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Project Apollo Beta 7.0 released!
http://nassp.sf.net/wiki/Installation
25068 Posts in 2094 Topics by 2266 Members
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Author Topic: Apollo RTCC MFD  (Read 38686 times)
eddievhfan1984
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« Reply #180 on: July 04, 2016, 10:04:51 AM »

Here. I'd include a screenshot, but the server keeps throwing HTTP 500 when I try to upload.

The odd ranges intermittently pop up, but when they do, they don't change, almost like there's some kind of overflow.

* Apollo 7, 6-4 GO-NOGO.scn (117.66 KB - downloaded 64 times.)
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indy91
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« Reply #181 on: July 04, 2016, 10:44:10 AM »

Have you used the manual TIG and DV input on the Maneuver PAD page after calculating the deorbit maneuver? Because the manual input overwrites the TIG and DV used for the Entry PAD, while it still tries to reach the original landing coordinates. So the entry range can deviate significantly. A simple recalculation of the entry maneuver and then calculating the Entry PAD again solves the issue.

I guess this part of the code could use some rework, so that it is clear which DV is used for the Entry PAD. There are separate TIGs/DVs for the different calculation pages (Lambert, coelliptic, Entry etc.) but when the maneuver is calculated the TIG and DV are also copied to the "general" TIG and DV variables. That way you can have different TIG/DV on different pages, but also use any kind of maneuver solution for the PADs. Not a perfect system, the Entry PADs should probably only use the converged maneuver solution from the Entry page (corrected TIG and DV for finite burntime).
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eddievhfan1984
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« Reply #182 on: July 04, 2016, 12:40:01 PM »

I use the MCC's PAD and just load it into the MFD for reference, since the MCC PADs are not persistent with scenario reloads.
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indy91
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« Reply #183 on: July 05, 2016, 04:15:03 AM »

Yeah, as I said, it will try to use the manual loaded TIG and DV for the Entry PAD, but without having the associated splashdown latitude and longitude it will try to calculate the range to the wrong coordinates. That really is unintended behavior, so I will change the MFD to only use the TIG and DV from the Entry calculation page.
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kneecaps
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« Reply #184 on: July 27, 2016, 08:02:52 AM »

RTCC Lambert options  and Pad Request?

Is there a newer manual for RTCC ? I can only find one from Aug 2015. Lots of new/different options in Lambert and the Pad by the looks of things.

I'm especially interested in the Request option on the PAD and also how the Multi-Axis / X only option is working (looks to replace the old manual Z offset method?)

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"Okay. As soon as we find the Earth, we will do it."
- Frank Borman, Apollo 8

Current Work: ?? What next??

Future Work:
I know the AGC pretty well so anything need doing there?

On Hold/Completed:
SPS TVC in P40 issues.
P11 FDAI Error Needles (98%) complete. Comitted. Working A7 scenario.
P06 AGC Standby. Concluded. It's done by the AGC PSU.
Got us a complete AOH Volume II
indy91
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« Reply #185 on: July 27, 2016, 08:12:13 AM »

The most recent version of the manual is part of NASSP, under \Doc\Project Apollo - NASSP\Programmers Notes. It's not exactly a great manual, if you still have questions after reading it, then feel free to ask them here.
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kneecaps
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« Reply #186 on: July 27, 2016, 10:55:15 PM »

The most recent version of the manual is part of NASSP, under \Doc\Project Apollo - NASSP\Programmers Notes. It's not exactly a great manual, if you still have questions after reading it, then feel free to ask them here.

Thank you. The one place I didn't look Very Happy
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"Okay. As soon as we find the Earth, we will do it."
- Frank Borman, Apollo 8

Current Work: ?? What next??

Future Work:
I know the AGC pretty well so anything need doing there?

On Hold/Completed:
SPS TVC in P40 issues.
P11 FDAI Error Needles (98%) complete. Comitted. Working A7 scenario.
P06 AGC Standby. Concluded. It's done by the AGC PSU.
Got us a complete AOH Volume II
rcflyinghokie
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« Reply #187 on: August 20, 2016, 08:16:35 AM »

I do not know if this is a bug since it can be manually changed, but the SOI in the RTCC does not switch back to earth after switching to the moon.  I know it switches automatically to moon SOI but it never automatically switches back to the earth.  Any insight into this?
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indy91
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« Reply #188 on: August 20, 2016, 08:47:19 AM »

I do not know if this is a bug since it can be manually changed, but the SOI in the RTCC does not switch back to earth after switching to the moon.  I know it switches automatically to moon SOI but it never automatically switches back to the earth.  Any insight into this?

It doesn't automatically switch the SOI at all during an Orbiter session. When a scenario is loaded it will find the current SOI, but if you let a scenario run forever, then you need to switch it manually for some calculations. Ideally it would automatically detect the gravity reference all by itself, but that hasn't been implemented yet for all calculations. Especially map update/landmark tracking is still relying on the manual setting.
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rcflyinghokie
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« Reply #189 on: August 20, 2016, 06:39:22 PM »

It doesn't automatically switch the SOI at all during an Orbiter session. When a scenario is loaded it will find the current SOI, but if you let a scenario run forever, then you need to switch it manually for some calculations. Ideally it would automatically detect the gravity reference all by itself, but that hasn't been implemented yet for all calculations. Especially map update/landmark tracking is still relying on the manual setting.

Perfect thank you for the explanation.  I have been letting it run so that explains it Happy
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indy91
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« Reply #190 on: September 15, 2016, 08:10:35 AM »

A big LM update for the RTCC MFD. Already working  before for the LM was:

-REFSMMAT calculations and uplinks.
-State vector calculation and uplinks.

I had this update basically ready already, just a few more tests required. So here the changes for the LM:

-LM Maneuver PAD has been added. This will be displayed where the CSM Maneuver PAD would be, if LM is selected as the vehicle in the configuration menu. The MFD should be able to detect CSM vs. LM on scenario start, but checking doesn't hurt.
-REFSMMAT can be downlinked from the LM to the MFD so that the internal calculations of the MFD can be done with the actual present REFSMMAT in mind.
-P30 maneuver updates can now be uplinked to the LM
-Lambert targeted maneuvers can be calculated for the LM.
-An elaborate throttling scheme for the LM DPS is used, modelled after how P40 maneuvers were done during all the missions. This is necessary to take finite burntimes for the DPS into account. The calculations for the SPS are all based on 100% throttle throughout the burn. In the LM, if you just let the LGC do the burn then it will stay at 10% thrust for 26 seconds at then 100% for the remainder of the burn. So the RTCC MFD uses the throttle steps 10%, 40% and 100% as often used for the LM during the missions, especially Apollo 13. These throttle steps are taken into account for finite burntime calculations and are also displayed on the Maneuver PAD. This scheme can of course be changed in the future if it turns out that it isn't realistic.

Next up: Give the DOI burn a display on the MFD for the LM.
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eddievhfan1984
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« Reply #191 on: September 15, 2016, 08:34:42 AM »

Would it be possible to also compute PADs for the DOI abort scenarios? That's a thing I've had an issue with, where I wasn't quite sure what values to use for abort rendezvous planning (especially the early aborts, where there's already an interception built in to the abort orbit that just requires fine tuning...).
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indy91
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« Reply #192 on: September 15, 2016, 09:57:33 AM »

I absolutely plan to calculate the complete DOI, PDI etc. Data Cards. And there is already a function to calculate orbital midnight, so these abort maneuvers willl be calculated complete flexible for the correct lighting conditions.
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jalexb88
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« Reply #193 on: September 15, 2016, 10:07:24 AM »

I guess while were discussing it, and don't mean to put too much on your plate there Indy  Very Happy but here's a few other things I'm sure you've also thought of:

1. CSM plane change maneuver before lunar ascent

2. How are we going to go about ensuring proper landing site plane alignment for the planned time of landing? Is it going to be done on the last translunar MCC or will it be integrated into LOI-1? IE. calculate the required INC to be aligned with Tranquility base at X MET.
« Last Edit: September 15, 2016, 10:09:34 AM by jalexb88 » Logged
indy91
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« Reply #194 on: September 15, 2016, 10:17:30 AM »

1. CSM plane change maneuver before lunar ascent

One of the older CMC GSOPs has the equations for this. So they had planned to have a program onboard for this. I can easily implement that.

Quote
2. How are we going to go about ensuring proper landing site plane alignment for the planned time of landing. Is it going to be done on the last translunar MCC or will it be integrated into LOI-1, IE. calculate the required INC to be aligned with Tranquility base at X MET.

Right now we simply use inclination for the LOI-1. That got me <1NM crossrange at PDI. I have already implemented some preliminary functions for a more elaborate calculation to ensure the landing site is in-plane. The constraint for this was actually azimuth, not inclination and it was allowed to be varied within 2. The problem with taking out crossrange and also taking the desired azimuth into account is that during LOI-1 the ignition time must be varied. This can be very expensive in terms of fuel. In the actual RTCC they did a complete mission optimization and at least one MCC and LOI-1 have to be calculated together so that no fuel is wasted. These more elaborate calculations won't be ready soon. I'd say for now using the historical inclination is good enough.

EDIT: I have commited the DOI targeting. It is implemented as the 5th(!) option on the Lunar Insertion page. You have to give it the earliest GET for DOI, landing site latitude, landing site longitude, landing site altitude (always 0 in Orbiter 2010) and it will calculate the maneuver. Go to the LM Maneuver PAD, calculate and you have all the information you need for DOI. I guess the PDI PAD would be the next thing to implement...
« Last Edit: September 15, 2016, 10:24:57 AM by indy91 » Logged
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