Catching orbital debris will not be easy.
Once a spacecraft travels into orbit, it must detect and approach its target, which may be tumbling uncontrollably, grab onto it and drag it out of orbit without destroying or losing control of either spacecraft, said Marlon Sorge, senior project engineer for The Aerospace Corporation’s Space Innovation Directorate.
Luisa Innocenti, who heads ESA’s Clean Space Office, agrees active debris removal will be technically challenging, but she’s confident it can and will be done. After all, “ESA landed on a comet,” she said. “If we could do that, we can capture the object.”
Then, there are the legal hurdles. Under the 1967 Outer Space Treaty, any spacecraft launched by a nation remains its property even decades after it stopped working.
“A U.S. company can’t go up and grab random debris,” said Theresa Hitchens, senior research associate at the University of Maryland’s Center for International and Security Studies. “If it’s Russian debris, a company has to have Russian permission to get it. And if it’s old debris in small pieces, how do you really know whose debris it is?”
Even if a company obtains government permission to collect a defunct satellite or spent rocket stage in orbit, the project raises legal questions. For example, what if the debris strikes another satellite in orbit or breaks up on reentry and damages property on the ground in a country that wasn’t involved in the mission? The liability issues need to be sorted out, Sorge said.
Until they are, countries will send debris-retrieval satellites to capture their own spacecraft. Switzerland’s CleanSpace One is going after SwissCube. ESA’s e.Deorbit mission was designed around Envisat, the agency’s own Earth-observation spacecraft. And commercial missions are bringing along their own small satellite targets.
Once those missions show active debris removal is possible, active debris removal ventures will face their biggest challenge: raising money for the ventures.
Nobody has a clear idea how much active debris removal should cost, said Luc Piguet, École Polytechnique Fédérale de Lausanne scientific adviser.
A series of commercial missions in the next few years will shed light on the cost of debris removal and reveal government and commercial demand for the service.
“In today’s world, it is not enough to say, ‘I will do something because it advances technology and cleans something up,’” Innocenti said. “You also have to demonstrate a business link.”
ESA member states agreed that e.Deorbit, the agency’s initiative to capture the defunct Envisat, was “a fantastic mission” and they would like to fund it, Innocenti said. “The problem comes when you have to prioritize with respect to a launcher, Earth observation, telecommunications support, science and all the rest. It’s a question of priority. If it had the commercial return, that would change the priority.”