<snip 'how much margin'>There should be enough for propulsive landing (plus margin) and also orbital maneuvering (plus margin), since the nominal mission profile included both orbital maneuvering and propulsive landing.Propulsive landing probably required over 500 m/s, and now that should be fully available on a nominal mission.
Quote from: envy887 on 05/28/2018 03:43 pmQuote from: Nomadd on 05/28/2018 03:27 pmQuote from: Comga on 05/27/2018 05:28 pmThat made NO sense. The discussion centered on the availability of fuel, including how OATK can modify Cygnus to carry MORE fuel. However, with NASA demanding that Dragon 2 lands under parachutes in the ocean the abort fuel is fully avaiilable for station reboost. After deorbit it it’s probably more of a liability than a benefit. It would be better to burn it on orbit particularly with engines that face fully away from the ISS. And the axial port is better for reboost as you said. Abort fuel wouldn't be "fully" available. It would be used for regular orbital maneuvering if not used for abort. I don't know how much extra they might have.There should be enough for propulsive landing (plus margin) and also orbital maneuvering (plus margin), since the nominal mission profile included both orbital maneuvering and propulsive landing.Propulsive landing probably required over 500 m/s, and now that should be fully available on a nominal mission.And in round numbers, 500m/s delta-v for a Dragon would translate into about 7 m/s delta-v for the ISS, and a 12km orbit raise. Not bad.
Quote from: Nomadd on 05/28/2018 03:27 pmQuote from: Comga on 05/27/2018 05:28 pmThat made NO sense. The discussion centered on the availability of fuel, including how OATK can modify Cygnus to carry MORE fuel. However, with NASA demanding that Dragon 2 lands under parachutes in the ocean the abort fuel is fully avaiilable for station reboost. After deorbit it it’s probably more of a liability than a benefit. It would be better to burn it on orbit particularly with engines that face fully away from the ISS. And the axial port is better for reboost as you said. Abort fuel wouldn't be "fully" available. It would be used for regular orbital maneuvering if not used for abort. I don't know how much extra they might have.There should be enough for propulsive landing (plus margin) and also orbital maneuvering (plus margin), since the nominal mission profile included both orbital maneuvering and propulsive landing.Propulsive landing probably required over 500 m/s, and now that should be fully available on a nominal mission.
Quote from: Comga on 05/27/2018 05:28 pmThat made NO sense. The discussion centered on the availability of fuel, including how OATK can modify Cygnus to carry MORE fuel. However, with NASA demanding that Dragon 2 lands under parachutes in the ocean the abort fuel is fully avaiilable for station reboost. After deorbit it it’s probably more of a liability than a benefit. It would be better to burn it on orbit particularly with engines that face fully away from the ISS. And the axial port is better for reboost as you said. Abort fuel wouldn't be "fully" available. It would be used for regular orbital maneuvering if not used for abort. I don't know how much extra they might have.
That made NO sense. The discussion centered on the availability of fuel, including how OATK can modify Cygnus to carry MORE fuel. However, with NASA demanding that Dragon 2 lands under parachutes in the ocean the abort fuel is fully avaiilable for station reboost. After deorbit it it’s probably more of a liability than a benefit. It would be better to burn it on orbit particularly with engines that face fully away from the ISS. And the axial port is better for reboost as you said.
jacqmans, aren't the panels at eye level when dragon is rotated horizontal? The photo appears as if she is looking (relative) up.I'm wondering when the crew is in zero-g if they are looking straight ahead or looking up at the panels.
It seems like handling a chute failure scenario would be no more than a little software if you had the fuel. What reason could there possibly be for not using an available means to slow down if you're headed for a terminal (pun intended) velocity impact?
Quote from: Nomadd on 05/30/2018 07:47 pm It seems like handling a chute failure scenario would be no more than a little software if you had the fuel. What reason could there possibly be for not using an available means to slow down if you're headed for a terminal (pun intended) velocity impact?Propulsive landing as a backup to the redundant parachutes?That's quite a stretch. .
Quote from: Comga on 05/30/2018 07:55 pmPropulsive landing as a backup to the redundant parachutes?That's quite a stretch. Why? You have the engines. All you'd have to do is fire them. We're not talking about adding legs or anything. If they'd added a few simple commands in the early days, they might have saved the CRS-7 capsule and payload.
Propulsive landing as a backup to the redundant parachutes?That's quite a stretch.
Quote from: Comga on 05/30/2018 07:55 pmQuote from: Nomadd on 05/30/2018 07:47 pm It seems like handling a chute failure scenario would be no more than a little software if you had the fuel. What reason could there possibly be for not using an available means to slow down if you're headed for a terminal (pun intended) velocity impact?Propulsive landing as a backup to the redundant parachutes?That's quite a stretch. . Why? You have the engines. All you'd have to do is fire them. We're not talking about adding legs or anything. If they'd added a few simple commands in the early days, they might have saved the CRS-7 capsule and payload.
(I have been tryin to guess how the Dragon would sense the altitude with enough precision to slow to a stop at zero altitude. Where would they mount a radar? Could they use a vision system looking out the window?)
carrying enough extremely volitile hypergolic fuel aboard a capsule carrying humans - enough to light four extremely thirsty super Draco’s to slow the D2 from freefall to standstill -