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Friday, June 8, 2012

Low cost development and applications of the new NRO donated telescopes.

Copyright 2012 Robert Clark


Credit: simulated image of Hubble-class telescope at Mars from NASA images.


NASA gets two military spy telescopes for astronomy. 
By Joel Achenbach, Published: June 4 
The announcement Monday raised the obvious question of why the 
intelligence agency would no longer want, or need, two Hubble-class 
telescopes. A spokeswoman, Loretta DeSio, provided information 
sparingly. 
“They no longer possessed intelligence-collection uses,” she said of 
the telescopes.

http://www.washingtonpost.com/national/health-science/nasa-gets-military-spy-telescopes-for-astronomy/2012/06/04/gJQAsT6UDV_story.html 

The explanation clearly is that Hubble scale telescopes are now 
obsolete for surveillance as I earlier argued, [1].


Asteroid Detection for Planetary Defense and Asteroidal Prospecting.

 A useful application of the new scopes would be detection of asteroids for planetary defense purposes, and for the new asteroid mining ventures. For instance the wide field camera on the WISE mission satellite was able to find this Trojan class asteroid:

NASA's WISE Mission Finds First Trojan Asteroid Sharing Earth's Orbit.
07.27.11 
 The mirror on the new scopes is 100 inches compared to 16 inches for the WISE mission satellite, resulting in nearly 40 times greater collecting area and sensitivity.

 In fact, NASA might be able to have the satellite development be partially funded by the asteroid mining ventures. If so, then the development could be done much more cheaply with a commercial approach to their development.

 Indeed Planetary Resources referred to the NASA WISE satellite in stating they could produce comparable telescopes to the WISE at 1 to 2 order of magnitude lower costs:

Billionaire-backed asteroid mining venture starts with space telescopes.
The key factor is the cost: Lewicki noted that an imaging instrument like NASA's Wide-field Infrared Survey Explorer would typically cost hundreds of millions of dollars. "We're looking to go one to two orders of magnitude below that," he said.  [2]

 For a Hubble-class telescope this would be reduced at least to the few hundred million dollar cost range, thus solving the funding problem NASA has for deploying such scopes. That the scopes could indeed be produced at such reduced costs is given credence by the fact that SpaceX was able to cut development costs both for their launchers and their spacecraft by an order of magnitude by following a commercial approach to their development. 

 Note also that Hubble was designed and built in the 1980's, 25 years ago. From Moore's law there have been major reductions in size and cost of electronic components since then, which  further supports the idea the development costs can be done much more cheaply now for the instruments than was the case for Hubble.

 For the launch costs, Hubble was done by the shuttle with a ca. 20 mT payload capacity. So a Hubble-class scope launched just to LEO could be done by any of the current largest launchers with a 20 mT capacity to LEO, at costs in the $200 million range. 

 However, Hubble was just barely above 10 mT in weight, at about 11 mT. Reportedly these new scopes weigh less than Hubble and with the reduction and size and weight in electronics since the time Hubble was developed, these new scopes quite likely could be brought in at 10 mT or less. In that case they could be launched to LEO by a Falcon 9 at a $50 million launch cost.

Mars Imaging Satellites.

 Another useful application of one of the scopes would be for a Mars orbital satellite. Again as developed by Planetary Resources in a commercial approach to the development it could be done for a few hundred million dollars. 

 The mirror on the current highest resolution Mars satellite Mars Reconnaissance Orbiter(MRO) has a 20 inch diameter with a resolution on the Mars surface of 25 centimeters, about 10 inches. Then the 100 inch diameter on the Hubble class scope would give a resolution of 5 centimeters, about 2 inches. 

 MRO came within 100 km of the surface at periapsis during aerobraking on Mars, [3], while its final orbit was at about 300 km. However, MRO did not do imaging at closest approach during aerobraking. If a Hubble class scope did such imaging, then at 100 km altitude it could get sub-inch resolution at periapsis.

 Mars orbiting satellites typically have both wide field and narrow field cameras, with the wide field cameras giving much courser resolution than the narrow field. However, these new scopes reportedly can give resolution nearly as good as Hubble even with a wide field. 

 This is important because for the Mars orbiters when taking their highest resolution images with the narrow field cameras, the coverage of the surface is quite spotty. However, with these new scopes having wide field capability at high resolution you can get entire surface coverage at high resolution. This would require high data throughput of course which should now be possible with state of art computer storage density and processing speeds.

 For the launch cost, Robert Zubrin suggests the Falcon Heavy could send 14 mT to Mars orbit with a conventional hydrogen-fueled upper stage, say of Centaur-type, [4]. A single one of the current largest Centaurs at 20 mT gross mass probably wouldn't do it though. You would need two, either parallel or serially staged. At a Centaur cost of $30 million, assign $60 million for the cost of the upper stage. Then with a $100 million cost of the Falcon Heavy, the launch cost would probably be under $200 million, when you add on the cost of integrating the Centaurs to the rest of the vehicle.

Speculations on the Next Mars Imaging Satellites after the Hubble-class.

 Because of the ever improving resolution of orbital satellites sent to Mars, I once wrote rather tongue-in-cheek that we will soon be able to resolve Martian microbes from orbit, [5]. However, remarkable new research might imply such astonishing resolution near term might actually come to pass. 

 To get such high resolution from orbit would require an impractically large mirror, one might  think. This is because the diffraction limit of classical electromagnetic wave theory puts limits on the degree of resolution you can get for a given size mirror. However, new research in "negative refractive index" materials shows using quantum mechanics you can get resolution actually beyond the diffraction limit. The result is you can get much better resolution for a given size mirror than previously thought possible, [6], [7].



  Bob Clark


REFERENCES.

1.)Newsgroups: sci.astro, sci.physics, sci.space.policy, sci.astro.amateur, us.military.army 
From: Robert Clark <rgregorycl...@yahoo.com> 
Date: 23 Apr 2007 02:49:39 -0700 
Subject: Orbital surveillance satellites now exceed 1 inch resolution. 


2.)Billionaire-backed asteroid mining venture starts with space telescopes.
23 Apr, 2012 11:37pm, EDT

3.)Mars cameras debut as NASA craft adjusts orbit.
MISSION STATUS REPORT
Posted: April 13, 2006

4.)The Use of SpaceX Hardware to Accomplish Near-Term Human Mars Mission.

5.)Newsgroups: sci.astro, sci.physics, sci.geo.geology, alt.sci.planetary, sci.astro.amateur
From: "Robert Clark" <rgregorycl...@yahoo.com>
Date: 10 Jan 2007 09:12:09 -0800
Subject: We will soon be able to resolve Mars microbes from orbit. ;-)

6.)Negative index metamaterials.

7.)Superlens.






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