Tutorial Tutorial Development On Orbiter 2016 Stock Space Shuttle ISS to KSC Ballistic Re-entry Case Study Project -v1.0

[polaris149Tiberius]

Tutorial Development On Orbiter 2016 Stock Space Shuttle ISS to KSC Ballistic Re-entry Case Study Project -v1.0




This will be a case study of how to de-orbit the Orbiter 2016 stock Space Shuttle from Low Earth Orbit (LEO) into a single ballistic entry interface and re-entry that puts the STS-101 Orbiter within 10nmi of the Cape for HAC and landing on runway 33 or 15. Any notes, developed procedures, and findings will be posted in this thread until the final process is documented and ready to be published as a tutorial PDF to be placed in the Orbiter Downloads/Orbiter Addon/Public/Tutorials section of these forums. Wish me luck.

After attempting to follow several different pre-existing online tutorials on how to de-orbit burn and reenter the atmosphere to land at KSC safely and within some of the structural limitations of what the real Space Shuttle can do in such a highly dangerous process, I have found that there are almost 0 tutorials or much information on how to reenter and land for the stock Space Shuttle for Orbiter 2016 v.160828. Most of what I found was for the DG or other addon vehicles but very little for the stock Space Shuttle. Nearly none of them incorporate the signature 40* angle of attack (AoA) entry or the "EI -5 attitude" that the Orbiter's re-entry is most notable for.

The stock Space Shuttle is (I believe) Orbiter's signature vehicle aside from the Delta Glider. With the DG being fictional, I thought it might be worth my time to devise a procedure for newcomers to use the basic Orbiter default Space Transport System (STS) -101 to help with the process of making the features of Orbiter (with little effort) achievable in many of the processes that the Space Shuttle is known for (i.e. launch to orbit, rendezvous and docking with the ISS, de-orbit, re-entry and landing at KSC).

I will post the entire process of my own study and it's results in a sort of "captain's log" format so other Orbinaughts can follow along and see how the more relevant end results are achieved.

The whole process is relatively simple. At a little closer than the opposite side of the orbit (at Dst 17.76M) that takes us closest to KSC, we will burn retrograde until our orbit's PeA is 0.00km. It puts us on a low G-force (about 3Gs) entry angle that if we hold an AoA of about 1.1 using Orbiter's default PRO GRD until 96km altitude, then HORZ LVL we should be at about Mach 10 when you get around 100 km from KSC.

I will begin with some known bits of information:

1. The original scenario used to begin the de-orbit, re-entry, and landing processes will be taken from an original Orbiter 2016 scenario provided with the installation which is normally used as a playback tutorial that I have edited out the playback function for a launch scenario called "Space Shuttle to ISS.scn".
2. I will provide the launch scenario ("Space Shuttle to ISS-0005-0005-Launch.scn" that can be used to start from the beginning of the mission as well as the "starter" scenario for this study/tutorial ("Space Shuttle to ISS-0005-0045-Tutorial Start.scn") as well as scenarios at various key points in the study's progress to demonstrate the process.
3. The tutorial aspect of this study will cover from a time after undocking from the ISS starting at about .25 orbits before de-orbit burn, a de-orbit burn, re-entry, and an initial approach of about 50km from Kennedy Space Center (KSC) aka Cape Canaveral or "the Cape" .
4. STS-101 will undock with only 8.49 (8,493)kg of propellant transferred from docking collar with the ISS using rstarkov's ReFuelMFD-v003 otherwise we would not have enough fuel to de-orbit burn.
5. The example "starter" scenario will occur at .75 orbits prior to the closest pass over KSC to use for this procedure/case study.
6. The de-orbit burn for this study/tutorial will be made on the orbit #1 listed in ADSWNJ's wonderful BaseSyncMFD 3.3 for Orbiter 2016 at .5 orbits prior to the closest approach to KSC.
7. All results will be posted here in a format easy to read and understand describing all maneuvers and results in order for anyone to re-create.
8. This study/tutorial is using this version of Orbiter: Orbiter 2016 v.160828
9. The only other two addon MFDs used either for monitoring or adjusting the re-entry and landing procedures are: Glideslope 2.7 for Orbiter 2016 by ADSWNJ, and AeroBrakeMFD by gp (for Orbiter 2010 P1 but works for Orbiter 2016)
10. This study and tutorial in no way makes the claim that this re-entry process is realistic in any way. In fact it is well known that a 0.1 AoA re-entry would rip the wings off the Space Shuttle so this type of ballistic re-entry is only designed for ease and for the beginner Orbinaught who wishes to experience an easy re-entry without any realism and with minimal effort.

The first step in this project is to start from the same place using the same situation that this tutorial will follow. In this case it is my Orbiter scenario:

1. Space Shuttle to ISS-0005-0045-Tutorial Start.scn

It should be noted that this scenario was generated from the original version of "Space Shuttle to ISS.scn" and edited for this tutorial and was created by launching to LEO, rendezvoused with the ISS, docked with the ISS, transferred fuel, undocked and purged of it's cargo, and fast forwarded to this re-entry window of opportunity naturally.
The launch scenario is provided in the downloadable package and is called "Space Shuttle to ISS-0005-0005-Launch.scn".


We will start with this scenario (Space Shuttle to ISS-0005-0045-Tutorial Start.scn) so that all other procedures in this work will be re-creatable on your own simulator. And following all the steps will likely provide the same results so you can continue and achieve landing at KSC.

Space Shuttle to ISS-0005-0045-Tutorial Start.scn: puts you at about 17.20M (M stands for Megameter (Mm): 1 Mm = 1,000 km) so we are essentially 1720,000 km from KSC at this save point (the beginning of this scenario). Other notable information is that we are at 364.6k (k = kilometers) above the Earth's surface. This amount can be handy if we ever work on other entry interface procedures and processes. Our velocity is 7.693km/s. The seconds part is important because we need to know that we are traveling very fast and this is the orbital velocity we need to stay in orbit.

Today we will be lowering this velocity to intersect the Earth's atmosphere very soon and may need to know how much delta V (∆v or change in velocity +/-) we will need to bring our Periapsis (the lowest point of our orbit) down. This is done with a retrograde burn.

We have to remember that in Orbiter 2016, the stock Space Shuttle uses its Orbital Maneuvering System (OMS) engines to perform various orbital maneuvers. These engines are at a +15° from the X axis of the Shuttle's nose to tail. You must pitch +15° in the retrograde direction in Orbiter attitude to fire them and for them to do their job. This can be done using the stock MFD: RCS Attitude MFD already provided in Orbiter 2016 for this exact maneuver.

So after starting the scenario provided, you will need three main MFDs for this maneuver. OrbitMFD, RCS Attitude, and MapMFD. We will use MapMFD to see when to fire our OMS engines at less than 1/2 an orbit away from this closest passage to the KSC. We will use OrbitMFD to see our periapsis altitude (PeA) and we will use RCS Attitude MFD to pitch up to +15° in the retrograde direction for the burn.
So here are the steps:

1. If your scenario is paused, un-pause it and set your time compression to 0.1x by pressing "R". You will notice that your time is about Thu Mar 25 10:35 2010 UTC a mere 46.5 hours after launch. This is unrealistic but serves our purposes for learning this process. Your MET will show 46:37:23 or so. Do not worry if these numbers are not exact.
2. Open an external MFD (F4, "function" menu), External MFD, then click "SEL" at the bottom and until you see Attitude RCS on the list. Click the button ">" next to that MFD to open it up. This is how you will choose all your MFDs from here on.
3. Once it opens, click the SET button to select prograde. Then click the INV button so it shows "retrograde". Now click the +R button to add a + pitch amount and then click +V button until it reads "+15". Do not press GO yet. We need to save all the fuel we can.
4. Note our fuel. We have 8.49 (8,493)kg of propellant. More than enough to get us home safely.
5. Now open another External MFD and it should default to Orbit MFD. Set it up to see your PeA by pressing FRM until you see "Frm EQU" in the top right corner, then PRJ until you see "Prj SHP" up there as well. Next press DST button until you see the OSC. EL. info show the PeR change to PeA. Note your PeA amount. It should be around 360.9k (kilometers). We haven't de-orbit burned yet.
6. Now note in your Right MFD (R-MFD) that it is already set to MapMFD. Note in the white text there is a distance for the Cape labeled "Dst. 17.62M" or so. The number should be going up which means we are getting closer to KSC. We will watch this amount coming up very closely for the farthest point from KSC and then our point soon after for the beginning of our burn.
7. For now we will look for the beginning of the furthest distance to KSC which should be about 19.44M.
8. Speed up your simulation time compression to 1x by pressing "T" once. You will not see any time compression listed in the top right of your screen as you do when it is anything other than 1x.
9. If you are good at time compression you can fast forward at about x10 until you see 19.44M in the MapMFD for distance to Cape Canaveral.
10. You will watch the 1/2 orbit to KSC come and go. Once you pass this point up in your orbit the numbers will start to go back down again. We are still getting closer to KSC.
11. After passing the furthest point from KSC, and at distance to BSE: Cape Canaveral 18.20M press the GO in RCS Attitude MFD to begin the pitch to retrograde +15°. Let it hold you there until you see Dst 17.76M.
12. The second it goes to 17.76M you will engage your full throttle of your OMS engines using the + key on your numpad and then press the left Ctrl button afterwards to keep it on. Be ready to cut your throttle with the numpad * key next.
13. In OrbitMFD (which you must watch closely now) you will wait until you see your PeA drop to 0.00k. When it does, cut your engines. If you are good at time compression in Orbiter, again you can slow down the cutoff moment when your PeA gets close to 0.00k to get it exactly on this altitude as it will make a bit of difference on how close you get to KSC when you transition to atmospheric glider flight for landing on runway 15 at KSC.
14. The main thing is to get the PeA close to 0km for this burn. The burn should be about 00:03:56.69 (=236.69 seconds). I have also timed the burn at about 00:03:57.34 minute burn (237.34 seconds), so somewhere between those timings. You can use Timer MFD v1.0 by BEEP (which works with Orbiter 2016) to start your timed burn and end at a predictable PeA of 0.00k or close to it.
15. After cutoff you can stop your RCS Attitude MFD holding retrograde +15° by pressing the RTN button then END.
16. Your fuel should be about 3.57kg.
17. Now you can use the default Orbiter PRO GRD autopilot to point and hold prograde attitude until entry interface which is about 96km altitude. This will hold roughly a -1.6° to -3.0° AoA until the entry interface.
18. Switch your Orbit MFD to Surface MFD for a moment.
19. Select the HUD button in preparation for entry interface.
20. While you wait, you can open your Glideslope v2.7 MFD and your BaseSync v3.3 MFD as well as your AeroBrakeMFD to keep an eye on things, see your entry predictions and be ready to use Glideslope to glide to KSC's HAC and land on rwy 15/33.
21. After PRO GRD you will be waiting approximately 00:27:47.00 (1667 seconds) you should pass 100km altitude. You can set a timer for this to get ready for the next few steps.
22. At 00:28:06.50 (1686 seconds) you should get to 96.00km altitude.
23. At EXACTLY 96.00 km altitude you will then activate the default Orbiter HORZ LVL autopilot. This will keep you at roughly a 1.1 AoA for the re-entry phase. You must hold PRO GRD until this altitude and hold it until the moment you see your altimeter change to 96km or the ballistic re-entry corridor will not put you at KSC's Terminal Area Energy Management phase and approach to the Heading Alignment Cylinder for landing.
24. Once you have turned right side up you will watch for your altitude to pass 76.00km and turn off your RCS jets by selecting OFF in the top left side of your screen, then roll to about 45° to 50° left or counter clock-wise.
25. This is where the action starts!!
26. When you have done that, press Bnk in AeroBrakeMFD to hold this bank turn. Then you will need to set up AeroBrakeMFD to allow you to see where your path will take you to know when you can turn off this bank turn.
27. You may need to hold this bank manually as well to keep your turn going. AeroBrakeMFD is not that good at holding this bank for you.
28. You should be holding about a 1.1 to 1.5 AoA as seen in your Surface MFD. The HORZ LVL is STILL ON as you have not turned it off per these instructions yet...
29. Set your AeroBrakeMFD to view the map and your base cross hairs for KCS. Try to keep your dotted green line on top of the center of that square in the top left. It may look like you will not reach KSC at times on both this map and your MapMFD but keep going and the orbit will extend to some degree.
30. When you see your path cross the center of AeroBrakeMFD's display you can kind of null your roll rate back to level.
31. When you get to about 643km distance you can press F9 to see the displays but make sure that Surface bases is checked to on in the Visual helpers menu found in the F4 Orbit menu under "display" menu.
32. Once you see Cape Canaveral, you can aim towards the left of it using just your roll while maintaining the HORZ LVL. You want to be to the left of the Cape to land on runway 15. If you set up Glideslope CFG you can select this runway and when you get close you can use the AUT autopilot to some extent to get onto the glideslope and somewhat follow the HAC down to the runway if you overshoot a bit.

This method is not perfect and it is not by any sense of the word realistic in any way but it gets you down to KSC with some reliability using a ballistic re-entry approach so you can start practicing landing and having fun. I hope this simple tutorial helps and discussion is ALWAYS welcome. I have attached some scenarios that you can drop into your Orbiter/Scenarios folder if you need some help to follow along. Good luck and Enjoy!!







... in progress