SPACEDOS01B - Flight Model
Applications
- Space Dosimetry and spectrometry for unmanned missions
- TLR9 space dosimetry instrument - flight heritage: Sokrat-R (NORAD ID 44404) satellite
- Real-time determination of the absorbed dose in silicon and dose equivalent
- To study the material shielding
- Space Radiation Research
- Determine the LET energy spectrum of the cosmic particles
- Measure the time evolution of the radiation flux
- Operated on board of CubeSat
Main technical parameters
- Deposited Energy range: from 100 keV to 9 MeV, optionally extended to range from 200 keV to 12 MeV (divided into eight logarithmic channels)
- Measurement environment: vacuum < 3.2×10^-2 Pa
- Energy Resolution: < 50 keV/channel
- Particle types: electrons, protons, heavy ions
- Integration Time: 15 s
- Power supply: 3.3 V / 3 mA (Typical consumption: 2.6 mA @ 3.3 V)
- Interface: UART (RS232) TTL
- Temperature Stability: from -50 ℃ to +50 ℃ within error of +50 keV
- Used Sensor: HAMAMATSU S11773-02 (PIN diode 5 x 5 x 0.5 mm)
- The default configuration has a detection volume of 12.5 mm³
- H x W x L: 15mm x 41mm x 94 mm
- Weight: 33 g
Physical dimensions
Electrical interface
The connector is a 2.54mm pitch pin header.
| Signal | Description |
|---|---|
| PD2 | Universal Input pin |
| PD3 | Universal Output pin |
| RX0 | RS232 Receive (3.3 V) |
| TX0 | RS232 Transmit (3.3 V) |
| RST# | Reset (through capacitor) |
| GND | Ground |
| 3V3 | Power supply +3.3 V |
Electromagnetic Compatibility according to ECSS-E-ST-20-07C Rev.2
Communication protocol
Sample of output data
$POSD,2a1c18d43c3937e40a3beb6c2855589b2d1a19e9
$ICSD
$DPSD,98,7fbd,36,1,0,0,0,0,0,0,100
$HKSD,9,98,800b,fe,0,0,7fbd,36,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
$BESD,4,e7,2,1,0,0,0,0,0
$ADSD,d3,3,0,0,0,0
SPACEDOS sends $DPSD, $HKSD, and $BESD messages each cca 15 seconds. The $ADSD message is sent once per day.
Communication speed is 2400 baud.
Power On
It transmits just after the power is on.
#POSD, <git hash>
This information says hello after turning the power on.
Initiation complete
Transmitted once after initialization, after powering on.
#ICSD
Initiation of the SPACEDOS HW is done. Initiation is completed up to one second after the power is on.
DPSD - SpaceDos Data Payload message
Transmitted every 15 seconds.
$DPSD, <uptime>, <noise channel>, <0.1 MeV>, <0.14 MeV>, <0.21 MeV>, <0.33 MeV>, <0.66 MeV>, <1.68 MeV>, <4.72 MeV>, <'>=9 MeV'>, <DC offset>
| Value | Length | Type | Note |
|---|---|---|---|
| $DPSD | 5 B | Char | Header |
| uptime | 4 B | Hex | Time from power on |
| noise channel | 2 B | Hex | This channel contains noise |
| 0.1 MeV | 2 B | Hex | Number of particles with absorbed energy above 0.1 MeV |
| … | … | … | |
| ’>=9’ MeV | 2 B | Hex | Overrange particles |
| DC offset | 2 B | Hex | Offset of ADC |
These messages should be stored for a long time and transmitted to the ground as a batch.
Minimal data payload (without time mark) is 18 B per 15 s => 103680 B per day
HKSD - SpaceDos HouseKeeping message
Transmitted every 15 seconds.
$HKSD, <measurement No.> , <uptime>, <filter suppressions>, <position of the 1-st channel>, <1-st ch.>, <2-nd ch.>, <3-rd ch.>,...
This is a packet with housekeeping information. Transmission of this packet is done besides other experiments’ housekeeping data. The total length of this packet should be shortened.
| Value | Range | type | Note |
|---|---|---|---|
| $HKSD | fix | Char | Header |
| measurement No. | 0..65535 | Hex | |
| uptime | 0..4294967295 | Hex | |
| filter suppressions | 0..65535 | Hex | Number of usage of digital filter for double peak suppression |
| position of the 1-st channel | 0..511 | Hex | |
| 1-st ch. | 0..65535 | Hex | Number of events in 1-st ch. |
| 2-nd ch. | 0..65535 | Hex | Number of events in 2-nd ch. |
| … | … | ||
| 50-th ch. | 0..65535 | Hex | Number of events in 50-th ch. |
BESD - SpaceDos BEacon message
Transmitted every 15 seconds. Values are zeroed after sending an ADSD message.
$BESD,<counter>, <0.1 MeV>, <0.14 MeV>, <0.21 MeV>, <0.33 MeV>, <0.66 MeV>, <1.68 MeV>, <4.72 MeV>, <'>=9 MeV'>
This message contains cumulative data for beacon transmission.
| Value | Length | Type | Note |
|---|---|---|---|
| $BESD | 5 B | Char | Header |
| counter | 2 B | Hex | Number of the beacon message |
| 0.1 MeV | 2 B | Hex | Number of particles with absorbed energy above 0.1 MeV |
| 0.14 MeV | 2 B | Hex | Number of particles with absorbed energy above 0.14 MeV |
| … | … | … | |
| ’>=9’ MeV | 2 B | Hex | Overrange particles |
ADSD - SpaceDos Almanac Data message
Transmitted after 5760 beacon messages. (approximately once a day)
$ADSD, <0.1 MeV 1 day old>, <0.14 MeV one day old>, <0.66 MeV one day old>, <0.1 MeV two days old>, <0.14 MeV two days old>, <0.66 MeV two days old>
This message contains two days of old data for beacon transmission purposes.
| Value | Length | Type | Note |
|---|---|---|---|
| $ADSD | 5 B | Char | Header |
| 0.1 MeV one day old | 4 B | Hex | Number of particles with absorbed energy above 0.1 MeV one day before |
| 0.14 MeV one day old | 4 B | Hex | Number of particles with absorbed energy above 0.14 MeV one day before |
| 0.66 MeV one day old | 4 B | Hex | Number of particles with absorbed energy above 0.66 MeV one day before |
| 0.1 MeV two days old | 4 B | Hex | Number of particles with absorbed energy above 0.1 MeV two days before |
| 0.14 MeV two days old | 4 B | Hex | Number of particles with absorbed energy above 0.14 MeV two days before |
| 0.66 MeV two days old | 4 B | Hex | Number of particles with absorbed energy above 0.66 MeV two days before |