Robots sustain solar system learning

Robots and orbiting satellites are what sustain efforts to learn more about our solar system.

Satellites are studying Mercury, Venus and Mars in the inner solar system while the outer solar system's gas giants Jupiter and Saturn and their many moons are being scrutinised by other satellites including a newcomer, Juno, due to arrive by 2016.

There is virtually no other way to study of the solar system's planets given the difficulties of getting humans safely to and from these planets, a presentation at the ongoing American Association for the Advancement of Science in Boston heard.

A collection of scientists described the latest findings from a collection of satellites during a session entitled: "Interplanetary Robots: The Latest from Mars and Other World".

The rover Curiosity was seldom far from the news given its current activities underway on the surface of Mars, said Prof John Grotzinger at the California Institute of Technology and project scientist for the Mars Science Laboratory.

Only days ago it successfully drilled into a rock and took samples of the dust it produced. It will take another week or two to confirm whether the dust has made it past the chimera rock crusher and into the experiments that will test the rock's chemistry.

"We think that we got a rock that has had a lot of interaction with water," he said. This could provide evidence that liquid water was present for long periods in Martian history.

Dr David Blewett of Johns Hopkins University discussed the findings about Mercury flowing from the Messenger spacecraft which has been orbiting th closest planet to the sun for almost two years. "Mercury was the last of the planets to be studied by a satellite," he said. Messenger has been carrying out a detailed study of Mercury which has shown to be a dynamic world with a number of unexpected discoveries, he said.

Dr Amanda Hendrix of the Planetary Science Institute, Tucson, Arizona talked about the ongoing Cassini satellite mission to explore Saturn and its many moon. There are at least 60 of them but most of the focus is on Titan and Enceladus. Both could potentially harbour life given they have ice-covered seas. Enceladus has geothermal activity and this pushes out a plume of water that can be sampled by the satellite, she said.

Dr Robert Pappalardo of the Jet Propulsion Lab in Pasadena described similar seas that are likely to exist on the moons of Jupiter, Europa Ganymede and Callisto. "Is there life somewhere in the solar system aside from the earth and where could it exist," he asked. Jupiter's moons are a good bet because of the seas kept liquid below a surface of ice.

He added however that very soon the stream of information about the outer solar system will halt as Juno and Cassini go out of service. "The US has no plans to explore the outer solar system after 2017," he said.