Encyclopedia Astronautica
Mir EP-4

Crew: Baturin. Member of Russian President's office. Mission to swap Soyuz lifeboats docked to station. Backup crew: Kotov.

Soyuz TM-28 docked at 10:56 GMT on August 15 with the rear (Kvant) port of the Mir space station, which had been vacated at 09:28 GMT on August 12 by Progress M-39. Soyuz TM-27 undocked from Mir at 02:05 GMT on August 25, with Musabayev, Budarin and Baturin aboard. They landed on August 25 at 05:23 UTC near Arkalyk in Kazakstan.

AKA: Altair; Soyuz TM-28 (Baturin).
First Launch: 1998.08.13.
Last Launch: 1998.08.25.
Duration: 11.82 days.

More... - Chronology...

Associated People
  • Baturin Baturin, Yuri Mikhailovich (1949-) Jewish-Russian engineer cosmonaut 1997-2009. Flew on Mir EP-4, ISS EP-1. More...
  • Padalka Padalka, Gennadi Ivanovich (1958-) Russian pilot cosmonaut. Flew on Mir EO-26, ISS EO-9, ISS EO-19. 585 cumulative days in space. More...
  • Bella Bella, Ivan (1964-) Slovak pilot cosmonaut. Flew on Mir Stefanik. First Slovak astronaut. More...
  • Kotov Kotov, Oleg Valeriyevich (1965-) Russian physician cosmonaut. Flew on ISS EO-15, ISS EO-22. MD from Moscow Sergei M. Kirov Military Medicine Academy, 1980 . Russian Air Force. Worked in the TsPK, medical department. Cosmonaut training 3 June 1996 - 18 March 1998. More...

See also
Associated Programs
  • Mir The Mir space station was the last remnant of the once mighty Soviet space programme. It was built to last only five years, and was to have been composed of modules launched by Proton and Buran/Energia launch vehicles. These modules were derived from those originally designed by Chelomei in the 1960's for the Almaz military station programme. As the Soviet Union collapsed Mir stayed in orbit, but the final modules were years late and could only be completed with American financial assistance. Kept flying over a decade beyond its rated life, Mir proved a source of pride to the Russian people and proved the ability of their cosmonauts and engineers to improvise and keep operations going despite all manner of challenges and mishaps. More...

Mir EP-4 Chronology

1998 August 13 - .
  • Mir News 433: Launch of Soyuz-TM28 - . Nation: Russia. Program: Mir. Flight: Mir EP-4; Mir EO-26; Mir EO-25; Mir EO-26/-27. The transport ship Soyuz-TM28 with on board the crew for the 26th Main Expedition to Mir was launched from Baykonur on 13.08.1998 at 09.43.11 UTC. The crew consists of Padalka and Avdeyev. Also on board is the politician Baturin who will make a spaceflight of 12 days. Their call sign is Altair 1, 2 and 3.

    The docking at the aft docking port (+X-axis) of the Mir complex is scheduled for 15.08.1998 at 1037 UTC.


    To free the docking port for the arrival of Soyuz-TM28 the freighter Progress-M39 separated from Mir on 12.08.1998 at 09.28.55 UTC. The autonomous flight of Progress-M39 will last until 29.08.1998 when Progress-M39 has to redock to the then again available docking port.

    Chris v.d. Berg, NL-9165/A-UK3202.

1998 August 13 - . 09:43 GMT - . Launch Site: Baikonur. Launch Complex: Baikonur LC1. LV Family: R-7. Launch Vehicle: Soyuz 11A511U.
  • Soyuz TM-28 - . Call Sign: Altair. Crew: Padalka; Avdeyev; Baturin. Backup Crew: Zalyotin; Kaleri. Payload: Soyuz TM 11F732 s/n 77. Nation: Russia. Related Persons: Padalka; Avdeyev; Baturin; Zalyotin; Kaleri. Agency: RAKA. Manufacturer: Korolev. Program: Mir. Class: Manned. Type: Manned spacecraft. Flight: Mir EP-4; Mir EO-26; Mir EO-25; Mir EO-26/-27. Spacecraft: Soyuz TM. Duration: 198.69 days. Decay Date: 1999-02-28 . USAF Sat Cat: 25429 . COSPAR: 1998-047A. Apogee: 373 km (231 mi). Perigee: 363 km (225 mi). Inclination: 51.7000 deg. Period: 91.90 min. Soyuz TM-28 docked at 10:56 GMT on August 15 with the rear (Kvant) port of the Mir space station, which had been vacated at 09:28 GMT on August 12 by Progress M-39. The EO-25 crew, Musabayev and Budarin, landed with Baturin on Aug 25, leaving the EO-26 crew of Padalka and Avdeyev on the station. As only one final Soyuz mission to Mir was planned, with two of the seats on that Soyuz pre-sold to Slovak and French experimenters, the return crew of Soyuz TM-28 was subject to constant replanning and revision. On February 8, 1999, at 11:23 GMT Padalka and Avdeyev undocked from Mir's -X port in Soyuz TM-28, and redocked at the +X Kvant port at 11:39 GMT, freeing up the front port for the Soyuz TM-29 docking. Finally on February 27, 1999 EO-26 commander Padalka and Slovak cosmonaut Bella undocked Soyuz TM-28 from the Kvant rear docking port at 22:52 GMT, landing in Kazakhstan on February 28 at 02:14 GMT. Avdeyev remained on Mir with the EO-27 crew delivered on Soyuz TM-29, heading for a manned space flight time record.

1998 August 16 - .
  • Mir News 434: Successful docking Soyuz-TM28 - . Nation: Russia. Program: Mir. Flight: Mir EP-4; Mir EO-26; Mir EO-25; Mir EO-26/-27. This transport ship docked at Mir's aft (+X-axis) docking port on 15.08.1998 at 10.56.52 UTC. The intention was to perform approach and docking in the automatic mode with the system Kurs, but at the distance of about 20 M, when the approach speed was almost 0 M/sec. , TsUP seemed to be unsure about the good functioning of the Kurs system and ordered Padalka to take over the approach manually. From the distance of 12 M Padalka flawlessly steered his ship to the docking port and accomplished a perfect docking. Well done for a cosmonaut who makes his first spaceflight. He certainly deserves the so called 'manual docking bonus'.

    During the pass in the next orbit (71335, 1218-1229 UTC) the crew prepared the TV-report of the opening of the hatches and the meeting of the 2 crews. It could be derived from the given communication commands that the images of that event would be transmitted on a UHF-channel and via Russian tracking stations, so not via Altair-2. Just before the complex disappeared behind my eastern horizon the crews got permission to open the hatches and to greet each other. This time the Russians refrained from the normal routine to have the first human contact between the 2 commanders due to the presence of the VIP Baturin. He got the honour to be the first crew member to float from Soyuz-TM28 into Mir and embrace his CIS-countryman, Musabayev. This took place at 1230 UTC.

    From that moment on the crew of the Mir-space station consists of 5 persons and this will undoubtedly draw a heavy toil on the life support systems of the complex. Technically the situation on board was not 100% before the docking: the power supply is not fully restored and the station seems to fly in the free drift (they spoke about 'indikatornyy rezhim', but whether the gyrodynes are fully spinning or not has not been confirmed) and Musabayev got orders to economise power consumption and to switch off all superfluous equipment.

    Until his departure Musabayev will remain commander of both crews. During all communication sessions on 15.08.1998 it was clear that Musabayev acquits himself of that task. Meanwhile Budarin occupied himself with radio-amateurism on 145.985 mc. He tried to get in touch with Russian radio-amateurs.

    During the last pass in which Mir was able to communicate via a Russian tracking station with TsUP (orb. 71339, 1704-1715 UTC) Musabayev called in vain and he decided to give his message blindly (hoping that TsUP would hear him anyway). He reported that they had reinstalled Baturin's seat liner (from Soyuz-TM28 to Soyuz-TM27). The BKV-3 (a.c.) worked after he had tried to switch it on 3 times. The humidity was quoted as 11.3, the gas composition in the station as: CO2 4.5 , oxygen 203 and water 11.2. Pressure 797 MM.

    Communications during flight Soyuz-TM28:

    13.08.1998: After the launch the signals of the Soyuz-TM28 could be monitored here for the first time between 1415-1420 UTC. A very stable Padalka reported the results of the 1st and 2nd impulses: 1st 1384 during 32 seconds, 2nd 696 for 16 seconds. The SIRT (system for the measurement of the fuel consumption) gave after the 1st impulse 745 KG, after the 2nd one 728 KG (remaining fuel). During the following passes he reported that all went well, they were in a good mood and health and all systems worked nominally. There were only problems with a recording experiment. The device of that experiment did not give the right figures. Baturin had been shooting video images. Good signals in the 166 and 165 mc bands and on 922.755 mc.

    During the pass between 1547 and 1552 UTC again good signals on all frequencies. TCA (dip in 922.755 mc signal) was at 154915 UTC. Padalka still very stable reported the good functioning of all systems. They had done something with the orientation in relation to the power supply and they got a good power reading between 25 and 26. The TV-test they had done was positive. They felt well and enjoyed the flight.

    14.08.1998: Good signals on all frequencies and Padalka again sounded like a skilled cosmonaut. All parameters were normal and the only problem was a recording device about which Padalka long and extensively reported.

    Soyuz-TM27: The return flight of the crew of the 25th Main Expedition to Mir (Musabayev and Budarin) and the cosmonaut-researcher-politician Baturin is scheduled for 25.08.1998. The Soyuz-TM27 will undock from Mir at 0220 UTC descend was announced as 0526 UTC.

    26th Main Expedition to Mir: The crew of this ME is Padalka and Avdeyev. According to information now available (confirmed by a reliable source) this crew will remain on board Mir until June 1999. So if there will be no changes anymore the 26th ME is the last one to Mir.


    In the period after MirNEWS.432 a number of technical problems emerged. Radio communications revealed that the complex had been flying in free drift (indikatornyy rezhim), which caused a sharp decrease in power supply on 11.08.1998. That day all superfluous systems had to be switched off and for a while only 2 lamps were burning: one in the Base Block and one near the P.Kh.O. (transition section). There were also airseal problems. Musabayev had to check a rubber bearing of a hatch with his fingers. To secure a good atmosphere on board the crew used oxygen from a tank in the Progress-M39. The crew also repeatedly tested the Kurs antenna on Kvant-1 and they had to change cable connections of this system. Not long before the launch of Soyuz-TM28 they had to repeat such a test which seemed to have been positive.

    On 12.08.1998 Musabayev launched a long tirade in which he relieved his feelings. He has great problems with the activities of journalists who, in his opinion, are not really interested in the cosmonauts as such. Only when something goes wrong they are on it like a bird and then they blame the crew for that. He characterises a lot of their publications as nonsense and even swinishness. He emphasises that this expedition, the 25th, was a very fruitful one. While the Mir-station is operational for 12.5 years their expedition performed 50% of all melting experiments in the furnaces, for instance almost all what had to be done with the Optizon furnace. They accomplished experiments which could not be done by previous expeditions. In the 190 days of their mission they were not able to work according the formular 23 for 2 days and for this the crew was even not to blame. They also solved a lot of technical problems and he refers to the repair of the SUD (attitude control system) on the eve of the arrival of a Shuttle.

    The fact that life on board Mir is still possible is thanks to their work for they installed the new VDU (external thruster). They did a lot of cardio vascular experiments, which still had to be executed.

    My personal opinion about this argumentation is the following: I do not want to compare this expedition with other ones. But I agree with Musabayev: he was in command of a magnificent expedition.

    First day with 2 crews on board:

    On 16.08.1998 during the first pass Padalka asked TsUP whether they had seen something in the Telemetry and he supposed that they wished to speak to them. TsUP confirmed this and ordered Padalka to switch over to the 2nd regime for this conversation. From this moment on monitoring had no sense due the computerised scrambling of the speech. For a very long time, I dare to say for years, they had not used this routine.

    Chris v.d. Berg, NL-9165/A-UK3202.

1998 August 25 - .
  • Mir News 435: Soyuz-TM27 safely landed - . Nation: Russia. Program: Mir. Flight: Mir EP-4; Mir EO-26; Mir EO-25; Mir EO-26/-27. Soyuz-TM27 with on board the relieved ME 25 crew and the politician Baturin undocked from Mir on 25.08.98 at 0205 UTC and after a short autonomous flight the landing capsule (SA) made a safe landing at a distance of 40 KM from the city Dzhezkazgan in Kazakhstan at 05.22.44 UTC. The flight and the descent took place without problems. This mission lasted for Musabayev and Budarin 207 days, for Baturin 12.

    Communications during the autonomous flight. For these communications tracking stations in Russia were in use. I did not monitor traffic via the geostationary satellite Altair-2. There has been reported that at least one session via an SR was scheduled and also that between 0435-0531 UTC this relay was in use and during the final phase of the descent this took place parallel with direct communications via tracking stations. My calculations for traffic via Mir and Altair-2 gave the window 0416-0510 UTC so possibly the window between 0435-0531 UTC was for another SR. I thought about the Luch-1 (1995-054A - 23681) over 76 degrees East, but in my opinion this SR ceased transmissions long ago. However its expected operational life was estimated to be 5 years.


    This transport ship is still docked at the aft (Kvant-1) docking port. In fact this ship also has to serve as a life boat. So if emergency forces the crew to leave the complex in a hurry they have to board Soyuz-TM as quick as possible. That is why the Soyuz-TM has to be redocked from the aft to the forward (P.Kh.O. - transition section) -X axis port. This operation during which Padalka and Avdeyev will be on board of the Soyuz-TM28 is scheduled for 27.08.1998 between 0544-0608 UTC. This will be during Mir's orbit nr. 71520, 0559-0602 UTC. Regretfully the elevation for observers in Western Europe will be very low 0 - 1 degree.


    This freighter is still flying some hundred kilometres in front of Mir. The plan is to redock this freighter at the aft (Kvant-1) +X axis port on 29.08.1998. Progress-M39 has to remain docked at that port until the arrival of the next freighter. It will last a long time before this freighter will be launched and it might even be possible that this launch will not take place due to the lack of funding. The Progress-M39 makes the thermo regulation of the Kvant-1 module easier and protects the aft docking port against extreme temperatures. Meanwhile the space still available in the cargo compartment of the Progress-M39 can be used for the disposal of garbage and no longer needed equipment.


    During the last 10 days in which Mir had 2 crews on board they had to work regularly on the life systems. There were problems with the CO2 scrubber Vozdukh in the Base Block. After some repair attempts they had to use spare parts from the Vozdukh in the Kvant-1 module. Especially Musabayev and Budarin had to use every effort for apart from working on the life supporting systems they had to prepare themselves for the return flight. They started to load that what they had to bring with them to earth one day before their departure. It lasted also long before they started their exercises in the Chibis, a pressure suit to give the blood circulation the impression of earthly gravity.

    Musabayev told TsUP that there was only little room on board of their ship. So he asked TsUP to restrict their luggage to the necessary items and to leave all what might be superfluous on board Mir. He also proposed to put samples of experiments, cassettes and disks in the container without extra packing. TsUP partly granted this idea. During the last days Baturin could be heard discussing his experiments. He spoke about Intrazvuk, Phantom and Interior. I did not hear much of Avdeyev. Perhaps he was too busy to get accustomed with the present state of the station and equipment. As of today (25.08) Padalka is commander of the Mir station. During the last days he sometimes assisted Musabayev in this field.

    2nd Regime:

    This computer scrambled system for speech about which I reported in my MINEWS.434 was rarely in use during the last days.

    Chris v.d. Berg, NL-9165/A-UK3202.

1998 August 25 - .
Home - Browse - Contact
© / Conditions for Use