There she blows (Image: ESA/Rosetta/NAVCAM)

When the Rosetta spacecraft sends its lander to the surface of a comet on 12 November, the lander will follow pre-arranged orders from Earth to touch down safely and send data home for analysis. But future spacecraft may be able to do it all on their own.

Kiri Wagstaff and her colleagues at the Jet Propulsion Laboratory in Pasadena, California, have developed software that can identify a plume of water or vapour on a celestial body’s surface, with the goal of directing another instrument to make follow-up observations.

Comets, asteroids and icy moons have all shown signs of venting plumes into space. But because these bodies are far from Earth and the jets are not always active, exploring them remotely is challenging. “The more the spacecraft can do without waiting for communication with Earth, the better they can explore – especially when they encounter activity that may be short-lived or only within viewing range for a short time,” Wagstaff says.


The researchers tested the software on unprocessed images of comet Hartley 2 and Saturn’s moon Enceladus. “We want to replicate what the instrument sees,” says team member David Thompson. The program looks for bright material outside the limb of the moon or comet, checks that the material meets up with the surface and is larger than a minimum size, and then determines if it is seeing a plume.

Wagstaff thinks an upcoming Europa orbiter mission would be a great opportunity to use this technology. But the software will be of even more benefit on future missions to the outer solar system and, eventually, planetary systems outside our solar system. “That will have to have to be an entirely autonomous operation,” she says.

Journal reference: The Astrophysical Journal, DOI:10.1088/0004-637X/794/1/43