The cubesat team at the University of Louisiana is in the process of defining its second mission for its cubsat project. The team has decided to fly a cubesat that has a educational component. We are asking for ideas that would excite K through 12 students that can be flown on a cube sat i.e. 1 watt of dc power in a 4 inch cube.

DIGIPEATING MISSION: Please consider an AX.25 packet digipeater on 145.825 to continue to add to the educational amateur satellite constellation there. With multiple satellites on one frequency providing a generic bent-pipe digipeater like PCSAT,ANDE and RAFT, studnets would have dozens of passes per day to chose from for school experiments instead of just a few. Remember PCSAT is only alive 3 weeks out of the year, and ANDE and RAFT are all so low as to burn up in a year or less, and the digipeater on ISS is inoperative.

So we need a pipeline of university satellites targeting this continuing 145.825 digipeating mission so that new satelites replace or add to old ones. If we can get up to 6 satellites doing the same thing on that same frequency, then we could guarantee students worldwide access to at least one of them during any CLASS hour anywhere at any time.

INTERNET LINKED GROUND STATION NETWORK: In addition, we have a worldwide system of ground stations capturing the downlink on 145.825 and feeding it live to the internet so that any one school's satellite can be seen at any time over any country live. This also makes it much better in academia, so that classes are not limited to access to their satellites only a few times a day but over any other ham radio country as well.

NO SPECIAL HARDWARE: In addition to using 1200 baud AX.25 which almost every ham radio operator has access to, ground stations these days do no even need any special hardware or TNC. Soundcard packet implementations can be used so that schools only need a laptop and a radio to participate.

USER MISSIONS: Making the sateellite be a digipeater does not restrict the applications. Any digital application can be used simply by the application on the gorund. The satellite is only a bent pipe relay. SCHOOL-to-SCHOOL communications, BBS messaging, APRS position and status tracking of mobiles, boats Hikers, etc... ALL downlinks available real time on the internet (see http://pcsat.aprs.org ) Any future student applications can use this bent pipe transponder. Consider the Naval Academy's plan to deploy ocean going environmental sensor buoys to digipeat their data back to the school from anywhere in the world on this channel (see http://www.ew.usna.edu/~bruninga/buoy.html ).

STUDENT PROJECTS: An advantage of this type project to other schools is that those schools that cannot affort to build a satellite, can isntead have students building applications to USE the existing 145.825 relay system and internet data collection.

AUX PAYLOADS: In addition, the pcaket up and downlink can be used for serial data to any additional spacecraft experiment. PCSAT-1 had a GPS on its serial port. ANDE and RAFT have text-to-speech synthesizers (40 mA) that can speak special packets sent to them. A Naval Academy favorite packet transmitted by my students is "Go Navy, Beat Army" ... Etc The advantage of the packet-to-voice synthesizer is that all students can hear it, not just those with packet.

KISS PRINCIPLE. And the neat thing is that to do all of the above the satllite only needs a RX, TX and a TNC. No special software or CPU on board since modern TNC's have all of the above built in. Telemetry, beacons, command/control, remote password protected logon by the command station, digipeating, serial port access, 8 bit parallel I/O, serial port, etc. The only problem is that a standard off-the-shelf TNC such as the KPC-3+ is hard to fit in a 4" cube. Though it could be hacked....

LASTLY, operating up and down on 145.825 has a 9 dB advantage in the link budget BOTH ways to stations with simple OMNI antennas compared to using UHF. A 2 watt transmitter can easily be heard on an HT. And since the TX is only on for brief TX packet bursts only over the 10% of the world that is amateur radio populated, and since even over the USA, the peak load on the transmitter cannot exceed about 30 or 40% due to simplex digipeating, the overall TX load on the small satellite is only 3% of nominal TX power, so even a 2W TX could be used and only require an average orbit power of .12W, easy for a cubesat. You can further reduce that by limiting most modes to daylight (school) hours only and not wasting power in the dark.

MOBILE SATELILTE OPERATIONS: And lastly, these satellites provide the first viable mobile AMSAT communicaitons capability since they can be heaerd by a mobile whip antenna. In today's times, many hams can only find time to oeprate ham radio while mobile. We should b e designing a constellation of satellites on 145.825 to give them the coms pipeline they need.

All of our PCSAT,ANDE and RAFT designs based on the above can be found via our web pages. Simply GOOGLE for ANDE OPS and you should find it. It has links to all the satellites.

Bob, WB4APR US Naval Academy Satellite Lab

At 09:38 AM 1/11/2007, Nick Pugh wrote:

Hi Amsaters

The cubesat team at the University of Louisiana is in the process of defining its second mission for its cubsat project. The team has decided to fly a cubesat that has a educational component. We are asking for ideas that would excite K through 12 students that can be flown on a cube sat i.e. 1 watt of dc power in a 4 inch cube. In addition to the education component the team is thinking of flying a high efficient radio per haps bpsk with a forward error corrected code with Eb/No of < 3 db. Again here we are asking for input in the mission definition and help in the implementation including pier review.

Please put your vision in gear and help us. thanks nick K5qxj

Hi Nick,

Here is a wild idea for you. The Nintendo DS Lite video game has a built-in wireless Instant Messaging (IM) capability that runs at 2.4GHz using standard WiFi. It would be really cool for kids to be able to chat with other kids via satellite using their Nintendo game.

73, Tony AA2TX