OHM CRS-14 Launch Scenario

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Author: brianj

A launch scenario for CRS-14 mission and associated .cfg file for Falcon9.
Scenario starts ~15mins before lift-off time of 20:30:41 UTC, 02 April 2018.
ISS with Canadarm is in orbit (vectors from JPL Horizons).
Dragon recovery vessel is on station in Pacific.
"CRS-14 Launch" scenario is in "Cargo Dragon for Orbiter2016" folder on the Orbiter launchpad selection.

 

REQUIRED ADD-ONS

"Cargo Dragon for Orbiter2016" add-on
https://www.orbithangar.com/searchid.php?ID=7092

"Falcon9 for Orbiter2016" add-on
https://www.orbithangar.com/searchid.php?ID=7091

"Canadarm2v4.0" add-on
https://www.orbithangar.com/searchid.php?ID=6883

"SSRMSD.dll update" add-on
https://www.orbithangar.com/searchid.php?ID=7064
(non-standard installation required - manually place SSRMSD.dll in Orbiter/Modules folder)

 



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fatcat

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Thanks Brian

Luv the SpaceX scenarios.
The new Space Shuttle for me.

The 1st stage flyback for CRS-14 launch has no autopilot selectable or fuel in the Control Panel.
Can we just edit the scenario to include?

Many thanks.:tiphat:
 

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Kyle

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That's because the first stage is not going to be making a landing attempt on this mission.
 

BrianJ

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The 1st stage flyback for CRS-14 launch has no autopilot selectable or fuel in the Control Panel.Can we just edit the scenario to include?
Sure.
You can't enable the Flyback Autopilot unless it has a target.
You can enter a flyback fuel reserve, regardless.
You can use scenario editor to create a new ASDS(select Falcon9R_V12/barge) as a target.

If you want to switch the Falcon9 from "Expendable" mode to "Recoverable" mode, edit /Config/dragon1/f9_v12_crs14.cfg.
Comment out ; the Expendable = 1 line.

Otherwsie you get a passive 1st stage after separation.

Cheers,
BrianJ
 

Zach121k

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The rocket has legs and soot though.... can we have those on the craft
 

pappy2

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Hello "brian"
I'm sorry, but it seems from the first pictures of CRS-14 that despite the 1st floor is not recovered, the booster has kept the gates and landing gear.

Great job, thanks again.






https://twitter.com/TheFavoritist
 
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BrianJ

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The rocket has legs and soot though.... can we have those on the craft

Hello "brian"
I'm sorry, but it seems from the first pictures of CRS-14 that despite the 1st floor is not recovered, the booster has kept the gates and landing gear.
Hi,
yes, looks like a recycled interstage section too (different to last time I think).

Anyway, if you want "legs" then disable "Expendable" mode:
Edit /Config/dragon1/f9_v12_crs14.cfg
Delete or comment out (put a ; at the start of the line) Expendable = 1

Charred = 1 should already be enabled ("soot" does not extend to interstage though)

Cheers,
BrianJ
 
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Zach121k

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i wonder if an expendable with legs option wouldn't be hard to make
 

Buck Rogers

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Really great Addons! For me the best reason for using Orbiter2016.
One question did arise since the first time I flew the CargoDragon; how/when should the solar panel covers be jettisoned? I would have presumed they'd go on the way up, but when jettisoned on orbit, prograde, wings level, they oscillate along the flight vector and collide with the ship!
Also the recovery ship isn't targetable, where/ what should I target for the de-orbit program?
Otherwise I can't say how one could improve on it, the only wish I would have open, as icing on the cake, would be simulated random engine failure.
 

BrianJ

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One question did arise since the first time I flew the CargoDragon; how/when should the solar panel covers be jettisoned? I would have presumed they'd go on the way up, but when jettisoned on orbit, prograde, wings level, they oscillate along the flight vector and collide with the ship
Hi,
have a look at the SpaceX videos of previous Dragon launches, solar panel fairings usually seem to be jettisoned a few minutes(can't recall exact figure offhand) after separation from Falcon9. I've never really considered what happens to them after that! At a guess, they are light enough and big enough to deorbit fairly quickly. I assume the Dragon makes a burn before they have a chance to impact.

Also the recovery ship isn't targetable, where/ what should I target for the de-orbit program?
Not quite sure about the specific problem.
For the Dragon, you should be able to set the Landing Target by pressing and entering it's name e.g. "recoveryvessel".
Does it not accept the vessel name?

No functions are active until the Dragon is free flying i.e. not attached to Falcon9 or ISS. If I recall correctly, you can not activate the Auto-Deorbit Sequence if Dragon still attached to something.

Any help?
Cheers,
Brian
 

Buck Rogers

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Thanks Brian
I'll see if I can find a video to find out what manuevers they do.
The target problem; my bad, typo, I was using a space! BaseSync and MapMFD don't recognize it as a target and I think that was what put me off, but your de-orbit program does the job very well.
thanks again for your help.
 

BrianJ

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I've never really considered what happens to them after that! At a guess, they are light enough and big enough to deorbit fairly quickly.
Had a google around to try and find some answer to this - apparently CRS-8 solar panel covers re-entered after 5 days, so yup, pretty quick deorbit.
 

Buck Rogers

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Interesting, still would have thought it would be better to dump them on the way up! Watched the CRS-14 launch video but it cuts off directly after panel extension and the spacecraft attitude wasn't clear, and no clue to what maneuvers are made. Flying in Orbiter and trying to preserve Dv my first burn is several orbits away resulting in the collision, so I still have to figure out what they're doing there.

But some things I didn't know, it's the third time they've used a secondhand dragon, and apparently the first stage didn't return and land because it was used for flight tests.
 

DaveS

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The solar array covers should clear the Dragon on their own thanks to the velocity they're jettisoned with. That should count as a impulse on its own.
 

barrygolden

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Block 4 Falcons will only be reused once so there not being landed. A block 5 is at the Cape and they will be used multiple times
 

Buck Rogers

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@ DaveS
The solar array covers should clear the Dragon on their own thanks to the velocity they're jettisoned with.
They DO clear the Dragon nicely, and disapear quickly into the darkness of space... But they comeback half an orbit later!
 

BrianJ

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They DO clear the Dragon nicely, and disapear quickly into the darkness of space... But they comeback half an orbit later!
:)
Thanks for prompting me to look into this previously neglected aspect of the Cargo Dragon add-on.

I suspect my initial thoughts echoed DaveS, in as much as: jettison->extra velocity->different orbit period->no impact.

But actually, if the jettison velocity is orthogonal to the Dragon's velocity vector (especially prograde/level horizon attitude) you don't change the orbit period by much at all.

I tried some experiments in Orbiter, starting from the CRS-14 launch scenario orbit of 300km x 350km, jettisoning the solar panel covers about 1min after orbit insertion at 300km.

Prograde/Level Horizon attitude at jettison gave the closest panel/Dragon passes.

With "Non-spherical gravity" and "Atmospheric Wind Effects" enabled,
the close approach after 1/2 orbit was ~1000m, closest approach after 1 orbit was ~100m.

With "Non-spherical gravity" and "Atmospheric Wind Effects" disabled,
Close approach after 1/2 orbit was ~1000m, closest approach after 1 orbit was ~2m. !! .

That's a bit close, although I suspect the Dragon does some orbit raise maneuvre before then.

However, the add-on panel covers don't have particularly realistic aerodynamics in the .cfg file (I never thought about it!). If you give them some drag and reduce the mass a bit, they start to behave better.

If you use the following parameters in the Config/Vessels/dragon1/dragon1_fairing1.cfg (also dragon1_fairing2.cfg), the atmospheric drag keeps the closest approach down to ~600m after 1/2 orbit, after that distance continues to increase. The covers' orbit loses about 20km per day (ran it for 24hrs sim time), so I guess that's somewhere in the "reentry after a few days" ballpark.

Code:
Mass = 25
CrossSections = 4 4 4
CW = 5 5 5
Anyway, I'll include something like that in the next update.
Cheers,
BrianJ

P.S. Here's a video(not mine) that shows really well what I saw from UK South Coast when CRS-11 passed over. To me, it looked like the panel covers were indeed jettisoned from Prograde/Level Horizon attitude, but hard to tell really.
[ame="https://www.youtube.com/watch?v=7Qw-w31TVAE"]Dragon Resupply Mission CRS 11 - YouTube[/ame]
 
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