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April 29, 2012

Carnival of Space 247 - Planetary Resources and other space blogging

1. Centauri Dreams offers the first of a 3-part post on Proxima Centauri, the nearest known star. Are we likely to find planets there?


Proxima Centauri (shown by the arrow) in relation to Centauri A and B. The latter appear as a single bright object at upper left. Credit: European Southern Observatory.




2. Simostronomy - T Draconis is a beautiful double star, but it is also a variable star.

3. Astrowow - Back to basics - the astronomy word of the week is "light-year".

4. The moon brightness changes dramatically every day, but is far from being linear. The full moon may be 4000 times brighter than the thin crescent moon. The reasons for this change ate explained in the Venus Transit article about the moon brightness. during a lunar month

5. Supernova condensate - How exactly would you enjoy a nice hot cup of coffee in zero gravity?

6. Supernova condensate - The announcement by Planetary Resources of their intentions to mine asteroids offers a possible relief for Earth's dwindling resources. Could it also eventually offer pathways to solar system colonisation?

The full repurcussions of all of this on Earth (especially on all manner of global economies!) remain to be seen, but one thing's for sure -- There's a fortune out in those rocks. Should asteroid mining develop into a large scale industry, it would become easily wealthy enough to look into ventures into the rest of the solar system. Logically the best place to start would be in the asteroid belt, where the huge abundance of raw materials trapped in asteroids may be quite readily accessible. As some have suggested, with a shallow gravity well to allow full access to all the resources there, a tiny world like Ceres may end up being a very rich world indeed.



Nextbigfuture - Planetary Resources plans to put mass produced 20 kilogram space telescopes into low earth orbit starting at the end of 2013 Some have criticized Planetary Resources as something that will lose a lot of money. I contend that it will be highly profitable even before they mine anything.

It will use laser communication to transmit information back. The lens look like an 9 inch (22 centimeter) diameter telescope.

They can point to the earth and get 2 meter resolution of the ground.

Planetary Resources can choose to make themselves very profitable before any material is mined. Satellite imaging, space telescopes and space data sales are markets that will work.

Overall, investment into civil government Earth Observation reached $5.9 billion in 2010—an all-time high.

Sales of commercial data reached $1.3 billion in 2010 and continue to grow strongly. The U.S. government remains by far the largest consumer of commercial EO data, primarily for defense purposes through the National Geospatial-Intelligence Agency (NGA). Following consolidation in the U.S. industry, the industry has grown strongly—by a 23 percent compound annual growth rate during the last five years—largely in response to growing requirements for defense applications. Furthermore, the private sector is showing signs of increased development, particularly for location-based applications.

The Arkyd 102 telescope in person (top) and in mocked-up artwork from Planetary Resources (bottom)

7. Nextbigfuture - Planetary Resources will be putting up hundreds of inexpensive space telescopes with 9 inch mirrors, 2 meter resolution and sub-arcsecond pointing. The passive constellation method for boosting image resolution could achieve centimeter resolution. When Planetary Resources adds some fine station keeping capabilites, they will be able to create massive space telescope interferometers. They will add some starshade satellites and be able to image exoplanets. 1 kilometer resolution would be a hypertelescope array about 10,000 miles across. That would mean a 100 million pixel image of an exoplanet (planets in solar systems up to about 10 light years away). They would be able to look even further at somewhat lower resolution

Over the past several years, much progress has been made in the development of the Intensity Correlation Imaging approach to ultra-fine resolution imaging. In this paper, we consider the design of a LEO-based observatory of small telescopes using the Intensity Correlation Imaging technology to achieve 1 centimeter resolution imaging of objects in geosynchronous orbit. We formulate the system Modulation Transfer Function (MTF) and then seek to optimize u-v plane coverage by the design of passive, LEO orbits. An adaptive random search technique is used to find constellation designs that offer twice the rate of u-v coverage as earlier results.

EXO-EARTH IMAGER (EEI)


* visible “portraits” of exoplanets can be obtained in 30 minutes of exposure, using a 150 kilometer hypertelescope with 150 mirrors of 3 meters.

* 10 km resolution at 4.37 Light years. That's about what our satellite p10 .hotos took back in the 1960's. Certainly high enough resolving power to image landforms, islands, forests, whatever else is going on. This would require a hypertelescope array that is 1,500 miles across.

1 kilometer resolution would be a hypertelescope array about 10,000 miles across. That would mean a 100 million pixel image of an exoplanet.

* To resolve 30 foot objects looking 4.37 light years away the elements making up a telescope array would have to cover a distance roughly 400,000 miles wide, or almost the Sun's radius. The area required to collect even one photon a year in light reflected off such a planet is some 60 miles wide. To determine motion of 2 feet per minute — and that the motion you’re seeing is not due to errors in observation — the area required to collect the needed photons would need to be some 1.8 million miles wide. [NOTE - I do not think there would be enough photons coming off of such a small object at light year distances. This is why the hypertelescope expert talks about massive telescope arrays to resolve neutron stars. They are small but are emitting enough photons for an image]

8. Nextbigfuture - Planetary Resources coverage with infographic, video and picture of the Arkyd space telescope 102

9. Nextbigfuture - Part of the coverage of the Planetary Resources Press conference

10. Nextbigfuture - Coverage of the Planetary Resources Press conference, Part 1

11. Nextbigfuture - Coverage of the Planetary Resources Press conference, Part 2


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