Questions tagged [velocity]
Questions about the distance objects or gases cover in a fixed amount of time while traveling in space, being launched or descending. Also for questions about speed-comparisons.
78 questions
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Which speed did already functional plasma engine satellites/probes reach?
According to this, Russia Claims New Plasma-Based Engine Could Cut Mars Travel to Just 30 Days Using regular fuel combustion, rockets have a maximum matter flow velocity of roughly 2.7 miles per ...
- 1,689
3votes
1answer
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Calculating the ideal characteristic velocity for hydrazine and nitrogen tetroxide
I'm trying to understand how to calculate the ideal characteristic velocity for hydrazine (HYD) and nitrogen tetroxide (NTO). I believe that the following formula is the correct one to use: $$c^{*}=\...
- 131
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2answers
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How can I visualize the movement of a solar sail?
I am a physics teacher in an elementary school. Together with a student we started to investigate the motion of a solar sail. It shall be of 81 m² in size and 16 kg in mass around the sun at a ...
18votes
2answers
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Every day, how much speed does Voyager lose due to the sun's gravity?
The Voyager spacecraft will never be pulled back into the sun because it achieved escape velocity. But it's moving away slower and slower all the time. Voyager is currently moving away from us at 31,...
5votes
1answer
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How quickly could a probe reach the heliopause?
What if the goal of the Voyager program was instead to reach the edge of the heliosphere (effectively, interstellar space) within a decade? What would be the amount of fuel required and is this amount ...
3votes
2answers
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How long would a space tether on Phobos need to be to exceed earth's escape velocity?
Many futurists and science-fiction enthusiasts talk about one day building a space tether anchored to Mars' moon Phobos, extending 6,000 kilometres from the moon to Mars' lower atmosphere, and usually ...
3votes
1answer
173views
The accuracy of the formula that I created
$$ F = \frac{2RSA}{c} \sin^2 \theta $$ $$ F = am \ \ ↔ \ \ a = \frac{F}{m} $$ $$ S(r) = \frac{L}{4 \pi r^2c} $$ $$ \begin{align} a(r) & = \frac{F(r)}{m} \\ & = \frac{2RS(r)A}{mc} \sin^2 \...
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1answer
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What is the terminal velocity of the Falcon 9 at sea level (on Earth)?
What is the terminal velocity of the Falcon 9 at sea level (on Earth)? Has SpaceX released enough information that this could be calculated with reasonable accuracy? Assume that the Falcon 9 is ...
4votes
1answer
186views
What's the lowest altitude that can be reached only at orbital velocity?
The higher altitude you wanna reach the more delta-v you need. E.g. the SpaceShipTwo never went higher than 90 km (56 mi), so it could fly well below even 1/10th of orbital speed. However, at some ...
- 315
6votes
3answers
490views
Satellite slew rate with respect to a ground station
For a given satellite orbit and observation time, I have the vectors containing the elevation and azimuth angles of the satellite with respect to a ground station. I know that the elevation slew rate ...
- 63
1vote
2answers
343views
What can possibly accelerate space elevator to these types of extreme velocities?
Is it possible for a space elevator not to just reach speeds of a few hundred km/h, but much faster. Since in the future, people might want to go up to GEO to maybe work there and come back home on ...
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Calculate velocity vector of elliptical orbit given the position vector at that point, the instantaneous speed, the true anomaly, and the inclination?
Sorry if this is obvious, but I am an amateur at orbital mechanics and trigonometry was never my strong suit. I would like to calculate the velocity vector at a point in an orbit given: position ...
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10votes
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What's the motion of two connected satellites orbiting the Earth after their separation?
Let's consider the following problem (it's a job interview question): two satellites are orbiting the Earth in a circular orbit; they are rigidly linked by a tether which is always pointing in the ...
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5answers
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Is the launch of a rocket slow because the change in velocity (delta_v) should be as small as possible because of energetic reasons?
Does it make sense to keep the launch of a rocket slow because the change in velocity (a.k.a. delta_v) should be as small as possible because of energetic reasons?
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1answer
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Higher nozzle exit velocity generally means higher thrust right?
Higher nozzle exit velocity generally means higher thrust right? If that is the case, then a higher heat capacity could potentially lead to a higher exit velocity, thus higher thrust?
