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KickSat CubeSat to Deploy Smallest Earth-Orbiting Satellites

03/07/2014

When the third SpaceX ISS resupply mission launches on March 16 from Cape Canaveral, it will carry the 3U KickSat CubeSat into orbit. NASA TV is scheduled to broadcast the launch live. If all goes according to plan, KickSat, in turn, will release 200 “Sprite” satellites — each about the size of a small cracker — into orbit. They will become the smallest Earth-orbiting satellites ever. Zac Manchester, KD2BHC — a Cornell University PhD student in aerospace engineering — is heading up the project, which was funded via Kickstarter.

“Our goal is to dramatically lower the cost of spaceflight, making it easy enough and affordable enough for anyone to explore space,” the KickSat project website proclaims. “We can do this by shrinking the size and mass of the spacecraft, allowing many to be launched together.”

The tiny Sprite spacecraft will be single-function, short-lifespan units operating on 437 MHz. Each is essentially a double-sided printed circuit board measuring 3.5 cm × 3.5 cm, incorporating a microcontroller or two, radio, and solar cells. Each can carry single-chip sensors, such as thermometers, magnetometers, gyroscopes, and accelerometers.

All Sprites operate on the same frequency — 437.240 MHz — and use Code Division Multiple Access (CDMA). Transmitters run 10 mW output of minimum shift keying (MSK) modulated binary data, with each data bit modulated as a 511 bit pseudo-random number (PRN) sequence (The ITU emission designator is 50K0G1D).

Andy Thomas, G0SFJ, points out that the Sprites will only operate when in sunlight. “Characteristically they have a 60 kHz bandwidth, and so narrowband receivers are not of any use to receive them,” he explained in a tutorial that describes plans for a simple Earth station. “Therefore, the receiver of choice is a software defined receiver.”

When KickSat reaches orbit, it will perform a “de-tumble” maneuver and establish communication with Cornell University’s ground station. After everything has been checked out, the spacecraft will be put in a sun-pointing attitude and spun up to maintain that attitude. Then a command signal from the ground will trigger deployment, and the Sprites will be released as free-flying spacecraft. The Cornell ground station in Ithaca, New York, will monitor telemetry and sensor measurements from the individual Sprites, with assistance from several other Amateur Radio ground stations around the world.

Due to their low orbit, the Sprites will have short lifetimes, perhaps as long as six weeks in a best-case scenario but possibly a lot shorter, depending on atmospheric conditions.

KickSat is being planned as a technology demonstration mission for the Sprite spacecraft. It’s being launched through NASA’s Educational Launch of Nanosatellite (ELaNa) program. The KickSat project was founded in 2011 by members of the Space Systems Design Studio at Cornell University and is an outgrowth small spacecraft research that has been conducted there since 2007.

The British Interplanetary Society offers a KickSat Technical Summary on its website.

 



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