July 8, 2001
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The ARRL is reporting that AO-40's new orbit should be good for at least the next 20 years. The League based the story on information
from AMSAT-DL President Peter Guelzow, DB2OS. Peter heads the satellite's ground control team. Following maneuvers to shift the
satellite's orbit at perigee, AO-40 perigee now is "oscillating in a safe range between 810 and 1260 km," according to DB2OS.
AO-40's height at apogee of 58,971 km was unchanged by the orbital adjustment. The satellite's transponders remain off as ground
controllers reorient the spacecraft.
Ground controllers were able to change AO-40's orbit through successive cold firings of the onboard
arcjet motor, using only ammonia gas. The move raised AO-40 higher than predicted, and
apparently depleted the spacecraft's ammonia supply. As a result, AO-40 likely will remain in its current orbit.
Stacey Mills, W4SM, of the ground team said it's "quite possible" that an ammonia leak accounted for the unexpected loss of ammonia.
"If we did have a slow leak, it is very fortunate we did not wait any longer to use the remaining fuel," he said.
Mills said that AO-40's old orbital configuration, while stable, was too close for comfort at perigee.
"I sincerely hope that nothing else malfunctions for a long, long time, but this is, after all, rocket science," Mills said. "Nothing
Ground controllers plan to fully test AO-40's momentum wheels prior to any decision to deploy the spacecraft's solar panels. The momentum
wheels provide three-axis control of the spacecraft. If the momentum wheels are not operational, it's unlikely the solar panels will be
Stay tuned to ANS, the official source of AO-40 information.
[ANS thanks the ARRL for this information]
John, KD2BD, has released an updated version of Predict, a popular satellite tracking and orbital prediction application for the Linux
operating system. Predict version 2.1.4 includes the following changes from the previous version:
- An array overflow problem in the Solar Illumination Prediction mode
has been fixed
- Pressing [R] in either the Single or Multi-Tracking mode forces Predict to re-read the orbital database. This will be useful if
the database is updated manually through available Predicts update options while the program is running. This will eliminate the need to
re-start the program under such conditions
- Real-time tracking is no longer attempted for satellites that appear to
have decayed from orbit
- Several new options were added to the 'F' command-line switch. If no
starting or ending date/time is specified, a single line of output corresponding to the current date/time is produced
- Multiple Keplerian element data files may now be used as arguments
for the 'U' command-line switch
- Several network client applications were added or otherwise revised
- The configuration and compilation process has been modified slightly
to reduce confusion during installation
Best of all, Predict is free software!
The program can be found at ftp://ftp.amsat.org/amsat/software/Linux/predict-2.1.4.tar.gz
The Predict homepage is located at http://www.qsl.net/kd2bd/predict.html
[ANS thanks John Magliacane, KD2BD, for this information]
ANS news in brief this week includes the following:
- Could life thrive where the Sun never shines? The answer to this
unorthodox question bears directly on the tantalizing possibility that life exists in the hidden, perpetually dark oceans that are
thought to shroud some of Jupiter's moons, most prominently Europa.
- A space shuttle mission to deliver a key component that will enable astronauts to conduct spacewalks on the Earth-orbiting
International Space Station was the subject of briefings help recently. Designated mission STS-104, Space Shuttle Atlantis is
scheduled for launch no earlier than July 12th. After an extensive
engineering analysis, International Space Station Program managers
gave the green light to proceed with the launch of Atlantis. Currently, the International Space Station is orbiting at an altitude
averaging 240 miles.
- A new robotic explorer, smart enough to know when it's lost or in
trouble and designed to follow the Sun in a whole new way, is ready
to face its first test in the harsh elements of the Canadian Arctic.
The prototype robot, named Hyperion, has the potential to be self-sufficient and will help researchers test a technique called
- It's now under five weeks before the AMSAT-UK Colloquium at the University of Surrey. Details are available at
- An astronaut who exits a spacecraft without a spacesuit will die
very quickly because there is no air to breathe. However, although
space is often regarded as an airless vacuum, it is by no means empty. Spacecraft such as Cluster are built to detect and study the
sparse 'soup' of electrified plasma -- mostly electrons and protons
-- that populates near-Earth space.
- Aboard ISS the Expedition-2 crew continues to test the station's
robotic arm in preparation for its first official task of permanently
installing the airlock onto the Unity module. Expedition-2 Flight Engineers Jim Voss and Susan Helms are conducting additional dress
rehearsals of the airlock installation task. The International Space
Station is orbiting at an altitude averaging 240 miles.
Link to the weekly report on satellite ...
Please send any amateur satellite news or reports to the
ANS Editors at email@example.com,
or to ANS Editor Dan James, NN0DJ, at firstname.lastname@example.org.
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This week's AMSAT News Service bulletins were edited by
AMSAT News Service editor Dan James, NN0DJ.