more at http://scitech.quickfound.net/astro/planet_news.html The flight of the Mariner 10 spacecraft to Venus and Mercury is detailed in animation and photography. Views of Mercury are featured. Included is animation on the origin of the solar system. Dr. Bruce C. Murray, director of the Jet Propulsion Laboratory, comments on the mission. Reupload of a previously uploaded film, in one piece instead of multiple parts, and with improved video and sound. NASA film HQ-282 from "The Voyage of Mariner 10: Mission to Venus and Mercury" http://history.nasa.gov/SP-424/sp424.htm The Mariner Venus/ Mercury 1973 spacecraft, which was the sixth of a series that began with Mariner Venus in 1962 and included Mariner Mars 1964, Mariner Venus 1967 Mariner Mars 1969 and Mariner Mars Orbiter 1971. In common with earlier spacecraft, it used an octagonal main structure, solar cells and a battery for electrical power, three-axis attitude stabilization and control by nitrogen gas jets, celestial references by star and Sun sensors, S-band radio for command, telemetry, and ranging, a high-gain antenna, a low-gain antenna, a scan platform to point science instruments, and a hydrazine rocket propulsion system for trajectory corrections. The spacecraft was designed to fit folded into the launch configuration of the Atlas SLV -3D/Centaur D-IA launch vehicle... Launch weight of the spacecraft was 533.6 kg (1175 Ib), including 29 kg (64 lb) of hydrazine propellant and 30 kg (66 1 b) associated with the adapter to the launch vehicle. The payload of scientific instruments weighed 78 kg (172 lb). Subsystems included equipment to modulate and demodulate electrical signals, generate, store, and distribute power, handle flight data, control spacecraft attitude, release mechanical devices, propel the spacecraft, control temperature, articulate and point spacecraft devices, store data onboard the spacecraft, and communicate with Earth. There was also a central computer and sequencer. All these subsystems together with mechanical devices used for deployment supported the science experiments. Some changes to the Mariner concept were needed for the mission to Mercury, principally because the spacecraft had to approach the Sun much closer than any previous planetary spacecraft. This required improved ways to insulate the spacecraft from solar radiation. Thermal control of the new Mariner had to protect it from solar intensities up to 4 1/2 times that incident upon the Earth. Thermal control required, in addition to a large sunshade, louvers and protective thermal blankets, the ability to rotate the solar panels about an axis that ran along their length. By changing the angle at which the sunlight shone on the panels, the solar cells were kept at a suitable temperature- about 115°C (239°F)- as the spacecraft approached closer to the Sun. Both panels could turn up to a total of 76 deg from directly facing the Sun and could be rotated individually in fine steps. Other major design changes from past Mariners included the addition of a capability to handle up to 118 thousand bits per second of TV data and 2450 bits/sec for nonimaging science and engineering data as well as the capability for both S- and X-band ranging and X-band carrier transmission. Also, a central flight data subsystem for science and engineering data processing and science control allowed engineering format to be programmed in flight and provided 21 data modes for television, nonimaging science, engineering, and data storage playback... The spacecraft had to be launched during a short, 1.5-hour "window" on November 2, 1973... Within 12 seconds of Atlas engine cutoff, the bright nucleus of the Centaur's twin engines blossomed in the night sky, to burn fiercely for 5.1 min to push the spacecraft into Earth parking orbit at an altitude of 188 km (117 mi) and a speed of 28,046 km/hr ( 17,428 mi/hr). Silently the Centaur and the spacecraft moved weightless nearly a third of the way around the Earth. Again the Centaur's engines erupted into flame, expanding exhaust jets into the vacuum of space. The Centaur and its payload bounded forward in orbit, breaking free of Earth's gravity within 2.25 min at a speed of 40,969 km/hr (25,458 mi/hr) headed backwards along Earth's orbit around the Sun... By February 4, Mariner 10 was 640,000 km (about 400,000 mi) from Venus and approaching the planet at a speed of over 29,600 km/hr ( 18,400 mi/hr)... At 9:21 a.m. PDT on February 5, 1974, Mariner started to take photographs... Mariner 10 began taking pictures of Mercury on March 23, from a distance of 5.3 million km (3 .3 million mi). Photography was intermittent for the next four days but became an almost continuous operation on March 28, one picture bemg taken every 42 sec...

• published: 14 Jul 2015
• views: 864