Orbiter Video Thread

indy91

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A short video with NASSP and the AGC emulator showing the Apollo 14 procedure that was used to prevent an abort caused by their faulty abort button. It also shows what happens when you don't use the procedure and follow the nominal timeline for Powered Descent Initiation. Spoiler: the computer will start the abort maneuver at the instance of ignition.

For Apollo 15 and later the computer had a simple crew procedure for ignoring both of the abort buttons. This is just one of the fun things you can do with the flown AGC software!
 

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Project Apollo NASSP 8.0 Alpha - Masking the Abort Discrete on Apollo 14 - YouTube

A short video with NASSP and the AGC emulator showing the Apollo 14 procedure that was used to prevent an abort caused by their faulty abort button. It also shows what happens when you don't use the procedure and follow the nominal timeline for Powered Descent Initiation. Spoiler: the computer will start the abort maneuver at the instance of ignition.

For Apollo 15 and later the computer had a simple crew procedure for ignoring both of the abort buttons. This is just one of the fun things you can do with the flown AGC software!

I'm not claiming I know the AGC, but I think you might have a problem. I remember reading that they changed to P71 for ignition... but you still have P63. I went and found this page which details this issue, and according to this part...
Fortunately, another path in the Abort Monitor Routine to close this window of vulnerability was found -- MODEREG: the Mode Register memory location that held the number of the program or "major mode" that was currently running. That register was accessed mainly for the PROG display on the DSKY, but was also checked by the Abort Monitor Routine in case P70 or P71 was already running. If an abort was the current major mode, there was no need to start a new one.
...the DSKY should be displaying P71.
 

indy91

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I'm not claiming I know the AGC, but I think you might have a problem. I remember reading that they changed to P71 for ignition... but you still have P63. I went and found this page which details this issue, and according to this part...

...the DSKY should be displaying P71.


Good question. I had to do a bit of research before I found the answer.

First, changing the value of the mode register (MODREG, address 1010) in the erasable memory doesn't actually change the program that is running, so even if MODREG is 71, the AGC still runs all the routines for Program 63.

The reason for the DSKY still showing 63 is that the mode register doesn't get written to the DSKY every so often. When you change the program in the AGC with Verb 37 (e.g. V37E 63E) the routine first checks if the program number is valid (AGC doesn't actually have 99 different programs), then it writes the program number from the user input to MODREG and then once, just once, updates the program number that gets written to the DSKY. In the DSKY there are latching relays for every display, so if the computer never writes a new program number to the output channel for the DSKY again, which it doesn't in normal operation, then the "63" on the DSKY won't change.

There are a few ways to update the DSKY from the mode register again though. There is a verb to artificially cause a restart (Verb 69). If I use that then the DSKY gets an updated program number and it now says 71.
 

martins

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Creative use of the hover engines, I like it! Do you do active terrain avoidance when coming over the foothills, or was it just lucky that nobody scraped their behinds on the hilltops? :lol:
 

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Creative use of the hover engines, I like it! Do you do active terrain avoidance when coming over the foothills, or was it just lucky that nobody scraped their behinds on the hilltops? :lol:

:lol::lol::lol: No there was no luck, the autopilot has a rudimentary terrain detection to avoid collisions. The autopilot will point the base and if the base is behind a mountain, it will point the mountains peak (+75m at the moment I guess) :thumbup:. So if the ship is longer that 150m then... :hailprobe:
Ok, I'm not sure that this is always the perfect path regarding deltaV, but it's the path which makes the most fun :lol:.
But I don't know if it was necessary to use this in the video so maybe you havn't seen it...
But you see it here: [ame="https://www.youtube.com/watch?v=JiSaHha-64M"]Orbiter Baseland Demo - YouTube[/ame] (I allready posted this video here)
The terrain is scanned with a resolution of 10m with oapiSurfaceElevation(...) in flight vector direction and in each simulation step, it scanns 1000m more forward between the ship and the landing target. So I have 100 calls of oapiSurfaceElevation per simulation step per active vessel (only if it's using the autopilot) which is ok. First I scanned the whole distance between the ship and the landing target every second or so, but this needed to many ressources, specialy if you have four gliders then you need to do this four times. But now it's ok... :thumbup:
 
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MaxOrbite

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Little sharing

My last two Orbiter videos. I wont share the others because ... meh.

First one is a side-by-side launch comparaison of the last Discovery flight with Orbiter 2010 using Shuttle-Fleet.

Second one is something that is clearly inspired by 2001.
[ame="https://www.youtube.com/watch?v=7-9VdUlZsW4"]Orbiter Film - Jupiter Slingshot - YouTube[/ame]

Hope you enjoy ! :cheers:

EDIT : Skin used in Jupiter Slingshot now available to download here, in case you are interested. :) http://francophone.dansteph.com/?page=addon&id=243&language=english
 
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wedesoft

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Lunar excursion with Orbiter 2016 and XR2

Here is my attempt at a flight from KSC to Brighton Beach. In the first video a suitable launch date and time is chosen (30th September 2017, 11:00 UTC) followed by a SCRAM ascent. The second video is about flying to the moon including corrective maneuvers. The third video then is a landing at Brighton Beach spaceport.


The videos where recorded with OBS Studio. If I find some quiet time, I'll record a flight back.
Any feedback and comments welcome.
 

indy91

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[ame="https://www.youtube.com/watch?v=PP-LzofxsKA"]Project Apollo NASSP 8.0 Alpha - Landing near Tycho crater with Zerlina 56 - YouTube[/ame]

So here is something very special. This video shows a lunar landing in NASSP with Zerlina 56. Zerlina was a development branch of the LM software for the Apollo Guidance Computer, the main branch being called Luminary. In the past few months Don Eyles, one of the original LGC developers, has contributed all the LGC source code in his personal collection to the Virtual AGC project. That includes the software flown in the LMs of Apollo 10, 12 and 15-17. But he also still had the source code for Zerlina 56, Zerlina being his personal development branch that he worked on in 1970-1971.

The main reason for creating this development branch was to test a Variable Servicer. The nominal guidance cycle time of the lunar landing programs of the LGC was 2 seconds. If the computer had more tasks to do than it could process in these 2 seconds, then the computer dropped the tasks with the lowest priority and the famous 1201/1202 alarms happen. This is of course what happened on Apollo 11. With the Variable Servicer the 2 seconds guidance cycle could be extended to execute all tasks above a certain priority. So the Apollo 11 issue or even a more severe issue with the computer workload wouldn't cause anything bad, because the guidance cycle is then long enough to do all the important calculations. The Variable Servicer was never flown on an actual mission. The Software Control Board thought it was too big of a change to the flight proven software, I think. And at the time of its conception (about 1971) the development for the LM software was winding down anyway. The video doesn't really show the Variable Servicer in action, it's a nominal landing without computer problems. There might be some ways to artificially steal computer cycles so that the computer gets overloaded and has to extended the guidance cycle. I'll try to figure that out.

Another feature of Zerlina that was never included in the flight software was a reworked Program 66 (final landing program), based on some suggestions by John Young. The P66 changes are explained and fully shown in the video and the video description, so I am simply referring to that here. The changes allow for more precise automatic landings and small translations while hovering over the lunar surface.
 

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Return from lunar excursion with Orbiter 2016 and XR2

Here is the return trip from Brighton Beach to KSC. First a good parking orbit and eject orbit is planned and flown. In the second video an aerocapture is performed. The third video shows the reentry phase and the final video is the landing on the 5000+ meter runway which took a few attempts :blush:

 

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Hello,

this is a short video how to use BaseLand.

the scenario in this video is from Tex's great "jorney to saturn" series (Mission 038).

Different to Texs original video, I decreased the orbit first using Base Synch MFD. Make sure that the altitude over your landing site is not to much to get it working corectly.

For this, use the "LL" button in the Base Synch MFD to enter latitude and longitude (-65 and -53).

Then decrease the orbits altitude. I used translation RCS at about 1 minute in the video. I decreaced "Alt" from about 10km to 450m.

I gues this is also the most efficent way to land on a specific target.

Hope that helps a bit of understanding how to use it :)

[ame="http://youtu.be/HY0vAh773Bg"]Orbiter Baseland at Rhea - YouTube[/ame]
 
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HAL9001

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After Orbiter hadn't been working for me for a while I got it back to running, so I'm kinda digging up my old account again :p
 
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