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: There’ve been satellites orbiting Earth for half a century. But getting information to and from them is still a pain. Which is why Pentagon research arm Darpa is looking to finally hook the orbiting spacecraft up with reliable broadband connections. It’s part of a larger movement to extend terrestrial networks into space, and eventually build an ‘interplanetary internet.’ Darpa recently issued a request for information about supplying persistent broadband ground connectivity for spacecraft in low-Earth orbit. The idea would be to give these satellites a near-constant feed of 100 kbps or higher two-way connectivity, with end-to-end transmission latency of less than a second. Unlike most Darpa projects, which are meant to pay off years or decades in the future, this would be a near-term attempt. The agency wants the system operational in the 2012 to 2013 time frame. For years, Darpa—which backed much of the early research into the internet— has been working with other networking godfathers to put together an interplanetary internet. The protocol that the internet uses—TCP/IP—wasn’t really designed with space in mind.
For one, the delay times between nodes can be big. One way to geosynchronous orbit is 300 milliseconds at the speed of light, there and back over half a second of built-in network lag before anything else adds to it. That’s one reason why getting internet from satellites sucks right now.
Shock treatment
Brief electric shocks may help the body better respond to certain kinds of experimental AIDS vaccines, US researchers said. They used a device that looks like a handgun to inject vaccine along with three brief electrical pulses to open up cell membranes so that the vaccine can get inside. Researchers at the Aaron Diamond AIDS Research Centre in New York said the technique, called electroporation, may be particularly useful in delivering DNA vaccines, which use an infectious agent’s own genetic material to elicit an immune response. In their study, the researchers used a relatively weak experimental DNA vaccine designed in 2001 using four genes from an AIDS virus circulating in China. When the vaccine was given by injection alone, only 25% of participants developed any immune response. But in its latest trial in 2007-2009 when the same vaccine was delivered using electroporation, the immune response appeared far stronger. The study involved 40 people divided into five groups of eight. Three groups were given the vaccine in varying doses with the electric pulse. The fourth group...
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