Shuttle FDO MFD

[Gingin]

Nice

The FDO handbook doesn't say what the difference between e.g. LITO and NITI is. Maybe it's just a different name for the same thing

I saw also quite a lot of acronyms in Threshold and constraint that have the same meaning, maybe some past heritage of older designator (??)

 

[indy91]

I saw also quite a lot of acronyms in Threshold and constraint that have the same meaning, maybe some past heritage of older designator (??)

Yeah, probably something like that. One nomenclature for old FDOs, another for younger ones. :lol:

I'll just implement it like the FDO handbook says it should work.

 

[Gingin]

I found a fun one for a FD2 rendezvous, but that involves doing quite large OMS-2 and NC-1 burns that almost take the Shuttle up to the ISS altitude already. Probably not very realistic.

Fun indeed
I am working on that for STS 400 with Non SG






Also, I was trying to reproduce ISS fast rendez vous made by Soyuz. ( 4 orbits)


https://www.nasaspaceflight.com/2018/07/progress-ms-09-super-fast-4-hour-rendezvous/



Also tried some Gemini scenario with Rendez Vous Half an Orbit after Launch.
That works pretty well, and History of rendez vous book is a bible to have the correct profile on that

 

[Donamy]

Also tried some Gemini scenario with Rendez Vous Half an Orbit after Launch.
That works pretty well, and History of rendez vous book is a bible to have the correct profile on that

Where can you get that ?

 

[indy91]

Where can you get that ?

Here: https://ntrs.nasa.gov/search.jsp?R=20110023479

---------- Post added at 19:52 ---------- Previous post was at 19:21 ----------

New release: https://github.com/indy91/Shuttle-FDO-MFD/releases/tag/0.1.5-alpha

Bug fixes and rarely used maneuver and threshold options mostly. One of the rarely used maneuver types is NSR, which is a coelliptic burn. Only used a few times for Shuttle rendezvous (I know of STS-82 and some early missions) but often used by Gemini, Apollo and also some of the cargo vehicles that fly to the ISS.

Here a quick (and not complete) rendezvous plan for a rendezvous with multiple phases like Dragon 1 is usually doing: https://spaceflightnow.com/falcon9/003/images/demo1_600.jpg. Coelliptic orbits at 10km, 2.5km and 1.4km below the ISS orbit.

 

[GLS]

Finally trying again!

Of note so far is the NPC burn attitude being somewhat off: 156/033/046 vs 315/066/027 in SSU (it's probably an issue on SSU's side). Also, it made the RInc in the Align plane MFD go from 0.05º to 0º to 0.24º... :idk: so it seems it overburned a bit.

Of bigger note is me overshooting the ISS... AGAIN! :facepalm: The NH and NC-4 are now trying to get the vehicle back to the ISS.
This time, as I know a bit more about the MFD, I threw the flight plan out the airlock and changed the TI from M=1 to M=7.19 and DR=-8 to DR=8, and the dV requirements came down to something more realistic. The M=7.19 puts the TI burn at a node (can't add a CN secondary, so I had to try different M values to place the TI), and this way the MC-4 has now very little Y-component. Let's see how it plays out.

A question: the Y and YDOT values on the MET, I assume they are horizontal distance and rate to the target at the burn TIG, but in what units are they?

---------- Post added at 11:36 AM ---------- Previous post was at 11:11 AM ----------

A question: the Y and YDOT values on the MET, I assume they are horizontal distance and rate to the target at the burn TIG, but in what units are they?

Nop, not horizontal distance, but actually lateral distance. I'm fine tuning the TI TIG to have a small Y component in MC-4 and when I found a good TIG, the Y/YDOT for MC-4 is 0/0. Even with it being called Y and YDOT I never thought it was lateral... :facepalm:

 

[indy91]

Finally trying again!
Of note so far is the NPC burn attitude being somewhat off: 156/033/046 vs 315/066/027 in SSU (it's probably an issue on SSU's side).

Yep, I am using a different calculation method for those out-of-plane attitudes. I believe my calculation is correct and SSU is missing the handling of that special case, but I am not 100% on that.

Also, it made the RInc in the Align plane MFD go from 0.05º to 0º to 0.24º... :idk: so it seems it overburned a bit.

Not necessarily. If you are using the non-spherical gravity option only the inclination should be close to aligned, the LAN is biased so that the Shuttle "drifts" into the orbit of the target. If you are using spherical gravity then indeed RInc should be 0.0° after the burn.

Nop, not horizontal distance, but actually lateral distance. I'm fine tuning the TI TIG to have a small Y component in MC-4 and when I found a good TIG, the Y/YDOT for MC-4 is 0/0. Even with it being called Y and YDOT I never thought it was lateral... :facepalm:

Yep, Y is in feet, YDOT in ft/s. Sounds like a classic case of "a manual would have helped". I have the first version of that ready some time this weekend. What you should be looking for in the evaluation table is RANGE and PHASE. Range is the distance to the target in NM, phase basically the same in degrees. So you should be getting about 40NM and 8NM of range at the NC-4 and TI maneuver points.

 

[GLS]

Inside 200m!!
For some reason I had to make a second TI burn, and then the MC-4 (I think the RCS SEL burns need work) got me very close to the ISS! I probably should have used SPEC34 along the way, but I wanted to test the FDO MFD.

Yep, I am using a different calculation method for those out-of-plane attitudes. I believe my calculation is correct and SSU is missing the handling of that special case, but I am not 100% on that.

I know we have an issue with the TV ROLL for retrograde burns, so there could very well be more cases that aren't properly handled.

Not necessarily. If you are using the non-spherical gravity option only the inclination should be close to aligned, the LAN is biased so that the Shuttle "drifts" into the orbit of the target. If you are using spherical gravity then indeed RInc should be 0.0° after the burn.

I remember they both went off. Me using (again!) the wrong gravity setting probably messed things up.

So you should be getting about 40NM and 8NM of range at the NC-4 and TI maneuver points.

I remember that I was at about 80NM for the first TI... :lol: :facepalm:

 

[Tim13]

@Indy91, could you take a look at this video, and tell me why this error occured, and how to clear it? The trouble occurs at 01h06m mark of the video. I've just completed the first NC burn, have deleted the burn in the constraints table to begin setting up for the next burn(EXDV), but I received the error "could not find DR constraint for NC maneuver."

https://www.twitch.tv/videos/388911616

Thanks,

Tim

 

[GLS]

@Indy91, could you take a look at this video, and tell me why this error occured, and how to clear it? The trouble occurs at 01h06m mark of the video. I've just completed the first NC burn, have deleted the burn in the constraints table to begin setting up for the next burn(EXDV), but I received the error "could not find DR constraint for NC maneuver."

https://www.twitch.tv/videos/388911616

Thanks,

Tim

After deleting the NC-1 burn, you need to change NC-2 type to from EXDV to NC.

 

[Tim13]

After deleting the NC-1 burn, you need to change NC-2 type to from EXDV to NC.

I'm pretty sure I tried that later in the video, and could not get the DR constraint to clear.

Wonder if it's possible that once that error fires, the MFD is breaks?

I'm stepping out right now, and can't check....be back later.

Tim

 

[indy91]

The error message you are getting is from an outdated version of the MFD, so in any case I would suggest updating to the latest one: https://github.com/indy91/Shuttle-FDO-MFD/releases/tag/0.1.5-alpha

I can't find in the video where you tried changing the maneuver type of the NC-2 burn. But yeah, that's the solution after deleting the NC-1 maneuver the type of the NC-2 maneuver has to be changed, or else there is no maneuver to control the downrange distance at NC-4. That can be done the easiest with the MOD button to modify a maneuver. "1 NC NC-2" will change the 1st maneuver in the table to a NC type maneuver with the name NC-2. Then the "DR = -40" constraint has a maneuver again to target it.

---------- Post added at 10:24 ---------- Previous post was at 08:37 ----------

Next update: https://github.com/indy91/Shuttle-FDO-MFD/releases/tag/0.1.6-alpha

-Added a manual for the MFD. It doesn't have a tutorial yet, but it has full descriptions of every MFD page associated with the Orbital Maneuver Processor and all the various maneuvers options, so it should be quite useful as a reference.
-Added a Modifiy Secondary (MOS) button to the constraints table. Previously it was very inconvient to e.g. play around with the DV of a EXDV maneuver. You basically had to delete all 3 DV components and then readd them. Now you can simply edit it.

 

[GLS]

-Added a manual for the MFD. It doesn't have a tutorial yet, but it has full descriptions of every MFD page associated with the Orbital Maneuver Processor and all the various maneuvers options, so it should be quite useful as a reference.

Looks like I have something to read tomorrow at lunch. :thumbup:

 

[Gingin]

I read the manual, Very nice for those who don't have the FDO book, sum up well the essential infos we can find there

:thumbup:

I tweaked STS 400 scenario, good to save Atlantis

 

[Tim13]

The error message you are getting is from an outdated version of the MFD, so in any case I would suggest updating to the latest one: https://github.com/indy91/Shuttle-FDO-MFD/releases/tag/0.1.5-alpha

I can't find in the video where you tried changing the maneuver type of the NC-2 burn. But yeah, that's the solution after deleting the NC-1 maneuver the type of the NC-2 maneuver has to be changed, or else there is no maneuver to control the downrange distance at NC-4. That can be done the easiest with the MOD button to modify a maneuver. "1 NC NC-2" will change the 1st maneuver in the table to a NC type maneuver with the name NC-2. Then the "DR = -40" constraint has a maneuver again to target it.

---------- Post added at 10:24 ---------- Previous post was at 08:37 ----------

Next update: https://github.com/indy91/Shuttle-FDO-MFD/releases/tag/0.1.6-alpha

-Added a manual for the MFD. It doesn't have a tutorial yet, but it has full descriptions of every MFD page associated with the Orbital Maneuver Processor and all the various maneuvers options, so it should be quite useful as a reference.
-Added a Modifiy Secondary (MOS) button to the constraints table. Previously it was very inconvient to e.g. play around with the DV of a EXDV maneuver. You basically had to delete all 3 DV components and then readd them. Now you can simply edit it.

Thanks for the update. Just as a frame of reference, this was done with the FDO MFD I downloaded on 02-27-2019 at 1800GMT.

I'm assuming I can just overwrite the old FDO files with the new files?

Tim

 

[indy91]

Thanks for the update. Just as a frame of reference, this was done with the FDO MFD I downloaded on 02-27-2019 at 1800GMT.

Ah, I think I had released the previous version just an hour after that. I just noticed the different error message, that is all. The way the iterators are set up slightly changed, so I had also changed the error message. No big deal.

I'm assuming I can just overwrite the old FDO files with the new files?
Tim

Yep, just overwrite it all.

---------- Post added at 19:18 ---------- Previous post was at 19:13 ----------

I tweaked STS 400 scenario, good to save Atlantis

Ah, STS-400 is interesting. Flight Day 2 rendezvous, with just a single phasing maneuver setting up the rendezvous and NC-2 being what typically is NC-4 (or even NC-6 on a FD4 rendezvous). There is only so much catch-up that can be done in that time, so that rendezvous will be restricted to phase angles of up to 180°, roughly.

 

[Tim13]

When calculating the NPC burn, I kept getting a "too many iterations" error. What is usually the cause of this, and how can it be cleared?

I only got this when deleting all the burns before the NPC burn, which made NPC the first maneuver.

Tim

 

[DaveS]

Can someone write a simple tutorial on how to use this MFD? I'm making no progress at all beyond just adding a maneuver. I guess that comes from being a mostly GSE-guy.

 

[Tim13]

Can someone write a simple tutorial on how to use this MFD? I'm making no progress at all beyond just adding a maneuver. I guess that comes from being a mostly GSE-guy.

I've been making headway, but it's been slow. Lot's of trial and error...the story of my life.

I'm starting to think that deleting maneuvers after they are completed is asking for trouble. It seems that's when I start getting hard stops.

In any event, it's a cool MFD, and will make the SSU so enjoyable once I wrap my brain around it. Rome wasn't built in a day, and at my age, it keeps the neurons firing.

Tim

 

[indy91]

I'm sorry you guys keep on having problems. My next priority for the MFD is definitely to write a walkthrough of a mission as a tutorial, I hope that will help.

When calculating the NPC burn, I kept getting a "too many iterations" error. What is usually the cause of this, and how can it be cleared?

I only got this when deleting all the burns before the NPC burn, which made NPC the first maneuver.

NPC burns can be a bit of trouble for a maneuver timeline, because they don't happen at an apsis usually (apoapsis or periapsis) and with non-spherical gravity they won't even be at a fairly fixed TIG, because the common node with the target will be changing all the time. So the burn after the NPC burn usually needs some constraint to put it on an apsis (APS, APO or PER) or, what is always the most stable solution, even a fixed time (primary constraint T) as the input.

I'm starting to think that deleting maneuvers after they are completed is asking for trouble. It seems that's when I start getting hard stops.

I'm not sure what you mean by hard stop. What happens when you delete a maneuver? The maneuver plan should always become simpler because of that and show better iteration behavior. There are of course some modifications you need to make to a plan after deleting a maneuver, but those are pretty obvious, and if they aren't, I have already mentioned them in this thread.