Will each Sprite have it's own frequency?
Since these Sprites are operating in the Amateur satellite bands, how will you license them? How will you handle the frequency coordination of these transmitters?
The information that Zac and his team provided to AMSAT News Service in May, 2011 reported that the Sprite prototypes that were deployed on the ISS operated with 10 milliwatts of RF power at 902 MHz using MSK modulation (minimum-shift keying) with a chipping rate of 50 kbps.
Copy of original release below ...
-- 73 de JoAnne K9JKM k9jkm@amsat.org Editor, AMSAT News Service
SB SAT @ AMSAT $ANS-149.03 Cornell University Chip Satellite Team Invites Ham Radio Collaboration
AMSAT News Service Bulletin 149.03 From AMSAT HQ SILVER SPRING, MD. May 29, 2011 To All RADIO AMATEURS BID: $ANS-149.03
Cornell University Chip Satellite Team Invites Ham Radio Collaboration
A group of Cornell University-developed, fingernail-sized satellites may travel to Saturn within the next decade, and as they flutter down through its atmosphere, they will collect data about chemistry, radia- tion and particle impacts.
Three prototypes of these chip satellites, named "Sprite," were mount- ed on the International Space Station during a recent spacewalk. The thin, 1-inch-square chips are mounted to the external Materials International Space Station Experiment (MISSE-8) pallet, exposing them to the harsh conditions of space to see how they hold up and transmit data.
Zac Manchester at Cornell University explained that the chips transmit as beacons with 10 milliwatts of RF power at 902 MHz using MSK modu- lation (minimum-shift keying) with a chipping rate of 50 kbps. The Cornell team invites AMSAT satellite operators to collaborate with this experiment to determine conditions in which the low-power signal has been detected on the ground.
The Cornell ground station consists of a 18 dBi yagi with a GNU Radio and USRP receiver (http://www.ettus.com/products). A significant challenge is that the MISSE-8 pallet the chips are on is mounted on the anti-nadir side of the space station, facing away from the earth. The team is hoping to be lucky to catch some kind of reflection off the ISS structure.
Beyond being able to detect the signal on Earth, decoding the message requires signal processing. The chips all transmit on the same frequency, each with it's own PRN code. The Cornell team uses these codes to differentiate each one, as well as to provide signal proces- sing gain. At Cornell, data is being recorded and post-processed with a standard PC.
To track these chip satellites just use the ISS keplerian elements because they are mounted on the space station.
Mason Peck, Associate Professor Mechanical and Aerospace Engineering at Cornell University wrote, "Receiving the full sequence of data per se is not of interest, but the mere reception of it (a single digital bit, for us), indicates successful transmission. If you would like to serve as one of the lucky few to try detecting this signal, please follow up with Zac Manchester (zrm3@cornell.edu). We definitely welcome the collaboration of HAM operators."
More information be found at these sources: http://tinyurl.com/3fs5ks7 (spacemart.com) http://www.spacecraftresearch.com/blog
[ANS thanks Zac Manchester and Mason Peck at Cornell University for the above information]
/EX