Re: TLEs: SeaStar / OrbView 2 raised again

Bjoern Gimle (bjorn@tt-tech.se)
Mon, 25 Aug 1997 14:00:56 +0200

SeaStar's orbit was raised again around 8/24/1997 17:53
Several previous steps cannot be easily calculated, since
elements show that more than one maneuvre was made between
OIG elsets.
Latest elsets for SeaStar show high drag factors, and MM quickly
increasing - it seems to have a leak, or what?

#40 97037A             556 x 530
1 24883U 97037A   97236.71657085  .00131090  00000-0  83877-2 0   403
2 24883  98.2257 334.0732 0018338 334.9623  25.0902 15.07819805  3572
#41 97037A             565 x 547
1 24883U 97037A   97236.84955660  .00400992  00000-0  27711-1 0   412
2 24883  98.2155 334.2148 0013132 239.6851 120.3274 15.03586434  3591
#42 97037A             565 x 547
1 24883U 97037A   97236.84955291  .00354877  00000-0  24679-1 0   423
2 24883  98.2155 334.2148 0013132 239.6852 120.3080 15.03595142  3593
#44 File SELE0825.TLE: 565 x 547
1 24883U 97037A   97236.91610074  .00295639  00000-0  20713-1 0   445
2 24883  98.2169 334.2841 0012875 240.1377 119.8555 15.03631454  3609
#45 
1 24883U 97037A   97237.18227526  .00767686  00000-0  51912-1 0   453
2 24883  98.2311 334.5604 0013901 240.5318 119.5794 15.04025295  3645


David Irwin wrote (in a private mail):
> 
> Hi Bjoern,
> 
> Have you had the chance to produce an altitude plot against time, showing the climb of SeaStar from launch orbit of 310 km toward the on orbit nominal of 705 km?
> 
I have, but I'm not content with it, because my old program doesn't
produce decent lines between data for this kind of object, and the
buttons hide the first part, unless I extend the axes. So, rather
than amending that one, I started on one that could be released as
a utility. When I saw your mail, I just created a very simple 
32-line program for Windows, that will produce plots for one object
in one file for each chart. No other runtime options, but you can
modify the source if you like. 

(I can send the .gif file on request, and I may post it on my www
tree, when I also post the .rlz program and its .exe file)

To run my Windows .exe files you need realizer.zip from
http://www.algonet.se/~b_gimle/programs/ibmpc/index.htm,
to run source code you also need the launch.exe file
(also included in realizer.zip), and call it with
the name of the .rlz source file as argument.

Here is the program (not yet in my www area):
' This is just a quick-and-dirty way of reading TLE data for
' plotting MM vs. Epoch
TLE.file="*.tle"
WHILE TLE.file<>""
        INPUT "USSPACECOM object # (0=24883) ",\\
                  "Select a satellite for MM plot"; nr
        nr =    IF nr=0 THEN 24883 ELSE nr
        TLE.noa = Right$ ( NumToStr ( 100000 + nr ), 5 )
        TLE.no = nr
        TLE.file=StdOpen( TLE.file,"Two-Line Elements file","")
        IF TLE.file="" THEN: EXIT PROGRAM: END IF

        TLE.Format={"A2","R5","X11","R14","X20","R11"}
        TLE.Variable = {"Lno","SNo","X","Epoch","X","MMot"}
        FileImport ( TLE.file, _Text, _Plain, TLE )
        j = 0
        r1 = (LNo="1") AND (SNo=TLE.no)
        r2 = (LNo="2") AND (SNo=TLE.no)
        FOR i = StartValid( MMot )+1 TO EndValid(MMot)
                IF r1[i-1] AND r2[i] THEN
                        j = j+1
                        TLE.Epoch[j] =  Epoch[i-1]
                        TLE.MMot[j] =   MMot[i]
                END IF
        NEXT i
        MMchart = ChartNew ( 0; "MM vs. Epoch for USSPACECOM #"+TLE.noa
)
        ChartSetColor ( _NavyBlue; _AllData )
        MMmarks = ChartXYMark ( TLE.Epoch,TLE.MMot )
        ChartSetColor ( _LightYellow; _AllData )
        MMlime = ChartXYLine ( TLE.Epoch, TLE.MMot )
        ChartSetXaxis( 97215,97238)
        ChartSetYaxis( 15.0,15.9 )
        ChartControl ( _Show )

END WHILE


> This orbit raise was meant to take 6 weeks, but I suspect it will take longer?
> 
It is now in 565*547 km, more than half-way, after two weeks.

 Regards,
 Bjoern 

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