Date: Wed, 2 Sep 92 05:02:19 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #156 To: Space Digest Readers Precedence: bulk Space Digest Wed, 2 Sep 92 Volume 15 : Issue 156 Today's Topics: Electronic Journal of the ASA (EJASA) - September 1992 Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: Tue, 1 Sep 1992 18:18:59 GMT From: Larry Klaes Subject: Electronic Journal of the ASA (EJASA) - September 1992 Newsgroups: sci.astro,sci.space,sci.geo.geology,sci.misc THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC Volume 4, Number 2 - September 1992 ########################### TABLE OF CONTENTS ########################### * ASA Membership and Article Submission Information * The Great Moon Race: The Long Road to Success - Andrew J. LePage ########################### ASA MEMBERSHIP INFORMATION The Electronic Journal of the Astronomical Society of the Atlantic (EJASA) is published monthly by the Astronomical Society of the Atlantic, Incorporated. The ASA is a non-profit organization dedicated to the advancement of amateur and professional astronomy and space exploration, as well as the social and educational needs of its members. ASA membership application is open to all with an interest in astronomy and space exploration. Members receive the Journal of the ASA (hardcopy sent through United States Mail - Not a duplicate of this Electronic Journal) and the Astronomical League's REFLECTOR magazine. Members may also purchase discount subscriptions to ASTRONOMY and SKY & TELESCOPE magazines. For information on membership, you may contact the Society at any of the following addresses: Astronomical Society of the Atlantic (ASA) c/o Center for High Angular Resolution Astronomy (CHARA) Georgia State University (GSU) Atlanta, Georgia 30303 U.S.A. asa@chara.gsu.edu ASA BBS: (404) 564-9623, 300/1200/2400 Baud. or telephone the Society Recording at (404) 264-0451 to leave your address and/or receive the latest Society news. ASA Officers and Council - President - Don Barry Vice President - Nils Turner Secretary - Ingrid Siegert-Tanghe Treasurer - Mike Burkhead Directors - Bill Bagnuolo, Eric Greene, Tano Scigliano Council - Bill Bagnuolo, Bill Black, Mike Burkhead, Frank Guyton, Larry Klaes, Ken Poshedly, Jim Rouse, Tano Scigliano, John Stauter, Wess Stuckey, Harry Taylor, Gary Thompson, Cindy Weaver, Bob Vickers ARTICLE SUBMISSIONS - Article submissions to the EJASA on astronomy and space exploration are most welcome. Please send your on-line articles in ASCII format to Larry Klaes, EJASA Editor, at the following net addresses or the above Society addresses: klaes@verga.enet.dec.com or - ...!decwrl!verga.enet.dec.com!klaes or - klaes%verga.dec@decwrl.enet.dec.com or - klaes%verga.enet.dec.com@uunet.uu.net You may also use the above addresses for EJASA back issue requests, letters to the editor, and ASA membership information. When sending your article submissions, please be certain to include either a network or regular mail address where you can be reached, a telephone number, and a brief biographical sketch. Back issues of the EJASA are also available from anonymous FTP at chara.gsu.edu DISCLAIMER - Submissions are welcome for consideration. Articles submitted, unless otherwise stated, become the property of the Astronomical Society of the Atlantic, Incorporated. Though the articles will not be used for profit, they are subject to editing, abridgment, and other changes. Copying or reprinting of the EJASA, in part or in whole, is encouraged, provided clear attribution is made to the Astronomical Society of the Atlantic, the Electronic Journal, and the author(s). Opinions expressed in the EJASA are those of the authors' and not necessarily those of the ASA. This Journal is Copyright (c) 1992 by the Astronomical Society of the Atlantic, Incorporated. THE GREAT MOON RACE: THE LONG ROAD TO SUCCESS Copyright (c) 1992 by Andrew J. LePage The author gives permission to any group or individual wishing to distribute this article, so long as proper credit is given and the article is reproduced in its entirety. As 1962 was drawing to a close, the situation with the American Moon program looked bleak. The failure of RANGER 5 was NASA's sixth consecutive lunar mission failure in three years. Only seventeen months after President John F. Kennedy committed the United States to landing a man on Earth's Moon with Project APOLLO, it was beginning to look as though the Americans would never make it. If they could not get a simple unmanned probe to the Moon in working order, how could they hope to pull off the much more complicated mission of a manned lunar landing? Investigations into the failure of the RANGER program started on October 30, 1962. Over the course of the next month, several groups inside NASA and out examined every aspect of the RANGER project in an attempt to pin down the causes of the failures and recommend changes. On November 30, NASA Headquarters released the findings of its inquiry: In brief, the report recommended streamlining management and changing the mission goals to be more in line with the needs of APOLLO. This meant concentrating on lunar imaging and dropping all other experiments on the Block III RANGER. The report also called for a thorough re-evaluation of the RANGER design, modifying vulnerable systems and the inclusion of more backup systems. The Jet Propulsion Laboratory (JPL) would be required to use outside contractors to build the three advanced Block IV RANGERs then being contemplated, instead of in-house as was the case with the first three Blocks. More extensive testing of systems and better quality control for components were recommended. Most of all, the report called for the immediate abandonment of sterilization. Sterilization was pinpointed as the cause of many of RANGER's system failures and it was now felt to be unnecessary, given that the hostile lunar environment was unlikely to harbor any indigenous life forms. Unless these changes were made, the Block III RANGERs were likely to suffer the same fate as its predecessors. With these recom- mendations in hand, JPL set about redesigning and rebuilding the Block III RANGERs. The scheduled launch of what would be RANGER 6 was delayed until late 1963. A Change in Plans As a result of fears that JPL's problems with RANGER could recur in its SURVEYOR program, and because of the continuing development problems with the ATLAS-CENTAUR rocket, NASA Headquarters began to examine possible alternatives to SURVEYOR. Langley Research Center was quietly directed by Headquarters in 1962 to examine the possibility of using a lightweight lunar orbiter launched by the improved ATLAS-AGENA D to perform a photographic mapping mission in place of the heavier SURVEYOR B orbiter. Any more major delays in either the SURVEYOR or ATLAS-CENTAUR programs could severely impact the schedule of the all-important APOLLO program. High resolution photographs of potential landing sites were urgently needed. The studies conducted indicated that it was feasible to build a small lunar orbiter that would provide the needed lunar photographs. By March of 1963, the basic design for LUNAR ORBITER was completed and the project approved. On August 30, the newly created LUNAR ORBITER Project Office at Langley issued a request for proposals for its new lunar project. The goal was to build an orbiter that could image potential APOLLO landing sites five degrees north and south of the equator between 45 degrees east and west longitude with a resolution of one meter (3.3 feet). The first flight was expected in 1966. NASA had similar concerns about the lander portion of the SURVEYOR program. In 1963, JPL began studies on an ATLAS-AGENA D launched Block V RANGER that would carry a small soft lander built by Northrop. This option, as it turned out, was never exercised and was dropped along with the advanced Block IV RANGER by the end of 1963, partially for budgetary reasons. With its orbiter mission deleted, JPL's SURVEYOR program continued by concentrating on building a lunar lander. The program's goals were now altered to directly support APOLLO. SURVEYOR would be used as an engineering tool to develop the techniques needed to land on the Moon. At the end of 1963, a total of seven flights were planned. The first four would be test flights, while the last three would be operational. The first SURVEYOR flight was still optimistically targeted for late 1964. Options for additional flights of heavier and more advanced SURVEYOR landers that would incorporate more of the originally planned experiments and possibly a small rover were still being considered. For this it would be required that the usable payload of the launch vehicle could be increased sufficiently. Progress with SURVEYOR's launch vehicle, the ATLAS-CENTAUR, continued at a steady pace during 1963. The second test launch, ATLAS-CENTAUR 2, finally occurred during the afternoon of November 11 after months of delays. The goal of this flight was to simply get into orbit. No second burn of the CENTAUR's advanced, hydrogen burning RL-10 engines was being considered on this flight. The five-ton (4.5 metric ton) CENTAUR was successfully placed into a lofty 303 by 1,093- mile (488 by 1,759-kilometer) orbit without any major problems. Much work remained to be done to perfect this fickle machine, but at last there seemed to be a light at the end of the tunnel. The New and Improved RANGER The improved Block III RANGER was finally ready by the end of 1963. Much had been changed from the previous design. The RANGER hexagon-shaped bus was similar to previous models with some notable exceptions. First, the bus' framework was now made of aluminum due to its better thermal characteristics. A second battery to provide additional backup power was added. The course correction system was enlarged to provide a 135-mile per hour (60-meter per second) velocity change capability; a one-third increase over the Block II RANGER. The sequencer was redesigned to incorporate components which were not heat sterilized. This included features that increased the chances of a successful mission in case of equipment failure. A second, independent attitude control jet system was added for redundancy. The bus was also fitted with new rectangular-shaped solar panels similar to the ones carried by the MARINER 2 Venus probe in 1962. This design had portions of the panels electrically isolated from each other to avoid a repeat of the total solar panel failure experienced by RANGER 5. All of these changes increased the weight of the Block III RANGER. This prompted the deletion of every instrument except for the television camera package to keep the probe under 810 pounds (368 kilograms). Two independent chains of RCA-developed slow scan vidicon cameras were enclosed in a five-foot (1.5-meter) tall tower mounted on top of the bus. Clad in polished aluminum for thermal control, the 380-pound (173-kilogram) cylindrical tower tapered from 27 inches (69 centimeters) at its base to 16 inches (41 centimeters) at the top, where the low- gain antenna was mounted. The six cameras viewed the approaching lunar surface through a 13-inch (33-centimeter) square opening on the side of the tower. Their optical axes were canted at a 28-degree angle from the spacecraft's long axis. Also enclosed inside the tower were two independent power supplies, camera sequencers, and batteries; one set for each chain of cameras. Each chain also possessed its own sixty-watt transmitter to independently transmit images in real time back to Earth. The bus still carried its own three-watt transmitter which would now only carry engineering telemetry. The first camera chain was the full scan or F chain, which consisted of two cameras. One camera was fitted with a 35-millimeter lens, providing a 25-degree field of view, while the other used a 76-millimeter lens with an 8.4-degree field of view. Each camera would scan the entire 1,152-line vidicon once the exposure had been taken. As a set, the F chain returned one image every 2.56 seconds. Normally the camera would be turned on by commands sent from Earth. If this failed, the bus' onboard sequencer would activate the package at a preset time. If this failed, the F chain had its own timer that was activated by the spacecraft's separation from the AGENA B escape stage. After 67 hours and 45 minutes of flight, the F chain would automatically turn on and start transmitting images. In this way, even if both primary systems were to fail, at least a few hundred full scan images would be returned. Independent of the F chain was a second set of four partial scan vidicon cameras called the P chain. Like the F chain, 35 and 76-millimeter lenses were used, but only three hundred partial lines - about seven percent of the vidicon's face - was read and transmitted back to Earth. This resulted in images with the same resolution as the F chain but covering a smaller area. This was done so that images could be returned at a rate of five images per second in hopes of capturing at least a partial image a couple of tenths of a second before impact. At this altitude of only one or two thousand feet (300 to 600 meters), a resolution of one foot (0.3 meters) or better was possible. If the F chain were to malfunction, the P chain could independently return thousands of images after receiving a command either directly from Earth or from RANGER's central sequencer and timer. With all these hardware changes, including redundant and more fault tolerant systems as well as five hundred to eight hundred hours of prelaunch testing, the new Block III RANGER was much more likely to reach its target in working order. The Block III mission profile was very similar to the Block II up until the encounter with the Moon. Since the Block III probe did not have to be concerned with the site and trajectory requirements of a lander, the impact point could be over a much larger range of longitude near the lunar equator. Typically the most easterly aim point was targeted at the beginning of the launch window. The aim point then drifted westward by about thirteen degrees of longitude per day, so that the impact point would have the optimum lighting conditions. About one hour before impact, the spacecraft would begin its terminal maneuver and reorient itself. This aims the cameras along RANGER's flight path towards approaching lunar surface and the high gain antenna is again pointed towards Earth. Some seventeen minutes before impact, the F chain of cameras is commanded to warm up for ninety seconds. The P chain then takes its turn and warms up. Finally, fourteen minutes before impact at an altitude of about 1,200 miles (1,900 kilometers), the F chain's sixty-watt transmitter starts beaming images back to Earth, followed by the P chain typically 2.5 minutes later. Transmission would continue until the spacecraft impacted the lunar surface at 5,800 miles per hour (2,600 meters per second). If everything worked perfectly, over 4,200 close up television images of the lunar surface would be transmitted. More Failure Because of various minor schedule slips, the first modified Block III spacecraft, RANGER A, was ready for launch by the beginning of 1964. Its primary targets were in the smooth equatorial mare regions, which were considered likely APOLLO landing sites. On the first day of the launch window, the site would be a point at 8.5 degrees north and 21.0 degrees east in Mare Tranquillitatis, the Sea of Tranquility. After several short holds, RANGER 6 lifted off on its first attempt on January 30. The launch and injection into a translunar trajectory went perfectly except for a telemetry channel that switched into an unscheduled mode for 67 seconds when the booster engines separated from the ATLAS. Initial tracking of RANGER 6 indicated that it would miss the Moon by about 600 miles (965 kilometers). More refined calculations later indicated a miss of only 495 miles (796 kilometers) that was corrected by a one minute, seven second burn of the course correction motor about sixteen hours and 41 minutes after launch. This 92.2-mile per hour (41.2-meter per second) change of velocity placed RANGER 6 on course for an impact on the western edge of Mare Tranquillitatis 40 miles (65 kilometers) south of the crater called Ross. On February 2, as RANGER 6 passed the 1,290-mile (2,076-kilometer) altitude mark moving at 4,471 miles per hour (1,998 meters per second), the television cameras were switched into warm up mode with all systems functioning normally. When the time came for the cameras to switch to full power and start returning images, however, only static was received. Quickly a series of emergency commands were sent from Earth, but to no avail. RANGER 6 crashed into the lunar surface at 9.39 degrees north, 21.51 degrees east at a speed of 5,946 miles per hour (2,658 meters per second) without returning a single picture. RANGER 6 was definitely a very successful engineering test. With the exception of the cameras, all systems worked perfectly. In addition, the navigation accuracy was the best ever attained; the spacecraft impacted the Moon only 19 miles (31 kilometers) from its aim point and only 0.3 seconds before its post-mid-course maneuver predicted impact time. Still, from the science community's and public's point of view, this was NASA's seventh consecutive lunar mission failure. NASA Headquarters formed another board of inquiry to investigate this mishap. The March launch of RANGER B was postponed pending the outcome of this new investigation. The pressure was on NASA and JPL was fighting for its life. After a self-imposed hiatus, the Soviets began anew their attempts to reach the Moon. In contrast to their early successes, this new generation of LUNA spacecraft suffered even more failures. According to Western intelligence sources, the Soviets first lunar mission since LUNA 4 failed to reach Earth parking orbit due to a launch vehicle malfunction sometime around February or March of 1964. Yet another LUNA was lost around April 20 due to another MOLNIYA launch failure. Possibly as a result of these new failures, the Soviets postponed additional LUNA launch attempts for almost another year while the bugs were worked out of the MOLNIYA. The NASA investigation into the failure of the RANGER 6 camera package was released on March 17. The 75-page report pinned the problem squarely on the RCA camera package itself. The completely redundant camera system was found not to be perfectly so. There was a single line that carried commands to both camera chains. Somehow a command was sent to the camera package during ascent that turned it on, hence the anomalous telemetry reading during launch. The cameras were turned on and, in the relatively dense atmosphere, both camera power supplies arced and shorted out. While the source of the errant command was not known at the time, several changes in the RCA camera package were suggested. These included changes to simplify ground testing and in-flight operation, telemetry system modifications to increase failure mode coverage, inclusion of additional noise suppression in the camera command circuitry, and a more rigorous prelaunch inspection of the television circuitry. These changes also included an interlock that would prevent the cameras from being turned on during launch. In addition, the tower temperature would be lowered by twenty degrees Fahrenheit (eleven degrees Celsius). While these changes would further increase RANGER's chances of success, the blame did not totally lie with RANGER. It was later discovered that the jettisoning of the ATLAS booster engines caused RANGER's cameras to turn on. When the ATLAS dropped its booster engines, about 400 pounds (180 kilograms) of propellant were expelled and ignited by the sustainer. This small detonation had caused some problems during the development of the ATLAS E/F ICBM but was never a problem for the ATLAS D. The detonation wave produced during the flight of RANGER 6 worked its way into a mechanically sealed umbilical door on the AGENA. The umbilical pin that controlled the camera package was 0.25 inches (6 millimeters) from another pin carrying twenty volts. The burning fuel vapor was conductive enough to short the two pins briefly, cause the camera package to turn on prematurely and, as a result, burn out. Success! By the summer of 1964, RANGER B had been modified and was ready to be launched during the next launch window in late July. There were some who wanted to target RANGER B close to the impact point of RANGER 6 to observe the crater it produced. Unfortunately the trajectory constraints of this launch window would not allow an impact that far east. Instead, several targets were considered for the first day of the launch period on July 27 along seven degrees west longitude between 21 degrees north and 14 degrees south latitude. The launch on this first day was scrubbed due to problems with the ground-based portion of the guidance system. Finally, on July 28, RANGER 7 successfully lifted off only 7.9 seconds into its launch window aimed at 11 degrees south, 21 degrees west in the northwest portion of Mare Nubium. With a good injection burn from the AGENA B, it was calculated that RANGER 7 would skim over the leading edge of the Moon and impact on its far side. A fifty-second course correction burn the day after launch brought the predicted impact point within the intended target area. When RANGER 7 was 1,415 miles (2,277 kilometers) above the lunar surface traveling at 4,290 miles per hour (1,917 meters per second), the F chain cameras were placed into the ninety-second warmup mode followed later by the P chain. Much to the relief of JPL and NASA officials, pictures from the F chain cameras started streaming back to Earth seventeen minutes and thirteen seconds before impact, followed three minutes and 33 seconds later by the P chain. By the time RANGER 7 plowed into the lunar surface 68 hours, 35 minutes, and 42 seconds after launch, 4,316 pictures pictures had been transmitted back to Earth. The last image, only a portion of which was transmitted before destruction, was made at an altitude of only one thousand feet (three hundred meters), showing features as small as three feet (one meter) across. RANGER 7 had impacted at 10.7 degrees south, 20.7 degrees west, only eight miles (thirteen kilometers) from its aim point. It was the first major American lunar mission success after almost six years of attempts. The pictures returned by RANGER 7 confirmed that the lunar mare regions are quite smooth and apparently free of major hazards for the APOLLO Lunar Module. Because of the size and shape of the craters and the topography observed during the approach, it seemed unlikely that the lunar surface was coated with a deep dust layer that could bury a lunar lander upon touchdown, as some had feared. With a solid success under their belts, worked continued on RANGER's followup programs, LUNAR ORBITER and SURVEYOR. On May 10, 1964, Boeing was awarded the contract for the LUNAR ORBITER, beating out a Lockheed bid which had proposed a spacecraft based on its military reconnaissance satellite. The 830-pound (380-kilogram) lunar satellite was planned to be placed into a 575-mile (925-kilometer) high circular orbit for its initial survey of potential APOLLO landing sites. Later the orbit would be adjusted so that LUNAR ORBITER could swoop within 28 miles (45 kilometers) of selected target areas for more detailed inspections. The imaging system that was planned would record images on photographic film, which would be developed automatically onboard, a technique first used by the Soviet Union with the flight of LUNA 3 in 1959. The photographs would then be scanned and transmitted back to Earth over the course of ten days. A total of five flights were planned starting in middle 1966 and continuing at quarterly intervals afterwards. Substantial advances also continued to be made with the SURVEYOR program. Extensive testing of a prototype had been completed and testing of various systems was proceeding more or less on schedule. The weight estimate for the operational spacecraft was settling around 2,150 pounds (975 kilograms) of which 65 pounds (30 kilograms) would be instrumentation. On the three operational flights, an approach and two surface television cameras would be carried along with an alpha scattering instrument to measure soil composition, a seismograph, micrometeoroid detectors, and a soil dynamics experiment. Minimal instrumentation would be carried on the first four test flights now expected sometime in 1966. Studies on the SURVEYOR follow on mission, known as Block II, were completed by late 1964. One of the payloads still under consideration for this 2,600 pound (1,200 kilogram) lander was a 150-pound (70- kilogram) rover that could make soil bearing and topographic studies up to two miles (three kilometers) from the lander. In order to lift this much heavier payload, studies indicated that the CENTAUR stage would have to be upgraded and modified to make use of a liquid oxygen/liquid fluorine mixture known as FLOX to replace the normally used liquid oxygen (LOX) oxidizer. The inclusion of highly reactive liquid fluorine in the oxidizer was expected to greatly increase the performance of the CENTAUR. Assuming the program was funded and the FLOXed CENTAUR was available, the first of as many as ten Block II SURVEYOR flights would take place around 1968. The ATLAS-CENTAUR test program was having mixed results. ATLAS- CENTAUR 3, launched on June 30, 1964, failed to reach Earth orbit, although some tests were conducted with the CENTAUR. ATLAS-CENTAUR 4 was launched on December 11 into a 101 by 107-mile (163 by 172-kilometer) parking orbit carrying a dynamic mass model of SURVEYOR in a flight to test the integrity of the total system. A secondary objective was to test the new upper stage's restart capability for the first time. While the primary objectives were met, the CENTAUR failed to reignite and propel itself into a simulated lunar trajectory. The now inert stage fell out of orbit the following day. Because of the continued problems with the ATLAS-CENTAUR, the goals of the development program were changed to provide a direct ascent capability for SURVEYOR in 1966. While such a trajectory is less than optimum, it did have the advantage of requiring the CENTAUR to fire only once, thus avoiding the problems encountered developing an in-flight restart capability. The initial flights of SURVEYOR would be light enough and the ATLAS-CENTAUR accurate enough to make such a flight possible. A parking orbit capability would be available later in the year and an increased lift capability would be available in 1967. The Assault Begins The year 1965 would witness the most intense wave of lunar probes since the beginning of the Space Age. The first mission of the year started on February 17 with the successful launch of RANGER 8. Like its predecessors, it was targeted for the most promising class of APOLLO landing sites, the smooth equatorial mare regions. For this mission, the selected aim point was 3 degrees north, 24 degrees east in Mare Tranquillitatis about 130 miles (210 kilometers) south of the impact point of RANGER 6. After injection into a translunar trajectory, tracking indicated that RANGER 8 would miss the Moon by 1,136 miles (1,828 kilometers). This was negated by a 59-second mid-course correction burn at a distance of 99,281 miles (159,743 kilometers). During the burn, however, controllers were alarmed by a loss of telemetry from the receding spacecraft. Concerned about attempting any more maneuvers, it was decided that RANGER 8 would not perform the terminal descent maneuver to align RANGER's cameras with its flight path. While this would smear the last few images returned by the quickly descending probe, it did offer the opportunity to take a swath of images over a wider area that would partially overlap with the early images returned by RANGER 7. Stereo images would also be procured in the process. As the probe approached the Moon, the cameras were turned on 23 minutes before impact, almost ten minutes before normally planned. The resolution of these first images was comparable with the best Earth-based telescopic photographs. As RANGER 8 screamed towards its destruction, the robot craft continued returning a stream of pictures which were very similar to those returned by the previous probe. The maria all seemed to have similar topography and presented no major problems for a landing, manned or otherwise. RANGER 8 then crashed into the Moon, producing a 45-foot (14-meter) diameter crater at 2.59 degrees north, 24.77 degrees east, only 14 miles (23 kilometers) southeast from its aim point. RANGER 8 returned a total of 7,137 pictures, the best of which showed features as small as five feet (1.5 meters) across. The American lunar program finally seemed to be on the road to success. On March 12, only three weeks after RANGER 8 impacted Earth's natural satellite, the Soviet Union launched another lunar lander. Unfortunately the MOLNIYA's escape stage failed to reignite and stranded its payload, now called KOSMOS 60, in a low 125 by 178-mile (201 by 287-kilometer) parking orbit. The failed lander's orbit decayed five days later. Less than nine days later, the last Block III RANGER spacecraft was being prepared for launch. Unlike its sisters, RANGER D was going to be targeted for scientifically more interesting sites. The first two days of the lunar launch window did not offer any promising targets and no launch attempt was made. A launch on March 21 would allow an impact in the crater Alphonsus, which had shown some signs of apparent selenological activity in the recent past. A March 22 launch would land in the bright rayed crater Copernicus. March 23 would allow Kepler to be targeted, while a launch on either March 24 or 25 would permit an impact near Schroter's Valley. As it turned out, RANGER 9 lifted off on its first attempt on March 21, bound for a point at 13 degrees south, 2.5 degrees west, located in the crater Alphonsus. After AGENA 6007 completed its ninety-second injection burn, RANGER 9 was heading for a point only 400 miles (640 kilometers) north of its target. A 31-second burn of the course correction motor 38 hours, 26 minutes after launch added the 40.6 miles per hour (18.1 meters per second) needed to put RANGER 9 back on course. As the last RANGER was hurtling towards the Moon, the probe aligned its cameras with its flight path. Twenty minutes before impact, controllers sent commands to begin warming the cameras. Starting at an altitude of 1,300 miles (2,100 kilometers), RANGER 9 began transmitting the first of 5,814 pictures. The resolution steadily increased to as good as ten inches (25 centimeters) before the spacecraft slammed into the floor of Alphonsus at 13.3 degrees south, 3.0 degrees west, only four miles (6.5 kilometers) from its target. Surprisingly, the images returned by RANGER 9 indicated that while the lunar highlands were rougher than the maria, they were still smooth enough to be considered viable landing sites for future landing missions. Tracking of all four Block III RANGERs also indicated that the Moon's geometric center was displaced from its gravitational center. This fact was required to improve the accuracy of future lunar missions. After six years of effort, a total of 267 million dollars in funding (which would be close to one billion of today's dollars), much heartache over six failures, and much relief on three successes, NASA's first major lunar exploration program was ended. Efforts now turned to the other two legs of NASA's unmanned lunar triad, SURVEYOR and LUNAR ORBITER. The Big Push With the completion of the RANGER program, lunar exploration for the next fourteen months was dominated by the efforts of the Soviet Union. Their next launch occurred on May 9, 1965. This time the MOLNIYA booster vehicle operated as intended to place the 3,250-pound (1,476-kilogram) LUNA 5 on a trajectory towards the Moon. While no information was released on the spacecraft's design, this time there was no doubt of its intended mission: It was announced that LUNA 5 would attempt a soft lunar landing. A course correction the day after launch put the probe on target for the Moon. After 3.5 days of travel, LUNA 5 arrived at its target. At an altitude of 40 miles (64 kilometers), the onboard radar altimeter would trigger the retrorockets to slow the probe from 5,800 miles per hour (2,600 meters per second) to a virtual stop at the lunar surface. Then, at the moment the retrorockets were to fire, nothing happened. LUNA 5 crashed at 31 degrees south, 8 degrees west. Unphased by the loss, another probe was launched less than one month later. The 3,175-pound (1,442-kilogram) LUNA 6 was launched on June 8 and successfully placed on a translunar trajectory. As with its predecessor, LUNA 6 performed a mid-course correction the day after launch, after a dozen communication sessions with its controllers. However, unlike its sister craft, the probe malfunctioned at this point and the course correction engine continued to burn past its intended cutoff time despite desperate commands sent from controllers on Earth. As a result of this extra added impulse, LUNA 6 missed the Moon by about 100,000 miles (161,000 kilometers) and continued on into solar orbit. The Soviets were robbed of another success for the eighth time in two years. The new, second generation LUNA design apparently needed more work. The next lunar mission launched by the Soviets was flown by an entirely different type of spacecraft. Launched on July 18, ZOND 3 was flown as an engineering test of the same type of interplanetary probe unsuccessfully used on the MARS 1 and ZOND 2 missions to Mars in 1962 and 1964 respectively and the ZOND 1 mission to Venus in early 1964. Some in the West have speculated that ZOND 3 was originally meant to be launched with ZOND 2. The launch was canceled possibly because of last-minute problems, making ZOND 2 the only solo planetary mission the Soviets have ever launched. With three VENERA probes using this same design scheduled to be launched during the next Venus launch window in four months, Soviet engineers apparently wanted to test this design one last time using this "surplus" spacecraft to make sure they had worked out all the bugs in the design. This first generation interplanetary probe consisted of two compartments, the orbital compartment and the planetary compartment. The orbital compartment was the heart of the probe. This pressurized 3.6-foot (1.1-meter) diameter cylinder contained the probe's control systems, transmitters, batteries, thermal control, and astro-orien- tation systems, as well as some cruise experiment electronics. Mounted on top of the compartment was a 440-pound (200-kilogram) thrust KDU-414 propellant course correction engine capable of at least two burns, yielding a total velocity change of about 180 miles per hour (80 meters per second). Also located here was a nitrogen jet attitude control system to maintain control of the 12-foot (3.6-meter) long, three-axis stabilized probe. Mounted on the sides of this compartment were two solar panels used to recharge ZOND's batteries. While not needed for a short mission to the Moon, they were vital for an interplanetary mission. The panels had a total span of about thirteen feet (four meters) when deployed. On the ends of each panel were mounted large hemispherical radiators used to control the spacecraft's temperature. On the anti-Sun side of the craft, a 6.6-foot (two-meter) high-gain antenna was mounted. Also attached to this compartment were instruments to study micrometeoroids, cosmic radiation, low-frequency radio waves, and magnetic fields. And like its predecessor, ZOND 2, it also carried a set of experimental ion thrusters for use in attitude control tests. Mounted underneath the orbital compartment was the planetary compartment. This compartment would carry the instruments needed to study the target planet. Starting with the flight of VENERA 3, launched in November of 1965, these compartments were designed to detach from the orbital compartment and land on the surface of Venus. It is highly likely that the planetary compartment of ZOND 2 was of similar design and meant to land on the planet Mars. It is also possible that as many as four of the five unannounced failed attempts to reach Venus and Mars in 1962 - as well as ZOND 1 and KOSMOS 27, targeted for Venus in 1964 - carried similar payloads. The planetary compartment of ZOND 3 was different. It was designed to stay attached to the orbital compartment as the spacecraft flew by its target. Contained in this three-foot (0.9-meter) sphere were three experiments: A photo-television system capable of taking either photographs or ultraviolet spectra in the 250 to 350 nanometer range as well as ultraviolet and infrared spectrophotometers sensitive to the 190 to 270 nanometer and the three to four micron wavelength bands, respectively. An earlier version of this system was carried by MARS 1. It was also likely carried by one of the failed Venus attempts in late 1962 and possibly by either KOSMOS 27 or ZOND 1, instead of a lander, in early 1964. This compartment was virtually identical to the one carried by VENERA 2, launched in November. The spectrophotometers and ultraviolet spectrometer were originally designed to study planetary atmospheres, so they were of little use in a lunar mission. The 14-pound (6.5-kilogram) photo-television system, however, was to be invaluable on this mission. It was basically a much improved version of the system employed six years earlier by LUNA 3. Images from a single 106.4-millimeter focal length f/8 lens were focused onto one-inch (25.4-millimeter) film. A total of 25 exposures of one-thirtieth or one one-hundredth of a second were made. Using the same film, the ultraviolet spectrometer would expose the eighth, ninth, and tenth frames, bringing the total number of exposures up to 28. After the film was exposed, it was automatically developed on board. The dried negatives were then scanned and transmitted back to Earth in one of two formats. A quick look format broke the photograph into 67 lines that could be transmitted in 135 seconds. A more detailed scanning of the photographs was also possible. In this mode, each photograph was broken into 1,100 lines of 860 points each that were comparable in quality to RANGER's full scan television images. In this mode a single photograph could be transmitted over inter- planetary distances in 34 minutes. Each image could be scanned multiple times to help increase the image's signal-to-noise ratio. For this engineering test, ZOND 3 was targeted to flyby the Moon's western edge and photograph most of the Moon's far side missed during the historic LUNA 3 mission in late 1959. Unlike that mission, the lighting conditions and viewing angles were much more favorable for picking out details in this previously unmapped region. After its successful launch by a MOLNIYA launch vehicle, ZOND 3 headed towards the Moon. Since it only weighed two-thirds as much as the recent LUNA probes, ZOND 3 reached its rendezvous point 5,730 miles (9,220 kilometers) above the Moon after a flight of only 33 hours. Starting at a distance of 7,190 miles (11,570 kilometers), ZOND 3 took one exposure of the Moon every 134 seconds. Images included not only the unmapped far side but also the near side so that newly discovered features could be tied into the already existing lunar mapping control net. This continued as the fast-moving probe reached its closest point to the Moon and then receded to a distance of 6,190 miles (9,960 kilometers). After this 68-minute photography session, ZOND 3 immediately developed its film as it headed into a simulated trajectory to Mars - simulated since Mars was not in position for a low-energy encounter and would not be for another 1.5 years. On July 29, at a distance of 1.4 million miles (2.2 million kilometers), ZOND 3 was far enough for its high gain antenna to lock onto Earth and transmit back the recorded images to waiting scientists. The images were spectacular, far superior to the ones returned by LUNA 3. Details as small as three miles (five kilometers) across could be seen in the photographs, which showed little more than a cratered wasteland. These photographs confirmed that there was a lack of maria on the Moon's far side compared to the familiar near side, which was dominated by these dark and relatively flat expanses of ancient, hardened lava. The photographs also showed no signs of Mare Parvum, which some observers had claimed to see near Mare Orientale during especially extreme librations of the Moon. ZOND 3 discovered a new type of lunar feature called thalassoids. These were the battered concave-shaped remnants of basins over three hundred miles (five hundred kilometers) across and were thought to be the precursors of maria. For some reason these far side structures were never flooded with lava to form true maria. The other optical instruments onboard ZOND 3 showed that the Moon reflected one percent of the ultraviolet radiation hitting its barren surface. In contrast, the lunar surface reflected eighty to ninety percent in the incident infrared light, with a broad peak around 3.6 microns. With these photographs in hand, the Soviets had mapped all but five percent of the Moon's surface. ZOND 3 continued to operate as it traveled further from Earth. On September 19, at a distance of 7.8 million miles (12.5 million kilometers), ZOND 3 performed a burn of its KDU-414 engine to change its velocity by 112 miles per hour (50 meters per second) as part of a simulated mid-course correction. On October 23, at a distance of 19.6 million miles (31.5 million kilometers), ZOND 3 successfully retransmitted its photographs and probably did so again at still greater distances. The probe was tracked until it had receded to a distance of 95.4 million miles (153.5 million kilometers) in March of 1966, when contact was finally lost. It was a very successful test of this probe design. At 225-plus days, ZOND 3 was also the longest-surviving Soviet lunar or planetary probe to date, beating the previous record holder, MARS 1, by almost three months. Ironically, its Venus-bound sister probes did not fare as well. VENERA 2, launched on November 12, which carried the same instruments as ZOND 3, failed just as it was to perform its photo- graphing session of Venus on February 27, 1966, after a flight of ------------------------------ End of Space Digest Volume 15 : Issue 156 ------------------------------