RCS Best practice Apollo

sw34669

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Well done.
DET counting up is helpful, once you get used to it (and assuming you’ve set it correctly, not completely intuitive at the outset). The fact that it counts up from 0 at Tig helps to cross-check predicted BT with actual BT.
Interesting you’re having issues with V64 - it sounds like you’ve got another extended Verb running already, which is usually the reason why you’ll get an OPR ERR light. Did you go to P00 and then try V64?
it's always a poo isn't it :)
you may have a point i think i was running v20n16
and thank you i've come a long way since downloading NASSP a month ago, with some kind help here of course
Getting into the 69/190 orbit feels like an accomplishment
I wonder if my Oc rift s will work with it. Mind you, it would be a bit of a "cramped room simulator"
Have a nice evening.
 

indy91

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They actually added a feature to the event timer in the LM on Apollo 13:

The event timer was modified so that after it counted down to zero, it would count up automatically and thus reduce crew workload during critical events.

Not sure if this feature ever made it into the event timers in the CSM, I have to research that. In either case, we don't simulate that feature in NASSP.

Just for my interest, who owns NASSP ?

Nobody, NASSP is open source.
 
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sw34669

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LOI-2 now complete with an Ecc of 0.0002 61x59.9 orbit.

Still not sure i have my head around ORDEAL init (I see why they named it so) setting and two terms that seem to have a bunch of steps underneath in the post moon rev 2+3 checklist. I'm also not straight up to the moon so i figure i'm out a bit.

Go Inertial (is this just holding an attiude .......? ie using V49)
Go Orbital (I found a sub checklist in the MFD for establishing an intertial rate and that's worked but how to cancel it)

Any one liners of insight would be appreciated.
 

Thespacer

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Still not sure i have my head around ORDEAL init (I see why they named it so) setting and two terms that seem to have a bunch of steps underneath in the post moon rev 2+3 checklist. I'm also not straight up to the moon so i figure i'm out a bit.
ORDEAL is indeed an interesting name. The key thing to know is the average orbit height, in your case ~60NM. Make sure that figure is dialled into the Alt knob on the ORDEAL panel. Make sure Lunar is selected on the three way switch, and that FDAI 1 or 2 (your choice) is selected for Rate (not inertial, the default coasting/burn mode). From here, it is easiest to calibrate the “theta” setting (using the slew switch) if your spacecraft X axis is facing “forward” as much as possible, namely with 0 yaw. Next you’ll load V83 and look for the figure in R3, this is theta, or basically the angle between your spacecraft nose (the +X axis) and the local horizontal. If it is close to 0, then you are basically flying “straight and level” and your FDAI should read the same, if it isn’t then that’s when you slew it up or down till it’s the same angle as R3 in V83 reads.
Go Inertial (is this just holding an attiude .......? ie using V49)
Yes, basically holding the inertial attitude in fixed space as opposed to a fixed attitude relative to the local horizontal, which is what you would be doing if in Orb Rate (approx 0.05 degrees per second pitch up or down). V49 will get you to an inertial attitude and keep you there.
Go Orbital (I found a sub checklist in the MFD for establishing an intertial rate and that's worked but how to cancel it)
If it’s the procedure I’m thinking, it has a lot of button presses and octal entries? If so, there’s a few ways to cancel: going to P00, or switching to SCS, or changing the DAP load (V48), and probably other ways too. Which is the best? Depends, but they probably are all fine for your purposes, the differences are fairly nuanced (eg if you want to retain the center of your attitude deadband, then V48 should be used; if you don’t care about resetting your deadband, then switch to SCS).

Much more than one liners but hey...!
 

sw34669

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ORDEAL is indeed an interesting name. The key thing to know is the average orbit height, in your case ~60NM. Make sure that figure is dialled into the Alt knob on the ORDEAL panel. Make sure Lunar is selected on the three way switch, and that FDAI 1 or 2 (your choice) is selected for Rate (not inertial, the default coasting/burn mode). From here, it is easiest to calibrate the “theta” setting (using the slew switch) if your spacecraft X axis is facing “forward” as much as possible, namely with 0 yaw. Next you’ll load V83 and look for the figure in R3, this is theta, or basically the angle between your spacecraft nose (the +X axis) and the local horizontal. If it is close to 0, then you are basically flying “straight and level” and your FDAI should read the same, if it isn’t then that’s when you slew it up or down till it’s the same angle as R3 in V83 reads.

Yes, basically holding the inertial attitude in fixed space as opposed to a fixed attitude relative to the local horizontal, which is what you would be doing if in Orb Rate (approx 0.05 degrees per second pitch up or down). V49 will get you to an inertial attitude and keep you there.

If it’s the procedure I’m thinking, it has a lot of button presses and octal entries? If so, there’s a few ways to cancel: going to P00, or switching to SCS, or changing the DAP load (V48), and probably other ways too. Which is the best? Depends, but they probably are all fine for your purposes, the differences are fairly nuanced (eg if you want to retain the center of your attitude deadband, then V48 should be used; if you don’t care about resetting your deadband, then switch to SCS).

Much more than one liners but hey...!
thanks again
this confirms what I thought
What confufed me is that on lunar arrival, there are a couple of checklists, that talk about pitching down, but dont confirm if it's relative or absolute and talk of ORDEAL 315 pitch.
I just loaded up my last save from last night, and from what you're saying, i got it right or close enough the displayed theta vs FDAI1 set in orbital mode with 60nm set as altitude.
And yes, the procudure for Orbital rate is fully worked through in the NAV button of the checklists a few pages down, the same as putting into a PTC roll, but dealing with a different axis (I think putting a roll rate on for PTC(x) vs an pitch(y) one for Orbital). If someone can check my math :)

Indy - will ORDEAL hold an orbital rate when the Rate button is set to Orbital and CMC and auto cmc mode is set or does ORDEAL only deal with the presentation of pitch data on the FDAI's ? i.e. If the exam question is "Go Orbital" what are the exact steps, do i need to call the "go orbital" checklist to set the pitch rate in the DAP?

thanks all.
 

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1611758720391.png
 

indy91

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The ORDEAL only manipulates the pitch attitude shown on the FDAIs, nothing more. So the actual pitch rate has to be done manually, not even using the DAP. Later missions had a more automatic way of doing this and even the Apollo 11 Operations Checklist has a procedure to use the DAP to do the pitch rate, but I don't think it was actually used. Doing it manually, you only need a very small attitude rate, it's 0.05 °/s for lunar orbit.
 

sw34669

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The ORDEAL only manipulates the pitch attitude shown on the FDAIs, nothing more. So the actual pitch rate has to be done manually, not even using the DAP. Later missions had a more automatic way of doing this and even the Apollo 11 Operations Checklist has a procedure to use the DAP to do the pitch rate, but I don't think it was actually used. Doing it manually, you only need a very small attitude rate, it's 0.05 °/s for lunar orbit.
ah ok that explains a few things
so, when you say manually set a small rate is that using any of the att set / cmc att / sc cont / BMAG or cmc mode switches to establish it or doing a manual rcs pitch down (but then how can you measure that tiny rate or can you set the dap to 0.05 and full forward).,
Sorry for being thick, I get spacial inertial and orbital but not in the context of the exact systems i'd use to establish that tiny pitch rate in orbital.thx
 

indy91

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Fine control like that is easier using the SCS, the CMC can be a bit slow to react as it has to go through the computer. We have a decent wiki article about the SCS: http://nassp.sourceforge.net/wiki/SCS

What you want is SC CONT in SCS, Manual Attitude switch in Rate Cmd, BMAG mode switches in Rate 2 and then just look at the FDAI rate needles to establish the rate with the joystick/numpad. When the FDAI scale switch is in 5/1 then the full range of the attitude rate is -1°/s to 1°. So each small line is 0.2°/s. And you only want 1/4 of that, so it is a pretty small rate.
 

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larger problem., after the LM came upto pressure, no part of the checklist brought the power on. I'm now 81:30 in and have just run through the checklist to set circ breakers and switch positions. There is no LM power on. I checked back all the parts of the checklist since TLI there's nothing there to trigger bringing the LM online until 81h40m. What have i missed?
 

indy91

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Check if the CSM is still supplying power to the LM, LM power switch on panel 2 in the CSM, momentarily to reset and then to off. That can inhibit LM powering up. Aside from that, you aren't really doing much in the LM at that time anyway. Just checking if all the CBs and switches are in the expected position, a quick comm check and powering down again.
 

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tried that nothing. i've checked back through all the checklists i dont think there's anything earlier that brings the power on. I ran them all.

1611765324764.png
 

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all the actions in LM from 56h down dont flip any of the power switches by the looks of it.

1611765402833.png
 

indy91

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The power is switched on in the comm activation checklist at 83h GET, have you gone through that? The "Initial CB Positions" and "Initial Switch Positions" checklist just make sure the LM is in the right configuration before doing anything else. They don't power up the LM.

One thing that can be confusing is that no talkbacks are showing anything until they themselves have power. So the LM might already operate under its own power and some lights or so are on, but no display will be showing anything. Only when the signal conditioner circuit breakers are pushed in will they show something.
 
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sw34669

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looking at the A11 spreadsheet LM flightplan sheet i found these , that seem to be missing from the checklists. Not sure what has to be done now cant get the power on as I think the LM should have been running since 56h?
1611766584616.png
 

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sw34669

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The power is switched on in the comm activation checklist at 83h GET, have you gone through that? The "Initial CB Positions" and "Initial Switch Positions" checklist just make sure the LM is in the right configuration before doing anything else. They don't power up the LM.

One thing that can be confusing is that no talkbacks are showing anything until they themselves have power. So the LM might already operate under its own power and some lights or so are on, but no display will be showing anything. Only when the signal conditioner circuit breakers are pushed in will they show something.
ah not at 83 yet i thought it was earlier according to the sheet above from the PA docs directory checklist sheet.
 

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That all comes much later. Next to the line 72 for EPS Activation is a 346800 and MISSION_TIME. That is in seconds is equal to 96h20min GET. So that happens when you are activating the LM for the actual descent.

In that Flightplan sheet for the Checklist MFD you are currently doing lines 33 to 59. The majority of work is done in sub-checklists like that "Initial CB Positions" and "Initial Switch Positions". But aside from the comm check there is not much going on really, not until the next day.
 

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right thanks and is the docking angle on the tunnel simulated and if not what's the docking angle used is it zero?
 

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Yep it's always zero, not simulated yet.
 

sw34669

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ORDEAL is indeed an interesting name. The key thing to know is the average orbit height, in your case ~60NM. Make sure that figure is dialled into the Alt knob on the ORDEAL panel. Make sure Lunar is selected on the three way switch, and that FDAI 1 or 2 (your choice) is selected for Rate (not inertial, the default coasting/burn mode). From here, it is easiest to calibrate the “theta” setting (using the slew switch) if your spacecraft X axis is facing “forward” as much as possible, namely with 0 yaw. Next you’ll load V83 and look for the figure in R3, this is theta, or basically the angle between your spacecraft nose (the +X axis) and the local horizontal. If it is close to 0, then you are basically flying “straight and level” and your FDAI should read the same, if it isn’t then that’s when you slew it up or down till it’s the same angle as R3 in V83 reads.

Yes, basically holding the inertial attitude in fixed space as opposed to a fixed attitude relative to the local horizontal, which is what you would be doing if in Orb Rate (approx 0.05 degrees per second pitch up or down). V49 will get you to an inertial attitude and keep you there.

If it’s the procedure I’m thinking, it has a lot of button presses and octal entries? If so, there’s a few ways to cancel: going to P00, or switching to SCS, or changing the DAP load (V48), and probably other ways too. Which is the best? Depends, but they probably are all fine for your purposes, the differences are fairly nuanced (eg if you want to retain the center of your attitude deadband, then V48 should be used; if you don’t care about resetting your deadband, then switch to SCS).

Much more than one liners but hey...!
smashing summary of both ptc bbq and orbital pitch fork
 
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