In 1966, the Soviet Luna 9 survived a near-vertical landing on the Moon with a speed of about 50km/h (approx 30mph). It used an inflated bag to cushion the impact.
In 1997, America's Pathfinder rover used a similar technique and touched down on Mars with a similar vertical speed. It was designed to take an impact about fifty percent greater than it actually experienced.
It would be possible to land something at a high velocity, providing the vertical component is not much more than that of Luna 9 or Pathfinder. Horizontal speed can be killed by rolling and bouncing, as happened with Pathfinder when it struck the surface at an angle of about 50 degrees.
The downside of this approach comes in the form of any significant vertical obstruction such as a large boulder or a cliff face.
Bob Christy
============================================================== What speed do you think would be max survivable speed for a landing on the moon for a robot, or comm system?
How fast could something hit and survive?
Joe
That's exactly as I was thinking.
With no atmosphere, the moon, you could in theory orbit with a decaying orbit until it was only as high as the surface, (But of course the mountains are a problem.)
But Some numbers were crunched,, and say a lander was orbiting, and slowed down just the right amount that it began to decay. ever soo slowly, in theory of it was a perfect sphere and smooth as glass the thing could orbit inches above the surface true?
But the moons gravity is very un even as well as the surface.. But give the sphere and smooth thought,
It could orbit and eventually land at a speed of, 1.68 km per second or slightly over 6000 MPh! don't think it could survive.
Oh well..
Bob Christy wrote:
In 1966, the Soviet Luna 9 survived a near-vertical landing on the Moon with a speed of about 50km/h (approx 30mph). It used an inflated bag to cushion the impact.
In 1997, America's Pathfinder rover used a similar technique and touched down on Mars with a similar vertical speed. It was designed to take an impact about fifty percent greater than it actually experienced.
It would be possible to land something at a high velocity, providing the vertical component is not much more than that of Luna 9 or Pathfinder. Horizontal speed can be killed by rolling and bouncing, as happened with Pathfinder when it struck the surface at an angle of about 50 degrees.
The downside of this approach comes in the form of any significant vertical obstruction such as a large boulder or a cliff face.
Bob Christy
============================================================== What speed do you think would be max survivable speed for a landing on the moon for a robot, or comm system?
How fast could something hit and survive?
Joe _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
What would cause it to "decay" with no atmosphere?
-- Nate Duehr Sent from my iPhone
On Feb 15, 2009, at 7:51, Joe [email protected] wrote:
That's exactly as I was thinking.
With no atmosphere, the moon, you could in theory orbit with a decaying orbit until it was only as high as the surface, (But of course the mountains are a problem.)
But Some numbers were crunched,, and say a lander was orbiting, and slowed down just the right amount that it began to decay. ever soo slowly, in theory of it was a perfect sphere and smooth as glass the thing could orbit inches above the surface true?
But the moons gravity is very un even as well as the surface.. But give the sphere and smooth thought,
It could orbit and eventually land at a speed of, 1.68 km per second or slightly over 6000 MPh! don't think it could survive.
Oh well..
Bob Christy wrote:
In 1966, the Soviet Luna 9 survived a near-vertical landing on the Moon with a speed of about 50km/h (approx 30mph). It used an inflated bag to cushion the impact.
In 1997, America's Pathfinder rover used a similar technique and touched down on Mars with a similar vertical speed. It was designed to take an impact about fifty percent greater than it actually experienced.
It would be possible to land something at a high velocity, providing the vertical component is not much more than that of Luna 9 or Pathfinder. Horizontal speed can be killed by rolling and bouncing, as happened with Pathfinder when it struck the surface at an angle of about 50 degrees.
The downside of this approach comes in the form of any significant vertical obstruction such as a large boulder or a cliff face.
Bob Christy
============================================================== What speed do you think would be max survivable speed for a landing on the moon for a robot, or comm system?
How fast could something hit and survive?
Joe _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
There is atmosphere. Just not very much. There's also solar wind and bombardment by photons, which have mass and therefore exert a force on anything they hit.
Nate Duehr wrote:
What would cause it to "decay" with no atmosphere?
participants (4)
-
Bob Christy -
Joe -
Nate Duehr -
Nigel Gunn G8IFF/W8IFF