Three shuttle astronauts wrestle INTELSAT VI onto its new apogee motor
We can do this one small thing today
Despite decades of study, and warnings about the growing threat of space debris, we still build rockets and satellites with little regard for their recovery and disposal. We knew, but did not act. Now, the challenge of removing space debris from orbit has been made immensely more difficult and costly by our failure to act.
Satellites are designed to achieve orbit and operate until they are nearly out of fuel. They are then removed from their operating orbit and passivated. This is where we abandon them and they apparently become someone else’s concern.
Because satellites have not been designed for recovery, significant work is now required to develop ways to intercept these objects and remove them from orbit. Creative ideas for ADR include harpooning, throwing nets, and attaching tethers. This is work that would not be needed had we designed these objects to be recovered in the first place! Unfortunately, we continue to build and launch satellites without a thought to their recovery and disposal. This practice must end.
Years ago, NASA developed a concept they called Design to Demise
The premise being that anything launched into space that could re-enter earth’s atmosphere (particularly an uncontrolled return) should be built using materials with sufficiently low melting points to burn up on re-entry. The goal is to protect us from returning debris. We need to extend this concept by designing satellites for rendezvous and capture and complete the cycle to their ultimate demise.
In this regard, the current debris mitigation practice is incomplete, in that it relies upon positive control of a satellite at its end of life for removal and passivation. It doesn’t address recovery operations following the failure of a satellite on orbit, nor any future Active Debris Removal (ADR) missions.
Failed satellites are particularly problematic
Not only do they remain in an operating orbit, threatening operating satellites sharing that orbit, but they are also a greater debris threat due to potential explosions from propellants and batteries. For this reason, failed satellites are especially good candidates for early ADR missions. Ultimately, however, we will need to remove satellites from their graveyard orbits and dispose of them.
We must start building satellites with devices and mechanisms that make them more cooperative for rendezvous and capture operations. Possible solutions could be as simple as a rigid boom with a ball at the end for capture, and radar reflectors or optical badging to aid attitude determination and alignment for a final secure connection. More advanced configurations could permit external passivation by an ADR vehicle, or retraction of solar arrays and deployed antennas; reducing the conjunction cross-section.
Designing satellites for recovery today will significantly lower future ADR costs and risks
Given the threat debris poses to future space operations, it is wholly irresponsible to continue launching objects into near earth orbit absent consideration for their recovery. Future ADR mission planners will certainly thank us for having the foresight to include such features in our designs going forward.