Brussels, 28 February 2013
Avoiding damage from space debris - space surveillance and tracking proposal
Space debris poses a risk to our space infrastructure and to the space services we rely on in our daily lives and to our safety on earth. Economic losses for European satellite operators stemming from collisions or costly and risky manoeuvres to avoid collisions are currently assessed at around €140 million per year, rising to about €210 million per year within the next decade. The economic loss on the ground due to the disruption of applications or services that rely on data from satellites lost or damaged cannot be quantified, but implies a significantly higher figure.
It is estimated that up to 600,000 objects larger than 1 cm orbit the Earth, and at least 16,000 larger than 10 cm. An object larger than 1 cm hitting a satellite will damage or destroy sub-systems or instruments on board, and a collision with an object larger than 10 cm will destroy the satellite. Space debris also poses a risk to ground-based infrastructures and citizens' security when it falls out of orbit and re-enters the Earth's atmosphere.
Today, the European Commission proposed a new programme to help EU Member States combine their space surveillance capacities and offer services to locate and monitor this dangerous debris and alert satellite operators of collision risks and public administrations of so called uncontrolled re-entries – services known as space surveillance and tracking (SST).
Your mobile phone may be switched off and your flight be cancelled
Without being aware, European citizens rely on space technologies when they use their mobile phones, make financial transactions, take an airplane, watch the weather forecast, or look for the nearest restaurant in their cars. Space-based systems are essential for addressing societal challenges and the implementation of major policy objectives in areas such as environment, climate change, agriculture, transport, development, or security. Any interruption of services which rely on space-based systems can have dramatic economic consequences. The most serious threat to the functioning of satellites and space infrastructures today is the risk of collision with other satellites or space debris.
Space surveillance and tracking can help avoiding risks
Potential actions to mitigate the risks of collision must first focus on gathering information on the exact risks. This will involve monitoring satellites and space debris and cataloguing their positions. When a potential risk of collision has been identified the offending object's trajectory would be tracked so that satellite operators can be alerted to move their satellites. The ability to predict the movement of debris can also help mitigate risks from objects re-entering our atmosphere and falling to Earth. This activity is known as space surveillance and tracking (SST), and is today mostly based on the use of ground-based telescopes and radars.
The Commission proposes to establish a support programme that would help EU Member States to bring together their capacities and offer European SST services. The programme would apply to Member States that own radars and telescopes capable of monitoring satellites and space debris or relevant data centres.
A European SST system will be more efficient
Some EU Member States have national systems, radars or telescopes that could be used for monitoring satellites and space debris, but all in all European satellite operators almost completely depend on United States SST information. However, with increasing space activities, the US will no longer be able to meet the information needs of an increasing number of spacecraft operators. Furthermore, the SST information that the US is ready to share is not sufficient to allow European spacecraft operators to efficiently plan and carry out avoidance manoeuvres.
How will the European SST work?
The European SST services will help securing the launch of satellites, increase the safety of satellite operations by reducing the collision risks, and help to better predict uncontrolled re-entries of inactive satellites or space debris. The services will be available to all civilian (public or commercial) and military satellite operators as well as public authorities concerned with civil security. Member States will retain full control and responsibility over their assets and capacities.
The EU will support this activity by contributing to Member States' costs for setting up and operating the European SST services. Such EU financial support may allow Member States maintain and upgrade their existing capacities or develop new capacities over time. EU funding for the SST support programme will be drawn from other programmes proposed for the EU's next Multi-annual Financial Framework for the period 2014-2020.
What is space debris? How much is there? Where is it?
Space debris is any man made litter left in space and includes parts of rockets to launch satellites, entire inactive satellites or their components, or pieces resulting from past collisions or destructions of satellites. Every time a launch rocket sends a satellite into space, some debris is produced. During the past half century, objects have regularly been launched into space, reaching a peak of 140 items per year during the Cold War.
It is estimated that there are around 16,000 objects orbiting the Earth larger than 10 cm, between 300,000 and 600,000 larger than 1 cm, and more than 300 million objects larger than 1 mm. The population of objects larger than 1 cm is expected to reach around 1 million in 2020.
The vast majority of these objects are not in deep space, but in the orbits used for telecommunications, navigation and Earth Observation satellites.
Space debris is highly destructive
At as speed of 10 km per hour, an object larger than 1 cm hitting a satellite will at least damage or destroy sub-systems or instruments on board, a collision with an object larger than 10 cm will inevitably destroy the satellite. The risk of collision (with space debris between 1 and 10 cm) leading to a complete or partial loss of a satellite is today estimated at 1 every 3 years. The number of collisions with debris smaller than 1 cm is estimated drastically higher at up to 170 collisions per year. This type of collision may just lead to minor failures, which nonetheless can have the effect of shortening the lifetime of a satellite.
Furthermore, inactive satellites and space debris re-enter the Earth's atmosphere in an uncontrolled manner, and can pose a risk to ground-based infrastructures, buildings and human life. According to US research, since the beginning of 1957 more than 22,000 objects re-entered the atmosphere, equivalent to more than one object per day on average. Luckily, as 75 % of the Earth's surface is covered with water, most debris hit the Earth far from inhabited areas.
What can we do to avoid collisions?
Today, the only effective way satellite operators can mitigate collision risks is to move their satellites out of the way as soon as a collision risk has been identified. Each such avoidance manoeuvre costs fuel and shortens the satellite's lifetime. Some European space agencies operating satellites report that on average they carry out 1 collision avoidance manoeuvre every month.
Research activities on technologies and materials to harden satellites against impact of space debris brought about some improvements, but even the most state of art hardening or shielding technologies cannot prevent satellites from being damaged and destroyed from space debris. Other research efforts focus on orbit prediction and the removal of space debris, but work in this domain is at a very early stage. The Commission is currently funding several projects addressing the space debris problem and its removal.
For more information:
Video on space debris: http://ec.europa.eu/enterprise/newsroom/cf/itemdetail.cfm?item_id=6063