Monday, January 21, 2013

Planetary Resources Reveals Telescope Prototype

An artist's rendition of the Arkyd-100 in orbit.
Planetary Resources, the startup aiming to make billions of dollars mining platinum from asteroids in our solar system, recently revealed their prototype for the Arkyd-100 Space Telescope. A fleet of these telescopes will eventually be launched to search for minable, accessible, asteroids. It is an amazingly small and compact 11 kg satellite with small deployable solar arrays - significantly smaller than the prototype they previously debuted. The telescope is compact for launch, but can be extended several inches once deployed in space, increasing its focal length.

Among the most interesting revelations is the company's plan to use the telescope for laser communications rather than relying on a network of radio dishes. Laser communications is a really neat technique. Basically, instead of sending telemetry and images over modulated longer-wavelength radio waves (like most satellites do to communicate with ground stations on Earth), you use shorter-wavelength waves in the visible spectrum. This has many benefits:
  • Because shorter wavelengths have higher energy, you can transmit information at a much higher density, or data rate.
  • Radio and television stations transmit in the radio wavelengths, so anyone operating a radio transmitter needs a license to avoid interference. The optical spectrum has none of these restrictions.
  • Laser receptors/transmitters on the ground are much smaller and cheaper to build and operate than their radio counterparts.
  • For satellites with imaging payloads, the telescope can be used both as an optic to collect light (take images or receive information) and as a laser to send it (transmit images to the ground). there is no need for a separate radio antenna that takes up room and adds mass to a satellite.
The main drawback of laser communications is that water vapor in Earth's atmosphere absorbs waves in the visible spectrum (that's why it's dark on a cloudy day). Moreover, it requires extremely precise pointing in order to hit receptors on Earth. This is why long-range laser communications are currently only widely used in space-based satellite to satellite communications where water vapor is not an issue. However, if these obstacles can be overcome (by using continual weather analysis to find clear areas with no clouds and arid climates to transmit, and building robust stabilization systems to point the spacecraft), then laser communication can be an incredibly efficient and cheap option. Planetary Resources says it is under contract with NASA to develop this technology for use on future government-funded satellites.

The company says it hopes to sell its satellites to other companies to help fund its ultimate goal of retrieving and selling valuable platinum from an asteroid. I will certainly be watching as their design matures and progresses!

You can watch their informational video, which includes a small tour of their facilities, here.

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