[EricH]

Originally Posted by dodar

But each company is compared based and competes on the same standards set forth by the one offering the contract.

I want to expand on this one a bit. I think you're on the right track, but you're missing something.

The one offering the contract may be regulated by other standards, that HAVE to be passed on to their contractors. For example, ITAR. For a U.S. company that doesn't deal with potential weapons applications, no big deal. For a U.S. company that deals with weapons, potential weapons, and their applications, HUGE deal. And, in short, ITAR means for the latter company that foreign parts/persons are going to require lots of paperwork, if they can even show up at all. (I won't even go into sanctions...) Oh, and did I mention: Much of the U.S. space program has been based on Air Force research for weapons systems.

Because the one offering the contract (sponsorship) in this particular case happens to be a government agency (NASA), ITAR and/or other standards regarding dealings with non-U.S. entities almost certainly apply. NASA has to comply with those, and the simplest way (and maybe the only way) is to offer to only U.S. entities.

tl;dr: NASA may want to offer the sponsorship to everybody that wins the EI, but the rest of the U.S. government probably has a regulation against it somewhere. NASA's hands are therefore tied in that respect.