Quote from: Jim on 01/28/2014 02:50 pmQuote from: thydusk666 on 01/28/2014 02:22 pmAssuming the 401/402 can lift the CST-100 to LEO, how much delta-V/altitude increase would be provided by SRBs, in either 1/2/3/4/5 configuration?No, because there is no need for different delta-V/altitudesAre you suggesting that CST-100 is built with a single destination in mind? Bigelow Destiny I and II are in a ~100km higher orbit than ISS, and different inclination. I would be surprised if Boeing limited the capsule's capabilities so much.
Quote from: thydusk666 on 01/28/2014 02:22 pmAssuming the 401/402 can lift the CST-100 to LEO, how much delta-V/altitude increase would be provided by SRBs, in either 1/2/3/4/5 configuration?No, because there is no need for different delta-V/altitudes
Assuming the 401/402 can lift the CST-100 to LEO, how much delta-V/altitude increase would be provided by SRBs, in either 1/2/3/4/5 configuration?
The ISS is a max inclination for manned station for the foreseeable future.
Quote from: Jim on 01/28/2014 03:57 pmThe ISS is a max inclination for manned station for the foreseeable future.Because there is no need for higher inclinations while it would make it more expensive to reach from lower latitudes, or is there a more fundamental reason?
Of course, those solid boosters must light after the RD-180, so there is already confidence in the liquid portion of the first stage. The RD-180 can be shut down if a SRB failure is detected. Of course, a SRB failure might also take out the Atlas core tank, even with the RD-180 shut down. Either way, the thrust required to get away from an exploding core must be greater than what those Aerojet SRBs can generate. We're not talking Shuttle SRBs here. These things are relatively small. If the CST-100 can get away from a core failure, it should be able to get away from an SRB failure.
Anyways, 400 series Atlas V can only have max of 3 SRM's
Quote from: Jim on 01/28/2014 03:57 pmAnyways, 400 series Atlas V can only have max of 3 SRM'sIs there a technical reason for that? Are the 4xx cores less structurally strong than the 5xx cores or something?I had just assumed that the cores were all the same and ULA just did not bother to offer more than 3SRBs on 4xx cores because they did not anticipate any demand for more, since any payload heavy enough to need more than 3 SRBs would be highly unlikely to fit in a 4m fairing anyway.
Quote from: Comga on 01/28/2014 03:27 pmThank you for posting this, but one bit seems confusing.What is being shown in the center under the heading "Clam Shell CM Design allows easy hardware integration"?Are they saying that the pressure vessel splits at its widest point to allow access before each launch? I would say that is for assembly and not for refurb
Thank you for posting this, but one bit seems confusing.What is being shown in the center under the heading "Clam Shell CM Design allows easy hardware integration"?Are they saying that the pressure vessel splits at its widest point to allow access before each launch?
Are they saying that the pressure vessel splits at its widest point to allow access before each launch? With full atmospheric pressure* that joint is resisting nearlytwo million Newtons (101 kPa * 2.5^2 m^2 * Pi) or a half million pounds of force (14.7 PSI*(2.5 M*40 in/m)^2*Pi). That would indeed be convenient but looks hard to implement. *"Sea level is for sissies"
422 config. as of last June according to Boeing spokesperson: SpaceFlightNow
Quote from: arachnitect on 01/28/2014 06:01 pm422 config. as of last June according to Boeing spokesperson: SpaceFlightNowIf the CST-100 requires an Atlas V 422, does that mean its too heavy for Falcon 9 ?
I’m currently working with a team of talented Boeing and NASA engineers to develop the capability to transport astronauts to the ISS; designing the CST-100 capsule that will launch on top of ULA’s Atlas 422 rocket.
Quote from: InfraNut2 on 01/28/2014 05:34 pmQuote from: Jim on 01/28/2014 03:57 pmAnyways, 400 series Atlas V can only have max of 3 SRM'sIs there a technical reason for that? Are the 4xx cores less structurally strong than the 5xx cores or something?I had just assumed that the cores were all the same and ULA just did not bother to offer more than 3SRBs on 4xx cores because they did not anticipate any demand for more, since any payload heavy enough to need more than 3 SRBs would be highly unlikely to fit in a 4m fairing anyway.too high of acceleration
Quote from: Jim on 01/28/2014 05:44 pmQuote from: InfraNut2 on 01/28/2014 05:34 pmQuote from: Jim on 01/28/2014 03:57 pmAnyways, 400 series Atlas V can only have max of 3 SRM'sIs there a technical reason for that? Are the 4xx cores less structurally strong than the 5xx cores or something?I had just assumed that the cores were all the same and ULA just did not bother to offer more than 3SRBs on 4xx cores because they did not anticipate any demand for more, since any payload heavy enough to need more than 3 SRBs would be highly unlikely to fit in a 4m fairing anyway.too high of accelerationTerse answer as usual. Maybe too terse for me this time.I am not sure I understand.The acceleration problem you mention must be during SRB firing.AFAIK 400-series and 500-series carries the same liquid propellant load in both stages.The total acceleration difference between a 541 (or 551) and a hypothetical 441 (or 451) must then be due to dry mass (and payload) difference. A quick search seem to indicate just something like 3t dry weight difference located in fairing and interstage. The resulting acceleration difference seems much too little to account for the need to limit to 2 less SRBs, if this was just about limiting the acceleration load on the payload.The only reasonable interpretation I can think of is that it is the difference in loads the acceleration put on the centaur that is the limitation. There the acceleration combines unfavorably with increased payload and the fact that the weight of the 4m fairing is carried through the centaur as opposed to being directed around it to the interstage. edit: especially taking into account that the centaur is one of the most dry weight optimized (read: thin-walled) upper stages around...Did I get it right?
Quote from: InfraNut2 on 01/28/2014 07:45 pm(...)The total acceleration difference between a 541 (or 551) and a hypothetical 441 (or 451) must then be due to dry mass (and payload) difference. A quick search seem to indicate just something like 3t dry weight difference located in fairing and interstage. The resulting acceleration difference seems much too little to account for the need to limit to 2 less SRBs, if this was just about limiting the acceleration load on the payload.The only reasonable interpretation I can think of is that it is the difference in loads the acceleration put on the centaur that is the limitation. There the acceleration combines unfavorably with increased payload and the fact that the weight of the 4m fairing is carried through the centaur as opposed to being directed around it to the interstage. edit: especially taking into account that the centaur is one of the most dry weight optimized (read: thin-walled) upper stages around...Did I get it right?My guess is the Centaur in the 400 series have a limit to the stress of lifting the entire payload stack along with aerodynamic forces. Where in the 500 series the payload fairing partially carry some the stress and takes the full aerodynamic forces.
(...)The total acceleration difference between a 541 (or 551) and a hypothetical 441 (or 451) must then be due to dry mass (and payload) difference. A quick search seem to indicate just something like 3t dry weight difference located in fairing and interstage. The resulting acceleration difference seems much too little to account for the need to limit to 2 less SRBs, if this was just about limiting the acceleration load on the payload.The only reasonable interpretation I can think of is that it is the difference in loads the acceleration put on the centaur that is the limitation. There the acceleration combines unfavorably with increased payload and the fact that the weight of the 4m fairing is carried through the centaur as opposed to being directed around it to the interstage. edit: especially taking into account that the centaur is one of the most dry weight optimized (read: thin-walled) upper stages around...Did I get it right?
Quote from: arachnitect on 01/28/2014 06:01 pmQuote from: Comga on 01/28/2014 05:47 pmQuote from: Jim on 01/28/2014 03:38 pmQuote from: Comga on 01/28/2014 03:27 pmThank you for posting this, but one bit seems confusing.What is being shown in the center under the heading "Clam Shell CM Design allows easy hardware integration"?Are they saying that the pressure vessel splits at its widest point to allow access before each launch? I would say that is for assembly and not for refurbAre you saying that they would install the couches and cargo carrying hardware before welding closed the pressure vessel? Looks like mechanical fasteners to me.Should be weld less unless they needed to add some welds that add weight. http://www.parabolicarc.com/2011/03/23/22339/A lot of new technology in the Cs-100 & Orion programs
Quote from: Comga on 01/28/2014 05:47 pmQuote from: Jim on 01/28/2014 03:38 pmQuote from: Comga on 01/28/2014 03:27 pmThank you for posting this, but one bit seems confusing.What is being shown in the center under the heading "Clam Shell CM Design allows easy hardware integration"?Are they saying that the pressure vessel splits at its widest point to allow access before each launch? I would say that is for assembly and not for refurbAre you saying that they would install the couches and cargo carrying hardware before welding closed the pressure vessel? Looks like mechanical fasteners to me.
Quote from: Jim on 01/28/2014 03:38 pmQuote from: Comga on 01/28/2014 03:27 pmThank you for posting this, but one bit seems confusing.What is being shown in the center under the heading "Clam Shell CM Design allows easy hardware integration"?Are they saying that the pressure vessel splits at its widest point to allow access before each launch? I would say that is for assembly and not for refurbAre you saying that they would install the couches and cargo carrying hardware before welding closed the pressure vessel?
What gives you that impression? (that they would open it up)Doing so would be terribly inefficient. There is going to be so much wiring, pipes, and other interfaces that surround and connect the top part of the pressure vessel from the bottom part. Madness.Just see how complex the Orion systems are (a similar design), and they aren't even done installing everything needed for EFT-1.
Quote from: Lars_J on 01/30/2014 04:11 amWhat gives you that impression? (that they would open it up)Doing so would be terribly inefficient. There is going to be so much wiring, pipes, and other interfaces that surround and connect the top part of the pressure vessel from the bottom part. Madness.Just see how complex the Orion systems are (a similar design), and they aren't even done installing everything needed for EFT-1.What makes me think that they will open the entire clamshell for access is Boeing's direct statement in the slide included in this post where they say "Clam Shell CM Design allows easy hardware integration"Frankly, I was amazed to have it shown that Boeing can do this.