THYBOLT MISSION FOR HAMS

Dhruva Space's Thybolt Mission launched Thybolt-1 and Thybolt-2 satellites using the Space-qualified 1U Dhruva Space Satellite Orbital Deployer (DSOD-1U).

These nanosatellites are built on the 0.5U P-DoT satellite platform which is designed, built and tested by Dhruva Space for use in the amateur communications, disaster management, and low bit-rate applications of STEM and strategic importance. The qualification of this 0.5U platform with its sub-systems will enable many more amateurs across India to learn, build, launch and operate experiments on amateur satellite missions.

Primary Objective : Qualification of Satellite Platform and validated by successful telemetry reception
Secondary Objective: Successful store and forward amateur operations

Mission profile

Launch Vehicle : PSLV C54
Orbit : Near circular polar sun synchronous orbit at 511 km
Inclination  : 97.45 degrees
Transmissions :  Telemetry, Beacon
Reception: Telecommand, Store-and-Forward Message

Beacon

Beacon on Thybolt satellite transmits Morse Code at 25 WPM. The Morse will send ASCII characters that can be decoded using the below digital code table to obtain Satellite’s state:

Following are the radio parameters to receive the Beacon data from either of the Thybolt satellites:

Frequency: 435.360 MHz
Modulation: OOK/CW
Morse Speed: 25 WPM
Bandwidth: 1 kHz

Digital
Code
Morse
Characters
Beacon
counter
OBC msg
counter
Battery
Voltage
OBC Mode
Battery
Temp(C)
GPS
Status
TTC last
Received
Command
Types
Beacon
Rate
Beacon
Status
0
E: .
Counter value increases between E to M and rolls back to E to indicate a new beacon everytime
Counter value increases with every OBC message successfully decoded. Value increases fromE to M and rolls back to E
<3.5
Power Saving Mode
<0
On
Good
Short
Off
1
T: -
3.5-3.7
Nominal Mode
0 to 20
OFF
Working
Long
On
2
I: ..
3.7-4.0
Safe Mode
20 to 30
Standby
Critical
3
A: .-
>4.0
Detumbling
30 to 40
4
N: -.
Sun acquisition
>40
5
S: ...
EoL
6
M: --

Sample Packet Frame

Header
Beacon
counter
On-Board Computer
msg counter
Battery
Voltage
On-Board
Computer
Mode
Battery
Temp(C)
GPS
Status
TTC last
Received
Command
Types
Beacon
Rate
Beacon
Status
(THY01) - .... -.-- ----- .----
.
.
..
-
..
.
-
.
-
THY** ** - 01 or 02
E
E
I
T
I
E
T
E
T

On successful reception of three or more consecutive beacon transmissions of the satellite, consider your ground setup to be capable of receiving Thybolt satellite beacons and deserving of a memento of the contact established.

Enthusiasts can apply for receiving a QSL card by filling in their station information and other specifics in the below form: 

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Telemetry

The Telemetry from Thybolt satellites are encoded in CCSDS frame format. Upon demodulating the signal, operators will be able to view the sync word ‘PDOT’ followed by the CCSDS frame as mentioned in the Decoding sequence table below.

Upon decoding three or more packets, operators can send the full data along with sync below in the below form to confirm successful telemetry reception via a QSL card.

To help amateur radio operators receive Thybolt satellites signals, we have provided an open-source GNURadio OOT block and receiver flow graph information that can help demodulate and decode telemetry data using an SDR. Links to GNURadio OOT Block and flowgraph along with online decoder software are provided below.

Link to gr-thybolt : https://github.com/thybolt4hams/gr-thybolt
Link to online decoder software : thyboltmission.web.app

Following are the radio parameters to receive the telemetry packets from either of the Thybolt satellites:

Frequency: 436.175 MHz
Area of operation: India
Modulation:
2FSK
Baud Rate: 4800
Sync Word: AAAAAAAAAAAAAAAA
Preamble: D42D50444F54
* Preamble and Sync Word above are mentioned in hexadecimal 

Decoding Sequence
Sync Word <AAAAAAAAAAAAAAAA> + Preamble <D42D50444F54> + CCSDS packet frame (510 Bytes) ->
CCSDS Decoding ->
Telemetry Data
* <Hex Value is mentioned in angled brackets>

For any assistance in relation to decoding of telemetry data, please reach out to thybolt4hams@dhruvaspace.com.

Upon successful reception of three or more consecutive TM transmissions of the satellite, consider your ground setup to be capable of receiving Thybolt satellite Telemetry Data and deserving of a memento of the contact established.

Enthusiasts can apply for receiving a QSL card by filling in their station information and other specifics in the below form: 

Thank you! Your submission has been received!
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Store-and-Forward messaging

The primary payload of Thybolt satellites is an application to receive, store and forward user text messages. Amateur operators can send to the satellite, custom messages limited to 26 letters prefixed with six-letter amateur call signs. These messages will be downloaded at a ground station through Dhruva Space operator commands. The user messages will be then displayed on a website along with received signal strength on the satellite.

A tool to generate raw command bytes to be sent through an FSK modulator in GNURadio is available on Thybolt mission website mentioned below. User can input a user message in the tool and click the Load TC button to get the encrypted raw hexadecimal data in binary format to be sent to the digital radio. User can further download the binary data as a text file and add it in GNURadio.

TC Generator Website : https://thyboltmission.web.app/storeandforward

Following are the radio frequency parameters to send store-and-forward messages to either of the Thybolt satellites:

Frequency: 435.400 MHz
Modulation:
2FSK
BaudRate:
1200
Area of operation: India
Frequency Deviation:
6 kHz

On successfully uploading a store-and-forward message to the satellite, please fill up the following form to request for a QSL card:

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Chief Patrons

Star Fleet Amateur Radio Club (VU2ISL)
Sanjay Nekkanti (VU3ISS)
Krishna Teja Penamakuru (VU3ECT)
Abhay Egoor (VU3ECX)
Jyothir Adithya Rao (VU3ECS)
Deepak Kishanrao Inde (VU2EKV)

National Institute of Amateur Radio (VU2NRO)
Ram Mohan Suri (VU2MYH)

SSM College of Engineering (VU2SYE)
J. Jaganpradeep
Indian Academy of Communication and Disaster Management (VU2MQT)
Rinku Nag Biswas (VU2JFB)

West Bengal  Radio Club (VU2WB)
Ambarish Nag Biswas (VU2JFA)

Aniruddha's Academy of Disaster Management
Mahesh R. Atale (VU2XFE)

Indian Institute of Hams (VU2FI)
Dr. S. Satyapal (VU2FI)

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