Shuttle liftoff

[C0RR0SIVE]

Im pretty sure the trailblazers of the space tourism industry will be strictly sub-orbital in the beginning, and probably for some time afterwards.

Like I said in my previous post, they won't really be into space just yet, they will be right on the edge so that a normal air craft can safely return to earth. Last I heard they will use two planes, one will be a normal jumbo jet with another jet on the top, the top one will launch when the jumbo jet hits its maximum altitude so that it will have enough fuel and power to reach space for a few minutes then come back to earth safely.

 

[molsen]

personally, if i had the money to pay for one of these commercial "space" flights, i would want to make a freaking orbit.... just going really high isn't worth the money, IMO

 

[PP Mguire]

Orbit and subspace is like the same thing. Only difference is your in the very most topmost layer of the atmosphere. 0 Gs is what most ppl wanna experience.

 

[thebleakness]

Orbit and subspace is like the same thing. Only difference is your in the very most topmost layer of the atmosphere. 0 Gs is what most ppl wanna experience.

I dont think so, orbit is where you are able to travel without the need of thrusters or w/e to keep from re-entering. Where these planes are going, they are so low that they are re-entering seconds after they reach the 0 g point.

And those are going to be much cheaper than flying into space on a shuttle to experience 0g in orbit. How much did that american rich guy pay the russians to take him too space? it was alot...

 

[molsen]

Orbit and subspace is like the same thing. Only difference is your in the very most topmost layer of the atmosphere. 0 Gs is what most ppl wanna experience.

no, not at all. if you're not in space, you can't be orbiting. an orbit is a constant state of freefall, but with a horizontal motion of 17,600mph or so (depending on your altitude) that requires no thrust to maintain. you won't experience zero g's unless you are in this freefall.

 

[magouster]

Can anyone explain the theory behind "escape velocity" to me? I think it's something like 28000MPH, not sure though. I don't get it! If you can keep a constant speed of 10MPH, surely, at some point, you'll leave the atmosphere.

 

[molsen]

escape velocity varies with altitude/distance from earth. it's the speed needed to escape the gravitational force of a body without propulsion (and has little, if anything, to do with getting into orbit). for example, if you threw a baseball straight up at a speed of 11.2 km/s from the ground, it would escape earth's gravitational pull (theroetically of course, not accounting for air resistance, which would make this feat impossible). however, at 9000km altitude, the speed needed for the baseball to escape is 7.1 km/s

numbers taken from http://en.wikipedia.org/wiki/Escape_velocity

escape velocity is not about constant speed with propulsion. sure, with constant propulsion, at 10 km/h you could go and go and go. you could do the same at a .0001 km/h. it's about the momentum of the object against the gravitational pull of another object.

another explanation: http://www.physlink.com/education/askexperts/ae158.cfm

"If you throw an object straight up, it will rise until the the negative acceleration of gravity stops it, then returns it to Earth. Gravity's force diminishes as distance from the center of the Earth increases, however. So if you can throw the object with enough initial upward velocity so that gravity's decreasing force can never quite slow it to a complete stop, its decreasing velocity can always be just high enough to overcome gravity's pull. The initial velocity needed to achieve that condition is called escape velocity."

so, ignoring air friction, escape velocity is around 25,000 mph (you were close!). however, astronauts travelling to the Moon or Mars would be concerned with the escape velocity from above the atmosphere, as no craft is going to go 25,000 mph within it. (the space shuttle re-enters the atmosphere at 15,000 mph and glows red hot!)