It's just my opinion but I think a manned craft landing safely is the most important requirement.
Quote from: BrightLight on 07/24/2018 03:33 pmIt's just my opinion but I think a manned craft landing safely is the most important requirement.More important than all the other safety-critical parts of the mission?And remember that the only crewed vehicle that did not make it in one piece had wings. So your assumptions are statistically wrong.Also looking at the CCP assessment, if I remember correctly, the hardest risk to control/mitigate were micrometeorites. Adding wings and a plane shape would not help there in any way.Going back to requirements, you are also wrong. The main requirement is to ferry people to and from space.If landing safety is the most important requirement, you don't even get off ground.And I can assure you that it will not be the most important requirement on a Mars mission. Any Mars mission will have a large failure risk.Space has a moderate risk, let's accept it. Your view is NASA's view since Challenger, which got us nowhere in the past 30 years.
F9 doesn't seem to be bothered with that. And air traffic control says "thanks!".
Quote from: IRobot on 07/24/2018 08:59 amF9 doesn't seem to be bothered with that. And air traffic control says "thanks!".Of course not, because if there's any issues in the launch window it stays sitting in the same place, it doesn't continue to drift along at 17,500 mph.Reentry windows can be trickier because if you have to miss the first pass you need a bit of crossrange to make up the difference.
Quote from: GWH on 07/24/2018 12:52 amRunways are a much better alternative to landing in the ocean or tossing your heatshield down onto the desert surface IMO.If you focus only on the final meters of your long trip, yes, you are right. And that's the problem of driving design from a single requirement. This space plane fascination makes people wanting to justify the plane-shape by all means, like making the landing the single most important requirement.
Runways are a much better alternative to landing in the ocean or tossing your heatshield down onto the desert surface IMO.
Not true, crew dream chaser has everything contained in the outer moldline. Starliner makes use of a disposable service module. Even with the disposable module on cargo dream chaser they have stated they expect very low recurring costs on the vehicle.
Quote from: GWH on 07/25/2018 06:53 pmNot true, crew dream chaser has everything contained in the outer moldline. Starliner makes use of a disposable service module. Even with the disposable module on cargo dream chaser they have stated they expect very low recurring costs on the vehicle.I thought DC also had a disposable service module?
Quote from: BrightLight on 07/24/2018 03:33 pmIt's just my opinion but I think a manned craft landing safely is the most important requirement.More important than all the other safety-critical parts of the mission?And remember that the only crewed vehicle that did not make it in one piece had wings.
Quote from: IRobot on 07/24/2018 08:30 pmQuote from: BrightLight on 07/24/2018 03:33 pmIt's just my opinion but I think a manned craft landing safely is the most important requirement.More important than all the other safety-critical parts of the mission?And remember that the only crewed vehicle that did not make it in one piece had wings. Neither shuttle accident was due to failure of the spacecraft. One was SRB and other was damage from insulation falling off main tank. Its like saying an aircraft design is failure due crash from a bird strike.
Quote from: TrevorMonty on 07/28/2018 06:03 pmQuote from: IRobot on 07/24/2018 08:30 pmQuote from: BrightLight on 07/24/2018 03:33 pmIt's just my opinion but I think a manned craft landing safely is the most important requirement.More important than all the other safety-critical parts of the mission?And remember that the only crewed vehicle that did not make it in one piece had wings. Neither shuttle accident was due to failure of the spacecraft. One was SRB and other was damage from insulation falling off main tank. Its like saying an aircraft design is failure due crash from a bird strike.no...in both cases the spacecraft system failed...as did teh management a bird strike is "random chance" what happened with Challenger and Columbia had little random about it
The debate wasn't about shuttle system as a whole but wing vehicle vs capsule on reentry. The shuttle vehicle didn't fail because of its design. The complete launch system that shuttle used to get to space did fail twice.
Quote from: TrevorMonty on 07/29/2018 10:30 amThe debate wasn't about shuttle system as a whole but wing vehicle vs capsule on reentry. The shuttle vehicle didn't fail because of its design. The complete launch system that shuttle used to get to space did fail twice.Agreed the orbiter part of the system was very reliable so long as there were no anomalies during launch.The aircraft style landing mode is so far in practice has been the safest way to bring back a vehicle.When you think about how many accidents have happened the method used by Soyuz is actually fairly dangerous in comparison.
Quote from: TrevorMonty on 07/29/2018 10:30 amThe debate wasn't about shuttle system as a whole but wing vehicle vs capsule on reentry. The shuttle vehicle didn't fail because of its design. The complete launch system that shuttle used to get to space did fail twice.Agreed the orbiter part of the system was very reliable so long as there were no anomalies during launch.The aircraft style landing mode is so far in practice has been the safest way to bring back a vehicle.
You need to add the qualifier "no anomalies during launch", but that's not really a fair way of judging it since the anomaly on launch was something that happened only because it was a winged design.Winged designs cause all sorts of other design decisions. With Columbia, one of the design decisions caused by going with a winged design caused the loss of Columbia. It's not fair to absolve the winged design of that failure because it's a direct result of the winged design. A capsule would not have failed this way.Winged designs have a worse rate of killing people than capsules. Maybe future winged designs will be safer, but that's the nature of looking at historical results. The historical results, so far, say that winged designs are less safe.Other winged designs in the future may not have the same failures that have been seen in the past. But the fundamental underlying cause is still there: winged designs are more complex, and that added complexity causes trade-offs throughout the system, trade-offs that can lead to loss of the crew.
The main problem was not the wings, it was the side mounting. A capsule astride a Shuttle-C would have also been subject to debris strikes. This is not to say that wings or lifting bodies don't present problems, but they are resolvable. The death rate aboard winged vehicles is higher simply because STS flew more people.
Quote from: Patchouli on 07/30/2018 12:48 amQuote from: TrevorMonty on 07/29/2018 10:30 amThe debate wasn't about shuttle system as a whole but wing vehicle vs capsule on reentry. The shuttle vehicle didn't fail because of its design. The complete launch system that shuttle used to get to space did fail twice.Agreed the orbiter part of the system was very reliable so long as there were no anomalies during launch.The aircraft style landing mode is so far in practice has been the safest way to bring back a vehicle.You need to add the qualifier "no anomalies during launch", but that's not really a fair way of judging it since the anomaly on launch was something that happened only because it was a winged design.Winged designs cause all sorts of other design decisions. With Columbia, one of the design decisions caused by going with a winged design caused the loss of Columbia. It's not fair to absolve the winged design of that failure because it's a direct result of the winged design. A capsule would not have failed this way.Winged designs have a worse rate of killing people than capsules. Maybe future winged designs will be safer, but that's the nature of looking at historical results. The historical results, so far, say that winged designs are less safe.Other winged designs in the future may not have the same failures that have been seen in the past. But the fundamental underlying cause is still there: winged designs are more complex, and that added complexity causes trade-offs throughout the system, trade-offs that can lead to loss of the crew.