I'd not heard of this project specifically before - Balloon's get a lot of mention for Mars exploration, but given the thin atmosphere, you need a HUGE balloon for a small payload - there's still scope for something interesting though, or people wouldnt be putting plans together :) I like their 'Go around to ground' idea - anyone who's played orbiter and miss-judged re-entry will have probably done this themselves, skipped their way around the atmosphere for almost a full orbit.

re: Stardust@Home - not sure what you mean by selection, it's open for everyone to apply and I'd hope that most of the people here would - never know, you might find one :)

Doug