# Questions tagged [celestial-mechanics]

Questions regarding the movements and interactions of astronomical bodies as it relates to spacecraft, their trajectories, and their maneuvers. For the motion of spacecraft themselves, see [orbital-mechanics].

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1answer
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### Besides retarded gravitation, anything else to worry about when calculating MU69's orbit from scratch?

For fun I'd like to use Hubble Astrometric data for example the observations listed at the bottom here to numerically estimate the orbit of 2014 MU69 as well as its uncertainties. My plan is to use ...
6answers
16k views

### How would we move Venus or Mars into Earth's orbital zone? [closed]

(See the more focused version of this question: How long would it take to move Venus and Mars into Earth's orbital zone using gravity assist?) What methods and time scales might be involved in moving ...
2answers
201 views

### What is the analytical closed-form solution of the two-body problem to verify its numerical integration results?

The purpose is to study the motion of two celestial bodies analytically. What is the closed-form of the two-body problem if I was to solve it analytically without using a numerical approximation ...
1answer
13k views

### What is the escape-velocity for our galaxy?

What should be the escape velocity for our galaxy and can we calculate it? For instance, if we assume that we don't know the mass of our galaxy, you may consider it as small 'm'.
1answer
133 views

### What is the physical interpretation of the eigenvalues of the monodromy matrix and how are they associated with the invariant manifolds?

To define the monodromy matrix, assume that the period for one cycle of a halo orbit is denoted as $T$, the initial time as $t_0$, and the state-transition matrix is defined as $\phi$. Then, the ...
1answer
429 views

### Understanding gravitational keyhole analysis for Near-Earth Objects

I've been studying the resonant return and gravitational keyhole analysis for NEOs and using the extension of Öpik's theory of close encounters (aka Öpik-Valsecchi theory, Valsecchi et al., Astron ...
1answer
78 views

### Is the Jacobi constant stationary along a periodic orbit?

In the book called "Chaotic Worlds: from Order to Disorder in Gravitational N-Body Dynamical Systems", link here, the author states that if the dynamical system has an integral of motion which is not ...
3answers
2k views

### Python API for JPL Horizons?

I found the python package HorizonJPL in the Python Package Index, but it looks like it's limited to activity in 2013. When I go to the linked documentation page https://docs.google.com/document/d/...
2answers
1k views

### Have there been any photos taken of a total Earth-Sun eclipse from the Moon, or its vicinity?

There's a supermoon lunar eclipse ongoing right now (Sept. 27/28, 2015), and it got me thinking that a great way to show to people why the Moon is reddish -- when eclipsed by the Earth -- would be if ...
1answer
1k views

### C3 calculation in interplanetary missions

I'm starting to study Astrodynamics and I'm trying to make a Porkchop plot for a Mars mission to compare the results with actual porkchop plots which I found on the internet, so I know if my ...
2answers
844 views

### Source for up-to-date values of Mars' standard gravitational parameter

Wikipedia currently gives the standard gravitational parameter of Mars as: $$GM_{Mars} = 4.2828(9) *10^{13} (m^3/s^2)$$ The (9) is the uncertainty of the last digit, so it works out to about ...
1answer
2k views

### “Pythagorean Three Body Problem” - need some points from an accurate solution for comparison

note: if you up-vote (or even if you don't), don't forget to scroll down and see the excellent answer as well - it's beautiful! The Pythagorean Three Body Problem also know as Burrau's problem is a ...
2answers
273 views

### What are the perihelion and aphelion distances of the Falcon Heavy second stage?

What are the perihelion and aphelion of the Falcon Heavy second stage containing the Tesla after yesterday's mission?
1answer
119 views

### Calculate NEO object position with nasa Near Earth Object data

I am using the nasa NEO object data: Listing Of NEO's: Nasa NEO Data Specific NEO Data: Object Data Given the information in this JSON data. Is it possible to calculate the position of the NEO in ...
2answers
369 views

### Ephemeris for lunar body-centered body-fixed coordinates?

I'm going to try to do a modest simulation of the Moon's libration as seen from the Earth (geocenter), similar to the technical one's I've shown in this question. I'll do it in Python and render it in ...