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Is there any significance to the fact that both major launches had problems but did not hinder a successful mission? Is that a common occurrence as far as missi

Is there any significance to the fact that both major launches had problems but did not hinder a successful mission? Is that a common occurrence as far as missions go to fail (or have failures) while still gracefully completing?

tharax 14y ago
I remember my statistics lecturer was fond of pointing out that NASA estimated the probability of SOMETHING failing on launch was (1). That is, because of the complexity of the project, there was always something that was missed or broken - although it could have been as simple as a bulb that was backlighting a switch might be blown, or a cupboard might have been restocked incorrectly, or a calculation for external events might be slightly off.
- InclinedPlane 14y ago
  This is the way complex systems work, pretty much. The more systems and sub-systems you need to have running the more likely it is that one will have something wrong with it. And when you add in redundancy and extra capacity you actually increase the chance of something going wrong, you just reduce the chance of it having such a negative effect on the mission.
- neurotech1 14y ago
  They had a shuttle mission where everything was nominal, even the toilet kept working the whole mission. But yeah, space flight is like that. Then again its relatively rare for a jet fighter to consistently return Code 1, no faults. Usually its Code 2 with minor fixes required pretty regularly. Code 3 is an abort.
  - stcredzero 14y ago
    The human body is basically code 2 all the time. It's just that it can fix itself, until you get code 3.
jacquesm 14y ago
I think the 'fail fast' strategy shown here is a pretty good one, freeze as soon as anything is outside normal operating parameters to give you time to decide what to do (I can see Elon Musk standing over a control panel with 'Abort / Retry / Ignore buttons'). The other things that helps is to have many redundant parts. So far they've been able to steer clear of any catastrophic mishaps but given the nature of spaceflight it will be a long time before we can relax on that front. 10's of launches without serious mishap would be quite amazing, so far the statistical base is rather thin. That does nothing to detract from the achievement to date, SpaceX is nothing short of incredible.
gilgoomesh 14y ago
Shuttle mission STS-51 suffered an engine failure but still completed successfully (although at a lower than intended orbit): http://en.wikipedia.org/wiki/STS-51-F http://en.wikipedia.org/wiki/STS-51-F STS-93 also shut down an engine (although not as dramatically): http://en.wikipedia.org/wiki/STS-93 http://en.wikipedia.org/wiki/STS-93 The answer is really: yes, minor issues happen all the time. Something as dramatic as an engine shutdown (as in CRS-1) is rare but not unheard of. With Falcon9/Dragon -- none of these issue have resulted in failure to reach orbit or complete main objectives. If SpaceX weren't under such close scrutiny, we probably wouldn't notice the issues Dragon had on this mission.
InclinedPlane 14y ago
There's pretty much always going to be something that goes wrong, although sometimes it's not as important as other times. To bring in some historical examples. On Apollo 11 there were two major problems. The first was that the chosen launch site was actually filled with enormous spacecraft-wrecking boulders so Armstrong had to fly the LM to a more suitable landing site (and almost ran the thing out of fuel doing it). The second was that a circuit breaker used for arming the ascent engines on the LM got broken during an EVA and the astronauts had to improvise by using a felt-tip pen to activate it. On Apollo 12 the launch vehicle was struck by lightning on ascent and the computers got a bit frazzled, but luckily someone in mission control (John Aaron) knew how to get the system back under control. During Apollo 13's launch severe POGO oscillations in the center engine on the Saturn V first stage almost tore the engine off the rocket (flexing the huge thickness of solid metal that supported the engines by 3 inches) before it was shut-down automatically, and later an Oxygen tank on the CSM exploded during flight. During Apollo 14 it took nearly 2 hours to dock the CSM and the LM (normally this took maybe 10 minutes), there was also a problem with a short-circuit in a switch which forced a software rewrite to be able to land on the moon, and then the landing radar altimeter didn't work and had to be rebooted. I could go on but I think you get my point.

tharax 14y ago

I remember my statistics lecturer was fond of pointing out that NASA estimated the probability of SOMETHING failing on launch was (1). That is, because of the complexity of the project, there was always something that was missed or broken - although it could have been as simple as a bulb that was backlighting a switch might be blown, or a cupboard might have been restocked incorrectly, or a calculation for external events might be slightly off.

InclinedPlane 14y ago
This is the way complex systems work, pretty much. The more systems and sub-systems you need to have running the more likely it is that one will have something wrong with it. And when you add in redundancy and extra capacity you actually increase the chance of something going wrong, you just reduce the chance of it having such a negative effect on the mission.
neurotech1 14y ago
They had a shuttle mission where everything was nominal, even the toilet kept working the whole mission. But yeah, space flight is like that. Then again its relatively rare for a jet fighter to consistently return Code 1, no faults. Usually its Code 2 with minor fixes required pretty regularly. Code 3 is an abort.
- stcredzero 14y ago
  The human body is basically code 2 all the time. It's just that it can fix itself, until you get code 3.

jacquesm 14y ago

I think the 'fail fast' strategy shown here is a pretty good one, freeze as soon as anything is outside normal operating parameters to give you time to decide what to do (I can see Elon Musk standing over a control panel with 'Abort / Retry / Ignore buttons'). The other things that helps is to have many redundant parts. So far they've been able to steer clear of any catastrophic mishaps but given the nature of spaceflight it will be a long time before we can relax on that front. 10's of launches without serious mishap would be quite amazing, so far the statistical base is rather thin. That does nothing to detract from the achievement to date, SpaceX is nothing short of incredible.

gilgoomesh 14y ago

Shuttle mission STS-51 suffered an engine failure but still completed successfully (although at a lower than intended orbit): http://en.wikipedia.org/wiki/STS-51-F http://en.wikipedia.org/wiki/STS-51-F STS-93 also shut down an engine (although not as dramatically): http://en.wikipedia.org/wiki/STS-93 http://en.wikipedia.org/wiki/STS-93 The answer is really: yes, minor issues happen all the time. Something as dramatic as an engine shutdown (as in CRS-1) is rare but not unheard of. With Falcon9/Dragon -- none of these issue have resulted in failure to reach orbit or complete main objectives. If SpaceX weren't under such close scrutiny, we probably wouldn't notice the issues Dragon had on this mission.

InclinedPlane 14y ago

There's pretty much always going to be something that goes wrong, although sometimes it's not as important as other times. To bring in some historical examples. On Apollo 11 there were two major problems. The first was that the chosen launch site was actually filled with enormous spacecraft-wrecking boulders so Armstrong had to fly the LM to a more suitable landing site (and almost ran the thing out of fuel doing it). The second was that a circuit breaker used for arming the ascent engines on the LM got broken during an EVA and the astronauts had to improvise by using a felt-tip pen to activate it. On Apollo 12 the launch vehicle was struck by lightning on ascent and the computers got a bit frazzled, but luckily someone in mission control (John Aaron) knew how to get the system back under control. During Apollo 13's launch severe POGO oscillations in the center engine on the Saturn V first stage almost tore the engine off the rocket (flexing the huge thickness of solid metal that supported the engines by 3 inches) before it was shut-down automatically, and later an Oxygen tank on the CSM exploded during flight. During Apollo 14 it took nearly 2 hours to dock the CSM and the LM (normally this took maybe 10 minutes), there was also a problem with a short-circuit in a switch which forced a software rewrite to be able to land on the moon, and then the landing radar altimeter didn't work and had to be rebooted. I could go on but I think you get my point.