ISSCOM.048 17 April 2005

Soyuz-TMA6

Communications during final phase of approach and docking operation.

On 17.04.05 during the first pass of both objects (ISS and S-TMA6) within range of my position (The Hague) Krikalyov was in contact with TsUP-Moskou via 121.750 mc. A few minutes later these voice communications were also relayed via 143.625 mc.

(This is a heritage of the MIR-era. Then communications from approaching Soyuzy could be received on board of the MIR-station and from there relayed to TsUP-M via geostationary satellites of the Luch-1 type – the Altairs. This possibility became operational in 1991. In this way it was also possible to remain in contact with Soyuzy during return operations even just before the landing. Regretfully no one of the Luch-1 satellites is operational and so the transceiver Lira on board of the Zvezda module cannot be used for that purpose. But everybody can be happy that NASA-facilities like the Ku- and S-bands fill up that gap.)

During this pass of ISS in orbit 36607, 0157-0203UTC (elevation 3 degrees), Krikalyov continuously was reporting the manoeuvres of his ship, which was just passing over Italy. This took place just before sunrise, but Krikalyov did not yet have the ISS in sight. Meanwhile the fly around was finished and the distance to the ISS was still 900 meters. The approach speed was 3 M/sec. A little bit later he could see the ISS on his monitor as well visually. He stated that the sunrise was beautiful. Just before loss of signal of the S-TMA6 the distance was 600 meters , approach speed 2.7 M/sec.

And just like nowadays people interested in spaceflight use to do: I also followed the rest of today’s events via NASA TV.

Before the soft mate with the docking module Pirs, Krikalyov was busy to adjust corrections along the X-axis (roll manoeuvres) to achieve a proper alignment towards the hooks, latches and contacts of the docking mechanism. Even after the first touch (soft mate, kasanye) he still corrected the angle along the X-axis with about 15 degrees. For me this was something new because normally the system Kurs (now also in with success in use) takes care of those corrections. After this the hard mate could be accomplished.

The soft mate took place at 0220UTC.

The original plan was to open the hatches 3 hours after the docking, but TsUP-M decided to do this as early as possible, to enable the S-TMA crew to enter the more spacious ISS. The air seal checks and pressure equalisation lasted relatively long. There was a significant difference between the pressures in the S-TMA and the ISS.

To make good pictures of the entering of the newcomers into the ISS, a direct TV link was needed for which the Russians were responsible. It lasted very long before their infrastructure worked well. The first tracking stations which normally were suitable for that purpose were not used.  

The NASA commentator stated that the hatches were opened at 0445UTC.

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