The flight of Zvezda

Sven Grahn

The launch of Zvezda

The eighth civilian Salyut-class space station 17KSM No. 128-1, the Zvezda  module, was successfully launched on July 12, 2000 at 0456.36 UT. The three stage Krunichev Proton-K rocket reached orbit at 0505 UTC. This was the fifth Proton launch in a month. The initial orbit of Zvezda was 179-333 km at 51.6 degree inclination.

The launch mass of Zvezda was 20295 kg according to Vladimir Agapov. Zvezda is outwardly almost identical to the Mir base block, and its main structure is similar to all the Soviet/Russian civilian orbital stations launched since 1971.

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Tracking Zvezda starting 12 July 2000

In the early morning hours of July12, I checked the Web to see if Zvezda had indeeed been launched. After having noted that the craft was indeeed in orbit I took out my radios and endeavoured to receive signals from Zvezda as it swept over central Europe about 4.5 hours after launch! The map below shows that I was successful.

The signals on 628.0 and 630.0 MHz are similar in character to those in the VHF region and described elsewhere at this web site.
The pictures below show that it is possible to pick up Zvezda with quite minimal gear! The Alinco DJ-X10 scanner is of course a very powerful radio.

I picked up signals from Zvezda on another nine occasions before the day of the docking.
 

Standard UHF-TV antenna used on 628 and 630 MHz
Alinco scanner being charged

Alinco scanner tuned to the upper peaks of the FM telemetry spectra. CW and NFM modes used to hear the signals from Zvezda.
Hand-steering the UHF TV antenna while holding the Alinco scanner in the other hand.

Orbital period during the approach of Zvezda to ISS (Zarya)

The Zvezda to ISS (Zarya) by Zvezda took 12 days. Vladimir Agapov gave the advance information of these maneuvers shown in the table on the right.

He also explained :
"Zvezda is manoeuvring to catch up on Zarya toward an "aiming point" at the 219th orbit of Zvezda over the South Atlantic at 00:13:31 UTC on July 26. At that point, Zvezda should be under Zarya at a relative distance in radial direction no more than 1.5 km and relative velocity along line of sight no more than 5 m/s. Relative distances and velocities in two other directions should be equal to zero.

After that, Zarya is to fly around Zvezda from above (the aiming point) at a distance no closer than 300 meters and get in front of Zvezda for the final phase of docking. So Zarya should be the leading object in orbit at that time. Initial contact (docking) between both modules is now scheduled for 00:54 UTC on July 26." (Actual docking time was 0044 UT)

The figure below shows the orbital period of Zvezda and Zarya resulting from the series of maneuvers that were executed. It turns out that during the final days of the rendezvous, Zarya maneuvered down to meet Zvezda - just as Vladimir explained!
 


 

Picking up ISS (Zarya and Zvezda) after docking

Three hours after the docking I picked up signals from the combined stack of Zarya, Zvezda, and Unity (see table on the right and  map below).

Interestingly, the Zarya signals were stronger than those from Zvezda. The signals from the two parts were not strong at the same time, indicating that the two modules partly block each others signals.


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