UK-US: Keeping space missions clean

Imagine the excitement. A space mission to Mars discovers microbial life! Scientists are beside themselves with anticipation. They pore over the first information sent back by their Mars rover. And then their excitement is replaced by disappointment, not to mention a little embarrassment. There's life all right, but it's from Earth - someone didn't disinfect that Mars rover properly. Oops.

Now scientists from the University of Leeds and NASA have developed a protocol to minimise the likelihood of such an event and published it in the journal Astrobiology. The protocol was developed for investigation of life in the Arctic - the Earth environment most similar to Mars - but is applicable for space exploration.

"We are trying to avoid a case of mistaken identity," says Professor Liane Benning, a bio-geochemist from the University of Leeds and co-author of the paper. "We know that on Mars, if present, any biological signatures will be extremely scarce. Therefore it is essential that we are able to minimise 'background noise' and to document just how clean our sampling devices really are before we use them," Benning said.

"We are now able to fully decontaminate sampling devices in the lab and field to null levels of detectable organic bio-signatures, before any samples are collected. Importantly, this new procedure doesn't just sterilise, it also cleans off any trace organic molecules of dead organisms."

The decontamination protocol involves a mix of chemicals and was tested at an international test site for NASA and the European Space Agency, "Search for Life" instrumentation on the island of Svalbard.

NASA research scientist Dr Jennifer Eigenbrode said the work would guide future planetary missions, especially to icy regions in the Solar System, such as Mars, or the moons of Jupiter and Saturn. The work was carried out during the 2005 and 2006 field seasons of the Arctic Mars Analogue Svalbard Expedition.