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0 pointsrtkwe9y ago0 comments

> Consider, fixing Hubble was a big thing, but we could have sent 3 of them up for less money.

Not even close. It cost ~900M for the repair mission and the cost to build Hubble was ~2.5B.

>No, the ITER robot needs to deal with heavy loads, micro G means even small forces add up. Don't forget without people they could send 3x the science payloads. So, scrapping things and trying again really is viable.

Less forces only means that the motors can be weaker but it doesn't lower the overall complexity required, you still have to have X degrees of freedom to get an arm that can barely replace a human in limited circumstances. Telerobotics just isn't there or cheap enough to make it make sense.

> As to micro G, we could send a mars mission with simulated gravity. Which is something we really should be testing instead of simply yet another long stay in micro G.

We /could/ do simulated gravity but there's a lot of engineering issues with that that make it a Gen 2+ solution for a Mars trip or for a more long term solution like a Mars cycler. Just the size required for a spinning torus to be comfortable and provide enough gravity to be worth it would make it much larger than the ISS [0] [1]. There are other problems like dealing with communication equipment and docking which would want a stationary center which brings in more complexity with the seals between the stationary section and the ring. There's other options like a bolas but they're also pretty complex. Until then we'll need to deal with space travel as it comes to us which is without gravity. In short to test and build them we'll need either a large decrease in launch costs or a truly massive pile of money.

[0] http://www.spacefuture.com/archive/artificial_gravity_and_th...

[1] http://space.stackexchange.com/questions/1308/why-are-there-...

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Retric9y ago

> Not even close. It cost ~900M for the repair mission and the cost to build Hubble was ~2.5B.

There where 6 Hubble servicing missions. "this last Hubble servicing mission is expected to cost about $1.1 billion" http://www.space.com/6648-hubble-faq-space-telescope-repair-...

Further, 15 years is considered a relatively short lifetime for a satellite, so Hubble 2 and 3 could have easily had a longer total lifespan if they had kept them in a higher orbit because there was no need for servicing. Instead "the space telescope was designed to typically go only three years between overhauls."

AKA, they designed it to need 'fixing'.

rtkweOP9y ago

26 years (it's still going after all because of the repairs done by shuttle missions) is a long life for a space telescope and particularly for one during it's time. Before Hubble most telescopes were only around for a handful of years before being shutdown.

There's a big difference between designing to fail and designing to be repairable. Even if it's possible it could have been cheaper to launch multiples but it's unlikely NASA could have gotten the funding to start making Hubble 2 in time for it to replace Hubble.

Retric9y ago

Granted, nobody died, NASA got great press from the Hubble, and it made the shuttle seem useful. And sure funding would have been harder due to less feel good missions, but easier from 1+ billion lower costs. So, I am not going to call it the dumbest thing NASA has done.

However, as to lifespan, from April 24, 1990 to Dec, 1993 the Hubble was significantly 'impaired'. If the next two averaged 10-12 years and the original continued to be useful for a few years that's well past break even. Especially considering the Hubble always suffered from a defective mirror even after the first servicing mission help that's not unreasonable.

PS: By designing to fail I don't mean they intentionally made it worse, just assuming servicing caused a wide range of problems. Sure, NASA did learn something from going though this exercise. But the highly political nature of the organization limits such benefits.

Edit: Yes, many telescopes had a very short lifespan though that was often by design. https://en.wikipedia.org/wiki/Rossi_X-ray_Timing_Explorer Mission duration 16 years, 6 days. https://en.wikipedia.org/wiki/International_Ultraviolet_Expl... 18 years. https://en.wikipedia.org/wiki/MOST_(satellite) 13+ (still up) https://en.wikipedia.org/wiki/Spitzer_Space_Telescope 13 years and counting. https://en.wikipedia.org/wiki/PAMELA_detector 10 years and counting. https://en.wikipedia.org/wiki/Solar_Anomalous_and_Magnetosph... 11 years 11 months. There are also quite a few up which may or may not last a long time.

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Retric9y ago

> Not even close. It cost ~900M for the repair mission and the cost to build Hubble was ~2.5B.

There where 6 Hubble servicing missions. "this last Hubble servicing mission is expected to cost about $1.1 billion" http://www.space.com/6648-hubble-faq-space-telescope-repair-...

AKA, they designed it to need 'fixing'.

rtkweOP9y ago

Retric9y ago

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