AMSAT-NAAMSAT News Service

April 1, 2001

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Phase 3D/AO-40 Update

The month of April begins with the following AO-40 news from AMSAT-DL:

The last magnetorqueing session (finished March 20th), reduced the spin rate to 1.8 rpm, the planned final value. The rate of spin reduction was about -0.7 rpm/perigee (at times as much as -1 rpm). Overall, the rate of spin reduction was more effective than expected, getting us from 17.6 rpm down to 1.8 rpm in 21 perigees.

Attitude is still being measured, but gave some confusing results. Without magnetorqueing we observed an attitude change of about 5 degrees per day, although calculations show the maximum possible change (due to Sun movement and precession) at only 0.85 degrees per day! This much larger apparent rate of change would explain why the satellite showed larger drops in Sun angle than expected and also why the hibernation period was much shorter than predicted.

After some additional WOD analysis it was found that the change in attitude occurred only when AO-40 was in perigee. Effects of drag in perigee were taken into account, but are obviously much higher than anticipated or calculated, perhaps due to recent higher Sun activity. If this would continue without active attitude change, we would run out of Sun lock within 10 days. Therefore, it was decided to spin up the spacecraft to reduce the rapid change in attitude due to drag. This will give us additional breathing space. In addition, preparation to test the arcjet thruster (as soon as accurate attitude is determined) are under way.

AO-40 also stopped sending telemetry recently, as the last data received was from David, 9M2DT. Because of the recent very high solar activity, the AO-40 team at first thought that the IHU-1 had crashed due to an SEU (Single Event Upset) which could not be corrected by the EDAC (Error Detection and Correction) unit. In fact, we noticed that a soft error (which was corrected by the EDAC system) had occurred. After closer examination by James Miller, G3RUH, it was found the IHU-1 computer had not crashed; it was stuck in a navigation routine loop.

This routine takes MA (Z) as an argument and returns radius and true anomaly of the orbit. Because of the current orbit, the Keplerian element update for the IHU software resulted in a routine failure. Thus, the flight computer was cycling endlessly in a loop.

After discussion with the AO-40 Project leader Dr. Karl Meinzer, DJ4ZC, it was proposed to minimize the pain of reloading the whole software routine by trying a new program, a hot restart procedure that required an 82 byte uploaded. During orbit 191, command station operator Stacey Mills, W4SM, had access to the spacecraft and sent the necessary commands. He was quickly rewarded with telemetry! W4SM also uploaded a software patch, so that the telemetry would not freeze during the next perigee at MA=1. Congratulations to James, Karl and Stacey and the whole command team for a superb job -- well done!

73,
Peter, DB2OS
President AMSAT-DL

(end)

The latest ALON/ALAT estimated value for AO-40 is 172 / 0.

[ANS thanks AMSAT-DL for this information]

KC7NHZ Active from ISS

The ARRL is reporting that Expedition 2 crew member Susan Helms, KC7NHZ, had barely settled in aboard the International Space Station when she apparently felt the urge to do a little hamming!

Sam Danner, N3MPE, of Smithsburg, Maryland, had a scanner set to an ISS 2-meter downlink frequency on the off chance he might hear something -- and he did. Danner then ran out to his car, equipped with a VHF radio programmed with ISS frequencies, and made contact with NA1SS. "It was fantastic!" Danner said. Gordon Williams, VK6IU, also reported hearing Helms calling CQ when the orbiter was over western Australia recently.

The ISS crew will be busy with upcoming school contacts. The Vicksburg, Mississippi High School is scheduled for a direct contact during the week of April 4th, followed by the Woodford County Middle School, the Admiral Moorer Middle School and the Parkway Central High School, all scheduled during the month of April.

NASA has released a photograph of Sergej Krikalev, U5MIR, in the area where the ISS 2-meter radio is located. The corner of the packet module is also visible in the photograph. See the NASA release at http://garc9.gsfc.nasa.gov/~ariss/u5mir-is.jpg

[ANS thanks the ARISS group and the ARRL for this information]

NASA Names Future ISS Crews

As the Expedition 2 crew settles aboard the International Space Station, American crew members for future space station missions have been named by NASA. The astronauts will join a corps of expedition astronauts and cosmonauts previously named to the first four crews. Russian members of these new expedition crews will be formally announced in the near future.

The Expedition 5 crew will consist of astronaut Peggy Whitson and two Russian cosmonauts, one of whom will be the mission commander. Navy Captain Kenneth Bowersox will command the Expedition 6 crew that includes astronaut Donald Thomas and a Russian cosmonaut. American astronaut Ed Lu along with a Russian commander and flight engineer make up the Expedition 7 crew. Lu will make his third trip to space, having flown on STS-84 in 1997 and STS-106 in 2000. Astronaut Michael Foale, serving as commander of Expedition 8, will have Colonel William McArthur and a Russian cosmonaut as flight engineers. Foale has flown in space five times, including a long-duration stay aboard Mir in 1997.

A complete list of all astronauts and cosmonauts in ISS training, along with their biographical data, can be found at http://www.jsc.nasa.gov/Bios/

[ANS thanks NASA for this information]

ISS Special Event Planned

The ARISS team has received permission from the 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, 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.

Specific operating times and modes will be announced later. Check to the ARISS web page for the latest details: http://ariss.gsfc.nasa.gov/

[ANS thanks ARISS team member Will Marchant, KC6ROL, for this information]

AMSAT-UK Second Call for Papers

The 16th AMSAT-UK Colloquium will be held at Surrey University, Guildford, Surrey, United Kingdom, July 27-29, 2001. This is the second call for papers.

AMSAT-UK invites speakers to submit papers about amateur radio space and associated activities, for this event and for the Proceedings document which will be published at the same time.

This year, anticipating some sort of availability of AO-40, we are particularly interested to have papers related to this project.

Offers of papers should be submitted as soon as possible; the date for full documents to be received is mid-June 2001.

Submissions should be sent via the following routes:

Internet e-mail: g3rwl@amsat.org

Terrestrial mail:

    R W Limebear, G3RWL
    60 Willow Road
    Enfield EN1 3NQ
    United Kingdom

AMSAT-UK also invites anyone with requests for program topics to submit them as soon as possible to G3RWL. Additionally, AMSAT-UK will be running sessions specifically for beginners to amateur radio satellite operating and volunteers are requested to speak to these sessions.

[ANS thanks Richard Limebear, G3RWL, Colloquium Organizer, or this information.]

ANS in Brief

ANS news in brief this week includes the following:

Weekly Satellite Report

Link to the weekly report on satellite ...

All Satellites
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 ans-editor@amsat.org, or to ANS Editor Dan James, NN0DJ, at nn0dj@amsat.org.

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This week's AMSAT News Service bulletins were edited by AMSAT  News Service editor Dan James, NN0DJ.

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