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SLS for launching large space telescopes (was SLS alternatives)
On Oct 30, 6:37*pm, Brian Thorn wrote:
On Tue, 30 Oct 2012 14:55:56 -0700 (PDT), bob haller wrote: http://www.space.com/18275-nasa-sls-...-missions.html So NASA is dreaming about SLS payloads, too... Brian Very exciting astronomy missions become possible also with the SLS: SLS Useful for Science Missions, Too, STScI Director Tells House Panel. Marcia S. Smith Posted: 17-Sep-2012 Quote:
Telescopes with mirrors 15 to 25 meters across might be too ambitious since we don't have those even for ground scopes yet. But we can certainly imagine 10 meter telescopes. I looked up some costs of the largest ground scopes and was surprised by how low cost they were compared to typical space missions. The Keck 1 and Keck 2, which are each 10 meter scopes, cost in the range of $100 million each in 1993 dollars. And the Large Binocular Telescope(LBT) whose twin 8.4 meter mirrors give it the collecting power of a 11.9 meter scope cost only $120 million in 2005 dollars. This compared to the likely billion dollar launch costs of the SLS. There would be additional costs at making these scopes space qualified, but on the other hand you don't have the large costs of constructing the buildings to house such large telescopes on the ground. The LBT case is especially interesting in that the twin mirrors if they could be used together to create a single image they would have the resolution of a 22.8 meter telescope. This would put it in the range able to detect life on extrasolar planets. According to the Wikipedia page on the LBT, this image synthesis mode has been tested but has not been part of the regular use. Likely cost has been a limiting factor. However, the National Reconnaissance Office has an ever increasing need for better and better imaging resolution from space. Reportedly they already have launched billion dollar satellites. Then they could be a source for the funding to perfect the image combining methods. Bob Clark |
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SLS for launching large space telescopes (was SLS alternatives)
On Nov 1, 7:38*am, Jeff Findley wrote:
In article 5f61fc60-0036-4809-8d0d-ac4e0890a79e@ 10g2000vbu.googlegroups.com, says... On Oct 30, 6:37 pm, Brian Thorn wrote: On Tue, 30 Oct 2012 14:55:56 -0700 (PDT), bob haller wrote: http://www.space.com/18275-nasa-sls-...-missions.html So NASA is dreaming about SLS payloads, too... Brian *Very exciting astronomy missions become possible also with the SLS: SLS Useful for Science Missions, Too, STScI Director Tells House Panel. Marcia S. Smith Posted: 17-Sep-2012 Quote:
*Telescopes with mirrors 15 to 25 meters across might be too ambitious since we don't have those even for ground scopes yet. But we can certainly imagine 10 meter telescopes. I looked up some costs of the largest ground scopes and was surprised by how low cost they were compared to typical space missions. The Keck 1 and Keck 2, which are each 10 meter scopes, cost in the range of $100 million each in 1993 dollars. And the Large Binocular Telescope(LBT) whose twin 8.4 meter mirrors give it the collecting power of a 11.9 meter scope cost only $120 million in 2005 dollars. This compared to the likely billion dollar launch costs of the SLS. *There would be additional costs at making these scopes space qualified, but on the other hand you don't have the large costs of constructing the buildings to house such large telescopes on the ground. *The LBT case is especially interesting in that the twin mirrors if they could be used together to create a single image they would have the resolution of a 22.8 meter telescope. This would put it in the range able to detect life on extrasolar planets. According to the Wikipedia page on the LBT, this image synthesis mode has been tested but has not been part of the regular use. Likely cost has been a limiting factor. However, the National Reconnaissance Office has an ever increasing need for better and better imaging resolution from space. Reportedly they already have launched billion dollar satellites. Then they could be a source for the funding to perfect the image combining methods. Your data just proves that terrestrial based telescopes are far cheaper to build than space based. *When you include development costs, operational costs, and the cost of servicing missions for Hubble, it becomes a very expensive program indeed. *Wikipedia states that as of 2010, total Hubble costs are were about US $10 billion. Add another ten billion for the all-inclusive secondary terrestrial market, and then put on the table anything that has directly benefited humanity. $20 billion invested for what exactly? Assuming identical costs for an SLS launched telescope, even though it could be far larger, or placed in an orbit further from earth, I'm not sure Congress would be willing to cough up that kind of money. *James Webb Space Telescope costs are reportedly currently estimated to be somewhere around $6.8 billion, and it's still many years away from being launched (currently scheduled for 2018, but could slip). NASA is establishing quite a track record for large space telescopes whose schedule routinely slips and whose budget routinely balloons into the multi-billion dollar range. Still, even if an SLS launched space telescope is approved, I would think it very unlikely that NASA would get funding to build more than one copy. *This will do little to boost SLS flight rate on a year to year basis. *The "build it and they will come" philosophy doesn't necessarily mean that "they will come" in large quantities. Jeff -- "the perennial claim that hypersonic airbreathing propulsion would magically make space launch cheaper is nonsense -- LOX is much cheaper than advanced airbreathing engines, and so are the tanks to put it in and the extra thrust to carry it." - Henry Spencer Putting all of astronomy accomplishments (including Hubble) on the table, has fed and cared for how many regular people in need of food, housing, medical care or basic freedoms? |
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