The continuing enigma of Kosmos 146 and Kosmos 154

By Sven Grahn and Bart Hendrickx

Basic data about the Kosmos 146/154 flights

Two test flights of the UR-500K/L1 system were performed in March and April 1967 under the designations Kosmos 146 and Kosmos 154. In the table below the flights are summarized:
Spacecraft Launch date Launch time
Period Signals on
Kosmos 146 (7K-L1 no.2P) 10 March 1967 11:30:32.8 51.44 177 296 89.20 20.008
Kosmos 154 (7K-L1 no.3P ) 8 April, 1967 09:00:32.7  51.3 183 223 88.50 19.995

These flights have been regarded as tests of the Zond complex involving the firing of the fourth stage of the UR-500 rocket to put the L1 spacecraft into an elliptical trajectory to test high speed re-entry. Considerable disagreements exist as to what happened to these flights. Did they fail, and if so, why? The picture blow shows what these space vehicles would have looked like in earth orbit.

Were they aimed at the Moon?

The first question that arises is whether or not these spacecraft, if intended to leave Earth orbit, were aimed at the Moon. The line in the graph below shows the launch time for a Zond to the Moon as a function of Lunar Age at the time of launch. This graph is based on a method to calculate the launch time (expressed in fractions of a day, UT) which is very simplistic and does not take into account the detailed astrodynamics near the Moon. It is based on the simple assumption that the Moon (at the time of arrival) must be close to the orbital plane of the low parking orbit (before trans-lunar injection). As we can see from this graph Kosmos 146 and 154 were not aimed at the Moon.

Orbital data for Kosmos 146

Orbital elements show that a major event occurred with Kosmos 146 between orbit 10 and 22. Two objects were tracked that disappeared from low earth orbit within one day, one of these was catalog number 2815. Two other objects (2705 and 2709) continued in orbit for about 8 days. Signals were intercepted from one of these objects on 20.008 MHz by several stations in Europe (See SPACEFLIGHT, Vol 23, No 3, March 1980, pp 121-123). So, obviously something was intended to happen after about one day in orbit. Was this the time intended for injection into a highly elliptical orbit? If so, this is quite surprising, because all subsequent use of the fourth stage (Block-D) has been such that the second firing has taken place on the fist orbit while passing northbound over the South Atlantic.

Why stay in low earth orbit for about a day?

It is indeed much more demanding to keep the upper stage working for more than 24 hours than for just 2 hours. So, why would this early launch have utilized this unusual launch scenario? A possible explanation is given in an article by Bart Hendrickx in the April 1995 (Vol. 37) issue of SPACEFLIGHT. Here is what he writes:

"...Surprisingly, the original L-1 flight plan, discussed during a 24 December 1966 meeting of the L-1 state commission, envisaged a dual launch scenario, It was decided to launch the L-1 unmanned on Proton and subsequently send up a two-man crew on a Soyuz spacecraft, the reason being that the three-stage Proton rocket (UR-500K) earmarked to launch L-1 and its Block-D escape stage hand not flown at the time. Following docking with the L-1/Block-D combination in Earth orbit the crew would space walk to the L-1, following which the Block-D would boost the L-1 to the Moon and the Soyuz would return to the earth unmanned. It was not until early June 1967, by which time the UR-500K had made two successful launches, that this plan was abandoned in favour of a single launch scenario on Proton...."

Why was short-wave telemetry used?

Well, to make this scenario work the Block-D must have been able to stay in working condition in orbit for more than a day. Therefore, it seems reasonable that the Kosmos 146 and 154 test flight would have tested the endurance of the Block-D in low earth orbit. This can also explain the presence of a shortwave transmitter on the vehicle. If the vehicle operated only for one orbit, there could be tracking ships stationed at various spots along this single orbit and no over-the-horizon radio monitoring would be needed. During a flight of one or two days, the use of a short-wave transmitter can make sense. If ionospheric conditions are not too unfavourable, the status of the vehicle could be monitored quite easily almost around the earth with a few stations on Soviet soil.

What Russian sources say

But, what actually happened? Was Kosmos 146 boosted out of earth orbit? Western sources usually say "De-orbit or escape?" What happened to Kosmos 154? The following summary of information about these two flights from various Russian sources has been compiled by Bart Hendrickx:

Kosmos 146

In Phillip Clark's book "The Soviet Manned Space Programme" Valentin Glushko is quoted as saying that C. 146 reached "second cosmic velocity". Glushko also gives the mass of Cosmos 146 as 5017 kg.

Astronomia, Kosmonavtika (Znaniye), December 1991 : "[The Kosmos-146 launch], which used the first four-stage UR-500K with a Block-D upper stage, was meant to test the upper stage. The L-1 vehicle was launched in a simplified version. During the flight two firings were conducted of the Block-D's liquid rocket engine."

Kamanin diaries 11 March 1967 : "Yesterday the Soviet Union launched the first L-1 vehicle (in the press it has been called Kosmos-146). All engines of the UR-500K functioned beautifully and the ship was boosted to second cosmic velocity and sent to the Moon. This is where the experiment ended, but the important thing is that this was the fourth successful launch of the UR-500K out of five attempts. One similar launch of an L-1 vehicle is envisaged by the programme to prepare for a lunar fly-around".

(This entry could represent a problem : it would indicate that the Block-D was fired fairly early in the mission and that Kosmos-146 did not coast in low orbit for more than a day. But, on the other hand, if the Block-D second firing occured at midday on the 11 th, this event would have been included in Kamanin's diary for that day, if Kamanin wrote the diary late at night every day).

Novosti Kosmonavtiki 18-31 Dec 1993 : an article about engines of the Kosberg bureau by Timothy Varfolomeyev : ".... The first flight test of the DU 8D49 as a third stage engine for the 8K82K booster took place on 10 March 1967. The rocket placed into a highly elliptical orbit a prototype of a manned circumlunar vehicle (7K-L1P), named Kosmos-146 by TASS".

Novosti Kosmonavtiki supplement (June 1995) (list of man-related launches) : Kosmos-146 (7K-L1P) : first unmanned test flight of a circumlunar vehicle. Tests of the Block-D, ensuring the ship's boosting to the Moon.

Kosmos 154

Kosmonavtika, Astronomiya (Znaniye), Dec 1991 "In April 1967, under the cover name Kosmos-154, the third model of the L-1 was placed into near-Earth orbit. Because of a control system failure that resulted in the premature jettisoning of the ullage motors, the main propulsion system of the Block-D did not ignite".

Kamanin diaries 6-9 April 1967 : First Kamanin describes how he and a group of chief designers and ten cosmonauts headed by Leonov and Popovich arrived at the cosmodrome on 6 April. The following day they visited Complex 92 to take a close look at the Proton rocket. The launch took place "under clear blue skies" on 8 April at 12.00.08 Moscow time. He then goes on : "All three stages of the rocket and the Block-D upper stage worked fine and lunar ship nr. 2 (Kosmos-154) was successfully placed into Earth orbit. Forty minutes later the members of the State Commission and the chief designers met in Area 2 in Kirillov's office. Everyone congratulated Chelomei with the success. But placing the ship into orbit was only the first step. In a day's time the Block-D has to be fired again to send the ship to the Moon. Although operations like this have been successfully carried out more than ten times [he must be referring to the Molniya's Block-L], it is too early for Mishin, who's responsible for the Block-D, to declare victory".

On 9 April he goes on : "Yesterday we were all happy with the successful launch of the UR-500K with the L-1 vehicle, but today, due to Mishin's fault, we experienced the bitter taste of defeat : the Block-D did not ignite and we cannot send the ship to the Moon. The L-1 capsule has an automatic device which after the first firing of the Block-D casts off the [ullage motors]. During the launch of lunar ship nr. 2 this automatic device should have been switched off, because it had been decided to fire the Block-D twice : first to put the complex into Earth orbit and then to boost it to second cosmic velocity. The orders to switch off the device had been given by Tyulin, but due to the negligence of Mishin they were not carried out. The ship went into orbit with the automatic device switched on and the latter did its work "faultlessly" after the first burn of the Block-D".

Novosti Kosmonavtiki supplement (June 1995) (list of man-related launches) : Kosmos-154 (7K-L1P) : unmanned test flight of circumlunar vehicle. Tests of the Block-D did not take place because of a mistake during preparations


It seems that Kosmos 146 and 154 were launched to test the Block-D trans-earth injection burn and that this may have worked fine for Kosmos 146, but not for Kosmos 154. Judging from Kamanin's comments, there were no further plans for re-entry tests with the L-1. It also seems that the Block-D escape burn was scheduled to occur one day into the mission to demonstrate support for the scenario in which the crew of the L-1 would have been launch in a Soyuz to dock with the L-1/Block-D combination! Did anyone in the West pick up evidence of the L-1 in the elliptical orbit, and how elliptical was it??

[Sven's Space Place]

[Space History Notes]