July 30, 2012
Credit: Credit: Virgin Galactic
Frank Morring, Jr. Washington
If all goes as planned, a United Launch Alliance Atlas V will lift off from Vandenberg AFB, Calif., later this week with a classified National Reconnaissance Office (NRO) payload on board. Already tucked into a special carrier suspended from a helium tank in the rocket's upper stage, right next to the RL-10 engine, are 11 tiny satellites riding to orbit as secondary payloads.
Some of the cubesats are flying NRO missions, but four were built at U.S. universities by engineering students and all of them were integrated into their spring-loaded deployers at California Polytechnic State University.
Cal Poly developed the Poly-PicoSatellite Orbital Deployer (P-POD) used by most cubesat builders these days. Essentially square tubes that eject as many as three 10 X 10 X 10-cm cubesats at once, P-PODS can be tucked into extra space on any launch vehicle's upper stage where they don't get in the way of the primary mission.
In the NRO launch, NASA's Office of Education arranged for the university cubesats to fly on the Atlas V Aft Bulkhead Carrier developed with funding from the NRO Office of Space Launch. The civilian space agency finds rides to orbit for student-built spacecraft under its Educational Launch of Nanosatellites (ELaNa) program, which sends the educational tools to space at essentially no cost to the schools that built them.
The ELaNA process illustrates a big advantage of small satellites—their low cost to orbit.
“Smaller satellites are not only generally cheaper to build, but they're also cheaper to launch,” says John Roth, vice president for business development at Sierra Nevada Space Systems, which specializes in smallsats. “And since the launch cost is a large percentage of mission cost, if you can get your satellite as a secondary payload on a launch—or at least get it on a small launch vehicle rather than a large launch vehicle—you save tons of money. You save probably more than the cost of the satellite just in the launch cost.”
A NASA-built cubesat is already in orbit on Japan's third H-II Transfer Vehicle (HTV-3) after its July 20 launch from the Tanegashima Space Center, but it will not be deployed until September or October. Developed at Ames Research Center, the Technical and Educational Satellite (TechEdSat) will be jettisoned into space from the exposed “porch” of the Kibo Japanese Exploration Module by a new version of the P-POD called the Small Satellite Orbital Deployer (J-SSOD).