Longer Eclipse Periods Affecting AO-51

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Amsat Oscar AO-51AO-51 Command Stations report that the seven year old spacecraft is now shutting down its transmitter after losing sunlight on its solar panels during eclipse periods. Two of the six battery cells are now dead. Since July 31, 2010 AO-51 has maintained continuous and stable operations due to careful tuning of its power settings.

The AO-51 Operations Team reported on November 25 that the on-board computer (IHU) crashed between 1815 and 1945Z due to low voltage. This happened after a few days of intermittent and unpredictable operation.

AO-51 Control Operators Mark Hammond, N8MH and Drew Glasbrenner, KO4MA reset the satellite and started the repeater back up around ~2030Z. Satellite operation was set to the following:

Uplink: 145.880, no PL tone required
Downlink: 435.150 at about 300 milliwatts

Satellite EclipseDrew reported that telemetry data showed the battery voltage was low, around 4.9v, with cell 1 less than 1 volt. The impending third cell failure will likely end continuing operations, particularly if it fails shorted as the others have. At present there remains little margin as the operations team has observed the transmitters cutting off around 4.7 to 4.6 volts prior to the last reset, in eclipse.

Please submit your AO-51 reports to the OSCAR Status Web Page: http://oscar.dcarr.org. The command stations monitor this for changes in the operation. While worldwide participation is good, more reports from US operators are appreciated.

Eclipse periods, which are expected to reach 30 minutes by the end of 2011, are causing AO-51 to shut itself OFF due to low voltage.

Please support AMSAT-NA and the other AMSAT groups around the world, and help us get new satellites into orbit. Projects like Fox, FunCube, P3E, and Kiwisat need your financial support to keep our amateur satellite fleet flying.

You can keep up with the latest AO-51 Command Team news at:
http://www.amsat.org/amsat-new/echo/CTNews.php

Source: Amsat NA

Last chances to hear ARISSat-1

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Last chances to hear ARISSat-1 are rapidly approaching.

ARISSat-1A reminder that if you have been putting off working through the ARISSat-1 repeater, receiving SSTV pictures, or submitting telemetry, the next few weeks will be your last opportunity to be a part of this satellite’s history. Since deployment in August, ARISSat-1 has descended about 60 km, and is currently losing more than 1.5 km per day. The rapid rate is partially the result of the recent solar activity on the atmosphere, significantly increasing the drag. The predictions by several individuals and groups are all converging toward a reentry in January or February, 2012. Heating will become significant before then. Remember, good telemetry in this period provides invaluable information to the engineering team, to be used in future projects.

The orbit period changes about 30 seconds per day, and that will increase steadily. Be certain to update your tracking program Keps from Space-Track or CelesTrak before each pass. They issue revised versions 3-5 times daily. As the descent continues, this will become even more critical to copying the telemetry beacon, especially unattended.

73s, Alan WA4SCA

This picture is the decay rate calculated by DK3WN

ARISSat Decay by DK3WN

20 meter EME net

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2m EME AntennasPlease remember that the 20 meter EME net meets on saturday and sunday on 14.345 Mhz at 1500 UTC during the winter in the northern hemisphere. I start with the antenna on europe.

We need the participation of all possible members of the EME gang to exchange ideas.
Among us we have a vast wealth of knowledge. Individually we are limited.

Please join us on saturday and sunday and share some of your brilliant ideas with those of us who have struggled to become or are learning to become proficient at our passion.

The newcomer may be surprized at what he may have to share and the old timers already know the vast amount of experience they have.

Please! Let’s share that knowledge with each other.

Steve Gross N4PZ

AO-51 IHU Crash

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Satellite IHUAMSAT-NA VP Operations Drew Glasbrenner KO4MA reports on Friday’s IHU crash on the Amateur Radio satellite AO-51. Sometime between 1815 and 1945Z November 25, AO-51′s IHU crashed. This happened after a few days of intermittent and unpredictable operation.

Mark N8MH and I reset the satellite and started the repeater back up around ~2030Z, and lowered the output power to about 300 milliwatts. Battery voltage was low, around 4.9v, with cell 1 less than 1 volt. This is very troublesome, as the impending third cell failure will likely end our continuing operations, particularly if it fails shorted as the others have. We’ve also observed the transmitters cutting off around 4.7 to 4.6 volts prior to the last reset, in eclipse.

We’ll do what we can, but her days are short. Let me ask once again for more reports, especially from the US operators, to the Live Satellite Status webpage. The command stations monitor this for changes in the operation of AO-51, and while worldwide participation is good, few US operators post to it.

Update Nov 27, 2011:

AO-51 still off-air. Satellite is not responding to commands, we suspect that the 3rd cell has failed short, therefor insufficient voltage for the transmitter.

Proposal to NASA for Fox-1 Launch

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NASA LogoAMSAT submitted a proposal to NASA for their CubeSat Launch Initiative, also known as the ‘Educational Launch of NanoSat’ (ELaNa) program. NASA selects projects that they deem to have merit in support of their strategic and educational goals. Projects that are selected will be able to enter into a collaboration agreement where NASA will cover the integration and launch costs of the satellite.

AMSAT, working with ARRL, highlighted the educational merit of the project including the incorporation of Fox-1 into the ARRL Teacher Institute seminars. ARRL also provided a letter of support for the project that was a key component of our proposal.

The Clay Center for Science and Technology at the Dexter and Southfield schools in Brookline MA, also provided a letter of support that was an important part of our proposal. The Clay Center noted that they use AMSAT satellites such as ARISSat-1 in their educational activities for K-12 students and that they look forward to making use of Fox-1. The completed proposal, at 159 total pages, required a significant effort that was all done by volunteers. NASA will select from all of the submissions and announce the winning projects by January 30, 2012.

Tony Monteiro, AA2TX
AMSAT Vice-President of Engineering

Lecture Cubesats Veron Breda

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Veron LogoHot off the press – Lecture Cubesats Veron Breda (R07)

Wouter Weggelaar (PA3WEG) will give a lecture on cubsats including Delfi-C3, Delfi-n3Xt and FUNcube on March 6, 2012. The lecture will take place during one of the club nights of Veron Breda (R07). For details, see the website from Veron Breda.

A CubeSat is a type of miniaturized satellite for space research that usually has a volume of exactly one liter (10 cm cube), has a mass of no more than 1.33 kilograms, and typically uses commercial off-the-shelf electronics components. Beginning in 1999, California Polytechnic State University (Cal Poly) and Stanford University developed the CubeSat specifications to help P-Pod Launcheruniversities worldwide to perform space science and exploration. Since CubeSats are all 10×10 cm (regardless of length) they can all be launched and deployed using a common deployment system. CubeSats are typically launched and deployed from a mechanism called a Poly-PicoSatellite Orbital Deployer (P-POD), also developed and built by Cal Poly. P-PODs are mounted to a launch vehicle and carry CubeSats into orbit and deploy them once the proper signal is received from the launch vehicle. P-PODs have deployed over 90% of all CubeSats launched to date (including un-successful launches), and 100% of all CubeSats launched since 2006.