An Atlas V rocket was set to launch sometime between 5 and 9 a.m. Thursday, Oct. 8, from Vandenberg’s 3-East Launch Complex. It’s 20 stories tall, weighs just less than a million pounds when fueled, and rises skyward by burning liquid oxygen to generate 860 million pounds of thrust at liftoff.
The launch carries two payloads. One is a satellite for the National Reconnaissance Office (NRO)—it’s classified, although NRO satellites are often equipped with radar, optics, and communications arrays for imaging and reconnaissance.
The secondary payload is a baker’s dozen of CubeSats. They’re miniature satellites, about 10 centimeters to a side roughly the size of a toaster. Nine come from the NRO, and NASA sponsors four others.
BisonSat, one of the four CubeSats sponsored by NASA, comes from a Salish Kootenai College, a tribal school in Pablo, Mont. Sixteen students, mentored by four faculty from the engineering department, designed the tiny satellite over the course of four years.
“Our team is somewhat unique in the different ones that NASA has selected,” said Tim Olson, chairman of the division of sciences at Salish Kootenai. “Perhaps the smallest college, definitely the first tribal college.”
BisonSat, like a compass, orients itself through passive magnetic stabilization. When it’s over the northern hemisphere, it’ll look downward, toward the Earth; when it’s over the southern hemisphere, it’ll look off into space.
The students designed the satellite’s camera. It uses a bayer detection filter, like most commercial-grade cell phone cameras, creating jpeg files from a grid of red, green, and blue pixels.
A computer model helps the students and faculty at Salish Kootenai predict where BisonSat is over the Earth and in which direction it’s oriented. They’ve constructed a satellite ground station by which they can send up the command to take a photo.
When BisonSat passes back over Montana, it can talk briefly with the team, passing encrypted packets of information back and forth over ham radio frequencies. The transfer rate, at 9,600 bits per second, is about as fast as dial-up Internet.
On Earth, the images can be parsed—Olson hopes to analyze them with spectroscopy, working backwards from color data to suss out the kind of terrain captured by the camera.
If all goes well, BisonSat will orbit for 10 years before it hits the atmosphere and burns up. That’s an outside figure. A satellite so small, Olson said, doesn’t have much room for redundant systems. One hit from a charged particle to a circuit board, he said, could spell game over. On the inside, he’s hoping for at least a couple of months of operation.
“It’s just the luck of the draw, to a certain extent,” he said.
This article appears in Oct 8-15, 2015.
