Date: Mon, 26 Apr 93 05:00:13 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #485 To: Space Digest Readers Precedence: bulk Space Digest Mon, 26 Apr 93 Volume 16 : Issue 485 Today's Topics: Keeping Spacecraft on after Funding Cuts. Level 5? Magellan Update - 04/23/93 Mars Observer Update - 04/23/93 New planet/Kuiper object found? (3 msgs) Russian Email Contacts. space news from Feb 15 AW&ST (2 msgs) Space Station Redesign, JSC Alternative #4 Space Station Redesign Chief Resigns for Health Reasons Sunrise/ sunset times (2 msgs) Surviving Large Accelerations? Vandalizing the sky Weekly reminder for Frequently Asked Questions list What counntries do space surveillance? Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: Fri, 23 Apr 1993 14:31:30 GMT From: Ed McCreary Subject: Keeping Spacecraft on after Funding Cuts. Newsgroups: alt.sci.planetary,sci.space,sci.astro >>>>> On Fri, 23 Apr 93 09:06:09 BST, nicho@vnet.IBM.COM (Greg Stewart-Nicholls) said: GS> How about transferring control to a non-profit organisation that is GS> able to accept donations to keep craft operational. I seem to remember NASA considering this for some of the Apollo equipment left on the moon, but that they decided against it. Or maybe not... -- Ed McCreary ,__o edm@twisto.compaq.com _-\_<, "If it were not for laughter, there would be no Tao." (*)/'(*) ------------------------------ Date: 23 Apr 93 12:47:59 -0600 From: Bill Higgins-- Beam Jockey Subject: Level 5? Newsgroups: sci.space In article <19930422.121236.246@almaden.ibm.com>, Wingert@vnet.IBM.COM (Bret Wingert) writes: > 3. The Onboard Flight Software project was rated "Level 5" by a NASA team. > This group generates 20-40 KSLOCs of verified code per year for NASA. Will someone tell an ignorant physicist where the term "Level 5" comes from? It sounds like the RISKS Digest equivalent of Large, Extra Large, Jumbo... Or maybe it's like "Defcon 5..." I gather it means that Shuttle software was developed with extreme care to have reliablility and safety, and almost everything else in the computing world is Level 1, or cheesy dime-store software. Not surprising. But who is it that invents this standard, and how come everyone but me seems to be familiar with it? Of course, what Shakespeare | Bill Higgins, Beam Jockey ORIGINALLY wrote was "First thing | Fermi National Accelerator Laboratory we do, let's kill all the EDITORS."| Bitnet: HIGGINS@FNAL.BITNET But for some reason it didn't | Internet: HIGGINS@FNAL.FNAL.GOV survive past the first draft. | SPAN/Hepnet: 43011::HIGGINS -- David D. "Laserdave" Levine (davidl@ssd.intel.com) ------------------------------ Date: 23 Apr 1993 20:33 UT From: Ron Baalke Subject: Magellan Update - 04/23/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary Forwarded from Doug Griffith, Magellan Project Manager MAGELLAN STATUS REPORT April 23, 1993 1. The Magellan spacecraft continues to operate normally, gathering gravity data to plot the density variations of Venus in the mid-latitudes. The solar panel offpoint was returned to zero degrees and spacecraft temperatures dropped 2-3 degrees C. 2. An end-to-end test of the Delayed Aerobraking Data readout process was conducted this week in preparation for the Transition Experiment. There was some difficulty locking up to the data frames, and engineers are presently checking whether the problem was in equipment at the tracking station. 3. Magellan has completed 7277 orbits of Venus and is now 32 days from the end of Cycle 4 and the start of the Transition Experiment. 4. Magellan scientists were participating in the Brown-Vernadsky Microsymposium at Brown University in Providence, RI, this week. This joint meeting of U.S. and Russian Venus researchers has been continuing for many years. 5. A three-day simulation of Transition Experiment aerobraking activities is planned for next week, including Orbit Trim Maneuvers and Starcal (Star calibration) Orbits. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and |_____|/ |_|/ |_____|/ | part vegetable. ------------------------------ Date: 23 Apr 1993 20:36 UT From: Ron Baalke Subject: Mars Observer Update - 04/23/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary Forwarded from the Mars Observer Project MARS OBSERVER STATUS REPORT April 23, 1993 10:00 AM PDT Flight Sequence C8 is active, the Spacecraft subsystems and instrument payload performing well in Array Normal Spin and outer cruise configuration, with uplink and downlink via the High Gain Antenna; uplink at 125 bps, downlink at the 2 K Engineering data rate. As a result of the spacecraft entering Contingency Mode on April 9, all payload instruments were automatically powered off by on-board fault protection software. Gamma Ray Spectrometer Random Access Memory was successfully reloaded on Monday, April 19. To prepare for Magnetometer Calibrations which were rescheduled for execution in Flight Sequence C9 on Tuesday and Wednesday of next week, a reload of Payload Data System Random Access Memory will take place this morning beginning at 10:30 AM. Over this weekend, the Flight Team will send real-time commands to perform Differential One-Way Ranging to obtain additional data for analysis by the Navigation Team. Radio Science Ultra Stable Oscillator testing will take place on Monday . The Flight Sequence C9 uplink will occur on Sunday, April 25, with activation at Midnight, Monday evening April 26. C9 has been modified to include Magnetometer Calibrations which could not be performed in C8 due to Contingency Mode entry on April 9. These Magnetometer instrument calibrations will allow the instrument team to better characterize the spacecraft-generated magnetic field and its effect on their instrument. This information is critical to Martian magnetic field measurements which occur during approach and mapping phases. MAG Cals will require the sequence to command the spacecraft out of Array Normal Spin state and perform slew and roll maneuvers to provide the MAG team data points in varying spacecraft attitudes and orientations. Today, the spacecraft is 22,971,250 km (14,273,673 mi.) from Mars travelling at a velocity of 2.09 kilometers/second (4,677 mph) with respect to Mars. One-way light time is approximately 10 minutes, 38 seconds. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | The aweto from New Zealand /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | is part caterpillar and |_____|/ |_|/ |_____|/ | part vegetable. ------------------------------ Date: 23 Apr 1993 18:44:19 GMT From: Jeff Foust Subject: New planet/Kuiper object found? Newsgroups: sci.space In a recent article jdnicoll@prism.ccs.uwo.ca (James Davis Nicoll) writes: > If the new Kuiper belt object *is* called 'Karla', the next >one should be called 'Smiley'. Unless I'm imaging things, (always a possibility =) 1992 QB1, the Kuiper Belt object discovered last year, is known as Smiley. -- Jeff Foust [49 days!] "You're from outer space." Senior, Planetary Science, Caltech "No, I'm from Iowa. I only work in jafoust@cco.caltech.edu outer space." jeff@scn1.jpl.nasa.gov -- from Star Trek IV: The Voyage Home ------------------------------ Date: 23 Apr 93 13:02:46 From: Steinn Sigurdsson Subject: New planet/Kuiper object found? Newsgroups: sci.space In article <1r9de3INNjkv@gap.caltech.edu> jafoust@cco.caltech.edu (Jeff Foust) writes: In a recent article jdnicoll@prism.ccs.uwo.ca (James Davis Nicoll) writes: > If the new Kuiper belt object *is* called 'Karla', the next >one should be called 'Smiley'. Unless I'm imaging things, (always a possibility =) 1992 QB1, the Kuiper Belt object discovered last year, is known as Smiley. As it happens the _second_ one is Karla. The first one was Smiley. All subject to the vagaries of the IAU of course, but I think they might let this one slide... * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * "The worst thing you can say to a true revolutionary is that his * * revolution is unnecessary, that the problems can be corrected without * * radical change. Telling people that paradise can be attained without * * revolution is treason of the vilest kind." -- H.S. 1993 * Just had to try out my new .sig# on this forum ;-) ------------------------------ Date: Fri, 23 Apr 1993 20:42:45 GMT From: James Davis Nicoll Subject: New planet/Kuiper object found? Newsgroups: sci.space In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >In article <1r9de3INNjkv@gap.caltech.edu> jafoust@cco.caltech.edu (Jeff Foust) writes: > > In a recent article jdnicoll@prism.ccs.uwo.ca (James Davis Nicoll) writes: > > If the new Kuiper belt object *is* called 'Karla', the next > >one should be called 'Smiley'. > > Unless I'm imaging things, (always a possibility =) 1992 QB1, the Kuiper Belt > object discovered last year, is known as Smiley. > >As it happens the _second_ one is Karla. The first one was >Smiley. All subject to the vagaries of the IAU of course, >but I think they might let this one slide... Gee, I feel so ignorant now... Research, then post. James Nicoll ------------------------------ Date: Fri, 23 Apr 1993 18:58:50 GMT From: kjenks@gothamcity.jsc.nasa.gov Subject: Russian Email Contacts. Newsgroups: sci.space I am coordinating the Space Shuttle Program Office's e-mail traffic to NPO Energia for our on-going Joint Missions. I have several e-mail addresses for NPO Energia folks, but I won't post them on the 'Net for obvious reasons. If you need to know, give me a yell. -- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office kjenks@gothamcity.jsc.nasa.gov (713) 483-4368 "The earth is the cradle of humanity, but mankind will not stay in the cradle forever." -- Konstantin Tsiolkvosky ------------------------------ Date: Fri, 23 Apr 1993 20:16:24 GMT From: "George F. Krumins" Subject: space news from Feb 15 AW&ST Newsgroups: sci.space jbreed@doink.b23b.ingr.com (James B. Reed) writes: >In article , henry@zoo.toronto.edu (Henry Spencer) writes: >|> [Pluto's] atmosphere will start to freeze out around 2010, and after about >|> 2005 increasing areas of both Pluto and Charon will be in permanent >|> shadow that will make imaging and geochemical mapping impossible. It's my understanding that the freezing will start to occur because of the growing distance of Pluto and Charon from the Sun, due to it's elliptical orbit. It is not due to shadowing effects. >Where does the shadow come from? There's nothing close enough to block >sunlight from hitting them. I wouldn't expect there to be anything block >our view of them either. What am I missing? Pluto can shadow Charon, and vice-versa. George Krumins -- -------------------------------------------------------------------------------- | George Krumins | | gfk39017@uxa.cso.uiuc.edu | | Pufferfish Observatory | ------------------------------ Date: Fri, 23 Apr 1993 20:50:34 GMT From: Henry Spencer Subject: space news from Feb 15 AW&ST Newsgroups: sci.space In article <1993Apr23.155313.4220@dazixco.ingr.com> jbreed@ingr.com writes: >|> [Pluto's] atmosphere will start to freeze out around 2010, and after about >|> 2005 increasing areas of both Pluto and Charon will be in permanent >|> shadow that will make imaging and geochemical mapping impossible. > >Where does the shadow come from? There's nothing close enough to block >sunlight from hitting them. I wouldn't expect there to be anything block >our view of them either. What am I missing? You're assuming that their normal rotation carries all areas of the surface into sunlight. Not so. Even on Earth, each pole gets several weeks without sunlight in mid-winter. Pluto and Charon have much more extreme axial tilt and a much longer orbit. Pluto's north pole, for example, gets over a century of darkness followed by over a century of perpetual light. At the moment, we're in luck -- Pluto and Charon are just past their equinox, when the Sun was just on the horizon at both poles (of each). If we get probes there soon, only the immediate vicinity of one pole (on each) will be in long-term shadow. This will get steadily worse the longer we wait. -- All work is one man's work. | Henry Spencer @ U of Toronto Zoology - Kipling | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Fri, 23 Apr 1993 18:47:32 GMT From: kjenks@gothamcity.jsc.nasa.gov Subject: Space Station Redesign, JSC Alternative #4 Newsgroups: sci.space I have 19 (2 MB worth!) uuencode'd GIF images contain charts outlining one of the many alternative Space Station designs being considered in Crystal City. Mr. Mark Holderman works down the hall from me, and can be reached for comment at (713) 483-1317, or via e-mail at mholderm@jscprofs.nasa.gov. Mark proposed this design, which he calls "Geode" ("rough on the outside, but a gem on the inside") or the "ET Strongback with integrated hab modules and centrifuge." As you can see from file geodeA.gif, it uses a Space Shuttle External Tank (ET) in place of much of the truss which is currently part of Space Station Freedom. The white track on the outside of the ET is used by the Station Remonte Manipulator System (SRMS) and by the Reaction Control System (RCS) pod. This allows the RCS pod to move along the track so that thrusting can occur near the center of gravity (CG) of the Station as the mass properties of the Station change during assembly. The inline module design allows the Shuttle to dock more easily because it can approach closer to the Station's CG and at a structurally strong part of the Station. In the current SSF design, docking forces are limited to 400 pounds, which seriously constrains the design of the docking system. The ET would have a hatch installed pre-flight, with little additional launch mass. We've always had the ability to put an ET into orbit (contrary to some rumors which have circulated here), but we've never had a reason to do it, while we have had some good reasons not to (performance penalties, control, debris generation, and eventual de-orbit and impact footprint). Once on-orbit, we would vent the residual H2. The ET insulation (SOFI) either a) erodes on-orbit from impact with atomic Oxygen, or b) stays where it is, and we deploy a Kevlar sheath around it to protect it and keep it from contaminating the local space environment. Option b) has the advantage of providing further micrometeor protection. The ET is incredibly strong (remember, it supports the whole stack during launch), and could serve as the nucleus for a much more ambitious design as budget permits. The white module at the end of ET contains a set of Control Moment Gyros to be used for attitude control, while the RCS will be used for gyro desaturation. The module also contains a de-orbit system which can be used at the end of the Station's life to perform a controlled de-orbit (so we don't kill any more kangaroos, like we did with Skylab). The centrifuge, which has the same volume as a hab module, could be used for long-term studies of the effects of lunar or martian gravity on humans. The centrifuge will be used as a momentum storage device for the whole attitude control system. The centrifuge is mounted on one of the modules, opposite the ET and the solar panels. This design uses most of the existing SSF designs for electrical, data and communication systems, getting leverage from the SSF work done to date. Mark proposed this design at Joe Shea's committee in Crystal City, and he reports that he was warmly received. However, the rumors I hear say that a design based on a wingless Space Shuttle Orbiter seems more likely. Please note that this text is my interpretation of Mark's design; you should see his notes in the GIF files. Instead of posting a 2 MB file to sci.space, I tried to post these for anon-FTP in ames.arc.nasa.gov, but it was out of storage space. I'll let you all know when I get that done. -- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office kjenks@gothamcity.jsc.nasa.gov (713) 483-4368 "...Development of the space station is as inevitable as the rising of the sun." -- Wernher von Braun ------------------------------ Date: 23 Apr 1993 16:53 EST From: "David B. Mckissock" Subject: Space Station Redesign Chief Resigns for Health Reasons Newsgroups: sci.space In article , xrcjd@mudpuppy.gsfc.nasa.gov (Charles J. Divine) writes... >Writer Kathy Sawyer reported in today's Washington Post that Joseph Shea, the >head of the space station redesign has resigned for health reasons. > >Shea was hospitalized shortly after his selection in February. He returned >yesterday to lead the formal presentation to the independent White House panel. >Shea's presentation was rambling and almost inaudible. I missed the presentations given in the morning session (when Shea gave his "rambling and almost inaudible" presentation), but I did attend the afternoon session. The meeting was in a small conference room. The speaker was wired with a mike, and there were microphones on the table for the panel members to use. Peons (like me) sat in a foyer outside the conference room, and watched the presentations on closed circuit TV. In general, the sound system was fair to poor, and some of the other speakers (like the committee member from the Italian Space Agency) also were "almost inaudible." Shea didn't "lead the formal presentation," in the sense of running or guiding the presentation. He didn't even attend the afternoon session. Vest ran the show (President of MIT, the chair of the advisory panel). > >Shea's deputy, former astronaut Bryan O'Connor, will take over the effort. Note that O'Connor has been running the day-to-day operations of the of the redesign team since Shea got sick (which was immediately after the panel was formed). ------------------------------ Date: 23 Apr 93 08:10:07 GMT From: Theo Wawers Subject: Sunrise/ sunset times Newsgroups: sci.space There is a nice little tool in Lucid emacs. It's called "calendar". On request it shows for given longitude/latitude coordinates times for sunset and sunrise. The code is written in lisp. I don't know if you like the idea that an editor is the right program to calculate these things. Theo W. Theo Wawers LAHMEYER INTERNATIONAL GMBH email : wawers@sunny.lif.de Lyonerstr. 22 phone : +49 69 66 77 639 D-6000 Frankfurt/Main fax : +49 69 66 77 571 Germany ------------------------------ Date: Fri, 23 Apr 93 16:15:23 GMT From: "Daniel A. Asimov" Subject: Sunrise/ sunset times Newsgroups: sci.misc,sci.math,sci.space In article <1993Apr21.141824.23536@cbis.ece.drexel.edu> jpw@cbis.ece.drexel.edu (Joseph Wetstein) writes: > >Hello. I am looking for a program (or algorithm) that can be used >to compute sunrise and sunset times. > >Joe Wetstein There is a wonderful book by Jean Meeus called "Astronomical Algorithms," (1991) which I am fairly sure contains an algorithm for sunrise and sunset times. Dan Asimov Mail Stop T045-1 NASA Ames Research Center Moffett Field, CA 94035-1000 asimov@nas.nasa.gov (415) 604-4799 ------------------------------ Date: Fri, 23 Apr 1993 07:26:42 GMT From: Lan Pham Subject: Surviving Large Accelerations? Newsgroups: sci.space Amruth Laxman writes: > Hi, > I was reading through "The Spaceflight Handbook" and somewhere in > there the author discusses solar sails and the forces acting on them > when and if they try to gain an initial acceleration by passing close to > the sun in a hyperbolic orbit. The magnitude of such accelerations he > estimated to be on the order of 700g. He also says that this is may not > be a big problem for manned craft because humans (and this was published > in 1986) have already withstood accelerations of 45g. All this is very > long-winded but here's my question finally - Are 45g accelerations in > fact humanly tolerable? - with the aid of any mechanical devices of > course. If these are possible, what is used to absorb the acceleration? > Can this be extended to larger accelerations? are you sure 45g is the right number? as far as i know, pilots are blackout in dives that exceed 8g - 9g. 45g seems to be out of human tolerance. would anybody clarify this please. lan > > Thanks is advance... > -Amruth Laxman > ------------------------------ Date: 23 Apr 93 12:55:06 From: Steinn Sigurdsson Subject: Vandalizing the sky Newsgroups: sci.space In article flb@flb.optiplan.fi ("F.Baube[tm]") writes: From: "Phil G. Fraering" > Finally: this isn't the Bronze Age, [..] > please try to remember that there are more human activities than > those practiced by the Warrior Caste, the Farming Caste, and the > Priesthood. Right, the Profiting Caste is blessed by God, and may freely blare its presence in the evening twilight .. The Priesthood has never quite forgiven the merchants (aka Profiting Caste [sic]) for their rise to power, has it? ;-) * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * Ya know... you penguin types offend me. ... * * My Gosh... Life is offensive!! * * Offensensitivity. - BB 1984 * ------------------------------ Date: 23 Apr 1993 13:25:49 -0400 From: Jon Leech Subject: Weekly reminder for Frequently Asked Questions list Newsgroups: sci.space,sci.astro,sci.space.shuttle This notice will be posted weekly in sci.space, sci.astro, and sci.space.shuttle. The Frequently Asked Questions (FAQ) list for sci.space and sci.astro is posted approximately monthly. It also covers many questions that come up on sci.space.shuttle (for shuttle launch dates, see below). The FAQ is posted with a long expiration date, so a copy may be in your news spool directory (look at old articles in sci.space). If not, here are two ways to get a copy without waiting for the next posting: (1) If your machine is on the Internet, it can be obtained by anonymous FTP from the SPACE archive at ames.arc.nasa.gov (128.102.18.3) in directory pub/SPACE/FAQ. (2) Otherwise, send email to 'archive-server@ames.arc.nasa.gov' containing the single line: help The archive server will return directions on how to use it. To get an index of files in the FAQ directory, send email containing the lines: send space FAQ/Index send space FAQ/faq1 Use these files as a guide to which other files to retrieve to answer your questions. Shuttle launch dates are posted by Ken Hollis periodically in sci.space.shuttle. A copy of his manifest is now available in the Ames archive in pub/SPACE/FAQ/manifest and may be requested from the email archive-server with 'send space FAQ/manifest'. Please get this document instead of posting requests for information on launches and landings. Do not post followups to this article; respond to the author. ------------------------------ Date: 23 Apr 93 12:17:25 PST From: thomsonal@cpva.saic.com Subject: What counntries do space surveillance? Newsgroups: sci.space Ethnocentric USian that I am, I've assumed that we and the xUSSR were the only countries with significant capabilities to track non-cooperative objects in low Earth orbit. Grazing in a couple of databases recently, I found that Japan has some optical capabilities along this line, and also uses a radar designed for other purposes for orbital debris surveys (it isn't clear whether the radar can determine orbital elements for the objects it detects). Abstracts of the articles are appended. This leads to the more general question: do yet other people than the US, Russia, and Japan do space surveillance, and if so, how and why? Allen Thomson SAIC McLean, VA, USA ----------------------------------------------------------------------- ABSTRACTS Optical tracking of the experimental geodetic satellite (EGS) TAKABE, MASAO; ITABE, TOSHIKAZU; ARUGA, TADASHI Radio Research Laboratory, Review (ISSN 0033-801X), vol. 34, March 1988, p. 23-34. In Japanese, with abstract in English. This paper reports the optical tracking results of EGS (experimental geodetic satellite) which was launched on August 13, 1986, by NASDA. The EGS optical tracking experiment process and an outline of the Radio Research Laboratory (RRL) optical ground <---- station are discussed. A star tracking technique for optical equipment calibration and satellite tracking technique for orbit prediction improvement are also described. The accuracy of EGS tracking data obtained by RRL at the request of NASDA is also discussed. In addition, it is briefly demonstrated that the position of the Japanese amateur satellite (JAS-1) which was launched with the EGS, was accurately determined by means of a <---- satellite tracking video. It is clear from this experiment that <---- optical observation data (i.e., satellite direction data) are very <---- useful for satellite orbit determination during initial launch <---- stages. Furthermore, the results confirm the effectivenes of these <---- two satellite optical tracking techniques. <---- MU radar measurements of orbital debris SATO, TORU; KAYAMA, HIDETOSHI; FURUSAWA, AKIRA; KIMURA, IWANE (Kyoto University, Japan) AIAA, NASA, and DOD, Orbital Debris Conference: Technical Issues and Future Directions, Baltimore, MD, Apr. 16-19, 1990. 10 p. RPN: AIAA PAPER 90-1343 Distributions of orbital debris versus height and scattering cross section are determined from a series of observations made with a high- power VHF Doppler radar (MU radar) of Japan. An automated data processing algorithm has been developed to discriminate echoes of orbiting objects from those of undesired signals such as meteor trail echoes or lightning atmospherics. Although the results are preliminary, they showed good agreement with those from NORAD tracking radar <---- observations using a much higher frequency. It is found that the <---- collision frequency of a Space Station of 1 km x 1 km size at an altitude of 500 km with orbiting debris is expected to be as high as once per two years. Monitoring of the MU radar antenna pattern by Satellite Ohzora (EXOS-C) SATO, T.; INOOKA, Y.; FUKAO, S. (Kyoto Univ., Japan); KATO, S. Kyoto Univ., Uji (Japan). Radio Atmospheric Science Center. In International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Vol. 20 5 p Publication Date: Jun. 1986 As the first attempt among MST (mesosphere stratosphere troposphere) type radars, the MU (middle and upper atmosphere) radar features an active phased array system. Unlike the conventional large VHF radars, in which output power of a large vacuum tube is distributed to individual antenna elements, each of 475 solid state power amplifier feeds each antenna element. This system configuration enables very fast beam steering as well as various flexible operations by dividing the antenna into independent subarrays, because phase shift and signal division/combination are performed at a low signal level using electronic devices under control of a computer network. The antenna beam can be switched within 10 microsec to any direction within the zenith angle of 30 deg. Since a precise phase alignment of each element is crucial to realize the excellent performance of this system, careful calibration of the output phase of each power amplifier and antenna element was carried out. Among various aircraft which may be used for this purpose artificial satellites have an advantage of being able to make a long term monitoring with the same system. An antenna pattern monitoring system for the MU radar was developed using the scientific satellite OHZORA (EXOS-C). A receiver named MUM (MU radar antenna Monitor) on board the satellite measures a CW signal of 100 to 400 watts transmitted from the MU radar. The principle of the measurement and results are discussed. Equatorial radar system FUKAO, SHOICHIRO; TSUDA, TOSHITAKA; SATO, TORU; KATO, SUSUMU (Kyoto University, Uji, Japan) (COSPAR, IAGA, SCOSTEP, et al., Plenary Meeting, 27th, Workshops and Symposium on the Earth's Middle Atmosphere, Espoo, Finland, July 18-29, 1988) Advances in Space Research (ISSN 0273-1177), vol. 10, no. 10, 1990, p. 151-154. A large clear air radar with the sensitivity of an incoherent scatter radar for observing the whole equatorial atmosphere up to 1000 km altitude is now being designed in Japan. The radar will be built in Pontianak, West Kalimantan, Indonesia (0.03 deg N, 109.29 deg E). The system is a 47-MHz monostatic Doppler radar with an active phased array configuration similar to that of the MU radar in Japan, which has been in successful operation since 1983. It will have a PA product of about 3 x 10 to the 9th W sq m (P = average transmitter power, A = effective antenna aperture) with a sensitivity of approximately 10 times that of the MU radar. This system configuration enables pulse-to-pulse beam steering within 20 deg from the zenith. As is the case of the MU radar, a variety of operations will be made feasible under the supervision of the radar controller. A brief description of the system configuration is presented. ------------------------------ End of Space Digest Volume 16 : Issue 485 ------------------------------