Questions tagged [space-travel]

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44 views

Dark energy as negative matter for Alcubierre drive

Can dark energy be used for the Alcubierre drive as a substitute for negative mass? After all, to make the Alcubierre drive work, it is necessary to expand the universe behind it, and that is what ...
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0answers
36 views

Can we travel to everywhere in two years? [duplicate]

I know that technology is far away from this but it is only a thought experiment. Assume that we could constantly accelerate with 1g (starting outside of the earth). Lightspeed is around 300 000 000 ...
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9 views

How exactly does a control moment gyroscope work?

I've searched a lot, but have not been able to find a proper explanation for the working of a control moment gyroscope. Could someone please explain it to me, preferably with vectors?
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1answer
12 views

Could light from the Sun be used to power the Breakthrough Starshot microships?

The Breakthrough Starshot initiative aims to accelerate a swarm of 16m$^2$-area solar sails to 15% of $c$ using Earth-based lasers in the order of 100GW power in 10 minute bursts. Considering loses ...
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4answers
10k views

Why don’t astronauts “push” spacecraft?

Perhaps it goes without saying, but according to Newton’s laws “every action has an equal and opposite reaction”. How do astronauts, especially those inside small spacecraft like the Crew Dragon, not “...
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2answers
60 views

How does a rocket slow down in space?

I’ve been reading about the conservation of momentum and its applications in deriving the rocket equation. I’m curious whether how can a rocket slow down in space. As far as i can comprehend, a rocket’...
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1answer
26 views

How close would a supernova be to endanger the astronauts on the ISS?

How close would a supernova be to endanger the astronauts on the ISS? Would Betelgeuse be close enough?
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1answer
48 views

Physics of Project Orion

I was reading the book "Project Orion" by George Dyson. For those who are unaware, Project Orion was basically a plan to launch a spaceship by flinging bombs out the rear and detonating them. The ...
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0answers
51 views

Is it possible to use the Sun's gravity to gain significant delta-v?

Someone asked here whether Sun's gravity has been used for delta-v gain, and from the answers it's not clear whether this is possible at all. There is this rule of thumb that "burning fuel inside a ...
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0answers
20 views

Travel Times in Various Metrics of Traversable Wormhole; A Requested Explanation

I understand Wormholes are theoretical, however, there are many, many articles written in relation to wormhole metrics and their associated qualities. 1) I have read the original MT-Wormhole paper ...
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2answers
56 views

Travelling in outerspace

Firstly, is it correct that for travel in outer space, the distance that can be travelled with a given amount of fuel is determined by the energy required to overcome the following forces: gravity ...
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0answers
71 views

Gravitational Slingshot

If a spacecraft slingshots around a planet P (with escape velocity $V$) at an angle $\theta$, I understand that the resulting velocity will be $$v_{2}=(v_{1}+2u)\sqrt{1-\frac{4uv_{1}(1-\cos\theta)}{(...
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1answer
118 views

From a traveler's point of view, what prevents him from reaching speed faster than light? [duplicate]

From a traveler's point of view, as he is accelerating with $1g$, in under one year he would reach the speed of light. Note that from his point of view, everything looks normal so he could keep ...
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0answers
21 views

Lisa Pathfinder Mission - interpretation of results (frequency)

In the results of the space mission Lisa Pathfinder is on the xx axis the frequency value. Where does this frequency come from? Does it come from satellite orbit frequency or mass vibration?
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31 views

Method adapted by ISRO

Why does the ISRO change orbits of a satellite in many steps? I've seen them do this in the MANGALYAAN as well as CHANDRAYAAN II missions. From what I understand, changing the orbit of the ...
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5answers
170 views

Constant $g$ acceleration from astronaut's frame of reference

When a spaceship is experiencing a constant acceleration of $10m/s^2$, the astronauts will be moving at nearly the speed of light after about a year in the earth's reference frame. This means the ...
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1answer
40 views

Do radioactive objects accelerate in space?

Americium tends to radiate mostly as alpha particles. It would seem to me that as particles irradiated away, they would transfer momentum and the object would accelerate in the opposite direction. If ...
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2answers
1k views

Spacetime and its contribution to space science

Does the launching of a satellite need the consideration of the general theory of relativity (GR)?
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0answers
51 views

Why can't we fly aeroplane or shuttle directly into the space (beyond 100 km height above Earth's surface)? [duplicate]

Without rockets can we go beyond Karmans line by shuttle or plane?
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0answers
13 views

How does a single satellite like the upcoming BIOMASS use interferometry?

The future satellite BIOMASS, from the ESA, will supposedly use p-band frequency interferometry to detect changes in forests. By itself? How?
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1answer
52 views

Free return trajectory versus burning rocket

It is said that Apollo was set to the free return trajectory while leaving earths gravity, heading to moon.Now the Free return trajectory is the one in which satellite uses moon gravity to return back ...
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2answers
141 views

Can we deorbit space trash into the sun by splitting it in two?

So there's an issue of deorbiting stuff because if you just deorbit it a little, it'll enter a more elliptical orbit but still hit you in the back when you return to this place a year later. Size and ...
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0answers
63 views

How to interpret doppler curve images of Chandrayaan-2 lander?

The frequency transmission data for Vikram, lander of Chandrayaan-2, received by 25 meter Dwingeloo radio telescope is plotted and tweeted by Cees Bassa. Kinks in the Doppler curve are interpreted as ...
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2answers
123 views

Simplified calculation of the amount of fuel required for a trip — are my calculations faulty?

I've been always fascinated with how easily scifi characters travel around the Solar system and sometimes the galaxy. They just hop into a spacecar and go wherever they want. So I've come up with a ...
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0answers
31 views

How to travel between two stationary worlds in the least amount of proper time?

I was intrigued by this question about minimizing the travel time between two worlds that are at rest with respect to each other, and disappointed that the answer turned out to be trivial. However, I ...
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4answers
3k views

How to travel between two stationary worlds in the least amount of time? (time dilation)

Let's imagine there are two, isolated, stationary worlds in space (called A and B), very far apart from each other. I live on World A, and some aliens live on World B. I want to learn about the ...
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1answer
70 views

Why don't spacecraft accelerate to the speed of light, or just fractionally below that?

In space there is almost nothing to slow you down, and your proppelent/S will always be traveling relatively faster than your craft so you should accelerate infinitely close to the speed of light ...
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1answer
39 views

Apparent temperature of the universe at relative speeds

Suppose you are in a vessel traveling at relativistic or near relativistic speed relative to your local galaxy--whatever is physically reasonable, and won't get rapidly torn apart by high energy ...
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0answers
35 views

What mechanism in the tidal effects around a black hole is it that destroys materia?

I just read this Quora question https://www.quora.com/Why-doesnt-NASA-send-a-probe-into-a-black-hole-to-learn-more and although the basic premises for the question are flawed (travel time is ...
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3answers
87 views

how do we navigate space without knowing the position of everything? wouldn't the gravity affect the sattelite/ship?

I tried looking for other questions but I couldn't find any. (if this is a duplicate, then I'm sorry, I just signed up, so I'm not sure what to search for) I was wondering, how do we navigate into ...
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1answer
45 views

How many orbits to catch up to ISS and Hubble?

To dock with orbiting satellites like the ISS or Hubble, how many orbits of earth do rockets and spacecraft clock up while they close in on their target satellite? Is the number highly variable ...
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1answer
46 views

I have a question about the gravity probe B geodectic precession formula and why it seems to be twice the planetary precession formula

Specifically, I can work out the planetary precession formula to give radians per orbit as 6*pi*GM/c^2r (and I find that on the web at places like http://farside.ph.utexas.edu/teaching/336k/...
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1answer
70 views

What determines the direction of an object that has undergone the effect of a gravitational slingshot?

I just started researching this topic and therefore I do not know much about it. Nonetheless, I am still curious about what determines the direction an object takes after passing by a planet. I think ...
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0answers
31 views

How is New Horizon able to send back data to Earth? [closed]

New Horizon is to send back images of Ultima Thule, 6.4 billion kilometres away. Barred having a very large power to send information back on a very large angle, it seems to me that the level of ...
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1answer
78 views

How can China put artificial moon if they're not in equator?

China plan to put artificial moon. I suppose the moon would have to be geo stationary in orbit. However, a geostationary orbit would be on equator and china is not on equator. So how would it work? ...
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1answer
36 views

Experiments in ISS

Recently a Japanese capsule brought back proteins that were created in ISS in the absence of gravity. Researchers will study them to "understand their folding better". My question is, regarding ...
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0answers
47 views

A question about almost stationary orbits

For an orbit around the earth with period equal to a sidereal day with eccentricity $e=0$ and inclination $i=0$, the path on earth would be a single point on the equator. I have done some simulations ...
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1answer
354 views

What is the minimum time required to travel 1 light-year from Earth and turn back? [duplicate]

Suppose I have a very powerful and durable rocket that is able to reach speed of light minus $10^{-1000^{1000^{1000}}}$ in $10^{-1000^{1000^{1000}}}$ milliseconds. Very instant acceleration. I can ...
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1answer
284 views

Is the Andromeda Milky Way collision the most likely form of intergalactic space travel?

Assuming that some form of sentient organization gradually spreads within the Milky Way through technology predicated on currently known physics, is the Andromeda-Milky Way collision in 4 billion ...
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2answers
58 views

What direction would an engine spin in space?

I am working on a science project in school with a friend on artificial gravity in space. We are both wondering if we could use normal electric motors, to let the outer ring move. Since there's no ...
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2answers
119 views

Delta-V of Earth to Moon mission using Moon orbit

I have read this article here and it talks about the delta-v cost of travelling to and from the Moon. Importantly it says that getting to an orbit round the Moon, and docking with a space station, and ...
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2answers
87 views

Parker Solar Probe top speed

All the news articles say it'll orbit the sun at 430,000 mph. How do they get that? It seems too low. Isn't orbital velocity proportional to $1/\sqrt{r}$? Parker will be 4 million miles above the "...
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1answer
48 views

Why are we using large chunks of copper to smash asteroids and comets? [closed]

Why is copper used? Isn't that expensive?
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6answers
7k views

Why put a radio telescope in space instead on the Moon?

Why are we not building a space-based radio telescope? If a lunar radio telescope is hard to build, why not a space-based radio telescope? It could be an interesting tool, I presume. Thus, what could ...
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3answers
50 views

Would it be possible to invert a tokamak to make a solar probe?

I was just browsing random stuff on the internet, and I came across this article about the parker solar probe. The rhetoric was like "oh my, the sun is so hot but the probe won't melt.. etc. etc.", ...
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3answers
175 views

Do any of our satellites or space exploration craft need or use relativity for strictly navigational purposes?

I thought I read somewhere that everything we've ever sent into space used only Newton for navigation, because relativistic effects are orders of magnitude smaller than other causes of course ...
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2answers
56 views

What are the options the human civilization will have before Sun gets brighter by 40% within next 3.5Billion years? [closed]

In next 3.5 Billion years, the sun will become 40% brighter, causing the oceans to dry up, and conditions for life sustainability shall become so critical that human must leave our solar system ( or ...
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2answers
93 views

Path to a distant star

Suppose we have a space ship that can go fast enough (0.9c) and we have plenty of time, and we want to travel to a star on the other side of the galaxy. How do you plot a path to navigate to that star?...
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1answer
5k views

Why is Anti-helium so important in the search for dark matter?

I've been reading/hearing that if the AMS satellite measures a significant flux of anti-helium in cosmic rays, that would be an irrefutable proof of dark matter. I was wondering: Why is that? what is ...

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