Overly complex, and a solution seeking a market.
...a solution seeking a market.
I mean, I suppose we should just scuttle Chinese cargo ships when the reach the US, because hey, it's overly complex to reuse them.
Quote from: Robotbeat on 03/13/2015 11:37 pmI mean, I suppose we should just scuttle Chinese cargo ships when the reach the US, because hey, it's overly complex to reuse them. As I understand it, there's an abundance of cargo containers in many places in the world as it's cheaper to send the cargo ship back unloaded and no shortage of cargo container makers in China.
(Transferred from CRS-2 thread post)Keep in mind that with a precision launch, Jupiter does not need to do too much more then in/out of the KOS. In theory.And the chief issue with use of the US is the lifetime of the stage - within hours (or less) you want to do the swap and disposal.
Quote from: Bob Shaw on 03/13/2015 11:24 pmOverly complex, and a solution seeking a market.I don't think a tug system like this will noticeably decrease the probability of a successful mission--sure it will decrease it somewhat, but is it enough to ever matter? If the answer is no, then the savings of not tossing the spacecraft bus every time, and require less "wrapper" to be launched each time could actually make it very worthwhile.
NASA needs a capability like this. ISS could have been built this way (or at least finished). Jim has a thread on the topic somewhere on this site. It's essentially a robotic and FAR cheaper version of what Shuttle did with logistics flights to ISS, just with a shorter version of MPLM (although there's no reason in principle they couldn't use a whole MPLM sized container, especially once the tug is placed in orbit).
For reliability concerns, I wonder if it would be worth it to have a second copy of the Jupiter tug module on standby in case of problems with the first?
I'd be curious how they can prove the reliability of the Jupiter tug, if there are rendezvous issues or equipment failures on the tug, you'll need to replace it, as if it fails its not like you can dock it at the ISS for repairs by itself, it might not even be allowed near the ISS if redundancy in equipment is lost, if they guess wrong on how often it'll have to be replaced the cost will go up quite a bit. We have seen various failures of equipment on the ATV during it's time on orbit, and most of that time was docked, this will be far more complex. I like the concept, I'm just not sure how you prove the risk is worth it for this mission.
Quote from: Steam Chaser on 03/14/2015 01:06 amFor reliability concerns, I wonder if it would be worth it to have a second copy of the Jupiter tug module on standby in case of problems with the first?I definitely see redundancy for ISS support. As well if you were using the Jupiter-Electric (or similar) as a tender for a seriously multi planar LEO/MEO satellite constellation you might have a tender on ever other plane but know that for a little penalty of added time it could deliver service/replacement one more plane over, and of course collect duds for deorbitiing.Quote from: WindnWar on 03/14/2015 01:14 amI'd be curious how they can prove the reliability of the Jupiter tug, if there are rendezvous issues or equipment failures on the tug, you'll need to replace it, as if it fails its not like you can dock it at the ISS for repairs by itself, it might not even be allowed near the ISS if redundancy in equipment is lost, if they guess wrong on how often it'll have to be replaced the cost will go up quite a bit. We have seen various failures of equipment on the ATV during it's time on orbit, and most of that time was docked, this will be far more complex. I like the concept, I'm just not sure how you prove the risk is worth it for this mission. The reliability is based on the experience with the individual component hardware systems: the MAVEN bus, the arm, etc. all those systems have already been tested with plenty of on orbit time. The combination may require some engineering analysis, but we are not talking anything more rigorous than mating a different comms system to the Boeing 702 bus.
I never claimed NASA would judge it based on future use.
But why do people think this wouldn't be competitive? Earlier, I showed my math about how I thought it would be competitive, so put up some homework to show why you think otherwise.