The TKS ferry for the Almaz Space Station

Sven Grahn

TKS - the Transport Ship

The TKS was developed as a transport ship for the full-scale Almaz military space station envisaged by OKB-52 general designer Vladimir Chelomey. Its development was approved in June 1970 (1). It was intended to be able to deliver and return crews and cargo, rasie the orbit of Almaz, and control the attitude of the Almaz complex.

The TKS consisted of two major parts: The return apparatus (VA) and the Functional Cargo Block (FGB). The FGB had two diameters, just like Almaz; 2.9 meters and 4.15 meters. However, only a small portion of the length, near the launch vehicle interface had the the wide diameter. The rest of the craft used the smaller diameter. The VA was mounted on the front end of the  2.9 meter section of the hull. Two large rocket engines were placed on each side of the hull  at the front of the FGB with their thrust pointing forward. The thrust of each engine was 4385 N. Cylindrical tanks on the outside of the 2.9 meter section of the hull provided 3822 kg of propellant for these engines (1).

In development of TKS the central office of OKB-52 (now NPO Mashinostroyeniya) was responsible for the VA recovery capsule, while its Branch #1in Fili (now known as KB Salyut and part of the Khrunichev enterprise) was responsible for the baseline TKS and its FGB service systems.

TKS descent vehicle - VA

The return apparatus (VA) for both the station and the TKS had an access hatch through the heat shield. The  VA shape was quite similar to that of the Apollo CSM. The size of the VA upon touchdown was 3.05 m at the base of the 2.06 m high truncated cone that formed the VA (2). At launch and in orbit there was a double cone tower-shaped structure on top of the landing capsule. The upper part of this tower contained launch escape rcokets and retro rockets for descent. The lower part probably contained the parachute and other equipment.

The VA was capable of 31 hours of autonomous flight (1), but according to the Russian sketch below the normal procedure was for the VA two fly for two orbits separate from the Almaz base block or the TKS. The figure below shows how the VA would be oriented for retro fire and that some kind of equipment pod at the base of the capsule was separated after retrofire. A lifting re-entry was the normal descent mode, but if that failed the capsule would be spin-stabilised and re-enter ballistically. After re-entry, the cone on top of the landing capsule detached. Some kind of simple altimeter (probably using the same gamma-ray detector that is used on Soyuz) triggered retrorockets in the upper part of the capsule to achieve a soft landing. A touchdown on ground or in water was possible. At landing the capsule weighed 3800 kg (1).

TKS-related flights

Six TKS vehicles were manufactured. Their unmanned test flights began as late as in the summer of 1977 (Kosmos-929). Before that a series of recovery vehicle tests was initiated. In 1976-1979 four pairs of VAs were launched by UR-500K to test launch escape system and technique of deorbiting and landing of VA (three pairs were orbited as Kosmos-881,-882; Kosmos-997,-998 and Kosmos-1100,-1101, one pair failed to orbit due to Proton launch vehicle failure);

In 1977-1984 four TKS vehicles were launched

In the table below, all flights with some heritage to the TKS has been listed. This includes both VA test flights with a TKS mock-up, TKS flights with VA crew return vehicles, flights with the service module of the TKS the FGB functioning as an add-on module to Salyut-7, Mir and ISS as well as the flights when a stripped down FGB, known as the FSB was used as a "space tug" for Kvant and Polyus. In this article only the proper TKS flights will be described.
Designation  Launch date Name  Remarks
TKS Mockup 1976 Dec 15 With Kosmos-881/882, LVI-1 VAs: 009A/1 and 009/1
TKS No. 161-01 1977 July 17 Kosmos-929 TKS test flight, VA no. 009A/2
TKS Mockup 1977 Aug 5 LVI-2 Launch failure  VAs: 009A/P and 009/P
TKS Mockup 1978 Mar 30 With Kosmos-997/998, LVI-3 VAs: 009A/P2 and 009P/2 (identical to 009A/2) 
TKS Mockup 1979 May 22 With Kosmos-1100/1101, LVI-4 VAs: 0102A and 0102, destroyed on landing 
TKS No. 163-01 1981 Apr 25 Kosmos-1267 Docked with Salyut-6, VA 0103/3
TKS No. 164-01 1983 Mar  2 Kosmos-1443 Docked with Salyut-7, VA 0103/1
TKS-M No. 165-01 1985 Sep 27 Kosmos-1686 Docked with Salyut-7, no VA
FSB No. 166-01 1987 Mar 31 Propulsion unit for Kvant  
FSB No. 162-01 1987 May 15 Propulsion unit for Polyus  
TsM-D No. 171-01 1989 Nov 26 Kvant-2 Docked with Mir
TsM-T No. 172-01 1990 May 31 Kristall Docked with Mir
TsM-O No. 173-01 1995 May 20 Spektr Docked with Mir
TsM-I No. 174-01 1996 Apr 23 Priroda Docked with Mir
FGB  No. 175-01 1998 Nov 20 Zarya ISS first element
USM  No. 176-01     Under construction as ISS docking module

The flight of Kosmos-929

The Kettering Group was extremely successful in tracking Kosmos-929. Below is an excerpt from Geoff Perry's "day-to-day log" for 17 July 1977. Geoff Perry spent the holiday in his caravan at at caravan park near Bude, Cornwall.

"... it was high tide and the force 7-8 gale and some waves were washing right over the breakwater...we returned to the van via Crooklets [beach] for an early night. But it was not to be! On arriving back Susan Colwill [the operator of the caravan park] brought me a telephone message from David Muggleton which had arrived shortly before. It said: SALYUT 19.950 APPROX. AOS 1030 1200 1330 CA 1507 RAPID DOPPLER CA 1640 RAPID DOPPLER AOS 1809 DAVID. Now what was all this about? If GMT, these times did not fit Salyut 5. .... I listened to Radio Moscow at 2000 Z and right at the end they announced Cosmos 929  but without heights......"

Yes, David Muggleton had indeed picked up Kosmos-929, which had been launched at 0900 UT, i.e. David picked up the craft one orbit after launch on the first pass over Russia. Incredible!

It later turned out that the frequency was 19.954 MHz and that there were two independent telemetry transmitter, but telemetry values in the two systems were quite similar. The most significant change was in word 14 of the 15-word telemetry frame. Word 3  and 4 in the two formats changed in the same manner. The change in frequency took place at exactly 30 minute intervals. The two format could be distinguished by the number of synchronization pulses in the frame. One had 29 pulses and the other had 30 synchronization pulses. (Read more here about the TKS shortwave telemetry systems).

A day after launch I also detected strong PPM-AM telemetry on 166.0 MHz similar to that received from Soyuz spacecraft at the time. Interestingly the 166 MHz signals were very strong but always quite brief, only 1-2 minutes each time. This was caused by the transmitter being turned on quite far to the east, just before setting below my horizon. This could of course mean that the command station for this transmitter was quite far to the east. The figure on the right points to Tblisi being the command station. Signals on this frequency were very consistent during the first month. We certainly realized that something radical happened in mid August. The PPM-AM signals on 166.0 MHz ceased sometime between 16 August and 20 August. On 18 August, Geoff Perry wrote in his day-to-day log:

".....Alarm clock set so I could monitor C.929 on rev 513 at 0239 Z. Seemed to be a bit late. Has it been raised?..."
The orbit was indeed raised on 17 August and we now know that the VA capsule was recovered at   ... on .... . Therefore the signals on 166.0 MHz were clearly related to the recovery of the VA. So, supposedly this transmitter relayed the status of the VA. This frequency was never used again on TKS flights. But, we now know that Kosmos-929 was the only fully equipped TKS capable of carrying a crew.

The Kettering Group was indeed baffled by this flight. This is what I wrote in a note to Richard Flagg dated 10 September 1977:

"....we have had deep mysteries before. Remember how baffled we were over the Salyut-2/Cosmos-557 relationship? Eventually we will solve this riddle also......"
Of course, four years later we discovered that Kosmos-929 also transmitted on 247 MHz, a characteristic of all TKS-type flights. We made this discovery just in time for the next flight of the TKS, Kosmos-1267.

The picture below shows the orbital history of Kosmos-929. The day when the VA detached (30 days after launch) is marked.


The flight of Kosmos-1267

When Kosmos-1267 was launched, the Kettering Group immediately identified it as another "Kosmos-929"-type mission.

Thus, on 25 April 1981, Jan-Ola Dahlberg in Malmö picked up telemetry at 0940 UT on 19.954 MHz, 12 hours before TASS announced the flight. Since the launch took place at 0201 UT (3), Jan-Ola had picked up the signals on the fifth orbit. Remarkable! Dick Flagg in Florida also received shortwave telemetry  on launch day. We also discovered a second frequency, 19.942 MHz being used by this spacecraft.  Short-wave telemetry from Kosmos-1267 was similar, but certainly not identical to that from Kosmos-929 (see story on TKS shortwave telemetry).

On the first day we also realized that the orbital plane of  Kosmos-1267 was about ten degrees from that of Salyut-6 and that they would come together in roughly a month's time. They would have done so if the orbit of Kosmos-1267 had not been raised.

The following day I was able to pick up telemetry on 247 MHz, confirming the discovery of signals on this frequency from Kosmos-929 (see story "Tracking satellites with a solar radiospectrograph" at this web site). These signals were also picked up occasionally by Dick Flagg in Florida, indicating the presence of a tracking ship in the vicinity.

Within ten of launch Kosmos-1267 had maneuvered up to an orbit with a period corresponding to a 63-rev repeating pattern. As far as I can ascertain the VA was detached from the FGB on day 144 (May 24, 1981), the 29 th day of flight (the Kosmos-929 VA detached after 30 days), and was recovered around 1440 UT that day. The FGB, remaining in orbit, maneuvered to an orbit with a 78-rev repeating pattern almost exactly 32.5 days after launch - just like Kosmos-929!

When the orbit of Kosmos-1267 was raised the rate of approach between the orbital planes of this craft and Salyut-6 decreased somewhat and a straight-line extrapolation showed that the orbits would be co-planar on day 169 or 170, i.e. 18 or 19 June 1981(see figure on the right). We just had to wait and see.

Early in the morning of 19 June 1981 I watched as telemetry signals from Salyut-6 (192.0 MHz) and Kosmos-1267 (247.0 MHz)  seemed to disappear below my radio horizon within 20 seconds from each other. Obviously the craft were extremely close when I lost Kosmos-1267 at 0650.42 UT. The shortwave transmitter on 19.954 MHz on Kosmos-1267 was swicthed off abruptly at 0646.56 UT, something that I had not heard happening at any time earlier during the flight.

On the next rev I could not detect any difference in reception times. Actually the docking had taken place at 0652 UT, just after I lost the signals on the first pass that morning. TASS announced the docking at 0930 UT!.

After the docking had occurred, TASS lifted part of the veil around Kosmos-1267 and issued an intriguing, but somewhat vague statement about its mission and characteristics:

"The Soviet Union has started a new space experiment. An earth satellite of the Kosmos series has been docked with the Salyut-6 orbital station now operating in the automatic mode. The Kosmos satellite has a mass more than double that of a Soyuz spacecraft in which cosmonauts have been making their flights. The experiment is being conducted under the program to establish big space complexes. The satellite has delivered propellant needed for maneuvers by the station. The Salyut-6 orbital station has now been in orbit for nearly four years. Over thirty manned and unmanned spacecraft have docked with it."

This was indeed interesting at the time. It implied that the craft that had docked with Salyut-6 weighed in excess of 13000 kg, agreeing rather well with the figure 13266 kg for the FGB mass (1).

Interestingly, at the end of June 1981, according to UPI, Konstantin Feoktistov, cosmonaut and spacecraft designer, had remarked that

"Kosmos-1267 was a prototype for future Soviet space modules" (5).
At this time the choice away from the Kvant-type modules, the 37K-series, where and FGB would work as a tug to bring a separate module to a station to the 77K concept eventually selected for Mir in which the FGB tug and the payload were integrated in one system had not yet occurred (4). So, what did Feoktistov refer to? The upcoming Kosmos-1686 mission or the FGB tug for Kvant and other modules on the drawing boards? Hard to say. During June 1981, amomentous event had occurred; the branch of Chelomei's design bureau (Fili branch) that ahd designed the main part of the TKS, the FBG, had just been wrested from Chelomey and put into the hands of what is now known as NPO Energiya, Feoktistov's employer!

Last signals on 247 MHz were received by me on 3 October 1981, around the time when Kosmos-1267 performed the last engine firing to test the structural integrity of the orbital complex. The last signals on 19.954 MHz were received by me on 20 May 1982, two months before the decay of the Kosmos-1267/Salyut-6 complex on 29 July 1982. However, I must admit that I did pay scant attention to Kosmos-1267 during the spring and summer of 1982, since Salyut-7 had just been launched and took most of the attention of amateur space trackers.

The flight of Kosmos-1443

In mid 1982 the decision was taken never to put crews in TKS's and the remaining craft would be used in conjunction with Salyut-7, a product of NPO Energiya (3). in early 1982 the third TKS was prepared for launch. The launch escape tower had been removed and the crew seats had been removed to make room for cargo. The last TKS with a VA return capsule, Kosmos-1443, was launched at 0937:08 UT on 2 March 1983.

TASS announced the flight at mid-day UT and the announcement said that the craft would perform a joint flight with Salyut-7. Geoff Perry in Kettering picked up short-wave telemetry on 19.954 MHz at 1532:20 UT. This craft also had only a single telemetry mode on shortwaves. It showed some similarities to that Mode B of Kosmos-1267. The initial orbit was 1.25 degrees from the orbital plane of Salyut-7 and the orbital planes would have merged on 6 March if no maneuver was made.

On 6 March radio observations showed that the orbital period had been raised the day before  to a value near 90.4 minutes.  It was then obvious that the orbital planes would merge on 10 March. And, indeed, around 1000 UT on 10 March , TASS announced that the docking occurred at 0920 UT.  At docking short-wave telemetry ceased, but was was resumed on 11 March. On 3 July 1983, Pravda published a sketch of Kosmos-1443 (see picture above right). This was a great event at the time. Seven years after the appearance (Kosmos-929) of what we now know was the TKS, we finally knew what it looked like.

What we did not realize was that this was not the start of something new - that vehicles just like this would serve future space stations - but rather the end of a story. In the Soviet logic, they could reveal the appearance of a space system when there was something more modern in development. This was the case when Vostok was revealed (Soyuz was in development). We should have realized this in 1983 and understood that Kosmos-1443 was the end of a line - the complete TKS.

On 13 August I had a phone call from Dick Flagg who said he had heard that Kosmos-1443 would undock from Salyut-7 and land "next week". In the morning broadcast in English from radio Moscow on 15 August 1983 it was announced that

"The Soviet cargo spaceship, Kosmos.1443, has separated from the station, Salyut, and is returning to Earth. ....test were made of onboard systems, units, and structural elements of future spacecraft and exercises were held inmanaging large space comlexes."

The undocking occured at 1404 UT on 14 August. The VA crew return vehicle finally landed with 317 kg of cargo at 1302 UT on 23 August 1983  (3).. As described elsewhere (3) this capsule was sold to the Perot Foundation at the Sotheby's auction on 11 December 1993 in New York City (see picture on the right). It is displayed at the National Air & Space Museum in Washington D.C.

The flight of Kosmos-1686

TKS-M, a.k.a. Kosmos-1686, was launched at 0841:42 UT on 27 September 1985. This craft did not have a functional VA, but instead an extensive set of instruments for military tests in space. Indeed, at this time the decision to develop add-on modules to Mir based on the FGB service part of the TKS had been taken (4). Kosmos-1686 can therefore be regarded as a prototype for later add-on modules to Mir. However it still carried subsystems very similar to those of the original TKS vehicle. Thus, telemetry was again received on 19.954 MHz and 247.475 MHz (see article on TKS HF telemetry). Kosmos-1686 docked with Salyut-7 on 2 October 1985. The resident crew on the space station had been launched to Salyut-7 just ten days before Kosmos-1686. The resident crew consisted of Vasyutin, Savinykh and Volkov - a "military" crew.

The Kettering Group  received normal telemetry and voice from the crew during October and most of November 1985. However, at 1909.05-1913.40 UT on 13 November 1985 I picked up scrambled voice (listen to 13 Nov 1985 recording here) (of the same type as that received from Salyut-6) indicating that something confidential was discussed, probably a medical problem. The Kettering Group received more scrambled voice in the days to follow (16 and 17 November). Interestingly, the 20.008 MHz telemetry transmitter also began to be heard at this time, indicating that the status of the return ship was of great interest. It was therfore not entirely surprising when the crew landed at 1031 UT on 21 November because Vasyutin was ill. Reportedly he had a high fever (40 C, 104 F) and suffered from an inflammation of some sort (6).

This was evidently a setback for the intended mission of Kosmos-1686 and another visit to Salyut-7 to finish the work with the TKS-M was carried out in 1986 by the Soyuz T-15 crew in connection with its fascinating and unique expedition from Mir to Salyut-7 and back again to Mir. Cosmonauts Kizim and Solovyev stayed on Salyut-7 from 6 may until 25 June. This was the last time Salyut-7 was manned. It seems that there were plans to visit again, but these had to be abandoned when the orientation system of Kosmos-1686 failed in December 1989. Salyut-7 with Kosmos-1686 decayed from orbit on 7 February 1991. I received the last transmission from Kosmos-1686 on 19.954 MHz on 27 November 1989.

Strange events

In (3) there is a fascinating account about Chelomei's son sitting in the TKS during tests and interrupting the test to avoid U.S. ELINT satellites. Presumably the telemetry transmitters were on. This led me to recall a few strange occasions when the Kettering Group picked up typical FSK-PDM shortwave telemetry that were ground-based (no Doppler shift) while a spacecraft with similar telemetry format and frequency was in orbit. Here are the two instances:

14 and 19 July 1976
There were signals on 19.944 MHz with the same telemetry format type but with different word values compared to Salyut-5 but transmitted overlapping with Salyut-5 on the same frequency. For example: on 19 July Salyut-5 transmitted 1122-1144 UT while the ground based signal was on between 1138-1211 UT! Very strange!

1, 2, and 4 August 1987
A signal was present on 19.955 MHz with the same telemetry format type but with different word values compared to Kosmos-1686. the transmissions from the ground did not overlap with those from Kosmos-1686 in time or in frequency, because Kosmos-1686 was on 19.954 MHz (which is indeed very close in frequency).

What were these ground-based signals? Simulators of OPS and TKS up and running while the ships were in orbit?


  1. Asif A. Siddiqi: The Almaz Space Station Complex: A History, 1964-1992, part 1, JBIS, Vol 54, No 11/12, November/December 2001.
  2. Russian Space History, catalogue of the auction at Sotheby's sale 6516 in New York, 11 December 1993, item. 154.
  3. Asif A. Siddiqi: The Almaz Space Station Complex: A History, 1964-1992, part 2, JBIS, Vol 55, pp. 35-67, 2002.
  4. Bart Hendrickx, The Origins and Evolution of Mir and its Modules" JBIS, Vol. 51, No. 6, June 1998, pp. 203-222.
  5. Geoff Perry, day-to-day log, entry for 29 June 1981.
  6. Nicholas L. Johnson: "The Soviet Year in Space 1985", Teledyne Brown Engineering, 1986, p. 57

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