• ARLS011 AO-40 Now in Long-Term, ''Safe'' Orbit

    From George Avera@1:393/3 to All on Wed Jul 11 22:23:39 2001
    ARLS011 AO-40 Now in Long-Term, "Safe" Orbit

    ZCZC AS11
    QST de W1AW
    Space Bulletin 011 ARLS011
    From ARRL Headquarters
    Newington, CT July 11, 2001
    To all radio amateurs

    ARLS011 AO-40 Now in Long-Term, ''Safe'' Orbit

    AO-40's new orbit should be good for at least the next 20 years,
    according to AMSAT-DL President Peter Guelzow, DB2OS, who heads the
    satellite's ground 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,'' Guelzow said.

    AO-40's height at apogee--58,971 km--was unchanged by the orbital
    adjustment. The satellite's transponders remain off as ground
    controllers reorient the spacecraft. Still in question is whether
    ground controllers will be able to deploy the satellite's solar

    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 some 300 km higher than
    predicted, but it 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
    is guaranteed.''

    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 deployed.

    For more information on AO-40, visit the AMSAT-DL Web site, http://www.amsat-dl.org/ or the AMSAT-NA Web site,
    http://www.amsat.org. AMSAT-DL now offers an AO-40 ''Quick Status''

    --- Aeolus v1.2.2b3 (#96101098)
    * Origin: The ChatterBox, Justin Texas (1:393/3)