The ADRAS-J mission: Methodical Approach to Commercial Space Debris Removal

With the increasing number of launches to meet the demand for satellites, the amount of space debris in orbit is also growing. This has become a concern as it poses risks to functioning satellites and spacecraft. In response to this problem, organizations like Astroscale are focusing on developing commercial on-orbit services for active and defunct satellites, including debris removal.

Astroscale, headquartered in Japan, is one of the companies pioneering in this field. Their recent mission, called Active Debris Removal by Astroscale-Japan (ADRAS-J), aims to demonstrate the necessary operations and technology for debris removal in low-Earth orbit (LEO). The ADRAS-J spacecraft was launched using a Rocket Lab Electron rocket and will survey and approach a large uncommunicative piece of space debris – the upper stage of a discarded Japanese rocket.

Space debris, also known as “space junk,” can take various forms, such as satellites that have reached the end of their operational life or discarded rocket stages. The focus is primarily on LEO, where most of the congestion occurs. Different factors contribute to orbital decay, including altitude, atmospheric drag, and object characteristics. Satellites in LEO usually have a lifespan of five years, while those in geostationary orbit (GEO) can operate for up to 15 years. The Federal Communications Commission (FCC) has introduced regulations requiring satellite operators to deorbit their satellites within five years after mission completion.

The ADRAS-J mission involves approaching the unresponsive upper stage of a rocket and performing various maneuvers to demonstrate the technology required for precise rendezvous and proximity operations with a large target object. The mission uses different navigation techniques and sensors, including smart image processing, infrared, and light detection and ranging (LIDAR), to locate and approach the target object. The spacecraft will capture images every 30 seconds and collect data that will inform Astroscale’s other debris clearance programs.

This mission is part of Japan’s Commercial Removal of Debris Demonstration Project, and it aims to prompt global discussions on active debris removal (ADR) implementation. The Japanese government has issued guidelines on operating spacecraft performing on-orbit servicing, and Astroscale follows these guidelines in its mission. Astroscale has been focused on the safe removal of space debris since its establishment in 2013 and is responsible for the entire lifecycle of the ADRAS-J project.

Astroscale has also developed other missions related to debris management. The ELSA-D mission, in partnership with the European and UK Space Agencies and OneWeb, demonstrated rendezvous operations between two spacecraft. It will be followed by the multi-spacecraft ELSA-M mission, which will demonstrate capture and removal of debris. The COSMIC mission, planned for 2025, will provide deorbiting services for defunct satellites.

Other organizations are also working on debris removal missions. ClearSpace, with the support of the UK Space Agency, is designing a spacecraft called CLEAR to remove defunct objects from LEO. Millennium Space has explored low-cost methods such as wide drag tape to self-deorbit satellites quickly.

The number of satellites launched per year has increased significantly in the last decade, raising concerns about crowded orbits and potential collisions. Satellite constellations like Starlink and Kuiper aim to have thousands of satellites in their networks. In addition to retired satellites and rocket stages, there are around 100 million particles of debris larger than one millimeter in size in space. Scientists are concerned about the possibility of Kessler Syndrome, where collisions could trigger a chain reaction of impacts leading to an untraversable debris field in LEO.

To mitigate risks, space tugs like Northrop Grumman’s Mission Extension Vehicles (MEV) have been developed to extend the lifespan of functioning satellites and reposition them. Future space tugs, like Impulse Space’s Helios tug, could potentially play a role in debris removal.

To wrap it up, organizations like Astroscale are leading the way in developing technologies and services for the commercial removal of space debris. The ADRAS-J mission is an important step towards making space safe and sustainable for current and future generations. With the increasing number of satellites in orbit, it’s important to address the growing issue of space debris and mitigate its risks.