Sealing wax and string?

SEARCHING for planets going around stars other than the sun has not been cheap. CoRoT (Convection Rotation et Transits planétaires), a French planet-hunting satellite that was operational from 2007 to 2013, cost €175m ($220m). Kepler, an American one that was launched in 2009 and went wrong in 2013, cost $600m. But a group of graduate students at Stuttgart University, in Germany, think they can do better. A lot better. They propose to do the job for €7m.

Johannes Mathies, Steffen Mauceri, Lukas Pfeiffer and Marco Vietze are part of a movement which believes that, because electronics have become smaller, better and cheaper, satellites can follow suit, and thus cease to be the preserve of governments and large corporations. They call their proposal (details of which are published in Acta Astronautica) the Small Satellite for Exoplanetary Transit Observation, or SSETO.

SSETO would weigh less than 150kg (CoRoT, by contrast, weighs 630kg and Kepler 1,041kg), yet it would pack two telescopes (one for finding planets; the other for observing cosmic dust, from which planets form) and also carry a device designed to analyse particles of dust it encountered in orbit. The planet-finding telescope would be, in essence, an 8.4 megapixel camera with a lens 40cm across. It would be able to detect, from the diminution of starlight caused by a planet’s passage in front of its parent star, worlds as small as five times the size of Earth going around stars of 16th magnitude (a 6,000th as bright as the faintest star the naked eye can see). That is as good as CoRoT, though not as good as Kepler, which has observed planets as small as the Moon (ie, with a quarter of Earth’s diameter).

Besides the onward march of technology, the four friends have three other reasons to think they can stay within budget. One is that they are more willing than a national space agency would be to accept the possibility of failure. They propose, for example, to buy sensors for the camera from the firm that supplied CoRoT, but instead of having it make special spaceworthy ones, they would purchase them off the shelf and customise and test them for spaceworthiness themselves.

The second reason for the low budget is that their craft would be so light that it could piggyback on someone else’s launch, instead of having to have an entire rocket to itself. The third reason is that the mission’s ground staff would mostly be graduate students and lowly paid academics at the beginnings of their careers, rather than civil servants. This would include the engineers doing the customisation and spaceworthiness tests, whose future job prospects would be considerably enhanced by the mission’s success and who would thus have a strong incentive to get things right.

The Institute of Space Systems at Stuttgart, of which the four friends are members, plans to launch a minisatellite called the Flying Laptop next year, to prove it is capable of running a mission. If that goes well, and the team can raise enough money, then SSETO might follow two or three years later.