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[jamsat-bb:8903] Re: AO-40: more successful ARCJET operations
衛星AO-40までの地表距離を、ケプラー方程式ニュートン近似法による
アルゴリズムを用いて計算してみました。
6月23日に実施された 衛星AO-40のアークジェットの噴射前と噴射後の
近地点/遠地点(Perigee/Apogee)の「地表距離」は、この計算結果によ
ると次のようになりました。
(This analysis)
Before After
Perigee height : 286.0 288.4 ....... +2.4 km
Apogee height : 58967.2 58966.8 ....... -0.4 km
(Peter report)
Before After
Perigee height : 279.754 282.2427 .... +2.5 km
Apogee height : 58971.166 58971.024 .... -0.1 km
http://www.asahi-net.or.jp/~ei7m-wkt/numbr271.htm
http://www.ne.jp/asahi/hamradio/je9pel/a40rangj.zip
AO-40 コマンドチームの DB2OS/Peter Guelzow氏 による amsat-bb へ
の広報の中の数値と比較すると、ほんの少し差違があるものの、その
変移はほぼ同じ結果となりました。
> Date: Sat, 23 Jun 2001 10:08:15 +0000
> From: Peter Guelzow <peter.guelzow@arcormail.de>
> To: amsat-bb@amsat.org, forum@amsat-dl.org
> Subject: AO-40: more successful ARCJET operations
>
> Dear All,
>
> The arc-jet thruster has been invoked on Orbit 296, MA 118-135,
> which gave about 1 hour of thrusting gas only.
>
> The S2 TX is OFF from MA 100-180 to spare power for the ATOS.
> The gas generator for the ammonia draws about 120 - 130 W of power
> when cycled on by the thermostat.
>
> The IHU-2 is running and logging telemetry into a circular buffer
> and hold about 2.5 days worth of data. Downloaded telemetry from
> this 1h burn indicated positive power budget and everything looks
> nominally.
>
> The thrust on orbit 296 started at MA 121.4 and lasted for 3618s.
> The acceleration is guestimated to be 54E-6 m/s^2 ,
> and the direction of acceleration is towards alon 274, alat -2
> (the current attitude).
>
> Give or take the unknowns, the expected outcome of this was:
>
> Before After
> --------------------------------------------
> Epoch year 2001 2001
> Epoch time 173.12145 173.16312
> Inclination 5.2833 5.2833592
> R.A.A.N 180.71591 180.70361
> Eccentricity 0.815077 0.8150139
> Arg perigee 288.69088 288.71333
> Mean Anomaly 121.4 140.46836
> Mean motion MM 1.2711484 1.2710861
> Revolution 296 296
> SMA 36003.6 36004.773
>
> Perigee height 279.754 282.2427 <<< +2.5 km
> Apogee height 58971.166 58971.024
> --------------------------------------------
>
> So the perigee was raised by this 1h burn by about +2.5 km, but only
> a thrust rate of 50% was used.
>
> Since everything went so well, the computer onboard AO-40 was
> commanded to initiate 2h "burns" starting around apogee on orbit 297
> for the next three orbits.
>
> The first 2-hour burn stopped at Orbit 297 MA 142, which is 2001
> Jun 23 0154 utc. Again, all telemetry is looking good and we may soon
> expand to 4h "burns" and possibly increase the thrust level as well.
>
> While we haven't yet seen the latest NORAD data, some effects of the
> changing orbit should be soon noticeable.
>
> Indeed, we all are very happy with the successful results of the ATOS
> (Arcjet Thruster on OSCAR Satellite) so far.
>
> Some more information about the ATOS system is available here:
>
> http://www.irs.uni-stuttgart.de/RESEARCH/EL_PROP/PROJ/e_atos.html
>
>
> best 73s
> Peter DB2OS for the AO-40 team
--------------------------------------------
Name : JE9PEL/1 脇田
Mail : je9pel@jamsat.or.jp
URL : http://www.asahi-net.or.jp/~ei7m-wkt/
QTH : Yokohama, Japan
Date : Jun 24, 2001
--------------------------------------------