Questions tagged [trajectory]

Questions regarding the path that a spacecraft will take due to forces acting on the spacecraft, such as gravitational or radiation from the sun.

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Without the accident, would Apollo 13 still have been the farthest crewed mission from the Earth?

This answer notes that the Apollo 13 crew holds the record for the distance that humans have traveled beyond Earth. Had the mission exactly followed the flight plan, would they still have been the ...
DrSheldon's user avatar
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38 votes
3 answers
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What is the feasibility of launching a probe to Sedna?

This dwarf planet reaches perihelion in the summer of 2076. At a distance of 76 au, is it feasible to launch a probe that would reach Sedna in time? With an orbital period of over 11,000 years, this ...
Jerard Puckett's user avatar
30 votes
5 answers
6k views

Do any launches bypass LEO?

If sending a payload to GEO (geosynchronous orbit) or any other high orbit, you could start off launching to LEO (low Earth orbit), and then use a Hohmann transfer to raise the height of the orbit. I ...
AlanSE's user avatar
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29 votes
9 answers
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Could an astronaut safely shoot the Sun with a gun?

I'm rather skeptical of this comic: I think a bullet's speed is insignificant to the orbital speed around the Sun, but is such possible without the astronaut falling into the Sun? Maybe with an ...
Cees Timmerman's user avatar
27 votes
3 answers
2k views

If I wanted to reconstruct an entire Apollo mission's crewed spacecraft trajectories, what are the key sources of historical data I'd look for?

The last few images in Robert A. Braeunig's Apollo 11's Translunar Trajectory; and how they avoided the heart of the radiation belts are fascinating and a bit perplexing as discussed in this answer ...
uhoh's user avatar
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25 votes
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Why don't we know exactly where the Chinese rocket will fall?

China has launched another Long March 5B rocket that seems liable to fall anywhere Although the overall risk of harm to people is low—there is only a 0.5 percent chance of injury or death to a human, ...
Machavity's user avatar
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25 votes
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Why will JUICE take 8 years to reach Jupiter, longer than any earlier spacecraft?

Galileo took six years from Earth to Jupiter. Cassini-Huygens took three years to reach Jupiter and six years to reach Saturn. New Horizons took one year to reach Jupiter. Juno was launched in 2011 ...
gerrit's user avatar
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24 votes
1 answer
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How are flight plans calculated?

When a project like Rosetta is being developed, how are flight plans calculated? Do planners simply input the desired target into a program or a flight computer which spits out the optimum flight path ...
coleopterist's user avatar
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21 votes
4 answers
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Has Luna been used for gravity assist for interplanetary probes?

The Earth's natural satellite has a great deal of angular momentum that seems to me could be used to derive a considerable boost for leaving the local SOI. Has any probe used a Lunar flyby as part of ...
Jerard Puckett's user avatar
18 votes
4 answers
3k views

Can we set up an orbiting transporter between Earth and the Moon?

I will give an example with the moon. If some spacecraft is put either in orbit around both earth and moon or in highly eccentric orbit that intersects with the moon orbit, some other spacecraft can ...
Nikolai Frolov's user avatar
18 votes
5 answers
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Would leaving the ecliptic plane offer any benefit to interstellar travel?

Aside from the obvious answer of being able to easily avoid the larger bodies in the Solar System. I'm primarily curious as to the mechanics of this endeavor -- would there be any benefit to ...
Anthony Neace's user avatar
18 votes
2 answers
2k views

Traveling through the asteriod belt?

The question What's the (particle) density of the asteroid belt? is about the density of objects in the asteroid belt. As a follow up related question and what I am interested in: When we send ...
Muze's user avatar
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18 votes
1 answer
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In deep space missions, how much of the journey is pre-programmed and how much is "direct" control?

Regarding deep space missions, like the Rosetta mission, how much of the journey to the final destination is pre-programmed vs. recalculated on the fly? For the Rosetta example, was the whole sequence ...
zegkljan's user avatar
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17 votes
5 answers
5k views

Why are all trajectories in space a conic sections?

All trajectories available in space: circle, ellipse, parabola, hyperbola, straight line are parts of cone. Why? Does the spacetime have a conic shape?
Robotex's user avatar
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2 answers
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Is 678 km the new altitude record for a rocket shot "straight up" (vertical launch)?

The Space Daily April 10th Rocket Science item Europe's largest sounding rocket launched from Esrange says: MAXUS 9, Europe's largest sounding rocket for experiments in microgravity, successfully ...
uhoh's user avatar
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17 votes
1 answer
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Why is Artemis 1 swinging well out of the plane of the moon's orbit on its return to Earth?

According to the 3-D model of the Artemis 1 mission (click on the "Mission View" button and use the slider to zoom out a bit), the outbound trip was close to the plane of the moon's orbit, ...
Dave Tweed's user avatar
16 votes
3 answers
1k views

The Russians recently tested a new launch trajectory that goes to the space station in about six hours. What allowed for the difference?

According to this article, Russia recently tested a new launch trajectory that shaved over 45 hours off their normal flight time. What allowed for this difference? Doesn't it seem like the shortest ...
user avatar
16 votes
4 answers
3k views

How much reentry speed did the Shuttles shed by doing a series of sharp turns?

Jerard Puckett mentioned in The Pod Bay yesterday that Shuttles did S-Curve maneuvers back and forth across their reentry trajectory to shed speed. After a bit of looking, I found some reference to ...
kim holder's user avatar
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16 votes
2 answers
4k views

Space travel using constant acceleration drive: Earth to Europa

Long story short: I'm writing sci-fi and taking my protagonist to Europa. He's got 2 weeks to one month to get there from Earth, give or take a few days. That sounds, of course, preposterous in this ...
adamholtwrites's user avatar
16 votes
3 answers
11k views

How can Artemis 1 take so much longer for Earth-Lunar transit than the Apollo missions did?

The Artemis I mission will take 8-14 days to get from Earth to the Moon. Apollo 11 only took 3 days. Similarly the return will be 9-19 days for Artemis I and just over 2 days for Apollo 11. Why is the ...
Ludo's user avatar
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16 votes
2 answers
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What software can be used to determine deep-space trajectories?

In What are the choices today for orbital mechanics simulation software?, an entire range of software was listed for many platforms. I'd like to narrow this down a bit. Specifically, two questions: ...
Jerard Puckett's user avatar
15 votes
2 answers
2k views

How do the interferometers on the drag-free satellite LISA receive power without altering their geodesic trajectory?

LISA is a proposed space probe designed to measure gravitational waves. It aims to measure gravitational waves directly by using laser interferometry. It uses a drag-free satellite design to protect ...
Woody's user avatar
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15 votes
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What is the reason for the Ariane 5 launcher with Intelsat 29e losing altitude?

After reaching a peak altitude of 222 km the Ariane 5 launcher with Intelsat 29e starts to lose altitude. What is the reason for this trajectory? Youtube video Paper on Ariane 5
SE - stop firing the good guys's user avatar
15 votes
3 answers
1k views

Gravity assist for manned travel

Since we already use gravity assist to launch satellites through the solar system, is there any way we can use gravity assist to speed up a manned trip to a planet such as Titan or Europa, while also ...
matthew spear's user avatar
15 votes
2 answers
4k views

What did I see just before the ISS but on a different trajectory?

I live at 49.99N, 8.57E. Today we had exceptionally clear skies. I was looking out a window towards the South between 7:48pm and 7:52pm local time (central european) when I noticed a strange light ...
8192K's user avatar
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15 votes
3 answers
2k views

Can someone give me a 'trajectory optimisation for dummies' answer?

So, I am currently doing a project on trajectory optimisation. I get the principle of it, minimise fuel cost for a journey, or try to maximise the spacecraft weight at target destination, and that ...
Harvey Rael's user avatar
15 votes
3 answers
2k views

Puzzler: Precisely what maximum distance from the Earth did the Apollo 13 astronauts achieve?

tl;dr: Both this answer to Which astronaut travelled farthest from Earth? this answer to How far have astronauts been in space? quote Wikipedia to state that the Apollo 13 astronauts reached 400,171 ...
uhoh's user avatar
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14 votes
1 answer
2k views

How to choose the best direction to leave Earth's sphere of influence?

What direction is optimal for spacecraft to leave Earth's sphere of influence (SOI) when it's going to an outer or inner planet? Let's presume that we have a spacecraft in a circular LEO (ecc=0.0). ...
Даниил Галахов's user avatar
14 votes
2 answers
2k views

If something "falls off" the L2 or L1 point, where will it go?

The L1 and L2 points are thought to be unstable "saddle" points, meaning that there is stability in two directions of movement, but not in the other. That raises an obvious question - when a ...
AlanSE's user avatar
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14 votes
1 answer
277 views

Explanation of single-burn trajectories from Lunar surface to Earth surface

I learned of the fine book Soviet Robots in the Solar System from this excellent answer. One chapter in it describes how the Soviets had extreme mass limitations on their lunar sample return vehicle ...
Organic Marble's user avatar
13 votes
5 answers
2k views

What's the best flightpath to get to Sedna by 2076?

Repeated Google searches over the past year, as well as recent searches of NTRS, AIAA, and arXiv, show no signs that anyone has seriously considered a mission to Sedna. I would like to propose a ...
Jerard Puckett's user avatar
13 votes
4 answers
1k views

What is the least energetic trajectory design to send uncrewed supplies to Mars?

Both Mars One and NASA have suggested sending uncrewed supply ships to Mars as part of a manned mission or colonization. These payloads can take all the time they like, not being constrained by human ...
Jerard Puckett's user avatar
13 votes
2 answers
8k views

Why don't we take the shortest route to Mars?

As far as i understand we are going on a route shown in the picture. When we can actually let Mars do the travelling for us and just take the short route and wait for Mars to arrive... Won't that be ...
Steven Lebègue's user avatar
13 votes
2 answers
2k views

Is it possible to "map" the Interplanetary Transport Network?

Cartographers have always been valued members of any exploration team. Even the teenage George Washington had experience with the "compass and chain." Every Terra Incognito is in need of a good map. ...
Jerard Puckett's user avatar
13 votes
1 answer
2k views

Climbing at terminal velocity minimizes losses? But why? And "of what"?

A lucky discovery of a Kerbal engineer's writing gave this deep insight into the mechanics of climbing to orbit: the best way to minimize d/v losses through the atmosphere is to always go at ...
AlanSE's user avatar
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13 votes
1 answer
2k views

What will happen to Parker Solar Probe in the long term?

Will the probe be intentionally crashed anywhere? Or is keeping space decontaminated not an issue here since temperature and radiation will sterilize anything in that kind of orbit?
Everyday Astronaut's user avatar
13 votes
1 answer
2k views

How accurate are modern ephemerides, and how does their accuracy degrade over time?

I was reading about what is involved in making an ephemeris and wondered about this. Feeling I'd read pieces that extrapolated orbits over many thousands of years, I looked for an example and found ...
kim holder's user avatar
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13 votes
1 answer
2k views

What does the BackFlip lunar cycler do in its pass by Earth?

This paper describes an Earth-moon cycler orbit. In this concept, a 180 degree "BackFlip" is used to modify a more simple cycler orbit. However, I can't figure out what cycler orbit it modifies, and ...
AlanSE's user avatar
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12 votes
4 answers
6k views

Did any spacecraft ever use the Sun's gravity for acceleration?

Space probes often use planets to accelerate onto a trajectory towards their goal(s) without having to consume too much fuel. But the fastest acceleration would be made through the Sun's gravity if ...
user avatar
12 votes
2 answers
3k views

Can the Falcon Heavy handle deep space missions?

Can the Falcon Heavy rocket handle sending payloads past Jupiter like the Atlas V?
CBredlow's user avatar
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12 votes
5 answers
6k views

Mathematics used for SpaceX first stage re-entry burn guidance?

I thought it would be fun to make a basic simulation of a first-stage fly-back of SpaceX's Falcon 9, but was wondering what mathematics is used to perform something like this. Looking at this page: ...
InquisitiveInquirer's user avatar
12 votes
1 answer
29k views

Current position of Starman

Have looked at current videos of Starman and not found data as to it's current position. Is there a site plotting the current position of Starman?
Ted Lawson's user avatar
11 votes
6 answers
3k views

Has any space probe changed course (in a large way) over time?

I encountered the following text from here: Generally, a spacecraft is launched with huge rockets into a certain trajectory, or path, and it continues on that that path. Often the smaller rockets ...
Nilay Ghosh's user avatar
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11 votes
3 answers
2k views

Physics and math behind flight through solar system [closed]

I wrote a program that simulates a solar system. I was able to calculate the locations for every planet on its elliptical route for any given time. In a second project, I managed to simulate newtonian ...
joe's user avatar
  • 373
11 votes
1 answer
3k views

How far around the world does a rocket travel before it enters orbit?

If a rocket launches from Florida, how far around the world does it travel before it reaches orbit? Is it in space before it completes crossing the Atlantic? Does it vary for different powered ...
Dan Sorensen's user avatar
  • 3,561
11 votes
1 answer
745 views

Ephemeris data usage in interplanetary trajectory application

I'm trying to write a Mathematica application that allows users to choose their date of departure and time-of-flight for an interplanetary transfer mission (currently only working for Earth-Mars ...
InquisitiveInquirer's user avatar
11 votes
1 answer
422 views

Are any spacecraft heading remotely where Planet 9 is expected to be?

Planet 9, the hypothetical planet predicted Batygin and Brown, is expected to have an apoasis near the galactic center. Is there a spacecraft that is heading in that direction? Specifically, they ...
PearsonArtPhoto's user avatar
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11 votes
1 answer
2k views

Improvements to script for Finite Burn Trajectory Optimization with MATLAB

I've written a MATLAB script to use the bvp4c two point boundary equation solver to implement a Calculus of Variations trajectory optimization of the problem of a single finite burn with a free coast ...
lamont's user avatar
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10 votes
6 answers
719 views

How was Juno's arrival set up to be on the evening of July 4th?

Presumable it is largely a coincidence that Juno arrives at the perfect moment for American pride in NASA's achievements, but not entirely. The video below of the trajectory, released in July 2011 ...
kim holder's user avatar
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10 votes
1 answer
2k views

Is this plot of deep space trajectories correct? Did most launch retrograde from Earth? Why do some change direction between planets?

This answer contains some nice plots of deep space spacecraft trajectories. Noticing that Voyage 2's heliocentric velocity dropped substantially just before 1990 I wanted to see why. Wikipedia's ...
uhoh's user avatar
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