Handling toxic propellants is something you do every day when you go to the pump. That's why we have gas tanks. This is a non-issue.
And as far as solids fuels being safer than liquids, the body count comes down in favor of liquids.
Please name a propellant that is not toxic and can be stored for extended periods of time.
Quote from: notsorandom on 06/20/2014 03:31 amIndeed Falcon and Dragon are quite different from the COTS-D proposal and what Elon talked about before the Augustine committee. Of course they still thought parachutes were the way to go back then too.Parachutes, for capsule landing, are still the way to go. That's why the v2 still has them.Vertical landing is great, and I too look forward to the day when a stage flies back to the launch site and lands on its tail as God and Robert Heinlein intended, but for Dragon it's just a boondoggle. It's not "safe", it's not "how a 21st century spaceship should land" or whatever stupid sales gimmick they're using now. Considering that they're still going with toxic propellants, I don't think it's even sensible. Why the double standard? Because those stages are supposed to be able to be restacked and refly the same day (eventually), or at least the same week. There's absolutely no need for a crew vehicle to be able to do that. Ya want pinpoint landing? Buy an off-the-shelf GPS guided parachute. Ya want softer landings? Use airbags or a parawing.They'll never get back the years they've wasted developing the SuperDracos.
Indeed Falcon and Dragon are quite different from the COTS-D proposal and what Elon talked about before the Augustine committee. Of course they still thought parachutes were the way to go back then too.
Parachutes, for capsule landing, are still the way to go. That's why the v2 still has them.
So what is the CST-100's backup if their parachutes fail?
Quote from: QuantumG on 06/20/2014 09:05 amParachutes, for capsule landing, are still the way to go. That's why the v2 still has them.Redundant systems are the way to go. That's why the V2 still has them.So what is the CST-100's backup if their parachutes fail?Edit: to bring on topic.
V2 needs them in the case of a pad or in-flight abort.
Quote from: oiorionsbelt on 06/20/2014 04:48 pmSo what is the CST-100's backup if their parachutes fail?Multiple parachutes, same as Apollo, and same as Dragon. - Ed Kyle
Quote from: edkyle99 on 06/20/2014 05:14 pmQuote from: oiorionsbelt on 06/20/2014 04:48 pmSo what is the CST-100's backup if their parachutes fail?Multiple parachutes, same as Apollo, and same as Dragon. - Ed KyleSo, triple redundant systems on Dragon, Super Draco's, Parachutes and backup chutes. Seems more robust than just two sets of chutes like CST-100. DC's back up is?
DC's back up is?
Quote from: oiorionsbelt on 06/20/2014 07:46 pmDC's back up is?...pretty much like all the airplanes around the world landing with about 4.5 million passengers every day.
NASA intensively studied lifting bodies during the 1960s and 70s. There is a reason the agency chose to put wings on Shuttle. - Ed Kyle
Quote from: dchill on 06/21/2014 02:39 amQuote from: oiorionsbelt on 06/20/2014 07:46 pmDC's back up is?...pretty much like all the airplanes around the world landing with about 4.5 million passengers every day. Which airlines use lifting bodies?NASA intensively studied lifting bodies during the 1960s and 70s. There is a reason the agency chose to put wings on Shuttle. - Ed Kyle
Oh come on, Ed. You know very well the reason they used wings per se rather than a lifting body: size/mass of the vehicle in the first place; cargo down-mass requirements, and cross-range. Had they gone straight from their small lifting body experiments to an operational space vehicle, it would have looked very much like DC does.
They didn't had fly-by-wire technology as mature and reliable as today. That's true. But they shouldn't had gone to a jack of all trades super vehicle with 60% of the already optimists budgets for full development. In any case, none of this is an issue for CST-100.Am I remembering right that the stock CST-100 pressure vessel doesn't have enough clearance for a CBM? I understand that if you take the petals out of the IDA you could pass a 1.2m cylinder. But will the APAS-IDA adapter have enough internal clearance?
Quote from: baldusi on 06/22/2014 10:43 pmThey didn't had fly-by-wire technology as mature and reliable as today. That's true. But they shouldn't had gone to a jack of all trades super vehicle with 60% of the already optimists budgets for full development. In any case, none of this is an issue for CST-100.Am I remembering right that the stock CST-100 pressure vessel doesn't have enough clearance for a CBM? I understand that if you take the petals out of the IDA you could pass a 1.2m cylinder. But will the APAS-IDA adapter have enough internal clearance?CBM dimensions are not native, and were not a mojor consideration. It's on the Boeing site in a pdf on another subject alltogether. I'll bet with slight modification you could get real close. I don't think the cone shape and the accessory bays allow it though.1.2m is a good approximation, it depends on the pettal itteration, that's still changing. But by design all pettals may be removed to accomodate the maximum diameter the rings and systems will accomodate. It's another reason why some designs have a second internal ring, with fluid transfer and additional electrical connections capabilities. I have no idea where they stand on this design feature, the ILIDS and IDA only show the one ring.
Quote from: Darren_Hensley on 06/23/2014 08:59 amQuote from: baldusi on 06/22/2014 10:43 pmThey didn't had fly-by-wire technology as mature and reliable as today. That's true. But they shouldn't had gone to a jack of all trades super vehicle with 60% of the already optimists budgets for full development. In any case, none of this is an issue for CST-100.Am I remembering right that the stock CST-100 pressure vessel doesn't have enough clearance for a CBM? I understand that if you take the petals out of the IDA you could pass a 1.2m cylinder. But will the APAS-IDA adapter have enough internal clearance?CBM dimensions are not native, and were not a mojor consideration. It's on the Boeing site in a pdf on another subject alltogether. I'll bet with slight modification you could get real close. I don't think the cone shape and the accessory bays allow it though.1.2m is a good approximation, it depends on the pettal itteration, that's still changing. But by design all pettals may be removed to accomodate the maximum diameter the rings and systems will accomodate. It's another reason why some designs have a second internal ring, with fluid transfer and additional electrical connections capabilities. I have no idea where they stand on this design feature, the ILIDS and IDA only show the one ring.Crewed vehicles must be able to undock quickly and without robotics and CBM assistances. CBM is *not* an option. Move on
how old is that CBM design anyhow?
Quote from: Prober on 06/23/2014 05:11 pmhow old is that CBM design anyhow? The mechanical design passed the Space Station Freedom Work Package 1 PDR at MSFC in the spring of 1993. The general dimensions came well before that (circa 1988 towards the end of Phase B studies).