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From: [e-mail] (Larry Klaes)
Subject: Electronic Journal of the ASA (EJASA) - April 1993
Message-ID: <[e-mail]>
Keywords: Venus, Venera, Soviet, probes
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                          THE ELECTRONIC JOURNAL OF
                  THE ASTRONOMICAL SOCIETY OF THE ATLANTIC

                       Volume 4, Number 9 - April 1993

                         ###########################

                              TABLE OF CONTENTS

                         ###########################

          * ASA Membership and Article Submission Information

          * The Soviets and Venus, Part 3 - Larry Klaes

                         ###########################

                         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.

        [e-mail]

        ASA BBS: [phone], 300/1200/2400 Baud

        or telephone the Society Recording at [phone] 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:

        [e-mail]
        or - ...!decwrl!verga.enet.dec.com!klaes
        or - [e-mail]
        or - [e-mail]

        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: /pub/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.  This Journal is Copyright (c) 1993
    by the Astronomical Society of the Atlantic, Incorporated.


                             THE SOVIETS AND VENUS
                                     PART 3

                       Copyright (c) 1993 by Larry Klaes

	The author gives permission to any group or individual wishing
	to distribute this article, so long as proper credit is given,
        the author is notified, and the article is reproduced in its 
        entirety.

        To the North Pole!

        On June 2 and 7, 1983, two of the Soviet Union's mighty PROTON 
    rockets lifted off from the Tyuratam Space Center in the Kazakhstan 
    Republic.  Aboard those boosters were a new breed of VENERA probe 
    for the planet Venus. 

        Designated VENERA 15 and 16, the probes were meant not for landing
    yet more spherical craft on the Venerean surface but to radar map the
    planet in detail from orbit.  To accomplish this task, the basic
    VENERA design was modified in numerous areas.  The central bus core
    was made one meter (39.37 inches) longer to carry the two tons of
    propellant required for braking into orbit, double the fuel carried by
    the VENERA 9 and 10 orbiters eight years earlier.  Extra solar panels
    were added on to give the vehicles more power for handling the large
    amounts of data which would be created by the radar imaging.  The
    dish-shaped communications antennae were also made one meter larger 
    to properly transmit this information to Earth. 

        Atop the buses, where landers were usually placed, were installed
    the 1.4 by 6-meter (4.62 by 19.8-foot), 300-kilogram (660-pound)
    POLYUS V side-looking radar antennae.  The radar system, possibly a
    terrain-imaging version of the nuclear-powered satellites used by 
    the Soviets for Earth ocean surveillance, would be able to map Venus'
    surface at a resolution of one to two kilometers (0.62 to 1.2 miles). 

        The Soviet probes' imaging parameters were a vast improvement over
    the United States PIONEER VENUS Orbiter, which could reveal objects 
    no smaller than 75 kilometers (45 miles) in diameter.  And while the
    VENERAs' resolution was comparable to that of similar observations 
    made by the 300-meter (1,000-foot) Arecibo radio telescope on the 
    island of Puerto Rico, the orbiters would be examining the northern
    pole of Venus.  This region was unobtainable by either Arecibo or 
    PIONEER VENUS and appeared to contain a number of potentially 
    interesting geological features worthy of investigation.

        On October 10, 1983, after an interplanetary journey of 330 
    million kilometers (198 million miles) and two mid-course corrections, 
    VENERA 15 fired its braking rockets over Venus to place itself in a 
    polar orbit 1,000 by 65,000 kilometers (600 by 39,000 miles) around 
    the planet, completing one revolution every twenty-four hours.  VENERA 
    16 followed suit four days later.  The twin probes thus became Venus' 
    first polar-circling spacecraft.

        Radar operations began on October 16 for VENERA 15 and October 20 
    for VENERA 16.  For up to sixteen minutes every orbit over the north
    pole, the probes would make a radar sweep of the surface 150 kilometers 
    (ninety miles) wide and nine thousand kilometers (5,400 miles) long.  
    The craft would then head out to the highest part of their orbits over 
    the south pole to recharge their batteries and transmit the data back 
    to two large Soviet antennae on Earth.  Each strip of information took 
    eight hours to process by computer.  By the end of their main missions 
    in July of 1984, the VENERAs had mapped 115 million square kilometers 
    (46 million square miles), thirty percent of the entire planet.

        VENERA 15 and 16 revealed that Venus has a surface geology more
    complex than shown by PIONEER VENUS in the late 1970s.  Numerous hills, 
    mountains, ridges, valleys, and plains spread across the landscape, 
    many of them apparently formed by lava from erupting volcanoes in the 
    last one billion years.  In planetary terms this makes the Venerean 
    surface rather young.  Hundreds of craters were detected as well, the 
    largest of which had to have been created by meteorites (planetoids 
    would be a better term here) at least fourteen kilometers (8.4 miles) 
    across, due to Venus' very dense atmosphere.

        There were some disagreements between U.S. and Soviet scientists
    on the origins of certain surface features.  For example, the probes' 
    owners declared that the 96-kilometer (57.6-mile) wide crater at the 
    summit of 10,800-meter (35,640-foot) high Maxwell Montes, the tallest 
    mountain on the planet, was the result of a meteorite impact.  American 
    scientists, on the other hand, felt the crater was proof that Maxwell 
    was a huge volcano sitting on the northern "continent" of Ishtar Terra.  

        In any event, the U.S. decided to wait on making verdicts about
    Venus until the arrival of their own radar probe, scheduled for later
    in the decade.  Originally named the Venus Orbiting Imaging Radar
    (VOIR), its initial design was scaled back and the craft was redesig-
    nated the Venus Radar Mapper (VRM).  Eventually the machine would be 
    called MAGELLAN, after the Portuguese navigator Ferdinand Magellan 
    (circa 1480-1521).  This vehicle would map the entire planet in even 
    finer detail than the VENERAs.  For the time, however, the Soviet 
    probes maintained that distinction.

        Radar imaging was not the only ability of the VENERAs.  Bolted
    next to the POLYUS V radar antenna were the Omega altimeter and the 
    Fourier infrared spectrometer, the latter for measuring the world's
    temperatures.  The majority of the areas covered registered about
    five hundred degrees Celsius (932 degrees Fahrenheit), but a few
    locations were two hundred degrees hotter, possibly indicating 
    current volcanic activity.  The probes also found that the clouds 
    over the poles were five to eight kilometers (three to 4.8 miles) 
    lower than at the equator.  In contrast, the polar air above sixty 
    kilometers (thirty-six miles) altitude was five to twenty degrees 
    warmer than the equatorial atmosphere at similar heights.

        When the main mapping mission ended in July of 1984, there were 
    plans for at least one of the VENERAs to radar image the surface at 
    more southernly latitudes.  Unfortunately this idea did not come to 
    pass, as the orbiters may not have possessed enough attitude-control
    gas to perform the operation.  

        VENERA 15 and 16 ceased transmission in March of 1985, leaving 
    the Soviet Institute of Radiotechnology and Electronics with six 
    hundred kilometers (360 miles) of radar data tape to sort into an 
    atlas of twenty-seven maps of the northern hemisphere of Venus.