Questions tagged [orbital-mechanics]
Orbital mechanics (also called astrodynamics) is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft on an orbital or escape trajectory. For the movements of celestial bodies, use [celestial-mechanics], not this.
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Where is Lucy going? (asteroid mission)
On Halloween (31-Oct-2018) NASA Goddard announced that Lucy has a green light:
NASA’s Mission to Jupiter’s Trojans Given the Green Light for Development
All I have are these links which are now ...
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Use of thrusters for Collision Avoidance Maneuver
I'm building an orbit propagator that gives the position of two satellites at time T. The position are expressed in ECI and after that are being transformed in LVLH frame (as mentioned ECI to LVLH ...
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Which point in an orbiting body most closely follows its Keplerian trajectory?
Keplerian orbits can describe the motion of a negligible mass around a massive fixed central body, but they can also describe the motion of two bodies around their center of motion... with some ...
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Low-thrust spiraling to escape, is the flight path angle (gamma) at C3=0 always 39 degrees?
@MarkAdler's comment led me to ask Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver? which resulted in this tidy and efficient @MarkAdler answer which ...
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ECI to LVLH conversion
I want to transform the position and velocity of two satellites from ECI mean of date mean of equinox to LVLH(Local Vertical Local Horizontal). The problem is that there is little documentation that I ...
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Rotating in orbit?
Reading this question (Is the cupola, on the inside of the ISS, cold or warm to the touch?) prompted me to wonder about an object in orbit's orientation as it orbits its host object. For example, ...
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How to get true anomaly using subsatellite point (latitude)?
I am working on an application which is using an orbit propagator. I have a satellite which sets its latitude using this orbit propagator. I want to change the latitude of the satellite by a new value,...
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Help with my tensor tension; how to derive and calculate this rigid body gravity gradient torque?
Tensors make me tense.
Imagine a long thin rod in a circular orbit. The gravity gradient will produce a net torque on the rod whenever it is not oriented parallel, or perpendicular to the radius ...
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Computing the local orbital frame vector directions and angles of gyroscope direction in the satellite
In the context of the study of a cubesat (little satellite), I am asked to define the local orbital frame and compute the local orbital frame vector directions as a function of time (...
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NAIF and SpiceyPy returning seemingly inaccurate results
I am yet another amateur astrophysics enthusiast creating a solar system simulator. I began by hard-coding planetary bodies and their satellite orbiting characteristics via JPL data tables such as ...
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Why does the Juno spacecraft flyby Earth on the way to Jupiter?
Hohmann transfer to Jupiter is about 2 years 8 months. Juno spends 5 years getting there, almost twice as long. I note that it takes Juno 2 years 8 months to get to Jupiter after the Earth flyby, does ...
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What could a High Earth Orbit be used for in practice?
I was perusing wikipedia and saw this awesome infographic:
Original location of infograhpic: Wikipedia
Then it hit me, in all the time I've been browsing space articles and such...
I've never ...
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Is the equation showed below the right one for an airplane flying at the Kármán line altitude?
$$\frac{GM_Em}{(R + h)^2} - \frac{ \rho v^2 S C_L}{2} = \frac{mv^2}{R + h}$$
$GM_E$ is Earth's standard gravitational parameter ,
$R$ is Earth's radius and $h$ the altitude of the airplane above the ...
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How will JWST maintain its elliptical orbit around L2?
I understand that JWST will have a vertical elliptical orbit around L2, but what I don't understand is how the telescope will actually maintain an orbit if there is no body in L2 to actually orbit ...
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Why would the orbit of a satellite in GEO climb by 21 km in altitude over six months by itself?
This answer mentions several effects that tend to move geostationary satellites out of their "box" over time, but one really surprised me.
According to the plot below (from there, but ...
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How stationary is geostationary?
When a satellite is in geostationary orbit, it is supposed to stay above one spot of the earth and rotate around the earth at the same rate the earth spins. But how exact does that equality need to be?...
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Could the $C_L$ of the X-15 be calculated from the flight data near the Kármán line altitude?
The "lift coefficient" $C_L$ can be very different for one specific aircraft at different speeds.
According to this article from NASA about the lift coefficient:
So it is completely incorrect to ...
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Does an airplane in orbit near the Kármán line altitude, with the air providing lift, ever reach orbital velocity? [duplicate]
The equation for an airplane in orbit with the air providing lift would be:
$$\frac{GM_Em}{(R+h)^2} - \frac{\rho(h) v^2 S C_L}{2} = \frac{mv^2}{R+h} $$
$GM_E$ is Earth's standard gravitational ...
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Would the barycenter in a binary star system be ideal for a space habitat?
I was reading about binary star systems and saw a bunch of diagrams, mainly the following:
Would there be benefits to creating a space station in the center of two binary rotating bodies? Would it be ...
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Where does the definition of the Kármán line on Wikipedia come from?
According to Wikipedia's article about the Kármán line:
The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity ( ...
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How do long range space probes adjust trajectory?
More specifically, after the main launch adjustments have been made using the primary boosters and temporary adjusting propellants how might even the slightest trajectory and orientation corrections ...
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How (the heck) can 2014 MU69's orbit be know well enough for a close flyby by New Horizons?
The object 2014 MU69 is much smaller and dimmer than Pluto. Even as New Horizons approaches, it will be much harder for its 8.2 inch aperture, cooled CCD long range imager LORRI to get a fix on it ...
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Timing shadows from the Kuiper belt! Any news? Did it work?
update 24-Jun-2017: SOFIA Arrives in New Zealand to Observe Southern Skies There are plans to fly SOFIA through another predicted occultation path on July 17. SOFIA is a huge (2.5 meter dia.) infrared ...
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Delta-v to move from GEO to GEO
To move a satellite in geostationary orbit, 166°55′E, to the antipode, 13° 4' 3.2" W, what delta-V would be needed for this to be accomplished?
As for time constraints, I do not know what are the ...
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Deviation of semi-major axis
If I calculate the semi-major axis of Molniya-1T with
$a = \sqrt[3]{\dfrac{GM}{n^2}}$ with $n=3.18683728\text{ }d^{-1}$, I get another apoapsis ($a=19505.7$ km) as noted at Heavens Above:
apogee ...
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Is it correct to apply the vis-viva equation to an airplane that flies in a straight line at the Kármán line?
The vis-viva equation models the motion of an orbiting body and it applies when the only force acting on the body is it's own weight.
So is it correct to apply this equation to an airplane that ...
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How much delta-v is expended to get <out of the atmosphere>
How much delta-v it's spent in getting up to avoid the air drag once in orbit?
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Does a credible Kármán plane reach escape velocity within 1 minute or does it follow the curvature of the Earth? [duplicate]
Edit: This question is no duplicate because here the dropping of the atmospheric density together with the horizontal line, play an important role.
Furthermore none of the answers and question ...
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Simulating a nanosatellite lunar flyby
I am trying to create a Lunar Flyby mission for small nanosatellites and I want to plot an orbit for it. The problem is that no website has proper information as to what variables, problems and ...
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Could a ball of water stay in orbit?
Could a water bubble (spherical occlusion of water in air or vacuum) similar to the one in the picture below remain in Earth orbit without evaporating, dispersing, or disintegrating? Assume the orbit ...
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Is it correct to use the vis-viva equation when there are two forces acting on the orbiting body? [closed]
Edit: Although this question seems similar to the question "Is it correct to apply the vis-viva equation to an airplane that flies in a straight line", it is different because there the airplane flies ...
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Spiraling out from circular orbit to escape via low thrust, what is γ (gamma)?
@MarkAdler's comment led me to ask Why would a slow spiral from a C3 of zero take about 2.4 times as much ΔV as an impulsive maneuver? which resulted in this tidy and efficient @MarkAdler answer which ...
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Game for teaching basics of orbital mechanics
I am looking for a game that would be suitable for teaching basic orbital mechanics concepts to primary school students (grades 6-8). Contrary to most of the questions here asking about spaceflight ...
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Calculating velocity state vector with orbital elements in 2D
I'm writing a little project that simulates an orbit by converting from initial state vectors $\vec{r}$ and $\vec{v}$ to Keplerian elements, then converting back to $\vec{r}$ and $\vec{v}$ from those ...
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How much does the tidal effect affect satellites in a retrograde orbit?
How much more unstable are satellites in retrograde then a pro-grade orbit? Does the stability of a retrograde orbit increase with altitude?
This answer said this orbit is unstable and made me think,...
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The Orbital Mass Accelerator Engine Theory
Can 2 satellites equal in weight traveling on the same orbital path in the opposite directions intersect and propel each other to gain altitude in orbit?
Can orbital perturbation be negated during ...
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How would propagation differ between a GEO and a Retrograde GEO?
A Binary Equatorial Synchronous Retrograde Orbit is an orbit that would travel in the opposite direction of GEO and would pass over the same point on Earth twice per day at the same altitude of GEO. ...
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Is it possible for amateurs to determine the orbit of satellites
Maybe some people urge this is a DIY site question but i thought here is the proper place to ask this question.
Is it possible for amateurs like students with commercial and available equipment like ...
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Why does a gravity capture require a loss of velocity?
I've read a gravity capture of an object requires the captured object to lose velocity by some means (impact, third body tidal force, etc).
Is there not a possible encounter that happens at a low ...
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How presise could 2 satellites "thread the needle" in orbit?
I have a question about using a magnetic field to propel 2 satellites off each other while traveling in opposite directions on the same orbital plain to intersect either 2:1 or 1:1 on each orbit ...
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How fast are trips to the Moon for unmanned spacecraft typically?
The period of an orbit around the Earth is given by:
$$T = 2 \pi \sqrt{a^3/GM}$$
For Earth GM is about 3.986E+14 m^3/s^2. Put in $a$ = ((6378+400)*1000) for the ISS in LEO (as a test) and you get ...
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Launch Vehicle LM2D
As it is well known, the circularization of orbits needs at least 3 stages.
How could the Chinese launch vehicle LM2D circularizes its orbit with only 2 stages?
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Would the orbits intersect during 7 days?
I'm calculating the probability of collision of the satellites. I'm trying to filter the set of orbits to minimize the calculations.
Which conditions may definitely say that the given 2 orbits ...
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Calculating the radial, in-track and cross-track distances
I'm computing the relative distances between satellites.
The following picture shows the distances, which are considered as risky.
What do Radial, In-track and Cross-track mean and why are they ...
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What are these orientations called in orbit?
Let's say a spacecraft is in an orbit like this one:
If the red arrows point to prograde and retrograde, and the blue arrows point to normal and antinormal, what do the green arrows point to?
In ...
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How do you find lunar flyby using Apollo 13 mission report data?
Link to mission report: https://www.hq.nasa.gov/alsj/a13/A13_MissionReport.pdf
So Im trying to do analysis on the mission phases of Apollo 13 but my part is to only focus on the flyby part. My ...
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How long does a CubeSat last?
If I were to launch a CubeSat, how long would it last before falling out of orbit and burning up in the atmosphere?
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How does a Mars lander reach a chosen landing site?
I see lots of questions how landing sites are chosen, but none so far how these landing sites are reached.
It already looks like magic how the target planet can be reached at all, but when are ...
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General expression describing the trajectory of a bullet in orbit - fired in an arbitrary direction (version 2)
This replaces a previous similar question that I could have formulated better.
I'm in orbit and I fire a bullet in an arbitrary direction.
I could shoot
(1) Along the direction of the orbit ...
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What is the darkest orbit around Earth?
What orbits around Earth has the least and most sun light exposure?
I wondered: When taking pictures either of Earth or otherwise with various telescopes in orbit, does it help to be in Earth's ...