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#420
by
Jim
on 20 Jun, 2014 13:26
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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.
Quite wrong. There are no ill effects due to short term exposure to fumes while fueling or being next to an operating car. Same goes for getting splashed by gasoline when the nozzle "burps" while fueling. It is quite the opposite with H2H4 or N2O4.
Also, gasoline is not a monopropellant and doesn't decompose when exposed to contaminates.
And as far as solids fuels being safer than liquids, the body count comes down in favor of liquids.
Wrong. Body count is not relevant, since it is more of a function of the vehicle's capacity vs number of incidents. And the "one" incident did not have an escape system, so it doesn't even count.
Please name a propellant that is not toxic and can be stored for extended periods of time.
Ethanol, GH2, GCH4, etc. There are many that can be stored and are non toxic in short term exposures.
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#421
by
notsorandom
on 20 Jun, 2014 14:41
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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.
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.
Sorry I should have been more specific. I meant parachutes on the Falcon. At any rate the CTS-100 dosn't seem to be all that far behind Dragon at this point. It is a viable contender.
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#422
by
oiorionsbelt
on 20 Jun, 2014 16:48
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Parachutes, 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.
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#423
by
edkyle99
on 20 Jun, 2014 17:14
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So what is the CST-100's backup if their parachutes fail?
Multiple parachutes, same as Apollo, and same as Dragon.
- Ed Kyle
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#424
by
AnalogMan
on 20 Jun, 2014 18:33
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Parachutes, 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.
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#425
by
Elmar Moelzer
on 20 Jun, 2014 18:48
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V2 needs them in the case of a pad or in-flight abort.
And in case the engines fail to start prior to powered landing.
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#426
by
oiorionsbelt
on 20 Jun, 2014 19:46
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So what is the CST-100's backup if their parachutes fail?
Multiple parachutes, same as Apollo, and same as Dragon.
- Ed Kyle
So, 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?
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#427
by
Rocket Science
on 20 Jun, 2014 20:17
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So what is the CST-100's backup if their parachutes fail?
Multiple parachutes, same as Apollo, and same as Dragon.
- Ed Kyle
So, 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?
HL-20 had a proposed chute which is seen as not required for DC... Its lifting body generates enough cross range and recall that reasonably low 161 kts landing speed during ALT 1.
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#428
by
dchill
on 21 Jun, 2014 02:39
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DC's back up is?
...pretty much like all the airplanes around the world landing with about 4.5 million passengers every day.
If the world had millions of people trying to land using rocket thrusters and back-up parachutes every day, the news would probably take 15 minutes longer to get done listing all the fatalities.
Structure is inherently more reliable than fabric tucked up in a ball and/or rocket motors (given nearly equivalent TPS issues on the initial reentry phase - and if you're only coming back from LEO).
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#429
by
edkyle99
on 21 Jun, 2014 14:04
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DC'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
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#430
by
rayleighscatter
on 21 Jun, 2014 15:03
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NASA intensively studied lifting bodies during the 1960s and 70s. There is a reason the agency chose to put wings on Shuttle.
- Ed Kyle
Two main reasons. One being the USAF wanted to be able to make once around polar orbits, which required a very high crossrange. Two was that the complex shape of the body would result in difficult payload bay dimensions and subsytem layouts. Number one was the real driver though.
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#431
by
Herb Schaltegger
on 21 Jun, 2014 15:50
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DC'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.
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#432
by
edkyle99
on 21 Jun, 2014 21:52
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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.
NASA traded lifting bodies with winged designs for Shuttle during the early studies, but went with wings very early. The add-on USAF cross range requirements forced use of a double-delta wing rather than the original straight wing, but lifting bodies were already out of it by then. The early lifting bodies had stability problems and landed hot. They got better later.
- Ed Kyle
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#433
by
baldusi
on 22 Jun, 2014 22:43
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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?
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#434
by
Darren_Hensley
on 23 Jun, 2014 08:59
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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?
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.
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#435
by
erioladastra
on 23 Jun, 2014 16:49
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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?
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
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#436
by
Prober
on 23 Jun, 2014 17:11
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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?
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?
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#437
by
baldusi
on 23 Jun, 2014 19:11
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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?
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
He just answered my question. And I was trying to find out the suitability for CRS 2 of CST-100. Let's remember that their pressure vessel is made out of a single billet, formed and machined. Thus, I understand that making adaptations is not that easy. And CBM is very important to CRS 2.
As stated before, adding an unpressurized section is not so simple with the CST-100, and the CBM seems incompatible. Which is a shame given that it is a lot roomier inside. Save for the CBM CST-100 would make an amazing pressurized cargo transport.
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#438
by
Herb Schaltegger
on 24 Jun, 2014 00:11
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how 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).
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#439
by
A_M_Swallow
on 24 Jun, 2014 00:33
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how 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).
The CBM is great at joining modules together permanently - much easier than welding them. Unfortunately, unlike LEGO bricks, it does not pull apart easily.
