The risk of a satellite collision above Pittsburgh is high and could result in thousands of pieces of space debris. Two defunct satellites were seen approaching each other on Wednesday at a combined speed of almost 33,000 miles or 53,000 kilometers an hour.
The Infrared Astronomical Satellites (IRAS) space telescope and GGSE-4, a US craft under trial, are traveling in opposing orbits. Space debris tracker LeoLabs reveals that these satellites may pass within 100 meters (yards) of each other at 2339 GMT.
Experts are monitoring the movements, which could take place about 900 kilometers or 560 miles above the city of Pittsburgh in the US.
Evaluating collision risk through radar, LeoLabs points out that the probability of the impact could be between one and five percent. This number is a high risk among the space community.
When satellite crashes happen at very high speeds, also known as hypervelocity, clouds of debris can put spacecraft around the planet in danger.
In an interview with AFP, astrodynamicist Dan Oltrogge says that if the satellites hit, a thousand pieces of debris larger than 10 centimeters, and more than 12,000 fragments bigger than one centimeter could be expected.
Launched in 1983, the IRAS space telescope was a joint project of NASA, Britain and the Netherlands, with a mission that lasted for only 10 months. Based on the data from the European Space Agency, the telescope weighs one tonne (ton) and is the size of a truck, measuring four meters by three meters by two meters.
On the other hand, GGSE-4 was launched by the US Air Force in 1967. This experimental craft weighs 85 kilograms but is only 60 centimeters wide and 18 meters (60 feet) long. Its shape is considered unusual, and it flies vertically.
"We will know because especially for low Earth orbit, there is much radar coverage, and we would see fragmentation happening, we would see objects separating off," Oltrogge said, claiming it would not be visible to the naked eye.
In 2009, the active communication satellite Iridium 33 and the decommissioned Russian satellite Cosmos 2251 collided, there was a debris field of around 1000 large objects in low Earth orbit.
