This week, the NanoSail-D mission successfully deployed from FASTSAT. This is, apparently, the first time a nanosatellite has ejected from a microsatellite.
(In spacecraft lingo, engineers grabbed the term “microsatellite” to just mean “a small satellite,” where “small” was in comparison to the spacecraft with masses of thousands of kilograms. But they kept the relationship between the metric prefixes. So a “microsatellite” is about 100 kg or less, and a “nanosatellite” is about 10 kg or less. This is unfortunate for, say, my research group, because our proposed millimeter- or micron- scale spacecraft would have to be named something inconvenient to say, like “yoctosatellites.” Anyway.)
I think NanoSail-D is exciting for two reasons. First, it’s only the second solar sail mission to not explode on launch, after JAXA’s ICAROS mission. (The Planetary Society tried to launch a solar sail five years ago, but the converted ICBM launch vehicle malfunctioned.) Solar sails are a propulsion system that could allow spacecraft to move around the Solar System without expending propellant, so they would be a great technology for getting from planet to planet efficiently. The downside is that solar sailing takes a long time, but fortunately, robots can have long lives and a lot of patience. More solar sails may mean more robotic missions to planets, asteroids, and moons all over the place, which is a good thing for science!
The other reason why NanoSail-D is cool is this microsatellite-deploying-a-nanosatellite idea. Microsatellites are small and low-cost enough to have a pretty rapid development cycle, and spacecraft engineers are less averse to trying out riskier, newer technologies on microsatellites. FASTSAT is a great example: it’s a technology demonstrator mission, a spacecraft devoted entirely to trying out new things. Nanosatellites can be even faster and cheaper to build, so much so that it’s pretty common for universities to build CubeSat projects and you can buy components to build a fully-functional CubeSat off the internet for $100,000 or less.
So with FASTSAT and NanoSail-D, we have a relatively cheap spacecraft with a rapid development cycle that includes cool new technologies – and it launches an even cheaper spacecraft with even riskier technologies, including one that could allow interplanetary trajectories.
These are the ingredients we need to get probes all over the Solar System, and these are the design philosophies that push the envelope of spacecraft engineering.