Satellites are heavy pieces of infrastructure, entails huge amount of budget, human resources and time. But, when they run out of fuel or any breakdown comes about in any part of it, the satellite is abandoned. This in return brings in heavy loss and also creates lots of space wreckage. Thanks to on-orbit satellite servicing, this is now on the verge of being a story of past.
As the name suggests, on-orbit satellite servicing is the technology that repairs, refurbish and refuel satellite which has already been launched. The technology is an exciting new area and a great technological transformation in the space sector. The capability is the gateway to an entirely new infrastructure for Earth observation, communications, space exploration, space travel, and habitats, and integral part to build a better world.
How On-orbit satellite surviving is done
The process of on-orbit satellite is very simple. For the purpose, a service spacecraft is built with robotic arms. The major components here includes an advanced spacecraft with a specialized toolkit and robotic arms just like humans for capturing, interacting with, and manipulating a client, software for managing semi-autonomous servicing tasks, and an advanced sensor suite for careful rendezvous and proximity operations. In case when any satellite developing a snag is discovered, the servicing spacecraft is made to approach it, grab it, pull it close, and repair or exchange the faulty part with a toolkit it is carrying. If a satellite runs out of the fuel, similar technology is used to refuel it.
The actual servicing process changes depending on the design, orbit, and needs of the client spacecraft, but generally includes rendezvous and gentle capture of the client, completion of servicing tasks using the servicer’s robotic arms and toolkit, and then release of the client within a few days.
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In past, it was not possible to repair all satellites in orbit. It was mandatory to build them accordingly so that they can be serviced. Like for example when all three rubidium clock of IRNSS 1A satellite failed, then it was pushed to graveyard. The satellite was launched by Indian space and research organization (ISRO) as the first in the queue of India’s own regional navigation system, NAVIC. But today the technology has matured and can repair all satellites on orbit. The Servicer designed SSL is compatible with most government and commercial spacecraft that are currently in orbit, even those not designed to be serviced in space.
Challenges of On-orbit satellite servicing
As every technology comes with a challenge here the key challenge lies in integrating the communication system as distance increases between the satellite repair system and ground station. In such case, it becomes tough to locate and then rendezvous dock spacecraft that has to be serviced. The path to this goal requires a strong system engineering approach to combine the available technologies, tools, and procedures to overcome which brings together some economic challenge. Maintenance or upgrade without any technical glitch means launching a new satellite to replace something that may have a fully functional set of subsystems which increases their cost. The real economic challenge lies in determining the value of servicing like comparing the cost of a servicing mission to the cost of replacing the failed satellite as well as the potential returns from the serviced satellite.
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Overall Benefits
On-orbit satellite servicing will elongate the life of some very expensive satellites. Its application areas are very broad where each one has its own importance based on scientific, economic, strategic, and societal benefits. Repair and maintenance of the satellites in space keep a unique and valuable asset operational, essentially improving it beyond its design lifetime or the reliability of its subsystems. It improves overall mission robustness and offers a unique capability to improve risk posture through post-launch operations.
