Dr. Goddard's Moon Rocket

Will tell us if radio waves can travel through space:
http://blog.modernmechanix.com/2008/...io-earthbound/

Pat

Pat Flannery wrote:
Will tell us if radio waves can travel through space:
http://blog.modernmechanix.com/2008/...io-earthbound/


Did people not already know that EM waves don't need a material medium?

Neil Gerace wrote:
Pat Flannery wrote:
Will tell us if radio waves can travel through space:
http://blog.modernmechanix.com/2008/...io-earthbound/


Did people not already know that EM waves don't need a material medium?

I'm still wondering if the rocket shown was a Goddard design, and he
thought something with a single stage could go all the way to the Moon.
I'm trying to remember how much was known about radio waves at the time
- had anyone noticed radio interference from the Sun by that time? If
so, that settled the radio through space question right there.

Pat

Pat Flannery writes:

Neil Gerace wrote:
Pat Flannery wrote:
Will tell us if radio waves can travel through space:
http://blog.modernmechanix.com/2008/...io-earthbound/


Did people not already know that EM waves don't need a material medium?

I'm still wondering if the rocket shown was a Goddard design, and he
thought something with a single stage could go all the way to the Moon.
I'm trying to remember how much was known about radio waves at the time
- had anyone noticed radio interference from the Sun by that time? If
so, that settled the radio through space question right there.

If I'm not mistaken, 1925 seems rather close to about when the
existence of the Heaviside layer --- the E region of the ionosphere ---
was first proven. Among other things this layer is a sort of mirror to
radio communications, allowing for the famous propagation of AM radio.

Based on the talk about Heaviside's Radio Wave Theory, and the
talk about how radio waves may be ``earthbound, being guided by the
electrical properties of the surrounding gases'' it sounds to me like
they were thinking any radio wave sent from Earth would be reflected
back by the layer, apparently unaware that it has to be the right
frequency and the right reflecting angle. (Well, everything's easy
after you know the answers.)

That we can observe earthshine on a nearly new moon shows that
light and therefore some radio waves from the surface of the earth
escape the Heaviside layer, although I suppose until the ionisphere was
better modelled it wouldn't be obvious the wavelengths useful for radio
communication would pass through.


I always find it remarkable how early rocket plans took it for
granted the first objective would be to fly to the Moon, with the ideas
of orbital or suborbital flight somehow inadequate enough when the goal
was testing whether one could communicate through the ionosphere.

--
Joseph Nebus
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Neil Gerace wrote:

Did people not already know that EM waves don't need a material medium?

Something I didn't think of (but should have, based on other replies to the above message) was that they might have been
in the dark as to which frequencies could get through the atmosphere and which would be absorbed or reflected by it.