Zond-5: A prototype of the Soviet crew capsule loops behind the Moon!
In September 1968, alarms probably sounded at US intelligence agencies and NASA, as the USSR finally succeeded in flying a crew vehicle prototype around the Moon during the Zond-5 mission. The first ever return of a spacecraft from the lunar vicinity, though only with tortoises and small organisms onboard, underscored for the US leadership the enormous importance of a recent decision to send the Apollo-8 crew into the lunar orbit before the end of the year. The Moon Race was quickly approaching its climax.
The Zond-5 spacecraft is being prepared for flight.
The Zond-5 mission at a glance:
Mission of Vehicle No. 9L
Just two weeks after the successful flight of the Soyuz 7K-OK No. 9, leaders of the Soviet lunar program switched their full attention to the 8th attempt to test the 7K-L1 spacecraft designed for a mission behind the Moon. According to the original plans made in April 1967, Vehicle L1 No. 9 could carry the second crew around the Moon, but after a string of failures and delays with previous missions, it became the third attempt to rehearse in automated mode the exact flight profile of the circumlunar mission with two cosmonauts onboard. (774)
Vehicle No. 9L possibly was the first to be equipped with the AFA-BA/40 imager built at the Kazan Optical and Mechanical Plant, KOMZ. The serially produced aviation camera was modified for the purposes of the L1 mission at the experimental and production shop of the Aerial Photography Department at the MIIGAiK geodesy and cartography institute.
The spacecraft also carried live animals — a pair of tortoises and other biological organisms first of all for radiation studies. (52)
Head of cosmonaut training Nikolai Kamanin and cosmonauts of the L1 project, including Valery Bykovsky, Pavel Popovich, Oleg Makarov, Valery Voloshin and Nikolai Rukavishnikov, arrived at Tyuratam on Sept. 10, 1968. They were accompanied by many members of the State Commission overseeing the launch of Vehicle No. 9L.
After consultations with Georgy Tyulin, who traditionally chaired the State Commission, the final pre-launch meeting of its members was set for September 13. In addition to the immediate business of the upcoming launch, Kamanin and Tyulin already began discussing plans to roll out a prototype UR-500K rocket to the pad, to give the cosmonauts an opportunity to practice final boarding operations with the L1 vehicle.
To support the launch of Vehicle No. 9L and the landing of its descent module a week later, a total of 200 planes and helicopters were mobilized along the ascent trajectory and the primary landing site in Kazakhstan. Simultaneously, eight Soviet ships were deployed 300 kilometers from each other in the Indian Ocean. They were responsible for the 2,500 by 400-kilometer area which would be used for a ballistic descent and splashdown, in case if the spacecraft failed to enter in aerodynamic descent mode allowing it to reach Soviet territory. However only three of the ships had onboard K-25 search and rescue helicopters, according to Kamanin.
Fortunately, the weather both in the USSR and in the Indian Ocean was good for launch.
On the morning of September 12, Head of TsKBEM design bureau Vasily Mishin and his closest associates also arrived in Tyuratam to oversee the final preparation.
The crucial meeting of the State Commission opened at 18:00 Moscow Time on September 13 at the new three-story building at Site 81, just a few hundred meters from the pad. Yuri Trufanov, deputy head of TsKBM, which developed UR-500K vehicle, confirmed that the rocket was in good shape and Mishin's deputy Yevgeny Shabarov assured that the L1 ship was also ready to go. Several dozens of other officials reported on the status of various systems. In the end, the liftoff was approved for September 15, at 00:42:10.6 Moscow Time.
Kamanin raised an issue during the meeting over the landing time of the upcoming mission. Vehicle No. 9L was scheduled to come down around 19:00 Moscow Time on September 21, in essentially night-time conditions both in Kazakhstan and in the Indian Ocean. Kamanin was especially concerned about a water landing, because without a light beacon, the search for the capsule in the ocean could be very difficult and during a 12-hour dark period, it had plenty of time to sink. Kamanin asked Mishin's deputy Melnikov whether the landing could be shifted to the daylight period. Melnikov replied that it would be difficult (given the inflexible nature of the L1 flight scenario and the restrictions of the launch window for lunar missions). However, he promised to study the issue, while Mishin was much more categorical and claimed that absolutely nothing could be done. Still, the commission recommended that Melnikov review the problem and report his findings at the next meeting, probably regarding future launches.
On September 14, the launch personnel had a traditional backup day to resolve last glitches, while Kamanin and the cosmonauts spent much of the day hunting and fishing in the steppe along the Syr Darya river. There were clear skies over Tyuratam with warm temperatures around 20C degrees. The forecast predicted a similar weather for the launch day. (820)
Zond-5 lifts off
The L1 No. 9 spacecraft lifted off from the "Left" launch pad at Site 81 in Tyuratam as scheduled on Sept. 15, 1968, at 00:42:10.77 Moscow Time. It was the 11th mission for the UR-500 rocket series and the seventh launch of the UR-500K variant equipped with the Block D (11S824) stage. (400)
Kamanin and a group of officers watched the launch from a tracking station at Site 97. The night sky was cloudless and the half of the moon disk was right above their heads. At T+126 seconds in flight, Kamanin saw the separation of the first stage at an altitude of 42 kilometers. The emergency escape rocket and the payload fairing were also jettisoned as scheduled at T+185 seconds. Even the ignition of the third stage, taking place at T+338 seconds at an altitude of 130 kilometers, was discernable, according to Kamanin.
The third stage climbed to a maximum altitude of 161 kilometers and separated at T+589 seconds. The Block D/L1 stack then continued in free ballistic flight for 251 seconds before the upper stage fired its engine for the first time at T+840 seconds. After an agonizing wait, it was confirmed that the Block D had ignited its main engine as scheduled and then successfully completed the 108-second burn to reach an initial parking orbit.
Kamanin recorded the following parameters for the parking orbit:
Next, there was a 56-minute passive flight, before the second firing of Block D to enter a trans-lunar trajectory. During that period, Kamanin caught a ride from Site 97 to the central processing area at Site 2, where there was a well-equipped command post with a direct line to a nearby tracking station. At Site 2, Kamanin saw all the top brass, many of whom already celebrated a success, because they were not involved in the upcoming week-long effort to navigate the L1 spacecraft around the Moon. (820)
Soon after the launch, western radar caught a total of three objects in orbit. Two objects quickly reentered on September 16:
The third object with the COSPAR designation 1968-076C (NORAD ID: 3396) was tracked losing altitude a bit slower until its reentry on September 18:
In the meantime, around 67 minutes after the liftoff, the Block D stage successfully inserted Vehicle No. 9 on its trans-lunar trajectory and the Soviet Union then announced the mission as Zond-5. The official statement gave no details about its destination. However, the lunar Greenwich Hour Angle indicated to independent observers that the spacecraft was heading in the direction of the Moon. (50)
Early afternoon on September 16, cosmonauts from the L1 group boarded an Antonov-24 aircraft for a trip to the NIP-16 tracking station in Crimea, which was the nerve center of all deep-space missions. Tyulin, Mishin and Kamanin stayed behind in Tyuratam, because they had to participate in the important meeting of the State Commission on the N1-L3 project scheduled for September 18.
Mission control struggles to bring Zond-5 home
On September 16, Kamanin got a call from Crimea informing him that, the L1 spacecraft had trouble with maintaining its attitude in space, putting the upcoming trajectory correction at risk and, possibly making the circumnavigation of the Moon impossible. Ground controllers had spent the previous night analyzing the situation. (820)
As it turned out, the 100K star tracker, which was needed to determine the orientation of the spacecraft in space, failed to work due to contamination of its optical surfaces. Ironically, the contamination was apparently caused by vapors from a newly introduced blind, which was heated by sunlight that it was supposed to prevent from entering the sensitive tracker. (52)
Engineers continued struggling with broken star trackers for most of the day on September 16, delaying the trajectory correction. Upon his arrival at Tyuratam on September 17, Minister of General Machine-building Sergey Afanasiev directed Mishin and Tyulin to fly to Crimea to help troubleshoot the situation. (820)
On the morning of September 17, Pavel Popovich called Kamanin and told him that the orbit correction had been finally completed, thanks to the orientation using the position of the Earth and the Sun. (820, 774) At the time, the spacecraft had reached a distance of 325,000 kilometers from Earth and was already approaching the Moon. (2) The maneuver was performed with the main KDU propulsion system around 03:11 GMT on September 17, on the command sequence uplinked to the spacecraft by mission control. (50)
The accuracy of the Earth-Sun orientation method was lower than that of the nominal attitude control, using the celestial navigation system, but it was still good enough for the flight around the Moon and the return to Earth. (820)
Ground controllers still held hope for troubleshooting star trackers for the second half of the journey, but it looked increasingly likely that the Zond-5 would come down in the Indian Ocean, about which Kamanin informed search and rescue officials.
On September 18, Zond 5 reached the farthest point of its trajectory and after a swing over the Far Side of the Moon at a minimum distance of 1,960 kilometers, began its a trek back to Earth. (2)
By September 19, it was absolutely clear that the celestial navigation system was completely dead and that the mission would be concluded with a ballistic descent into the Indian Ocean. (820)
The situation was further complicated by the fact that the motor responsible for the movement of the three-axis stabilization gyroscope along the pitch axis stalled aboard the spacecraft. The failure was caused by a control error, which failed to turn off the autonomous flight control system in time. (52)
Moreover, the high-gain antenna aboard the spacecraft, which was used to communicate with the spacecraft, was not pointing at Earth as required. The investigation revealed that settings for the operational logic of the antenna's own 101K Earth-seeking sensor, inserted during pre-launch processing, were not matching the mechanical calibration of the antenna due to an error in the operational documentation. (52)
However, the firing the KDU engine for a braking maneuver in order to put the spacecraft on the proper trajectory for a controlled reentry on September 21 proved impossible.
Instead, a joint team of mission controllers and developers deployed at Yevpatoria, Crimea, came up with an alternative totally improvised method to brake the spacecraft. They used the single remaining 99K optical solar sensor to establish the attitude of the vehicle relative to the Sun. Next, they pointed the left side of the spacecraft against the direction of the flight and commanded a small sideway-facing URMD attitude control thruster to fire for a short period of time. They then turned the spacecraft 180 degrees and fired a thruster on the opposite site of the spacecraft against the direction of the flight.
Mission control continued alternating left and right side firings for the next 20 hours, trying to accumulate enough reduction in velocity for a survivable entry corridor over the Indian Ocean. (52)
After a total of 36 communications sessions with mission control, that effort was successful, placing the Descent Module on a trajectory with a nominal perigee of just between 35 and 45 kilometers above the Earth's surface. (2) That corridor guaranteed that the capsule would neither bounce back into space, nor burn up in the atmosphere once the ballistic reentry began over the Indian Ocean on September 21 at 15:54 GMT. (50)
The Descent Module of the Zond-5 spacecraft in the water of the Indian Ocean after its splashdown on Sept. 21, 1968, with its open parachute hatch and the released antenna. The photo released by the Soviet press revealed to observers that the Soviet spacecraft closely resembled the Soyuz spacecraft.
At an altitude of around seven kilometers, while still moving at a speed of 200 meters per second, the descent module began releasing its parachute system, followed by a successful splashdown at 19:08 Moscow Time (16:08 GMT). (2) It became the first human-built vehicle to complete a circumlunar journey and return to Earth with the second cosmic speed.
Both American and Soviet ships were apparently heading to the splashdown site located at 32 degrees 38 minutes South latitude and 65 degrees 33 minutes East longitude.
Because only Soviet ships had the necessary search and recovery equipment, they were able to pick up the capsule first. (52) The module with a final mass of 2,046 kilograms was successfully brought to the deck of the Soviet recovery ship. (2)
On September 23, the official Soviet TASS news agency issued a communique, announcing the successful return of the Zond-5 mission. (52) Behind the scene, the final technical meeting on the results of the Zond-5 mission took place on the morning of Sept. 25, 1968. (774)
Only on October 3, did the Descent Module from the Zond-5 mission arrive aboard the Vasily Golovin vessel to the port of Bombay, from where it was airlifted to Moscow inside a special container. (231, 50)
Once the Descent Module arrived at its assembly plant in Podlipki, specialists extracted the tortoises from the capsule, which turned out to be in good shape, even though they would not survive the subsequent medical studies, which would confirm that live organisms can make a safe lunar journey, including crossing the radiation belts around the Earth. (231)
AUTOMATED STATION "ZOND-5" FLOWN AROUND THE MOON SUCCESSFULLY RETURNED BACK TO EARTH WITH THE SECOND COSMIC SPEED:
As was already reported, on Sept. 15, 1968, the Zond-5 automated space station was launched in the Soviet Union. After a seven-day flight on the path Earth-Moon-Earth, the station returned to Earth.
For the first time in the world, the Soviet spacecraft, after flying around the Moon, successfully returned to Earth with the second cosmic speed, delivering a large amount of scientific information.
At 18 hours 54 minutes Moscow Time on Sept. 21, 1968, the automated station entered the atmosphere of the Earth with the second cosmic speed of around 11 thousand meters per second and at 19 hours 08 minutes splashed down at a pre-calculated region of the Indian ocean.
The splashdown was performed at a point with coordinates 32 degrees 38 minutes South latitude and 65 degrees 33 minutes East latitude. The motion of the station in the atmosphere during the phase of aerodynamic braking was along a ballistic trajectory.
The descent of the station after the aerodynamic braking was performed with the use of the parachute system. The automated station along with scientific instruments was lifted aboard a Soviet ship of the search and rescue service.
During the flight of the Zond-5 automated station the following were accomplished:
In the process of the flight, there was testing of the systems and machinery for maneuvering on the trajectory and reentry. The flight control system of the station and radio-technical means of measuring the parameters of its trajectory provided the solution of tasks at hand.
The program of scientific research of cosmic space and integrated tests of onboard systems and machinery of the Zond-5 automated station has been fully completed.
The successful flight of the Zond-5 automated station on the route Earth-Moon-Earth, and its return into the assigned region constitutes an outstanding achievement of the Soviet science and technology. There was resolved a new scientific and technical problem and it opened wide prospects for the further exploration of cosmic space and planets of the Solar System with automated space stations with the return of results of the research back to Earth.
Pravda, Sept. 23, 1968. (52)
Read much more about the history of the Russian space program in a richly illustrated, large-format glossy edition:
The 7K-L1 No. 9 spacecraft is being integrated with its payload fairing during pre-launch processing. Credit: RKK Energia
A still from the Soviet era animation showing the trajectory of the Zond spacecraft. Click to enlarge. Credit: Roskosmos
Leading designer of the UR-500K (Proton) rocket Yuri Trufanov led its preparations for test launches with the 7K-L1 spacecraft. Credit: GKNPTs Khrunichev
Evgeny Shabarov, deputy to Vasily Mishin, led preparations for the launch of L1 No. 9 (Zond-5) vehicle.
A photo of the Earth attributed to the Zond-5 mission and taken from a distance of 85,000 kilometers. Credit: RKK Energia
A container with the Descent Module of the Zond-5 spacecraft departs a port of Bombay for a trip to the airport, where it would be picked up by a transport plane for a trip to Moscow.
An official TASS announcement about the successful completion of the Zond-5 mission. Click to enlarge.
A reproduction of a painting by Andrei Sokolov published in the Pravda newspaper on Sept. 23, 1968, was clearly designed to hide the true identity and architecture of the 7K-L1 spacecraft.
A footage of tortoises possibly filmed after their flight around the Moon aboard Zond-5.