Questions tagged [space-travel]

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3answers
61 views

Questions on the notion of an inertial frame of reference

Imagine an astronaut flying in an spaceship at a constant speed in completely empty space, with no acceleration whatsoever, and no outside references, just dark empty space. Q: Can the astronaut tell ...
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1answer
160 views

The pioneer anomaly [closed]

The RTG's powering the electronics had to reject hundreds of watts of black body radiation to space. The RTG’s reflected a portion of their radiation onto the backside of the main paraboidal antenna, ...
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1answer
29 views

Energy distorting space

We know that mass distort space and time. Can energy do the same? How much heat will it take to create an observable effect? can we make a warp drive on that principle? By heating one end of a space ...
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1answer
72 views

Could you use a balloon to show the drag from the gas/atmosphere of something orbitting near the ISS?

If a balloon were floating next to the International Space Station (ISS), how big, light, and/or dense would it need to be such that the gas/atmosphere at that distance from the earth's surface would ...
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0answers
82 views

Why the Warp-drive uses a 3D shape to distort space instead of a 4D shape?

I know that warp-drives are just a theory and that they would require exotic mass (that is also a theoretical material), but, as said in this video, after some re-calculations, it was theorised that ...
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1answer
42 views

How would a neutral hydrogen gas interact with a relativistic spacecraft?

Inspired by a discussion from the comment thread of a gaming youtube video, I've been thinking about what kind of radiation environment a relativistic spacecraft would be exposed to as it passes ...
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1answer
67 views

Can civilizations orbiting black holes keep time with their interstellar travellers?

Due to relativistic-velocity interstellar travel time dilation, travellers would return in the far future of any civilization launching such an effort. A chart from wikipedia indicates typical time ...
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1answer
35 views

Wave drag in the interstellar medium

In Earth's atmosphere, an object moving at supersonic or near-supersonic speed experiences wave drag due to the formation of shock waves around the object's leading edge. At high speeds, wave drag is ...
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1answer
44 views

Accelerating a spaceship to near speed of light

Hypothetically, suppose we have the ability to accelerate a spaceship to near speed of light (lets say 0.9c). From what I remember of relativistic kinematics, the energy required to accelerate the ...
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1answer
39 views

Could cosmic rays be used for power on Mars?

Most studies of radiation levels of Mars that I can easily find focus on it as a hazard for potential human visitors. As such, a figure in rads or Sieverts is provided, which lumps together all of the ...
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2answers
72 views

Can we connect several Nano Spacecraft moving at 20% speed of light? [closed]

Nano spacecrafts are one gram silicon chips that will be accelerated to 20% of the speed of light to reach Alpha Centauri in 20 years. I wonder could we connect several spacecraft after they were ...
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1answer
34 views

What happens with trash that is left after a satellite expires?

I was reading an article that Japan is experimenting with wooden chassis for satellites so that they can keep the trash minimal. I was wondering if it was possible to design the satellites in a way ...
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3answers
4k views

“To come back to Earth…it can be five times the force of gravity” - video editor's mistake?

I've watched The Truth About Gravity With Professor Jim Al-Khalili | Gravity And Me | Spark where astronaut Chris Hadfield says at 3:55: To come back to Earth is violent Then after several seconds ...
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1answer
58 views

If 2 spaceships left Earth for the galactic centre, travelling near the speed of light, but they left an hour apart, would they arrive an hour apart?

If a spaceship left Earth for the galactic center at 3pm one day, traveling at extremely close to the speed of light (say 99.9999999%), then a second spaceship left at 4pm, would they arrive an hour ...
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0answers
128 views

At 50% c, I go party to IC1101 galaxy, and back home. How many times can i go before the expansion of the universe will lock me on one side?

Longer version of the question: Let's say I'm an immortal being (I could be artificial) going to "party" to IC1101, one of the biggest galaxies of the universe, 1 billion light-years away ...
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1answer
75 views

Voyager distance

This very nice NASA page continuously updates Voyager 1 & 2 distance away. How is that distance calculated/determined?
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1answer
102 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
14 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
14 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
138 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
31 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
60 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
53 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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2answers
57 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
90 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
143 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
34 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
183 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
43 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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1answer
72 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
161 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
67 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
130 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
71 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
40 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
36 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
95 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
48 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
49 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
73 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
79 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
37 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
48 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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