Orbiter-Forum  

Go Back   Orbiter-Forum > Orbiter Addons > Addon Support & Bugs > Addon Developer Forums > Space Shuttle Ultra
Register Blogs Orbinauts List Social Groups FAQ Projects Mark Forums Read

Space Shuttle Ultra Support & development threads for Space Shuttle Ultra addon.

Reply
 
Thread Tools
Old 09-20-2019, 03:40 PM   #1
knight7173
Orbinaut
Default SSU Tutorials

Good Afternoon Everyone

I have sucessfully Launched, stabalized oribit (OMS Burns) and got RInc to 0 and adjusted orbit height and velocity etc by following the tutorial in the attached link. Many thanks for that BTW

https://www.orbiter-forum.com/showthread.php?t=39599

I was wondering if there was any tutorials for how to conduct Deorbit/Reentry and landing etc.

I have looked through the forum and havent seen anything definitive.

I have also looked through the Nasa SOCM and other detailed manuals but unfortuantly they just go over my head.

I understand how to use the GPC and shuttle systems I just think it is the way the forms out there are presented. I know that SSU is designed to be realistic as possible and I absolutely love it I am just so keen so see it from start to finish

I apologise if this has been mentioned and resolved before and I have just missed it. any help is greatly appreciated.

Kind regards

Guy
knight7173 is offline   Reply With Quote
Old 09-20-2019, 04:11 PM   #2
GLS
Addon Developer
 
GLS's Avatar
Default

Quote:
Originally Posted by knight7173 View Post
 Good Afternoon Everyone

I have sucessfully Launched, stabalized oribit (OMS Burns) and got RInc to 0 and adjusted orbit height and velocity etc by following the tutorial in the attached link. Many thanks for that BTW

https://www.orbiter-forum.com/showthread.php?t=39599

I was wondering if there was any tutorials for how to conduct Deorbit/Reentry and landing etc.

I have looked through the forum and havent seen anything definitive.

I have also looked through the Nasa SOCM and other detailed manuals but unfortuantly they just go over my head.

I understand how to use the GPC and shuttle systems I just think it is the way the forms out there are presented. I know that SSU is designed to be realistic as possible and I absolutely love it I am just so keen so see it from start to finish

I apologise if this has been mentioned and resolved before and I have just missed it. any help is greatly appreciated.

Kind regards

Guy
Yeah, that's probably the biggest hole in the flight: the deorbit burn.
I haven't looked in detail, but I'm pretty sure the GPCs alone can't determine the burn, so something else must generate the data. In real life MCC had a tool, with a similar "feel" to the MFD FDO by indy91, but for generating deorbit burns to hit the entry corridor just right, but I don't think ATM there is enough info to make that tool.
I was thinking of creating a stop-gap deorbit burn "search engine", just to "throw" the vehicle in the general direction of the runway... but I'm not really motivated at the moment...

For now the only way is trial-and-error.
GLS is offline   Reply With Quote
Old 09-20-2019, 06:11 PM   #3
indy91
Addon Developer
Default

Quote:
Originally Posted by GLS View Post
 Yeah, that's probably the biggest hole in the flight: the deorbit burn.
I haven't looked in detail, but I'm pretty sure the GPCs alone can't determine the burn, so something else must generate the data. In real life MCC had a tool, with a similar "feel" to the MFD FDO by indy91, but for generating deorbit burns to hit the entry corridor just right, but I don't think ATM there is enough info to make that tool.
I was thinking of creating a stop-gap deorbit burn "search engine", just to "throw" the vehicle in the general direction of the runway... but I'm not really motivated at the moment...

For now the only way is trial-and-error.
There is 330 pages of deorbit targeting equations in one of the Shuttle Flight Design System documents. I'll implement that in the Shuttle FDO MFD... eventually.
indy91 is offline   Reply With Quote
Thanked by:
Old 09-20-2019, 09:12 PM   #4
knight7173
Orbinaut
Default

I know I have seen a video on youtube of a de orbit burn etc done on columbia SSU someone was simulating STS-1 but unfortuantly the video was just that didnt have any commentary or voice input as to what they were doing just have to trial and error for now I guess thanks anyway gents
knight7173 is offline   Reply With Quote
Old 09-20-2019, 09:36 PM   #5
Urwumpe
Not funny anymore
 
Urwumpe's Avatar

Default

Calculating the optimal deorbit burn is a rather complex optimization problem, having a MFD to calculate a series of deorbit burn parameters would be a good start.

I could maybe create a tool to calculate such a set from a saved scenario, but I can't do a MFD right now... All I have is Intel Graphics right now.
Urwumpe is offline   Reply With Quote
Old 09-20-2019, 09:57 PM   #6
GLS
Addon Developer
 
GLS's Avatar
Default

Quote:
Originally Posted by Urwumpe View Post
 Calculating the optimal deorbit burn is a rather complex optimization problem, having a MFD to calculate a series of deorbit burn parameters would be a good start.

I could maybe create a tool to calculate such a set from a saved scenario, but I can't do a MFD right now... All I have is Intel Graphics right now.
Even a command line tool would be enough.
IMO there are 2 parts to this problem: (1) getting a safe gamma at EI, which is determined by the post-deorbit burn perigee and apogee (easy for circular, maybe a PITA if not), and (2) at what range (and crossrange) from the runway is EI, which is determined by TIG.
So taking the orbital data and propagating it between 2 times, with some dT each step, one could calculate a series of solutions, and then select what is valid and give that to the user. Even with loads of assumptions and simplifications, such a tool should be much superior to what we have now, i.e., nothing.
I can make the MFD graphics if you make the logic above...
GLS is offline   Reply With Quote
Old 09-21-2019, 05:19 PM   #7
Thorsten
Orbinaut
 
Thorsten's Avatar
Default

If a commandline tool is enough, may I recommend LEO targeting?

It actually can optimize given a PEG-4 constraint for the entry interface and the desired range - among other things, I wrote the tool for precisely that purpose.

And it's GPL licensed, so you can modify it to your needs...

(In practice, the Shuttle can't really reach high eccentricity orbits, so usually pocket formulae get you well into the cross range and optimizing the last 20 miles of range out of the problem might not be really necessary... but there's exceptions to that).

Last edited by Thorsten; 09-21-2019 at 05:22 PM.
Thorsten is offline   Reply With Quote
Old 09-22-2019, 06:16 PM   #8
Gingin
Orbinaut
 
Gingin's Avatar
Default

Hey knight.

Starting from an almost circular orbir, target the burn 180 from the landing site to create a Perigee above it.
You can assess that with Map Mfd or with Base Sync MFD ( which will give you crossrange also)

Then intensity.
Aim is a perigee of 20 Nm
Current Perigee - 20 Nm and times 1.8 for a good first approximation of Dx intensity

That works really well and will give you a good entry interface , 4000 Nm ish at 400 kfeet with a coherent flight path angle



For PEG 4 targeting and PEG 7 conversion ( including a radial burn eventually, hard to determine by hand), Thorsten's Tool works like a charm.
Gingin is offline   Reply With Quote
Old 09-23-2019, 07:09 PM   #9
knight7173
Orbinaut
Default

Thank you for your feedback,

I will continue to try to make it back to earth

I have a Orbiter 2010 build with AutoFCS.

I know it is classed as cheating compared to the detailed GPC etc of the SSU but would it work in Orbiter 2016? least that way can get back down to KSC etc
knight7173 is offline   Reply With Quote
Old 09-23-2019, 07:22 PM   #10
DaveS
Addon Developer
 
DaveS's Avatar


Default

Quote:
Originally Posted by knight7173 View Post
 Thank you for your feedback,

I will continue to try to make it back to earth

I have a Orbiter 2010 build with AutoFCS.

I know it is classed as cheating compared to the detailed GPC etc of the SSU but would it work in Orbiter 2016? least that way can get back down to KSC etc
SSU already has the Aerojet DAP implemented. It becomes active once you're in MM304. It will take you through entry and landing (yes, itl can do autoland). The only thing really missing is of course the de-orbit calculations. But really, everything that's done onboard (except for the FRCS dump) is implemented. There's no need for anything external.
DaveS is offline   Reply With Quote
Old 09-24-2019, 06:56 AM   #11
Gingin
Orbinaut
 
Gingin's Avatar
Default

Quote:
Originally Posted by knight7173 View Post
 Thank you for your feedback,

I will continue to try to make it back to earth

I have a Orbiter 2010 build with AutoFCS.

I know it is classed as cheating compared to the detailed GPC etc of the SSU but would it work in Orbiter 2016? least that way can get back down to KSC etc
Autofocus will.not work and like said Dave will be useless compared to the coded entry dap in ssu 1000 times stronger.
Try what I suggested for the deorbit burn , quick and easy way for spot on entry interface


Using external mfd / tools is not cheating,
See that like a mission control center where 50 guys with dozens of computer and algorithms were helping the 2 pilots in the Shuttle and lost without MCC
Gingin is offline   Reply With Quote
Old 09-24-2019, 09:20 AM   #12
Urwumpe
Not funny anymore
 
Urwumpe's Avatar

Default

Quote:
Originally Posted by Thorsten View Post
 If a commandline tool is enough, may I recommend LEO targeting?

It actually can optimize given a PEG-4 constraint for the entry interface and the desired range - among other things, I wrote the tool for precisely that purpose.

And it's GPL licensed, so you can modify it to your needs...

(In practice, the Shuttle can't really reach high eccentricity orbits, so usually pocket formulae get you well into the cross range and optimizing the last 20 miles of range out of the problem might not be really necessary... but there's exceptions to that).
Did you have an example for that? And can you also allow burning off-target to dump excessive aft propellant mass in the solution?
Urwumpe is offline   Reply With Quote
Old 09-24-2019, 10:17 AM   #13
Wolf
Donator
 
Wolf's Avatar
Default

Quote:
Originally Posted by Gingin View Post
 Hey knight.

Starting from an almost circular orbir, target the burn 180 from the landing site to create a Perigee above it.
You can assess that with Map Mfd or with Base Sync MFD ( which will give you crossrange also)

Then intensity.
Aim is a perigee of 20 Nm
Current Perigee - 20 Nm and times 1.8 for a good first approximation of Dx intensity

That works really well and will give you a good entry interface , 4000 Nm ish at 400 kfeet with a coherent flight path angle



For PEG 4 targeting and PEG 7 conversion ( including a radial burn eventually, hard to determine by hand), Thorsten's Tool works like a charm.

Hi Gingin,


could you be more specific on the procedure you follow and the tools (MFDs) you use, maybe a practical example?
Wolf is offline   Reply With Quote
Old 09-24-2019, 02:12 PM   #14
Snax
Space Cowboy
 
Snax's Avatar
Default

Hi, if I can be of help, here's how I do it with BaseSync MFD for the Deorbit burn.

Deorbit burn preparations
  1. With OPS201 I tell the Shuttle orbiter to be in retrograde (+ or - 15 degrees for the SSMEs):
    1. ITEM14+5 (body reference)
    2. ITEM15+75 (90 for retrograde position minus 15 for SSMEs)
    3. ITEM16+0
    4. ITEM17+0 ENTR
    5. 19 ENTR (the Shuttle will be in retrograde and heads down, you can do 105, 0, 180, to be heads up)
      (you can type as follows: ITEM14+5+75+0+0+ENTR all at once)
    6. DAP in AUTO
  2. Then in OPS202: I enter a huge value in PEG7 in ITEM19 (eg: ITEM19-500 ENTR), Make sure ITEM20 and ITEM21 are nulled. This will give me so much negative DeltaV so I can stop it by shutting down the OMS by hand on the C3 panel.
  3. For the TIG I enter any value that is before the MET so the GPC will believe it's time to burn and tell you to initiate the burn by pressing ENTR again (you'll just need to press ENTR when you want to that way)
  4. Don't use ITEM27 for this "technique", just ITEM22 and ITEM23, you already set your retrograde position.
  5. And now wait until BaseSync tells to, basically when DeltaV reaches 0 in that MFD, you'll need to configure BaseSync for the reentry:
    1. ANG: 1.23 (angle of penetration of the atmosphere)
    2. ANT: 74,48 (don't remember what this value is)
    3. ALT: 121,92km (wich is 400'000ft)
    (here's a turotial for BaseSync by the great David Courtney)

Then for the reentry parameters
  1. with OPS201 I type:
    1. ITEM14+5 (body reference)
    2. ITEM15+230 (pitch +40)
    3. ITEM16+0
    4. ITEM17+0 ENTR
    5. ITEM19 ENTR (to initiate the tracking)
    6. DAP in AUTO
  2. Then I switch to MM303 (OPS303) and wait the TFF to reach 0, a few minutes before to that (~5mins), I start the APUs.
  3. I switch the DAP to LVLH to maintain my 40 pitch of attitude just in case
  4. MM304 when TFF is 0 (Time For Four hundred thousand feet)

I know it's not realistic but it gets the job done when you just want a quick ride in orbit. It works every time.


__________________________________________________ _____

Here's a video how I do it (FYI, I talk in french to my viewers).


Timestamps
22:45: OPS201 for retrograde position
28:20: retrograde burn initiated
29:46: OPS201 for 40 AoA for the reentry
30:50: OPS303 then SPEC50 for the horiz sit then ITEM4 for KSC RWY33
32:57: APU start
33:54: OPS304 (i forgot to click RESUME to revert the screen to the graph)
37:15: Data Air Probles deployed (below Mach 5) and HUD set to ON, will be live after TRAJ5 in the CRT3
38:20: HUD is live
39:14: going CSS (control stick steering) at Mach 0.95

Last edited by Snax; 09-24-2019 at 03:53 PM. Reason: Is it readable with colours ?
Snax is offline   Reply With Quote
Thanked by:
Old 09-24-2019, 03:19 PM   #15
kuddel
Donator
Default

del'd

Last edited by kuddel; 09-24-2019 at 03:28 PM.
kuddel is offline   Reply With Quote
Reply

  Orbiter-Forum > Orbiter Addons > Addon Support & Bugs > Addon Developer Forums > Space Shuttle Ultra


Thread Tools

Posting Rules
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
Forum Jump


All times are GMT. The time now is 06:28 AM.

Quick Links Need Help?


About Us | Rules & Guidelines | TOS Policy | Privacy Policy

Orbiter-Forum is hosted at Orbithangar.com
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 2007 - 2017, Orbiter-Forum.com. All rights reserved.