Also a possible issue: horizontal versus vertical integration. Falcon 9 (and Dragon, though probably less of an issue) has payloads integrated horizontally, while Atlas V has them integrated vertically.
Quote from: Robotbeat on 09/22/2011 02:09 amAlso a possible issue: horizontal versus vertical integration. Falcon 9 (and Dragon, though probably less of an issue) has payloads integrated horizontally, while Atlas V has them integrated vertically.I guess it just means that you design your capsule to be horizontal and vertically integrated. Given the stresses of launch, the extra care should be making it horizontally integrated. In other words, if it's horizontal, going vertical shouldn't be much of a problem.But yes, from all this problems I guess it means that you have to design your capsule with a lot of flexibility in certain areas. Probably not a problem if you start from zero, but a real meass if you went the route of perfect optimization with a single LV.
Quote from: baldusi on 09/22/2011 03:05 pmQuote from: Robotbeat on 09/22/2011 02:09 amAlso a possible issue: horizontal versus vertical integration. Falcon 9 (and Dragon, though probably less of an issue) has payloads integrated horizontally, while Atlas V has them integrated vertically.I guess it just means that you design your capsule to be horizontal and vertically integrated. Given the stresses of launch, the extra care should be making it horizontally integrated. In other words, if it's horizontal, going vertical shouldn't be much of a problem.But yes, from all this problems I guess it means that you have to design your capsule with a lot of flexibility in certain areas. Probably not a problem if you start from zero, but a real meass if you went the route of perfect optimization with a single LV.Number 2) which I listed as “Acceleration” really should have been “Flight Profile constraints”. Flight profiles and the spacecraft constraints to it are adjusted and analyzed for each flight so this is not really a large delta cost for porting to a new LV since this is done on every flight. Subsequent flights with the same or similar profile become cheaper and easier.
Quote from: oldAtlas_Eguy on 09/21/2011 07:50 pmA manned spacecraft requires “tight” software integration with the LV for information flow from the LV and commands to the LV.Is that true even if the spacecraft doesn't need the capability to control the launch vehicle? I vaguely remember reading that NASA originally had a requirement that Orion should be able to control Ares I but that that requirement was later dropped.
A manned spacecraft requires “tight” software integration with the LV for information flow from the LV and commands to the LV.
If the flexibility to exchange launch vehicles and spacecraft are limited, as they apparently are will Falcon/Dragon and Atlas/CST-100 be positioned for LON, that is when one provider is scheduled will the other pre-position an integrated system in case of extensive launch delay or even mission failure?
Another question - Can the falcon 9/Dragon be launched from Vandenberg and attain the ISS orbit of 51 degrees? If so then assured access to the ISS is maintained by having two separate launch sites and LV's
{snip]The vertical vs horizontal processing issue is one that I missed. This is properly part of mechanical but is a special case that is completely related to the spacecraft. The specialized handling equipment for the spacecraft, cradles etc, to do a vertical vs a horizontal will not be the same and will require additional design and testing (fit checks) to insure it works. There may be other items inside the spacecraft that would be different but not likely since spacecraft have to be built to withstand lateral 2+gs acceleration during flight. Shipping and handling only bracing is designed for the orientation the spacecraft will endure during shipping and handling. New shipping and handling bracing may be required. Fueling of spacecraft may be another item. They maybe only able to be fueled in one orientation, this one may be very difficult to overcome.
Quote from: oldAtlas_Eguy on 09/22/2011 05:29 pm{snip]The vertical vs horizontal processing issue is one that I missed. This is properly part of mechanical but is a special case that is completely related to the spacecraft. The specialized handling equipment for the spacecraft, cradles etc, to do a vertical vs a horizontal will not be the same and will require additional design and testing (fit checks) to insure it works. There may be other items inside the spacecraft that would be different but not likely since spacecraft have to be built to withstand lateral 2+gs acceleration during flight. Shipping and handling only bracing is designed for the orientation the spacecraft will endure during shipping and handling. New shipping and handling bracing may be required. Fueling of spacecraft may be another item. They maybe only able to be fueled in one orientation, this one may be very difficult to overcome.The spacecraft on a Falcon 9 could be fuelled vertically at the launch pad. The supplying fuel tank may need lifting up on a cherry picker.The fuelling needs of the Dragon will need investigating.
Quote from: BrightLight on 09/22/2011 06:32 pmAnother question - Can the falcon 9/Dragon be launched from Vandenberg and attain the ISS orbit of 51 degrees? If so then assured access to the ISS is maintained by having two separate launch sites and LV'sNo. There is not enough propellant for the massive plane change maneuver that would be required. VAFB only makes sense for launching into polar to retrograde orbits.
But the only two domestic launch sites that have access to ISS orbits (without massive inefficiencies) are KSC/CCAFS and Wallops. And unfortunately a natural disaster could wipe out both.VAFB is not going to be practical.
I also have to admit that I do not see the point in LV redundancy for a manned spacecraft. Firstly, it is not like there are empty rockets waiting to fly in case a rocket fails, one would have to be procured. secondly, even if a LV is ready for another mission one cannot just rip off the old payload and put the craft on. So it would probably faster for the LV that failed to have a return to flight than for a switch in LV.
Quote from: Lars_J on 09/23/2011 07:37 pmBut the only two domestic launch sites that have access to ISS orbits (without massive inefficiencies) are KSC/CCAFS and Wallops. And unfortunately a natural disaster could wipe out both.VAFB is not going to be practical.I am sure that if a launch pad is wiped out, insurace or federal assistance will help them recover. I mean, it is not like flooding will wipe out a concrete pedestal and steel buildings, there might be damage.I also have to admit that I do not see the point in LV redundancy for a manned spacecraft. Firstly, it is not like there are empty rockets waiting to fly in case a rocket fails, one would have to be procured. secondly, even if a LV is ready for another mission one cannot just rip off the old payload and put the craft on. So it would probably faster for the LV that failed to have a return to flight than for a switch in LV.
Quote from: Ronsmytheiii on 09/23/2011 08:08 pmQuote from: Lars_J on 09/23/2011 07:37 pmBut the only two domestic launch sites that have access to ISS orbits (without massive inefficiencies) are KSC/CCAFS and Wallops. And unfortunately a natural disaster could wipe out both.VAFB is not going to be practical.I am sure that if a launch pad is wiped out, insurace or federal assistance will help them recover. I mean, it is not like flooding will wipe out a concrete pedestal and steel buildings, there might be damage.I also have to admit that I do not see the point in LV redundancy for a manned spacecraft. Firstly, it is not like there are empty rockets waiting to fly in case a rocket fails, one would have to be procured. secondly, even if a LV is ready for another mission one cannot just rip off the old payload and put the craft on. So it would probably faster for the LV that failed to have a return to flight than for a switch in LV.Actually, if a class 5 Hurricane directly hit CCAFS/KSC, it would be a huge mess. Check New Orleans after Katrina for a reference. Sure, the VAB and the flat concrete pads would survive, but what about the access roads ? I'm sure smaller buildings like the SpaceX HIF would be leveled, along with most of the towers surrounding the pads. Fortunately, they seem to be located in a part of the state that doesn't get directly hit by the tropical storms. It's usually either the southern part of the state (Miami, or farther up the coast in NC).
Here is the problem we have, have had and might continue to have...If CCDEV chooses spacecraft that use the Atlas V (a good LV choice) then as of present, we have one pad to launch our manned missions to LEO/ISS.If CCDEV uses both Falcon 9 and Atlas 5 we can have some level of independence in case a LV has issues but we have no options for bad weather or other unfortunate circumstances that preclude using the Cape. If VAFB is an option then a lot more flexibility is available for guaranteed access to ISS. Unluckily the history of SLC 6 at VAFB gives us some insight (not pretty) into this option.
