The Need for Situational Awareness: European Space Comes of Age

by Richard Crowther

Europe already has a number of systems in orbit which provide communications and Earth observation as an operational service, but it will be the advent of the Galileo navigation system which signals Europe’s entry into the major league of space-farers along with the United States of America (USA) and the Former Soviet Union (FSU). In the same way that the Ariane launch vehicle guarantees that Europe has independent access to space, the need to ensure the integrity of systems such as Galileo will require that Europe has an independent space situational awareness (SSA) capability.

Space surveillance forms the basis of SSA and is the ability to track and understand what exactly is in orbit from either space or from the ground, and is key to ensuring the free and effective use of space and for monitoring space treaty compliance. As the spatial density of objects in orbit increases, protected regions are being created around the geostationary region, in low Earth orbit, and are being considered in medium Earth orbit. There is increasing pressure to remove objects from these regions at the end of their operational life but limited ability to measure compliance. SSA protects assets (and their associated services) by providing warnings of potential hazards, natural or man-made, unintentional or deliberate, in a timely manner to allow preventative actions to be taken. A particular example is conjunction analysis seeking to determine potential intersection of trajectories between tracked objects, and taking avoidance measures if necessary (and possible).

SSA will be needed to achieve the levels of mission assurance required to deliver and maintain a safety critical service such as that envisaged from the Galileo system as it allows the cause of an anomaly encountered in orbit to be assessed on the basis of informed judgement rather than just surmise. It is important to be able to differentiate between natural phenomena and a hostile action seeking to deny service and thus space weather monitoring is another key element of space situational awareness. The USA recognised the importance of SSA early in the development of its own comprehensive space infrastructure and is manifested in the form of US Space Command with its mission to protect the USA through the control and exploitation of space. The USA is determined to preserve its asymmetric advantage in space to such an extent that the US Air Force is now taking the further step of planning to field defensive and offensive space systems to protect US satellites against enemy assault and to disable those of a potential adversary. Even without Galileo, Europe is becoming increasingly reliant upon space-based resources that provide high-speed data and voice communications, navigation, and weather data. These assets represent many billions of euros worth of public and private investment and play a key role both in national economies, European prosperity, and wealth creation, and such resources need to be protected. These same capabilities underpin growing European military dependence on space and along with intelligence gathering, surveillance, and reconnaissance functions represent a key element of future European cooperation in defence and security. Europe has a choice, it can develop a situational awareness capability either unilaterally or through cooperation which its international partners. Europe’s long standing partnership with the USA in the fields of human spaceflight, solar system exploration, and space and Earth sciences has proven extremely valuable. The recent agreement between Russia and Europe in bringing the Soyuz launcher to the Guyana Space Centre and the commitment of China to the Galileo programme demonstrate other potential axes that could be further developed. Whichever route Europe chooses to follow, it needs to establish its SSA requirements now and to examine the potential options for fulfilling its obligations and ambitions. A system such as Galileo without SSA is not sustainable in the longer term and without a SSA capability, Europe will effectively be flying blind in space.

Links:
Orbital Debris: A growing threat to space operations, Crowther, R., Phil. Trans. R. Soc. Lon. A (2003) 361, 157-168
Space Junk: protecting space for future generations, Crowther, R., Science, Vol. 296, p1241-1242 (2002)