Beyond_Earth-_A_Chronicle_of_Deep_Space_Exploration_1958-2016.pdf

68

Surveyor Model 2

Nation: USA (26)

Objective(s): highly elliptical orbit

Spacecraft: SD-3

Spacecraft Mass: 784 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Atlas Centaur (AC-8 / Atlas no. 184D / Centaur D)

Launch Date and Time: 8 April 1966 / 01:00:02 UT

Launch Site: Cape Kennedy / Launch Complex 36B

Scientific Instruments: [none]

Results: This was a test to launch a dummy Surveyor lunar lander spacecraft into a barycentric orbit towards a simulated Moon. Unlike the two previous Surveyor mass model tests, this flight was supposed to demonstrate a restart capability for the Centaur upper stage. The Centaur-Surveyor combination successfully achieved parking orbit around Earth (with a first firing), but at the desired time, when it came time for the second firing, the Centaur RL-10 engines fired for only a few seconds (instead of 107 seconds). A thrust imbalance left the payload tumbling and in an incorrect orbit of 182 × 335 kilometers at 30.7° inclination. The problem was later traced to a hydrogen peroxide leak in the ullage motors of the Centaur stage. With no hope of reaching its ultimate orbit (planned for 167 × 380,000 km), the payload reentered on 5 May 1966.

69

Surveyor I

Nation: USA (27)

Objective(s): lunar soft-landing

Spacecraft: Surveyor-A

Spacecraft Mass: 995.2 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Atlas Centaur (AC-10 / Atlas D no. 290 / Centaur D)

Launch Date and Time: 30 May 1966 / 14:41:01 UT

Launch Site: Cape Kennedy / Launch Complex 36A

Scientific Instruments:

1. TV camera

Results: In January 1961, NASA selected Hughes Aircraft Company to build a series of seven soft-landing vehicles, each weighing about 340 kilograms, to "land gently on the moon, perform chemical analyses of the lunar surface and subsurface and relay back to Earth television pictures of lunar features." These vehicles were to be designed and built under the technical direction of JPL and launched in the period of 1963–1966. Unlike the Soviet Luna landers, Surveyor was a true soft-lander, comprising a three-meter tall vehicle based on a 27-kilogram thin-walled aluminum triangular structure with one of three legs at each corner and a large solid-propellant retro-rocket engine (that comprised over 60% of the spacecraft's overall mass) in the center. The spacecraft was equipped with a Doppler velocity-sensing system that fed information into the spacecraft computer to implement a controllable descent to the surface. Each of the three landing pads also carried aircraft-type shock absorbers and strain gauges to provide data on landing characteristics, important for future Apollo missions. Surveyor I, the first in the series, was an unprecedented success. NASA accomplished the first true soft-landing on the Moon on its very first try when the probe landed in the southwestern region of the Ocean of Storms at 06:17:36 UT on 2 June 1966, just 63.6 hours after launch from Cape Canaveral. Touchdown coordinates were announced as 2.46° S / 43.32° W, just 14 kilometers from the planned target. At landing, the spacecraft weighed 294.3 kilograms. The initial panoramic views from the lunar surface indicated that Surveyor I was resting in a 100-kilometer diameter crater that contained boulders more than one meter scattered all around. The photos showed crestlines of low mountains in the distant horizon. The lander transmitted 11,240 high-resolution images over two separate communications sessions by 6 July. Although the primary mission was completed by 14 July, NASA maintained contact until 7 January 1967. Without doubt, Surveyor I was one of the great successes of NASA's early lunar and interplanetary program.

70

Explorer XXXIII

Nation: USA (28)

Objective(s): lunar orbit

Spacecraft: AIMP-D

Spacecraft Mass: 93.4 kg

Mission Design and Management: NASA / GSFC

Launch Vehicle: Thor Delta E-1 (Thor Delta E-1 no. 39 / Thor no. 467/DSV-3E)

Launch Date and Time: 1 July 1966 / 16:02:25 UT

Launch Site: Cape Kennedy / Launch Complex 17A

Scientific Instruments:

• 1. ionizing radiation experiment
• 2. 3-grid Faraday cup / thermal ion experiment
• 3. 3 GM tubes and a PN junction semiconductor / energetic particle experiment
• 4. plasma probe experiment
• 5. magnetometer (from Ames)
• 6. magnetometer (from GSFC)
• 7. solar cell damage experiment

Results: It was hoped that Explorer XXXIII (33), also known as the Anchored Interplanetary Monitoring Platform (AIMP), would become the first U.S. spacecraft to enter lunar orbit (planned parameters were 1,300 × 6,440 kilometers at 175° inclination), but the Thor Delta E-1 second stage accelerated too rapidly, ensuring that lunar orbit would not be possible. Instead mission planners adopted an alternate mission which required the probe's (Thiokol TE-M-458) 35.8 kgf thrust retro-rocket to fire about 6.5 hours after launch. Under the new plan, the spacecraft was put into a highly elliptical Earth orbit of 449,174 × 30,550 kilometers at 28.9° inclination. In this orbit, Explorer XXXIII was high enough to be perturbed by the Moon's gravitation. In its new orbit, Explorer XXXIII approached the Moon (on its very first orbit) to a distance of 35,000 kilometers with subsequent close approaches in September, November, and December 1966 varying from 40,000 to 60,000 kilometers. During this time, the probe returned key data on Earth's magnetic tail, the interplanetary magnetic field, and radiation. In January 1967, Goddard Space Flight Center engineers used an electric "screwdriver" to restore power to the spacecraft after a temporary blackout. The emergency repair was the most remote repair carried out on a spacecraft to date. The mission was declared a success by 1 January 1967, although the spacecraft continued to return useful data until 15 September 1971.

71

Lunar Orbiter I

Nation: USA (29)

Objective(s): lunar orbit

Spacecraft: LO-A

Spacecraft Mass: 386.9 kg

Mission Design and Management: NASA / LaRC

Launch Vehicle: Atlas Agena D (Atlas Agena D no. 17 / Atlas D no. 5801 / Agena D no. AD121/6630)

Launch Date and Time: 10 August 1966 / 19:26:00 UT

Launch Site: Cape Kennedy / Launch Complex 13

Scientific Instruments:

• 1. imaging system
• 2. micrometeoroid detectors
• 3. radiation dosimeters

Results: The Lunar Orbiter program originated as a response to the need to obtain one-meter resolution photographs of potential Apollo landing sites. NASA planned launches of a series of three-axis stabilized spacecraft with four solar panels and a main engine (derived from an Apollo attitude control thruster) for lunar orbit insertion. The primary instrument on board was a 68-kilogram Eastman Kodak imaging system (using wide and narrow-angle lenses) that could develop exposed film, scan them, and send them back to Earth. In a twist that was not known until after the end of the Cold War, the Eastman Kodak camera flown on the Lunar Orbiters was originally developed by the National Reconnaissance Office (NRO) and flown on the Samos E-1 spy satellite. The narrow-angle pictures taken by this system provided resolution up to 60 to 80 meters, while the wide-angle photos showed resolutions up to 0.5 kilometers. Lunar Orbiter I was launched into a parking orbit around Earth before its Agena upper stage fired at 20:04 UT to insert it on a translunar trajectory. On the way to the Moon, the spacecraft's Canopus star tracker failed to acquire its target, probably because the spacecraft's structure was reflecting too much light. Flight controllers used a backup method by using the same sensor, but with the Moon to orient the vehicle. The vehicle also displayed higher than expected temperatures but successfully entered a 1,866.8 × 189.1-kilometer orbit around the Moon on 24 August, thus becoming the first U.S. spacecraft to do so. The spacecraft's primary mission was to photograph nine potential Apollo landing sites, seven secondary areas, and the Surveyor I landing site. By 28 August, Lunar Orbiter I had completed its main photography mission, having exposed a total of 205 frames, of which 38 were taken in the initial orbit and 167 in lower orbits, covering an area of 5.18 million km². As planned, it photographed all 9 potential Apollo landing sites as well as 11 sites on the far side of the Moon. Some of the high-resolution photos were blurred due to smearing (stemming from problems in the imaging system), but the medium resolution images were the best lunar surface images returned to date. One of the images returned, unplanned but taken on 23 August, was the first picture of Earth taken from the vicinity of the Moon. Lunar Orbiter I began an extended non-photography phase of its mission on 16 September that was focused on engineering goals, but by 28 October, the spacecraft's condition had deteriorated. As such, the day after, on its 577th orbit, ground controllers commanded the orbiter to crash onto the lunar surface (at 13:30 UT) to prevent its transmissions from interfering with future Lunar Orbiters. Impact coordinates were 6° 42′ N / 162° E.

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Pioneer VII

Nation: USA (30)

Objective(s): heliocentric orbit

Spacecraft: Pioneer-B

Spacecraft Mass: 62.75 kg

Mission Design and Management: NASA / ARC

Launch Vehicle: Thrust Augmented Improved Delta (Thor Delta E-1 no. 40 / Thor no. 462/DSV-3E)

Launch Date and Time: 17 August 1966 / 15:20:17 UT

Launch Site: Cape Kennedy / Launch Complex 17A

Scientific Instruments:

• 1. single-axis fluxgate magnetometer
• 2. plasma Faraday cup
• 3. electrostatic analyzer
• 4. cosmic ray telescope
• 5. cosmic ray anisotropy detector
• 6. two-frequency beacon receiver

Results: Identical to Pioneer VI, Pioneer VII was put into heliocentric orbit at 1.01 × 1.125 AU with a period of 402.95 days to study magnetic fields of solar origin, measure various characteristics of the solar wind, and distinguish between solar and galactic cosmic rays. On 17 August 1966, Pioneer VII flew through Earth's magnetic tail region at 5.6 million kilometer range from Earth, and discovered long periods when the solar wind was completely or partially blocked out, suggesting that its instruments were monitoring the end of an organized tail region. On 7 September 1968, the spacecraft was correctly aligned with the Sun and Earth to begin studying Earth's magnetic tail. In 1977, 11 years after its launch, Pioneer VII registered the magnetic tail 19.3 million kilometers out, three times further into space than recorded prior. At 23:36 UT, on 20 March 1986, the spacecraft flew within 12.1 million kilometers of Halley's Comet—the closest a U.S. spacecraft approached the comet—and monitored the interaction between the cometary hydrogen tail and the solar wind. Like Pioneer VI and Pioneer VIII, NASA maintained intermittent contact with Pioneer VII in the 1990s, more than 30 years after its mission began (with data returned from its cosmic ray detector and plasma analyzer in February 1991, for example). On 31 March 1995, the plasma analyzer was turned on during 2 hours of contact with the ground, this being the final contact made with the spacecraft.

73

Luna 11

Nation: USSR (43)

Objective(s): lunar orbit

Spacecraft: Ye-6LF (no. 101)

Spacecraft Mass: 1,640 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Molniya-M + Blok L (8K78M no. N103-43, also N15000-52)

Launch Date and Time: 24 August 1966 / 08:03:21 UT

Launch Site: NIIP-5 / Site 31/6

Scientific Instruments:

• 1. gamma-ray spectrometer
• 2. RMCh-1 meteorite detector
• 3. SL-1 radiometer for measuring radiation near the Moon
• 4. RFL-F instrument for detecting x-ray fluorescence
• 5. Kassiopeya KYa-4 instrument for measuring intensity of longwave radio-radiation
• 6. US-3 spectro-photometer
• 7. 2 cameras (high and low-resolution)
• 8. R-1 gear transmission experiment

Results: This subset of the "second generation" Luna spacecraft, the Ye-6LF, was designed to take the first photographs of the surface of the Moon from lunar orbit. A secondary objective was to obtain data on gravitational anomalies on the Moon (later identified by U.S. researchers as "mascons") also detected by Luna 10. Using the basic Ye-6 bus, a suite of scientific instruments included an imaging system similar to the one used on Zond 3, which was capable of high- and low-resolution imaging and whose lenses faced the direction of the S5.5 main engine. This package replaced the small lander capsule used on the soft-landing flights. The resolution of the photos was reportedly 15 to 20 meters. A technological experiment included testing the efficiency of gear transmission in vacuum for the future Ye-8 lunar rover (which worked successfully for 5 hours in vacuum). Luna 11, launched only two weeks after the U.S. Lunar Orbiter, successfully entered lunar orbit at 21:49 UT on 27 August about 5 minutes earlier than planned. Parameters were 163.5 × 1,193.6 kilometers. Within 3 hours of lunar orbit insertion, the spacecraft was to be stabilized for its imaging mission which would include taking 42 frames taken over a 64-minute session. Due to an off-nominal position of the vehicle, the camera only took images (64 of them) of blank space. Investigators determined that a foreign object had probably been dislodged in the nozzle of one of the attitude control thrusters. The other instruments functioned without fault (although no data was returned by the spectrophotometer) before the mission formally ended on 1 October 1966 after power supply had been depleted.