Done wrong, forcing an unmanned aerial vehicle or drone to the ground can be like removing a thorn bush with a spiked baseball bat — sure, you’ll get the job done, but no one is giving you points for safety. If you’re worried about a drone that might crash into, say, someone’s head, your countermeasure should neither explode the drone nor force it into an impersonation of an anvil.

That’s the motivation behind a challenge the non-profit MITRE Corporation is offering: a hundred grand to the researcher, engineer, or individual developer who can track, detect, and ground a small UAV, without harming the machine or anything it’s carrying.

It’s a two-step process, as the White House outlined when it announced the prize in October. First, submit a paper showing how the system will work. Then MITRE will test small drones in a “controlled model urban environment.” Best in show gets $60,000, best detection gets $20,000, best interdictor gets $20,000, but if there’s a clear overall winner, she or he takes all.

Thanks to the no-damage stipulation, that means no lasers, guns, rockets, or missiles, as Michael Balazs, a MITRE systems engineer, told Fortune this week.

What might such a system look like? A few drone countermeasures have bubbled up, with varying levels of practicality. Take, for instance, the Rapere, a theoretical quadcopter countermeasure that consists of another quadcopter dropping a rope that tangles in the bogey’s props. The downside of this is you have to develop a precise algorithm to position the Rapere above the target drone. It also does nothing to address that pesky crashing problem.

For the ground-bound there are proposed “radio-jamming guns,” such as a device unveiled by the technology company Battelle in October. Down this avenue, however, sit big ol’ legal speed bumps in the form of the Federal Communications Commission. (Battelle may have already hit a few of them; the announcement video is now listed as private on YouTube and the original link to the October 13 press release is dead.)

If you’ve got a way to wrangle a sub-5-pound drone out of the sky, you’ve got till February 7 to submit it.

Photos via Getty Images