[ak-47]

> Demo-2 is the final major test for SpaceX’s human spaceflight system to be certified by NASA for operational crew missions to and from the International Space Station.

The two astronauts along with the Falcon 9 will be docking with the ISS and then returning home. No crew swap is happening, which seems like a waste of energy. I get that SpaceX isn't "operationally certified", but is a crew swap inherently more risky?

[QuotedForTruth]

They will stay for 1 to 4 months. Its apparently partially dependent on whether they are prepared to launch the first actual crew mission on Aug 30.

A crew swap would require astronauts that are on station to return on the dragon, something they may not have trained for. So to do a swap, you'd probably have to take more than just the two test pilots up since they are likely required to pilot the capsule back down. Taking additional crew on the test flight would certainly be more risky to those additional lives.

[_Microft]

The mission was initially intended to be a short, crewed test flight, lasting only a week and a half but the spacecraft that was planned to be used for this was lost in a test accident.

Now they are flying on its successor capsule which is rated for much longer (iirc up to 110 days of) space operations. This allows NASA to extend the mission and lets the astronauts Hurley and Behnken help out on the ISS which are currently short on people iirc. They received training for this extended mission in the last few month.

[mabbo]

> The two astronauts along with the Falcon 9 will be docking with the ISS and then returning home

Just to be clear, the Falcon 9 is the booster that never gets to orbit. It's not going to the ISS- not moving fast enough to achieve orbit. Just the little Dragon spaceship on the nose of the rocket will get to the ISS.

> No crew swap is happening, which seems like a waste of energy. I get that SpaceX isn't "operationally certified", but is a crew swap inherently more risky?

Believe it or not, they've sent this 7-seat spacecraft to the ISS already (well, the same model) just to verify it could do it. It arrived empty, it went home empty (except for a plushy that stayed behind). The point is that SpaceX is going to be doing this maybe hundreds of times in the future, but the first time, they want to minimize the number of people that could die if something goes wrong.

Remember, this whole test would have been done 6 months ago except that the sister to this spaceship unexpected exploded during a simple ground test. This stuff is dangerous.

[ak-47]

Thanks!

[Diederich]

I understand your point, but it's just the way they do things. I believe it gives them more scheduling flexibility.

I read somewhere that the first 'operational' SpaceX <-> ISS will be in a couple of months.