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Phase 3D/AO-40 Update

Discussion in 'Amateur Radio News' started by Guest, Feb 12, 2001.

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  1. Guest

    Guest Guest

    The month of February begins with command stations continuing their on-going recovery efforts of AMSAT OSCAR 40.

    The AMSAT-DL web site is currently featuring the following statement:

    AO-40 is currently like a ship on a sandbank at low-tide and in the fog. In the fog because of the high solar-angle (maximum of 77 degrees) where the onboard sun sensor(s) temporarily cannot see. At low-tide because the increasing solar-angle leads to less illumination (minimum of 23 percent) -- thus less energy is produced. AO-40 is stuck on a sandbank because the satellite cannot be maneuvered out of this situation very easily. The 'de-spinning' software routine may help. This program should work without sun sensor data and will use on-going measurements from the solar panels as an attitude indicator. Intensive work on this software is currently taking place.

    Even if this routine doesn't work immediately, there is no reason to panic. The 'fog and low-tide' orbit will disappear with further seasonal Sun movements around the spacecraft. By April the sensors will see the Sun again and active attitude control can be restarted. After lowering the current spin rate, improving the Sun angle and repositioning AO-40's antennas, all further tests can be done.

    Command stations G3RUH and W4SM have completed a long-term prediction of AO-40's new orbit. Even after last year's accident and the resulting decrease of perigee - AO-40's orbit will be fairly stable through this period.

    ALON/ALAT is currently 248/-7, as last listed on the AMSAT-DL web page.

    The AO-40 element set (number 30) is as follows:

    Satellite: AO-40

    Catalog number: 26609

    Epoch time: 01027.28372779

    Inclination: 5.8370 degrees

    RA of node: 227.6036 degrees

    Eccentricity: 0.8132970

    Arg of perigee: 212.6216 degrees

    Mean anomaly: 48.4646 degrees

    Mean motion: 1.26933309 rev/day

    Decay rate: -7.0e-07 rev/day^2

    Epoch rev: 111

    Checksum: 274
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