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DoD: a cloud of CUBESAT's

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  • DoD: a cloud of CUBESAT's

    Four of these assigned to the Special Operations Command were tested by the Special Operations Command after launch on the Falcon 9/Dragon flight last December. In all, 8 cubsats went up on that flight mounted between the F9's second stage and the Dragons cargo trunk.

    Commercial clouds are also very possible given how cheap cubesats are, and because they're so light large numbers can be launched at once, even co-sited under a larger payload.

    Damned interesting concept - a cloud of dozens to hundreds of miniature cubesats instead of a few large satellites. Some cubesats are as small as 8x8x8 inches - the 1U size. Other sizes are 1.5U, 2U and 3U, each depicting the cubesats length as a multiple of 8 inches.

    Depiction of a very limited lunar orbit cloud at bottom.

    Aviation Week....

    Cubesats Tapped For Orbital Networks

    If scientists at the U.S. Defense Advanced Research Projects Agency (Darpa) get their way, in a few years there may be networked clusters of dozens or even hundreds of small, cheap, easily replaceable satellites working together in place of the large, expensive and difficult-to-replace birds now in orbit.

    Darpa researchers have worked for several years and spent tens of millions of dollars on a program known as “System F6” (Future, Fast, Flexible, Fractionated, Free-Flying Spacecraft), whose goal is to create clusters of satellites linked by ad hoc wireless networks allowing them to autonomously share tasks such as processing, data storage, sensing, communications relay and navigation, while trading off missions if any satellite fails or falls out of orbit. Darpa wants to conduct an orbital demonstration in 2014-15. Raytheon announced in July that its BBN Technologies segment has been awarded $2.4 million to design the network the satellites will use.

    “We’re building an embedded computing cloud in the sky with real-time requirements and multiple users,” says Craig Partridge, principal investigator at Raytheon BBN Technologies.

    While Darpa hasn’t specified the project’s size, Raytheon is designing the network for clusters of up to 100 satellites in which each would have 10 applications running at one time, both consuming and producing data. And while each node on the network operates independently, Partridge says that if parts of the network go down, content will still flow across those that remain. With the satellites in orbit, users on the ground “can always upload new missions to them. . . . We view it as a dynamic programming environment,” he adds.

    Darpa didn’t return repeated calls for comment. Nevertheless, the idea here is to use clusters of cubesats, tiny satellites that cost anywhere from a few thousand to a few hundred thousand dollars each, and weigh a few pounds at most. University research teams have been launching the mini satellites into space for several years, and the Army, Air Force and Navy have experimented with the technology. (For an article on the U.S. Army’s work with cubesats, see DTI June 2009, p. 14.)

    Even U.S. special forces have cubesats in low Earth orbit. Last December, U.S. Special Operations Command (SOC)sent up four cubesats on the SpaceX rocket to demonstrate the transmission of tagging, tracking and locating data, according to Doug Richardson, a civilian official at SOC, who revealed the information at the Special Operations Forces Industry Conference in Tampa, Fla., in May. Richardson did not provide additional details.

    “The military is moving toward using cubesats more often,” says William Ostrove, space systems analyst at consultant Forecast International. It’s not only the cost or the ability to upgrade quickly, he says, but the fact that they’re tough targets for enemies to shoot out of the sky.

    “It’s hard to hit a target that is roughly the size of a coffee cup screaming across the sky,” says Brian Zufelt of the University of New Mexico, who works with the Air Force Research Laboratory and NASA on cubesat programs. Zufelt’s lab will orbit three 4 X 4 X 4-in. cubesats this fall. The satellites will be built and launched for $35,000.

    Zufelt says one of the ideas kicking around his team is to use a cubesat to develop a way to shoot a 1-watt laser from low Earth orbit to a soldier on the ground, who would receive the transmission with “a simple telescope and a photon detector attached to the lens.” While the laser would disperse at that range, “the photons would make it to the telescope and be able to transmit communications. So you would have an unjammable communication link that is pretty much undetected,” Zufelt says.

    Commercial off-the-shelf equipment works well in the cubesats, so much so that “you can put what you find in your typical Android phone and shoot it into low Earth orbit,” he adds.

    Currently, the biggest limitation to the technology is power-generation capabilities that keep the applications on the vehicle functioning, since the satellite is too small to equip for long missions with the power technologies currently in use. “That’s going to be the limitation for a long time,” Zufelt advises. “Anything the military wants, the technology is there that can fit into that structure, but the issue is power.”
    Dr. Mordrid
    ----------------------------
    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  • #2
    Nice concept, but I'm a bit fearful about anything that is considered disposable... There is enough junk up there now... I personally feel that for any new concept, its end-of-life solution should be considered at the design stage.
    pixar
    Dream as if you'll live forever. Live as if you'll die tomorrow. (James Dean)

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    • #3
      These will probably use ion thrusters, which can be made pretty small. MITnews did an article on this exact application last year. Pic below.

      Link....

      Right now, 10 to 15 Rubik’s Cube-sized satellites are orbiting high above Earth. Known as cube satellites, or “CubeSats,” the devices help researchers conduct simple space observations and measure characteristics of Earth’s atmosphere. One advantage is that they are relatively cheap to deploy: While launching a rocket may cost between $50 million and $300 million, a CubeSat can “piggyback” onto a large rocket platform at an additional cost of as little as $40,000. But their small size also means they lack on-board propulsion systems, which is why they generally remain locked to a particular orbit.

      That could soon change, however. Paulo Lozano, the H.N. Slater Assistant Professor of Aeronautics and Astronautics at MIT, is designing a tiny propulsion system that could allow the satellites, which weigh about a kilogram and are used for tasks that don’t require precise orbit control, to travel great distances and perform more serious tasks, such as searching for planets outside our solar system. The technology, which is based on the process of extracting and accelerating charged ions, or atoms that have gained or lost an electron, could make CubeSats much more useful for organizations or countries that until now have had limited access to space.
      >
      Lozano’s design relies on electrospraying, a physics process that uses electricity to extract positive and negative ions from a liquid salt that is created in a laboratory and serves as the system’s propellant. The liquid contains no solvent, such as water, and can be charged electrically with no heat involved. Whereas other electric propulsion systems charge the ions in a chamber on the satellite, the ionic liquid in Lozano’s design has already been charged on the ground, which is why his system doesn’t need a chamber.

      Electricity is then converted from the main power source of the CubeSat, typically batteries or a solar panel, and applied to a tiny structure roughly the size of a postage stamp. This thin panel is made of about 1,000 porous metal structures that resemble needles and have several grams of the ionic liquid on them. By applying voltage to the needles, an electric field is created that extracts the ions from the liquid, accelerates them at very high speeds and forces them to fly away. This process creates an ionic force strong enough to produce thrust.

      Whereas chemical rockets waste too much propellant to reach a net change in spacecraft velocity, electric thrusters can do exactly the same mission using just a small fraction of the propellant. The only difference is one of time: Although electric propulsion is very fuel efficient, it is slower due to power limitations.

      “Eventually, you’ll run out of propellant, but that is the benefit of electric propulsion because it accelerates so fast that you don’t need a lot of it,” he said. “No other electric propulsion system would be so compact and efficient at the same time.”

      Because the mini-thrusters are scalable, thousands of them could be built into long, thin panels to produce thrust for a much larger spacecraft that requires low, but steady, acceleration. “There’s no impediment to making a whole table of them similar to a solar panel,” Lozano said. “This gives you a lot more flexibility in what you can do.”

      Lozano predicts that CubeSats using this technology will become a reality in less than three years. He plans to have a prototype of the mini-thruster in four to five months and hopes to begin testing it to measure performance metrics such as the velocity of the ions and their energy to figure out the force produced by the engine. Knowing this, researchers can estimate its efficiency. After Lozano delivers a prototype this year, his team will look for additional support to turn the design into a flight version.
      Dr. Mordrid
      ----------------------------
      An elephant is a mouse built to government specifications.

      I carry a gun because I can't throw a rock 1,250 fps

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