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Re: AO-40: more successful ARCJET operations



Great news, Peter!

When will full arcjet testing (both gas and electric power) begin?

73,

Jon
NA9D

on 6/23/01 5:08 AM, Peter Guelzow at peter.guelzow@arcormail.de wrote:

> 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
> 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
> 
> ----
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> 


-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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