Space debris (the clutter of dead, lost satellites, rocket boosters and other astronautical junk caught up in Earth’s orbit) poses an increasing problem as it circles the globe. Proposed solutions have ranged from a DARPA-developed ‘space mitt‘ to a Swiss ‘space janitor,’ but the Space Debris Elimination initiative put forward by Daniel Gregory of Raytheon BBN Technologies proposes a theoretically simpler option. Gregory hopes that space debris could be forced out of orbit, or massively slowed down, if it were to pass through a giant ‘pulse’ of atmospheric gases fired from the Earth’s surface. Once interrupted by atmospheric gases, the debris would enter Earth’s atmosphere and largely burn up.
SpaDE is currently in development with support from NASA’s Innovative Advanced Concepts program (NAIC) and in partnership with the University of Michigan. The proposed technology does have significant advantages over some other recently proposed methods. Space.com explains “The air pulses themselves would fall back into the atmosphere, leaving no residual trace in orbit to interfere with low Earth orbit satellites,” and SpaDE’s developers claim it to be “fail-safe, in that it places no solid material in orbit where a malfunction could create new debris.”
The less appealing aspect of the proposal is the quantity of fuel required propel the gases into low Earth orbit. Gregory currently estimates that 500 gallons of fuel would be needed, though optimal fuel types and levels are still being determined. He added that while SpaDE presents a more cost-efficient, fail safe method of clearing debris, “Most of the total cost will lie in the cost of energy.”
While the notion of pushing debris towards the Earth might seem unsettling, it’s a fairly standard method in all designs for reducing quantities of space junk. As it stands, satellites and other such junk as well as naturally occurring meteors already largely burn up as they approach the earth. This doesn’t prevent occasional concern over errant chunks of debris which remain intact, and do occasionally crash to earth. Mark Matney, a scientist in the Orbital Debris Program Office explained to MNN last year, the odds of actually being hit by a piece of falling debris stand at around 1 in several trillion.