Linked Questions

13 votes
2 answers
2k views

Can the Right Ascension and Argument of Perigee of a spacecraft's orbit keep varying by themselves with time?

I came across the orbital data for a low Earth orbit spacecraft and one thing which I am not able to understand is why does its Right Ascension of ascending node and Argument of Perigee keep changing ...
ModCon's user avatar
  • 273
5 votes
5 answers
2k views

How to determine an algorithm for Low Earth Orbit propagation, considering perturbation from the moon, sun, etc?

I'm trying to determine an algorithm for orbit propagation for a satellite on LEO, with high accuracy in a six month time ...
Tarlan Mammadzada's user avatar
7 votes
2 answers
1k views

Physical meaning of perigee advance

I'm starting to study orbital perturbations and I can't find any physical explanation about the perigee advance (apsidal precession) when considering Earth oblateness effects. Can someone give a ...
Julio's user avatar
  • 1,732
6 votes
1 answer
2k views

Orbit Propagator with J2 perturbation has larger error compared with simple 2 body Propagator

I have developed an orbit propagator, taking J2 perturbation into account according to the formulation as shown: with Runge-Kutta 4th order, timestep of 1 second as the integrator. Formulation as ...
Chia Jiun Wei's user avatar
4 votes
2 answers
230 views

Have gravitation multipoles of Jupiter and Saturn beyond J2 been measured or at least estimated? At least the zonal harmonics?

This excellent answer has me wondering if there are any measurements or estimates of gravitational multipole moments of Jupiter or Saturn beyond J2. Here is what I found for J2 (in unitless form) in ...
uhoh's user avatar
  • 149k
8 votes
1 answer
721 views

Why is Nodal precession affected by the rotational period of the planet?

The $J_2$ term in Nodal Precession equation has the rotational period of the planet. I understand that the oblateness of the sphere with an equatorial bulge induces a torque on the orbit of a ...
karthikeyan's user avatar
  • 4,479
2 votes
1 answer
982 views

Equation for orbital period around oblate bodies, based on J2?

In this answer I point out that the period of items (ring particles, moons, spacecraft, etc.) around an oblate body will not scale exactly as $a^{3/2}$ because the closer you are to the planet, the ...
uhoh's user avatar
  • 149k
5 votes
1 answer
470 views

Trouble deriving rectangular components of acceleration of satellite in orbit around Earth with J2 consideration

I am trying to derive the rectangular components of acceleration for a satellite in orbit, with Earth oblateness in consideration, in order to use the RK4 method to find the updated position and ...
arah's user avatar
  • 55
5 votes
1 answer
265 views

Satellites below perigee on Stuff in Space website

A friend of mine noticed that many satellites on the Stuff in Space website can reach an altitude lower than their declared perigee, as you can see in the following screenshot: We observed these ...
xonya's user avatar
  • 153
4 votes
1 answer
266 views

Are there chances to get a Hubble + ISS Moon transit picture?

I have seen these cool transit pictures where ISS is transiting the moon ISS is transiting the Sun Hubble is transiting the moon I even saw picture of ISS Sun transit during solar Eclipse Tiangong ...
Ash's user avatar
  • 383
5 votes
0 answers
489 views

What is the sign of Earth's J₂?

From Wikipedia's Geopotential model; The deviations of Earth's gravitational field from that of a homogeneous sphere and the question For the mathematical relationship between J2 (km^5/s^2) and ...
uhoh's user avatar
  • 149k
4 votes
1 answer
213 views

Mechanics of Sun-Synchronous Orbit & North Korea's KMS-4

QUICK QUESTION: Is North Korea's KMS-4 in a proper Sun-synchronous orbit? https://www.n2yo.com/?s=41332 2016-009A FOLLOW-UP QUESTION: How do I tell? I want to understand the mechanics. RESEARCH:...
Jon17's user avatar
  • 41
3 votes
0 answers
178 views

Quantitatively, how deep are the stable equilibrium points in GEO? How much delta-v needed to move from one to the other?

This answer discusses a spacecraft in GEO using a two-impulse (circular → elliptical → circular) raise & lower maneuver to move (phase) itself by 180 degrees in longitude then return to synchrony. ...
uhoh's user avatar
  • 149k