miércoles, 24 de noviembre de 2010


For Radio Operators: Overview


The FASTRAC mission is divided into two basic phases. Both mission phases rely heavily on the participation of the amateur radio community.
The first phase is the science portion of the mission. During this phase the two satellites will be sharing GPS data as long as they are within range of each other. The GPS data will be processed on board each satellite and then stored in flash memory to calculate an on-orbit relative navigation solution. Also, the satellites will be performing attitude determination with the GPS receiver. FASTRAC 1 will be firing the micro-discharge plasma thruster whenever the thrust vector is within 15 degrees of the anti-velocity vector. The data will be relayed to the ground when the satellite is in communication with a ground station. A coordination plan is being developed so that participating amateur radio ground stations can play a major role in collecting this data and relaying it back to this Web site.
The second phase of the mission begins by reconfiguring the satellites for use by the amateur radio community. The satellites will be reconfigured so that they can be used as digipeaters and form part of the Automatic Position Reporting System (APRS) network. The capabilities of these satellites are governed largely by the functionality of the Kantronics KPC9612-Plus TNC. The satellites will be reconfigured after the primary mission to serve on the APRS network. As an amateur radio operator, your feedback is important to us. If you have any comments or suggestions involving the FASTRAC satellites, please contact us and they will be seriously considered.
If you have any data for us, you can give us the data by going here and creating an account.

Tracking the Satellites

Once the FASTRAC satellites are in orbit, any amateur radio operator can track and collect data from either satellite using the frequencies in the table below. If data is successfully received by an amateur radio operator, they can upload on the link shared above above so that it can be interpreted and shared with the team. The satellites will be transmitting at approximately 1 W of power. Below are the frequencies used by the satellites.

FASTRAC 1 "Sara Lily" FASTRAC 2 "Emma"
Downlink(1200/9600 Baud) 437.345 MHz FM 145.825 MHz FM
Beacon (1200 Baud) 437.345 MHz AX.25 1200 AFSK 145.825 MHz AX.25 1200 AFSK
Uplink (1200 Baud) 145.980 MHz FM 435.025 MHz FM
Uplink (9600 Baud) 145.825 MHz FM 437.345 MHz FM
Satellite Call Sign FAST1 FAST2

The most updated Two Line Elements of the satellites are given here
After powerup and an initial checkout period, the satellites will start beaconing their telemetry every 3 minutes which is made up of printable ascii characters. When the satellites establish a crosslink with each other, which they will attempt to every 15 minutes, they will exchange gps data to compute a real-time relative navigation solution. For a description of all different data messages on the satellites, please check out the Data User Manual for a detailed description and information on how to decode the messages

Satellite Communication Subsystem Requirements

The FASTRAC satellite communications system must fulfill two primary mission requirements. The first requirement is the transmission of collected data to the network of both university and amateur-run ground stations.
The second requirement is the sharing of GPS data between the two satellites. This is necessary because a big part of the FASTRAC mission is proving that clusters of inexpensive satellites can figure out where they are in relation to each other. This will allow future satellite constellations to actually maintain a desired shape for purposes such as astronomy, radar, or communication.

Satellite Communication Structure

Each FASTRAC satellite is equipped with two Hamtronics receivers and one transmitter. FASTRAC 1 carries two R100 VHF receivers and a single TA451 UHF transmitter. FRASTRAC 2 carries two R451 UHF receivers and one TA51 VHF transmitter.
The VHF/UHF receivers work together to provide uplink and crosslink capabilities. The VHF/UHF transmitters and receivers on both satellites form a duplexing pair that allows the crosslink to take place. The transmitters are also used to relay the stored data to the ground.
The radios on each satellite are connected to a dual port Kantronics KPC9612+ terminal node controller. The TNC will crosslink data at 9600 bps and downlink data at either 1200 bps or 9600 bps, depending on the speed of the uplink connection. The TNC will also beacon its call-sign and telemetry.

FASTRAC Radio Operators

The FASTRAC team is composed almost entirely of engineering undergraduates and graduate students at the University of Texas. Virtually none of us had our amateur radio licenses when we began the design of the FASTRAC satellites. This has changed. The following team members are now part of the amateur radio community.
  • Dr. Glenn Lightsey, KE5DDG
  • Sebastian Munoz, KE5FKV
  • Tena Wang KE5BWD
  • Thomas Campbell KD5TIO
  • Greg Holt KE5BJC
  • Shaun Stewart KD5SZV
  • Emily Burrough KE5BMG
  • Millan Diaz-Aguado KG6MNE
  • Gary Rainey KM5TY (President of UTARC)
  • Phillip Eckhoff KS4JV

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