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93 votes
Accepted

Can I drive Elon Musk's Tesla after it's been in space for 100 Years?

Making a car run when it's been stored on Earth for 10 years can be a challenge. Storing it in space makes things worse. All lubricants will have evaporated. Cold welding is a possibility. The ...
Hobbes's user avatar
  • 128k
92 votes

How did people know how to build the first space ship?

This is a very broad question, but I'll take a stab at it. It was understood that gravity pulled the Earth into a spherical shape, with dense solids and liquids below less-dense gases, and it was ...
Russell Borogove's user avatar
92 votes
Accepted

Why do exploration spacecraft like Voyager 1 and 2 go through the asteroid belt, and not over or below it?

First, space is absolutely gigantic; the chance of either of the Voyagers, or ay other outer-planet mission, hitting an asteroid was infinitesimal. Second, the asteroid belt itself isn't really ...
Russell Borogove's user avatar
86 votes
Accepted

How was New Horizons able to direct data so precisely back to Earth?

The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°. As a practical example, this is more like ...
asdfex's user avatar
  • 15.1k
70 votes

Why do we not fly to space with helicopters? What are the practical altitude limits?

A 25m diameter rotor has a perimeter of around 78 meters. At that size, at 500rpm, the rotor tips would be going in excess of 1,400mph. At those kind of speeds, even though it doesn't take much power ...
jacksonj04's user avatar
67 votes

Why can't they just drop a solar winch down from a shuttle and have planes fly up and clip things on?

Because space isn't about going high; it's about going fast! For example, in a 400 km orbit (like ISS) you need a speed of about 27,500 km/h or 7.66 km per second. So if you would extend a ...
DarkDust's user avatar
  • 12.5k
63 votes
Accepted

Why is there a large wooden ball on Mariner 3's magnetometer?

I suspect the wooden sphere is a three-dimensional Helmholtz coil. A Helmholtz coil is a pair of circular coils, the radius of the coils should be equal to the distance of them. There is a coil pair ...
Uwe's user avatar
  • 49k
62 votes

How did people know how to build the first space ship?

One important note is that rocketry predates space travel - by a lot. The V-2 rocket christened "MW 18014", the very first suborbital flight, (meaning the rocket flew to space, but didn't go fast ...
Knetic's user avatar
  • 551
60 votes

Why do exploration spacecraft like Voyager 1 and 2 go through the asteroid belt, and not over or below it?

A Keplerian trajectory in the Solar system essentially needs to be in a plane defined by three points: the location of the Sun, the location you're starting from, and the point your target will be at ...
John Doty's user avatar
  • 3,364
59 votes

Why was Venus rather than Mars targeted for the first interplanetary landings?

The reason is delta-v, which is a crucial concept in Spaceflight. It means change in velocity, and is the primary 'currency' that space mission have to expend in order to reach places in the solar ...
Rikki-Tikki-Tavi's user avatar
59 votes
Accepted

Assuming a spacecraft is traveling in a constant rate and our Astronaut will exit it to a space walk, will she be "left behind" by the spacecraft?

As long as neither spacecraft nor the astronaut are accelerating or decelerating, the relative speed of the spacecraft and the astronaut remains the same. So the astronaut will hover near the ...
DarkDust's user avatar
  • 12.5k
55 votes

Why do we not fly to space with helicopters? What are the practical altitude limits?

At 100 km altitude, you get to the Karman line. This is the altitude where you have to fly at orbital speed to get sufficient lift. This definition is based on the lift equation, which applies to all ...
Hobbes's user avatar
  • 128k
55 votes
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If a spaceship ran out of fuel somewhere in space between Earth and Mars, does it slowly drift off to the Sun?

What you're missing is some combination of the following: objects launched from Earth orbit are still in orbit around the Sun, objects in orbit don't need fuel to stay in orbit. All the planets ...
userLTK's user avatar
  • 1,784
50 votes
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How does a space probe maintain its trajectory while passing through the extreme gravitational field of the gas giants of our solar system?

The trajectory was not only "unhindered" - it was enhanced! Knowing mass of the planet you can calculate very precisely how the trajectory of a probe flying by will be affected. You modify the ...
SF.'s user avatar
  • 55k
48 votes

Why wasn't the Mars Climate Orbiter's fatal error caught prior to launch?

NASA formed a board to investigate the loss of the spacecraft and reached some high level conclusions. The board cited a number of contributing factors, which I have filtered to include the ones most ...
GdD's user avatar
  • 20.3k
47 votes
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When will we send floating probes to Venus?

When will we send? We already did. In 1985 and 1986 the Soviet Union sent two Vega probes to Venus. Both included a robotic balloon (usually called aerobots). The two balloon aerobots were ...
Ginasius's user avatar
  • 920
46 votes

What are the chances that a spacecraft is hit by space junk?

Heh. So it turns out, figuring out the answer to this is precisely what I do for a living. The glib answer: it depends. It depends on how big an object you are worried about hitting. Are you worried ...
Tristan's user avatar
  • 17.3k
42 votes

During spacecraft reentry why is heatshield side down the most stable orientation?

We’re accustomed to seeing things travel pointy-end-first (bullets, rockets, arrows, Lamborghinis) so it seems “natural” that Entry Vehicles (EV) should be most stable traveling pointy-end-first as ...
Woody's user avatar
  • 22.1k
41 votes

If the Earth spun clockwise, how would that affect Space Exploration?

Primarily, locations of spaceports would change. California, not Florida would host the NASA's main launch site. Russia would be in slightly better position, able to send rockets over the Black Sea, ...
SF.'s user avatar
  • 55k
40 votes
Accepted

Puzzler - which spacecraft(s) incorporated real wood structural elements?

Rangers 3, 4, and 5 each had a seismometer encased in balsa wood to limit the impact loads.
Mark Adler's user avatar
  • 58.2k
40 votes
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Could a complex system of reaction wheels be used to propel a spacecraft?

Previously posted comments are correct: in free space (assumed free of any other bodies' gravity fields) there is no way to convert the reaction wheels' angular motion to translational motion. There ...
Tom Spilker's user avatar
  • 18.3k
39 votes
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Who navigates the ISS?

Most of the time, no one is piloting the ISS. In general, an object in orbit stays in the same orbit without needing to be propelled or piloted. At the relatively low altitude of the ISS's orbit, ...
Russell Borogove's user avatar
37 votes

Why was Venus rather than Mars targeted for the first interplanetary landings?

We didn't know how hostile Venus's surface was, until we had landed there. The atmosphere of Venus makes it easier to land there than Mars. From Wikipedia, we learn: Before radio observations in ...
PearsonArtPhoto's user avatar
  • 121k
37 votes
Accepted

Repurposing a nuclear submarine for space travel

NO A rocket can lift a few tons. A submarine weight thousands of tons. Propel itself in space: if you add an rocket or ion engine it could. But it's WAAAAY too heavy for any of theses to work. ...
Antzi's user avatar
  • 12.6k
37 votes
Accepted

Would a grinding machine be a simple and workable propulsion system for an interplanetary spacecraft?

The main engineering challenge in implementing your proposal is that in order to be competitive with a chemical rocket engine, the grinding wheel must rotate at an extremely high velocity. A typical ...
Thorondor's user avatar
  • 486
37 votes

What are the benefits of cryosleep?

NASA is working on a so-called 'Cryosleep Chamber', but why do they need it so badly? NASA does not "need it so badly". If it did "need it so badly", NASA would be spending tens to hundreds of ...
David Hammen's user avatar
37 votes

Is there any way that real stars would move like they do in the classic Windows 3.x screensaver if traveling through space at extreme speed?

I do disagree with the other answers, not on the result, but on the reason. You don't need to go faster than the speed of light to pass through multiple stars in a few seconds. Putting aside the ...
lvella's user avatar
  • 471
37 votes
Accepted

Orbital Supercomputer for Martian and Outer Planet Computing

They act as a massive supercomputer I think you massively underestimate how massive a massive supercomputer is, and most importantly, how massive both the power requirements and the cooling ...
Jörg W Mittag's user avatar
36 votes
Accepted

How does a Spacecraft change its orbit?

To answer your title question: By using its engines. However you seems to be quite puzzled by the fact that velocity of an object can decrease and increase over the course of an orbit. If the orbit ...
Antzi's user avatar
  • 12.6k
35 votes

When will we send floating probes to Venus?

Why are people so fascinated about Mars and not about Venus at all? The trivial answer - Mars is moderate place. A human could easily get around with a spacesuit, and it is trivial for robots and ...
Fattie's user avatar
  • 1,622

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