what is the next step after rockets?

[awlaskov]

i was wondering what is the fastest speed humans have reached in space travel to this day and what is the next leap in space travel i mean after space rockets working on combustion of a carburant that sure seem to have a speed limit how can we jump to much higher speeds to reach distant planet within our lifetime if someone has the answer please reply

thx

[CaptainPanic]

Already in use: ion thrusters

http://en.wikipedia.org/wiki/Ion_thruster

 

Not yet possible, but at least the physics seems to work: Project Orion

http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

 

Impossible so far:

A lot of sci-fi stuff

 

But we should realize: The next star is 4 light years away...

The link at the bottom of my post gives a map of the 50 lightyears around our sun. There are 133 stars mapped... and there are approximately 2000 stars in total within the 50 lightyears around ourselves. There may be many planets in this bubble...

In any case, the propulsion methods that I just listed will struggle to reach even the nearest stars within the lifetime of a person.

 

http://www.atlasoftheuniverse.com/50lys.html

same type of website as above: a map of the local neighborhood, but with zoom in, and zoom out:

http://www.atlasoftheuniverse.com/250lys.html

Edited October 27, 2010 by CaptainPanic

[lemur]

I think hydrogen-fusion technologies have to be developed and refined to facilitate any kind of sustainable interstellar travel. I believe hydrogen gas is readily available in many location, which will make refueling easier.

[Mr Skeptic]

Well there's also the nuclear powered rockets. Rather than burning propellant, they heat it up using a fission reactor. Such engines have been built and tested, and are more efficient than the best chemical rockets -- but also much heavier. The limit for these is not how hot the fuel burns like in chemical rockets, but how hot you can heat your fuel without melting your engine. A few designs like the nuclear lightbulb could make for very good rockets, although I don't think that design has been tested. But if it could be made it would be a good heavy lift vehicle that actually was recyclable.

 

As for getting off the earth cheaply, I think the best would be a launch loop, which could toss stuff into space very cheaply and in bulk, and powered by a terrestrial power source (coal, nuclear, solar, whatever floats your boat). It's not a rocket though, so the things it lobs into space would have to have their own propulsion if they want to go anywhere other than their trajectory.

 

As for getting to another star, I think the most realistic is Project Longshot, though I guess 100 years for reaching the nearest star is still a bit longer than you might want to spend on a spaceship.

[Moontanman]

How about The Mach-Effect (ME) drive http://www.centauri-dreams.org/?p=1324, does anyone know if this is legitimate?

[lemur]

As for getting off the earth cheaply, I think the best would be a launch loop, which could toss stuff into space very cheaply and in bulk, and powered by a terrestrial power source (coal, nuclear, solar, whatever floats your boat). It's not a rocket though, so the things it lobs into space would have to have their own propulsion if they want to go anywhere other than their trajectory.

This topic really deserves its own thread. It's a favorite of mine when it comes to space-technology discussions. I once thought that the tall volcano on Mars next to a very deep sea could have been used as a long launch-track by ancient Martians. If you would lob things into space, it would make sense to do so above a large volcano to take advantage of the hot, light, upward-moving air currents rising off the volcano, no?

[Ophiolite]

If you would lob things into space, it would make sense to do so above a large volcano to take advantage of the hot, light, upward-moving air currents rising off the volcano, no?

No. Simply contemplate the order of magnitude differences between the velocity of the lobbed item when it left the track at the top of the volcano and the velocity of the air currents. Any benefit would be completely undetectable.

 

The advantage of using Olympus Mons would be three fold, none of which relate to air currents:

1) Closer to the equator, so gain rotational velocity.

2) Further from the centre of the planet, so gravity is weaker.

3) Above the majority of the atmospher so air resistance is lower.

[lemur]

No. Simply contemplate the order of magnitude differences between the velocity of the lobbed item when it left the track at the top of the volcano and the velocity of the air currents. Any benefit would be completely undetectable.

 

The advantage of using Olympus Mons would be three fold, none of which relate to air currents:

1) Closer to the equator, so gain rotational velocity.

2) Further from the centre of the planet, so gravity is weaker.

3) Above the majority of the atmospher so air resistance is lower.

 

Any idea what the "lob" velocity would have to be to achieve orbit then? I suppose you could lob a vehicle to a certain height where it could subsequently use propulsion to continue further. Maybe it would be possible to have a catch-net suspended from something in low geo-synchronous orbit. Is any of this reasonably plausible at all?

[Ophiolite]

Any idea what the "lob" velocity would have to be to achieve orbit then? I suppose you could lob a vehicle to a certain height where it could subsequently use propulsion to continue further. Maybe it would be possible to have a catch-net suspended from something in low geo-synchronous orbit. Is any of this reasonably plausible at all?

You need to define your conditions more precisely. In particular.

1. Are we still talking about Mars in general and Olympus Mons in particular?

2. When are we talking about it? i.e. what will the atmpospheric density be? MArs used to have a dense atmosphere.

 

The trouble with Mars is the atmosphere would extend to a greater height than on Earth, so that even at the summit of Olympus Mons there would be significant air resistance. The velocity you would have to achieve to overcome this and gain orbit might simply be impractical because of the amount of heat generated by friction. Far better to get up a good velocity, get beyond most of the atmosphere, then kick in with the rest of your propulsive power, presumably rocket.

[lemur]

You need to define your conditions more precisely. In particular.

1. Are we still talking about Mars in general and Olympus Mons in particular?

2. When are we talking about it? i.e. what will the atmpospheric density be? MArs used to have a dense atmosphere.

I don't know, either way. I was just wondering if you might have a general idea about what kind of speed would need to be achieved to lob a vehicle into orbit, or at least high into the air. I was hoping for a discussion of the forces and energy involved with that.

 

The trouble with Mars is the atmosphere would extend to a greater height than on Earth, so that even at the summit of Olympus Mons there would be significant air resistance. The velocity you would have to achieve to overcome this and gain orbit might simply be impractical because of the amount of heat generated by friction. Far better to get up a good velocity, get beyond most of the atmosphere, then kick in with the rest of your propulsive power, presumably rocket.

Maybe the best vehicle design for lobbing vehicles as high as possible before initiating propulsion would be flying saucers. This design has become cliche' due to bad sci-fi but a rotating saucer does have a gyroscopic effect to keep it flat and it is steamlined; but of course most importantly it can be lobbed unlike a radially asymmetrical cylinder-type vehicle. Isn't discus the olympic projectile that has the greatest ratio of distance to weight?

 

 

 

[Ophiolite]

I don't know, either way. I was just wondering if you might have a general idea about what kind of speed would need to be achieved to lob a vehicle into orbit, or at least high into the air. I was hoping for a discussion of the forces and energy involved with that.

For approximate values it is fairly simple physics, but its almost not simple enough for me. I'll take a look at it in day or two when I have time.

 

Maybe the best vehicle design for lobbing vehicles as high as possible before initiating propulsion would be flying saucers. This design has become cliche' due to bad sci-fi but a rotating saucer does have a gyroscopic effect to keep it flat and it is steamlined; but of course most importantly it can be lobbed unlike a radially asymmetrical cylinder-type vehicle. Isn't discus the olympic projectile that has the greatest ratio of distance to weight?

This is just intrinsically wrong, but it will take too long to repsond just now. Again, I'll try to come back later to address your points.

[swansont]

!

Moderator Note

"gravitational Isolator" tangent has been moved" http://www.scienceforums.net/topic/44715-the-gravitational-isolator/

[Skaffen]

Evolution suggests that we will follow the example of all other 'lower level' life forms when it comes to growing beyond our current limitations. Just as a virus infects it's host cell to reconfigure it into a method of propagation, humankind must do the same. We will not as a species leave this planet - No need it is already travelling through space and besides where would we go without redefining our environment and ultimately ourselves? We as a species will manipulate our cell (Earth) until it is fit for purpose, following that we may decide to travel towards the Galactic centre to meet up with other advanced species (i.e. travel to the centre of the Galactic cell). Seems fantastical but then again we have emerging nanotechnology and fusion around the corner....early days.

 

Universal 'truths' apply on all scales, with regards to evolution the pattern has been established and is quite evident - the human ego as a powerful source to develop many pov's/theories is also restricting our ability to work holistically. Plant cells do it, stomach bacteria do it, even the ants do it....work together for a greater construct as a colony and the results are staggering....Egyptians done it for a bit and we still consider it almost mystical, amazing what we've lost in the past 3500 years.