Tag: Oscar 40

Peter Guelzow, DB2OS, reports that Victor Kudielka, OE1VKW did an analysis some weeks ago and was the first to discover some odd changes in the Mean Motion of AO-40.

It appears that the eccentricity may have changed, but it is also influenced by other effects and can not be used alone to evaluate possible changes in AO-40 s orbit. Viktor has some expanded diagrams of mean motion and eccentricity, as well as for the heights of peri- and apogee and their velocities on his home page:
http://cacofonix.nt.tuwien.ac.at/~oe1vkw/ao40/2004.html

Viktor noted, I am unable to judge which points are just imprecise measurements and what are the influences of data smoothing or other manipulations. The only big enough effect is the change in mean motion Peter continues, If you look carefully on the data, you will see that the orbit change already happened *before* the sudden battery event. We can only speculate, that it is the battery. It could be indeed also some remaining fuel? Peter added. The thrust phase is also much longer than the battery event, not only a few hours or days. Perhaps,could be smoothing/manipulation of the NORAD data too. There is room for a lot of speculation.

Peter concluded, Assuming the S/C mass to be 400kg, than this change is due to an impulse of 40 kg m/s or equal to 5 minutes of hot Arcjet firing.I have no idea if the battery is capable to do this. Indeed, if it is shortened it will get glowing hot and vent everything.

[ANS thanks Peter, DB2OS for the above information]

Klla: ANS

Hi Keith,

unfortunately there are no news to report.. Our command stations are still continuing to try to recover the bird, including during July, but so far without success.

As reported in my P3-E presentation during the AMSAT-UK colloquium,Viktor Kudielka OE1VKW (again) noticed some changes on the Mean Motion of AO-40, which may or may not be related to the battery incident.

There is currently not enough data available and further analysis will be necessary before we can even speculate what might have happened.

We will keep everyone informed, when there is more data available. Perhaps at the AMSAT-NA Symposium..

73s Peter, DB2OS

Klla: amsat

As the table below demonstrates, the mystery effect has taken A0-40 into highly unfavorable ALON. Attempts at communication are likely to be futile until conditions improve in early and mid July. Note that unfortunately
optimum squint in late July corresponds with a very bad solar angle….stay tuned.

AO-40 ATTITUDE – PRECESSION BEHAVIOR / W4SM
Mystery Effect = -11.800 degs ALON/week

DATE ALON ALAT SA ILL%
– —————————————————
2004 May 10 [Mon] 157.6 -0.9 57.5 53.8
2004 May 12 [Wed] 154.0 -0.9 62.3 46.4
2004 May 14 [Fri] 150.3 -0.9 67.0 39.0
2004 May 16 [Sun] 146.6 -0.9 71.4 31.9
2004 May 18 [Tue] 142.9 -0.9 75.2 25.5
2004 May 20 [Thu] 139.2 -0.9 77.8 21.1
2004 May 22 [Sat] 135.5 -0.9 78.5 20.0
2004 May 24 [Mon] 131.8 -1.0 76.8 22.8
2004 May 26 [Wed] 128.1 -1.0 73.6 28.3
2004 May 28 [Fri] 124.4 -1.0 69.5 35.1
2004 May 30 [Sun] 120.7 -1.1 64.9 42.4
2004 Jun 01 [Tue] 117.0 -1.1 60.2 49.8
2004 Jun 03 [Thu] 113.3 -1.1 55.2 57.0
2004 Jun 05 [Sat] 109.6 -1.2 50.2 64.0
2004 Jun 07 [Mon] 105.9 -1.2 45.2 70.5
2004 Jun 09 [Wed] 102.2 -1.3 40.1 76.5
2004 Jun 11 [Fri] 98.5 -1.3 34.9 82.0
2004 Jun 13 [Sun] 94.9 -1.4 29.8 86.8
2004 Jun 15 [Tue] 91.2 -1.4 24.6 90.9
2004 Jun 17 [Thu] 87.5 -1.5 19.5 94.3
2004 Jun 19 [Sat] 83.8 -1.5 14.3 96.9
2004 Jun 21 [Mon] 80.1 -1.6 9.1 98.7
2004 Jun 23 [Wed] 76.4 -1.6 3.9 99.8
2004 Jun 25 [Fri] 72.7 -1.7 -1.3 100.0
2004 Jun 27 [Sun] 69.0 -1.8 -6.5 99.4
2004 Jun 29 [Tue] 65.3 -1.8 -11.6 97.9
2004 Jul 01 [Thu] 61.6 -1.9 -16.8 95.7
2004 Jul 03 [Sat] 57.9 -1.9 -22.0 92.7
2004 Jul 05 [Mon] 54.2 -2.0 -27.2 88.9
2004 Jul 07 [Wed] 50.5 -2.1 -32.4 84.5
2004 Jul 09 [Fri] 46.8 -2.1 -37.5 79.3
2004 Jul 11 [Sun] 43.1 -2.2 -42.6 73.6
2004 Jul 13 [Tue] 39.4 -2.3 -47.8 67.2
2004 Jul 15 [Thu] 35.7 -2.3 -52.8 60.4
2004 Jul 17 [Sat] 32.0 -2.4 -57.9 53.2
2004 Jul 19 [Mon] 28.4 -2.4 -62.8 45.7
2004 Jul 21 [Wed] 24.7 -2.5 -67.6 38.1
2004 Jul 23 [Fri] 21.0 -2.5 -72.1 30.7
2004 Jul 25 [Sun] 17.3 -2.6 -76.2 23.9
2004 Jul 27 [Tue] 13.6 -2.7 -79.1 18.9
2004 Jul 29 [Thu] 9.9 -2.7 -79.9 17.5
2004 Jul 31 [Sat] 6.2 -2.8 -78.2 20.5
2004 Aug 02 [Mon] 2.5 -2.8 -74.7 26.3
2004 Aug 04 [Wed] 358.8 -2.8 -70.5 33.4
2004 Aug 06 [Fri] 355.1 -2.9 -65.8 41.0
2004 Aug 08 [Sun] 351.4 -2.9 -60.9 48.6
2004 Aug 10 [Tue] 347.7 -3.0 -56.0 56.0
2004 Aug 12 [Thu] 344.0 -3.0 -50.9 63.1
2004 Aug 14 [Sat] 340.3 -3.0 -45.8 69.7
2004 Aug 16 [Mon] 336.6 -3.1 -40.6 75.9
2004 Aug 18 [Wed] 332.9 -3.1 -35.5 81.4
2004 Aug 20 [Fri] 329.2 -3.1 -30.3 86.3
2004 Aug 22 [Sun] 325.5 -3.1 -25.1 90.6
2004 Aug 24 [Tue] 321.8 -3.2 -19.9 94.0

Klla: amsat

Tyvrr s hrs det fortfarande inget frn Oscar-40 och det kommer ingen ny information frn kommando stationerna.

Klla: amsat

Hej!

Det finns inte mycket att rapportera om AO40 men en av kontroll stationerna anser sig ha hrt ngot som kan tnkas vara en signal frn AO40.

ls nedan.

***************
Yes, we already thought about this idea.. but the thing
must be reproducable, which seems not to be the case
at the moment.. So we probably have to be more patient.

73s Peter DB2OS

William Leijenaar wrote:

> Hi AMSATs,
>
> Great to hear that at least some signals were heared
> from AO40.
>
> When IHU and the L-Band are working but not the TX
> completely, it is maybe possible to upload a small
> program that measures the battery voltage and sends
> the value back to earth in CW, by just switching
> on/off the TX…
>
> Its at least a small communication :o)
>
> Just an idea…
>
> 73 de LU/PE1RAH
> William in Buenos Aires
>

Klla: amsat

Lser fljande p AMSAT-DLs hemsida:

Today during the period 0310 to 0320 UTC (orbit 1541) I observed the following.
Prior to issuing the command sequence we tune around the beacon frequency, taking note of the noise spectrum . No variance in amplitude detected, just clean white noise. At 0310, commenced sending a 12 block sequence, 3 * (Reset,Tx-Off,Reset,Tx-On).

At the completion of the sequence, again tuned around the beacon frequency, and noted a noise peak of 4 to 5 db, in the vicinity of expected beacon frequency. The width of this peak was about 5 kHz. Listened to it for about 15 seconds and then sent a Reset, Tx-Off command and the noise peak disappeared, approximately 2 seconds after the Tx-Off block was completed.

Completed my session with a number of Aux-Batt commands, but did not attempt the Tx again. Range was nominally 12000/15000 kilometres during command period. Was using my last calibrated uplink frequency.

This tends to suggest that the IHU and L Band Rx are operational. Bus voltage insufficient to open that damn relay. Considering SA=-72, the remaining cells are holding up well. Hope this makes your day, like it has mine.

Colin Hurst, VK5HI
for the AO-40 Command Team

Klla: AMSAT-DL