Quote from: corrodedNut on 05/21/2014 04:54 pmSounds like they will use the Grasshopper pad unless they decide they will need a dedicated pad, which will be a 40' square pad near the SuperDraco facility. The report describes this as the "DragonRider test area".No, the report indicates that it will be a separate pad:Quote"The proposed launch pad would be 40 ft by 40 ft located approximately 0.32 mile north of the Grasshopper launch pad."
Sounds like they will use the Grasshopper pad unless they decide they will need a dedicated pad, which will be a 40' square pad near the SuperDraco facility. The report describes this as the "DragonRider test area".
"The proposed launch pad would be 40 ft by 40 ft located approximately 0.32 mile north of the Grasshopper launch pad."
Quote from: JBF on 05/21/2014 04:42 pmQuote from: Jarnis on 05/21/2014 04:33 pmFreefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man Can anyone model the G-Force curve on that? It sounds like a rough ride.If anyone can guess the terminal velocity of the capsule, it should be easy to calculate. If the G-load is evenly spread over 5 seconds, it might not be too bad.
Quote from: Jarnis on 05/21/2014 04:33 pmFreefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man Can anyone model the G-Force curve on that? It sounds like a rough ride.
Freefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man
Quote from: Lars_J on 05/21/2014 04:49 pmQuote from: JBF on 05/21/2014 04:42 pmQuote from: Jarnis on 05/21/2014 04:33 pmFreefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man Can anyone model the G-Force curve on that? It sounds like a rough ride.If anyone can guess the terminal velocity of the capsule, it should be easy to calculate. If the G-load is evenly spread over 5 seconds, it might not be too bad.For a very first order estimate I get a terminal velocity of ~150 m/s given a total mass of 17,000 lbs (dry mass plus 3000 lbs of fuel) and a drag coefficient of 0.8.
All these 31 flavors of Dragon, are giving me a brain freeze. How does this craft, DragonFly RLV, compare with the May 29 Dragon mk2 reveal, and CCdev? Does NASA even know what craft they would get if they awarded SpaceX the win.
Quote from: sublimemarsupial on 05/21/2014 05:01 pmQuote from: Lars_J on 05/21/2014 04:49 pmQuote from: JBF on 05/21/2014 04:42 pmQuote from: Jarnis on 05/21/2014 04:33 pmFreefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man Can anyone model the G-Force curve on that? It sounds like a rough ride.If anyone can guess the terminal velocity of the capsule, it should be easy to calculate. If the G-load is evenly spread over 5 seconds, it might not be too bad.For a very first order estimate I get a terminal velocity of ~150 m/s given a total mass of 17,000 lbs (dry mass plus 3000 lbs of fuel) and a drag coefficient of 0.8.A 5 second burn to brake from 150 m/s would result in an average of ~3Gs of deceleration.
Spacex will need to address the problems of dealing with Hydrazine/NTO in case of accidents.keep the cows upwind or something.
This is not your standard LAS... all control elements here for reusable (Mars or Moon) landing vehicle, For ascent, vehicle will obviously need more propulsion and more than 25(+residuals) seconds of fuel.
Quote from: Lars_J on 05/21/2014 05:08 pmQuote from: sublimemarsupial on 05/21/2014 05:01 pmQuote from: Lars_J on 05/21/2014 04:49 pmQuote from: JBF on 05/21/2014 04:42 pmQuote from: Jarnis on 05/21/2014 04:33 pmFreefall, 5 sec burn at the last moment, soft touchdown.Whoever will ultimately ride aboard that kind of flight profile (obviously not during these tests) is a brave man Can anyone model the G-Force curve on that? It sounds like a rough ride.If anyone can guess the terminal velocity of the capsule, it should be easy to calculate. If the G-load is evenly spread over 5 seconds, it might not be too bad.For a very first order estimate I get a terminal velocity of ~150 m/s given a total mass of 17,000 lbs (dry mass plus 3000 lbs of fuel) and a drag coefficient of 0.8.A 5 second burn to brake from 150 m/s would result in an average of ~3Gs of deceleration.Doing some more math on those assumed figures it looks like the start of the landing burn starts about 375 meters in altitude. That assumes a deceleration of about 3g's and initial velocity of 150 m/s. If something should go wrong at the start of the burn like a stuck valve is that enough time and altitude to pop a parachute out?
I think there is a misunderstanding somewhere. The "Propulsive Assist" (includes parachutes) has the engines firing for ~5 seconds (starting at a AGL height of 98ft) while the full-propulsive landings have the engines firing for 12.5 seconds. So the 150 m/s terminal velocity is likely slowed over 12.5 seconds rather than just 5sec. The terminal velocity under parachute should be much less than 150m/s shouldn't it?
Quote from: meadows.st on 05/21/2014 05:35 pmI think there is a misunderstanding somewhere. The "Propulsive Assist" (includes parachutes) has the engines firing for ~5 seconds (starting at a AGL height of 98ft) while the full-propulsive hopping landings have the engines firing for 12.5 seconds. So the 150 m/s terminal velocity is likely slowed over 12.5 seconds rather than just 5sec. The terminal velocity under parachute should be much less than 150m/s shouldn't it?The quoted full propulsive landing in this thread states "There would be a period of free fall and then the engines would fire for approximately 5 seconds and the RLV would make a powered landing." I agree this seems odd, perhaps it is a typo and the 5 second burn is indeed parachute-assisted. That would make more sense.
I think there is a misunderstanding somewhere. The "Propulsive Assist" (includes parachutes) has the engines firing for ~5 seconds (starting at a AGL height of 98ft) while the full-propulsive hopping landings have the engines firing for 12.5 seconds. So the 150 m/s terminal velocity is likely slowed over 12.5 seconds rather than just 5sec. The terminal velocity under parachute should be much less than 150m/s shouldn't it?