Artist’s rendering of Stardust’s aerogel packs. Credit: NASA
NASA reported Monday that the aerogel grid that was carried by the agency’s Stardust spacecraft captured an amino acid, a finding that suggests that some of the building blocks of life may be present in much of the universe. The amino acid is glycine, the smallest of the amino acids.
“Glycine is an amino acid used by living organisms to make proteins, and this is the first time an amino acid has been found in a comet,” says Jamie Elsila of NASA’s Goddard Space Flight Center. Elsila’s quotes appear on the NASA website. “Our discovery supports the theory that some of life’s ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts.”
NASA sent out the Stardust in 1999. After traveling over three billion miles on a mission to capture material from the tail of comet Wild 2, part of the vehicle returned to Earth in early 2006. It contained a rack of aerogel packs, backed with foil, that were used as a sort of interstellar flypaper to snag minute samples of whatever materials were contained in Wild 2’s tail.
Since its return, NASA scientists have been fine-tuning their analytical techniques and carefully examining what is contained in the aerogel–foil traps. “We spent two years testing and developing our equipment to make it accurate and sensitive enough to analyze such incredibly tiny sample,” said Elsila.
It turns out that the glycine was detected relatively early, but researchers reacted with caution because they wanted to rule out the possibility of an Earthly source. “It was possible that the glycine we found originated from handling or manufacture of the Stardust spacecraft itself,” said Elsila.
New research, however, ruled out contamination by using isotopic analysis of the foil.