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ZS6FB > SAT 31.08.03 08:14l 78 Lines 2823 Bytes #999 (0) @ AMSAT
BID : ANS-243.02
Read: DB0FHN GUEST
Subj: VUSat Update
Path: DB0FHN<DB0RGB<DB0MRW<DB0SIF<DB0EA<DB0RES<ON0AR<7M3TJZ<F6CDD<F6KBI<
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Sent: 030831/0655Z @:ZS6FB.MPU.ZAF.AF #:10269 PACTOR-2: XFBB7.04 $:ANS-243.02
From: ZS6FB@ZS6FB.MPU.ZAF.AF
To : SAT@AMSAT
AMSAT News Service Bulletin 243.02 From AMSAT HQ
SILVER SPRING, MD. August 28, 2003
To All RADIO AMATEURS
BID: $ANS-243.02
VUSat is a 40Kg micro-satellite to be launched onboard PSLV(Polar Satellite
Launch Vehicle) from Sriharikota launch range. It will be a co-passenger
along with another remote sensing satellite (most likely IRS-P6) to be
launched on the same vehicle
It is cubical in structure of about 630mm x 630mm x 550mm size.
It has body-mounted solar panels on the four sides. Antennae for
communication are mounted on the top, the bottom portion interfaces with
the launcher.
VUSat is a spinning satellite in a synchronous polar orbit of about 917Km
(LEO)
The bus electronics performs the functions of attitude control, telemetry,
telecommand and data acquisition and is controlled by a single
microprocessor.
Satellite Telecommand(TC) and Telemetry(TM) are on the VHF band
VUSAT PAYLOAD ::
There will be two transponders: Indian and Dutch as main and redundant
systems. Both of them will be operating in Mode-B configuration with
UHF uplink and VHF downlink. This mode is also known as U-V operation.
They are linear transponders designated to operate in CW/USB/FM modes of
amateur communication. Since they are linear transponders they may be tried
in other modes of operation too. They will have an output power of about
30dBm(=1Watt)
They will share common turnstile antennae for input and output along with
satellite mainframe TC/TM systems
Typical link calculations are as below:
1) UHF uplink (435.25MHz centre frequency)
Ground station power : 40dBm (10Watts)
Antenna gain : 12 - 18 dBi
EIRP at max.ant.gain : 56dBm
2)VHF down link (145.90MHz centre frequency)
Antenna gain: 16dBi
Received carrier power(at gnd.RX) : -107dBm(1uV)
Notes: Both the transponders will have 60KHz bandwidth
Transponders may be differentiated by their respective beacons; Indian
transponder will have an unmodulated carrier on 145.940MHz whereas the Dutch
transponder will have modulated information on 145.860MHz
Satellite will have a periodicity of about 7000 secs and is likely to be
visible for about 10-12mins. maximum during a good pass. Like any other LEO
satellite, daily we may expect 3-4 good passes.
Flight versions of The Dutch (by Williams, PE1RAH) and Indian transponders
were tested "on-the-air" on 27 August 2003. Both the transponders worked
satisfactorily in CW/SSB/FM of mode-B (UV) operation. Hams VU2LX, VU2POP,
VU2IR, VU2WMY/URC participated in this important test and gave reports.
With this testing the packages are ready to go on to VUSat deck.
Current news and additional information is available at the AMSAT-India web
site.
http://www.amsat-india.org
[ANS thanks Nagesh, VU2NUD, for the above information]
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