Ascent advice
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thank you.
Ok Y YDOT CSM YDOT -YDOT. Can someone write a para about these i know what they are, what i'm interested in are any subtle gotchas . For example, you need to enter the negative ydot in the CSI burn . Ydot is negative already, so does that mean I put the opposite in i.e. --=+?
my v90e
y=-00008
ydot=--00002
psi(?)=+00003
On the G man doc there's a box to caputure N90 and CSM Ydot.
Do i need to carry out the plane change ? at what point is that decision made from a checklist point of view just before i get there.
cheers. i hope a12 has a better solution for rend !
Ok Y YDOT CSM YDOT -YDOT. Can someone write a para about these i know what they are, what i'm interested in are any subtle gotchas . For example, you need to enter the negative ydot in the CSI burn . Ydot is negative already, so does that mean I put the opposite in i.e. --=+?
my v90e
y=-00008
ydot=--00002
psi(?)=+00003
On the G man doc there's a box to caputure N90 and CSM Ydot.
Do i need to carry out the plane change ? at what point is that decision made from a checklist point of view just before i get there.
cheers. i hope a12 has a better solution for rend !
According to this handy document (https://history.nasa.gov/afj/ap10fj...-f+g-lunar-orbit-vol1-techniques-19690507.pdf) at para 4.11, page 4-26 (read ”y” as “ydot”, cut n paste didn’t carry the “dot” across):
“After CSI, rendezvous navigation is performed in both spacecraft. The CMP obtains the LM out-of-plane velocity, y, for LM CSI time + 29 minutes from the CMC using the out-of-plane RDZ Display Routine (R36). The y is voiced to the LM for the plane change maneuver. If y is less than two feet per second, the maneuver will not be performed. If y exceeds two feet per second, the plane change is accomplished using the External DV Program (P30) and RCS Thrust Program (P41).”
Typically, when you are computing CSI, CDH etc parameters in the LM, the CMP is doing the same in the CSM. Again, from p 4-25:
”The CMC estimate of y is used instead of the LGC estimate because rendezvous navigation analysis (Reference 5) shows that prior to TPI the CMC estimate of y based on SXT tracking is much more accurate than the LGC estimate as a result of RR angular errors. The y is voiced to the LM if it exceeds two feet per second for incorporation into the LM CSI Targeting Program (P32).”
If the Ydot value you already have from the LM’s P32 is negative, then I believe it stays negative.
“After CSI, rendezvous navigation is performed in both spacecraft. The CMP obtains the LM out-of-plane velocity, y, for LM CSI time + 29 minutes from the CMC using the out-of-plane RDZ Display Routine (R36). The y is voiced to the LM for the plane change maneuver. If y is less than two feet per second, the maneuver will not be performed. If y exceeds two feet per second, the plane change is accomplished using the External DV Program (P30) and RCS Thrust Program (P41).”
Typically, when you are computing CSI, CDH etc parameters in the LM, the CMP is doing the same in the CSM. Again, from p 4-25:
”The CMC estimate of y is used instead of the LGC estimate because rendezvous navigation analysis (Reference 5) shows that prior to TPI the CMC estimate of y based on SXT tracking is much more accurate than the LGC estimate as a result of RR angular errors. The y is voiced to the LM if it exceeds two feet per second for incorporation into the LM CSI Targeting Program (P32).”
If the Ydot value you already have from the LM’s P32 is negative, then I believe it stays negative.
indy91
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To add to what Thespacer said, Ydot is your out-of-plane velocity as viewed from the target (the CSM). So e.g. the CSM sees you drifting from left to right at 0.2 ft/s. So it is desirable to cancel that out. That's why you add the negative of that value to your CSI burn, as P32 doesn't do that on its own. Doing this doesn't completely cancel out your plane error, as you probably won't be exactly in plane with the CSM at the time of CSI. That is the Y, the 0.08NM in R1 when you call V90, basically how much you are to the left or right from the CSM. But by cancelling the "sideways" velocity out you are reducing the relative inclination as much as possible. If you have played around in Orbiter you know the Align Plane MFD, one of the default MFDs. It's like trying to reduce the RInc as much as possible without actually being at the ascending or descending node. And you will repeat that procedure for CDH and TPI. All really to avoid a dedicated plane change maneuver.
From those V90 numbers it looks like you have very little plane error, so the PC maneuver is likely not required. Checklist MFD wise, I noticed that the plane change maneuver hasn't been made optional. So what you should do is, if you want to skip the PC maneuver, is to skip over all the PC specific checklist lines. They start with a V34E to exit out of P33, so don't do that. And the PC procedures end with a (flashing V37) 33E to re-enter P33. So basically skip everything from the V34E to the 33E.
From those V90 numbers it looks like you have very little plane error, so the PC maneuver is likely not required. Checklist MFD wise, I noticed that the plane change maneuver hasn't been made optional. So what you should do is, if you want to skip the PC maneuver, is to skip over all the PC specific checklist lines. They start with a V34E to exit out of P33, so don't do that. And the PC procedures end with a (flashing V37) 33E to re-enter P33. So basically skip everything from the V34E to the 33E.
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thanks clear very clear.
I have some good news and some bad news
the good news, post csi, is that, in the words of Cpl Ferro, "we are in the pipe, 5 x 5"
the bad news is I have accidentally defaulted the AGS time bias to 90h instead of 120h (as AGS was reset in this period).
How should I deal with this ? I am just at the end of perform CSI with the above orbital alignment
Yes, I know I shouldnt be peeking at Orbit MFD
I have some good news and some bad news
the good news, post csi, is that, in the words of Cpl Ferro, "we are in the pipe, 5 x 5"
the bad news is I have accidentally defaulted the AGS time bias to 90h instead of 120h (as AGS was reset in this period).
How should I deal with this ? I am just at the end of perform CSI with the above orbital alignment
Yes, I know I shouldnt be peeking at Orbit MFD
indy91
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No big deal with the AGS time bias, unless you have been relying on the AGS solution for burning CSI. You just have to fix it and send the state vectors from the PGNS to the AGS again. So V47, change the time there to 120h, and then the 414+1, PRO on the DSKY, 414R. You know, that whole V47 procedure. That should fix the state vectors in the AGS, or rather its time tags. AGS time doesn't overflow until 72 hours (since 90h GET), but of course CSI and TPI times you entered in the DEDA will have used a different time bias than the state vectors it got from the PGNS.
The orbit looks ok, fairly elliptical for post CSI, but your apolune is probably a bit high and the DH that P32 came up with probably was something with 17NM (15 being nominal). Good enough.
The orbit looks ok, fairly elliptical for post CSI, but your apolune is probably a bit high and the DH that P32 came up with probably was something with 17NM (15 being nominal). Good enough.
during P33 i just set 0 0 0 for the v90 then skipped
... and add a recycle bin of course
i can now easilly follow flight plans thank you for that trauma
the a11 mfd checklist has been 100% so it was only the insertion start dap glitch and the p52 quiting the rr prog
the rr has busy motors ! It's like being on one of those retracting dog leashes
i get an op err when i enter +120 int r1 in the late stages of cdh checklist for sync
having a 3rd go at it
indy91
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Did you try to enter it with V21? The AGC doesn't actually let you enter only one register of a time input like this. Annoying, I know. So you have to do the whole thing: V25E +00120E +00000E +00000E
3k off in what?
Also, you can get rid of that program alarm light, if you want to. You won't see any new alarm if you keep it on. You should do a V05 N09E, read the program alarm numbers it shows you there (probably some harmless RR related alarm from locking on earlier) and then you press the RSET button to make the light and the alarm codes in N09 go away.
indy91
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Perfectly normal. P32 tries to adjust the DH to get the TPI time right (TPI happens when the CSM is at a specified elevation angle from the LM, the 26.6° you input in P32 and P34). The lunar launch window is defined as a launch that gets you a DH between 10NM and 20NM, 15 being nominal. Your DH seems to be something like 16.7NM. A bit off but well in the window.
Yes, P34 will adjust the TIG of TPI, that is normal. 4 minutes is fairly large, but definitely still acceptable. On repeated reycles (V32E) it shouldn't change too much anymore, but it will change by a few (or many) seconds every time. The mission techniques document says that a difference to the PAD value of the TPI time of 8 minutes is acceptable. And that is only for the case where TPI is 8 minutes (or more) early, to ensure that there is enough time between CDH and TPI. If TPI is late then you would always accept the number P34 comes up with.
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fab ! in the end it was 4 mins 3 seconds different
last couple of questions, will I get notified for Mid course correction 1 and 2. Although i'm 8 mins behind the nomilal timelines, it looks like my MCC1 needs to be done right away ? I know they are 15 mins apart but that probably means starting MCC1 10 mins or less before when you want the burn to happen ?
As i get closer to the CSM I am still not seeeing it appear on F9, is there an Orbiter range tihng somewhere that controls this. I let it fly upto 20nm as a test and still couldnt see the CSM from the LM.
Lastly, the braking phase, I have noticed that the speed gets down to aruond 100FPS by 10nm out and i've got the gates. Assuming i'm burning -Z to slow whilst the RR keeps me locked on. I will also read over the actual live documentation of the event but a few tips wouldnt go wrong. Just enough to stop me smacking into the csm
The great thing is any "cheaty" MFD for docking crashes in O2016 beta
Ascent-CSI-CDH-TPI-MCC-TPF is one heck of process. It's a great feeling to achieve each orital goal with such old and realistic tech.
Saw your announcement in the dev thread, i won't update.
Do you know of a good CSM and LM RPY XYZ pic showing all the axes a friend of mine was looking for soething better than my hand drawn crap.
last couple of questions, will I get notified for Mid course correction 1 and 2. Although i'm 8 mins behind the nomilal timelines, it looks like my MCC1 needs to be done right away ? I know they are 15 mins apart but that probably means starting MCC1 10 mins or less before when you want the burn to happen ?
As i get closer to the CSM I am still not seeeing it appear on F9, is there an Orbiter range tihng somewhere that controls this. I let it fly upto 20nm as a test and still couldnt see the CSM from the LM.
Lastly, the braking phase, I have noticed that the speed gets down to aruond 100FPS by 10nm out and i've got the gates. Assuming i'm burning -Z to slow whilst the RR keeps me locked on. I will also read over the actual live documentation of the event but a few tips wouldnt go wrong. Just enough to stop me smacking into the csm
The great thing is any "cheaty" MFD for docking crashes in O2016 beta Ascent-CSI-CDH-TPI-MCC-TPF is one heck of process. It's a great feeling to achieve each orital goal with such old and realistic tech.
Saw your announcement in the dev thread, i won't update.
Do you know of a good CSM and LM RPY XYZ pic showing all the axes a friend of mine was looking for soething better than my hand drawn crap.
Not really. You start P35 after the TPI burn and you’ll notice R2 of F 16 45 counts up (from TPI tig). Follow Checklist MFD with one important note: do not hit the final compute PRO until Tig+12mins; if you do it early or late, the Tig for MCC1 will not be exactly 15mins after TPI Tig, as it is supposed to be. Whether being off has any real effect, I do not know. Same goes for MCC2.
If N81 is sufficiently low in P35, you can probably make any corrections during TPF, when the CSM is in the LM’s COAS and you can use the X-pointer (in rendezvous radar mode) to cancel out any lateral or vertical drift.
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