In April 2012, the European Space Authority lost contact with its Earth observation satellite Envisat, rendering it inoperative. Envisat will orbit Earth for approximately another 150 years before burning up upon re-entry into the atmosphere. If the enormous 8-ton ghost satellite were to collide with another object and break apart, the resulting debris cloud would escalate the already serious threat to operating satellites.
A new report by Allianz Global Corporate & Specialty (AGCS), titled Space Risks: A new generation of challenges, explores the considerable risks millions of orbiting fragments pose for satellites and space missions and stresses the need to actively remove debris is now urgent. The report also highlights the insurance industry’s pivotal role in enabling the space industry.
“The space around our planet is becoming increasingly congested,” says Thierry Colliot, Managing Director of Space Insurance at AGCS. Since space exploration began in 1957, objects have been left there by humans, ranging from used rocket boosters and defunct satellites to space exploration equipment that has gone lost or exploded. “Today, the space debris situation has become irreversible,” says Colliot. “The number of objects is now so high that it won’t decay on its own through atmospheric drag. Instead, it’s actually increasing as objects collide and produce fragments, which in turn collide in a runaway chain reaction.”
More than 35 million objects in orbit
Close to 800 satellites orbiting the earth’s atmosphere currently provide geographical data, weather information or telecommunication services. These are under permanent fire by space debris. An estimated 16,000 objects larger than 10 cm have been cataloged so far. However, the projected amount of uncataloged objects dwarves this number. Estimates place the figure of small objects between 1 and 10 cm at around 300,000, and at 35 million for objects smaller than 1 cm. These objects travel at very high velocities of 10 km per second, which is more than 10 times faster than a bullet. At these speeds, even tiny fragments can have a devastating impact. They can penetrate the surface of satellites and can severely damage the electronics, causing total loss in a worst-case scenario.
How can satellites be better protected? To avoid collisions or mitigate collision effects, avoidance maneuvers can be initiated, though trajectories of larger objects cannot always be predicted reliably or early enough. Further, multi-layer insulation shields or impact absorption systems can limit damage in minor collisions.
Deorbiting not good enough
Besides protecting satellites, space authorities and scientists work hard to reduce overall space debris congestion. Today, satellite operators are obligated to deorbit satellites within 25 years of their mission’s end, though only the latest generation of satellites have such functionality. One of the deorbiting techniques is achieved through a destructive re-entry into earth’s atmosphere. Most of the structure burns up, owing to the drag and intense heat it generates. The remaining unburned fragments fall into uninhabited parts of the world or into the sea.
“Systematic deorbiting of new satellites at the end of their lives won’t suffice, however,” notes Colliot. According to experts, an additional 10 major objects would need to be eliminated each year to reduce the debris population to a stable and sustainable level.
New technologies to eliminate or remove debris encourage hope. For example, laser tools that destruct larger objects or space tethers could enable a controlled deorbiting of entire systems. “There are exciting concepts of active debris removal,” acknowledges Colliot. “However, at this stage, because of the high cost involved and technological restraints, we have not yet seen a real breakthrough.”
Most commercial satellites are insured
To fulfill their missions economically, about a quarter of all satellites in the Earth’s
orbit are insured against losses from physical damage, as well as service interruption. Most insured satellites belong to commercial telecom providers. These satellites operate in so-called Geostationary Orbits at an altitude of 36,000 km above the Earth’s equator for up to 15 years and have a value up to $200 million each at their launch phase. Most other satellites are used for Earth observation and are operated by governments on a ‘self-insured’ basis. Their value is about $40 million each and they usually operate for up to five years in Low Earth Orbits at altitudes of between 300 km and 2,000 km.