RadioAstron Monthly Notices
Tasks and developments completed in the ASC
1. Monitoring of the development of the on-board 92-cm receiver (R-SRT-92 cm) ongoing at the KB GORIZONT in Nizhnii Novgorod:
a) assembling and tuning of printing-circuit boards for the Test-set device and assembling of the Test-set device itself;
b) assembling of printing-circuit boards for the Flight Model of the receiver.
2. Monitoring of the development of the on-board 1.35-cm receiver (R-SRT-1.35 cm) ongoing at the OKB IRE in Fryazino:
a) Technical specifications on Power Supply Unit for the receiver were agreed and proved;
b) Development of formal technical documentation on the receiver was continuing;
c) Foreign components used in the receiver design were certificated;
d) The program and the methods of the receiver tests were written and agreed.
3. Engineering models of the On-board Rubidium Frequency Standard (ORFS-SRT) and Space Radio Telescope On-board Heterodyne and Clock Frequencies Synthesizer set (OHCFS-SRT) were packed and delivered to LA to be assembled with the SRT in the Device Container.
4. Hardware and software for the automatic time synchronization of the equipment used in Zero Baseline Interferometer Tests (ZBIT) was developed and tested.
5. Laboratory measurements of phase variations in the OHCFS were conducted. Two type of the phase loop lock module were tested on time scale of several hours. The study is being continued.
6. Ground-based H-maser standard was put in operation and tested at the Pushchino Radio Astronomical Observatory in order to use it in the future RadioAstron tests.
7. In compliance with Formatter EGSE (Electronic Ground Support Equipment) development program two control desks for Formatter test fixture were finished and tested including applied soft debugging. The desks control Formatter operating mode, supply the simulation sets of SRT telemetry data for Formatter frame header, display power supply and Formatter current mode parameters, including internal blocks temperatures. The controlling and data representation are realized by PC display and keyboard. The soft provides USB PC-desk data interchange and display.
8. Postprocessing of VLBA observations of H2O maser source W3(OH) has been completed. The data were taken from the VLBA archive. It was found that the brightest feature in the spectrum with the flux density about 3000 Jy was not resolved at the longest baseline of 640 Mλ (0.3 mas). The source can be the target for RdioAstron (astro-ph/0305455).
Tasks and developments completed in Lavochkin Association
9. All engineering devices belonging to Focal Container (FC) passed reception check and were assembled at the standard frame of Focal Container.
10. Thermo-Vacuum-Test (TVT) of Device Container (DC), equipped with the thermal models of scientific payload and assembled with the Thermo-Vacuum Model (TVM) of the Spacecraft Bus, is close to accomplishment.
11. Thermal tests of special cryogenic system which will be used for LNA cooling during Pushchino test were successfully completed. The technique of drying the cryogenic system and the technique of safe cooling process at a low rate of 25-30 degrees per hour were developed as the output of the tests.
Appendix - the list of used acronyms
ASC Astro Space Center of Lebedev Physical Institute
Cold Plate cooled LNAs and antenna feed
DC hermetic device container (part of payload); it contains Formatter, Rb oscillators, synthesizer, control unit and is placed under dish
DM Device Module = DC + H-maser
EGSE Electronic Ground Support Equipment
Electronic Complex - all SRT electronics
EM Engineering Model
FC Focal Container – hermetic package with the scientific payload; it contains receivers,
microwave synthesizer, control unit and is placed in focal site of dish
FM Focal Module = Focal Container+Cold Plate
LA Lavochkin Association
OHCFS-SRT Space Radio Telescope On-board Heterodyne and Clock Frequency Synthesizer set
OHFS-SRT Space Radio Telescope On-board Hydrogen Frequency Standard
ORFS-SRT Space Radio Telescope On-board Rubidium Frequency Standard
- Service Module, Spacecraft bus – spacecraft itself (without payload).
SRT Space Radio Telescope (all scientific payload including 10-m dish)
TMS Spacecraft Telemetry System (technical)
TVT Thermo-Vacuum Tests
VIRK Scientific high rate (up to 2x72 Mbit/s) radio complex, including transponder
ZBIT Zero Baseline Interferometer Tests (ZBIT)