Beyond_Earth-_A_Chronicle_of_Deep_Space_Exploration_1958-2016.pdf

48

Mariner IV

Nation: USA (20)

Objective(s): Mars flyby

Spacecraft: Mariner-64D / Mariner-D

Spacecraft Mass: 260.8 kg

Mission Design and Management: NASA / JPL

Launch Vehicle: Atlas Agena D (Atlas Agena D no. 12 / Atlas D no. 288 / Agena D no. AD69/6932)

Launch Date and Time: 28 November 1964 / 14:22:01 UT

Launch Site: Cape Kennedy / Launch Complex 12

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Scientific Instruments:

• 1. imaging system
• 2. cosmic dust detector
• 3. cosmic ray telescope
• 4. ionization chamber
• 5. helium magnetometer
• 6. trapped radiation detector
• 7. solar plasma probe

On 15 July 1965, Mariner IV transmitted this image of the Martian surface from 12,600 kilometers away. The photograph shows a 150-kilometer diameter crater. Credit: NASA/JPL

Results: The Mariner IV mission, the second of two Mars flyby attempts in 1964 by NASA, was one of the great early successes of the Agency, and indeed the Space Age, returning the very first photos of another planet from deep space. Using a new all-metal shroud, the spacecraft lifted off without any problems and was successfully boosted towards Mars by the Agena D upper stage. A single midcourse correction on December 5 ensured that the spacecraft would fly between 8,000 and 9,660 kilometers from the Martian surface.

The Mariner IV spacecraft was assembled by engineers and technicians at the Jet Propulsion Laboratory in Pasadena, California. It is seen here being prepared for a weight test on 1 November 1963. Credit: NASA/JPL

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On one of the scientific instruments, the plasma probe, there was a component failure making its readings unintelligible although due to a better telemetry rate, some data was received between January and May 1965. Additionally, a Geiger tube, one of the two sensors in the ionization chamber experiment, failed and stopped returning data in March 1965. Approximately 40 minutes prior to closest approach (which was at 01:00:57 UT on 15 July 1965 at a range of 9,846 kilometers), the TV camera began taking the first of 21 images (plus 22 lines of a 22nd) through red and green filters. About 1.25 hours after the encounter, Mariner IV dipped behind the right-hand side of Mars (as viewed from Earth) in an occultation experiment in order to refract its radio signals through the Martian atmosphere. Data indicated that surface pressure was quite low, i.e., future Mars landers would have to be equipped with retro-rocket engines in addition to parachutes. The images as well as the occultation experiment fundamentally transformed the scientific view of the Red Planet, providing hard data where speculation had previously dominated. The probe detected daytime surface temperatures at about –100°C. A very weak radiation belt, about 0.1% of that of Earth's, was also detected. The day after the closest encounter, Mariner IV began transmitting its photos back to Earth. The images clearly showed Mars to be an ancient Moon-like body with widespread cratering, thus incontrovertibly quashing any expectations of lost civilizations on the planet. Given the thin atmosphere, scientists believed that it was unlikely that Mars harbored any life. NASA maintained contact with the spacecraft until 1 October 1965 when the probe was 309 million kilometers from Earth. Two years later, in October 1967, the spacecraft was reactivated for attitude control tests in support of the Mariner V mission to Venus that used a similar spacecraft bus. Contact was maintained until 31 December 1967, over three years after launch.

49

Zond 2

Nation: USSR (29)

Objective(s): Mars flyby

Spacecraft: 3MV-4A (no. 2)

Spacecraft Mass: 996 kg

Mission Design and Management: OKB-1

Launch Vehicle: Molniya + Blok L (8K78 no. G15000-29)

Launch Date and Time: 30 November 1964 / 13:25 UT

Launch Site: NIIP-5 / Site 1/5

Scientific Instruments:

• 1. radiation detector (STS-5 scintillation and gas-discharge counters)
• 2. charged particle detector
• 3. magnetometer
• 4. piezoelectric detector?
• 5. Kassiopeya radio telescope
• 6. TyaMV nuclear component of cosmic rays experiment
• 7. RSK-2M ultraviolet and Roentgen solar radiation experiment
• 8. imaging system

Results: This was the last of three "Object-Probe" test vehicles launched as part of the third generation ("3MV") Soviet interplanetary probes, and the first intended towards Mars. These were designed to test out key technologies during deep space missions. Originally intended to fly in the April-May 1964 time period, this launch was constantly delayed and then ultimately timed for the late 1964 Mars opportunity. Besides carrying out long-distance communications tests and imaging Earth on the way out into deep space, this vehicle's trajectory was designed to allow it to intercept Mars (on approximately 6 August 1965) and become the first probe to enter its atmosphere and impact on its surface. After successfully entering a trans-Mars trajectory, ground controllers discovered that the probe's solar panels had not completely unfurled, depriving the vehicle of full power. Later investigation indicated that a tug cord designed to pull the panels free at the moment of separation from the Block L upper stage had broken off. Controllers were able to fully open the panel only on 15 December 1964, after "carrying out a number of dynamic operations on the station" according to the official institutional history, but by then the time for the first mid-course correction to fly by Mars had already passed. (Other reports suggest that even after the panels opened, they were partially obscured by radiators installed at the end of the solar panels which had not properly deployed). Additionally, there had been a failure in the onboard programmed timer immediately after trans-interplanetary injection that led to inappropriate thermal conditions for the spacecraft between communications sessions. Before loss of contact, on 14 December, Zond 2 successfully fired six plasma electric rocket engines (twice) at a distance of 5.37 million kilometers from Earth. They were left "on" for 70 minutes and successfully maintained orientation of the spacecraft. These were technology demonstrators for future deep space missions. (These were actually carried on an earlier 3MV-1A model, launched on 11 November 1963, but that spacecraft failed to leave Earth orbit and was named Kosmos 21.) While some Western sources suggest that contact was maintained with Zond 2 until 4–5 May 1965, this is highly unlikely. The silent probe passed by Mars at a range of 650,000 kilometers on 6 August 1965 and entered heliocentric orbit. The spacecraft returned usable data on cosmic radio emissions at 210 and 2200 kc/second, up to 8 Earth radii distance from Earth.

All operations prior to landing occurred without fault. A 48-second mid-course correction at 19:29 UT on 1 February some 233,000 kilometers from the Moon directed the probe directly to its target in the Ocean of Storms. About one hour before touchdown at a distance of 8,300 kilometers, Luna 9 was put in proper attitude for retro-fire. Just prior to engine ignition, two side compartments were jettisoned, followed by inflation of two shock-absorbing airbags covering the lander to a pressure of 1 atmosphere. Its main S5.5A engine ignited at an altitude of 74.885 kilometers above the surface and fired for 48 seconds until the probe was just 260–265 meters above ground, thus decelerating Luna 9 from 2,600 meters/second to a few meters/second. Just above the surface, a long boom sensor made contact with the lunar surface, thus issuing a command to eject the 58-centimeter spheroid ALS capsule weighing 99.8 kilograms from the main bus. The ALS (still enclosed in surrounding airbags) landed a few meters away. The impact time was recorded as 18:45:30 UT on 3 February 1966 west of the Reiner and Marius craters in the Ocean of Storms (reported as 7° 8′ N / 64° 32′ W but closer to 8° N / 64° W). About four minutes after landing, the airbags split open, and the petals covering the top of the ALS were deployed. Precisely four minutes and 10 seconds after touchdown, Luna 9 began transmitting initial telemetry data back to Earth, although it would be another 7 hours (at 01:50 UT on 4 February, after the Sun climbed from 3° to 7° elevation) before the probe began sending back the first of nine images (including five panoramas) of the surface of the Moon. The first panoramic images arrived very early in the morning in Moscow, and because officials were afraid to wake up Soviet space program curator Dmitriy Ustinov (1908–1984) (whose permission was required for publication in the Soviet media), the first panoramic images were actually published in the British media courtesy of Sir Bernard Lovell (1913–2012) at the Jodrell Bank Observatory who had intercepted and analyzed the same data. The later images had the Sun much higher up, up to 41°, thus causing the shadow relief of the images to change. These were the first images sent back from the surface of another planetary body. Controllers noticed at one point that Luna 9's vantage point had slightly shifted over the sequence of images, possibly caused by the diminishing water supply of its thermal control system which changed its weight distribution. This change in perspective (of about 100 mm) opened up the possibility of stereo photography of the surface. The KS-17M radiation detector measured a dosage of 30 millirads per day. Perhaps the most important discovery from the mission was determining that a foreign object would not simply sink into the lunar dust, i.e., that the ground could support a heavy lander. Mission controllers expected that the last communications session would be on 5 February (from 16:00 to 17:41 UT) but were pleased to have an additional one, on 6 February (from 20:37 to 22:55 UT). By the time contact was lost, controllers had communicated with Luna 9 over seven communications sessions lasting 8 hours and 5 minutes.

66

Kosmos 111 [Luna]

Nation: USSR (41)

Objective(s): lunar orbit

Spacecraft: Ye-6S (no. 204)

Spacecraft Mass: c. 1,580 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Molniya-M + Blok L (8K78M no. N103-41, also U15000-50)

Launch Date and Time: 1 March 1966 / 11:03:49 UT

Launch Site: NIIP-5 / Site 31/6

Scientific Instruments:

• 1. magnetometer
• 2. gamma-ray spectrometer
• 3. five gas-discharge counters
• 4. two ion traps and a charged particle trap
• 5. piezoelectric micrometer detector
• 6. infrared detector
• 7. low-energy x-ray photon counters

Results: In early 1966, the Soviets hastily put together an interim lunar orbiter program, the Ye-6S, partly to upstage the American Lunar Orbiter project, and partly to commemorate the 23rd Congress of the Communist Party held in March 1966. Engineers quickly designed a set of two rudimentary probes using the old Ye-6 (lander) buses for these missions. The first of these was prepared in less than a month but failed to leave Earth orbit. During Earth orbit operations, the Blok L upper stage lost roll control and failed to fire to send the probe towards the Moon. The official Soviet media named the stranded satellite Kosmos 111 which reentered two days after launch.

67

Luna 10

Nation: USSR (42)

Objective(s): lunar orbit

Spacecraft: Ye-6S (no. 206)

Spacecraft Mass: 1,583.7 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Molniya-M + Blok L (8K78M no. N103-42, also U15000-51)

Launch Date and Time: 31 March 1966 / 10:46:59 UT

Launch Site: NIIP-5 / Site 31/6

Scientific Instruments:

• 1. SG-59M 3-component magnetometer
• 2. gamma-ray spectrometer
• 3. SL-1 radiometer for detecting radiation near the Moon
• 4. D-153 solar plasma detector
• 5. RMCh-1 meteorite detector
• 6. ID-1 infrared radiation detector
• 7. RFL-1 x-ray fluorescence detector

Results: After a mid-course correction on 1 April, Luna 10, the second and backup model of two hastily prepared Soviet Ye-6S probes, successfully entered lunar orbit two days later at 18:44 UT, thus becoming the first human-made object to go into orbit around another planetary body. A 248.5-kilogram instrument compartment separated from the main bus at 18:45:39 UT which was in a 350 × 1,016-kilometer orbit inclined at 71.9° to the lunar equator. The spacecraft carried a set of solid-state oscillators which had been programmed to reproduce the notes of the Internationale so that it could be broadcast live to the 23rd Communist Party Congress. During a rehearsal on the night of 3 April, the playback went well, but the following morning, controllers discovered a missing note and so played the previous night's tape to the assembled gathering at the Congress, claiming it was a live broadcast from the Moon. Luna 10 conducted extensive research in lunar orbit, gathering important data on the weakness of the Moon's magnetic field, radiation belts, and micrometeoroid density. In 2012, a Soviet scientist made the claim that Luna 10's achievements included "the first gamma-ray spectrometer used in the history of space research to first define the contents of natural radio nuclides in the lunar soil." Data from Luna 10 suggested that Moon rocks were comparable to terrestrial basalt rocks. Based on data collected by the probe, Efraim Akim (1929–2010) at the USSR Academy of Sciences identified the "noncentrality of the gravitational field of the Moon" which he argued was "the essential fact determining the evolution of the orbit of Luna 10," as reported in an Academy journal in 1966. Based on Akim's claim, some sources incorrectly credit Luna 10 with discovery of mass concentrations (called "mascons")—areas of high density below the mare basins that distort lunar orbital trajectories. Their discovery, however, came much later, after the creation of a gravimetric map of the Moon (albeit at the time, only of the near side of the Moon). Paul Muller and William Sjogren published their conclusions in 1968 based on data from the Lunar Orbiters showing that very large positive gravity anomalies exist in all of the circular ringed sea basins on the Moon. The discovery of mascons thus should be credited to them. Controllers made last contact with Luna 10 on 30 May 1966.