OFSS III Project info and discussion.

jangofett287

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When I made my estimate, I forgot a small factor (minecraft). Sorry about that. However, I today learned that due to Industrial Action in the UK public sector, my school will be closed next Wednesday, so assuming I don't do it before then, I will almost certainly get it done then. Also, is there any good reason why I need to completely disassemble the station and rebuild it this mission?
 

Tex

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When I made my estimate, I forgot a small factor (minecraft). Sorry about that. However, I today learned that due to Industrial Action in the UK public sector, my school will be closed next Wednesday, so assuming I don't do it before then, I will almost certainly get it done then.
No rush! :thumbup:

Also, is there any good reason why I need to completely disassemble the station and rebuild it this mission?
:yes: You are moving the P3P4 solar panels to the top of the station now. Docking clearance for the XR5 in the early missions required P3P4 be docked where they are, but now they need to be moved to the top of OFSS-Core. This unfortunately requires moving many modules and spacecraft around. If you're uncomfortable with it, you could swap flights with someone else who is interested perhaps.
 

jangofett287

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We have a problem. I flew the XR5 up there, attached the P6 truss, and then couldn't retract the Zarya or Zevezda solar panels. I looked. They are both 100% dis-charged. After a couple of orbits, and a lot of wasted RCS fuel, I realized that without the ability to automatically point the station at the sun, I can't charge them up again far enough for there to still be charge after the station has gone round the dark side. Any Advice?
 

Tex

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Please read the 'Problems & Solutions' section in the OFSS-III manual which was included in your package...

Re-deploying Zarya and Zvezda solar panels: After stowing the solar panels on Zarya
and Zvezda during construction, I was unable to re-deploy them in the sim. If you can’t
re-deploy them either, then quit the session and edit the following line shown in bold red
text in your (Current state) scenario for both ‘Zarya’ and ‘Zvezda’:

Code:
Zarya:ISSR\Zarya
STATUS Orbiting Earth
RCSMODE 2
AFCMODE 7
PRPLEVEL 0:0.437277 1:0.410046
DOCKINFO 0:0,Zvezda 1:0,OFSS-Core
NAVFREQ 0 0
XPDR 161
ANT 0 1.0000 -1
CAM 0
[B][COLOR="Red"]SOL_DEP 0 1.0000 -1[/COLOR][/B]
ControlMode 0
SOL_ST 0.0000 0
MSSTATE 1
LIGHT 1 0
BATTERY 621.0657 0.6211
SHOWDATA 0
END
 

jangofett287

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Well regardless, the station juggling is done. I see what I can do about returning that XR5 in one piece.l
 

usmc3891

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Argh..RL gets in the way sometimes lol. Doesn't life know that we have things to do on Orbiter :lol:
 

ADSWNJ

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OFSS III - Go Play in OFSS

Paying homage to Bruce Irving and his excellent Go Play In Space, this is the thread 'for the rest of us' who can fly a DG or an XR ship and can dock at the ISS, and are looking for some pointers to get ahead in this OFSS project.

This project has been a real learning experience for me. Flying in the Russian ships, learning how to fly without translation thrusters, dealing with pulse-mode RCS, using the URMS for the first time ... it's all good. The flight notes are actually pretty obvious in retrospect, but you can burn up hours of effort trying to figure out some of the steps if you don't know a trick or two.

The feeling of satisfaction though is huge. Completing the mission, leaving the OFSS ready for the next flight, and admiring the results is a real kick!

Feel free to post your a-ha moments, your deep learnings and your advice for those who have yet to try these missions. (Put the flight and step into the title to try to keep this thread understandable!).

(With apologies to the pros, who probably do all this and more without having to think about it!)

---------- Post added at 07:56 PM ---------- Previous post was at 07:25 PM ----------

My personal a-ha moment! Although clearly stated in the OFSS flight manual on page 4 (Docking Tips), I cannot understate how important it is to engage the autopilot (e.g. Prograde) on the **target**, as well as on the ship you are flying in.

I've docked many times at the ISS without ever wondering about the alignment or stability of the target. So coming to these instructions (e.g. dock SoyuzTMA to Zarya) - I tried it with just the SoyuzTMA autopilot on, and thought "what's the point of that" when the rotational alignment just drifted off. So I switched off the autopilot and flew the docking by hand. Looking back, it's obvious that if you allow the target ship to drift, it really messes up your alignment, requiring constant adjustments on both translate and rotate.

Moral of the story ... RTFM thoroughly, and switch on both that source and target autopilots in the recommended orientation, and you will be amazed to see a white rotation "X " on the Docking MFD staying rock-steady for the whole docking sequence.
 

Kyle

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Hey all, I'm really sorry I left this project as I'm sure you noticed, but I really haven't had time for Orbiter in general, I'm halfway through my Senior year of HS so rather busy. Keep up the good work!
 

Cras

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Your a-ha moment is one shared by myself as well. Once I found ISS 3.2 which has a CMG, and CMG 2.0 which I have subsequently attached to my own station in LEO, it makes docking by the numbers possible, and much easier workload I must say. I tend to use Attitude MFD pretty much the entire time in orbit, so just a few entries in the velocity mode, and my ship is nice an in line, and all I got to do is keep center needles and bring her in.

Another a-ha moment is the discovery of Rendezvous MFD. I was never to fond of Sync MFD myself, but when I found Rendezvous MFD, it gave me such capability, that I can meet up with a space station, or even something as small as a MTKSSAT! Great fun following the instruments then to finally get a glimpse of the object I have been tracking oh so many miles above the Earth.
 

ADSWNJ

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A couple of visual aides ...

To visually show you the port numbers, use this:
http://orbides.1gb.ru/orbf/dockportshow-080705.zip

(Useful for figuring out the multi-port items like OFSS-Core).

Also basic, but worth knowing ... ExtMFD is your friend. Use it to bring up an MFD that can float over your external view. (E.g. I use Docking MFD in the ExtMFD, so I can get a good panned external view in F1 mode, but still keep things aligned.) One trick with this ... when you need to interact with the main window (e.g. to set the target for docking), then make sure "Focus follows mouse" is set in Parameters on the Orbiter launch dialog. Then you set up your ExtMFD, select the menu (popping up in the main window), move the mouse into the main window WITHOUT CLICKING, then interact with the menu (e.g. arrow keys / return). Basic, I know, but without this, the Ext MFD is fairly useless!

---------- Post added at 12:53 AM ---------- Previous post was at 12:35 AM ----------



URMS ...

Brief info and tips in case you haven't "flown" this yet. You have to select it like you select a ship (e.g. F3). The arm has numerous joints that you can move manually. Highlighting closest object, and grappling closest object (or purge it to ungrapple) moves the arm automatically.

Note that the grapple is more game-mode than realistic. Meaning - you can grapple anywhere on the mesh of the object (e.g. end of a solar panel), and the arm is close to the mesh but not touching. (You need to check to see if you are grappled.)

The arm can fly through objects if you are not careful, especially when auto-grabbing or auto-stowing. No harm to the game, but irritating if you are a perfectionist :).

On Flight #2 ... note that the Cupola is the dome shape (i.e. it's a viewing room), and the OFSS-Dock1 is the dock mating adapter (a slanting tube like a tumble dryer exhaust tube!).

An example use of the URMS ... Flight #4 step 3, undocking and grappling Soyuz. Swing your arm round to get really close to the Soyuz. Switch on target mode to make sure you are targeting the Soyuz. It'll be red, because you can't grapple it whilst it's still docked to the OFSS Core. F3/switch to Soyuz, then Ctrl-D to undock. Switch back to the URMS, and the Soyuz will now be green and moving back from the OFSS-Core. Quickly grapple it and you are good to go.

(Optionally, you can null out the undock motion first (fwd thrust on Soyuz), but I figure that you have pushed off from the OFSS, so grabbing it in motion should end up with a zero net momentum, versus nulling and then grabbing!).
 

RisingFury

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Still waiting for jangofett to finish his mission. :shrug:
I don't really want to get involved with this and it may have come late, but you might wanna assign more than one person for every mission. The first one that returns the scenario is considered the pilot for that mission.

If you're worried about one person quickly flying every mission, you could set caps on how many or how frequently every person flies missions.
 

Tex

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I don't really want to get involved with this and it may have come late, but you might wanna assign more than one person for every mission. The first one that returns the scenario is considered the pilot for that mission.

If you're worried about one person quickly flying every mission, you could set caps on how many or how frequently every person flies missions.
I plan to announce a time limit from now on. 2 weeks should be ample time to complete the mission, perhaps even 1.
 

ADSWNJ

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Flight 5 thoughts ...

Step 1 ... try to do a reference ascent per the XR Flight Ops Manual. I.e. take off, roll to the heading, 70 degree bank, level off at 24km, build up to Mach 4.5 then blast your SCRAMs right up to Mach 18+. I targeted 200km for the main engine cut-off, to keep some advantage on the OFSS (i.e. less orbit time, so I can catch it up), then circularized it at the Apogee to have a 200kmx200km orbit.

Step 2 ... Align Planes with the OFSS as usual, then Sync Orbits. I chose a Self-Apogee rendezvous to keep the burn as low as possible. Let it roll down to 3 or 4 orbits to go, then raise the Apogee (at the Perigee). Let it come back again to 1-2 to go, then zero out the DTmin at the Apogee point. For the final rendezvous, switch to the OFSS-Core and set prograde autopilot (ahem!!), then do a quick prograde on the XR-5 before taking her in manually for the dock.

Step 3 ... Another a-ha moment here. "Gently nudge the obital inclination to 51.60" means to set it to 51.60 degrees from the Equator. The default Align Planes and Orbit MFD is referenced to the Ecliptic (i.e. the sun-planet plane, not the Equator). Flipping FRM on Orbit MFD shows the difference in the Inc's ... i.e. we start at 51.65 EQU / 42.44 ECL, and we want to roll back 0.05 to 51.60 EQU / 42.39 ECL. Not strictly necessary, but I used Align Planes with a manual target (i.e. 42.39 and 181 or whatever the LAN was). To nudge it, I rolled Prograde and used the hover engine ever so gently on the DN. (Do Retrograde and Hover on the AN if you need it). Then I lifted the OFSS to 500.0x500.0 with 4 gentle forward thrusts. A couple of things here ... as you are docked, you have a big mass off the front of the ship, so you need to be careful not to over-power the engines. If you do, the RCS thrusters will not be able to keep alignment and you will end up in a spin!

Step 4, 5, 6 ... Eranda is the big cylinder module, QuestFin the airlock that looks like an engine, and Soyuz-Dock looks like a simple puck-like dock. Getting the pieces grappled is a case of moving the URMS into "green" range (highlight nearest object), then swinging it round to the right port. The tricky thing is to get the right rotation on the object prior to placement. I switched to the docking view of the component (e.g. into Eranda), whilst moving the URMS wrist to get the right alignment. Once I was within 5-10m, I ungrappled, switched to the XR-5 and used translation thrusters to move the ship to the piece. (Couldn't figure out how to manipulate the arm to do it without thrusters, but it all worked out in the end, so hey!)

Step 7 ... I used BaseSync and Aerobrake to get back to KSC. 43 degrees anticipation, 0.4 degrees reentry angle and 80KM reference alt. I struggled a bit with range, and had to dip the nose to around 35 degrees to keep enough energy, then used a bit of thrust at the end to roll out on KSC RWY 15. Great mission!

---------- Post added 01-03-12 at 01:01 PM ---------- Previous post was 01-02-12 at 07:16 PM ----------

I plan to announce a time limit from now on. 2 weeks should be ample time to complete the mission, perhaps even 1.
If you need to build a reserve roster, then I'd be interested to be on standby for a mission.
 

Tex

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If you need to build a reserve roster, then I'd be interested to be on standby for a mission.
Thanks for letting me know. If I don't hear from the upcoming pilot in a reasonable amount of time, I'll ask you to replace them. :thumbup:
 

ADSWNJ

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Just finished the simulator run for flight #14 (post-flight scenraio available if needed for the main flight). A couple of flight notes ...

1. You have a 25km difference PeA to ApA, so it's definitely worth synchronizing AgP before coming in to dock (so you have less drift to worry about on your final docking run). Nudge your mains or retros in prograde mode at TrA = 90 or 270 degrees (i.e. right angles to the Apo/Peri) to bring AgP round to match the ISS.

2. You need to use URMS3 to pick up the two modules, but it's not super-long. I found you have to do step 4 (RecMod attach) first, or the URMS3 fouls on the docked HabModule4 from step 3.

I still can't get the hang of completeing the final alignment of the modules onto the target docking ring just using the URMS. As a compromise, I get it as close as possible, and well aligned rotationally, then purge it from the arm and nudge the XR5 to finish the mating. (Does anyone have some hints how to do this better?)

Anyway - a simple flight and back home again in just over 3 days.
 

NovaSilisko

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(hopefully this is the right place to put this)

Once I get my Everest launch vehicle operational, I would like to launch two MPOD-Vs (MPOD-V2 Plato, and MPOD-V5 Aristotle) and a Station Core Module to make a part of the station. Would this be okay?

(I still need to learn how to rendezvous properly so it's not any time soon)
 

ADSWNJ

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What's the latest status on OFSS? Are we at a programmed hold on Flight #16?
 
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