Project MAV - The Frisbee of Mars

[francisdrake]

This is the concept of a Mars lander and ascent vehicle, as described in Boeing's "Mission to Mars Using Six Not So Easy Pieces".

The lander weighs 40-45 ton and can transport a crew of 4 to Mars surface and back to orbit. It uses a large inflatable hypersonic decelerator for atmospheric entry. This heat shield also provides some lift during entry.

The lander is a forward-looking hover vessel, while the ascent vessel - after separation from the lander - is a tail sitter.

Key commands are in the documentation file MAV.txt. This version is for Orbiter 2016. Have fun!

 

[francisdrake]

Change log of new version MAV-02:

Changed the title of this thread to be more catchy.
Descent stage MDV now Orbiter 2015 compatible, checking touchdown points.
(Ascent stage still is not, due to mode change)
Thrusters and fuel amount modified. Can reach orbit now, with 500 kg fuel left for orbit adjustment and docking.
Scenarios updated, now for a direct landing in Gale crater.
Launch scenario allows docking with SEP flying overhead in a 200 km Mars orbit.

I would be interested in reports on handling and performance.
If somebody manages to land within visual distance of the cargo lander, please post a screenshot!

 

[Astro SG Wise]

Thank you very much. I have looked forward to the creation of this vehicle in Orbiter ever since I saw the designs. I'm going to try it now.

---------- Post added at 01:20 AM ---------- Previous post was at 12:47 AM ----------

Just a quick note, the MAV does not detach from the MDV correctly. When ctrl-J is pressed, the MAV appears in a Horizon Level position, when the MDV is at the same position it was when the button was clicked.

 

[francisdrake]

... the MAV does not detach from the MDV correctly.

You got me! This is a hack. The correct mode change from a hover vessel to a rocket would require directly manipulating the Vesselstatus by rotating the arot-vector by 90° around the x-axis. I don't know how to do that, so I just create the new vessel and let it drop to the ground, where it rightens itself on the touchdown points.

Anyway, this hack will not work for Orbiter 2015, so I have to look for a better method. If someone could point me to a working example how to manipulate the Vesselstatus I'd be grateful!

 

[Astro SG Wise]

Otherwise, I have not found anything other problems. It has handled great on re-entry, and I'll be visualizing a great deal of concepts floating around in my head with this design.

Cheers

 

[francisdrake]

A Happy New Year to everyone!

New version 03:
Descent stage MDV has now hover (!) engines

Mode change to ascent stage in upright position
-> A big thank you to BrianJ for providing the transformation code!

New scenarios for Moon and Phobos.
Scenario names have been changed, so pls empty the 'Scenarios/MAV' folder before installing the new version.

Thruster and RCS power reduced to allow for softer maneuvers
______

I would be interested in some feedback:
- Do you see entry flames?
- Behaviour in Orbiter 2015:
Does it land upright? Does it jump when extending the ladder [A]?
Can you separate the ascent stage Ctrl-[J] and launch back into orbit?

 

[pclaurent]

Orbiter 2016 update

Any plan to update MAV for compatibility with Orbiter 2016?

 

[francisdrake]

Yes, but not before Christmas, due to lack of time. I plan to update the Orion and the MAV to the 2016 SDK.

This will include 2016-style touchdown points and the pre-step time loop, so that newly created vessels (spent stages and jettisoned objects) are created where they should, not far away from the parent vessel.

 

[4throck]

Seems very interesting to have in 2016 as a generic lander (Moon, Mars, Mercury, whatever).

In fact it does land correctly on Orbiter 2016 if you disregard the slow slipping after engine shutdown

 

[barrygolden]

For a Mars lander you might think about using your MPCV CM. I would look a lot like the MEM from the late 1960's and full fill the roll of a MAV .

 

[francisdrake]

Updated the MAV for Orbiter 2016. It has new touchdown points for the terrain surface.

On landing Orbitersound callouts occur too high, as they refer to the mean planetary radius. The touchdown points have reduced friction, so the lander slides a little when landing with excess speed, to avoid toppling over.

The shadow-casting surface and the ground elevation do not quite match on Mars. The lander seems to sit above ground. But if lowered, the landing feet vanish into the ground. Also the entry flames vanished, maybe due to the different atmospheric model in 2016.

This is a compatibility update only.

 

[turtle91]

It could be my new standard multipurpose-lander in Orbiter :thumbup:, but I have some issues::hmm:

-when landed on Mars, in my case, the lander never came to a full stop (no landed IDLE...0.04 m/s all the time...nearly flat terrain).
I know, you have set-up reduced friction to avoid a flip-over in case of lateral velocity during landing, but maybe some kind of a "user controllable brake" would be helpfull.

-I am currently trying to set-up a JarvisM to launch the MAV to the Moon(MS2015 Live payload).
The problem here is the automatic gear-deployment.
There seems to be no "launch mode". So the gear is in a deployed state right after SCN-load. (the MAV recognizes the low altitude...so auto-gear-deployment kicks in)
Ok, I could use the MS2015 "non-live/mesh-only" option, but in this case, the later on ejeted MAV would appear with its HIAD.(which doesn't help on the Moon)

-What is the purpose of the "LUNAR" flag in the SCN file ?

However, I tried PursuitMFD on a Moon-landing, and all went fine.
Except the IDLE/landed issue.
At PAD1 at Brighton-Beach, I was finaly able to stop the MAV, but there was a lot of RCS-firing mandatory to force "IDLE landed"-state.

 

[francisdrake]

Thanks for testflying it and for the comprehensive report!

Reduced friction:
This is mainly due to my bad landing skills, when I got too frustrated with repeated toppling over. I will try to increase the friction to a sensible value in the next release, and maybe add a 'brake'. It came to a full standstill for me, but the transition from 'orbiting' to 'landed' may happen or not.

Launch mode:
Good point! Will make the configuration 'stowed' fully passive, so an activation key command will be necessary.

LUNAR scenario flag:
Reduces the fuel of the ascent stage from 10 ton to 2 ton only. This is sufficient for a moon launch. Only with this reduced payload the landing stage has enough power to brake from lunar orbit, as the slowdown is purely propulsive (no atmospheric slowdown).

Pursuit MFD:
I have issues with it. The autopilot quits shortly after initiating the burn with an error message and a hanging thruster. Maybe an issue with the framerate or MFD update rate. I am hoping for the new BaseLand MFD advertised in the screenshot thread.
----
Edit: Updated to version 05. Higher friction, mode 0 (stowed) is passive. Clean out the Scenarios/MAV folder first, or use JSGME mod manager to avoid mixing old and new scenarios.

 

[turtle91]

Many thanks for the feedback.
For the "reduced friction" issue, a "user-brake" should be enough.
So it's up to the user, to decide, if it's a good time for a final brake or not.
If the vessel flips-over caused by the final brake, it would be an pilot-error.

I am still trying to find workaround for the sliding-problem, which happens with other vessels, too.
Maybe a MFD, which creates a phantom-vessel in landed/IDLE state at current position and attaches the user-controlled vessel....something like this...(like MS2015 does).

Regarding PursuitMFD:
I am still using "my" 2016-compat-build. And don't have such problems.
With the new released PursuitMFD2016, I have multiple issues.
I guess it works "too precise", and this causes problems on my system:
-If using docking-mode
=the MFD acts too precise (somewhere in the nano-meter-range ?).
So if using the default Atlantis for example, I am runniing out of fuel during docking....too many never ending RCS-bursts.
-landing-mode tried on Mars (stock DG)
sometimes it works..sometimes I got strange results, which might end up to a crash-landing. In my case, this could be an issue with low-MFD-refresh-rate. My system is not strong enough to use higher refresh rate-settings.

And thanks for clarifying the LUNAR-mode..makes complete sense to me now.

Ups...I have just realized, that you have allready updated the MAV with a dedicated launch-mode:thumbup:.
I will give it a try now.......



I have tried to setup the launcher, and "MODE 0" does now do the trick (gears not extended), but how to get remove the HIAD for a moon-mission ?

My SCN looks like this:

MAV:MAV\MAV
STATUS Landed Earth
POS 177.3981678 -2.5194793
HEADING 270.11
ALT -577821515.249
AROT 0.000 -0.000 0.000
ATTACHED 1:0,Jarvis_B
AFCMODE 7
PRPLEVEL 0:1.000000
IDS 0:588 100
NAVFREQ 0 0
XPDR 468
MODE 0
LUNAR
END

But its shows still the HIAD until separation.
After separation from the second-stage, the HIAD is gone(might be caused by the LUNAR-flag).
Is ther a way to force the HIAD not to be visible during launch(if using "LUNAR" flag)?
If so, the MAV would matches the Jarvis 10-meter diameter fairing perfectly.



EDIT:

Just completed a moon-test mission:
-TS Tugboat to ISS via Quasar SHLV
-MAV (in LUNAR mode...on top of a Jarvis-B) launched into ISS's plane
-for the crew...launched the Orion (Jarvis-B) to the ISS to meet the TS Tugboat
-TS Tugboat catched-up the waiting MAV
-off-plane Moon transfer with MAV docked to tugboat
-reached circular orbit around the moon at an altitude of 125 km
-undocked the MAV and used PursuitMFD(the old version) to set-up the automated landing
=
all went fine, the MAV started to descent without any issues (cross-range to base about 3.9 km...initial altitude still 125 kms)
right after landing, the vessel stopped...no sliding around.
So...all in all...a complete success so far.
The only issue is the visual glitch with the HIAD in "LUNAR launch-mode" as I mentiond before.

 

[francisdrake]

This is really a great test mission you flew, sounds impressive!
Maybe you could post one or two screenshots?

Thanks for clarifying the PursuitMFD topic.

Friction:
I increased the friction factor to 1, was 0.2 before, and made the landing legs a little softer. On Mars I could land still with some forward speed, provided the vertical touchdown speed was easy, to avoid being catapulted up, which usually leads to toppling over.

Lunar:
Please try dll attached to this post, in the file "MAV no HIAD lunar.zip".
Just replace the dll in the modules folder.
It supresses the rendering of the HIAD when the LUNAR keyword is set.
Please note:
You still have to press [D] to switch the lander in descent mode, so it will auto-deploy its landing gear at 3300 m above ground.
Or you deploy the gear manually with the [G] key.

 

[Interceptor]

turtle91,when you saythe old version of pursuit mfd,do you mean the one you compiled,or the old 2010 version?

 

[turtle91]

@Francisdrake
Many thanks for the new fix. This was fast...:thumbup:
I will try the whole mission again, but I need to fine-tune the MS2015 payload-offsets a bit more precise, before doing some screenshots...but I will do.
Btw., I forgot o mention...after PusruitMFD has done its job, I have had 1.56 tonnes of fuel left. So even if something would go wrong during final landing, I would have enough fuel to perform some manual intervention.

@Interceptor
You are right, using the acronym "old version" could cause confusion.
I used the 2010-version, which I have compiled for Orbiter2016(which checks for new surface altitude).

I am not sure, if the link points to the exact same build I am using, so have attached the exact version, which I am currently using.

 

[Interceptor]

Thank you turtle91.:thumbup:

 

[francisdrake]

Thanks for sharing this PursuitMFD version!
It works flawlessly. Finally an MFD to bring me home in Orbiter 2016

The remaining fuel is good. I had 1.6 ton left for the Brighton Beach scenario.
The idea was to have some extra fuel either for extended hovering, or for short ballistic hops, to explore new terrain.

 

[pclaurent]

Thanks to both of you for providing a way to land safely on the moon onboard MAV. I used the new DLLs for Pursuit and MAV. The modified Pursuit MFD works fine and is the perfect successor of the good old LOLA. I successfuly landed on Apollo 11 landing site with MAV in LUNAR mode (just added LUNAR in the scenario, not sure if it's the good way...) with... 65 kg fuel remaining! (but my initial approach was probably not optimized).