It already is being used for military purposes right now as in spy satellites. Even very recently SpaceX was tasked to launch a U.S. spy satellite into orbit but it exploded and the satellite didn’t make it.
In 1984 a Titan 34D rocket launched the KH-9 and KH-11 satellites for “reconnaissance,” and the DSP-2-6R satellite for missile detection. The list just starts there and goes into the hundreds including many intelligence-gatheringsatellites and so on.
And, by the way, not just by the United States, but other governments as well.
Furthermore, the Chinese government once shot a missile to destroy their own satellite in space just to say the could, and they succeeded, vastly increasing the dangerous debris cloud floating now in orbit. It was a military demonstration.
Proxima Centauri, is our nearest star, about 4 light years away.
A light year is the distance light travels in one year, or 9,460,730,472,581 kilometers. That’s 9.46 trillion kilometers, or about 5.88 trillion miles.
The fastest space ship we ever built was the Juno spacecraft, which in 2016 broke all speed records in space with a gravity assisted acceleration up to 164,700 mph.
The problem with going much faster than that is General Relativity and propulsion. Even with all the fuel in the solar system, it would still take an infinite amount of fuel to approach the speed of light. There’s no warp speed or aliens that have somehow “broken” the laws of physics. You can’t approach the speed of light.
If, however, you could go, say 40 times faster than Juno (there’s no existing technology that would come anywhere near this speed), you’d be going about 6.58 million miles an hour. That’s a hypothetical but impossible speed by either humans or space faring aliens, but none the less, for the sake of argument, let’s say you could go that fast.
Light travels at 670,616,629 miles per hour (as a layman and lazy American I think in miles more easily). So your space craft is amazingly, impossibly, traveling slightly less than 1% the speed of light. We’ll round it up for arguments sake. You’re going now 6.7 million miles an hour. Don’t crash into an asteroid at that speed!
How long would it take to make the trip to Proxima Centauri 4 light years away? Well, if you were going 1% the speed of light (6.7 million miles an hour) it would take you 400 years to reach the nearest star.
Unfortunately, you can’t just get up and go 6.7 million miles an hour. You’ve got to build up speed, which conceivably would take years burning some kind of fuel source that would weigh as much as the Moon because you’d need so much of it (which would slow your acceleration). The problem is the faster and longer you want to burn fuel, the more fuel you need, which increases your weight and decreases your acceleration. Remember, also, as you approach any percentage of the speed of light at all, the amount of fuel required to accelerate your spacecraft any faster begins to increase exponentially because of the law of General Relativity.
At the other end of the trip you’d need the same time and fuel to slow down so you don’t overshoot your target.
People have thought about using light propulsion. From somewhere in Earth orbit, shooting a powerful laser at a reflector at the back of the outgoing spaceship. It would be slow, but eventually it would increase in speed. They’d still need fuel at the other end to slow down.
It’s difficult to know how to figure in that acceleration and deceleration process, so I usually, for the sake of argument, just double the time, which probably isn’t far off.
That would mean it would take you about 880 years to start out, accelerate to 6.8 million miles per hour, and then slow down at the other end. That’s how long it would take to reach our nearest star.
As far as we know, there’s not even any interesting planets over there. If you want to go somewhere more interesting you’d probably have to go farther out in a different direction to the Trappist-1 system, which is 40 light years away.
That would only take you 8,000 years each way. We’re talking eight thousand years. You’d need a generational spacecraft, where hundreds of people lived and died for thousands of years before they reach where they’re going. Would these descendants of the original pioneers have any idea what to do when they got there? Would they resent being in space because their ancestors decided they should be? Would the spacecraft hold up and not fall apart after 8,000 years of usage? How would they have enough food and water?
Depressingly, these are only the closest stars, right around our neighborhood. There are many more stars in our local group, and billions more in the galaxy, and millions of galaxies.
All we can do is watch them, study them, wonder about them and so on. We will, however, never be able to visit them, and those aliens out there unable to visit us.
This rather large SpaceX rocket is called the Falcon Heavy. Inside is the automobile below, which SpaceX hopes to launch in orbit around Mars with a flight schedule February 6, 2018 (assuming it doesn’t blow up on the launchpad).
You just can’t make this stuff up. The automobile, which belongs to the founder of SpaceX Elon Musk, is a Tesla Roadster. If successful, the automobile could stay in orbit around Mars for a few billion years. The car will just be let go to float on it’s own ’round and ’round Mars.
I guess that’s in case you ever need to catch a ride to orbit Mars!
I know. It’s sad. Depressing really. Humans will never build a city off our planet Earth.
I say this because of distances. Even if we were to find a planetary candidate, it would take hundreds or thousands or more years to go one way to visit it just to see if the candidate is really like we need, what to speak of building a city.
Distances in space are unimaginably big. Let’s say the nearest star is 4 light years away. There is no guarantee there is life over there, but to travel that 4 light years will not take 4 years, or 40 years. At the fastest speed ever achieved it would take at least 150 years each way.
Suppose we wanted to take a closer look at the Trappist-1 system, 40 light years away. It is the next best candidate for life. That would take a mere 1,500 to 2,000 years to go one way just to see if anything really was habitable, what to speak of building a city.
Sadly, this is indeed science fiction. We want it to happen, so badly, but it never will happen. At most we might leave some foot prints on Mars and send some robotic systems to the moons of Jupiter and Saturn, but that’s it. Long before our sun blows up, life on Earth will be extinguished.
There certainly HAVE been fatalities in space. One took place right over my home when the shuttle Columbia burned up on re-entry, killing all aboard. Another happened when the shuttle Challenger blew up when it launched, killing all aboard. Where have you been?