It’s been a little while since I checked in with the goings-on back at my Cornell research lab. Totally unsurprisingly, some very cool things are happening there!
One is that the Sprite and KickSat project has gone all the way from a back-of-the-envelope concept when I was at the lab to a flight manifest! Sprites are tiny spacecraft – think the size of a coin – that consist of little more than a solar cell, a little CPU, and a diminutive radio. They are pathfinders for an idea that, rather than relying on a single monolithic (and super-expensive) spacecraft, instead we could just run off a batch of a million tiny satellites and fling them all out into space to cooperatively complete a mission. Some of the applications we talked about included integrating basic lab-on-chip functionality to test for biomarkers, and then rain a bunch of the Sprites down onto Mars or Europa. They wouldn’t return the same wealth of data of a NASA flagship mission, but they would tell us where the interesting things are. Another reason why tiny spacecraft are cool is because they interact differently with Solar System objects than large vehicles do – so they might be able to take advantage of light, magnetism, or planetary atmospheres in different ways.
The KickSat project was the brainchild of grad student Zac Manchester. It’s a simple CubeSat design with a spring-loaded deployer, designed to release a couple hundred Sprites. On the ground, Zac can then track the intermittent radio signals from all these mini-spacecraft, and evaluate how well their unshielded components survive in space. Radiation will eventually kill them, but with many copies of the same spacecraft, we’d expect to see them die out statistically. They’re spacecraft with a half-life, and as long as the half-life is long enough to complete the mission, we don’t care that a huge number of Sprites burned out.
When I left the lab, Zac was applying for grants to build the KickSat hardware. But – despite the cool concept – there weren’t any takers. Eventually, he decided to turn to KickStarter to see if he could crowd-fund some spacecraft research. He ended up raising almost three and a half times as much money as he asked for, and become something of a pioneer for crowdfunded space activities! Zac is now working at Ames Research Center to perfect the Sprite and KickSat designs. They will be launching on the same SpaceX Falcon 9 rocket that will carry supplies to the International Space Station in September. This is actually the first CubeSat from my lab to make it all the way to launch, so I say: Go Zac!
Second, a project that is perhaps a little less flashy but a little closer to my heart has been making some great strides. Ben Reinhardt has been squirreled away in the same basement lab I remember, working on what he calls “eddy-current actuators.” The more fanciful – and very nearly accurate – name for the devices he is working on would be “tractor beams.” He wants to use these to grab onto defunct satellites, the outside of the Space Station, or maybe even some asteroids and comets, all without mechanical contact.
I was still active in the lab when this project got off the ground. In fact, I put together one of our first tabletop demonstrations of the principles involved: a changing magnetic field generates eddy currents in conductive materials; these currents have their own magnetic fields which we can push or pull with magnets. That’s where I left the project, though…a quick video where I waved a magnet around, some rough number-crunching to show that the induced forces were feasible for applications, and then I was out to let other members of the lab hash out the details. (That’s the fifth-year grad student for you!)
The cool news is that Ben has gone from my rough video to a much more carefully controlled demonstration. He’s generated attractive and repulsive forces in a bare piece of aluminum (not unlike the skin of a spacecraft), without touching it, and he’s working on characterizing the design space of his device. This is a critical step in figuring out how to go from proof of concept to a useful technology, and it’s a step I remember quite well. While Ben’s twitching pendulum might not look to you like the tractor beams from Star Trek, it is a clear and measurable experiment illustrating the device. I went from similar experiments in my first two-ish years of grad school to flight demonstrations in my third and fourth; I hope Ben follows a similar trajectory. And who knows – if some companies or space agencies take an interest, we may soon see spacecraft grappling asteroids and assembling components with eddy-current tugs!
Ben and some of the other Cornell Space System Design Studio grad students are keeping a blog about their technology research projects, which you can read here. I think it’s very cool to see what’s going on in the lab!
