The Earth is currently surrounded by debris launched into space over several decades. This space junk can collide with satellites and not only cause damage to spacecraft but also result in further debris being created.
To preserve a secure space environment, the active removal or de-orbiting of space debris is an emergent technological challenge. If remedial action is not taken in the near future it will be difficult to sustain human space activities.
To overcome this issue, several methods for the removal and de-orbiting of debris have been proposed so far; classified as either contact (e.g., robotic arm, tether net, electrodynamics tether) or contact-less methods (e.g., laser, ion beam shepherd), with the contact-less methods proving to be more secure.
The ion beam, in the contact-less method, uses a plasma beam ejected from a satellite to impart a force to the debris slowing it down which results in it falling to a lower altitude. The debris then enters the Earth’s atmosphere where it burns up naturally.. However, ejecting the plasma beam toward the debris dramatically speeds up the satellite in the opposite direction making it difficult to maintain a consistent distance between the debris and the satellite.
To safely and effectively remove debris, two propulsion systems have to be mounted on the satellite to eject bi-directional plasma beams (Figure 1). This interferes with a satellite system integration requiring the reduction of a satellite’s weight and size.
“If the debris removal can be performed by a single high-power propulsion system, it will be of significant use for future space activity,” said Associate Professor Kazunori Takahashi from Tohoku University in Japan, who is leading research on new technology to remove space debris in collaboration with colleagues at the Australian National University.