seeking to transform our understanding of how large, dead objects behave in space, encompassing launcher upper stages as well as satellites.

The aim of a new study is to combine detailed computer analysis with a range of ground-based observations, some which have only rarely been tried.

On 15 April, the French space agency CNES rotated the Pleiades Earth observation satellite to capture this image of Envisat. At a distance of about 100 km, Envisat’s main body, solar panel and radar antenna were visible. Credit: CNES

Optical telescopes and ground radar are today's favoured monitoring methods, but the study will also investigate the potential of optical and radar satellites in nearby orbits for space-to- observations.

Highly accurate laser ranging will also be attempted. A global network of ground stations would bounce lasers off a satellite's retroreflectors – like 'cat's eyes' built into a motorway.

Laser ranging can pin down a satellite's position to within centimetres, but has seldom been attempted on out-of-control objects.

The hope is that sustained observation of particular objects over time will give new insights into the kind of factors influencing attitude changes, and how this motion is likely to change over time.

Meanwhile, specialised simulations will seek to pin down these drivers and develop reliable forecasts of how derelict satellites behave.

Phobos-Grunt image taken from ground, 29 November, by amateur astronomer Ralf Vandebergh, in The Netherlands. Credit: ESA/Ralf Vandebergh

The long list of potential perturbations include changes in the satellite's centre of gravity as parts break off, atmospheric drag, the faint but steady push of sunlight, micrometeoroid and debris impacts, internal magnetic fields, outgassing and fuel leaks, exploding batteries and even the sloshing of leftover fuel.

For Clean Space, this study is of more than academic interest. The team is planning a dedicated salvage mission called e.DeOrbit and improving our knowledge of a target's condition will help to fine-tune the design.

Bidders are welcome on the study contract. For more information, check the invitation package, accessible here.

Explore further: Capturing derelict satellites adrift in orbit

add to favorites email to friend print save as pdf

Related Stories

Capturing derelict satellites adrift in orbit

Feb 24, 2014

Standard space dockings are difficult enough, but a future ESA mission plans to capture derelict satellites adrift in orbit. Part of an effort to control space debris, the shopping list of new technologies ...

Taking weather forecasting into the future

May 21, 2014

The first documents signalling the go-ahead for Europe's fleet of MetOp Second Generation weather satellites were signed today in the presence of the German Chancellor Angela Merkel at the Berlin Air Show.

Reducing debris threat from satellite batteries

Mar 14, 2014

(Phys.org) —Across a satellite's working life, batteries keep the craft's heart beating whenever it leaves sunlight. But after its mission ends, those same batteries may threaten catastrophe.

Recommended for you

NASA issues 'remastered' view of Jupiter's moon Europa

Nov 21, 2014

(Phys.org) —Scientists have produced a new version of what is perhaps NASA's best view of Jupiter's ice-covered moon, Europa. The mosaic of color images was obtained in the late 1990s by NASA's Galileo ...

European space plane set for February launch

Nov 21, 2014

Europe's first-ever "space plane" will be launched on February 11 next year, rocket firm Arianespace said Friday after a three-month delay to fine-tune the mission flight plan.

Space station rarity: Two women on long-term crew

Nov 21, 2014

For the 21st-century spacewoman, gender is a subject often best ignored. After years of training for their first space mission, the last thing Samantha Cristoforetti and Elana Serova want to dwell on is the ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.