3 ms·

Than why not launch them? I mean, isn't HST oversubscribed and wouldn't having 3x observing time a net boon for the science community?

adventured 9y ago
I doubt there's any way to easily estimate the cost, but the two HST-superior telescopes NASA was given by the NRO, need to be made science-ready. There are no instruments on them. Say for example that the cost would be $500m to $1 billion over several years to get them ready, then another $1 or $2 billion over ten years to operate them both. If you're NASA and you have $23 billion to spend per year average over that time, do you invest into the two telescopes and divert resources, or stick with HST until its end and focus on Webb. Obviously if the US Government were behaving more rational, NASA would be given the resources to prep these telescopes and launch them. They're exceptional gear going to waste, surely we could task something interesting for them.
macintux 9y ago
I was unaware we had more, so this is pure speculation, but I would imagine that having continuous coverage is considered critical, so if we launch another one and it experiences a failure soon after the current Hubble fails, we’ve lost that margin of error. Fundamentally it’s much safer sitting in storage.
- sjm-lbm 9y ago
  How would having the backup in orbit reduce the amount of coverage that an HST-type device could provide? It seems like having another telescope in orbit could basically be a "hot-spare" for the highest priority tasks while continuing to do lower priory work in the mean time.
  - macintux 9y ago
    Because it's safer on the ground. If you put everything you have up in the sky, and they all fail for various reasons (solar storm, collision, wear & tear) then you're screwed. Regardless, per another comment it sounds more like a budget problem, so my speculation was crap anyway.
    - sjm-lbm 9y ago
      Yeah, I guess I understand that, it just seems like most things that aren't a design failure are unlikely to affect more than one orbiting telescope. In other words, to return to your example, it seems unlikely to me that a collision would happen to more than on telescope ever, let alone in a time window too tight for a third (or fourth, etc) telescope to be built and launched. (and, anyway, it looks like you are right: this is all budgetary anyway, so whatever)
- Rebelgecko 9y ago
  Storing a satellite in space is significantly cheaper and not that much riskier than storing it on the ground
  - zaarn 9y ago
    You can't repair satellites beyond LEO very easily though, so if your spares fail in spaces, that's it. If your spare gets damaged in storage on earth, you send the electrician over with a car.
    - Rebelgecko 9y ago
      Satellites don't break significantly faster in orbit than in storage. Storage can easily cost $5 million a year, but on top of cost savings there's other benefits to sending your payload up early (assuming you've budgeted for a bit more battery wear, fuel consumption, etc.) The most dangerous time for a satellite is by far the first couple months. This is when most design and QC failures become apparent. If you launch before you need your satellite, you can do your on-orbit checkouts and not be in a rush to deal with any anomalies. When your preexisting operational satellite dies, you can have one ready to go immediately instead of needing to beg borrow or bribe your way to a better position in a launch provider's manifest.

adventured 9y ago

I doubt there's any way to easily estimate the cost, but the two HST-superior telescopes NASA was given by the NRO, need to be made science-ready. There are no instruments on them. Say for example that the cost would be $500m to $1 billion over several years to get them ready, then another $1 or $2 billion over ten years to operate them both. If you're NASA and you have $23 billion to spend per year average over that time, do you invest into the two telescopes and divert resources, or stick with HST until its end and focus on Webb. Obviously if the US Government were behaving more rational, NASA would be given the resources to prep these telescopes and launch them. They're exceptional gear going to waste, surely we could task something interesting for them.

macintux 9y ago

I was unaware we had more, so this is pure speculation, but I would imagine that having continuous coverage is considered critical, so if we launch another one and it experiences a failure soon after the current Hubble fails, we’ve lost that margin of error. Fundamentally it’s much safer sitting in storage.

sjm-lbm 9y ago
How would having the backup in orbit reduce the amount of coverage that an HST-type device could provide? It seems like having another telescope in orbit could basically be a "hot-spare" for the highest priority tasks while continuing to do lower priory work in the mean time.
- macintux 9y ago
  Because it's safer on the ground. If you put everything you have up in the sky, and they all fail for various reasons (solar storm, collision, wear & tear) then you're screwed. Regardless, per another comment it sounds more like a budget problem, so my speculation was crap anyway.
  - sjm-lbm 9y ago
    Yeah, I guess I understand that, it just seems like most things that aren't a design failure are unlikely to affect more than one orbiting telescope. In other words, to return to your example, it seems unlikely to me that a collision would happen to more than on telescope ever, let alone in a time window too tight for a third (or fourth, etc) telescope to be built and launched. (and, anyway, it looks like you are right: this is all budgetary anyway, so whatever)
Rebelgecko 9y ago
Storing a satellite in space is significantly cheaper and not that much riskier than storing it on the ground
- zaarn 9y ago
  You can't repair satellites beyond LEO very easily though, so if your spares fail in spaces, that's it. If your spare gets damaged in storage on earth, you send the electrician over with a car.
  - Rebelgecko 9y ago
    Satellites don't break significantly faster in orbit than in storage. Storage can easily cost $5 million a year, but on top of cost savings there's other benefits to sending your payload up early (assuming you've budgeted for a bit more battery wear, fuel consumption, etc.) The most dangerous time for a satellite is by far the first couple months. This is when most design and QC failures become apparent. If you launch before you need your satellite, you can do your on-orbit checkouts and not be in a rush to deal with any anomalies. When your preexisting operational satellite dies, you can have one ready to go immediately instead of needing to beg borrow or bribe your way to a better position in a launch provider's manifest.