Colloquially referred to as one of the hardest professions, rocket science is actually a common name for spacecraft/space-systems engineering. However, one can also generalize this to include all forms of rocketry, including rockets that are not capable of space travel.
Questions tagged [rocket-science]
800 questions
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Why do spaceships heat up when entering earth but not when exiting?
Recently I read up on spacecrafts entering earth using a heat shield. However, when exiting the Earth's atmosphere, it does not heat up, so it does not need a heat shield at that point of time yet. Why is this so? I know then when entering earth,…
QuIcKmAtHs
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Could we send a man safely to the Moon in a rocket without knowledge of general relativity?
I'm wondering if it's possible to send a man to the Moon using equations consistent with Newtonian gravity and without the elaborate tools of Einstein gravity. Are the predictions made by Newtonian gravity sufficiently precise to plan a successful…
Dargscisyhp
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Why are rockets so big?
I'm curious why rockets are so big in their size. Since both the gravitational potential one need to overcome in order to put thing into orbit, and the chemical energy burned from the fuel, are proportional to the mass, so if we shrink the rocket…
xslittlegrass
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How long would it take me to travel to a distant star?
Suppose I wanted to travel to one of the recently discovered potentially Earth-like planets such as Kepler 186f that is 490 light years away. Assuming I had a powerful rocket and enough fuel, how long would it take me?
John Rennie
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Why do rocket engines have a throat?
Diagrams of rocket engines like this one,
(source)
always seem to show a combustion chamber with a throat, followed by a nozzle.
Why is there a throat? Wouldn't the thrust be the same if the whole engine was a U-shaped combustion chamber with a…
Jens
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What is the possibility of a railgun assisted orbital launch?
Basic facts: The world's deepest mine is 2.4 miles deep. Railguns can acheive a muzzle velocity of a projectile on the order of 7.5 km/s. The Earth's escape velocity is 11.2 km/s.
It seems to me that a railgun style launch device built into a deep…
AdamRedwine
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Can you exit the event horizon with a rocket?
The reason given in most places about why one cannot escape out from an event horizon is the fact that the escape velocity at the event horizon is equal to the speed of light, and no one can go faster than speed of light.
But, you don't really need…
Lahiru Chandima
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Where does the extra kinetic energy of the rocket come from?
Consider a rocket in deep space with no external forces. Using the formula for linear kinetic energy
$$\text{KE} = mv^2/2$$
we find that adding $100\ \text{m/s}$ while initially travelling at $1000\ \text{m/s}$ will add a great deal more energy to…
Nomoturtle
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Supergun Launching of Satellites
I should say first that I don't believe this is a feasible launch method, otherwise NASA and other space agencies would be using it by now.
It's based on this BBC news story Saddam Hussein's Supergun but, luckily this monstrosity was never…
user108787
39
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Why don't modern spacecraft use nuclear power?
The Voyager 1 & 2 spacecraft launched in 1977 with Plutonium as their source of electricity. 34 years later they claim these two spacecraft have enough power to last them until at least 2020. That means they'll have had enough power to last them at…
John Conde
36
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Second law of Newton for variable mass systems
Frequently I see the expression
$$F = \frac{dp}{dt} = \frac{d}{dt}(mv) = \frac{dm}{dt}v + ma,$$
which can be applied to variable mass systems.
But I'm wondering if this derivation is correct, because the second law of Newton is formulated for point…
yarnamc
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Why is the work done by a rocket engine greater at higher speeds?
From this comment by orlp:
If I strap a rocket booster to a rocket in space and fire it for one second, then the work provided is much higher when the rocket is flying fast compared to when the rocket was stationary. In both cases the rocket fires…
Pilchard123
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Using nuclear devices to terraform Mars: Elon Musk's nuclear proposal?
Elon Musk has recently suggested Using nuclear devices to terraform Mars. In the past, comet related ideas were mooted, but Musk seems, to me anyway, to be a man in a hurry and perhaps his idea has some merit, as waiting around for suitable comets…
user81619
31
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Why does it take so long to get to the ISS?
I don't understand why when first launched Space X's Dragon capsule had to orbit the Earth many times in order to match up with the ISS? Was this purely to match it's speed, or to get closer (as in altitude) to the ISS?
In the stages when it gets to…
Jonathan.
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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 “push” the spacecraft when they bounce and push…
