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I don't know if this gets said enough, but it bears repeating: we are truly living in a golden age of astronomy. Some incredible things are happening. In my op

I don't know if this gets said enough, but it bears repeating: we are truly living in a golden age of astronomy. Some incredible things are happening. In my opinion, we need to continue to bring the cost to Low Earth Orbit down by any means necessary, including railguns for non-human traffic. Low cost-to-orbit would dramatically speed up dozens of things, exo-planet imaging among them. As much as I love human space travel and robotic exploration, I have to admit that exoplanet research and imaging is really where all the exciting stuff is going to happen. How much longer until we have an image of another Earth? Wonder what a space-based astronomical interferometer about the width of the solar system could image? And that's what? A 10-20B project? Imagine the change in the public's imagination a series of images of the countless other planets in the galaxy would bring.

lutorm 12y ago
I think you're extremely optimistic with that cost estimate. The total cost of the James Webb space telescope will likely end up around $10B... and that's a 6m or something infrared imager in LEO. For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m. That's 18 orders of magnitude higher precision over a proposed 3 orders of magnitude larger baseline. I think it's fair to say the cost of such a mission would be "out of this world", because we have no idea how to build it, and it's not the launch cost to LEO that's the problem.
- skrause 12y ago
  > and that's a 6m or something infrared imager in LEO. James Webb Space Telescope won't be in LEO, they'll fly it to the L2 Lagrange point: http://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbit http://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbi...
  - lutorm 12y ago
    Oh, you're right. My bad.
- mturmon 12y ago
  The hard technology in JWST had to do with the cryocooler, which was needed to cool the infrared detectors to just a few degrees Kelvin. (Of course IR is the whole point of the mission.). The cryocooler was unique in several ways, including sheer size and a complex routing throughout the spacecraft bus. There is no basis to compare the hard technology in JWST to the hard technology in a space interferometer. They are two very different beasts.
- jessriedel 12y ago
  > For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m Could explain what you're saying here better? The LISA satellites will making measurements of changes in the million km distances between each other to an accuracy below 20 picometers.
mturmon 12y ago
This is such a good comment. It's amazing to think that, during our lifetimes, it is likely that we will see an image of another Earth-like planet outside our solar system. Lucky us.

lutorm 12y ago

I think you're extremely optimistic with that cost estimate. The total cost of the James Webb space telescope will likely end up around $10B... and that's a 6m or something infrared imager in LEO. For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m. That's 18 orders of magnitude higher precision over a proposed 3 orders of magnitude larger baseline. I think it's fair to say the cost of such a mission would be "out of this world", because we have no idea how to build it, and it's not the launch cost to LEO that's the problem.

skrause 12y ago
> and that's a 6m or something infrared imager in LEO. James Webb Space Telescope won't be in LEO, they'll fly it to the L2 Lagrange point: http://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbit http://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbi...
- lutorm 12y ago
  Oh, you're right. My bad.
mturmon 12y ago
The hard technology in JWST had to do with the cryocooler, which was needed to cool the infrared detectors to just a few degrees Kelvin. (Of course IR is the whole point of the mission.). The cryocooler was unique in several ways, including sheer size and a complex routing throughout the spacecraft bus. There is no basis to compare the hard technology in JWST to the hard technology in a space interferometer. They are two very different beasts.
jessriedel 12y ago
> For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m Could explain what you're saying here better? The LISA satellites will making measurements of changes in the million km distances between each other to an accuracy below 20 picometers.

mturmon 12y ago

This is such a good comment. It's amazing to think that, during our lifetimes, it is likely that we will see an image of another Earth-like planet outside our solar system. Lucky us.