67 years after the launch of the first machine into space, the Soviet satellite Sputnik In 1957, more than 131 million space debris between 1 millimeter and 10 centimeters orbit the Earth, according to data from the European Space Agency. If we go to larger objects, larger than a softball that has a circumference of 30 centimeters, there are more than 30,000 the elements that today are space junk in Earth’s orbit. And among all of them, About 2,000 are really big and correspond to rockets used in launchesmost of them intact, continue to orbit the Earth. But until now, no one had launched a satellite to check what one of these used rockets looked like after many years orbiting the planet. It was the first step towards developing a system that would allow them to be safely deorbited.
Last February, the Japanese company Astroscale sent a small satellite into low Earth orbit on a launcher Rocket Lab. A couple of months later, the ship ADRAS-J from Astroscale, Active Debris Removal by Astroscale-Japan or Active Debris Removal by Astroscale-Japan, reached the position of a Japanese rocket that has been in orbit for more than 15 years.
These spent rocket stages are considered The most dangerous type of space debris because of its size and because it sometimes retains fuel and electrical energy that can cause explosions long after their missions are over.
ADRAS-J photographed the upper stage of the H-IIA rocket from a distance of several hundred meters and then moved away. This was the first publicly released image of space debris captured from another spacecraft using rendezvous and proximity operations, RPO for its acronym in English.
Since then, Astroscale has performed more complex maneuvers around H-IIA, which has been orbiting Earth since deploying a Japanese climate research satellite in January 2009. Astroscale attempted to complete a 360-degree flight around the H-IIA rocket last month, but the ship, after detecting an anomaly, autonomously canceled the maneuver.
ADRAS-J was away from the H-IIA rocket for several weeks. Once engineers determined the cause of the failure that triggered the abort, ADRAS-J fired its thrusters to approach the upper stage again this month. Astroscale’s spacecraft is about the size of a kitchen oven, while The H-IIA rocket you’re visiting is almost as big as a city bus.
The satelite completed two flight maneuvers around the H-IIA upper stage on July 15 and 16, examining all sides of the rocket while more than 560 kilometers of altitude. Engineers also wanted to measure the upper stage’s spin rate and spin axis. Despite exposure to the harsh conditions of space, the foam insulation encasing the rocket is holding up and the engine nozzle still shines as if 15 years had not passed.
ADRAS-J autonomously maneuvered around the rocket at a distance of about 50 metersusing navigation data from a light detection and ranging sensor and Astroscale’s custom guidance algorithms to control its position, as the vehicles moved around the Earth at 7.6 kilometers per secondThis is the most difficult challenge for ADRAS-J, as the rocket is underpowered and unable to maintain position. The upper stage also lacks laser reflectors and homing points that would help an approaching spacecraft.
These types of RPO maneuvers are not uncommon on manned and cargo ships traveling to the International Space Station and they carry them out around it, but it is the first time that they have been carried out with space junk. ADRAS-J is the first phase to reach have a system that allows you to get rid of these types of objects which pose a risk to satellites and space stations in orbit.
In collaboration with JAXAthe Japanese Space Agency, Astroscale is developing a follow-up mission called ADRAS-J2 to dock with the same H-IIA rocket visited by the current mission and direct it towards a trajectory that allows it to re-enter the atmosphereAstroscale hopes that a successful demonstration of this capability on the ADRAS-J2 mission will lead to additional contracts from commercial or government operators to remove large pieces of space debris from orbit.
After completing the final flight maneuvers around the rocket, Astroscale will attempt to move ADRAS-J even closer, as much as a couple of metersto demonstrate more of the capabilities needed for ADRAS-J2.