Nanosatellite Will Search For Earth-like Planets Beyond Our Solar System
By James Mulroy
MIT has developed a new nanosatellite called ExoPlanetSat that has the sole purpose of finding Earth-like planets beyond our solar system that could support life. The ExoPlanetSat is expected to launch in 2012.
The nanosatellite has a volume of three liters and is 10 centimeters tall, 10cm wide, and 30cm long–about the size of a loaf of bread (I hope it’s whole wheat!). Although I don’t know for certain, I imagine that the MIT’s satellite is a part of the CubeSat program, initially started at Cal Poly, which typically allows for 10 by 10 by 10cm cubes and allows them to be added together to make large cubes like 10 by 10 by20cm (or like in this case, 10 by 10 by 30cm).
Unlike traditional large satellites which look at hundreds or thousands of stars at once, the ExoPlanetSat will look at a single star. While larger satellites are good at identifying a number of stars with potential Earth-like planets, they are not good at identifying the single one that really has the Earth-like planet (or at least that’s not their primary task). Sara Seager, a professor of Planetary Science and Physics, tells Technology Review that the ExoPlanetSat is not meant to replace the larger spacecraft (like NASA’s Kepler craft) but to instead compliment it, and vice versa.
To start with, the team will use the larger satellites to get a pool of potential stars. From that pool they will pick the most likely candidates, and will focus on those specific stars. Then the nanosatellite will search for planets by measuring the brightness change as a orbiting planet passes in front of the star. By calculating the amount by which the star dims, and by using pre-existing data about the size and brightness of the star (gained from a number of techniques like optical interferometry), the team can calculate the size of the star, and by using the rate of orbit the team can calculate the distance from the star.
But what’s so special about this nanosatellite? ExoPlanetSat must accurately measure a star’s brightness and according to Seager, incoming photons must hit the same fractions of pixel (on the light detectors) throughout the entire study of that star. If the Spacecraft is disturbed the measurements will be unreliable. Given the amount of precision required the team are using a highly advanced avionics package that will be used to stabalize the spacecraft and the detector counter. Apparently, the stabalization is so accurate that the human eye cannot sea the motion of the detector counter move–an order of magnitude better than any nanosatellite ever before.
The nanosatellites will cost a mere $600,000 once they go into production; the researchers plan to have a whole fleet. Get the full details at Technology Review.
Sounds great! Unfortunately, even if we do find Earth-like planets it’ll take dozens, if not hundreds, of years before our planet’s scientists have the money to go out and explore then first hand.