I understand that the total energy is conserved during coasting, but does the long coast phase means there would be excess vertical velocity after S1 MECO? Then why the trajectory is not lowered during the first stage flight?Can someone explain why coasting for so long?
Quote from: hrissan on 04/17/2013 04:48 pmI understand that the total energy is conserved during coasting, but does the long coast phase means there would be excess vertical velocity after S1 MECO? Then why the trajectory is not lowered during the first stage flight?Can someone explain why coasting for so long?To get the vehicle at the proper orbital parameters (altitude and perigee) at burn out.
Cross-posting from party thread:Will this mark the first orbital flight for the NK-33? Yes, I know they're AJ-26, but from a heritage standpoint, will this be the first time this engine boosts an orbital payload?Thanks!
Apologies if this was asked already, but are there any holds in this countdown?
It's obviously a very different machine from the ULA launchers or Falcon-9. Would I be right in saying that the core will get almost all the way to orbit and the U/S is little more than a kick stage to get the perigee up?
You know, I don't understand the choice of a solid U/S. It seems to have all the wrong attributes for an U/S.Solids, IIUC, have a high "dry" weight, since the entire "tank" is thick walled. And in an U/S, every pound wasted is 100% at the expense of payload.Also, it burns to depletion, so you can't control end-of-burn, so I'd think that precision insertion is problematic.Lastly, it is not a high ISP solution.I always thought that solids are good as either high-thrust boosters, or BEO kick stages since they are simple and can last a long time in orbit.Anyone familiar with why they went with a solid U/S?
Quote from: Lar on 04/17/2013 09:05 pmU+F098 is a private use unicode character, not universally defined to mean anything. You shouldn't use it on the open web.
Anyone familiar with why they went with a solid U/S?
Quote from: meekGee on 04/17/2013 09:36 pmAnyone familiar with why they went with a solid U/S?IIRC, Antonio said they decided that doing a liquid first stage for the first time (for Orbital) was enough of a challenge, and that trying to simultaneously develop a liquid upper stage would have been biting off more than they could chew. An off-the-shelf solid was a lower technical and schedule risk proposition.
Are we looking at a wind limitation pending a strengthening or redesign?
Quote from: meekGee on 04/17/2013 09:36 pmYou know, I don't understand the choice of a solid U/S. It seems to have all the wrong attributes for an U/S.Solids, IIUC, have a high "dry" weight, since the entire "tank" is thick walled. And in an U/S, every pound wasted is 100% at the expense of payload.Also, it burns to depletion, so you can't control end-of-burn, so I'd think that precision insertion is problematic.Lastly, it is not a high ISP solution.I always thought that solids are good as either high-thrust boosters, or BEO kick stages since they are simple and can last a long time in orbit.Anyone familiar with why they went with a solid U/S?Cost and it is in the Antares threads that you should spend more time on.