Too True!!!
Go for it and get that record, then turn it around in 2 weeks and then
get the X-prize.
Anybody know of a net broadcast that I can (we) pick up the flight?
--
Sean
Level 1 RSO
www.pigmasterrockets.com
www.blackknights.org.uk
www.ukra.org.uk
Hello: could someone explain how Burts plane can go into low earth
orbit, without having to achieve the escape velocity of the earth? When
would the escape velocity take effect if he had wanted to go higher?
thank you
It didn't go into orbit, just went up to "space" altitude and back down.
He would have needed more velocity to reach low earth orbit. (Compare the
Redstone and Atlas flights, both launching similar Mercury capsules...)
-dave w
without having to achieve the escape velocity of the earth? When
Escape velocity is needed to move beyond Earth orbit; the Moon or Mars, for
example. Orbital velocity is needed to achieve Earth Orbit. Space Ship One
is not capable of either.
Clifton W. wrote:
<< Hello: could someone explain how Burts plane can go into low earth orbit,
without having to achieve the escape velocity of the earth? When would the
escape velocity take effect if he had wanted to go higher? >>
Hi Clifton! Spaceship One didn't go into orbit, it merely went high enough to
reach space. (Same with Alan Sheppard's first flight in Mercury.) To reach low
orbit, they would have needed to go much faster, somewhere around 17,000 mph if
I remember correctly. Escape velocity is even faster, and is the speed required
to leave Earth orbit.
Picture a porpoise or dolphin jumping out of water. Just enough speed to break
free for
an instant, but they fall back into their atmosphere (water). That's what space
ship one
accomplished. He made it to space, but was still being strongly influenced by
gravity and
it pulled him back down.
steve
Dumb question time... but how would 'escape velocity' even apply to
Spaceship One (which 'launched' from 50,000 ft)? I mean, I thought escape
velocity was the initial velocity (ignoring drag) needed when taking off
from the surface of the Earth, without any additional thrust after escape
velocity is achieved. On the other hand, you could escape Earth's gravity
as slowly as you like, as long as you can continue to apply just enough
thrust to more than counteract gravity. Right?
Mick wrote:
<< Dumb question time... but how would 'escape velocity' even apply to
Spaceship One (which 'launched' from 50,000 ft)? I mean, I thought escape
velocity was the initial velocity (ignoring drag) needed when taking off from
the surface of the Earth, without any additional thrust after escape velocity
is achieved.>>
"Escape velocity" is the speed needed to escape Earth orbit (somewhere around
25,000 mph, if I remember correctly). Where and how you launch is irrelevant.
Being dropped from a plane at 50,000 feet simply means that the rocket won't
have to work as hard or burn as much fuel as it would from a standing start on
the ground.
<<On the other hand, you could escape Earth's gravity as slowly as you like, as
long as you can continue to apply just enough thrust to more than counteract
gravity. Right? >>
Escape velocity is just a specific speed, like 65mph on the freeway. You can
reach that speed slowly, accellerating gradually. Or you can reach it quickly,
"pedal to the metal".
can
quickly,
But... Let's say I am gaining altitude at a constant rate of 1000 mph (far
less than the Earth's escape velocity), and continue to do so. Eventually,
I will escape the Earth, the solar system, and the galaxy, won't I? And if
not, how come?
Sure. You will have to have some constant thrust to oppose the
gravitational forces acting on you so as to maintain your constant
velocity (relative, I guess, to the point you are heading to), but you
would eventually get where you want to go.
You were right the first time. Escape velocity is the initial velocity
needed to escape the earths gravitational field (from the surface)
without any additional energy input.
http://www.physlink.com/Education/AskExperts/ae158.cfm
Mick wrote:
<< But... Let's say I am gaining altitude at a constant rate of 1000 mph (far
less than the Earth's escape velocity), and continue to do so. Eventually, I
will escape the Earth, the solar system, and the galaxy, won't I? >>
Yes. Of course, to maintain a constant rate like that would require continual
thrust, at least until you were far enough away in deep space.
If you simply accellerated to 1000mph, then turned off the engines, you would
slow down as Earth's gravity pulls on your ship, and eventually you'd fall back
to Earth. This is what happens with our sport rockets -- rapid accelleration to
a high speed, followed by loss of thrust, slowing and eventually return.
"escape velocity", 25,000 mph, is essentially the instantaneous velocity
necessary form sea level to leave Earths gravity. Think muzzle velocity from
a gun. Of course if you continue to travel at a slow but steady speed, you
will leave Earth behind. But this requires thrust the whole time. Up until
now, all of our launch vehicles have been high thrust for a short time, then
coast the rest of the time.
Any one remember the original Salvage One movie where the ex-astronaut uses
a Ferari to demonstrate how NASA went to the moon, then his concept for a
lunar flight.
Orbital velocity, for low earth orbit (shuttle, ISS, MIR, etc, NOT
geosynchronous satellites) is 17,000 mph. While a slow low thrust spacecraft
may get there, it won't be able to STAY in LEO unless it is travelling at
17000 mph.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD"
>>> To reply, remove the TRABoD! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf
www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
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