Human shuttles and speed (of light)

[urbanleg]

Hi.

 

one of the main goals nowdays is accelerating space shuttles in speed so we could travel even while exploring the vast milky way galaxy

 

one thing is not clear to me, and thats why do we have to be limited with the shuttles speed at all? let me explain:

 

since there is no friction in space, and since our shuttles have their own engines to accelerate - how come , speed isnt accumulating to greater values?

take a normal shuttle that is packed with alot of fuel turn the engines on, lift off, after a while it leaves the earth atmosphire, and from this phase every ounce of fuel burnt accelerates the frictionless shuttle more and more as she gains speed.. with sufficient amount of fuel we could reach light speed and more dont we?

 

so how come there is a speed barrier (and which is not the speed of light)?

 

N.a

[insane_alien]

as you accelerate it take more and more energy to get that exta m/s of speed. this is asymptotic to the speed of light. this means it takes infinite energy to reach the speed of light.

 

as we have limited fuel(even if you turned the entire universe into fuel) we cannot reach the speed of light.

 

also, if you sent the space shuttle at anywhere near the speed of light it would disintigrate quite quickly from impacts with dust and other particles in space. at those sort of velocities a microgram particle of dust can deliver the destructive force of a hiroshima bomb quite easily.

[urbanleg]

thanks for the informed quick answer

[D H]

Hi.

 

one of the main goals nowdays is accelerating space shuttles in speed so we could travel even while exploring the vast milky way galaxy

No, it's not. While NASA does spend some (not very much) money on advanced propulsion technologies, none of those are targeted for use on the space station.

 

one thing is not clear to me, and thats why do we have to be limited with the shuttles speed at all? let me explain:

 

since there is no friction in space, and since our shuttles have their own engines to accelerate - how come , speed isnt accumulating to greater values?

Short answer: They have to bring the fuel with them. Longer answer: The ideal rocket equation; read the linked article.

 

If the fuel could be plucked out of space that would be a different story. Two ideas that do just that are Bussard ramjets and solar sails. (Google these terms.)

[insane_alien]

...none of those are targeted for use on the space station.

 

not true, they are planning to attach a VASMIR thruster to the station to do orbital boosts.

 

http://www.nasa.gov/vision/space/travelinginspace/future_propulsion.html

[Mokele]

Another point, much more important - consider how much acceleration, expressed in "g's", it would take to reach light speed in even a human lifetime.

 

The number you'll get will be enough to reduce any astronaut to a fine red paste.

 

Hell, any acceleration much above 1g will prove to be *very* problematic for long-term exposure.

[J.C.MacSwell]

Another point, much more important - consider how much acceleration, expressed in "g's", it would take to reach light speed in even a human lifetime.

 

The number you'll get will be enough to reduce any astronaut to a fine red paste.

 

Hell, any acceleration much above 1g will prove to be *very* problematic for long-term exposure.

 

Not sure how well a fine red paste would hold up at infinite "g's" either.

[D H]

not true, they are planning to attach a VASMIR thruster to the station to do orbital boosts.

Read the article again.

After VASIMR completes some additional earthbound testing, its designers

hope

for it to be tested in orbit onboard the International Space Station.

That article is a bit dated, written on May 15, 2003. Chang-Diaz' company has advanced to the point where those hopes to test the engine have come closer to reality. NASA and Ad Astra signed a Space Act Agreement for a flight test aboard the ISS.

The agreement is structured in a series of “gates,” designed to allow the parties to assess the requirements on an incremental basis while proceeding to flight. Upon the successful achievement of the milestones set forth in the agreement, NASA and Ad Astra envision that VASIMR™ will be launched to the ISS where the rocket can be tested, for the first time, in its intended environment: the vacuum of outer space.

 

The only plans NASA has now is to allow Ad Astra Rocket to test their engine. NASA obviously sees promise in the engine, but as far as "planning to attach a VASMIR thruster to the station to do orbital boosts"? Not yet. Not even close.