[amsat-bb] Re: KickSat - a personal spacecraft of your own in space

JoAnne Maenpaa k9jkm at comcast.net
Mon Oct 10 07:29:21 PDT 2011

> 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 at 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
May 29, 2011
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

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 at cornell.edu). We definitely welcome 
the collaboration of HAM operators."

More information be found at these sources:
http://tinyurl.com/3fs5ks7 (spacemart.com)

[ANS thanks Zac Manchester and Mason Peck at Cornell University for 
 the above information]


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