Watch out for stowaways (Image: Adrian Mettauer)

NO WONDER life is crammed into every niche on the planet. DNA can survive blasting into space and back on the outside of a rocket.

Cora Thiel at the University of Zurich in Switzerland and her colleagues mixed small loops of DNA, known as plasmids, with a liquid solution and painted it on the outside of a rocket. It flew for 13 minutes, reaching a height of 270 kilometres before returning to Earth.

Although atmospheric friction heated the DNA to more than 1000 °C during re-entry to the atmosphere, Thiel recovered molecules from many different points on the rocket. The highest level of survival was seen inside the grooves of screw heads, where 53 per cent of plasmids made it.


The DNA of the plasmids encoded proteins for antibiotic resistance and fluorescence. When the team implanted the plasmids into E. coli and mouse cells, 35 per cent gave the cells these properties, suggesting the DNA was fully functional (PLoS One, DOI: 10.1371/journal.pone.0112979).

The result is exciting for fans of panspermia, the idea that life on Earth was seeded by microbes from space – although it is unclear whether DNA would survive such long journeys.

The result is exciting for fans of the idea that life on Earth was seeded by microbes from space

But it could also pose a problem for finding alien life. When space agencies send robot explorers to other planets, they give them a deep clean to remove all Earthly signs of life. The idea is to avoid contaminating another world, which would make it more difficult to detect genuine aliens. Thiel says her work suggests agencies should coat their robots with artificial DNA before cleaning, to confirm it has all been removed.

“This is an interesting and provocative study,” says Christopher Carr at the Massachusetts Institute of Technology. Unprotected DNA in space would probably be destroyed by UV radiation, he says, but it is worth re-examining our methods of sterilising spacecraft.

This article appeared in print under the headline “DNA survives round trip to space on rocket”