Beyond_Earth-_A_Chronicle_of_Deep_Space_Exploration_1958-2016.pdf

<!-- image -->

Pioneer 11

Nation: USA (53)

Objective(s): Jupiter flyby, Saturn flyby

Spacecraft: Pioneer-G

Spacecraft Mass: 258.5 kg

Mission Design and Management: NASA / ARC

Launch Vehicle: Atlas Centaur (AC-30 / Atlas 3D no. 5011D / Centaur D-1A)

Launch Date and Time: 6 April 1973 / 02:11 UT

Launch Site: Cape Kennedy / Launch Complex 36B

Scientific Instruments:

• 1. imaging photopolarimeter
• 2. helium vector magnetometer (HVM)
• 3. infrared radiometer
• 4. quadrispherical plasma analyzer
• 5. ultraviolet photometer
• 6. charged particle instrument (CPI)
• 7. cosmic ray telescope (CRT)
• 8. Geiger tube telescope (GTT)
• 9. Sisyphus asteroid/meteoroid detector (AMD)
• 10. meteoroid detectors
• 11. trapped radiation detector (TRD)
• 12. triaxial fluxgate magnetometer

Results: Pioneer 11, the sister spacecraft to Pioneer 10, was the first human-made object to fly past Saturn and also returned the first pictures of the polar regions of Jupiter. After boost by the TE-M-364-4 engine, the spacecraft sped away from Earth at a velocity of 51,800 kilometers/hour, thus equaling the speed of its predecessor, Pioneer 10. During the outbound journey, there were a number of malfunctions on the spacecraft—including the momentary failure of one of the RTG booms to deploy, a problem with an attitude control thruster, and the partial failure of the asteroidal dust detector—but none of these jeopardized the mission. Pioneer 11 passed through the asteroid belt without damage by mid-March 1974. Soon, on 26 April 1974, it performed a mid-course correction (after an earlier one on 11 April 1973) to guide it much closer to Jupiter than Pioneer 10 and ensure a polar flyby. Pioneer 11 penetrated the Jovian bow shock on 25 November 1974 at 03:39 UT. The spacecraft's closest approach to Jupiter occurred at 05:22 UT on 3 December 1974 at a range of 42,500 kilometers from the planet's cloud tops, three times closer than Pioneer 10. By this time, it was travelling faster than any human-made object at the time, 171,000 kilometers/hour. Because of its high speed during the encounter, the spacecraft's exposure to Jupiter's radiation belts spanned a shorter time than its predecessor although it was actually closer to the planet. Pioneer 11 repeatedly crossed Jupiter's bow shock, indicating that the Jovian magnetosphere changes its boundaries as it is buffeted by the solar wind. Besides the many images of the planet (and better pictures of the Great Red Spot), Pioneer 11 took about 200 images of the moons of Jupiter. The vehicle then used Jupiter's massive gravitational field to swing back across the solar system to set it on a course to Saturn. After its Jupiter encounter, on 16 April 1975, the micrometeoroid detector was turned off since it was issuing spurious commands which were interfering with other instruments. Mid-course corrections on 26 May 1976 and 13 July 1978 sharpened its trajectory towards Saturn. Pioneer 11 detected Saturn's bow shock on 31 August 1979, about a million-and-a-half kilometers out from the planet, thus providing the first conclusive evidence of the existence of Saturn's magnetic field. The spacecraft crossed the planet's ring plane beyond the outer ring at 14:36 UT on 1 September 1979 and then passed by the planet at 16:31 UT for a close encounter at 20,900-kilometer range. It was moving at a relative velocity of 114,100 kilometers/hour at the point of closest approach. During the encounter, the spacecraft took 440 images of the planetary system, with about 20 at a resolution of 90 kilometers. Those of Saturn's moon Titan (at a resolution of 180 kilometers) showed a featureless orange fuzzy satellite. A brief burst of data on Titan indicated that the average global temperature of Titan was –193°C. Among Pioneer 11's many discoveries were a narrow ring outside the A ring named the "F" ring and a new satellite 200 kilometers in diameter. The spacecraft recorded the planet's overall temperature at –180°C and photographs indicated a more featureless atmosphere than that of Jupiter. Analysis of data suggested that the planet was primarily made of liquid hydrogen. After leaving Saturn, Pioneer 11 headed out of the solar system in a direction opposite to that of Pioneer 10, i.e., to the center of galaxy in the general direction of Sagittarius. Pioneer 11 crossed the orbit of Neptune on 23 February 1990 becoming the fourth spacecraft (after Pioneer 10, Voyager 1 and 2) to do so. Scientists expected that during their outbound journeys, both Pioneer 10 and 11 would find the boundary of the heliosphere where the solar wind slows down and forms a "termination shock," beyond which there would be the heliopause and finally the bow shock of the interstellar medium, i.e., space beyond the solar system. By 1995, 22 years after launch, two instruments were still operational on the vehicle. NASA Ames Research Center made last contact with the spacecraft on 30 September 1995 when Pioneer 11 was 44.1 AU from Earth. Scientists later received a few minutes of good engineering data on 24 November 1995 but lost contact again once Earth moved out of view of the spacecraft's antenna. Like Pioneer 10, Pioneer 11 also carries a plaque with a message for any intelligent beings. By 5 November 2017, it was estimated to be about 97.590 AU (or 14.599 billion kilometers) from Earth.

Completed in 1973, Deep Space Station 63 (DSS-63) was the third 64-meter antenna of NASA's Deep Space Network. Located in Robledo de Chevala near Madrid, DSS-63 received its first signals from Pioneer 10 and Mariner 10. Credit: NASA

<!-- image -->

Explorer 49

Nation: USA (54)

Objective(s): lunar orbit

Spacecraft: RAE-B

Spacecraft Mass: 330.2 kg

Mission Design and Management: NASA / GSFC

Launch Vehicle: Delta 1913 (DSV-3P-11 no. 95 or “Delta-95” / Thor no. 581)

Launch Date and Time: 10 June 1973 / 14:13:00 UT

Launch Site: Cape Canaveral / Launch Complex 17B

Scientific Instruments:

• 1. galactic studies experiment
• 2. sporadic low-frequency solar radio bursts experiment
• 3. sporadic Jovian bursts experiment
• 4. radio emission from terrestrial magnetosphere experiment
• 5. cosmic source observation experiment

Results: Explorer 49 was the final U.S. lunar mission for 21 years (until Clementine in 1994). The spacecraft, part of a duo of Radio Astronomy Explorer (RAE) missions (other being Explorer 48), was designed to conduct comprehensive studies of low frequency radio emissions from the Sun, Moon, the planets, and other galactic and extra-galactic sources, while in a circular orbit around the Moon. Its location was driven by the need to avoid terrestrial radio interference. After launch on a direct ascent trajectory to the Moon and one mid-course correction on 11 June, Explorer 49 fired its insertion motor on 07:21 UT on 15 June to enter orbit around the Moon. Initial orbital parameters were 1,334 × 1,123 kilometers at 61.3° inclination. On 18 June the spacecraft jettisoned its main engine and, using its Velocity Control Propulsion System, circularized its orbit to 1,063 × 1,052 kilometers at 38.7° inclination. The spacecraft was the largest human-made object to orbit the Moon with its deployed antennas measuring 457.2 meters (nearly half a kilometer!) tip-to-tip. These antennas, as well as a 192-meter long damper boom and a 36.6-meter dipole antenna were all stored away on motor-driven reels which allowed them to unfurl in lunar orbit. Once in lunar orbit, the spacecraft deployed its various antennae in stages, assuming its full form by November 1974. During its mission, Explorer 49 studied low-frequency radio emissions from the solar system (including the Sun and Jupiter) and other galactic and extra-galactic sources. NASA announced completion of the mission in June 1975 although contact was maintained until August 1977.

Artist's impression of fully deployed Explorer 49 in orbit around the Moon. Credit: NASA

<!-- image -->

Mars 4

Nation: USSR (86)

Objective(s): Mars orbit

Spacecraft: M-73S (3MS no. 52S)

Spacecraft Mass: 4,000 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: Proton-K + Blok D (8K82K no. 261-01 + 11S824 1701L)

One of 12 images taken by the Vega imaging system on board the Soviet Mars 4 spacecraft. The vehicle failed to enter orbit around Mars but took these photos during its flyby on 10 February 1974. Credit: Don Mitchell

<!-- image -->

Launch Date and Time: 21 July 1973 / 19:30:59 UT

Launch Site: NIIP-5 / Site 81/23

Scientific Instruments:

• 1. atmospheric radio-probing instrument
• 2. radiotelescope
• 3. infrared radiometer
• 4. spectrophotometer
• 5. narrow-band photometer
• 6. narrow-band interference-polarization photometer
• 7. imaging system (OMS scanner + 2 TV cameras)
• 8. photometers
• 9. two polarimeters
• 10. ultraviolet photometer
• 11. scattered solar radiation photometer
• 12. gamma spectrometer
• 13. magnetometer
• 14. plasma traps
• 15. multi-channel electrostatic analyzer

Results: Mars 4 was one of four Soviet spacecraft of the 3MS (or M-73) series launched in 1973. Soviet planners were eager to preempt the American Viking missions planned for 1976 but were limited by the less advantageous positions of the planets which allowed the Proton-K/Blok D boosters to launch only limited payloads towards Mars. The Soviets thus separated the standard pair of orbiter-lander payload combinations into two orbiters and two landers. Less than four months prior to launch, ground testing detected a major problem with the 2T312 transistors (developed by the Pulsar Scientific-Research Institute) used on all four vehicles, apparently because the factory that manufactured it used aluminum contacts instead of gold-plated contacts. An analysis showed that the transistors' failure rate began to increase after 1.5 to 2 years operation, i.e., just about when the spacecraft would reach Mars. Despite the roughly 50% odds of success, the government decided to proceed with the missions. The first spacecraft, Mars 4, successfully left Earth orbit and headed towards Mars and accomplished a single mid-course correction on 30 July 1973, but soon two of three channels of the onboard computer failed due to the faulty transistors. As a result, the second mid-course correction by its main 11D425A engine could not be implemented. With no possibility for Mars orbit insertion, Mars 4 flew by the Red Planet at 15:34 UT on 10 February 1974 at a range of 1,844 kilometers. Ground control was able to command the vehicle to turn on its TV imaging system (Vega-3MSA) 2 minutes prior to this point (at 15:32:41) to begin a short photography session of the Martian surface during the flyby. (The other TV camera system known as Zufar-2SA was never turned on due to a failure). The TV camera took 12 standard images from ranges of 1,900 to 2,100 kilometers distance over a period of 6 minutes. The other OMS scanner also provided two panoramas of the surface. The spacecraft eventually entered heliocentric orbit.

Mars 5

Nation: USSR (87)

Objective(s): Mars orbit

Spacecraft: M-73S (3MS no. 53S)

Spacecraft Mass: 4,000 kg

Mission Design and Management: GSMZ imeni Lavochkina

Launch Vehicle: 8K82K + Blok D (Proton-K no. 262-01 + 11S824 no. 1801L)

Launch Date and Time: 25 July 1973 / 18:55:48 UT

Launch Site: NIIP-5 / Site 81/24

Scientific Instruments:

• 1. atmospheric radio-probing instrument
• 2. radiotelescope
• 3. infrared radiometer
• 4. spectrophotometer
• 5. narrow-band photometer
• 6. narrow-band interference-polarization photometer
• 7. imaging system (OMS scanner + 2 TV cameras)
• 8. photometers
• 9. VPM-73 polarimeter unit
• 10. ultraviolet photometer
• 11. scattered solar radiation photometer
• 12. gamma spectrometer
• 13. magnetometer
• 14. plasma traps
• 15. multi-channel electrostatic analyzer

Results: Mars 5 was the sister Mars orbiter to Mars 4. After two mid-course corrections on 3 August 1973 and 2 February 1974, Mars 5 successfully fired its main engine at 15:44:25 UT to enter orbit around the planet. Initial orbital parameters were 1,760 × 32,586 kilometers at 35° 19′ 17″ inclination. Soon after orbital insertion, ground controllers detected the slow depressurization of the main instrument compartment on the orbiter, probably as a result of an impact with a particle during or after orbital insertion. Calculations showed that at the current rate of air loss, the spacecraft would be operational for approximately three more weeks. Scientists drew up a special accelerated science program that included imaging of the surface at 100-meter resolution. Five imaging sessions on 17, 21, 23, 25 and 26 February 1974 produced a total of 108 frames comprising only 43 usable photographs. Both the high-resolution Vega-3MSA and the survey Zufar-2SA TV cameras were used. Additionally, Mars 5 used the OMS scanner to take five panoramas of the surface. The last communication with Mars 5, when the final panorama was transmitted back to Earth, took place on 28 February 1974, after which pressure in the spacecraft reduced below working levels. Mars 5's photos, some of which were of comparable quality to those of Mariner 9, clearly showed surface features which indicated erosion caused by free-flowing water. The first of these images taken by both the television cameras were published in the Academy of Sciences' journal in the fall of 1974. Among significant achievements claimed for Mars 5 was "receipt of mean data on the chemical composition of rocks on Mars for the first time." The vehicle was supposed to act as a data relay for the Mars 6 and Mars 7 landers which arrived in March 1974 but was obviously unable to do so.