Phoenix deploys from the ISS on February 19, 2020 at 9:35 UTC

News

http://phxcubesat.asu.edu/content/amateur-operations

Phoenix deploys from the ISS on February 19, 2020 at 9:35 UTC (2:35am MST)! After deployment, it will take some trial and error before we are able to confirm our spacecraft’s TLEs before we can comfortably predict its orbit. The more people who can help us spot our spacecraft, the sooner our operations phase can officially begin! If you would like to help listen for Phoenix, you can do so with the information below.

If you think you’ve heard from Phoenix and you are a member of the SatNOGS network, please publish your observation on the Libre Space community page, and tag @sarah_srogers in the post. Phoenix can be found in the SatNOGS database under #99828 – Phoenix (ASU) 

Alternatively, please complete this google form with your contact information, the lat/long location of the sighting, your waterfall file, and any raw data that you have obtained from the spacecraft!

 

PhxSat Transceiver Characteristics

Hardware Model: GomSpace AX-100

Operating Frequency: 437.35 MHz

Baud rate: 9600 bps

Beacon Interval: 30 seconds

Bandwidth: 20 kHz

Modulation Type: GMSK (Mod Index: 0.5)

Mode: Narrow-FM

Protocol: AX-25 KISS packets with HDLC encapsulation

Encoding: NRZI G3RUH/K9NG scrambled

Spacecraft Callsign: WJ2XOY

IMPORTANT NOTE: Phoenix has a Frequency Buddy

Coincidentally, Phoenix will be broadcasting on the exact same frequency (437.35 MHz) as another CubeSat in a very similar orbit, called QARMAN, which was developed by the von Karman Institute in Belgium. Both satellites also follow the AX.25 protocol at 9600 baud, with GMSK modulation.

To ensure that neither satellite will interrupt communications with each team’s ground station, there will be periods of time when Phoenix’s transmitter is turned OFF and vice versa. Therefore, if you are listening for Phoenix, and do not hear anything, this does not necessarily mean that we have lost communications with the spacecraft. If this does happen, please let us know that you did not hear from Phoenix, so that we may assess whether the transmitter was turned off, or if we need to investigate a separate issue.

More information on QARMAN can be found here

ASU Ground Station Setup (Hardware-Based)

The hardware below will be used at ASU to track and communicate with Phoenix. If you have a hardware-based ground station setup and would like to listen for Phoenix, please ensure you have a similar setup to what is described below.

Radio: Icom IC-9100 (FM Data Mode)

Antenna/Yagi: High gain UHF Yagi/Antenna

Rotator System: Antenna Rotor system to accurately point the antenna to the satellite. The ASU ground station uses the sattrack rotor with P/N: 05194

TNC: Kantronics Packet Communicator 9612 Plus (connected to the radio using the 9600 baud port and set to KISS Mode). The settings file for our TNC can be found here

In addition, GPredict and Hamlib can be used to predict when Phoenix flybys will occur as well as track it while the spacecraft is within range of the Ground Station.

  • GPredict can be downloaded here.
  • You can find hamlib here.

 

Software-Based Ground Station Setup

You can also listen for Phoenix’s packets using an SDR and the following software packages

Software-Based Radios

  • SDR# (software-based radio module ~ compatible with Windows platforms)
  • GQRX (software-based radio module ~ compatible with Linux and Raspberry Pi 3)

Decoding

  • Direwolf (AX.25 packet modem/TNC and APRS encoder/decoder~ compatible with Linux, Mac OSX, and Windows) Direwolf receives input audio from GQRX or SDR# via UDP to display incoming packets.

To use this with SDR#, you will need to download the Audio Stream plugin. More information on the plugin can be found here

For more information on using Direwolf with GQRX, please refer to the GQRX documentation here

 

Sample I/Q and Audio Files

We have recorded I/Q and audio files of a housekeeping packet from Phoenix’s AX100 transceiver as well as the ping command, which can be sent by amateur operators interested in communicating with the spacecraft (see the amateur command list at the bottom of the page). These sample files along with supporting documentation can be found on our public GitHub repo.

https://github.com/ASU-cubesat/phxsat-gsw-public/tree/master/Recordings

 

PhxSat Ground Software for Packet Decoding & Command Uplink

Another way to properly decode the messages that Phoenix is transmitting is to use the ground software developed by the Phoenix team. This is only available for Linux Operating Systems, but it allows the user to monitor incoming packets as well as transmit simple “ping” messages to the spacecraft as a way to encourage amateur participation. Please note that you must be a licensed amateur operator in order to transmit a command to Phoenix. You do not need to be licensed to simply receive telemetry, however. The ground software can be downloaded through the GitHub link below. For instructions on installation and usage, please refer to the README file.

https://github.com/ASU-cubesat/phxsat-gsw-public

Health Beacon Format

Phoenix transmits a distinct health beacon every 30 seconds. This health beacon contains the most vital housekeeping telemetry on the spacecraft to allow mission operators to quickly assess the overall status of the spacecraft. If you capture a message that looks similar to the following format, then you’ve heard from our spacecraft! The health beacon is transmitted in ascii.  

 

Sample health beacon

hk:33,185,7.35,7.5M,3120347795,0.445,0.178,0.154,7.35,161,297,298,0,0,228,0,0

 

Health beacon interpretation

Position   Example Value Interpretation
1 33 Internal Communications Index
2 185 Number of total OBC resets
3 7.35 Current battery voltage
4 7.5M Amount of disk space currently used on the OBC
5 3120347795 Current time of the OBC clock. It is formatted as an RTC (Unix)  timestamp, which is the number of seconds since Jan 01, 1970

Keep in mind that this time is 7 hours ahead of the current time in AZ. Therefore, this should be taken into account before assessing clock drift
6 0.445 Current draw from everything getting 3.3V (in mA)

(Note: This is the nominal voltage draw when the GPS, OBC, and AX100 are all getting power)
7 0.178 Current draw from everything getting 5V (in mA)
8 0.154 Current draw from power switch 7, the switch to the ADCS
9 7.35 Voltage the battery is being charged at via the EPS
10 161 Current the battery is being charged with (in mA)
11 297 EPS temperature (in K)
12 298 Battery temperature (in K)
13 0 Number of Brownouts
14 0 AX-100 Received Signal Strength Index (RSSI)
15 228 AX-100 board temperature
16 0 Number of satellites used in the last GPS solution
17 0 Number of deployed antennas. This will return a value if I2C communication with the antenna is working and deploys the antenna)

 

AX.25 Packet Addressing

If transmitting to the spacecraft, your destination address should be set to the spacecraft’s callsign: WJ2OXY

If you receive Phoenix’s housekeeping telemetry, you should expect to see the following callsigns: KIOO7Y and WJ2OXY

 

Simple Commands for Amateur Participation

In addition to listening for the spacecraft, the team also highly encourages amateur participation. The commands listed below are simple commands that anyone can send to Phoenix and the expected response. Please note that you will need to use our ground software to send the following “ping” command to Phoenix. In addition, you must be a licensed amateur operator to transmit anything to the spacecraft, as mentioned above. A sample I/Q file and a sample audio file of the ping command can be found on our GitHub repo to assist with operations.

 

Name Command Typed Description Expected Response
Ping Command ping 2 Sends a ‘ping’ message to the satellite to ensure it is in range and that you are able to establish two-way communication with the spacecraft “Ping received”

 

TLE Information

Transmission will begin approximately 30 minutes after deployment, once the spacecraft has achieved a relative distance from the other CubeSats being deployed from the ISS.

TLE data can be found using via either of the following resources:

 

Finding Phoenix on CelesTrack:

Following deployment, Phoenix will initially have an International Designator of 1998-067[XX] (the list currently goes up to QY). You can find this TLE data in “the Last 30 Days Launches” first, until such time when we can verify which space object Phoenix is. Please keep in m ind that it can take 2-3 days before data will appear on CelesTrack, but the CelesTrack admins will try to get information as quickly as possible to support operators.

 

Sighting History

Any major updates on Phoenix sightings and relevant TLE information will be posted here to keep anyone interested in tracking Phoenix informed.

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