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It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.
That's what I never understood. Why implement by design a potential single point of failure? As yokem55 wrote, CRS2 for example, had the time margin and reserves to fix delayed firing. Soyuz and Progress for example had similar things like CRS2 happen and could manage it.
It is also is a guarantee of return due to a failure of the propulsion system.
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It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.
That's what I never understood. Why implement by design a potential single point of failure? As yokem55 wrote, CRS2 for example, had the time margin and reserves to fix delayed firing. Soyuz and Progress for example had similar things like CRS2 happen and could manage it.
It is also is a guarantee of return due to a failure of the propulsion system.
The propulsion system is designed such that it is multiple redundant on Starliner. A single failure does not render the entire propulsion system inoperative. To render Starliner completely unable to de-orbit itself, requires at least THREE independent failures.
It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.
It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.This seems like a not-so-great way to get rid of the excess fuel. How about launching into slightly different plane, then using the excess to correct? Launch into a higher than needed orbit, then use the excess to lower it? Launch into the orbit you want, then do half a burn forward, followed by half a burn back? Seems like there are lots of ways to use up fuel without putting yourself in a time crunch.
While I believe there is something to the MET timer causing an issue, I don't understand how a mission timer could be sole reason for the failure to properly insert.
Are you telling me the entire Starliner autopilot just operates on that timer, and once it was clear that no insertion was happening, its RCS thrusters continued to operate as though it was inserting? It doesn't take into account attitude, velocity etc.... and you know, sensors that verify the engines are firing. The explanation doesn't make sense IMO based on what we know right now.
Also, the fact there was a failure to communicate for 8 minutes seems excessive. I get temporary drop outs due to coverage, but 8 minutes? Seems like a poor design to do your orbital insertion maneuver where there is no communication link to NASA??? We are not on the far side of the moon here.
I know it's tempting to point to the decision to have Atlas/Centaur deliver Starliner on a sub-orbital trajectory as the problem. But it's not the problem. As Jim points out there are other trades that would have to be made if they changed that decision. And there are other parts of the timeline where the failure we saw today might have impacted the launch differently completely absent that choice.
They just need to fix the issue, they don't need to change their mind about the sub-orbital insertion.
It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.
But you get free return when launching in a lower one.
[...]
It was reported by ULA just a few days ago that N22 Atlas V is perfectly capable of delivering Starliner all the way into orbit. The reason it delivers Starliner to suborbital is because Boeing requested it. Reason: burn of excess (and no longer needed) abort propellant by doing the final orbital insertion burn. That makes sure Starliner doesn't carry around an excessive amount of fuel on ISS approach and docking, and during post-undocking flight.
That's what I never understood. Why implement by design a potential single point of failure? As yokem55 wrote, CRS2 for example, had the time margin and reserves to fix delayed firing. Soyuz and Progress for example had similar things like CRS2 happen and could manage it.
It is also is a guarantee of return due to a failure of the propulsion system.
The propulsion system is designed such that it is multiple redundant on Starliner. A single failure does not render the entire propulsion system inoperative. To render Starliner completely unable to de-orbit itself, requires at least THREE independent failures.
Doesn't change what I said
This seems like a not-so-great way to get rid of the excess fuel. How about launching into slightly different plane, then using the excess to correct? Launch into a higher than needed orbit, then use the excess to lower it? Launch into the orbit you want, then do half a burn forward, followed by half a burn back? Seems like there are lots of ways to use up fuel without putting yourself in a time crunch.But you get free return when launching in a lower one.
This seems like a not-so-great way to get rid of the excess fuel. How about launching into slightly different plane, then using the excess to correct? Launch into a higher than needed orbit, then use the excess to lower it? Launch into the orbit you want, then do half a burn forward, followed by half a burn back? Seems like there are lots of ways to use up fuel without putting yourself in a time crunch.But you get free return when launching in a lower one.
...which no other crewed spacecraft needs, apparently? Shuttle did it, but that was also due to ET disposal concerns.
If you are launching into space and you are THAT concerned that basic propulsion won’t work (I mean this is the abort system!) to the point where you insist on a “free return”, then perhaps you shouldn’t be launching in the first place until your confidence is higher?
But you get free return when launching in a lower one.The most valuable resource during a contingency is time.
If the spacecraft is unhealthy, a fast forced return is a recipe for LOC.
Being stranded in orbit is a very remote second risk in comparison.
This seems like a not-so-great way to get rid of the excess fuel. How about launching into slightly different plane, then using the excess to correct? Launch into a higher than needed orbit, then use the excess to lower it? Launch into the orbit you want, then do half a burn forward, followed by half a burn back? Seems like there are lots of ways to use up fuel without putting yourself in a time crunch.But you get free return when launching in a lower one.
...which no other crewed spacecraft needs, apparently? Shuttle did it, but that was also due to ET disposal concerns.
If you are launching into space and you are THAT concerned that basic propulsion won’t work (I mean this is the abort system!) to the point where you insist on a “free return”, then perhaps you shouldn’t be launching in the first place until your confidence is higher?
The same argument could be made about launch escape systems, airbags, requirement to wear seat-belts... I'm considering it invalid.
Besides that, the suborbital trajectory does not only protect against propulsion failure specifically, it protects against any failure that would render the spacecraft unable to make its de-orbit burn in time to safe the crew in case of an unknown, catastrophic fault.
This includes, but is not limited to failures of the propulsion system in the narrow sense.
Systems that would make immediate reentry necessary but prevent a "regular" deorbit burn include:
- Main power system (Without power you probably can't do much of anything)
- Avionics failure (Even with manual thruster override, you need some avionic systems and instruments to allow humans to reenter - starting with guidance+nav computers and related sensors. If inertial sensors and artificial horizon is down, steering the correct attitude for reentry is going to be tough)
- Tank pressurization failure (with no pressurant for the propellants, there's no thrust)
- Propellant system failure (major leaks/tank ruptures)
- Thruster failure ( Starliner has thrusters in an off-axis configuration. It's properly sufficient to lose 2 out of 4 to cripple Starliner, since attitude control cannot overcome the off-axis thrust )
- Communication failure (Something else happened, so that the craft needs to return but can't be commanded to do so due to comm failure)
A good argument can be made for a free-return within a shorter time span than the capsule remains survivable for the crew even with critical damage
Assume something exploded, hull is depressurized, power is down, the crew is protected by their pressure suits but otherwise incapacitated.
It's a worse case scenario, but if the capsule has failsafes to shed its service module and orient correctly and survive ballistic reentry (which by the way was the case with Soyuz several times) and has redundant backup triggers for the chutes, this is exactly whats needed to give the people on board a chance. There's also not really any alternative. (Unless you have a rocket ready to send a 2nd spacecraft up and assist)
Someone did the decision to design the craft with a fail safe for that kind of contingency in the mission profile. It's a design decision which everyone hopes will proof unnecessary over time. But questioning that now, just because something went wrong on ascent would be totally wrong.
After all, the capsule did enter orbit despite all issues. Yes, it wasted too much fuel on attitude control, that's why it can't achieve all mission objectives anymore (aka can't reach ISS) but the mission is far from a failure. The chain of events known so far simply does not hold any justification for questioning Boeings decision to deploy suborbital.
It's different from SpaceX ascent profile. SpaceX does things differently. SpaceX seems to trusts automation more than Boeing as well. And they have significant experience sending capsules up and bringing them back down safely.
At the same time I would not go as far and critizise SpaceX decision to put their capsule into a proper orbit, from where it has to do a "real" deorbit burn. SpaceX has a different architecture, where the launch vehicle and capsule are closer integrated than Boeing can, who uses a third party launcher and deliberately made Starliner "launch vehicle agnostic"
If anything goes wrong with the capsule on ascent - SpaceX can totally argue, they can stop the Falcon9 2nd stage burn early and abort the launch on any survivablee suborbital trajectory. The launch vehicle operators and the capsule operators sit in the same control room, the avionics run on the same hardware. Launcher and Capsule are one integrated system. The contingency to remain suborbital in case of most types of troubles can be assured by the launch vehicle.
Boeing does not have that luxury, so I can fully see the desire to control the final orbital insertion and not rely on the launch vehicle - both for safety and for precision. (Not that Atlas/Centaur has any lack thereof, but Starliner is envisioned to fly also on new rockets that haven't even flown once yet)
While I believe there is something to the MET timer causing an issue, I don't understand how a mission timer could be sole reason for the failure to properly insert.
Are you telling me the entire Starliner autopilot just operates on that timer, and once it was clear that no insertion was happening, its RCS thrusters continued to operate as though it was inserting? It doesn't take into account attitude, velocity etc.... and you know, sensors that verify the engines are firing. The explanation doesn't make sense IMO based on what we know right now.
Yep, this has been bugging me too, since we know that Orion and Dragon have triple-redundant computer systems that can withstand being blasted by radiation and still recover.
Here we have an apparently nominal flight where the entire spacecraft loses track of what time it is? Doesn't the software check to see if all clocks are in sync before each mission objective is executed?QuoteAlso, the fact there was a failure to communicate for 8 minutes seems excessive. I get temporary drop outs due to coverage, but 8 minutes? Seems like a poor design to do your orbital insertion maneuver where there is no communication link to NASA??? We are not on the far side of the moon here.
Yep, the other thing bugging me. Why is there a need to communicate with Earth at all? We have fairly decent self-driving cars here on Earth, so why can't they have fully autonomous flight control software that would monitor and manage the flight?
And I'm not arguing against being able to take manual control, just that we are technologically advanced enough to have computer systems that can understand when something is going wrong, and to reassess whether the mission should proceed or that input from humans is required. Obviously there is no overall system monitoring fuel consumption vs mission objectives, otherwise this wouldn't have happened.
To summarize, the hardware worked but the software failed. This is a pattern we've seen before with Boeing, and they need to understand that they may have an institutional problem.
My $0.02
If you are launching into space and you are THAT concerned that basic propulsion won’t work (I mean this is the abort system!) to the point where you insist on a “free return”, then perhaps you shouldn’t be launching in the first place until your confidence is higher?
The same argument could be made about launch escape systems, airbags, requirement to wear seat-belts... I'm considering it invalid.
Besides that, the suborbital trajectory does not only protect against propulsion failure specifically, it protects against any failure that would render the spacecraft unable to make its de-orbit burn in time to safe the crew in case of an unknown, catastrophic fault.
This includes, but is not limited to failures of the propulsion system in the narrow sense.
Systems that would make immediate reentry necessary but prevent a "regular" deorbit burn include:
- Main power system (Without power you probably can't do much of anything)
- Avionics failure (Even with manual thruster override, you need some avionic systems and instruments to allow humans to reenter - starting with guidance+nav computers and related sensors. If inertial sensors and artificial horizon is down, steering the correct attitude for reentry is going to be tough)
- Tank pressurization failure (with no pressurant for the propellants, there's no thrust)
- Propellant system failure (major leaks/tank ruptures)
- Thruster failure ( Starliner has thrusters in an off-axis configuration. It's properly sufficient to lose 2 out of 4 to cripple Starliner, since attitude control cannot overcome the off-axis thrust )
- Communication failure (Something else happened, so that the craft needs to return but can't be commanded to do so due to comm failure)
A good argument can be made for a free-return within a shorter time span than the capsule remains survivable for the crew even with critical damage
Assume something exploded, hull is depressurized, power is down, the crew is protected by their pressure suits but otherwise incapacitated.
It's a worse case scenario, but if the capsule has failsafes to shed its service module and orient correctly and survive ballistic reentry (which by the way was the case with Soyuz several times) and has redundant backup triggers for the chutes, this is exactly whats needed to give the people on board a chance. There's also not really any alternative. (Unless you have a rocket ready to send a 2nd spacecraft up and assist)
Someone did the decision to design the craft with a fail safe for that kind of contingency in the mission profile. It's a design decision which everyone hopes will proof unnecessary over time. But questioning that now, just because something went wrong on ascent would be totally wrong.
But you get free return when launching in a lower one.The most valuable resource during a contingency is time.
If the spacecraft is unhealthy, a fast forced return is a recipe for LOC.
Being stranded in orbit is a very remote second risk in comparison.
Unsupported claims
The spacecraft can support uncontrolled entry. It is dynamical stable. So fast return is not an ingredient in the recipe for LOC.
Therefore, stranded in orbit is a much higher risk by magnitudes
But you get free return when launching in a lower one.The most valuable resource during a contingency is time.
If the spacecraft is unhealthy, a fast forced return is a recipe for LOC.
Being stranded in orbit is a very remote second risk in comparison.
Unsupported claims
The spacecraft can support uncontrolled entry. It is dynamical stable. So fast return is not an ingredient in the recipe for LOC.
Therefore, stranded in orbit is a much higher risk by magnitudesA HEALTHY spacecraft can.
One that's doing weird s**t and you don't know why - I'd rather have an opportunity to figure out what's going on before being forced into EDL.
Is suborbital insertion the default for all missions or was it special for this one?