Results: Identical to Venera 5, Venera 6 reached Venus after performing 63 communications sessions with Earth and one mid-course correction at a range of 15.7 million kilometers from Earth on 16 March 1969. Its 405-kilogram lander separated from the main bus 25,000 kilometers from the planet and entered the Venusian atmosphere at a velocity of 11.17 kilometers/second at 06:05 UT on 17 May 1969. The Venera 6 capsule transmitted data for 51 minutes before contact was lost, probably at an altitude of about 18 kilometers. Pressure was 27 atmospheres at loss of contact, similar to that measured by Venera 5 at a much higher altitude indicating that Venera 6 may have come down over a mountain or high plateau. Landing coordinates were 5° S / 23° E. Results from the Venera 5 and 6 missions, published by the Soviets in March 1970, seemed to confirm and sharpen earlier findings from Venera 4, suggesting that the planetary atmosphere consisted of 97% carbon dioxide, <2% nitrogen, and <0.1% oxygen. Data from Venera 6 suggested the ground pressure was about 60 atmospheres and ground temperature was about 400°C. This data compared with Venera 4's readings which indicated pressure at 75 atmospheres and temperature at 500°C.
103
[Zond, 7K-L1 no. 13L]
Nation: USSR (59)
Objective(s): circumlunar flight
Spacecraft: 7K-L1 (no. 13L)
Spacecraft Mass: c. 5,375 kg
Mission Design and Management: TsKBEM
Launch Vehicle: Proton-K + Blok D (8K82K no. 237-01 + 11S824 no. 20L)
Launch Date and Time: 20 January 1969 / 04:14:36 UT
Launch Site: NIIP-5 / Site 81/23
Scientific Instruments: [unknown]
Results: This was the sixth attempt at a robotic circumlunar flight in support of the L1 piloted lunar program and the first after the resounding success of the American Apollo 7 in December 1968. The Proton launch vehicle lifted off on time and first stage operation was nominal. However, during second stage firing, one of the four engines of the stage spuriously switched off at T+313.66 seconds, about 25 seconds early. The other engines continued firing (and could have actually compensated for the loss of thrust), but subsequently, the primary third stage engine also switched off early during its firing sequence, at T+500.03 seconds, due to a breakdown in the main pipeline feeding fuel to the fuel gas generator. After a near-ballistic flight, the L1 payload landed (and was recovered) southeast of Irkutsk near the border between the USSR and Mongolia.
104
[Luna, Ye-8 no. 201]
Nation: USSR (60)
Objective(s): lunar roving operations
Spacecraft: Ye-8 (no. 201)
Spacecraft Mass: c. 5,700 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Proton-K + Blok D (8K82K no. 239-01 + 11S824 no. 201L)
Launch Date and Time: 19 February 1969 / 06:48:48 UT
Launch Site: NIIP-5 / Site 81/24
Scientific Instruments:
-
- imaging system (two low-resolution TV + four high-resolution photometers)
-
- x-ray spectrometer
-
- penetrometer
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- laser reflector
-
- radiation detectors
-
- x-ray telescope
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- odometer/speedometer
Results: The Ye-8 represented the "third generation" of Soviet robotic lunar probes. The basic Ye-8 comprised a lander stage (the "KT") topped off by an eight-wheeled remote-controlled lunar rover (the "8YeL") for exploring the Moon's surface. Essentially a pressurized magnesium alloy container on wheels, the 8YeL was designed to operate over a period of three lunar days (i.e., roughly three Earth months) and collect scientific data from various points on the lunar surface. This first attempt to put the rover on the Moon was a complete failure. At T+51.42 seconds, the payload stack disintegrated and the booster exploded at T+54 seconds. Debris landed about 15 kilometers from the launch site. Later investigation indicated that maximum dynamic pressure during the ascent trajectory tore the new and untested payload shroud off at its weakest tension points. Despite an intensive effort, searchers were unable to find the polonium-210 radioactive isotope heat source in the rover. Unconfirmed rumors still abound that soldiers at the launch site used the isotope to heat their barracks during the bitter winter of 1968–1969.
105
[N1 launch test, 7K-L1S no. 2]
Nation: USSR (61)
Objective(s): lunar orbit
Spacecraft: 7K-L1S (no. 2)
Spacecraft Mass: 6,900 kg
Mission Design and Management: TsKBEM
Launch Vehicle: N1 (no. 15003)
Launch Date and Time: 21 February 1969 / 09:18:07 UT
Launch Site: NIIP-5 / Site 110/38
Scientific Instruments: [unknown]
Results: This was the first attempted launch of the giant N1 booster as part of early test operations in the Soviet piloted lunar landing program. N1 development began in 1962 after two years of initial R&D on heavy booster designs. Although the first launch had been originally planned for 1965, a major redesign of the booster in 1964 and financial and organizational difficulties delayed the launch by four years. The Soviet Communist Party and government officially sanctioned the human lunar landing program in August 1964, more than three years after President John F. Kennedy's famous speech calling on the United States to land an American on the Moon before the end of the 1960s. Development of both the N1 rocket and the L3 payload was plagued by many delays. On this first launch, the N1 carried a basic 7K-L1 spacecraft modified for operations in lunar orbit (rather than for circumlunar flight). Known as the 7K-L1S, the spacecraft was equipped with an Engine Orientation Complex (DOK) for attitude control in lunar orbit. The plan was for the spacecraft to carry out a short mission in lunar orbit (during which time it would have tried to photograph the Ye-8 rover on the surface).
Scientific Instruments:
Lander:
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- MDDA altimeter
-
- G-8 and G-10 gas analyzers
-
- TPV densitometer and thermometer
-
- barometer
Bus:
-
- SG-59M triaxial magnetometer
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- 4 ion traps
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- STS-5 gas discharge counter
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- radiation detectors
-
- SBT-9 gas discharge counter
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- KS-18-2M cosmic ray particle counters
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- LA-2 spectrometer
Results: This identical twin craft to Venera 4 failed to leave Earth orbit when its Blok VL trans-interplanetary stage failed to fire, because the engine's turbopump had not been cooled prior to ignition. The spacecraft remained stranded in Earth orbit and reentered on 25 June 1967.
the surface, the one that had failed to reach orbit just two days earlier). During the launch of the N1, two first stage engines (of a total of 30 NK-15 engines) shut down, but the remaining 28 engines operated for over a minute despite a growing fire at the base of the rocket. The rocket's KORD control system effectively shut down all first state engines at T+70 seconds. The booster crashed about 50 kilometers from the launch site and the payload successfully used its launch escape system to descend without problem 32–35 kilometers from the pad. Investigators believed that booster failed when a pipe for measuring fuel pressure broke at T+23.3 seconds that set in motion a sequence of events that led to a huge fire at T+54.5 seconds in the tail of the first stage. The fire short-circuited the control system and shut down all the engines at T+70 seconds.
Mariner VI
Nation: USA (45)
Objective(s): Mars flyby
Spacecraft: Mariner-69F / Mariner-F
Spacecraft Mass: 381 kg
Mission Design and Management: NASA / JPL
Launch Vehicle: Atlas Centaur (AC-20 / Atlas 3C no. 5403C / Centaur D-1A)
Launch Date and Time: 25 February 1969 / 01:29:02 UT
Launch Site: Cape Kennedy / Launch Complex 36B
Scientific Instruments:
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- imaging system (two TV cameras)
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- infrared spectrometer
-
- ultraviolet spectrometer
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- infrared radiometer
-
- celestial mechanics experiment
-
- S-band occultation experiment
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- conical radiometer
The trajectory design model shown above allowed Mariner mission planners in 1967 to illustrate the orientation of the planet and calculate the expected path of the Mariner VI and VII spacecraft, as well as the window of opportunity for the instruments and television cameras to operate during the flyby. Credit: NASA
Results: Mariner VI and VII, identical spacecraft intended to fly by Mars, were the first Mariner spacecraft launched by the Atlas Centaur, permitting a heavier instrument suite. Both spacecraft were intended to study the surface and atmosphere of Mars during close flybys (approximately 3,200 kilometers) that would include a radio-occultation experiment. All onboard instrumentation was designed to collect data on Mars; there were no experiments for study of interplanetary space. The 3.35-meter tall spacecraft was built around an eight-sided magnesium framework with four rectangular solar panels for 449 W power. The heart of the spacecraft was the 11.8-kilogram Control Computer and Sequencer (CC&S) computer which was designed to independently operate Mariner without intervention from ground control. After a mid-course correction on 28 February 1969 and preliminary imaging sessions (50 photos) on 28 July Mariner VI flew by Mars at 05:19:07 UT on 31 July at a distance of 3,429 kilometers. Just 15 minutes prior to closest approach (south of the Martian equator), the two TV cameras on a scan platform began taking photos of the planet automatically every 42 seconds. Mariner VI took 24 near-encounter photos during a period of 17 minutes which were stored on a tape recorder and later transmitted back to Earth some 20 hours after the flyby at a rate of one frame every 5 minutes. The photos showed heavily cratered and chaotic areas not unlike parts of the Moon. Images of the south polar region showed intriguing detail of an irregular border. The scientific instruments indicated that the polar cap gave off infrared radiation consistent with solid carbon dioxide. Mariner VI found surface pressure to be equal to about 30.5 kilometers above Earth's surface. Atmospheric composition was about 98% carbon dioxide. Surface temperatures ranged from –73°C at night to –125°C at the south polar cap. Mariner VI eventually entered heliocentric orbit (1.14 × 1.75 AU) and NASA continued to receive data from the vehicle until mid-1971.
[Mars, M-69 no. 521]
Nation: USSR (62)
Objective(s): Mars orbit
Spacecraft: M-69 (no. 521)
Spacecraft Mass: 4,850 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Proton-K + Blok D (8K82K no. 240-01 + 11S824 no. 521L)
Launch Date and Time: 27 March 1969 / 10:40:45 UT
Launch Site: NIIP-5 / Site 81/23
Scientific Instruments:
-
- RA69 radiometer
-
- IV1 instrument to measure water vapor levels
-
- USZ ultraviolet spectrometer
-
- UTV1 infrared Fourier spectrometer
-
- KM69 cosmic ray detector
-
- PL18M solar plasma spectrometer
-
- RIP-803 low-energy spectrometer
-
- GSZ gamma-ray spectrometer
-
- UMR2M hydrogen/helium mass spectrometer
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- imaging system (3 cameras)
-
- D-127 charged particle traps
Results: The M-69 series of Mars spacecraft was the first of a new generation of Mars probes designed by the Lavochkin design bureau for launch on the heavy Proton booster. Although the 1969 missions were originally meant for both Mars orbit and landing, weight constraints late in mission planning forced engineers to delete the lander and retain only the orbiter. These new probes were designed around a single large spherical tank to which three pressurized compartments were attached. After two en route mid-course corrections during a six-month flight to Mars, the spacecraft were intended to enter orbit around Mars at roughly 1,700 × 34,000 kilometers at 40° inclination. After an initial photography mission, the probes would lower their pericenter to about 500–700 kilometers for a second imaging mission. Total mission lifetime would be about three months. During the launch of the first M-69, the Proton's third stage stopped firing at T+438.46 seconds after its turbopump had caught on fire because of a faulty rotor bearing. The probe, scheduled to reach Mars orbit on 11 September 1969, never even reached Earth orbit.