Quote from: Johnnyhinbos on 05/23/2018 07:36 pmTrue - I remember that. However that’s not the current model. Dragon would likely have looked completely different without a pusher abort.
True - I remember that. However that’s not the current model.
Quote from: envy887 on 05/23/2018 05:28 pmQuote from: BarryKirk on 05/23/2018 05:23 pmWell just because the propulsive landing isn't an option any more, aren't the super dracos still in place to be used as Launch escape system and orbital maneuvering engines?Launch escape, yes. Orbital maneuvering, no. They use the regular Dracos for that.On what is yours statement based?The deorbit burns with the regular Dracos are pretty long, about 10 minutes IIRC.Using a pair, or a pair of pairs, of Super Dracos would shorten this dramatically.This might be beneficial for the lifetime of the to-be-reused Dracos, but might come at the expense of reentry accuracy.
Quote from: BarryKirk on 05/23/2018 05:23 pmWell just because the propulsive landing isn't an option any more, aren't the super dracos still in place to be used as Launch escape system and orbital maneuvering engines?Launch escape, yes. Orbital maneuvering, no. They use the regular Dracos for that.
Well just because the propulsive landing isn't an option any more, aren't the super dracos still in place to be used as Launch escape system and orbital maneuvering engines?
So the D2 brings all that hypergolic back to earth with them? That’s one benefit of using a tractor escape system - it gets ejected and therefore ceases to present a hazard to humans.
Quote from: clongton on 05/23/2018 07:38 pmQuote from: Johnnyhinbos on 05/23/2018 07:36 pmTrue - I remember that. However that’s not the current model. Dragon would likely have looked completely different without a pusher abort.Not so different:
Can someone confirm for me the total number of windows Dragon 2 is going to end up with? If there are now fewer, I need to update my (fictional) story in progress.
So no window on the actual hatch is now permanent, then?
So looking at the DM-1 Dragon pic, can we assume that the retractable nose cone has been deleted
along with propulsive landing and the landing legs? I would think that if it were to be permanently attached, it would be on there for the testing? what do you guys think?
Would the SuperDracos be suitable for ISS orbit raising, in the style of the Cygnus experiments being conducted on this visit?
Quote from: Joffan on 05/24/2018 06:07 pmWould the SuperDracos be suitable for ISS orbit raising, in the style of the Cygnus experiments being conducted on this visit?Using the SuperDracos would be a bad idea. For one thing, they are very powerful, and the ISS, and especially the ISS docking port, were not made to accept such thrust loads. For another, the SuperDracos have a lower ISP, so using them to do anything at all in orbit would be somewhat of a waste of fuel.The SuperDracos were intended to be used for heavy accelerations against gravity. That is, emergency aborts and landings.
Quote from: rpapo on 05/24/2018 06:46 pmQuote from: Joffan on 05/24/2018 06:07 pmWould the SuperDracos be suitable for ISS orbit raising, in the style of the Cygnus experiments being conducted on this visit?Using the SuperDracos would be a bad idea. For one thing, they are very powerful, and the ISS, and especially the ISS docking port, were not made to accept such thrust loads. For another, the SuperDracos have a lower ISP, so using them to do anything at all in orbit would be somewhat of a waste of fuel.The SuperDracos were intended to be used for heavy accelerations against gravity. That is, emergency aborts and landings.SuperDracos are definitely designed with thrust rather than Isp in mind, but also with the ability to throttle very deeply. So yes, it's absolutely the case that it wouldn't be the system you would build specifically for the purpose, but nevertheless if SuperDracos are up there with fuel to spare and nothing else to use it for, why not use it?The most telling argument against such a usage for me would be that the thrust can't be low enough for whatever limits are imposed on ISS reboosts. To be honest this seems unlikely - ISS is massive so even quite significant thrusts should not produce huge accelerations. But I stand in readiness as always to bow to better data.The docking port always seemed like a strange structure to accept reboost loads, but the Shuttle did it. However for argument's sake would the berthing port be more feasible?
The docking port always seemed like a strange structure to accept reboost loads, but the Shuttle did it. However for argument's sake would the berthing port be more feasible?
Quote from: Joffan on 05/24/2018 07:01 pmThe docking port always seemed like a strange structure to accept reboost loads, but the Shuttle did it. However for argument's sake would the berthing port be more feasible?No. Because the act of docking produces more loads on the interface than berthing.
Quote from: Jim on 05/24/2018 07:14 pmQuote from: Joffan on 05/24/2018 07:01 pmThe docking port always seemed like a strange structure to accept reboost loads, but the Shuttle did it. However for argument's sake would the berthing port be more feasible?No. Because the act of docking produces more loads on the interface than berthing.OK.I note that Cygnus is reboosting from the berthing interface, so presumably both are actually strong enough provided the loads can be managed.
Quote from: Joffan on 05/24/2018 10:06 pmQuote from: Jim on 05/24/2018 07:14 pmQuote from: Joffan on 05/24/2018 07:01 pmThe docking port always seemed like a strange structure to accept reboost loads, but the Shuttle did it. However for argument's sake would the berthing port be more feasible?No. Because the act of docking produces more loads on the interface than berthing.OK.I note that Cygnus is reboosting from the berthing interface, so presumably both are actually strong enough provided the loads can be managed.According to this: http://www.rocket.com/article/aerojet-rocketdyne-thrusters-help-cygnus-spacecraft-berth-international-space-station Cygnus uses 32x 7lbf small thrusters. So realistically load on the port would be a few kg, with the ability to be applied linearly. Much less than a person entering the pressurized vehicle.