Author Topic: I've made a gravity and space simulator with open NASA data! (Read 1790 times)

HappyKoala · « **on:** 01/16/2019 12:54 pm »

Over the past few months I've leveraged data and 3D models from NASA that is open source to build a space and gravity simulator. You'll find it here: https://thehappykoala.github.io/Harmony-of-the-Spheres/

It's freaking awesome that NASA provides all this data and models not just to the American public, but the whole world... So I tip my hat to the fine folks at NASA that produced this data and those that makes it available in an accessible format!

If there's a scenario you would like to see included, let me know! Missions where you have to take trajectory adjustments into account can be a bit tricky as I'm yet to include things like thrusting and attitude control; right now it's just a gravitational n-body simulation, but I'm working on changing this!

Spaceflight scenarios that I have included thus far with direct links:

- Voyager 2 flyby of the Neptune system https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/The%20Sun%20and%20the%20Neptunian%20System

- Apollo 11 free return trajectory (fortunately they never had to use it!) https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/Apollo%2011%20-%20Free%20Return%20Trajectory

- New Horizons Jupiter gravity assist and subsequent journey to Pluto https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/Journey%20to%20Pluto%20-%20New%20Horizons

- The orbit of the TESS space craft https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/Finding%20New%20Worlds%20-%20TESS

- Juno's orbit around Jupiter https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/The%20Sun%20and%20the%20Jovian%20System

- Ulysses journey to Jupiter and subsequent gravity assist which brought it into a polar orbit around the Sun https://thehappykoala.github.io/Harmony-of-the-Spheres/#/scenario/Ulysses%20-%20Leaving%20the%20Ecliptic

Have a nice day, folks!

HappyKoala · « **Reply #1 on:** 01/16/2019 12:57 pm »

One thing I forgot to mention, you can click the camera tab to change the position and focus of the camera, so that, for example, you can view the Voyager 2 flyby of Neptune from the point of view of Voyager 2

. Alright, I'll go hide under a rock, now.

RedLineTrain · « **Reply #2 on:** 01/16/2019 02:49 pm »

It works! Very nice.

HappyKoala · « **Reply #3 on:** 01/16/2019 03:09 pm »

Thank you! And my apologies for posting this in the wrong section... Noticed it was moved from the general to hobby section.

I'm Darrell, by the way, nice to meet you guys!

Finn Mac Doreahn · « **Reply #4 on:** 04/23/2019 04:36 pm »

I just tested this out,and learned two things:

By making Pluto the mass of the Earth,you can get rid of its moons! Who knew?

Changing the gravitational constant makes for some wacky times.

Also,I'd like to request the following scenarios:

51 Pegasi

The flight path of the Columbiad (from Jules Verne's From the Earth to the Moon and Around the Moon)

Beresheet flight path

The ISS

The demise of Skylab

The demise of Mir

The journey of Galileo

The journey of Cassini

The orbit of Kepler

87 Sylvia:the asteroid with two moons

Bronson Alpha/Beta from When Worlds Collide

blasphemer · « **Reply #5 on:** 04/23/2019 04:59 pm »

Nice!

What method are you using to integrate Newtonian equations? I went with velocity Verlet in my (not public) simulator, due to it conserving energy and being simple, fast and still accurate compared to more complex methods.

HappyKoala · « **Reply #6 on:** 04/23/2019 06:19 pm »

Finn Mac Doreahn - Those are some pretty awesome scenario suggestions! I'll make sure to implement them provided I can find accurate data (bit doubtful about MIR, but who knows!).

HappyKoala · « **Reply #7 on:** 04/23/2019 06:28 pm »

blasphmer - Thank you for your kind words! Depends on the scenario, but there's a whole array of integrators to choose from, and you can click on the physics tab to the right and change the integrator for a scenario using the integrator dropdown menu. There's Euler, Velocity Verlet, RK4, the RK45 scheme that has an adaptive time step and so on... The crown jewel would be the 12'th order Runge Kutta Nystrom routine with an adaptive time step. It is insanely accurate.

The project is open source, so if you are curious about the integrators, you can delve into the code here: https://github.com/TheHappyKoala/Harmony-of-the-Spheres/tree/master/src/js/Physics/Integrators

Yea, some of the integrators are symplectic while others are not. For very long term simulations symplectic ones are yay, but ones that don't conserve energy can be very good at estimating the acceleration induced on a body and as such are better for producing elliptical orbits with a high degree of accuracy. NASA uses a lot of non symplectic integrators for trajectory planning.