Outline of JAS-2
- JAS-2 is prepared to succeed the communication of JAS-1b launched in February 1990 and
still working. So JAS-2 is also capable of phone,CW and packet BBS.
These operate in mode J,and users of JAS-1b can make QSO with JAS-2 without changing
Other missions are: the attitude control,digi-talker and test of newly developed
solar cells in space. Testing of solar cell is to be carried out by cooperation with
NASDA,as one of experiments done in the space environment.
- Polar orbit, details have not been fixed yet.
Perigee should be between 800 and 900 km above the ground and we are asking NASDA
to take apogee as high as possible.
- In the middle of August, by H-II rocket No.4, from Tanegashima Space Center of NASDA.
* Mission subsystem (communication subsystem)
- JAS-2 operates in mode J, that is, 145MHz band for uplink and 435MHz band for downlink.
1)Analog transponder (linear transponder) for phone and CW
- uplink 145.90 to 146.00 MHz, 100 kHz pass band
- downlink 435.80 to 435.90 MHz, 100 kHz pass band
- beacon signal at 435.795 MHz, modulated by CW telemetry data
- Total transmitting power is 1W, of which beacon is 100 mW.
2)Digital transponder (store-and-forward packet processor)
- uplink 145.85, .87, .89, .91 MHz, four channels
- downlink 435.91 MHz, one channel
- bit rate 1200 or 9600 bps, alternative operation
- for 1200 bps, uplink in Manchester coded FM / downlink in bi-phase PSK
- for 9600 bps, FSK after G3RUH, both uplink and downlink
- Total transmitting power is 1 W.
3)Digi-talker transmits information by voice, audible with a hand-held transceiver.
Source information data in PCM is sent to JAS-2 from the control station.
4)Data processor, consisting of the CPU V50, static RAMs of 2MB, deals with BBS,
digi-talker, telemetry and command data processing and self-operating jobs.
* Bus subsystem
1)Size and structure
44 cm wide and 47cm high, sphere-like polyhedron consisting of 26 panels,weighs 50 kg.
Gallium-Arsenide solar cells of 2cm x 2cm and 2cm x 1cm pieces, and 11 cells of Nickel
-Cadmium storage battery of 6 AH.
This consists of sun-sensor, geomagnetism sensor, electric magnet or magnetorquer and
The axis of symmetry of JAS-2 becomes the spin axis, and operating attitude will be in
so-called "wheel mode", that is the spin axis being perpendicular to the orbit plane.
* Outer view of JAS-2
* Communication links of JAS-2
* JAS-2 SYSTEM BLOCK DIAGRAM