Project Little Joe

[4throck]

Hi all,

Following discussions on the Mercury improvements thread, I started working on the Little Joe rocket mesh. Having only experience in texturing and modeling, it took me several tried to get things together and grasp the basics of multistage and spacecraft3.

This the first result that looks something like the Mercury Little Joe and works. Parameters are inaccurate but the rockets flies and the capsule separates propelled by the escape tower.
The next step is adjusting the model placement and putting a parachute on the Mercury capsule.

If someone wants to help, namely with the spacecraft3 incarnation of the Mercury capsule + parachute, the are welcome.
Also, any ideas on how to get the rocket to launch at an angle from vertical ?

Further down the road, I'll model a Mercury mockup capsule mesh with the correct paint scheme. For now I'll setup everything with the available Mercury project meshes.

 

[liber]

You could add chute to your capsule.

K - for chute...

Here's example...

 

[Urwumpe]

You can make the touchdown points of the spacecraft have an angle to the XY plane. I did this pretty often for rocket tests. Just remember that all three touchdown points form a triangle in local vessel coordinates.

 

[4throck]

You can make the touchdown points of the spacecraft have an angle to the XY plane...

Do you mean to model itself? Then use thrust direction or something? I'm using multistage for the stack with capsule as a spacecraft3 payload.

Here's an updated screenshot of the rocket mesh and textures. It is lacking the capsule adapter, and apart from that it look good to me.

 

[Urwumpe]

No, to the vessel in Orbiter. You can define three points around the spacecraft, on which it sits, for example the landing gear. These three points can be anywhere.

If you choose the right angle between Z axis and the plane of the three touchdown points, you can lift-off with a pitch other than 90°.

For example, for 75° liftoff angle:

You select the first point, the "nose landing gear" point. Just select it in the YZ plane.

Now, you can calculate the Z coordinates for the other two points, as you get a orthogonal triangle in the YZ plane:

z + h = tan(90°-75°) * (2*|y|).

If you use y = -5m for the first touchdown points, the others have to be at Z + h => 2.5881905 m below the first touchdown point.

So, you can use for example: (0, -5, -10) (-5, 5, -12.588) (5, 5, -12.588)

 

[tgep]

I'm so glad to hear someones working on the " LITTLE JOE " series. I have the original but it never worked right. I look forward to testing it out and adding it to the historic flight test schedule. Will you be doing Gemini and Apollo versions of the Boilerplate test series as well ?

 

[Andy44]

There was once talk of NASA building an Orion version of Little Joe to test the LES. That would've been cool.

 

[4throck]

Will you be doing Gemini and Apollo versions of the Boilerplate test series as well ?

For now, just the Mercury Little Joe, mostly to learn about 3d modeling and orbiter add-ons. Don't expect it to be perfect, as it is a test rocket to me.

Here's a screenshot of a boilerplate capsule on top of the rocket. Texturing is wrong in places and the model is rough, but it shure looks cool to me !

 

[4throck]

I'm working now on the launch pad. It will include the rocket support structure. For it will launch in a completely vertical, as I couldn't get it to be on the surface at an angle. The Mercury boilerplate capsule is very rough and lacks the parachute (see some images here). Beach abort is also functional, but very rough.

Anyway, when the pad is ready, I'll release it on Orbiter Hangar. Then if someone wishes to help with further development, they are welcome.

 

[4throck]

Got the pad working... wrong scale and basic materials but getting there !

 

[tgep]

Looking real good ! Don't worry, getting things right takes time, especially when dealing with both Multi-stage and SC3 ini files.

 

[Star Voyager]

Mr. 4throck, can these textures be used on the Project Mercury capsule?

 

[4throck]

The capsule here is a different mesh with separate textures. It a spacecraft3 vessel, meaning that there's no parachute or landing bag!
What is possible is to implement the Atlas and Redstone rockets using multistage and then use this capsule as payload.

I'll release a first version when the basics are fixed: height above ground, basic rocket range and burn time, good separation of the spacecraft without hitting the rocket, etc.

 

[Star Voyager]

Is it almost finished? And how would I implement the Atlas and Redsstone using multistage?

 

[4throck]

It's going! liber has made a very nice parachute for the capsule, and helped with the general setup with multistage. As much as the real LittleJoe, this is a test rocket for me and part of my learning process regarding orbiter addons. So progress is slow but steady.
The mercury boilerplate capsule is implemented using spacecraft3. So you can set it up as a payload for a multistage version of the Atlas, for example (see the Ranger or Atlas A/B addons for example).

 

[Star Voyager]

Okay, thanks!

 

[4throck]

Some screenshots of the first "oficial flight" in Orbiter.

http://orbiterspaceport.blogspot.com/search/label/Little%20Joe

Performance and guidance is close to the real thing, so I came within 10km of the desired ~88km apogee.

 

[4throck]

Finally, I've released a beta at OH: [ame="http://www.orbithangar.com/searchid.php?ID=4112"]Mercury Little Joe[/ame]

It should work and fly according to the actual sequence of events. I'm simulating Little Joe 2 so you should get up to around 88km.

Separations and boilerplate capsule need more work for it to reenter the proper way. It losses too much speed as it is. I'm more into 3D modeling and texturing, so I did my best.

Anyway, If anyone what's to investigate real parameters, feel free to do so and post here any changes to the config files.

Have fun !!!

 

[Star Voyager]

I'm having some trouble with the capsule. When it jettisons, it disappears. There is no info in the log that indicates a failure. Any suggestions?

 

[4throck]

That's strange... the configuration is very simple for the rocket+capsule, so I don't see any reason for it to become invisible at that time. I've had problems with invisible spacecraft on some add-ons, but I traced those to an incorrect spacecraft.dll version. In that case, besides not appearing, there was no fuel or control for the vessel.

Can you operate it from the inside?
Did you manually separate the capsule from the rocket?
Can you see the rocket and the escape tower when that happens?