While microarrays may not be on board the European Space Agency's Exobiology on Mars mission when it launches later this decade, developers of the Life Marker Chip, which was designed specifically for the ExoMars mission, are positioning the array for use in future missions, according to a member of the development team.
Dan Evans, senior technical officer at Cranfield University in the UK, told BioArray News this week that cuts in funding for space missions, both in Europe and in the US, had led to the Life Marker Chip's potential "deselection" from the ESA's ExoMars mission, which is scheduled to launch in 2018.
Because of that, the team, which includes researchers from Cranfield, the UK's University of Leicester, and other institutions, is exploring other opportunities for the technology. "If the NASA [Curiosity Rover] finds organics on the surface of Mars, it seems that the next NASA launch would include some kind of LMC on board, and we think we are well-positioned for that," Evans said.
The UK Science and Technology Facilities Council agreed to fund the development of the Life Marker Chip in 2006 (BAN 2/21/2006), and it was to be included as part of a suite of analytical instruments located inside the planned ExoMars Rover.
According to Evans, the ExoMars Rover's drill would collect soil samples that would be dispersed to the array system, which would run a series of tests to detect a set of approximately 25 biomarkers to look for signs of extinct or extant life.
However, the Life Marker Chip's future has been complicated by budget issues in both Europe and the US. NASA in 2009 committed to the ExoMars mission, and had planned to contribute an additional rover to complement the ESA's rover, and rockets to get the mission into space and to land the rovers on the surface of Mars. However, the agency pulled out of ExoMars altogether earlier this year amid a 20 percent cut in planetary science programs, forcing the ESA to partner with the Russian Federal Space Agency to continue the planned launch, while scaling down the scope of its mission.
As the ESA-Russian rover will likely be smaller than originally planned, it is possible that the Life Marker Chip will be de-selected "due to payload mass and volume restrictions," said Evans.
Whether it takes part in the 2018 mission or not, the chip's developers believe that it will eventually be used to search for life on the Red Planet.
"The atmosphere in Mars is not particularly dense, and the surface has been battered by ultraviolet rays," Evans said. Therefore the chip was designed to detect molecules that could have survived the Martian environment and geological timescales. With those factors in mind, the Life Marker Chip development team, in collaboration with colleagues at University College London, selected content for the array.
The team settled on four main groups of molecules, Evans said: small apolar acyclic aliphatic molecules that are structurally unconstrained, have no functional groups, and map to extinct life biomarkers; small polar acyclic aliphatic molecules that are structurally constrained and have no functional groups; small polycyclic aromatic molecules that map to abiotic markers; and small polar molecules that map to extant life biomarkers.
According to Evans, the team envisioned integrating the system into the ExoMars rover. After the rover drilled into Mars' surface, samples would be collected, crushed, and then passed to the Life Marker Chip system automatically. The instrument would also contain a light source for fluorescent excitation and a CCD camera for detection, Evans said, and all results would be relayed back to ESA.
Evans recently discussed the chip at a Scienion workshop in Berlin. He said that his lab is not currently using Scienion's arrayers, but is considering outsourcing the production of the Life Marker Chip to the firm in the future. "Certainly their microarraying equipment is superior to what we have in the laboratory," he said.
Though NASA pulled out of ExoMars, Evans said that the chip development team has been encouraged by the success of NASA's Mars Science Laboratory mission, which landed the Curiosity Rover on the planet last month, with the hope that it will spur future missions.
"If Curiosity does find organics, it would seem unthinkable that NASA would not include something LMC-like on the next mission," Evans said. "What is unique about the LMC is that it has been designed for this purpose," he said of the chip's capabilities. "It is very hard to raise antibodies against the kinds of molecules that would be found on the surface of Mars, that are indicative of life, and that have been tested in a Mars-like environment," he said. "We do feel that we are ahead of the competition in that it could be used for Martian landing."
When asked what competition that could be, he said colleagues in Spain are developing similar microarray-based approaches for use in extreme environments on Earth.
And if it isn't selected for use in a Mars mission, he said the array could have a future in other applications on Earth.
"Our field of expertise is biodetection in extreme environments, so the possible applications for this are extremely diverse," said Evans. "Because it is designed for a Martian environment, it could be used in any extreme environment, such as volcanic settings or glaciers," he said.