Jump to content




Welcome to Unexplained Mysteries! Please sign in or create an account to start posting and to access a host of extra features.


- - - - -

Why can't we use a linear accelerator....


  • Please log in to reply
19 replies to this topic

#1    XenoFish

XenoFish

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,331 posts
  • Joined:27 Jul 2013
  • Gender:Male
  • Location:Between here and there

  • Freedom is an illusion

Posted 26 August 2014 - 12:14 AM

Okay, this is a stupid question. But could we use a linear accelerator (rail gun) to launch shuttle missions into deep space at hyper velocity speeds? This would greatly reduced the travel time in my thinking. Educate me people.

Sometimes to kill an idea, you must change it.

#2    The Id3al Experience

The Id3al Experience

    Paranormal Investigator

  • Member
  • PipPipPipPipPipPip
  • 854 posts
  • Joined:20 Sep 2010
  • Gender:Male
  • Location:New Zealand

  • "Live with cause and leave results to the great law of the universe, passing each day in peaceful contemplation"

Posted 26 August 2014 - 12:33 AM

I guess for now, you simply can not get enough thrust to lift it into high Earth orbit. However they are working on it.

Posted Image

#3    XenoFish

XenoFish

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,331 posts
  • Joined:27 Jul 2013
  • Gender:Male
  • Location:Between here and there

  • Freedom is an illusion

Posted 26 August 2014 - 12:42 AM

I figured a launch system could be built in space similar to the space station, piece by piece. Using solar panels to accumulate the energy required.

Sometimes to kill an idea, you must change it.

#4    Ugly1

Ugly1

    Remote Viewer

  • Member
  • PipPipPipPip
  • 568 posts
  • Joined:07 Jun 2007
  • Gender:Not Selected
  • Location:Texas USA

Posted 26 August 2014 - 12:56 AM

Are you referring to manned or an unmanned mission? With a manned mission you would be looking at incredible G-forces that would scramble a persons brain unless you had a way to zero out the gravity around the spaceship.


#5    danielost

danielost

    Forum Divinity

  • Member
  • 31,308 posts
  • Joined:26 Nov 2007
  • Gender:Male
  • Location:the only known inhabited planet in the universe

Posted 26 August 2014 - 12:59 AM

View PostXenoFish, on 26 August 2014 - 12:14 AM, said:

Okay, this is a stupid question. But could we use a linear accelerator (rail gun) to launch shuttle missions into deep space at hyper velocity speeds? This would greatly reduced the travel time in my thinking. Educate me people.

Simple, the human body couldn't with stand the g forces.  But for unmanned mission we could.

I am a Mormon.  If I don't use Mormons believe, those my beliefs only.
I do not go to church haven't for thirty years.
There are other Mormons on this site. So if I have misspoken about the beliefs. I welcome their input.
I am not perfect and never will be. I do strive to be true to myself. I do my best to stay true to the Mormon faith. Thanks for caring and if you don't peace be with you.

#6    danielost

danielost

    Forum Divinity

  • Member
  • 31,308 posts
  • Joined:26 Nov 2007
  • Gender:Male
  • Location:the only known inhabited planet in the universe

Posted 26 August 2014 - 01:02 AM

View PostUgly1, on 26 August 2014 - 12:56 AM, said:

Are you referring to manned or an unmanned mission? With a manned mission you would be looking at incredible G-forces that would scramble a persons brain unless you had a way to zero out the gravity around the spaceship.

It isn't gravity but acceleration that produces the g force.  Of course being in gravity well doesn't help.

I am a Mormon.  If I don't use Mormons believe, those my beliefs only.
I do not go to church haven't for thirty years.
There are other Mormons on this site. So if I have misspoken about the beliefs. I welcome their input.
I am not perfect and never will be. I do strive to be true to myself. I do my best to stay true to the Mormon faith. Thanks for caring and if you don't peace be with you.

#7    The Id3al Experience

The Id3al Experience

    Paranormal Investigator

  • Member
  • PipPipPipPipPipPip
  • 854 posts
  • Joined:20 Sep 2010
  • Gender:Male
  • Location:New Zealand

  • "Live with cause and leave results to the great law of the universe, passing each day in peaceful contemplation"

Posted 26 August 2014 - 01:13 AM

View Postdanielost, on 26 August 2014 - 01:02 AM, said:

It isn't gravity but acceleration that produces the g force.  Of course being in gravity well doesn't help.

I would of thought it was both acting to produce it, without gravity, you have no acting force to have a g force.

Edited by The Id3al Experience, 26 August 2014 - 01:15 AM.

Posted Image

#8    XenoFish

XenoFish

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,331 posts
  • Joined:27 Jul 2013
  • Gender:Male
  • Location:Between here and there

  • Freedom is an illusion

Posted 26 August 2014 - 06:29 AM

Mostly for manned mission. I was think more along the lines of a maglev train like setup. With a steady speed build up and in earth orbit. Not ground based.

Sometimes to kill an idea, you must change it.

#9    toast

toast

    President of the Galaxy

  • Member
  • 3,571 posts
  • Joined:24 Nov 2013
  • Gender:Male
  • Location:Germany

  • WARNING!REALITY ADVISORY!
    Posts by this user may contain
    statements that may offend
    publishers of pics/clips of
    supposed UFO/alien sightings.

Posted 26 August 2014 - 08:44 AM

View PostXenoFish, on 26 August 2014 - 12:14 AM, said:

Okay, this is a stupid question. But could we use a linear accelerator (rail gun) to launch shuttle missions into deep
space at hyper velocity speeds? This would greatly reduced the travel time in my thinking. Educate me people.
No, this is not a stupid question.
Besides the g-forces friction is the problem. To get into orbit the escape velocity of 11,2km/sec (40.320km/h
or Mach 32) must be reached by the vehicle during the ascent. As this hypothetical vehicle is not self propelled,
it must have a speed at the time it leaves the (vacummised) acceleration chamber, high enough that the speed
will not fall below 11,2km/sec due to atmospheric air drag during the ascent. I dont know the math how to
calcutate the needed initial speed but I would say it must be at least the double of 11,2km/sec, so 22,4km/sec
= Mach 64, to reach the orbit. But even if we take the 11,2km/sec value, any object that will be taken into the atmosphere at sea level with that speed will be vaporized/destroyed by atmospheric effects  immediately. Just
to compare, the Space Shuttles heat shields got heated up to 1300C at an altitude of approx 80km, where the atmospheric density is <1% than on sea level, at a speed of approx Mach 23.

Edited by toast, 26 August 2014 - 08:52 AM.

“For every moment of triumph, for every instance of beauty, many souls must be trampled.”  - Hunter S. Thompson -
"Very funny, Scotty, now beam down my trousers!" - James T. Kirk -
"I think enormous harm is done by religion – not just in the name of religion, but actually by religion." - Steven Weinberg -  
"I am discounting the reports of UFOs. Why would they appear only to cranks and weirdos?" - Stephen Hawking -

#10    sepulchrave

sepulchrave

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,799 posts
  • Joined:19 Apr 2009
  • Gender:Not Selected

Posted 26 August 2014 - 09:41 AM

View PostXenoFish, on 26 August 2014 - 12:14 AM, said:

Okay, this is a stupid question. But could we use a linear accelerator (rail gun) to launch shuttle missions into deep space at hyper velocity speeds? This would greatly reduced the travel time in my thinking. Educate me people.

If I understand correctly, you are talking about a space based platform for launching manned ships on deep space journeys.

This is a good idea. As long as the linear accelerator is long enough, you can reach hypervelocity speeds while keeping the ship at a comfortable 1g acceleration. In space it should not be that difficult to build a very long accelerator.

The only issue is slowing down once the ship has reached the destination.

If the destination is a common one, then it would be possible to build a linear accelerator there as well and with precise targeting you could launch the ship from the accelerator at our end into the accelerator at their end - then the destination accelerator could operate in reverse and slow the ship down.

Right now it is a difficult challenge because the best option for these accelerators are rail guns but constructing material to overcome the inherent friction in these is a problem

Fortunately (or unfortunately) various militaries are working on solutions to these problems for land-based weaponry, we can only hope that eventually these technologies will prove useful in more peaceful pursuits.

As others have mentioned, land-based rail guns are a good way of getting cargo into orbit (but again, slightly outside of our technological capabilities at the moment).

Typically these non-military rail guns are called mass drivers.


#11    Peter B

Peter B

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,446 posts
  • Joined:29 Mar 2009
  • Gender:Not Selected
  • Location:Yes We Can-berra!

Posted 26 August 2014 - 10:05 AM

One thought that occurs to me is Newton's law about equal and opposite acceleration: If you have the launching device in Earth orbit, it's in free fall. So when it launches something, it will be pushed back with the same energy it gives to the spacecraft. Now given that the launcher will have a lot more mass than the spacecraft, then the relative acceleration of the launcher will be a lot less than the acceleration of the spacecraft. But if nothing else it means that the direction the launcher is facing will matter, otherwise the launch process might push the launcher into the Earth's atmosphere (depending, of course, on how high up the launcher's orbit is). And the higher the launcher's orbit, the more energy it'll take to get the parts of the launcher and any spacecraft it launches up there.

I suppose one way to deal with that is to launch two spacecraft in opposite directions at the same time, and the accelerations will cancel out. But that requires you to want to launch spacecraft in exactly opposite directions - how often is that going to happen?


#12    Waspie_Dwarf

Waspie_Dwarf

    Space Cadet

  • 32,340 posts
  • Joined:03 Mar 2006
  • Gender:Male
  • Location:Bexleyheath, Kent, UK

  • We are all in the gutter, but some of us are looking at the stars.

    Oscar Wilde

Posted 26 August 2014 - 11:43 AM

The main reason that would hold back such an idea for the foreseeable future is economics.

Building such a large an complex structure in space would be hugely expensive. With only a few launches made into deep space each year it would remain cheaper to use rockets.

However if we were to colonise Mars then the regular flow of transport back and forth could conceivably make an orbital mass driver economically viable.

Many sci-fi authors have proposed mass drivers. A favourite use is on the moon. With no atmosphere there is not the friction problems that toast mentioned. A lunar mass driver could be a useful way of getting material mined on the moon into lunar orbit. Given the cost of hauling material into Earth orbit, lunar mining in conjunction with a mass driver could make it economically viable to construct future large spacecraft and space stations in lunar orbit.

"Space is big. Really big. You just won't believe how vastly, hugely, mind-boggingly big it is. I mean, you may think it's a long way down the street to the chemist, but that's just peanuts to space." - The Hitch-Hikers Guide to the Galaxy - Douglas Adams 1952 - 2001

Posted Image
Click on button

#13    Waspie_Dwarf

Waspie_Dwarf

    Space Cadet

  • 32,340 posts
  • Joined:03 Mar 2006
  • Gender:Male
  • Location:Bexleyheath, Kent, UK

  • We are all in the gutter, but some of us are looking at the stars.

    Oscar Wilde

Posted 26 August 2014 - 11:47 AM

View PostPeter B, on 26 August 2014 - 10:05 AM, said:

But if nothing else it means that the direction the launcher is facing will matter, otherwise the launch process might push the launcher into the Earth's atmosphere

The key here is this:

View PostPeter B, on 26 August 2014 - 10:05 AM, said:

the launcher will have a lot more mass than the spacecraft, then the relative acceleration of the launcher will be a lot less than the acceleration of the spacecraft.

The launcher will have a far smaller velocity imparted on it than the launched vehicle. It would not be difficult to compensate with thrusters. If the launcher is in low-Earth orbit it will need regular boosts anyway.

"Space is big. Really big. You just won't believe how vastly, hugely, mind-boggingly big it is. I mean, you may think it's a long way down the street to the chemist, but that's just peanuts to space." - The Hitch-Hikers Guide to the Galaxy - Douglas Adams 1952 - 2001

Posted Image
Click on button

#14    XenoFish

XenoFish

    Psychic Spy

  • Member
  • PipPipPipPipPipPipPipPip
  • 1,331 posts
  • Joined:27 Jul 2013
  • Gender:Male
  • Location:Between here and there

  • Freedom is an illusion

Posted 26 August 2014 - 04:34 PM

Quote

The only issue is slowing down once the ship has reached the destination.
I was thinking of counter thrusters. To decelerate the shuttle.

Sometimes to kill an idea, you must change it.

#15    WGH

WGH

    Apparition

  • Member
  • PipPip
  • 364 posts
  • Joined:07 Apr 2008
  • Gender:Male
  • Location:Warrington UK

  • Today is tomorrows yesterday, and yesterdays tomorrow.

Posted 28 August 2014 - 04:49 PM

View PostXenoFish, on 26 August 2014 - 04:34 PM, said:

I was thinking of counter thrusters. To decelerate the shuttle.

Wouldn't the energy and therefore fuel required be the same as it would to reach these speeds using thrusters anyway?





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users