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April continues with recovery efforts concerning AO-40. The AMSAT-DL web page is reporting the following:
Plans have changed recently. We have found that there is a significant effect at perigee caused (we believe) by the satellite encountering an atmospheric induced change. This causes ALON to decrease by about 3 degrees each perigee (when the spin rate is at 2 rpm). In addition, ALON already reduces 0.7 degrees each perigee due to precession of the orbital plane -- so we were seeing nearly a 4-degree change each perigee pass, or about 5 degrees each day. Despite eclipses, the magnetorquer is a bit stronger than this effect and we are able to counteract and actually increase ALON by about 1 degree each perigee. Shifting ALON from 170 to 270 (at the 1-degree rate) was clearly going to take a very long time, even given that our assumptions could be extrapolated to different geometry. Meanwhile, perigee height is decreasing steadily due to solar perturbations. Because of these parameters the move from ALON 170 to 270 has been put on hold.
Instead, we are going to change ALON the other direction, taking it down to 90 and then through 0 and hopefully to 270 later in the year. There are a number of benefits of this plan:
During this procedure, AO-40 will go into hibernation again. This is the name we've given to the state where the Sun sensor system cannot see the Sun, so the satellite cannot be magnetorqued by normal means. However, if the atmospheric effect continues to work as it evidently did during the previous hibernation, this period of poor Sun angle will be short lived. Also, at this time there is a possibility that the Sun will be nearly coaxial with the spin axis. The bottom of the spacecraft will be illuminated (not the top) reducing the effect of continuous, direct sunlight on the onboard cameras.
The following is our best estimate of the way things will evolve. The Sun angle will reach a point where the sensor will stop seeing the Sun in early April. Then we wait (perhaps) 4-6 weeks for the Sun angle reach a recovery point. By this time the ALON numbers should favor decent beacon communication. Although the Sun sensor will not give data, the temperature profile will provide Sun angle clues, as can be seen using recorded (historic) telemetry.
|Apr 05||146/0||280/5||-44||72% (lock loss)|
The command team welcomes informed discussion as to why ALON is rapidly decreasing (the attitude vector direction changes clockwise as viewed from the orbit plane). This change only occurs close to perigee. The phenomenon is clearly observed, but is not explained.
Moe, AE4JY, has placed an updated version of his popular AO40Rcv telemetry program. The latest version, 1.10, is available at http://qsl.net/ae4jy/
[ANS thanks AMSAT-DL for this information]
The ARRL is reporting that the call for reports of apparent unlicensed operation on 10 and 12 meters has been "overwhelming," according to Brennan Price, N4QX, administrator of the ARRL Monitoring System.
Problems with interference to several satellite uplinks has been well documented in ANS reports. The survey last October was initiated in response to an increasing number of complaints from the amateur community.
Price said that more than 400 separate reports, nearly all from United States amateurs, detailed more than 1000 separate instances of apparent unlicensed operation. An analysis suggests that nearly half of the transmissions originated in the United States. Of the remaining reports, most appeared to document transmissions originating in Latin America. AO-27 and UO-14 satellite operators are very aware of similar transmissions and the problems they cause.
The ARRL has shared its data with the FCC.
Price points out that before the Commission can take any action, an offending transmission must be documented and its source found. Price said the FCC relies on the amateur service to be self-policing and has indicated that it is most likely to act in suspected unlicensed operator situations when amateurs themselves document the cases. Price said active use of the bands by licensees is the best way to discourage unlicensed operation. "It is not easy or quick work, but it has been successfully done in the past," he said.
[ANS thanks the ARRL for this information]
As announced last week, the ARISS team has received permission from ISS controllers to declare April 12, 2001 as a special event day for Amateur Radio aboard the International Space Station!
The ARISS team is requesting the crew (on a voluntary basis), to attempt as may general ham radio contacts as possible over the major landmasses of the Earth to help celebrate Cosmonautics Day.
This year the April 12th Cosmonautics Day holiday celebrates the 40th anniversary of the first human spaceflight by Yuri Gagarin, UA1LO, the 30th anniversary of the first space station (Salyut-1), and the 20th anniversary of the first launch of the first reusable space vehicle, the American space shuttle.
With the help of the ARISS team orbital mechanics expert Gil, WA5NOM, the ARISS team has prepared a list of suggested passes for the April 12th event. Actual pass times may change due to the unusually high level of solar activity.
|Western U.S.||07:53 - 08:13 UTC|
|Central Russia and Japan||13:43 - 14:13 UTC|
|Western Russia||18:29 - 18:49 UTC|
|Australia||18:58 - 19:18 UTC|
|Europe||19:59 - 20:19 UTC|
Check to the ARISS web page for the latest details. http://ariss.gsfc.nasa.gov/
The following frequencies have been announced for ARISS general QSOs:
|voice and packet downlink||145.80 (worldwide)|
|voice uplink||144.49 Regions 2 and 3|
|voice uplink||145.20 Region 1|
|packet uplink||145.99 (worldwide)|
The QSL routes for W/VE stations working NA1SS aboard the International Space Station:
|U.S stations:||Margie Bourgoin KB1DCO
Attn: ARISS Expedition-1 (or 2) QSL
ARRL, 225 Main Street
Newington, Connecticut 06111
|Canadian stations:||Radio Amateurs of Canada
Attn: ARISS Expedition-1 (or 2) QSL
720 Belfast Road, Suite 217
Ottawa, Ontario K1G 0Z5
A self-addressed, stamped envelope is required to get a QSL in return. The ARISS international group has not yet finalized a QSL card design, so it could be a few months before cards become available.
As this ANS bulletin set is broadcast, the packet system aboard ISS has been activated! Look for more information in the next edition of ANS and check the AMSAT-NA bulletin board for the latest data.
[ANS thanks the ARISS team and the ARRL for this information]
The Maryland-DC area AMSAT Meeting and Space Seminar was held Sunday, April 1, 2001 in the Visitor Center auditorium of the NASA Goddard Space Flight Center in Greenbelt, Maryland. The event has proven to be both a popular and successful annual affair.
Rick Hambly, W2GPS, gave a fascinating, detailed presentation on AO-40 telemetry. Dick Daniels, W4PUJ, presented "What happened to AO-40" -- starting with a slideshow of photos from the Phase 3D launch campaign and followed with a detailed review of what is known, suspected and not known about events on-board AO-40.
AMSAT-NA's Frank Bauer, KA3HDO, briefed the crowd on the future plans for ARISS equipment and enhancements, including packet, SSTV and ATV. In a related topic, Will Marchant, KC6ROL, gave an update on current and near-future ARISS operations. On display were examples of ARISS VHF/UHF and HF antennas as well as an ARISS packet controller.
AMSAT-NA President Robin Haighton, VE3FRH, shared some of his views and Barry Baines, WD4ASW, explained his role in the AMSAT field operations organization and talked about the very flexible roles of AMSAT Area Coordinators.
Tom Clark, W3IWI, explained just what is required to get a satellite in orbit as well as other satellite design parameters such as cost, assembly, reliability and complexity.
Bob Bruninga, WB4APR, demonstrated his briefcase-sized automated digital satellite station and spoke about the PCSat project.
Bob Rose, AA3RR, talked about his efforts in building an organization to make amateur radio more accessible to students and young people.
ANS congratulates Pat Kilroy, N8PK, and his countless volunteers who did a polished and professional job of organizing and holding the event.
A photograph of the event (and those who participated) is available at http://simsat.gsfc.nasa.gov/ssamsatdc.html
[ANS thanks Maggie Leber, K3XS, for this information.]
ANS news in brief this week includes the following:
Link to the weekly report on satellite ...
ISS . RS-12 . RS-13 . RS-15 . AO-10 . UO-11 . UO-14 . AO-16 . DO-17 . WO-18 . LO-19 . FO-20 . UO-22 . KO-23 . KO-25 . IO-26 . AO-27 . FO-29 . TO-31 . GO-32 . SO-33 . PO-34 . SO-35 . UO-36 . AO-40 . SO-41 . SO-42
Please send any amateur satellite news or reports to the ANS Editors at firstname.lastname@example.org, or to ANS Editor Dan James, NN0DJ, at email@example.com.
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This week's AMSAT News Service bulletins were edited by AMSAT News Service editor Dan James, NN0DJ.