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Date: Wed, 11 Aug 1993 19:13:37 +0000 (GMT)
From: klaes@verga.dnet.dec.com (Larry Klaes)
Subject: Electronic Journal of the ASA (EJASA) - August 1993 * FOURTH YEAR!
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Keywords: EJASA, ASA
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
marketing or otherwise promoting the sale or use of goods and
services." As Glenn Reynolds, Executive Vice President of the
National Space Society (NSS) and law professor at the University of
Tennessee, puts it: "This bill is a law professor's nightmare. If
one of my students had drafted this, I'd have given him an F, because
the definition of space advertising is so broad, it basically outlaws
everything - TV commercials, company logos on the sides of rockets,
the works. It's sloppy."
Obviously, any proposal that would add to the growing influence of
light pollution should rightly be fought. Astronomers have a tough
enough time as it is these days plying their trade through the current
flood of light pollution. Astronomy educators are finding it
increasingly difficult to teach the wonders of the heavens when fewer
and fewer stars are available to view. While this particular proposal
does not seem all that bad on the face of it, there will be proposals
submitted within the next five years that will directly affect the
night time light pollution.
I urge everyone to get ready to battle these future proposals if
you wish to continue seeing the stars at all. The best way is to let
our elected officials know how we feel on the subject. Contact the
elected representatives of your state, province, or country and let
them know that you refuse to allow the night sky to become a background
for commercial advertising. You can also leave a telephone message for
U.S. Vice President Al Gore at (202) 456-1111, from 9 a.m. to 5 p.m.
Eastern Time (ET). As the self-proclaimed "environmentally-friendly
Vice President", this is an excellent litmus test.
For further information on this particular proposal, or others
along the same vein, you may contact the author, Earl W. Phillips,
Jr., by U.S. Mail at 7893 Thornfield Lane, Columbus, Ohio 43235; or
by telephone from 6 p.m. to 10 p.m. Monday through Friday, and 10
a.m. to 10 p.m. on the weekends at (614) 764-0476.
Light/Space Pollution Education: Getting Started
If you are interested in stopping light and space pollution,
perhaps the first thing to do is join the International Dark-Sky
Association (IDA). They have a large collection of "information
sheets" that are packed with lots of detail, ideas, and data.
The IDA address is:
International Dark-Sky Association
Dave Crawford, Executive Director
3545 N. Stewart
Tucson, Arizona 85716
U.S.A.
Telephone: 602-325-9346
Fax: 602-325-9360
Internet Address: crawford@noao.edu or dcrawford@noao.edu
Related EJASA Articles -
"Stopping Space and Light Pollution", by Larry Klaes and Phil
Karn - September 1989
"When the Light Gets in Your Eyes, You Shouldn't Have to Drive
to the Country", by James Smith and Ken Poshedly - February 1991
"Curbing Light Pollution in Ohio", by Robert Bunge - June 1991
"Street Lights: The Real Cost", by Steve and Stephanie Binkley -
August 1991
"The Battle Against Light Pollution in Central Ohio", by Earl W.
Phillips, Jr. - September 1991
"Fade to White: The Loss of the Night Sky", by Robert Bunge -
May 1993
About the Author (by the author) -
I am an avid amateur astronomer as well as a part-time researcher
at Perkins Observatory in Delaware, Ohio. I am the RFI Director at
the "Big Ear" radio telescope at Ohio State University (OSU), where we
have been conducting SETI (Search for ExtraTerrestrial Intelligence)
research for more than two decades [You can read about Big Ear and
its SETI project in the June 1992 EJASA. - Editor]. I am an Astronomy
Teaching Assistant under Dr. Phillip Barnhart at Otterbein College
in Westerville, Ohio, and Chief Observer of Otterbein's Weitkamp
Observatory.
I am also the founder of an amateur astronomy club, the Westerville
Astronomy Interest Group (WAIG), whose members learn about the night
sky, contribute to educating the general public through the sponsorship
of public programs, and perform astrophotography and other classes for
its members.
I have conducted a campaign against light pollution to save the
skies surrounding Perkins Observatory for over the last two years.
This has resulted in the first light pollution regulations ever in
Central Ohio. They have either been written into existing zoning
codes or - currently under consideration - in four different local
governmental districts.
I am the current editor of SIGNALS, the newsletter of the "Big Ear"
radio telescope, which has a global circulation, as well as of THE
CASSIOPEAN, the newsletter of the WAIG. I have contributed articles
to the EJASA as well as various newsletters of the astronomical com-
munity on topics ranging from beginning astronomy to light pollution.
I can be reached by mail at: Earl W. Phillips, Jr., 7893
Thornfield Lane, Columbus, Ohio 43235; or by telephone at (614)
764-0476 from 6 p.m. to 10 p.m. weekdays and from 10 a.m. to 10 p.m.
on weekends; or electronically at ephillip@magnus.ircc.ohio-state.edu.
SIGNALS is the official newsletter of the Ohio State University's
(OSU) radio telescope named "Big Ear". Produced more or less monthly,
it describes the goings on at the radio telescope, current research
updates, and occasionally offers preprints. Big Ear is under the
directorship of Dr. Robert Dixon and has been doing SETI research for
over twenty years. For a one-year subscription, send twenty dollars
($20) to: NAAPO, SIGNALS Subscriptions, care of Otterbein College,
Department Physics/Astronomy, Westerville, Ohio 43081. Mention you
read it in the EJASA!
Earl is the author of the following EJASA articles:
"The Battle Against Light Pollution in Central Ohio" - September 1991
"A History of Ohio's Perkins Observatory" - February 1992
THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC
August 1993 - Vol. 5, No. 1
Copyright (c) 1993 - ASA