I'm trying to figure out exactly what this is, to be honest. To me it looks like their version of Amazon Web Services, for sharing compute resources exclusively within their community. But I can't tell whether it's just providing secure hardware to throw VMs at or if they've built the support infrastructure like a fault tolerant file system as well.

Edit: From http://nebula.nasa.gov/services/ it appears they have a distributed file system, but otherwise it's simply a set of networked machines.