Posts Tagged ‘darpa’


Thursday, April 11th, 2013

Remember real-time DVR for satellite radio? It would grab the past and future (+/-3 minutes) so you could go back a little to hear what you missed. The satellite TV ones are awesome, too. Go back as far as you like, skip the ads, etc. So we’re taking spaced-based tech and adding some magic on the ground to make it better.

I don’t have a GPS device. I use my iPhone and Google Maps. Without an Internet connection, it won’t be help — unless you download where you know you’ll be with a connection. Like remote national park. Download the maps and the GPS will still kick-in and guide you.

What if you lose your GPS connection? Think long tunnel or deep gorge — or the bad guys putting the jam on your signal. Enter DARPA and it’s new prototype timing & inertial measurement unit (TIMU)

DARPA researchers at the University of Michigan have made significant progress with a timing & inertial measurement unit (TIMU) that contains everything needed to aid navigation when GPS is temporarily unavailable. The single chip TIMU prototype contains a six axis IMU (three gyroscopes and three accelerometers) and integrates a highly-accurate master clock into a single miniature system, smaller than the size of a penny. This chip integrates breakthrough devices (clocks, gyroscopes and accelerometers), materials and designs from DARPA’s Micro-Technology for Positioning, Navigation and Timing (Micro-PNT) program.

Three pieces of information are needed to navigate between known points ‘A’ and ‘B’ with precision: orientation, acceleration and time. This new chip integrates state-of-the-art devices that can measure all three simultaneously. This elegant design is accomplished through new fabrication processes in high-quality materials for multi-layered, packaged inertial sensors and a timing unit, all in a tiny 10 cubic millimeter package. Each of the six microfabricated layers of the TIMU is only 50 microns thick, approximately the thickness of a human hair. Each layer has a different function, akin to floors in a building.

The TIMU is tiny and so very cool.

“Cellophane Telescope” by Seymour Sun

Wednesday, October 3rd, 2012

The payload deployment test shown above moves the FalconSAT-7 mission forward, which is scheduled for 2015. Why is this “cubesat” important? It uses diffraction instead of refraction or reflection and it is becoming a real alternate to a large space-based observatory in studying the Sun’s chromosphere — especially in the H-alpha wavelengths.

The cubesat is being developed by the U.S. Air Force Academy and NASA’s Goddard Space Flight Center, among others, including the NRO, DARPA, AFOSR, AFIT, MMA Design and AFRL.

A photon sieve is a novel optical element consisting of a flat opaque sheet with millions of tiny holes. Light passing through these holes is focused in a similar manner to a lens or a mirror. Photon sieves have several key advantages over those more conventional optics:

  • Focusing can be achieved from a flat, thin sheet that can be unfurled from a very compact, lightweight package
  • Surface quality tolerances are orders of magnitude more relaxed
  • The fabrication costs are much lower

The trade-offs include:

  • Lower efficiency / loss of light
  • Narrow bandwidth giving what are essentially grayscale images

The photon sieve will have the following design parameters:

  • 200mm diameter, 400mm focal length, 656.3nm wavelength
  • 2.5 billion holes ranging in size from 2-277 microns
  • 50% fill factor, 30% focusing efficiency

The telescope has a relatively simple design due to space constraints and has:

  • 4 µrad resolution which equates to 600 km at Sun surface
  • ~0.1 degree field of view (about a 1/5th of the Sun’s disk)

Clockwise from top left: A 4-inch photon sieve lit by laser light. The focal spot produced. A magnified image of the central 25mm. An image of a resolution chart produced by the sieve. An interferogram of the wavefront that indicates perfect focusing capability.

Dead Satellites and Onions

Tuesday, September 25th, 2012

If the head of the USAF Space Command has doubts, our friends at ViviSat and MDA ought to be concerned about their satellite-servicing business proposition. Via Popular Mechanics

It sounds like such a good idea: When satellites run out of fuel, send up a robot to top them off instead of launching a new one. NASA and DARPA have active programs researching this concept. But Gen. Shelton, as head of Air Force Space Command, says he doesn’t see the need. By the time a satellite runs out of propellant, the hardware is about 22 years old. After that much time, he argues, the solar arrays have degraded and the computers are relics. “Now we want to go up and refuel it?” he asks. “When you peel back a few layers of this onion, it makes less sense to me.”

The Space Command celebrated their 30th last week in Colorado Springs and their opinions do matter. However, with DARPA and NASA remaining interested, the business still has reason to go forward. Except for Intelsat.

Hydrazine Vampires?

Monday, October 24th, 2011

Well, not exactly vampires. In keeping with the spirit of the season, Jamie Zawinski chose to call DARPA’s Phoenix Program “space vampires,” which was picked up by Boing Boing and spun up as “vampire satellite,” a la zombie satellite.

Communication satellites in geosynchronous orbit (GEO), approximately 22,000 miles above the earth, provide vital communication capabilities to warfighters. Today, when a communication satellite fails, it usually means the expensive prospect of having to launch a brand new replacement communication satellite. Many of the satellites which are obsolete or have failed still have usable antennas, solar arrays and other components which are expected to last much longer than the life of the satellite, but currently there is no way to re-use them.

The goal of the Phoenix program is to develop and demonstrate technologies to cooperatively harvest and re-use valuable components from retired, nonworking satellites in GEO and demonstrate the ability to create new space systems at greatly reduced cost. Phoenix seeks to demonstrate around-the-clock, globally persistent communication capability for warfighters more economically, by robotically removing and re-using GEO-based space apertures and antennas from de-commissioned satellites in the graveyard or disposal orbit.

I suspect we’ll get a response from the good people at ViviSat and MDA in Canada. Although they’re talking about on-orbit refueling, not scavenging for parts.