91
[Zond, 7K-L1 no. 5L]
Nation: USSR (50)
Objective(s): circumlunar flight
Spacecraft: 7K-L1 (no. 5L)
Spacecraft Mass: c. 5,375 kg
Mission Design and Management: TsKBEM
Launch Vehicle: Proton-K + Blok D (8K82K no. 230-01 / 11S824 no. 13L)
Launch Date and Time: 22 November 1967 / 19:07:59 UT
Launch Site: NIIP-5 / Site 81/24
Scientific Instruments: [unknown]
Results: This was the second Soviet attempt at a robotic circumlunar mission as part of a larger project to send cosmonauts around the Moon. On this launch, one of the four second stage engines of the Proton-K rocket failed to ignite at T+125.5 seconds due to a break in the engine nozzle. The wayward booster was then destroyed on command from the ground at T+129.9 seconds. Once again, the emergency rescue system was activated, shooting the 7K-L1 descent module away from the rocket. The capsule landed by parachute about 80 kilometers southwest of the town of Dzhezkazgan. The actual impact was a hard one because of a spurious command from the altimeter which fired the capsule's soft-landing engines at an altitude of 4.5 kilometers instead of a few meters above the ground.
92
Pioneer VIII
Nation: USA (42)
Objective(s): heliocentric orbit
Spacecraft: Pioneer-C
Spacecraft Mass: 65.36 kg
Mission Design and Management: NASA / ARC
Launch Vehicle: Thrust-Augmented Thor-Delta (Thor Delta E-1 no. 55 / Thor no. 489 / DSV-3E)
Launch Date and Time: 13 December 1967 / 14:08 UT
Launch Site: Cape Kennedy / Launch Complex 17B
Scientific Instruments:
-
- single-axis fluxgate magnetometer
-
- plasma analyzer
-
- cosmic ray telescope
-
- radio-wave propagation experiment
-
- cosmic ray gradient detector
-
- electric field detector
-
- cosmic dust detector
-
- celestial mechanics experiment
Results: Pioneer VIII, like its two predecessors, was sent into heliocentric orbit to study interplanetary space, particularly to collect information on magnetic fields, plasma, and cosmic rays for two or more passages of solar activity. Although the spacecraft carried a different complement of scientific instruments than Pioneers VI and VII, its findings were correlated with the other two probes. The spacecraft was launched into a path ahead of Earth to provide the vehicle with added velocity in solar orbit to move out beyond Earth's orbit at 1.0080 × 0.9892 AU. Pioneer VIII arrived at Earth's magnetospheric bounds at 19:00 UT on 15 December 1967. Later, on 18 January 1968, the probe, the Sun, and Earth were perfectly aligned to allow investigation of Earth's magnetic tail in detail, first performed by Pioneer VII in 1968. Already by June 1968, data from the probe led scientists to speculate that Earth's magnetic tail might be shorter than the 320 million kilometers suggested by theoretical calculations. In August of the same year, NASA scientists at the Deep Space Network (DSN) announced that they had managed to quadruple the distance over which signals from the three solar Pioneers so far launched could be heard. These improvements were enabled by changes in the DSN receivers. In October 1982, Pioneers VIII and IX came within 2.4 million kilometers of each other, an "encounter" used to recalibrate Pioneer VIII's damaged plasma instrument. Controllers intermittently maintained contact with the spacecraft for nearly 30 years although only one instrument, the electric field detector, remained operational past 1982. During tracking on 23 July 1995, NASA was unable to switch on Pioneer VIII's transmitter, probably because the spacecraft was too far away from the Sun to charge the solar panels. On 22 August 1996, contact was reacquired via a backup transmitter. Although there were no further plans to contact the spacecraft, the on-board electric field detector remained at least hypothetically functional in 2015, nearly 48 years after launch. The original launch vehicle also carried a second payload, the Tts I (Test and Training Satellite I, later renamed Tetr I), fixed to the second stage, which was successfully ejected after the third stage finished firing, and entered an Earth orbit of 488 × 301 kilometers at 33° inclination. It reentered on 14 May 1968.
93
Surveyor VII
Nation: USA (43)
Objective(s): lunar soft-landing
Spacecraft: Surveyor-G
Spacecraft Mass: 1,040.1 kg
Mission Design and Management: NASA / JPL
Launch Vehicle: Atlas Centaur (AC-15 / Atlas 3C no. 5903C / Centaur D-1A)
Launch Date and Time: 7 January 1968 / 06:30:00 UT
Launch Site: Cape Kennedy / Launch Complex 36A
Scientific Instruments:
-
- TV camera
-
- alpha-scattering instrument
-
- surface sampler
-
- footpad magnets
-
- stereoscopic and dust detection mirrors
Results: Since Surveyors I, III, V, and VI successfully fulfilled requirements in support of Apollo, NASA opted to use the last remaining Surveyor for a purely scientific mission outside of a potential landing site for the early Apollo flights. After an uneventful coast to the Moon (including one of two planned mid-course corrections), Surveyor VII successfully set down at 01:05:36.3 UT on 10 January 1968 on the ejecta blanket emanating from the bright Tycho crater in the south of the nearside. Landing coordinates were 40.97° S / 11.44° W, about 29 kilometers north of Tycho's rim, and 2.4 kilometers from its target. Initial photos from the surface showed surprisingly few craters, much like the mare sites, although the general area was rougher. About 21 hours after landing, ground controllers fired pyrotechnic charges to drop the alpha-scattering instrument on the lunar surface. When the instrument failed to move beyond an intermediate position, controllers used the surface sampler (robot arm) to force it down. The sampler was then used to pick up the alpha-scattering instrument after its first chemical analysis and move it to two additional locations. About 66 hours of alpha-scattering data were obtained during the first lunar day on three samples: the undisturbed lunar surface, a Moon rock, and an area dug up by the surface sampler. The alpha-scattering instrument collected 34 more hours of data during the second lunar day. The scoop on the sampler's arm was used numerous times for picking up soil and digging trenches, and for conducting at least 16 surface-bearing tests. Apart from taking 21,274 photographs (20,993 on the first lunar day and 45 during the second), Surveyor VII also served as a target for Earth-based lasers (of 1 watt power) to accurately measure the distance between Earth and the Moon. Communications were paused with Surveyor VII at 14:12 UT on 26 January 1968, about 80 hours after sunset. Second lunar day operations began at 19:01 UT on 12 February 1968, and extended to 00:24 UT on 21 February effectively ending the mission. In total, the five successful Surveyors returned more than 87,000 photos of the lunar surface and operated for about 17 months total on the lunar surface, and most important, demonstrated the feasibility of soft-landing a spacecraft on the lunar surface. Originally planned as a 7-spacecraft series, in 1963, NASA added 3 more missions (Surveyors H, I, and J) for a total of 10 missions. These later Surveyors, each weighing 1,134 kilograms (as opposed to the 998-kilogram model), were, however, canceled in December 1966 based on the successful results of the Ranger missions, Lunar Orbiters, and Surveyors already launched by then.
<!-- image -->94
[Luna, Ye-6LS no. 112]
Nation: USSR (51)
Objective(s): lunar orbit
Spacecraft: Ye-6LS (no. 112)
Spacecraft Mass: 1,640 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Molniya-M + Blok L (8K78M no. Ya716-57, also Ya15000-57)
Launch Date and Time: 7 February 1968 / 10:43:54 UT
Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
-
- SL-2 radiometer
-
- IK-2 dosimeter
Results: During launch to Earth orbit, the third stage (Blok I) engine cut off prematurely at T+524.6 seconds because of an excessive propellant consumption rate via the gas generator. The spacecraft never reached Earth orbit. The goal of the mission was to test communications systems in support of the N1-L3 human lunar landing program. (For more details, see Kosmos 159 on p. 67).
95
Zond 4
Nation: USSR (52)
Objective(s): deep space mission
Spacecraft: 7K-L1 (no. 6L)
Spacecraft Mass: c. 5,375 kg
Mission Design and Management: TsKBEM
Launch Vehicle: Proton-K + Blok D (8K82K no. 231-01 + 11S824 no. 14L)
Launch Date and Time: 2 March 1968 / 18:29:23 UT
Launch Site: NIIP-5 / Site 81/23
Scientific Instruments: [unknown]
Results: The Soviets decided to send this next 7K-L1 spacecraft not on a circumlunar flight, but to about 330,000 kilometers into deep space in the opposite direction of the Moon in order to test the main spacecraft systems without the perturbing effects of the Moon, much like the Surveyor model test flights in 1965–1966. After returning from its high apogee, the spacecraft would carry out a high-speed reentry into Earth's atmosphere and be recovered and investigated for the effects of reentry. After launch into Earth orbit, at T+71 minutes and 56 seconds, the Blok D upper stage fired a second time (for 459 seconds) to send the 7K-L1 on a highly elliptical Earth orbit with an apogee of 354,000 kilometers. The Soviet news agency TASS publicly named the spacecraft "Zond 4," thus connecting the mission with a series of completely unrelated deep space probes—a typically obfuscating maneuver from the Soviet media. Controllers were unable to carry out a mid-course correction at 04:53 UT on 4 March when a star sensor (the 100K) of the attitude control system failed. A second attempt also failed the following day and the main omni-directional antenna also did not deploy fully, compromising communications. A third attempt at a correction proved successful, by using a special filter on the sensor to read signals accurately. After the spacecraft separated into its two constituent parts, however, the descent module was unable to maintain a stable and proper attitude for a guided reentry, instead moving into a ballistic reentry trajectory, entering the atmosphere at 18:18:58 UT on 9 March. A crew on board would have experienced about 20 g's but probably would have survived. However, because the descent module was falling into an unanticipated area, to prevent "foreign" observers from recovering the wayward spacecraft, an automatic emergency destruct system destroyed the returning capsule at an altitude of 10–15 kilometers over the Gulf of Guinea. For some years, the official Soviet press claimed that Zond 4 had entered heliocentric orbit.
Luna 14
Nation: USSR (53)
Objective(s): lunar orbit
Spacecraft: Ye-6LS (no. 113)
Spacecraft Mass: 1,640 kg
Mission Design and Management: GSMZ imeni Lavochkina
Launch Vehicle: Molniya-M + Blok L (8K78M no. Ya716-58, also Ya15000-58)
Launch Date and Time: 7 April 1968 / 10:09:32 UT
Launch Site: NIIP-5 / Site 1/5
Scientific Instruments:
-
- SL-2 radiometer
-
- IK-2 dosimeter
Results: Luna 14 successfully entered lunar orbit at 1925 UT on 10 April 1968. Initial orbital parameters were 160 × 270 kilometers at 42° inclination. The primary goal of the flight, like its predecessors (Kosmos 159 and the launch failure in February 1968), was to test communications systems in support of the N1-L3 piloted lunar landing project. In addition, ground tracking of the spacecraft's orbit allowed controllers to accurately map lunar gravitational anomalies to predict future trajectories of future lunar missions such as those of the LOK and LK lunar landing vehicles. Luna 14 also carried scientific instruments to measure radiation near the Moon, a "tissue dosimeter for studying doses of ionizing radiation," as well as technical elements of the future Ye-8 lunar rover, in particular, the R-1-I, R-1-II, and R-1-III gear pairs (both steel and ceramic), various types of ball bearings with lubrication to test drives, and the M-1 drive shaft. The mission was slated to last 30 days but spanned 75 days; the entire program was fulfilled as planned, and allowed designers to make the final selection for elements of the Ye-8 lunar rover chassis.