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Simulating Blue Origin's New Shepard Rocket

Posted 9 years ago

What do you do if Jeff Bezos releases a cool video showing a rocket taking off, separating it's cargo and then landing? Yeah, that's right: you block off your evening and simulate it with SystemModeler!

enter image description here

To start off with, not all details are known about the New Shepard. I used a FAA report (link) and some guessing to get parameters for weight, thrust, size etc. Next, to get something to start with, I modeled a pipe with a thruster on it.

Modelica model of a basic New Shepard propulsion system

This can be thought of as the rocket engine and the main propulsion body. This is what it looks like in the Animation window of Simulation Center:

3D Model in SystemModeler's Simulation Center

After verifying that this could take-off and propel the body to a high elevation I started to add the crew module:

Modelica model of New Shepard crew module

The crew module must be able to separate from the main body, so I constructed a custom component with the following equations:

f_d = d * der(s_rel);
f = if attached then c * (s_rel - s_rel0) + f_d else 0;

When the detach signal arrives the crew cabin will no longer be attached to the propulsion module. At this time the interstage will provide propulsion. That's what you see in the basicWorldForce above. Looking at the system at the time of separation it looks like this (the red arrow is a force arrow showing force on the propulsion module.):

BO New Shepard stage separation simulation

After I verified that separation worked, it was time for the toughest part: to land the propulsion module. To do this I connected a control system to the propulsion stage and started trimming it for a soft landing. Modelica model of New Shepard propulsion system

Finally, putting it all together we get the final model:

New Shepard model, Blue Origin

To sum it up, I created a simple video showing the three interesting parts: YouTube link

Note: There are many more things to add to this model. Here are some, that I challenge the community to add. I've attached the model to this post.

  • Separation based on height instead of time.
  • Simulate it to reach 100km.
  • Simulate the parachute for the cabin crew.
  • Take into account the weight change due to burnt fuel.
  • Design a better control system. (Currently it impacts the earth at 9 mph)
  • Add forces, and wings, for X and Z direction.
  • Document components & modeling assumptions.
  • Add CAD shapes to make it look more realistic.
  • Model the physics of the engines, not just "raw" forces.
  • ... Many more fun things to do!
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POSTED BY: Johan Rhodin
2 Replies

enter image description here - another post of yours has been selected for the Staff Picks group, congratulations !

We are happy to see you at the top of the "Featured Contributor" board. Thank you for your wonderful contributions, and please keep them coming!

POSTED BY: Moderation Team

This is very exciting indeed, Johan, and thank you for fabulous simulation! I added a GIF video to your post of the historic event. The press release and details from Blue Origin itself about their New Shepard space vehicle can be found at: Blue origin makes historic rocket landing. Now I would like to ask you something about your simulation.

  • Isn't this inverted pendulum problem in essence - for all stages of the rocket ?

  • If yes, then your challenge item in the post "Design a better control system" - does it concern the inverted pendulum part?

  • Can control systems Wolfram Language tools be used somehow, see for example Stabilized Inverted Pendulum or is it not necessary and everything is built in in System Modeler ?

  • I your setup, is there any simulation of external force - random perturbation - trying destabilize the rocket ?

POSTED BY: Vitaliy Kaurov
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