Simulating a satellite in a lunar Near Rectilinear Halo Orbit

Orekit usage
1

Hi,

I would like to simulate a satellite in a Near Rectilinear Halo Orbit (NRHO), considering the L2 point of the Earth-Moon system. I have an initial PV state for a satellite in the CR3BP (Earth-Moon) frame and I wanted to ask you: is there a best way to carry out this simulation with Orekit? I have seen that there is
a HaloOrbit class but it seems to be not so useful for my scope…

Thank you so much,
Samuele

2

Hi @samuele

I’m not familiar with these types of simulations. Howerver, I think the Orekit tutorials about the CR3BP can help you. They are available here: src/main/java/org/orekit/tutorials/propagation/cr3bp · master · Orekit / Orekit tutorials · GitLab

The EarthMoonHaloOrbit and PropagationInCR3BP tutorials can be very useful to help you.

Best regards,
Bryan

1 Like
3

Hello @samuele
I’ve already used Orekit to simulate cis-lunar rendez-vous from Earth to Lunar Gateway.
To my opinion, CR3BP is not accurate enough.
It’s better to use numerical integration with Earth, Moon, Sun attractions, without considering a specific central body. For that, I’ve created a numerical propagator with :
setOrbit(null),
setIgnoreCentralAttraction(true)
addForceModel(new InertialForces(CelestialBodyFactory.getSolarSystemBarycenter().getInertiallyOrientedFrame()));
addForceModel(new SingleBodyAbsoluteAttraction(CelestialBodyFactory.getEarth()));
addForceModel(new SingleBodyAbsoluteAttraction(CelestialBodyFactory.getMoon()));
addForceModel(new SingleBodyAbsoluteAttraction(CelestialBodyFactory.getSun()));

Regards,
Sébastien

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4

Hi @sebastien.herbiniere,

thank you so much for your reply. In the last days I have followed your suggestion but I have a question about the first force model you applied. Why did you choose the CelestialBodyFactory.getSolarSystemBarycenter().getInertiallyOrientedFrame()? Is it because your initial AbsolutePVCoordinates are propagated in a frame which is centered at the Solar System Barycenter (e.g. ICRF)?

Thank you again,
Samuele

5

Hi @samuele,
I use here the Solar System Barycenter inertial frame as the integration frame.
Looking at javadoc of org.orekit.forces.inertia.InertialForces, we are here in the second use-case where “the inertial frame is not related to the main attracting body”. Choosing an other inertial frame (not geocentric and not Moon centered) should work in the same way.
Regards,
Sébastien

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