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Project Apollo - NASSP 6.4.3 released!
http://nassp.sf.net
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| | | |-+  S-N stage Planning Thread
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Author Topic: S-N stage Planning Thread  (Read 9882 times)
Graham2001
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« Reply #15 on: October 04, 2009, 06:12:04 PM »

Found that my anti-virus/spyware software was interfering with the flight data recorder so I've run two flights.

It would seem that changing the S-IVb parameters in the scenario affects the Autopilot. Shortly after the escape tower was ejected the spacecraft heading changed violently before settling down. After the S-II/S-Nb separation the third stage kept firing until all fuel was exhausted resulting in a very elliptical orbit (see attached screenshot).

The changed mass resulted S-II stage almost reaching the target orbit (185.2 by 185.2 km) as a result only a very short S-Nb burn would have been needed to circularise.

I've attached flight data recordings for both the baseline and the SVn launch.

Edit:I just realised that the empty weight of the S-Nb stage was too high, the corrected figures are below.

I3V 7936.3
T3V 360000.0
S4EMPTYMASS 9300.0
S4FUELMASS 40700.0

I've run the test using the figures above for the S-Nb, launch results were similar. Planned orbit was reached shortly before the S-II stage ran out of fuel. Had the autopilot been functioning it would have meant that the third stage and it's payload (CSM + the Apollo 6 LTA) would have reached it's parking orbit without the NERVA being fired. As it was the third stage was again allowed to burn to exhaustion resulting in a highly elliptical orbit. (See: SVn Test2 Final Orbit.png below).

Have attached the flight data recordings for this flight below.

I plan to run the three flights again using a CSM+LM as the payload.

* Baseline Launch.txt (37.35 KB - downloaded 352 times.)
* SIVN Launch.txt (39.87 KB - downloaded 411 times.)

* SVn Final orbit.png (78.11 KB, 789x565 - viewed 579 times.)

* SVn Test2 Final Orbit.png (78.2 KB, 788x566 - viewed 588 times.)
* SVn Launch2.txt (41.56 KB - downloaded 346 times.)
« Last Edit: October 05, 2009, 09:48:55 AM by Graham2001 » Logged
Graham2001
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« Reply #16 on: May 30, 2010, 10:35:25 AM »

Just to announce I plan to resume work on this project soon. Looking at some new information. See the discussion thread for the details.
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My lord, I aim a mile beyond the Moon.
Wm Shakespeare, 'Titus Andronicus'
Graham2001
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« Reply #17 on: November 27, 2010, 10:02:50 AM »

I'm planning to resume work on this with Orbiter 2010. Does the scenario file configuring of Thrust/ISP still work?
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My lord, I aim a mile beyond the Moon.
Wm Shakespeare, 'Titus Andronicus'
movieman
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« Reply #18 on: November 28, 2010, 12:30:24 PM »

I assume no-one has changed that, but I still haven't got Orbiter working on my new laptop... I should give it a try again when I get the chance!
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dseagrav
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« Reply #19 on: November 29, 2010, 12:40:21 PM »

Be warned, performance under Windows 7 is abysmal. If you have W7 it will be unacceptably slow. Anything using older versions of DirectX is crippled.

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Tschachim
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« Reply #20 on: November 30, 2010, 12:09:32 PM »

Be warned, performance under Windows 7 is abysmal.

Then perhaps Jarmo's new DirectX9 client is worth a try:
http://www.orbiter-forum.com/showpost.php?p=221090&postcount=147
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