[amsat-bb] Re: AO-40: more successful ARCJET operations

[Mineo Wakita <je9pel@xxxxxxxxxxxx>]

Thank you, Tom Clark / W3IWI.

I confirmed the equatorial radius of the oblate earth is 6378.140 km
(6378140 m = 637814000 cm) by a astronomical journal of Japanese.
As a result, this perigee height agrees to ~1 km with the results 
that Peter reported.

I corrected as the following (18),(19) and I reposted the EXCEL sheet.
http://www.ne.jp/asahi/hamradio/je9pel/a40range.zip


(18) r0=a(1-e^2)/(1+e*cos(s)) : Distance from the center of the earth
(19) r=r0-637814000           : Distance from the surface of the earth


The solution of this algorithm, the correction of W3IWI and JE9PEL :

                    Before      After
  Perigee height :   278.8        281.3  ....... +2.5 km
  Apogee height  : 58960.0      58959.7  ....... -0.3 km


The report of Peter Guelzow, DB2OS :

                    Before      After
  Perigee height :   279.754      282.2427  .... +2.5 km
  Apogee height  : 58971.166    58971.024   .... -0.1 km



Tom Clark / W3IWI, wrote:
> The equatorial radius of the oblate earth is 6378.160 km, larger 
> than the 6371 km you use. Since the inclination is only 5.3 deg, 
> it is appropriate to use the equatorial value.
> 
> Therefore, using your formulation, I come up with:
> 
> > The solution of this algorithm [posted by JE9PEL]
> >                     Before      After
> >   Perigee height :   286.0        288.4  ....... +2.4 km
> >
> > The report of Peter Guelzow, DB2OS
> >                     Before      After
> >   Perigee height :   279.754      282.2427  .... +2.5 km
> 
>   The JE9PEL perigee corrected by W3IWI:
>                       Before        After
>     Perigee height :   278.8        281.3  ....... +2.5 km
> 
> This agrees to ~1 km with the results that Peter reported. Since 
> the object of the "burn" was to raise perigee (with very little 
> change in apogee), and since a post-burn mean motion is not yet 
> available, I haven't bothered to examine the apogee differences.


----------------------------------------------
Name : JE9PEL/Mineo Wakita, JAMSAT member
Mail : je9pel@jamsat.or.jp
URL  : http://www.ne.jp/asahi/hamradio/je9pel/
QTH  : Yokohama Japan, GL:PM95TJ
Date : Jun 25, 2001
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