Beyond_Earth-_A_Chronicle_of_Deep_Space_Exploration_1958-2016.pdf

Venera 8

Nation: USSR (82)

Objective(s): Venus landing

Spacecraft: V-72 (3V no. 670)

Spacecraft Mass: 1,184 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Molniya-M + Blok NVL (8K78M no. S1500-63)

Launch Date and Time: 27 March 1972 / 04:15:06 UT

Launch Site: NIIP-5 / Site 31/6

Scientific Instruments:

Spacecraft Bus:

• 1. KS-18-4M cosmic ray detector

Lander:

• 1. thermometers and barometers (ITD)
• 2. IOV-72 photometers
• 3. GS-4 gamma-ray spectrometer
• 4. IAV-72 gas (ammonia) analyzer
• 5. DOU-1M accelerometer
• 6. radar altimeter

Results: Venera 8 was the first in new pair of Soviet spacecraft designed to explore Venus. Although similar in design to its predecessors, the 495-kilogram lander was substantially modified, based on the results from Venera 7. Lavochkin Chief Designer Sergey Kryukov noted in an interview in Pravda on 5 August 1972 that "Venera 8 was a logical continuation of the previous Venera 7" but "the construction of the descent vehicle was almost completely new." The new capsule was designed to withstand pressures of "only" 105 atmospheres (versus 150 atmospheres on Venera 7) and 493°C (instead of 540°C), had an upgraded parachute system, and carried extra scientific instrumentation. After one mid-course correction on 6 April 1972, Venera 8's lander separated from the flyby bus at 07:40 UT on 22 July 1972 and entered the Venusian atmosphere 57 minutes later at a velocity of 11.6 kilometers/second. During the aerodynamic breaking segment, the descent module reduced its velocity from 11.6 kilometers/second to 250 meters/second, thus surviving a maximum g-force of 335; the gas temperature in the shock wave at the "front" of the vehicle was more than 12,000°C. Successful landing took place at 09:29 UT about 500 kilometers from the morning terminator on the sunlit side of Venus, the first such landing. Landing coordinates were a 10-mile radius of 10.7° S / 335.25° E. The probe transmitted data for another 50 minutes, 11 seconds from the hostile surface before succumbing to ground conditions. The transmitted information indicated that temperature and pressure at the landing site were 470±8°C and 90±1.5 atmospheres respectively, very close to values obtained on the planet's night side by Venera 7. Wind velocity was less than 1 kilometer/second below 10 kilometers altitude. Data from the gamma-ray spectrometer made it possible to make some determination of naturally occurring radioactive elements in the soil. Preliminary data suggested that the surface material contained 4% potassium, 0.002% uranium, and 0.00065% thorium. The lander answered one of the key questions about the surface of Venus, namely the degree of illumination on the ground. Based on data from the photometer, scientists concluded that "a certain portion of solar rays in the visible region of the spectrum penetrates to the surface of the planet and that there are significant differences in illumination between day and night." The data indicated that visibility on the ground was about one kilometer at the time Venera 8 landed. The spacecraft also recorded a sharp change in illumination between 30 and 35 kilometers altitude.

Kosmos 482 [Venera]

Nation: USSR (83)

Objective(s): Venus landing

Spacecraft: V-72 (3V no. 671)

Spacecraft Mass: c. 1,180 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Molniya-M + Blok NVL (8K78M no. S1500-64)

Launch Date and Time: 31 March 1972 / 04:02:33 UT

Launch Site: NIIP-5 / Site 31/6

Scientific Instruments:

Spacecraft Bus:

• 1. KS-18-4M cosmic ray detector

Lander:

• 1. thermometers and barometers (ITD)
• 2. IOV-72 photometers
• 3. GS-4 gamma-ray spectrometer
• 4. IAV-72 gas (ammonia) analyzer
• 5. DOU-1M accelerometer
• 6. radar altimeter

Results: This was the sister craft to Venera 8, which was launched four days prior. Unfortunately, the spacecraft never left Earth orbit. The Blok NVL escape stage's main engine prematurely cut off after only 125 seconds of firing due to a failure in the onboard timer. As a result, the spacecraft entered an elliptical orbit around Earth. Officially, the Soviets named the probe Kosmos 482 to disguise its true mission. The main spacecraft reentered on 5 May 1981.

Apollo 16 Particles and Fields Subsatellite

Nation: USA (52)

Objective(s): lunar orbit

Spacecraft: Apollo 16 P&FS

Spacecraft Mass: 42 kg

Mission Design and Management: NASA / MSC

Launch Vehicle: Apollo 16 CSM-113 (itself launched by Saturn V SA-511)

Launch Date and Time: 16 April 1972 / 17:54:00 UT (subsatellite ejection on 24 April 1972 / 09:56:09 UT)

Launch Site: Kennedy Space Center / Launch Complex 39A

Scientific Instruments:

• 1. magnetometer
• 2. S-band transponder
• 3. charged particle detectors

Results: Nearly identical to its predecessor, the Apollo 16 Particles and Fields Subsatellite was ejected from the Apollo 16 Command and Service Module about 4 hours prior to the crew's trans-Earth injection burn which sent them home from the Moon. Because of problems with the Apollo CSM main engine, the crew were forced to release the subsatellite in a low lunar orbit of 100 × 100 kilometers at 10° inclination. Thus, the probe eventually crashed onto the lunar surface after 34 days in orbit rather than the planned one year. Impact point was at 10.2° N / 112° E at 21:00 UT on 29 May 1972. Because of its low orbit, the spacecraft did, however, return some valuable low-altitude data.

[N1 launch test, 7K-LOK no. 6A]

Nation: USSR (84)

Objective(s): lunar orbit

Spacecraft: 7K-LOK (no. 6A)

Spacecraft Mass: c. 9,500 kg

Mission Design and Management: TsKBEM

Launch Vehicle: N1 (no. 15007)

Launch Date and Time: 23 November 1972 / 06:11:55 UT

Launch Site: NIIP-5 / Site 110/37

Scientific Instruments:

[unknown]

Results: This was fourth test launch of the giant Soviet N1 booster. The first two, launched in 1969, had attempted to send rigged up 7K-L1 spacecraft to lunar orbit. The third booster, launched in June 1971, had carried a payload mockup for tests in Earth orbit. All three had failed. This fourth launch was intended to send a fully equipped 7K-LOK spacecraft (similar to a beefed-up Soyuz) on a robotic lunar orbiting mission during which the spacecraft would spend 3.7 days circling the Moon (over 42 orbits) taking photographs of future landing sites for piloted missions. The booster lifted off without problems, but a few seconds prior to first stage cutoff, at T+107 seconds, a powerful explosion ripped apart the bottom of the first stage, destroying unequivocally Soviet hopes of sending cosmonauts to the Moon. There was never a conclusive reason for the failure, with some suggesting that there had been an engine failure and others convinced that the scheduled shutdown of six central engines just prior to the explosion had caused a structural shockwave that eventually caused the explosion.

<!-- image -->

Luna 21 and Lunokhod 2

Nation: USSR (85)

Objective(s): lunar roving operations

Spacecraft: Ye-8 (no. 204)

Spacecraft Mass: 5,700 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Proton-K + Blok D (8K82K no. 259-01 + 11S824 no. 205L)

Launch Date and Time: 8 January 1973 / 06:55:38 UT

Launch Site: NIIP-5 / Site 81/23

Scientific Instruments:

• 1. imaging system (three low resolution TV + four high resolution photometers)
• 2. RIFMA-M x-ray fluorescence spectrometer
• 3. PrOP penetrometer
• 4. TL-2 laser reflector (with Rubin-1 photo receiver)
• 5. RV-2N radiation detector
• 6. x-ray telescope
• 7. odometer/speedometer
• 8. AF-3L visible/ultraviolet photometer
• 9. SG-70A tricomponent magnetometer
• 10. photodetector

Results: Luna 21 carried the second successful Soviet "8YeL" lunar rover, Lunokhod 2. Launched less than a month after the last Apollo lunar landing, Luna 21 entered orbit around the Moon on 12 January 1973 (after a single mid-course correction en route). Parameters were 110 × 90 kilometers at 60° inclination. On 15 January, the spacecraft deorbited, and after multiple engine firings, landed on the Moon at 22:35 UT the same day inside the 55-kilometer wide LeMonnier crater at 25° 51′ N / 30° 27′ E (as announced at the time) between Mare Serenitatis and the Taurus Mountains, about 180 kilometers north of the Apollo 17 landing site. Less than 3 hours later, at 01:14 UT on 16 January, the rover disembarked onto the lunar surface. The 840 kilogram Lunokhod 2 was an improved version of its predecessor, and was equipped with two types of television cameras. The first consisted of two vidicon cameras ("small frame television" cameras according to the Soviet media) for transmitting information to help basic navigation control. A second set consisted of four pair-mounted, side-carried panoramic opto-mechanical cycloramic cameras. The rover also included an improved 8-wheel traction system and additional scientific instrumentation, including significantly, a magnetometer. By the end of its first lunar day, 23 January 1973, Lunokhod 2 had already traveled further than Lunokhod 1 in its entire operational life. The main focus of investigations during the second lunar day, which ended on 22 February, was a study of the transitional mare highlands in the southern part of the LeMonnier Crater, including stereoscopic panoramic television imagery of the surface, measurement of the lunar soil's chemical properties, and taking magnetic readings. By this time, the rover had travelled a total of 11.067 kilometers. For the ground "crew" navigating Lunokhod, there were times of high stress, compounded by the time lag between Earth and Moon. Izvestiya reported on 13 March 1973 that at times "crew" members pulses reached 130–135 beats per minute with one individual holding their breath in nervousness for 15–20 seconds. During the fourth lunar day, which began on 9 April, Lunokhod 2 traveled right to the edge of a large tectonic fault in the eastern area of the littoral zone of the LeMonnier Crater, an area that was very difficult to traverse given the proliferation of rocks up to 2–3 meters in size. By the end of the fourth lunar day on 23 April it had travelled 36.2 kilometers. On 9 May the rover was commanded to leave the area of the fault but inadvertently rolled into a crater, with dust covering its solar panels, disrupting temperatures in the vehicle. Attempts to save the rover failed, and on 3 June the Soviet news agency announced that its mission was over. An official internal Soviet report on Lunokhod 2 noted that the rover had "ended its operations" earlier, at 12:25 UT on 10 May 1973, after temperatures had reached up to 43–47°C and on board systems had shut down. All subsequent attempts at contact apparently failed. Before last contact, the rover took 80,000 TV pictures and 86 panoramic photos and had performed hundreds of mechanical and chemical surveys of the soil, including 25 soil analyses with the RIF-MA (Rentgenskiy izotopnyy fluorestsentnyy metod analyiza or x-ray Isotopic Fluorescence Analysis Method) instrument. Despite the formal end of the mission, experiments with the French TL-2 laser reflector continued for decades, and were much more successful than the rangings carried out with the similar instrument on Lunokhod 1. At the time of the Lunokhod 2 mission, scientists calculated a total travel distance of 37.5 kilometers, about three-and-a-half times more than its predecessor. An extended summary of the scientific results from the mission was published in Pravda on 20 November 1973. The Soviets later revealed that during a conference on planetary exploration in Moscow held from 29 January to 2 February 1973 (i.e., after the landing of Luna 21), an American scientist had given photos of the lunar surface around the Luna 21 landing site to a Soviet engineer in charge of the Lunokhod 2 mission. These photos, taken prior to the Apollo 17 landing, were later used by the "driver team" to navigate the new rover on its mission on the Moon. Later, in 2013, based on imagery from the Lunar Reconnaissance Orbiter (LRO), Russian researchers led by Irina Karachevtseva at the Moscow State University's Institute of Geodesy and Cartography (MIIGAiK), recalculated the total distance travelled and came to a more precise number of between 42.1 and 42.2 kilometers. The original landing site location was also sharpened to 25.99° N / 30.41° E.