# Questions tagged [orbital-mechanics]

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. For the movements of celestial bodies, see [celestial-mechanics].

1,494 questions
Filter by
Sorted by
Tagged with
32 views

### What are the specifications for electrical connectors that can be used for repeated mating in space?

We’re working on an interface between satellites that when docked has to transmit power and data. The interface needs to have a port for transmitting power and data. Majority of the connectors ...
187 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 ...
144 views

### When was Lucy's mission first scripted in Excel and why is that what Lockheed Martin chose to do it with?

CNBC's NASA spacecraft launches toward Jupiter asteroids on an intricate path charted by Excel Years before Lucy took off, Lockheed Martin mission architect Brian Sutter used Excel to chart the ...
290 views

### For any state vector of a satellite at an arbitrary time T1, is there another state vector at a given time T2 that will result in the same orbit?

I recently found the question In a 3D space defined by semimajor axis, eccentricity and inclination, what would be the shape of the space where SDP4 works better than SGP4? and have become interested ...
135 views

### Number of satellites needed for global 4-fold coverage as a function of altitude?

I want to estimate how many satellites (and how many number of planes) are needed for achieving a 4-fold global coverage on earth (global coverage with at least 4 satellites in view in each location). ...
63 views

### Is there a known solution for optimal impulsive transfer between two arbitrary elliptical orbits?

If not, what optimization methods or tools do people use? (Code libraries?)
123 views

### How to calculate a time to rendevouz an orbital object

I need to fly from one orbit to another to dock with station. So, station should be near the my position when I arrive to it's orbit. I can find the station's position at time T, but how to find this ...
120 views

### How to find eccentric anomaly by mean anomaly?

Wikipedia gives me the equation M = E - e*sinE I have M and need to find E. How to do it?
130 views

### What is the rationale behind NORAD's use of TEME?

The most popular catalog of Earth-orbiting objects is NORAD’s. The catalog provides the so-called « two-line elements » (TLE) which essentially are computed orbital parameters of a catalogued object, ...
107 views

### High latitude launch sites

I have two questions: What is the hype about launching rockets from high latitude launch sites? For references: Andoya Space (Norway) and ESRANGE (Sweden) received grants of > 20 M EUR. Wouldn’t a ...
1k views

### How can we avoid collisions when moving from one orbit to another?

Imagine that my ship is parked in LEO and needs to transfer to a higher orbit. It makes a Hohmann transfer and flies to the needed orbit by an elliptical trajectory. But this trajectory is crossing a ...
171 views

### How to fly from Earth to Mars if the differences between phase angles is too big for Hohmann transfer but we have fuel for other transfers?

Hohmann transfer is possible when Earth and Mars positions are appropriate for this https://ai-solutions.com/_freeflyeruniversityguide/interplanetary_hohmann_transfe.htm This happens one time in two ...
299 views

### Are 3 points on an orbit enough to determine the shape of it in practice?

In a question about determining orbital elements from two points on an orbit, some discussion arouse regarding how many points are actually necessary, since two is not sufficient. Determining a conic ...
712 views

### What can be determined about an orbit if it passes through two points

Using a 3D Cartesian coordinate system if we know for certain that a craft will pass through two points in it's orbit (let's call them p1 and p2) and we also know the mass of the central body it is ...
43 views

### Exoplanet orbitable in permanent umbra?

Does any planet, or Kuiper Belt Object, or exoplanet measured or surmised, orbit its star either fast enough, or slow enough and thus distantly enough to cast a long enough shadow, for a spacecraft to ...
231 views

### 2 body equations of motion in 3D

How do you write the 2 body equations of motion in 3D as a system of differential equations
36 views

### Find the Orbital Inclination given all other Elements and a Position on the Ellipse

I'm in a situation where I need to determine an orbit's inclination. At my disposal I have all of the orbit's other Keplerian elements, and I have the vector of a single point on the ellipse. Is ...
2k views

### Are any Earth orbits in continual shadow of the Earth?

Do any orbits around Earth leave the spacecraft in permanent shadow? If not, what is the minimum amount of time that a spacecraft must be exposed to sunlight on average?
69 views

### How would you calculate the Delta-v needed to intersect a target on the ground on a sub-orbital trajectory?

Let's say I have a sub-orbital trajectory, meaning I'm going to crash into the earth at some point within the first orbital period. I know the true anomaly in which I will impact the surface and by ...
195 views

### How would you calculate a Hohmann transfer going towards the sun?

If you were going from a lower orbit to a higher orbit such as a Earth-Mars transfer, you would use the periapsis of the transfer orbit in the vis-viva equation to calculate the delta V. But if you ...
136 views

### Orbital Mechanics and Launching into the Sun

Astronomy.com's Here's why we can't just rocket nuclear waste into the sun is an excellent explanation of the delta-V required to launch from Earth orbit into the Sun (30 km/s) vs. to escape from the ...
355 views

### Optimal inclination for a long term LEO station serving as an intermediate stop to and from the Moon

Consider we want to build a long term LEO station which serves as an intermediate stop for flights to the Moon and back (possibly with aerobrake). Refueling, docking, crew transfers etc. Several ...
42 views

### Mass production rate vs mass consumption rate in solid rockets

Do the two terms mean the same? mass production rate, mass flow rate and mass consumption rate in a solid propellant rockets.
122 views

### What's the point of characteristic energy?

My understanding of orbital mechanics is that delta-v is the most useful notion of ability to change orbits in space, akin to energy being the most useful notion of the ability to do work. But if ...
3k views

### When burns are made during inefficient parts of the orbit, where does the lost energy go?

Any Kerbal Space Program player will know that burns prograde and retrograde to the velocity vector are most efficient closest to the body being orbited, while burns normal and anti-normal are most ...
759 views

### Is there a way (working or in development) to track satellites in lunar orbit like we track objects in Earth Orbit?

I understand that Earth orbiting satellites are tracked using technologies such as radar, but due to the distance between the Earth and the Moon, they aren't really useful for Moon sats. Is the ...
33 views

### Why will the SunRISE mission "fly slightly above geosynchronous orbit"?

The blots.nasa.gov article NASA’s SunRISE Mission Studying Solar Particle Storms Moves Toward Launch says that the upcoming SunRISE mission — short for the Sun Radio Interferometer Space Experiment — ...
231 views

### What factors would contribute to a spacecraft's ability to maintain a very low orbit (VLEO) or at least orbits with very low perigees?

I asked What does account for a high coffin corner of a plane? in Aviation SE. Now I wonder what factors would contribute to a spacecraft being able to maintain low circular orbits (e.g. within 200 km ...
43 views

### Design and optimization of a Sun-synchronous repeating ground track orbit constellation

I am currently researching about this topic and am very new to this. Have no clue how to go about designing a group of imaging satellites (constellation) that are sun synchronous with repeating ground ...
517 views

### Could a near earth asteroid perturb a satellite out of earth's orbit?

Given a satellite in GEO or a graveyard orbit, what characteristics of a passing NEO would be required to perturb said satellite out of Earth's influence and into a sun-bound or sun-centered highly ...
88 views

### GMAT Orbit Designer

I start to work with GMAT. I am looking into the API capabilites and I found several functions e.g. for the calculation of SSO Orbit Parameters, or Repeating Ground Tracks. So apart from this, is ...
109 views

### Impact Venus with Comet Leonard?

do we have the means to slightly alter Comet Leonard's trajectory so it impacts Venus instead of 'grazing' it in December 2021??
831 views

### Is there a neat formula for hyperbolic Kentucky windage?

When doing some back of a napkin calculations for a recent question Where would the Pascal B manhole cover be now?, I realised a quick way of solving these class of orbital mechanics question is to ...
325 views

### Where would the Pascal B manhole cover be now?

As part of the Operation Plumbbob series of nuclear tests, on August 27th, 1957, at 22:35 UT (15.35 Pacific Daylight Time), at the Nevada Test Range at 32°N 116°W, a 300 ton-yield atomic device was ...
15 views

### After inserting CAPSTONE into a "highly efficient ballistic lunar transfer trajectory" Lunar Photon; to what separate orbit for its safe disposal how?

NASA Ames's feature CAPSTONE’s CubeSat Prepares for Lunar Flight says CAPSTONE will use a hydrazine-fueled propulsion system during most of its three- to four- month journey to the Moon. This line of ...
74 views

### GMAT: Finite Burns commands in If statements inside For loops

Does anyone know why GMAT won't execute finite burns when the BeginFiniteBurn command is placed inside an If statement which is inside a For loop? I'm sure the If condition is verified because there ...
5k views

### What is the "mass" of a Lagrange point?

Of the five Lagrange points, L4 and L5, as stable points, can be orbited by asteroids, satellites, and any other useful or interesting object. Assuming two-body motion however, calculating orbits with ...
82 views

### How do orbits around Jacobi ellipsoids behave?

The Earth is a Maclaurin spheroid (aka. oblate). This affects orbits, most notably $J_2$ rotating the node line for inclined orbits, enabling thins like Sun-synchronous orbits. But the Maclourin ...
161 views

### Can mascons have Lagrange-like points? In principle? At the Moon?

Background Lagrange points are a mathematical consequence of the The Circular Restricted Three Body Problem (CR3BP or CRTBP); two massive bodies orbiting around their center of mass and a third ...
100 views

### How to calculate velocity vector in perifocal coordinates [closed]

Well the formula for it is here: Though if r is the radius and f is the true anomaly (which I assume is radians), then what is r dot and f dot respectively?
127 views

### Energy to "nudge" a planet to a smaller orbit

Suppose we wanted to move a mass-$m$ planet to a much smaller new orbit around our mass-$M$ Sun. We'll assume the initial and final orbits are circles of radii $r_i,\,r_f$ with $r_f\ll r_i$, so GPE is ...
73 views

### ISS Live Views of Earth on Nasa's EHDC Camera appear to be retrograde orbit

If the Orbit of the ISS is Prograde and Synchronized with the same orbit as the Earth, would not the Live EHDC views motion appear Stationary?
2k views

### Can an orbit rotate around a non-orthogonal axis?

I'll attempt to draw a mental example, in case images are not kind (if they are kind, you can likely skip this first paragraph). Let us say that the Earth is at it's aphelion (arbitrary choice), and ...
77 views

### How would you convert keplerian orbital elments into cartesain vectors with quaternions?

Coverting the keplerian elements to cartesain vectors ( posistion and velocity) is relatievly simple by using rotation matrices show in the document here: https://downloads.rene-schwarz.com/download/...
98 views

### Earth to Mars (or reverse) Hohmann transfer orbits for the 21st Century

Is anybody aware of a nice graphic showing for the next 20-30 years or maybe the rest of the 21st century, the time periods for Earth to Mars launches? They occur about every two years, but I'm ...
271 views

### Flyby puzzler; starting from Earth, how many times can you use Jupiter flybys in one century?

Is there any limit to how many times you can increase velocity by repeated sling shot manoeuvres? and its answers have got me thinking, and that's always dangerous. Suppose you have a durable RTG-...
79 views

### Calculating the time of flight between two anomalies gives a negative result?

I want to calculate the time of flight (TOF) between two true anomalies on an orbit with known orbital elements. Based on this wikipedia article and the post Time of flight between two anomalies in a ...
2k views

### Does going to Mars take the same energy as making a rendezvous with something going to Mars?

I think I found a mathematical error in the 2015 movie The Martian1. Warning, there will be spoilers. The final plan they settle on to rescue Mark Watney is to have the Tiayang Shen rendezvous with ...
The problem I'm trying to get a formula to calculate the state vectors $\vec{r}$ and $\vec{v} = \dot{\vec{r}}$ on an orbit, given a true anomaly $\nu$. I'm following the process described here : https:...