Status Report

ISSCOM.005 – ISS Communications – 7 Jan 2001

By SpaceRef Editor
January 7, 2001
Filed under ,

Radio communications :

Radio traffic from inside Zvezda, the Service Module of the ISS, is still a feast for the ears.

As soon as the station passes the Netherlands at the moment of TCA (Time Closest Approach) it comes in reach of the tracking stations Shcholkovo near Moscow and a facility in the neighborhood of Sint Petersburg. Just like the MIR operations, these passes are fully utilized to communicate with Mission Control (TsUP-M).

The downlink channels of the ISS are the VHF-1 143.625 mc and the VHF-2 130.165 mc, as the Russians say UKW-odin (sounds like ádin) and UKW-2 (dwa).

The same practice as during the MIR communications is also the simultaneous use of both frequencies, for instance one for voice and the other for Packet Radio or for voice by another crew member, for instance Shepherd in English. So for those who do not understand Russian a nice challenge.

When the ISS is in range, it is also possible to hear the telemetry transmitter on 628.125 mc (mostly due to the Doppler effect at about 628.093 mc.

The lions’ share in radio traffic is still in Russian, but regularly Shepherd can be heard in contact with his countrymen at TsUP M or via TsUP M with TsUP H (Houston) and of course this is in English.

The 2 Russians, Gidzenko and Krikalyov need the greatest part of their working time for technical activities; they are very skilled cosmonauts, quick boys, who need just half a word and obviously indefatigable. If you understand the Russian language you need all your concentration to understand what it is all about. Problem is that they often use abbreviations. But in fact the base concept of Zvezda is equal to that of MIR (Zvezda was the stand-in base block for MIR-1 and for many years her destination was to become MIR-2) so I know a lot of those abbreviations from my MIR practice.

This is also the case with many systems used to keep the ISS atmosphere livable, like the Elektron (oxygen generator), the Vozdukh (CO-2 scrubber), the KOKh (cooling system) and the KOB (heating circuit).

During this stage (Expedition 1) the coordination about the technical state, maintenance and control mainly takes place between the Russian crew members and Russian experts at TsUP M. In the future this will gradually shift to TsUP H, so Flight control in Houston and to the Marshall Space Flight Centre in Huntsville, where the Flight control for Experiments is located. When during this month the American laboratory module has been integrated in the ISS, the attitude control panel commands of the station will be transferred from the Russian module Zarya to Destiny.

In the first week of the New Year Gidzenko and Krikalyov worked on the preparations for an IVA (so an internal space walk). They tested space suits (air seal, connections, life support systems and communications. As always a difficult job.

During voice communications I had the impression that I was in the MIR scene again.

The plan was to communicate via VHF-2. During the tests emerged the same problem as during MIR EVA’s (and also IVA’s). This is a very strong noise on the downlink of VHF-1 , which makes contact impossible. The noise was caused by cross modulation with an air traffic control frequency (ATC) used in a ATC centre in Western Europe. During the tests by the ISS-crew this noise was much stronger than at the time in MIR.

Krikalyov asked which buttons he had to press for the EVA communications tests: he spoke about “On RTF” and “LIRA/UKW-2”. He asked why he did not had to give the command “Regul”. (Explanation: LIRA is the transceiver on board ISS for communications via the geostationary satellite. On board MIR the same transceiver was the Antares. During EVA-s in MIR this transceiver was also active. There is no geostationary satellite now, but the launch of such a Sputnik Retranslyator -relay satellite- to be positioned over 16 degrees West will be this year).

Shortly we can expect an IVA (Internal Vehicular Activity) for the replacement of the docking cone from the forward docking port of Zvezda to the Nadir port of that module. Possibly we can monitor communications during this EVA via both channels.

These ISSCOM reports are derived from that what I can monitor during the few passes within my range and supported by background knowledge. Of course there must be much more as communications also take place via the ECS (Early Communications System). This is a system to communicate via TDRS-s in the S-band. So for us in Western Europe we cannot monitor this. And the ISS can use the tracking facilities in the U.S.A. during passes there. In the future the ISS can also communicate via American TDRS-s in the KU-bands.

But nevertheless every time listening to the men on board of the ISS is a special event for me: I know them personally from meetings in Moscow (Shepherd and Krikalyov) and in the Netherlands (Krikalyov and Gidzenko). In the website you can find my photographs of an EVA-training by Shepherd and Gidzenko in the training basin in Ts.P.K. Moscow. I also was present during an exercise by Krikalyov (approach and docking training) and during the same training by the ISS crew Dezhurov, Bowersox and Tyurin.

Chris van den Berg, NL-9165/A-UK3202

SpaceRef staff editor.