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Space Digest Thu, 12 Aug 93 Volume 17 : Issue 015 Today's Topics: Electronic Journal of the ASA (EJASA) - August 1993 * FOURTH YEAR! [Part 1] Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space <your name>" 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: Wed, 11 Aug 1993 19:04:44 GMT From: Larry Klaes <klaes@verga.enet.dec.com> Subject: Electronic Journal of the ASA (EJASA) - August 1993 * FOURTH YEAR! [Part 1] Newsgroups: sci.astro,sci.space,sci.misc,sci.geo.geology,sci.environment,talk.environment,talk.politics.space,alt.sci.planetary THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC Volume 5, Number 1 - August 1993 ########################### TABLE OF CONTENTS ########################### * ASA Membership and Article Submission Information * The Great Moon Race: The Tide Turns - Andrew J. LePage * The Concept of "Billboards in Space" - Earl W. Phillips ########################### 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 (the JASA is a hardcopy sent through United States Mail and is 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) P. O. Box 15038 Atlanta, Georgia 30333-9998 U.S.A. asa@chara.gsu.edu ASA BBS: (404) 321-5904, 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 - Eric Greene Vice President - Jeff Elledge Secretary - Ingrid Siegert-Tanghe Treasurer - Mike Burkhead Directors - Becky Long, Tano Scigliano, Bob Vickers Council - Bill Bagnuolo, Michele Bagnuolo, Don Barry, Bill Black, Mike Burkhead, Jeff Elledge, 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 the ASA anonymous FTP site at chara.gsu.edu (131.96.5.29). Directory: /ejasa 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. No responsibility is assumed by the ASA or the EJASA for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use of operation of any methods, products, instructions, or ideas contained in the material herein. This Journal is Copyright (c) 1993 by the Astronomical Society of the Atlantic, Incorporated. THE GREAT MOON RACE: THE TIDE TURNS Copyright (c) 1993 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. By the late spring of 1966, the United States was ready to launch its second lunar lander series, named SURVEYOR. The ATLAS-CENTAUR rocket, despite its development problems, was deemed ready to hurl the new spacecraft to the Moon via a direct ascent trajectory. Even though the Soviets had beaten the Americans to the lunar surface with LUNA 9, it was hoped that SURVEYOR would ultimately surpass its Soviet competitor. In private, the people involved with the SURVEYOR project hoped that it would just succeed at retrorocket ignition. While much testing had been done, certain aspects of the mission - such as how the lander would handle during retro fire and how the lander's radar would interact with the lunar surface - could only be determined by an actual flight. The chances for success on the first mission were considered low. America's Fourth Lunar Landing Attempt On May 30, 1966, ATLAS-CENTAUR 10 lifted off from Launch Pad 36A at Cape Kennedy (now Cape Canaveral) and placed the 2,194-pound (996-kilogram) SURVEYOR 1 on a direct ascent trajectory to the Moon. A landing site in Oceanus Procellarum was chosen to allow SURVEYOR 1 to make the easiest approach to the Moon: Virtually straight down. Sixteen hours after launch the spacecraft performed a 21-second course correction burn using its three vernier engines to correct the 250-mile (400-kilometer) aiming error. Except for indications that one of the two low-gain antennae (LGA) had not fully deployed, all was proceeding as planned. The lander was expected to touch down after a flight of 63.6 hours. On June 2, SURVEYOR 1 obediently aligned its retrorocket along the flight path. At an altitude of 59.35 miles (95.49 kilometers), the marking radar mounted in the retrorocket nozzle locked onto the return signal from the lunar surface. Seven seconds later, the retrorocket ignited at a height of 46.75 miles (75.22 kilometers) as the lander reached a speed of 5,840 miles per hour (2,610 meters per second). After its 42-second burn, the speed was cut to 250 miles per hour (110 meters per second) and the verniers were throttled up to full thrust. Ten seconds later the empty retrorocket was discarded. By the time the altitude was cut to fourteen feet (4.3 meters), the robot's speed had fallen to three miles per hour (1.4 meters per second). The verniers were then shut down, allowing the lander to touch down at a speed of seven miles per hour (three meters per second). After a one-second, 2.6-inch (6.5-centimeter) high bounce, SURVEYOR 1 finally came to rest at 2.45 degrees south latitude, 43.22 degrees west longitude near the crater Flamsteed. SURVEYOR 1 had succeeded on the first try and landed only 8.7 miles (14 kilometers) off target! After returning 36 minutes of engineering data to check on the lander's condition (which indicated that the previously stuck low-gain antenna snapped into place as a result of the landing impact), SURVEYOR 1 returned its first 200-line television image. This picture and the 10,731 others taken that first lunar day revealed that SURVEYOR 1 had landed on the inside of a 60-mile (100-kilometer) wide "ghost" crater that had been filled with molten rock eons ago. The landing site was littered with such boulders ranging up to one yard (one meter) across and craters of various sizes and states of preservation. The pictures and the engineering data from the landing indicated that the footpads had sunk only one inch (2.5 centimeters) into the granular lunar soil. The surface was more than firm enough to hold the weight of a manned lander and its human occupants. As the Sun sank below the lunar horizon on June 14, SURVEYOR 1 was put into hibernation in hope that the probe would survive the minus 255 degree Fahrenheit (-160 degree Celsius), fourteen terran day-long lunar night. Although initial attempts at contact on June 28 failed, the lander responded to commands on July 6, returning another 618 images during its second lunar day of operations. On July 13, the battery voltage dropped dramatically as the Sun set once again. While intermittent contact was maintained with the spacecraft until January 7, 1967, the mission was effectively over at the end of the second lunar day due to the worsening condition of the battery. All together, SURVEYOR 1 responded to 297 commands enroute to the Moon, 134,216 commands during its 219 terran days on the lunar surface, and returned 11,150 useful television images. The first SURVEYOR was an outstanding success. The tide had finally turned for the American lunar program. LUNAR ORBITER At the same time SURVEYOR 1 was performing its duties on the lunar surface, the first LUNAR ORBITER (LO) spacecraft was being prepared for launch on its ATLAS-AGENA D rocket. LUNAR ORBITER was designed for a single task: Orbit the Moon and take high-resolution images of the lunar surface in order to identify potential APOLLO landing sites. The 850-pound (385-kilogram) spacecraft was designed around an 147- pound (67-kilogram) photographic system built by Eastman-Kodak. This system, based on Kodak's previously classified Department of Defense (DoD) work, was housed in an ellipsoidal aluminum alloy shell pressurized with dry nitrogen at 1.7 pounds per square inch (120 mil- libars). Viewing through a quartz window in the side of the shell were a wide-angle three-inch (eighty-millimeter) focal length, f/4.5 lens and a 24-inch (610-millimeter) focal length, f/5.6 narrow angle lens. These lenses simultaneously produced a pair of images on seventy- millimeter Kodak SO-243 high-contrast, fine grain aerial mapping film using exposures of 1/25th, 1/50th, or 1/100th of a second. Some 260 feet (79 meters) of film were carried aboard LO, allowing as many as 212 image pairs to be taken. The 610-millimeter lens was also used by an electro-optic velocity/height sensor that slowly slewed the cameras during an exposure to compensate for the motion of the spacecraft as it orbited the Moon. During its fifteen to thirty day- long photography mission in a 29 by 1,150-mile (47 by 1,850-kilometer) mapping orbit, the best resolution for the narrow and wide-angle images was expected to be one and eight yards (one and eight meters), respec- tively. This film was developed as the photographs were taken using Bimat Transfer Film, which employed spools of a webbing impregnated with the appropriate developing and fixing chemicals. Since the photographs could be taken faster than they could be processed, a set of takeup reels were included, allowing up to 21 image pairs to be stored. Once all the images were taken and the film was developed, the negatives were scanned by a 0.2 millimeter (5 micron) wide beam of high intensity light at a resolution equivalent of 7,300 lines per inch (287 lines per millimeter). A photomultiplier tube detected the light beam, whose intensity was modulated by the film's density, and the appropriate electronics converted this signal into a form to be transmitted back to Earth. Each image pair could be transmitted in 43 minutes when both the Earth tracking station and the Sun were visible. The scanned photographs were the equivalent of a 8,360 by 9,880 pixel image for the wide-angle and a 8,360 by 33,288 pixels for the narrow-angle views. One of the primary reasons for choosing this photographic system over a scanned vidicon camera with magnetic tape storage was because of the incre- dible resolution and enormous data storage capabilities this technique offered, even by present standards. This photographic system was mounted on the spacecraft's 4.6-foot (1.4-meter) diameter equipment deck at the base of the 6.6-foot (2.0- meter) tall, roughly conical-shaped spacecraft. Also mounted on this deck were a Canopus star sensor, five Sun sensors, and an inertial reference unit all used to determine LUNAR ORBITER's attitude to an accuracy of 0.2 degrees. A flight programmer possessed a 128-word memory that was able to control spacecraft activities for sixteen hours worth of photography. Under the control of this unit, the photographic system could be programmed to take groups of four, eight, or sixteen photographs of selected sites per orbital pass. Data were returned via a boom-mounted, three-foot (92-centimeter) diameter high-gain dish antenna. A ten-watt transmitter would use this to transmit the images back to Earth. A low-gain antenna, dedicated to a one-half watt transmitter, was also mounted on the equipment deck opposite the high-gain antenna. It was used to return telemetry. Four solar panels, spanning a total of seventeen feet (5.2 meters), were also mounted here to provide the orbiter with 375 watts of electricity. When the spacecraft was in shadow, power was provided by nickel-cadmium batteries. Mounted on an open truss frame above the equipment deck was the upper structural module. This unit housed the velocity control engine used to place LUNAR ORBITER in orbit as well as trim that orbit once there. This engine, based on the APOLLO attitude control thruster, produced 100 pounds (445 newtons) of thrust using the hypergolic propellants hydrazine and nitrogen tetraoxide. These propellants were stored in tanks also located in the upper structural module. Eight nitrogen gas jets mounted at the top of the spacecraft provided attitude control. For thermal control, the entire spacecraft was shrouded in a blanket of aluminized mylar. The underside of the equipment deck, which would normally face the Sun, was covered with a white thermal paint. These measures were expected to maintain the orbiter's temperatures between 36 and 84 degrees Fahrenheit (2 and 29 degrees Celsius). The only other instruments carried by LUNAR ORBITER were a ring of twenty pressurized meteoroid detectors and a pair of dosimeters to assess any radiation hazards to manned spacecraft in the near-lunar environment. By monitoring the orbital changes of the spacecraft, the mass distribution of the Moon could also be mapped. This knowledge would be essential for the pinpoint accuracy needed for the APOLLO landing missions. While the photographic portion of the mission was expected to last no more than one month, these other investigations would employ the spacecraft for up to one year. America's Seventh Lunar Orbiter Attempt America's seventh attempt to send a spacecraft into lunar orbit did not involve LUNAR ORBITER whatsoever. That distinction falls to a little-known spacecraft built and operated by NASA's Goddard Space Flight Center (GSFC) called EXPLORER 33. This spacecraft was the fourth in their Interplanetary Monitoring Platform (IMP) series. Starting with the launch of EXPLORER 18 on November 26, 1963, this program's goal was to place satellites, loaded with particle and fields instrumentation, into highly eccentric orbits in order to study the planet Earth's magnetosphere and its interaction with the Sun-dominated interplanetary environment. EXPLORER 33 was to be the first "Anchored" IMP. The anchor was to be the Moon. From this vantage point, EXPLORER 33 could continuously monitor the radiation and magnetic field environment from lunar dis- tances, unlike the previous IMPs which would periodically swing back towards Earth in their elongated geocentric orbits. A secondary objective for this Anchored IMP was to study the Moon's effect on this environment as well as the lunar gravitational field. The 205.7-pound (93.4-kilogram) spacecraft consisted of an eight- inch (twenty-centimeter) tall octagonal bus 28 inches (71 centimeters) across. It was topped by an 81-pound (37-kilogram) solid propellant retrorocket that would produce 916 pounds (4,080 newtons) of thrust for 20 to 22 seconds. Mounted on the bus were four solar panels producing 43 watts of electrical power and a pair of six-foot (1.8-meter) long magnetometer booms. A seven-watt transmitter inside the bus made use of four external whip antennae for communications. Also mounted inside were six particle and fields experiments and a data processor. The probe spun at twenty revolutions per minute for attitude control but had no provisions for mid-course corrections. Instead, EXPLORER 33 would rely on the accuracy of its DELTA E - also known as the DSV-3E1 or THRUST AUGMENTED DELTA - launch vehicle to place it on the correct trajectory to enter a 810 by 4,000-mile (1,300 by 6,400- kilometer) lunar orbit inclined 175 degrees to the equator and having a period of about ten hours. The DELTA E was the latest in NASA's ever-improving DELTA launch vehicle family that was originally based on the infamous THOR-ABLE booster that had failed so miserably in launching the early PIONEER lunar orbiters. Unlike its highly unreliable ancestor, the DELTA had proven to be NASA's most reliable rocket, with 35 successful launches in 38 attempts since its first flight on May 13, 1960. The DSV-3E1 DELTA variant was vastly different from the THOR- ABLE. The engines in the enlarged first and second stages were up to seventeen percent more powerful and much more reliable and efficient than before. The more powerful Hercules X-258 solid rocket motor replaced the old ABL X-248 motor used previously in the third stage. Most importantly, three Thiokol built Castor 1 solid rocket boosters were strapped to the side of the first stage, giving the DELTA E a total liftoff thrust of 331,850 pounds (1,477 kilonewtons). Not as evident as these exterior changes, inside the launch vehicle was equipped with totally new guidance and control systems. Despite all the upgrades and significant increase in reliability, it was recognized from the start that there was a fairly good chance that EXPLORER's launch vehicle could place the probe on a trajectory that could be off by just enough so that, without a mid-course correction capability, EXPLORER could not enter lunar orbit. On July 1, 1966, EXPLORER 33 lifted off from Pad 17A at Cape Kennedy. As luck would have it, the DELTA's second and third stages worked slightly better than designed and imparted an excess velocity of 47.7 miles per hour (21.3 meters per second) to EXPLORER 33, resulting in a 9,880 by 270,560-mile (15,897 by 435,330-kilometer) geocentric orbit. Although the second and third stages worked well within specifica- tions, this excess velocity was just enough so that EXPLORER 33 could not enter lunar orbit. Instead, ground controllers fired the tiny EXPLORER's rocket motor to place the IMP into a 18,987 by 279,163- mile (30,550 by 449,174-kilometer) Earth orbit where EXPLORER 33 would conduct an alternate mission similar to previous IMPs. Another attempt to launch an Anchored IMP was scheduled for one year later. America's First Lunar Orbiter America's eighth attempt to send a probe to orbit the Moon, LUNAR ORBITER 1, was finally launched on August 19, 1966 from Pad 13 on Cape Kennedy using an ATLAS-AGENA D booster. The primary objective of this flight was to photograph nine potential APOLLO landing sites and seven secondary sites. Efforts would also be made to locate the SURVEYOR 1 lunar lander then completing its third lunar day on the surface. After coasting in its 100-mile (160-kilometer) high Earth parking orbit for 28 minutes, the Bell 8096 engine of the AGENA D came to life again for a ten-minute burn that would send LUNAR ORBITER towards the Moon. After the spacecraft separated from its escape stage, LO unfolded its solar panels and antennae and proceeded to find its celestial at- titude references. While the Sun was located without trouble, the Canopus star sensor failed to lock onto its target to provide the spacecraft with its needed roll reference. Apparently stray sunlight was being reflected from an unexpected location into the sensor. Instead, the brilliant Moon itself was used for a reference for the next two days until an alternate acquisition method could be devised. Twenty-four point-seven hours after launch, LUNAR ORBITER 1 performed a course correction burn to place it within fifty miles (eighty kilometers) of its target point above the Moon. About 67 hours later, LUNAR ORBITER 1 fired its engine once again for 578.7 seconds to cut its approach speed by 1,766.8 miles per hour (789.65 meters per second). With this burn, LUNAR ORBITER entered a 119 by 1,152-mile (191 by 1,854-kilometer) orbit around the Moon inclined 12.2 degrees to the lunar equator and having a period of three hours and 37 minutes. Tracking quickly revealed that the orbit was changing quite quickly because of the relatively large variations in the lunar gravitational field. The origin of these irregularities was unknown at the time. Later it was found these orbit changes were being caused by approximately one dozen near-surface mass concentrations, abbreviated "mascons". Once in orbit, LUNAR ORBITER 1 took a series of twenty engineering images between August 18 and 20 of both sides of the Moon to check out the imaging system between. On August 21, the main engine was again fired to lower the periapsis of the orbit down to 31 miles (fifty kilometers) in preparation for actual mapping, which began the next day. The periapsis was lowered again on August 25 to an altitude of 25 miles (forty kilometers). While the initial wide angle images images had shown the system was working well, the high resolution images were hopelessly blurred because of a failure in the velocity/ height sensor. Despite this failure, and some temperature control problems, 75 percent of the objectives were met and the mission was deemed a success. By August 30, LUNAR ORBITER used the last of its 211 exposures of film. The images returned in the following days had shown that the lunar surface was capable of supporting a lander due to the presence of large boulders in various areas. The landing area of SURVEYOR 1 also seemed to have twenty percent fewer craters than other lunar maria, making it a good candidate of a manned landing. Low resolution images taken of the unseen farside of the Moon confirmed observations made by the Soviet LUNA 3 and ZOND 3 probes in 1959 and 1965, respectively, that this region of the Moon was almost completely devoid of large maria that dominate the familiar lunar near side. During LUNAR ORBITER's eight weeks in orbit, not a single micrometeoroid impact was recorded, compared to the four that would be expected if the experiment were conducted in Earth orbit. The measured radiation dose was as predicted before the flight and would not prove to be a problem for a manned flight. On October 29, LUNAR ORBITER 1, after completing 577 orbits, fired its main engine one last time for 97 seconds. This allowed the spacecraft to drop from lunar orbit and crash at 6.7 degrees north latitude, 162 east longitude. This was done so that transmissions from the probe would not interfere with the next LUNAR ORBITER, due for launch within the next week or so. After eight attempts in eight years, the Americans had their first successful lunar orbiter mission. The Soviets Return Two weeks after the launch of LUNAR ORBITER 1, the Soviet Union launched their third known orbiter attempt, LUNA 11. On August 27, the 3,611-pound (1,640-kilogram) spacecraft slipped into a 101.6 by 741.8-mile (163.5 by 1,193.6-kilometer) lunar orbit inclined 27 degrees to the equator. The exact configuration and payload of this orbiter have never been revealed by the Soviets. It does appear that the bus and payload did not separate once in lunar orbit as was the case with LUNA 10. Instead they remained together with the bus providing attitude control. Fields and particle data were apparently returned. It was reported that image transmissions similar to those from LUNA 9 were intercepted at the radio observatory in Jodrell Bank in Great Britain. Since the Soviets never mentioned photography as a mission goal, it is possible that this experiment failed if indeed it was even carried at all. Whatever the mission of LUNA 11 was, the Soviet probe continued to function until October 1, when the batteries became exhausted. During its five weeks in orbit, LUNA 11 completed 277 revolutions around the Moon. Before LUNA 11 fell silent, the American SURVEYOR 2 was prepared for launch. On September 20, ATLAS-CENTAUR 7 flawlessly lifted off from Cape Kennedy and placed the 2,204-pound (1,001-kilogram) lander on a trajectory to land in Sinus Medii near the center of the Moon's near side. Unlike SURVEYOR 1, which approached the lunar surface from a mere six degrees to the local vertical, SURVEYOR 2 would have to contend with a 23-degree approach angle in order to land. Sixteen and one-half hours after launch, SURVEYOR 2 proceeded to align itself to make a 9.8-second course correction burn using its three vernier engines. Unfortunately, one of these engines failed to ignite, sending SURVEYOR 2 into a sixty-revolution per minute tumble. Attempts to halt this tumble using the nitrogen attitude jets failed; the rotation rate was far beyond their correction capability. After 39 unsuccessful attempts to start the malfunctioning vernier engine, the mission was declared a loss. The mission planners decided to obtain as much engineering information as possible before impact. Commands were sent from the tracking station in Canberra, Australia, for SURVEYOR 2 to vent its helium propellant tank pressurant, erect its solar panel, and turn on its radar. The solid retrorocket was fired as the tumbling probe approached the surface. After firing for thirty seconds, contact with SURVEYOR 2 was lost as it slammed into the lunar surface at an estimated 6,000 miles per hour (2,700 meters per second) at 5.5 degrees north, 12.0 degrees west near the rayed crater Copernicus. On October 22, the Soviets launched yet another lunar orbiting probe. LUNA 12 left its 123 by 132-mile (199 by 212-kilometer) parking orbit and performed a single course correction burn the following day. On October 25, LUNA 12 fired its KTDU-5A engine for 28 seconds to decrease its 4,665 mile per hour (2,085 meter per second) approach speed by 2,096 miles per hour (937 meters per second) and enter a 83 by 750 mile (133 by 1,200 kilometer) orbit inclined ten degrees to the lunar equator. Unlike the previous mission, this time there was no doubt as to the mission of LUNA 12: This was a mapping mission likely supporting the Soviet manned lunar landing program then secretly under development. Like LUNA 11, the payload of LUNA 12 stayed attached to the main bus. This payload was dominated by a large conical instrument compartment with its radiator mounted on top of the bus. Below this were extra spheres containing pressurized nitrogen for the attitude control system. Inside the instrument compartment above the radiator were experiments to detect gamma rays from the lunar surface, measure the magnetic and radiation near the Moon, an infrared radiometer, and meteoroid detectors. Mounted on the side of the bus where the radar altimeter would be in a landing mission was a photographic package virtually identical in operation and capability to the one carried by ZOND 3 the previous year. In the few images released to the public, it appears that this system was capable of returning images with a maximum resolution of 50 to 65 feet (15 to 20 meters). Transmissions of these images began on October 29. Once its photography mission was completed, LUNA 12 was set spinning slowly about its roll axis in order to better perform its particle and fields measurements. In addition to these scientific instruments, LUNA 12 also carried an engineering experiment. Unknown in the West at the time, a series of electric motors were carried into lunar orbit and tested. These motors were to be used by an unmanned lunar rover then under develop- ment as one part of the Soviets third generation of LUNA probes, to be launched in another two years. This next series of lunar probes would make use of the PROTON launch vehicle then under development to support the Soviets' manned circum-lunar program and would weigh 3.5 times more than the current generation of lunar probes. Their mission was to act as precursors to a Soviet manned landing, expected around 1971, as well as work in conjunction with these missions once they started. In many ways the third generation LUNAs were similar in their mission and size to the proposed American PROSPECTOR project, canceled three years earlier due to budget constraints. In the meantime, LUNA 12 continued its mission until January 19, 1967, when its batteries were finally exhausted. More Missions On November 6, 1966, just twelve days after LUNA 12 slipped into lunar orbit, the Americans launched LUNAR ORBITER 2 towards the Moon. Its mission was to photograph thirteen primary and seventeen secondary sites located in the southern part of the near side equatorial region. Several modifications were made to LUNAR ORBITER 2 as a result of problems with the previous mission. The camera system's shutter trigger circuits were modified to make them less susceptible to noise. To prevent the problem of stray reflections, which wreaked havoc with the Canopus star sensor, the end of the low-gain antenna as well as the edges and backs of the four solar panels were coated with anti- reflective black paint. To overcome thermal problems resulting from paint degradation, a new paint was applied to the Sunward side of the equipment deck. In addition, three metal coupons coated with other paints and an instrumented mirror were carried to evaluate their usefulness in case the new paint also did not perform as well as required. After making a 51-mile per hour (23-meter per second) course correction on November 8, LUNAR ORBITER 2 successfully entered a 122 by 1,163-mile (196 by 1,871-kilometer) lunar orbit inclined 12.2 degrees on November 10. Another burn five days later lowered the periapsis to 31.4 miles (50.5 kilometers), so that the actual mapping mission could begin on November 18. After one solid week of mapping involving 205 attitude changes, the mapping mission was completed and the transmis- sion of images began. A failure in high-gain transmitter on December 6 resulted in the loss of the last two high resolution and the last three medium resolution images showing APOLLO Site 1. Despite this minor loss, this mission did take the most memorable image of the whole series. Even if there was no target of interest to photograph, the film in the photographic system had to be advanced every four to eight hours so that it would not stick to the Bimat webbing. These opportunities were usually used to take images of the lunar farside or additional views of the front. For one of these photographs, LUNAR ORBITER 2 took an oblique image across the crater Copernicus from an altitude of 28.5 miles (45.9 kilometers). For the first time, the Moon was seen by the public as a three-dimensional place with rugged mountains and smooth plains. At the time newspapers dubbed the photograph "The Picture of the Century". In addition to this and other photographs, the LUNAR ORBITER 2 meteoroid detector recorded only three hits, indicating that the micrometeoroid threat was virtually non-existant in lunar orbit. On December 8, with its mapping mission complete, LUNAR ORBITER 2 fired its engine again for 62 seconds to increase its inclination to 17.5 degrees. This allowed the orbiter to fly over a larger latitude range in order to study lunar mascons and provide tracking experience. Another three-second burn on April 14, 1967 shortened the orbital period by 65 seconds, reducing the time the spacecraft would spend in darkness during the lunar eclipse ten days later. A final burn on October 11, 1967 chopped 160 miles per hour (71 meters per second) off of LUNAR ORBITER's velocity, allowing it to crash at 4 degrees south, 98 degrees east. So ended a second successful mapping mission. Last Call As the year 1966 was drawing to a close, the Soviets left no doubt who started this banner year for lunar exploration. On December 21, LUNA 13 was launched first into a 106 by 145-mile (171 by 233-kilometer) Earth parking orbit and then on towards the Moon. Unlike the previous three acknowledged Soviet missions which went into lunar orbit, LUNA 13 was headed for another lunar landing. After a course correction the day after launch, LUNA 13 made its final approach and landed on Christmas Eve, only 250 miles (400 kilometers) from LUNA 9 at 18.57 degrees north, 60.00 degrees west. The 240-pound (109-kilogram) LUNA 13 lander was very similar to its sister, LUNA 9, but carried several additional experiments to study the properties of the Moon. Inside the spherical lander was carried a three- axis accelerometer to record the landing forces. This information would allow studies of the surface structure to a depth of eight to twelve inches (twenty to thirty centimeters) below the surface. Two five-foot (1.5-meter) long booms were also deployed upon landing. One boom carried a penetrometer consisting of a titanium- pointed, two-inch (five-centimeter) long, 1.4-inch (3.5-centimeter) wide rod. A small explosive charge applied sixteen pounds (seventy newtons) of force to this rod for 0.6 to 1.0 seconds, pushing it into the dusty surface five minutes after landing. The rod penetrated 1.8 inches (4.5 centimeters) into the lunar soil, indicating that it was a granular mixture with a density of 0.8 grams per cubic centimeter. The second boom contained a radiation densitometer using a cesium-137 gamma-ray source and three detectors. By the way the gamma rays were scattered, the density of the soil could be determined. This experiment confirmed the results of the penetrometer to a depth of six inches (fifteen centimeters). Four radiometers were also mounted around the capsule's circumference. They indicated that the surface temperature was about 243 degrees Fahrenheit (117 degrees Celsius). A radiation detector mounted next to the panoramic camera measured the surface radiation environment. It showed that one-quarter of the cosmic radiation hitting the Moon is reflected from the surface. A total of five images were returned by the 3.7-pound (1.7-kilogram) camera during the mission. Because of the location of the new radiation detector, the camera could now only scan through 220 degrees of azimuth. Still, the images showed that LUNA 13 came to rest at a sixteen-degree angle in a featureless plain with only a few stones poking through the soil. Surface operations continued until the batteries were finally depleted of energy on December 30. Unknown to those in the West, this would be the last second generation LUNA landing mission. It was also a fitting end to the busiest year to date in lunar exploration. The following year, 1967, would prove to be even busier with already planned American missions. However, budget constraints caused by the ever-increasing needs of the APOLLO project (not to mention the conflicts in Southeast Asia and domestic social programs) had effectively killed any future plans for unmanned lunar exploration by the United States. On December 13, 1966, NASA cancelled all plans for additional, more heavily instrumented SURVEYOR flights after the seventh mission. This decision just added to the scramble to include whatever advanced experiments possible on the five remaining SURVEYOR flights. Plans for a gamma-ray spectrometer-equipped LUNAR ORBITER were also scuttled. After 1967, American scientist would have to rely on the highly political, engineering oriented APOLLO missions for new information on the Moon. For now, though, there was still 1967. Summary of Lunar Probe Launches, Second to Fourth Quarter 1966 ____________________________________________________________________________ Name Launch Date Country Weight lbs (kg) Launch Vehicle ____________________________________________________________________________ SURVEYOR 1 May 30, 1966 US 2,191 (995) ATLAS-CENTAUR Lunar landing EXPLORER 33 Jul 1, 1966 US 205.7 (93.4) DELTA E Unsuccessful lunar orbiter attempt LUNAR ORBITER 1 Aug 10, 1966 US 852 (387) ATLAS-AGENA D Photographic lunar orbiter LUNA 11 Aug 24, 1966 USSR 3,611 (1,640) MOLNIYA Lunar orbiter SURVEYOR 2 Sep 20, 1966 US 2,204 (1,001) ATLAS-CENTAUR Unsuccessful lunar landing LUNA 12 Oct 22, 1966 USSR 3,567 (1,620) MOLNIYA Photographic lunar orbiter LUNAR ORBITER 2 Nov 6, 1966 US 859 (390) ATLAS-CENTAUR Photographic lunar orbiter LUNA 13 Dec 21, 1966 USSR 3,567 (1,620) MOLNIYA Lunar lander ____________________________________________________________________________ Bibliography - Davies, Merton E., and Bruce C. Murray, THE VIEW FROM SPACE, 1971 Gatland, Kenneth, ROBOT EXPLORERS, 1972 Gatland, Kenneth, ILLUSTRATED ENCYCLOPEDIA OF SPACE TECHNOLOGY, 1988 Johnson, Nicholas, HANDBOOK OF SOVIET LUNAR AND PLANETARY EXPLORATION, 1979 Mirabito, Michael M., THE EXPLORATION OF OUTER SPACE WITH CAMERAS, 1983 Wilson, Andrew, (JANE'S) SOLAR SYSTEM LOG, 1987 Wilson, Andrew (Editor), INTERAVIA SPACE DIRECTORY 1989-1990 MAJOR NASA LAUNCHES, KSC Historical Report No. 1A, circa 1989 "Spacecraft Details", TRW SPACE LOG, Summer 1966, Winter 1966-1967 VECTORS, Volume X: SURVEYOR Commemorative Issue, 1968 About the Author - Andrew J. LePage is a scientist at a small R&D company in the Boston, Massachusetts area involved in space science image and data analysis. He has written many articles on the history of spaceflight and astronomy over the past few years that have been published in many magazines throughout North America and Europe. Andrew has been a serious observer of the Soviet/CIS space program for over one dozen years. Andrew's Internet address is: lepage@bur.visidyne.com Andrew is the author of the following EJASA articles: "Mars 1994" - March 1990 "The Great Moon Race: The Soviet Story, Part One" - December 1990 "The Great Moon Race: The Soviet Story, Part Two" - January 1991 "The Mystery of ZOND 2" - April 1991 "The Great Moon Race: New Findings" - May 1991 "The Great Moon Race: In the Beginning..." - May 1992 "The Great Moon Race: The Commitment" - August 1992 "The Great Moon Race: The Long Road to Success" - September 1992 "Recent Soviet Lunar and Planetary Program Revelations" - May 1993 "The Great Moon Race: The Red Moon" - July 1993 THE CONCEPT OF "BILLBOARDS IN SPACE" by Earl W. Phillips "Billboards in Space" is the generic name for any proposal to launch into low Earth orbit (LEO) platforms which would be visible from Earth's surface at night and which carry commercial advertising. A movement has begun within the astronomical community to stop the idea of "Billboards in Space" before it ever gets a chance to literally fly. The movement began after news of just such an idea was proposed by the Roswell, Georgia firm Space Marketing, Inc. Their proposal has generated volumes of press releases, letters, and articles in opposition. All of the articles I have read so far say almost the same thing: A one-mile (0.6-kilometer) long Mylar-covered platform will be boosted into LEO in 1996, rivaling the Moon in full phase in both apparent size and brightness, displaying commercial advertising. The proposal began as a way to hype the 1996 Summer Olympic Games, to be held in Atlanta, Georgia. Dubbed "The Environmental Platform" by its creators, it is planned to carry a battery of ozone reading monitors. According to a telephone and fax interview I conducted with Space Marketing, Inc.'s CEO Mike Lawson: "The advertising part of the plat- form has been blown out of proportion by the astronomical community and the press. It will not display commercial advertising, but rather a symbol that represents recycling and the wise use of Earth's resources. Any company that wishes to may purchase rights to the logo and print it on their products, thus identifying themselves with the message the logo intends to foster." Also, rather than being visible at night, Lawson states that the platform "would be visible only during daylight hours, and then only for ten to fifteen minutes out of every ninety." Further, he states that the platform is expected to last only "fourteen to twenty days, after which time it will simply burn up in the upper atmosphere." The reason for the ozone monitoring instrumentation, according to Lawson, "is the fact that current ozone monitoring instrumentation is rapidly nearing the end of their useful lives and would otherwise have to be replaced at taxpayer expense." Lawson feels that his company's proposal will "effectively replace the current monitors at zero expense to the taxpayer, because the entire cost will be borne by the companies purchasing the rights to display the environmentally-friendly logo. In light of the current concentration on lowering the Federal deficit, it makes sense to shift as much of the burden as possible off the backs of the taxpayers". Lawson testified before a Senate Sub-Committee on his proposal the week of July 26, 1993. Congress has also taken issue with such proposals. Senate Bill Number S-1145, jointly introduced by Vermont Republican Senator James Jeffords and Massachusetts Democratic Representative Ed Markey, entitled the "Space Advertising Prohibition Act", declares that "the use of outer space for advertising purposes is not an appropriate use of outer space and should be prohibited." Other lawmakers and lawyers, however, feel that the bill is poorly worded and will therefore be difficult to uphold. As currently worded, it outlaws "all advertising in outer space, for purposes of ------------------------------ End of Space Digest Volume 17 : Issue 015 ------------------------------