Check RTCC comutations for SPS burn planner at LOI | Reentry - A Space Flight Simulator | Page 1

rancid flint Aug 23, 2022, 11:03 PM

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MM plan : 60x60 no LM - Result 60x14 (RTCC)
Solo player request 60x60 LM attached - Result 60x8 (SPS Burn Planner)

dusty stratus Aug 23, 2022, 11:05 PM

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My thought was that it could be adding the LM or parts there-of (say dry-mass) when it shouldn't, possibly adding it twice

rancid flint Aug 23, 2022, 11:06 PM

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Yeah but why would the burn be bad with the LM attached

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Reference solo player post : #🌎general message

dusty stratus Aug 23, 2022, 11:07 PM

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Maybe it's adding an LM to the launch dry-mass or something?

rancid flint Aug 23, 2022, 11:07 PM

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I mean we got errors with both LM docked and LM undocked

unreal peak Aug 23, 2022, 11:07 PM

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look we didn't crash and die horribly

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that's the important part

dusty stratus Aug 23, 2022, 11:07 PM

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Yeah my thought is that it's adding an extra LM

rancid flint Aug 23, 2022, 11:08 PM

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You mean an LM on top of the LM?

dusty stratus Aug 23, 2022, 11:08 PM

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Yeah

rancid flint Aug 23, 2022, 11:08 PM

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in the weights?

dusty stratus Aug 23, 2022, 11:08 PM

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or something

unreal peak Aug 23, 2022, 11:08 PM

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multiplication

rancid flint Aug 23, 2022, 11:08 PM

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Mmmh, since Petri is "cheating" if the weights are off, that's not wrong per se....

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But I'm not sure V48 is actually impacting SPS computations

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IRL it shouldn't but in game I don't know.

dusty stratus Aug 23, 2022, 11:09 PM

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That should be fairly easy to check

unreal peak Aug 23, 2022, 11:10 PM

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set the weight to 99999

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on both

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loll

rancid flint Aug 23, 2022, 11:10 PM

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Well, I always input actualo weights in my V48, but it's been a long time since I've done an LOI

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Never got issues on other SPS burn though

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Like TEI or deorbit

unreal peak Aug 23, 2022, 11:11 PM

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rancid flint Well, I always input actualo weights in my V48, but it's been a long time since ...

it's my specialty

dusty stratus Aug 23, 2022, 11:11 PM

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Calculate a burn at a set time, note the burn-time, then change the weights in V48 by a lot (say half the weight), and redo the calculation and check that burn-time

rancid flint Aug 23, 2022, 11:11 PM

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Maybe wait for Petri to have a look at the issue before we go further with assumption? Then he could guide us to things to test.

dusty stratus Aug 23, 2022, 11:11 PM

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For the bigger problem I have a thought:

Revert back to an earlier version of the game, go through TLI, enter lunar SOI, save
Calculate the LOI on the old build, write down the length of the burn (optionally other numbers)
Switch to current build, load save, redo step 2
Do one flight with the opposite

rancid flint Aug 23, 2022, 11:12 PM

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For MM I thought burn went bad because FDO and Myself were toying with the RTCC at the same time.

dusty stratus Aug 23, 2022, 11:12 PM

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Could be

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Did you tell the DAP it was LM-less?

rancid flint Aug 23, 2022, 11:12 PM

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Yeah of course

dusty stratus Aug 23, 2022, 11:13 PM

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Remind me again, can you program the LM weight separately?

rancid flint Aug 23, 2022, 11:13 PM

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I'm pretty sure we got everything right on that burn

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Yeah R2 in second screen of V48

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R1 is CSM weight

dusty stratus Aug 23, 2022, 11:13 PM

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Did you set R2 to 0?

rancid flint Aug 23, 2022, 11:14 PM

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We did

dusty stratus Aug 23, 2022, 11:14 PM

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hm

rancid flint Aug 23, 2022, 11:14 PM

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But as I said, Petri said that if weights were too much of charts, game uses actual weights so...

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Shouldn't impact anything

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And Burn time is computed on ground

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so without V48

dusty stratus Aug 23, 2022, 11:15 PM

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Yeah I just wonder if the game is ignoring something

rancid flint Aug 23, 2022, 11:16 PM

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Looks like an ISP difference between burn planner and actual SPS

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Because, on inertial, dV is dV, whatever your weight.

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Also, BT was 1 minute shorter than intended

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Like IIRC we intended 5:15ish and got 4: something

dusty stratus Aug 23, 2022, 11:18 PM

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So you burned 4: something?

rancid flint Aug 23, 2022, 11:18 PM

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Yeah

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Burn was shorter

dusty stratus Aug 23, 2022, 11:18 PM

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That should've gotten you a higher Pe than planned, not higher

rancid flint Aug 23, 2022, 11:18 PM

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That's why I'm thinking ISP

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First I thought user error, but with that solo report...

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Since DAP doesn't impact SPS burn at all

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Well not at all...

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But, shouldn't be that much XD

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I'll try with good and wrong DAP settings on weights

dusty stratus Aug 23, 2022, 11:20 PM

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Wouldn't the SPS burn system have to know how much the capsule weighs?

rancid flint Aug 23, 2022, 11:21 PM

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dV is derived from PIPA

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So technically... No.

dusty stratus Aug 23, 2022, 11:21 PM

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I meant for calculating the acceleration for a planned burn

rancid flint Aug 23, 2022, 11:21 PM

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To compute burn time in the AGC yes

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But the AGC cut the burn at 0 dV

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Wich is derived from PIPA wich is pure acceleration measurement

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Whatever your weight is, 1m/s is 1m/s

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You'll burn more or less fuel to get the same effect, but the measurement will be pure inertial

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Thus no weight involved

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In the end, the computed dV is probably wrong, BT is not the issue

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If there is indeed a bug

dusty stratus Aug 23, 2022, 11:35 PM

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rancid flint In the end, the computed dV is probably wrong, BT is not the issue

at 60nmi x 60 nmi around the moon you should have approx 1628.44 m/s, 5342.59 ft/s

rancid flint Aug 24, 2022, 7:55 AM

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Insertion burn was about 3300ft/s dV

dusty stratus Aug 24, 2022, 9:29 AM

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rancid flint Insertion burn was about 3300ft/s dV

hb post burn vel?

rancid flint Aug 24, 2022, 9:42 AM

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Don't remember exactly :/

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I may have it on stream on twitch though

radiant knot Aug 24, 2022, 12:23 PM

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Keep in mind that these long burns get quite unstable towards the end, esp. towards low eccentricity, the tangent needs to be perfect.

In real missions LOI was planned to insert the spacecraft to 60nmi X 170nmi. Then a circularization burn and a DOI burn would get it to a landing orbit. If you do it directly, use the map to see live orbit data, then hit PRO when you reach the "target" orbit to abort the rest of the burn. (Repost)

rancid flint Aug 24, 2022, 1:34 PM

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noted will try that way

#Check RTCC comutations for SPS burn planner at LOI