New Release Crew Dragon DM2

BrianJ

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Hi,
another version of CrewDragonMFD - v.220425
This fixes a couple of bugs related to opening a second CrewDragonMFD screen (although not much point in having two screens for it, since it can only control one Dragon at a time).

Also, a couple of small tweaks for more accuracy.

Requires about 80kg of fuel for RCS during reentry.
Can handle ~80km cross range error and 1500kg payload.

I think I'll include this version in the DM2 add-on, if no further bug reports.

Thanks to everyone for the reports/feedback,
Brian
 

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Max-Q

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Is source code available? Now that DM2 dragon has a reentry autopilot, I would love to update my Deep Space Dragon add on, but I would need to tweak the deorbit autoburn stuff a bit.
 

BrianJ

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Is source code available? Now that DM2 dragon has a reentry autopilot, I would love to update my Deep Space Dragon add on, but I would need to tweak the deorbit autoburn stuff a bit.
Hi,
yes, source code in attached .zip - but it's embarrassingly terrible, I don't really know what I'm doing with MFD's!
The deorbit burn code is lifted straight from the Cargo Dragon, and I have forgotten what it all means exactly! I was looking at it and shaking my head in bafflement.
But you're welcome to see if you can do anything with it.
Or you can explain what you want it to do (reentry from Moon or Mars?) and I can see if I can work something out.
(I was thinking it would be good to have an option for reentry from interplanetary space).
Be aware that the MFD sends a key-press to the Dragon to confirm the vessel IS a Dragon and returns the status of the hatches/lights/etc. - so you'll need to be using the latest DM2/Inspiration4 .dll's - or accomodate that within your Dragon module.
Cheers,
Brian

P.S. PM me if you want help deciphering my garbled code - I'll do my best to help!
 

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Max-Q

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yes, source code in attached .zip - but it's embarrassingly terrible, I don't really know what I'm doing with MFD's!
Neither do I!

The deorbit burn code is lifted straight from the Cargo Dragon, and I have forgotten what it all means exactly! I was looking at it and shaking my head in bafflement.
But you're welcome to see if you can do anything with it.
Nice! (That means the same "hack" I did for my old deep space dragon addon will work just fine) ;)
Basically, I just need it to point the Dragon retrograde instead of prograde and fire my trunk mounted SPS instead of the fwd bulkhead Dracos.

Or you can explain what you want it to do (reentry from Moon or Mars?) and I can see if I can work something out.
(I was thinking it would be good to have an option for reentry from interplanetary space).
Sure. Nothing fancy, just roll reversals to keep the G-load reasonable and not skip out of the atmosphere. Intended for reentry from deep space (especially lunar missions and stuff). However, I do have one mission (Venus Flyby) that comes in pretty hot... 12,739 m/s :cautious:

Be aware that the MFD sends a key-press to the Dragon to confirm the vessel IS a Dragon and returns the status of the hatches/lights/etc. - so you'll need to be using the latest DM2/Inspiration4 .dll's - or accomodate that within your Dragon module.
I do need to tweak some code in the dragon DLLs to add the main engine (so yeah, new DLLs), I will take a look at how this works.
 
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Max-Q

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Ever thought about a Lunar Dragon that could land. might need to look at that
The dV (and thus, propellant) requirements would be... prohibitive.
It takes about 1000 m/s get into lunar orbit, then about 2200m/s to get down to the surface, and another 2100 m/s or so to get back to orbit. Plus about 1000 m/s for TEI, add it all up and that's 6300 m/s total... assuming a perfect trajectory, and a spacecraft with a mass of 7,000 kg dry.
By my "back of the napkin" calculation, this would be a wet mass of around 36,000kg to TLI... So yeah, you could do it, but it would take a Saturn V! That is assuming an isp of 390 seconds (CTF/Hydrazine), so using a safer oxidizer like NTO would push your mass to TLI to around 49,000kg to TLI.
Possible, sure. But not practical. Same reason the Apollo Direct Ascent idea was dropped. Why carry all that heavy "return to earth" stuff to the lunar surface?
 

BrianJ

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Nice! (That means the same "hack" I did for my old deep space dragon addon will work just fine) ;)
Basically, I just need it to point the Dragon retrograde instead of prograde and fire my trunk mounted SPS instead of the fwd bulkhead Dracos.
Ah. You might want the latest DM2/Inspiration4 code then. Attached in .zip.
The new keypress stuff is in the clbkConsumeBufferedKey() section.

The CrewDragonMFD gets the vessel interface, sends a keypress command, and the returned value is all the various status indicators for hatches etc.
The MFD also uses the same method to confirm the vessel is a Dragon.

I just tried setting up a reentry from 1.5Gm apogee, reentry interface velocity ~10.5km/s, and it wasn't too bad - overshot by ~220km, 5g max load. That was using IMFD BaseApproach: Alt.120km, ReA 6deg, Ant 45deg.
I'll give it a few more tries and see if the CrewDragonMFD can handle it "as is" with the right entry interface parameters for IMFD.

Cheers,
Brian
 

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barrygolden

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The lunar dragon to land would need a deorbit system and the Draco's for the final landing burn. It would need legs as well instead of the little wings it would need fold out solar panels like Dragon 1 and the hatch would open down and a ladder comes out. I saw a ring of gold tanks with an engine on the nose but might need it on the back as the deorbit motor and then with fuel in the trunk to feed the Draco's for ascent
 

francisdrake

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MoonDragon1.jpg
I once tried to make a MoonDragon lander.
Stripped the outer hull of a Dragon capsule, only keeping the pressure shell. Added extra fuel tanks on top. The vessel would lauch unmanned and be transferred to Luanr orbit by a deep space propuslion stage (not shown here). The crew would then come in seprate ship, like a DeepSpace Dragon, board the MoonDragon lander, land and return to Lunar orbit later.

Delta V was about 2.8 km/s with hypergolic fuel. I dropped the concept as it did not look too promising.
 

barrygolden

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Hey that is a pretty neat idea. I wonder if you could land on the Moon using the same profile as the F9 first stage with a short deorbit burn followed by a slow down burn then the landing burn. Seems like a way to save on fuel . I did see a pic of a Dragon 2 landed on the Moon with the same landing legs as the F9 has but can't find it
 

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I wonder if you could land on the Moon using the same profile as the F9 first stage with a short deorbit burn followed by a slow down burn then the landing burn.
No. F9 first stage uses aerodynamics to slow down to low enough speeds for the landing burn. To get from lunar orbit to a soft landing, you have to kill all of your velocity somehow, and without an atmosphere the only way to do it is with thrust.
 

BrianJ

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Hi,
...another version of CrewDragonMFD....v.220516
Extended functionality for orbits above 600km.

Changes:
Added [MOD] button to switch between reentry modes: LEO / GEO / HYPER

LEO - for orbit apogee up to 600km (reentry velocity ~7.7 km/s)
GEO - for orbit apogee 600km to 40,000km (reentry velocity 7.8 - 10 km/s)
HYPER - for orbit apogee 40,000km to hyperbolic (reentry velocity 10 - 13.5 km/s)

Auto De-Orbit function only available for LEO mode.
GEO and HYPER modes display parameters for IMFD Base Approach reentry interface (Alt, ReA, Ant)

Removed the (somewhat redundant) heading data, to make room on display.

It's getting a little over-complex, but I thought the ability to handle higher reentry velocities might be useful for Max-Q's "Deep Space Dragon" add-on :)

Attached .zip package includes C++ code.

Cheers,
BrianJ
 

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barrygolden

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ar orbit later.
I think your on to something with this lander. I would move the ring of fuel tanks to the bottom and they would somewhat be the size of the service module. it would need landing windows and would launch on a Falcon heavy. I see a space tug has been done so dock with a manned Dragon and land on the Moon then redock and fly home. When space X shows off its EVA suits we should be able to use those for EVA's. I still think we would need the descent stage that stays on the Moon and a new one fueled up could be used for Artemis 4
 

BrianJ

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Hi,
in the last version of CrewDragonMFD, I forgot to update the "No Target" Auto Re-Entry algorithm for GEO and HYPER modes.
Sorry about that!
I think this version fixes it....

CrewDragonMFD v.220522
.zip file attached, includes MFD module, C++ code, readme.
 

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