79
Surveyor III
Nation: USA (34)
Objective(s): lunar soft-landing
Spacecraft: Surveyor-C
Spacecraft Mass: 997.9 kg
Mission Design and Management: NASA / JPL
Launch Vehicle: Atlas Centaur (AC-12 / Atlas D no. 292 / Centaur D)
Launch Date and Time: 17 April 1967 / 07:05:01 UT
Launch Site: Cape Kennedy / Launch Complex 36B
Scientific Instruments:
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- TV camera
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- surface sampler
Results: Surveyor III was the third engineering flight of the series, but for the first time carried a surface-sampling instrument that could reach up to 1.5 meters from the lander and dig up to 18 centimeters deep. Unlike the previous Surveyors, Surveyor III began its mission from parking orbit around Earth with a burn from the Centaur upper stage, now capable of multiple firings. During the descent to the lunar surface, highly reflective rocks confused the lander's descent radar, and the main engine failed to cut off at the correct moment at about 4.3-meters altitude. As a result, Surveyor III bounced off the lunar surface twice, the first time to a height of 10 meters and the second time, to 3 meters. The third time, the lander settled down to a soft-landing at 00:04:17 UT on 20 April 1967 in the south-eastern region of Oceanus Procellarum at 3.0° S / 23.41° W. Less than an hour after landing, the spacecraft began transmitting the first of 6,326 TV pictures of the surrounding areas. The most exciting experiments of the mission included deployment of the surface sampler for digging trenches, making bearing tests, and manipulating lunar material in the view of the TV system. Via commands from Earth, it dug four trenches, and performed four bearing tests and thirteen impact tests. Based on these experiments, scientists concluded that lunar soil had a consistency similar to wet sand, with a bearing strength of 0.7 kilograms/cm², i.e., solid enough for an Apollo Lunar Module. The lander's TV camera consisted of two 25 and 100 mm focal length lenses and was mounted under a mirror that could be moved horizontally and vertically. It took about 20 seconds to transmit a single 200-line picture of the surface. The camera was also capable of 600-line images which used digital picture transmission. Last contact was made on 4 May 1967, two days after the lunar night began. More than three years later, on 18 November 1969, Apollo 12 astronauts Charles Conrad, Jr. and Alan L. Bean landed the Intrepid Lunar Module approximately 180 meters from the inactive Surveyor III lander. During their second extra-vehicular activity (EVA) on 19 November, the astronauts walked over to Surveyor III and recovered parts, including the soil scoop and camera system, to allow scientists to evaluate the effects of nearly two-and-a-half years of exposure on the Moon's surface.
80
Lunar Orbiter IV
Nation: USA (35)
Objective(s): lunar orbit
Spacecraft: LO-D (Spacecraft 7)
Spacecraft Mass: 385.6 kg
Mission Design and Management: NASA / LaRC
Launch Vehicle: Atlas Agena D (Atlas Agena D no. 22 / Atlas D no. 5804 / Agena D no. AD131/6633)
Launch Date and Time: 4 May 1967 / 22:25:00 UT
Launch Site: Cape Kennedy / Launch Complex 13
Scientific Instruments:
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- imaging system
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- micrometeoroid detectors
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- radiation dosimeters
Results: Lunar Orbiter IV was the first in the series dedicated to scientific surveys of the Moon. Its goal was to acquire contiguous photographic coverage of the lunar surface of at least 80% of the near side at 50–100-meter resolution. After a midcourse correction on 5 May 1967, Lunar Orbiter IV fired its engine at 15:08 UT on 8 May to insert the spacecraft into an initial lunar polar orbit of 6,111 × 2,706 kilometers at 85.5° inclination, thus becoming the first spacecraft to go into polar orbit around the Moon. Orbital period was about 12 hours. The spacecraft began its photographic mission at 15:46 UT on 11 May. A potentially serious problem threatened the mission when on 13 May, controllers found a problem with a camera thermal door that failed to close, leaking light onto exposed images. They were able to devise a fix that worked and the spacecraft continued its imaging mission. During its two-month mission, Lunar Orbiter IV took pictures of 99% of the near side and 75% of the farside of the Moon in a total of 163 frames. The imaging mission ended on the orbiter's 34th orbit due to worsening readout difficulties. Fortunately, all but 30 of the 163 images collected, many with a resolution down to 60 meters, were successfully transmitted to Earth by 1 June. In early June, controllers lowered the spacecraft's orbit to match that of Lunar Orbiter V so that scientists could collect gravitational data in support of the latter mission. Before losing contact on 17 July, Lunar Orbiter IV took the first photos of the lunar south pole and discovered a 240-kilometer long crustal fault on the farside. Since contact was lost before controlled impact, the spacecraft naturally crashed onto the Moon on 6 October 1967 due to gravitational anomalies.
81
Kosmos 159 [Luna]
Nation: USSR (46)
Objective(s): highly-elliptical orbit around Earth
Spacecraft: Ye-6LS (no. 111)
Spacecraft Mass: 1,640 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Molniya-M + Blok L (8K78M no. Ya716-56, also N15000-56)
Launch Date and Time: 16 May 1967 / 21:43:57 UT
Launch Site: NIIP-5 / Site 1/5
Scientific Instruments: [none]
Results: This spacecraft was a one-off high apogee Earth satellite developed to acquire data on new telecommunications systems for upcoming crewed missions to the Moon. Besides a usual complement of telemetry and communications equipment, the vehicle also carried a transceiver as part of the long-range communications system (Dal'nyy radiokompleks, DRK) and the BR-9-7 telemetry system, equipment designed to work with the new Saturn-MS-DRK ground station located near the village of Saburovo, about 10 kilometers from NIP-14, a station, close to Moscow, belonging to the Soviet ground-based tracking network. The spacecraft was similar to Luna 11 but had a slightly lengthened (by 15 cm) instrument container so as to accommodate the modified DRK and new BR-9-7 telemetry systems. Mission designers had planned to send the probe into a highly elliptical orbit with an apogee of 250,000 kilometers, but the Blok L upper stage cut off too early. Instead, the spacecraft, named Kosmos 159, entered a lower orbit of 380 × 60,600 kilometers at 51.5° inclination. Despite the incorrect orbit, controllers were able to accomplish the original mission, carried out over a period of nine days during which it was discovered that the energy potential of the UHF downlink from the spacecraft to the ground was 1–2 orders magnitude below the calculated value. Kosmos 159 reentered Earth's atmosphere on 11 November 1967.
82
Venera 4
Nation: USSR (47)
Objective(s): Venus impact
Spacecraft: V-67 (1V no. 310)
Spacecraft Mass: 1,106 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Molniya-M + Blok VL (8K78M no. Ya716-70, also Ya15000-70)
Launch Date and Time: 12 June 1967 / 02:39:45 UT
Launch Site: NIIP-5 / Site 1/5
A model of the 1-meter diameter landing capsule of Venera 4 on display at the Memorial Museum of Cosmonautics in Moscow. Credit: Asif Siddiqi
<!-- image -->Scientific Instruments:
Lander:
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- MDDA altimeter
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- G-8 and G-10 gas analyzers
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- TPV densitometer and thermometer
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- barometer
Bus:
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- 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
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- SBT-9 gas discharge counter
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- KS-18-2M cosmic ray particle counters
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- LA-2 spectrometer
Results: Venera 4 was the first spacecraft to transmit data from a planet's atmosphere. It was also the first Venus probe built by the Lavochkin design bureau, although Lavochkin engineers retained the basic design layout of the earlier 3MV probes built under Chief Designer Sergey Korolev (1907–1966). The spacecraft consisted of a main bus about 3.5 meters high and a 383-kilogram lander probe designed to transmit data as it descended through the Venusian atmosphere. This capsule could endure loads as high as 300 g's and land on both land and liquid. For atmospheric entry it was equipped with a thick ablative heatshield. Launch, for the first time, used an upgraded Blok L (4th stage), the Blok VL. After a mid-course correction on 29 July 1967, Venera 4 approached Venus on 18 October. About 2 hours before arrival at Venus, at a distance of 45,000 kilometers, on command from Earth, the spacecraft was properly oriented for entry. The bus released the lander at 04:34 UT, and the latter entered the Venusian atmosphere at a velocity of 11 kilometers/second. The bus returned data for some time before being destroyed in the atmosphere. The lander, meanwhile experienced as much as 300 g's and reduced its speed to 210 meters/second at which point the parachute system was deployed. Simultaneously, the lander began to transmit information back to Earth. Because the altimeter was designed to record pressures only up to 7.3 atmospheres, it went off-scale rather quickly. Temperature measurements (from 33°C to 262°C) continued to come back for 93 minutes as the probe slowly descended through the atmosphere. Initially, Soviet scientists believed that the probe transmitted until contact with the surface, announcing that "a calculation of the rate of descent of the station until termination of transmission of data indicates that it continued transmitting until it actually touched the surface of the planet." Later analysis of data showed that transmissions ceased at an altitude of 28 kilometers when the high atmospheric pressure and temperatures damaged the probe. The inert probe impacted the surface near 19° N / 36° E. The data implied that surface temperatures and pressure were 500°C and 75 atmospheres respectively. Venera 4's gas analyzers also found that the planet's atmosphere was composed of 90–95% carbon dioxide (with a sensitivity of ±7%) with no nitrogen, which had previously been assumed would constitute most of the atmosphere. Data from the ionizing densitometer showed that cloud cover in the Venusian atmosphere exists at altitudes below 52 kilometers with the lower boundary at roughly 35 kilometers. The spacecraft bus measured the planet's weak magnetic field and found no ring of radiation belts. It detected a very weak atmosphere of atomic hydrogen about 9,900 kilometers above the planet. Noteworthy was Venera 4's detection of the planet's bow shock, identified a day before by Mariner V (and later confirmed by Venera 5). The mission's importance was underscored when NASA Administrator James E. Webb (1906–1992) issued a statement on 18 October 1967, noting that the landing "represents an accomplishment any nation can be proud of." Researchers at NASA Ames Research Center were particularly interested in data from Venera 4, especially the effect of planetary atmosphere on the propagation of radio signals from the spacecraft, in anticipation of future NASA missions to Venus.
83
Mariner V
Nation: USA (36)
Objective(s): Venus flyby
Spacecraft: Mariner-67E / Mariner-E
Spacecraft Mass: 244.9 kg
Mission Design and Management: NASA / JPL
Launch Vehicle: Atlas Agena D (Atlas Agena D no. 23 / Atlas D no. 5401 / Agena D no. AD157/6933)
Launch Date and Time: 14 June 1967 / 06:01:00 UT
Launch Site: Cape Kennedy / Launch Complex 12
Scientific Instruments:
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- ultraviolet photometer
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- S-band occultation experiment
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- dual frequency occultation experiment
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- solar plasma probe
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- magnetometer
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- trapped radiation detector
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- celestial mechanics experiment
Results: In December 1965, NASA approved a project to modify the Mariner IV backup spacecraft to conduct a closer flyby of Venus than the only other NASA probe to fly past Venus, Mariner II. The primary goal of the mission was to conduct a radio-occultation experiment (much like Mariner IV at Mars) to determine atmospheric properties of Venus. Unlike Mariner IV, however, Mariner V did not carry an imaging instrument. Initially, NASA had planned to send Mariner V on a flyby at a miss distance of 8,165 kilometers to the surface, but the Agency altered its plan in favor of a more modest 75,000-kilometer flyby in order to preclude the non-sterilized vehicle from crashing into the planet. After a mid-course correction on 19 June, Mariner V began transmitting data on Venus on 19 October during its encounter. Closest approach was at 17:34:56 UT at a range of 4,094 kilometers, much closer than expected due to the course correction. Mariner V found that although Venus does not have a magnetic field, the dense daylight ionosphere produces a bow shock that deflects the solar wind around the planet. The ultraviolet photometer detected a hydrogen corona (as found by the Soviet Venera 4) but no oxygen emission. Mariner V's instruments indicated that the planet's surface temperature and pressure were 527°C and 75 to 100 atmospheres, respectively—which countered the Soviet claim that its Venera 4 spacecraft had managed to transmit from the planet's surface. The encounter with Venus deflected the spacecraft towards the Sun, and Mariner V entered solar orbit with parameters ranging from 0.579 AU and 0.735 AU. On 4 December 1967, NASA lost contact with the spacecraft although controllers briefly regained contact on 14 October 1968. The spacecraft did not transmit any further telemetry and NASA eventually stopped attempts (on 5 November 1968) to communicate with the vehicle, now in heliocentric orbit. Planetary scientists reviewed data from both Mariner V and the Soviet Venera 4 at a conference at Kitt Peak National Observatory in March 1968, one of the first major international meetings to discuss the results of planetary exploration. Scientists concluded that neither Mariner V or Venera 4 had been entirely successful in communicating data about conditions at the planet's surface.