Project Multistage2015 - Development Thread

[boogabooga]

Would it help to simply lower the PEG interval time?

 

[fred18]

Nope: attitude control is run every frame anyway. Between a peg calculation and the other pitch is linear variated as per Peg theory, but still is controlled.

I need to smooth the input of the autpilot playing a bit with deadbands, i'll fine tune this and update very soon!

 

[1987VCRProductions]

My issue with making the Multistage2015 Saturn IB was figuring out how to mount the AAPO SLA, CSM, and LES combination to the top of it. In the scenario file, they're all considered the same spacecraft when together, but they're comprised of 4 different meshes. When it came to mounting the combination as a single payload, I couldn't figure out what to put for the mesh name.

I'll continue to tinker with it and i'll get back to you if I have something to report.

I might try putting the command module as the mesh, and then altering the parameters in the scenario file to get the desired result. It might work, or it might not work. To quote Jim Carrey from The Grinch, "But that's what these tests are for!"

---------- Post added 10-21-15 at 12:09 AM ---------- Previous post was 10-20-15 at 10:53 PM ----------

Update:

I was successful.

I short-fueled the CSM so that it would weigh the same as the Apollo 7 CSM. The Saturn IB was not capable of orbiting a fully loaded CSM.

 

[fred18]

Greate job!

Don't know if it is useful but ms2015 support up to 5 meshes per payload!

 

[1987VCRProductions]

I could make a multistage Saturn V for AAPO as well. The Multistage Saturn IB, however, is up there with one of my favorite things that I've ever made. I just made an ini file for the Saturn IB for use with the LC-39 Milkstool. Pictures to follow.

---------- Post added at 05:21 AM ---------- Previous post was at 05:14 AM ----------

Skylab 4 on Pad 39B:

The subsequent launch of Skylab 4:

I guess I could simulate ASTP as well. I'm having way too much fun with this.

 

[4throck]

Load the scenario with just live=1, close simulation and go edit the current state scenario. If this is not enough,i'll post a more detailed procedure

It's enough. For future reference, it works with Multistage payload name = vessel name. On the scenario, the vessel is attached to multistage.

 

[romanasul]

boogabooga, i really enjoy your AtlasV 421, any chance of making the other variants?

 

[fred18]

It's enough. For future reference, it works with Multistage payload name = vessel name. On the scenario, the vessel is attached to multistage.

yep: the vessel name is the check that is performed when scenario is reloading in order not to recreate again the payload vessel.

I'll prepare a documentation section relevant to this anyway :thumbup:

 

[4throck]

For things like that example scenarios work great ;-)

 

[romanasul]

I just did a flight with the Ariane 5 ECA by well and no matter and it seems the second stage does not play well with the Complex flight activated. After first stage separation when the second stage ignites it flies into infinity. Disabling the Complex parameter before staging fixes it though. Also, is it possible to throttle down the boosters to prevent high G?

 

[fred18]

I just did a flight with the Ariane 5 ECA by well and no matter and it seems the second stage does not play well with the Complex flight activated. After first stage separation when the second stage ignites it flies into infinity. Disabling the Complex parameter before staging fixes it though.

I am currently working on the control loop to make it way more reliable and stable for complex flight, for low FPS and for time acceleration (at least 10x).

it's driving me a bit crazy but I'm almost there...

This anyway could possibly not solve the issue: complex flight must be optimized to be flown smoothly. if at second stage ignition the AOA is high and the altitude is not high enough the drag can block the vehicle from getting the correct attitude.
Can you provide details of what's happening? aoa at second stage ignition, altitude etc? maybe the telemetry file (you can save it directly from the mfd)? Thanks!

Also, is it possible to throttle down the boosters to prevent high G?

not the boosters, but main engine yes. You can use Glimit(xx) in the guidance where xx is the number of Gs. Example: 90=Glimit(4.5) avoid the acceleration to go beyond 4.5 Gs from MET=90 secs to MET=340 secs (check is performed for 250 secs). You can also simply use the "engine" call if you wish. Anyway give a look at the docs, this functions are explained. In case you need help, I'm here!

 

[romanasul]

Thanks, I will do another flight with the Ariane 5 and post the telemetry file.

 

[boogabooga]

boogabooga, i really enjoy your AtlasV 421, any chance of making the other variants?

Thank you, but first of all, just to be clear, "my" Atlas V is a Franken-rocket put together with parts from BrianJ's add-ons, who has generously given me permission to use them. All I've really done is to edit the text files. The hard part was setting the initial pitch and altitude steps to get the new guidance routine to run smoothly.

As for the other variants...
Having the full family of Atlas V was my original intent. All of the boosters are there in the ini file with the unused ones simply commented out (. The order that they appear follows the real-life convention. Conceptually, one could simply add or remove boosters as desired.

However, there are two complications so far:
1) Getting the parameters for a smooth guidance routine was much more time consuming that I expected. (But far less so than the old Vinka pitch vs. time methods) I am not sure how different combinations of payload weight and booster will affect the outcome.

2) There is an issue with the Atlas V 431. The third booster mesh clips the pipe. (I'm not sure if the pipe or the booster location that is "wrong") This may not be an issue for most people.

The pipe/booster clipping is not an issue on the Atlas V 500 series mesh, so one could adapt either BrianJ's solar probe Atlas V or my New Horizons launch scenario pack to get the full 500 series.

I am considering an Atlas V mission pack with the following:
1) Geostationary missions for the Atlas V 421 and 401 (TDRS, early WGS, possibly Morelos-3) using these:
[ame="http://www.orbithangar.com/searchid.php?ID=3679"]Commercial Satellites Part 2: Boeing 601[/ame]
[ame="http://www.orbithangar.com/searchid.php?ID=3275"]Commercial Satellites: Part One: The BOEING 702[/ame]

2) My New Horizons launch scenario updated to multistage2015

3) The upcoming Cygnus mission to the ISS.

 

[romanasul]

Thanks boogabooga, I have actually edited the multistage 2 file for changing the payload multiple times and I didn't notice all the boosters. If I just change the fairing diameter and height in order to try to simulate the 5 series would that work or do i need to change the mesh?

 

[boogabooga]

No, the meshes for both the first stage and the fairing are different. You can get the meshes here:
[ame="http://www.orbithangar.com/searchid.php?ID=6473"]Solar Probe[/ame]

 

[romanasul]

Thanks, well you gave me something new to play with.

 

[1987VCRProductions]

I just realized that the Buran Soviet Space Shuttle on Simviation can be loaded on its multistage launcher as a live spacecraft. I could launch stuff into space, with Buran... I can't remember the last time Orbiter has excited me this much. I'm like a 5 year old on Christmas morning, or on their birthday, opening a brand new Nintendo 64.

I used to hate Multistage, now I'm deeply in love with it.

 

[fred18]

Ok gents,

I thank you all for your support again.

Here is an update that I think it is important:

http://www.intech-srl.eu/fred/MS2015-PreRelease.zip

Control loop has been rewrited basically from scratch to improve stability at both low FPS and high time acceleration.

I tested it in tough conditions (forcing orbiter to have just 10FPS) and it worked absolutely fine!

also in my computer ascent was perfectly stable and precise at 10x acceleration, and at 100x was still stable but not super precise. So for testing purposes users can "play" between 10x and 100x to shorten a lot the time of tests. Also this should guarantee smooth working on low end computers.

I also added in the MFD the visual effect in Control Screen of rotational input, I find them nice in d3d9, let's say so and so with inline client. I haven't may ideas on how to implement them differently, but it's purely a taste issue.

This is planned to be the last update on control commands (unless major bugs arise), autopilot etc. I won't add anything else there.

Only thing that I will add now will be the growing particles, so from now on all the new addons that users are willing to make can be tweaked and won't be messed up from future releases.

Cheers!

Fred

 

[K_Jameson]

I could launch stuff into space, with Buran
[...]
I used to hate Multistage, now I'm deeply in love with it.

Ahem. Even with old multistage you can launch a spaceplane with payloads in cargo bay... not alive payloads obviously...

 

[ISProgram]

... not alive payloads obviously...

Payload bays aren't pressurized.

That be said, I should try this like now. I've been waiting for the full release but the praises so far is making me twitch a bit.