3 ms·
Also, the rocket will be falling at its terminal velocity, having lost the rest of its speed to air drag. Even without parachutes (and they don't intend to carr
by puetzk 13y ago
Also, the rocket will be falling at its terminal velocity, having lost the rest of its speed to air drag. Even without parachutes (and they don't intend to carry any), that's only ~120 m/s - the upper stage and payload are gone, the 1st stage has big tanks but only a little fuel left, so its density is low. The final burn for propulsive landing only has to cancel that last little bit.
- jlgreco 13y agoYup, air resistance works with you on the way down, not against you, and it is courteous enough to start small and work itself up when you are on the way down.
- troels 13y agoDoesn't it result in a lit of heat from the friction? Or is that only a problem at much higher speeds?
- jlgreco 13y agoThere will be heat; even the suborbital Mercury-Redstone missions needed heat shields. I don't know how SpaceX is planning on handling that. Maybe the trajectory they put themselves on is going to be slow enough to survive reentry using just the main engine nozzles as make-shift heat shields?
- antubbs 13y agoCan't speak to the plan for the second stage (which will do a once-around and de-orbit if I understand correctly), but the first stage will not be following a ballistic trajectory and re-entry like a normal suborbital launch. Its goal is to return to the pad a few minutes after launch.
- jlgreco 13y agoI suspect they will still do a single burn somewhere around apogee of the first stage; if I understand correctly they are well into their gravity turn by the time it separates so they'll have some horizontal velocity they will need to get rid of. Maybe they are going to push the gravity turn later into the flight so that the first stage doesn't participate in that as much?