You need a lot of storage when you're snapping 100,000 photographs every half hour for nearly four years. That's the task ahead for NASA's Kepler Mission, which after launching in February 2009 will search for Earth-size planets by taking images of 100,000 solar systems over and over again through to 2012.
Because planets are too small to photograph directly, NASA scientists will look for dark blips on faraway stars that could indicate a planet passing in front.
Storage is "absolutely critical to the mission", says Chris Middour, deputy manager of the Kepler Operations Science Centre at NASA's Ames Research Centre in Mountain View, California.
"We're looking for other planets like Earth," Middour says. "Right now, we're running 30 terabytes and we expect that to go up to 100 pretty soon."
NASA considered several storage vendors and chose a 3Par storage array which contains Serial Advanced Technology Attachment (SATA) drives, but can be upgraded to Fibre Channel drives in the future if NASA needs faster performance. "We may well go to [Fibre Channel] in the near future," Middour says.
3Par management features helped win NASA over, including a snapshot feature that gives NASA an image of what its storage looks like at any given time and keeps it intact as a separate volume. Creating new storage partitions can also be done with the click of a button, Middour says.
The research centre is using Dell servers with multicore Intel chips to run an Oracle database and custom-built software that will analyse the photos.
"We have a processing pipeline that examines these photographs that's really complex, and has four large racks of equipment," Middour says. "Scalability was one of the biggest challenges. Being able to run an automated pipeline for all these hundreds of thousands of images was challenging in terms of storage needs and memory usage, and even heat in the room. We had air conditioning issues, all the problems an IT datacentre has today."
Kepler is NASA's first mission capable of finding planets the size of Earth and smaller. Specifically, NASA wants to find planets between half and twice the size of Earth orbiting stars in the "habitable zone" where liquid water and potentially life could exist.
NASA expects to find between 50 and 640 such planets.
Weighing more than 2,000 pounds, the Kepler space telescope will orbit the Sun, shifting its position periodically so that it can view the same star field for the entire mission.
Kepler will have to detect planetary transits as brief as two hours out of an entire year.
"We're looking for drops in the light from the star when that planet comes between us and the Earth," Middour says. "The planet will block just a little bit of light."