On Nov 14, 9:59*am, Lord Valve wrote:
John Smith wrote:
On 11/13/2011 2:19 PM, Lord Valve wrote:
John Smith wrote:

On 11/13/2011 10:25 AM, Lord Valve wrote:
Don Pearce wrote:

On Sun, 13 Nov 2011 08:38:28 -0700, Lord Valve
* wrote:

dave wrote:

On Sun, 13 Nov 2011 11:39:03 +0000, Geoffrey S. Mendelson wrote:

It is much more important to know exactly how long and how well your
satellite is going to work than to hope to get longer by using a
technology that might last longer, but will more probably die
unexpectedly when struck by a cosmic ray burst.

Sometimes you can not predict how long a satellite will be used.. A
friend of mine worked on a civilian satellite for a defense contractor
and just before the division was sold off, cleaned out any old documents
and files they had on it.

Since the satellite he had worked on was way past its expected life (but
still in use), the contracts had long expired, the work was not
classified and a new improved one was due to be launched in a few days,
he was told to dump it all.

A few days later, the booster exploded on the pad, and the replacement
was destroyed.

The sattelite was kept running for many years, although there were no
documents on what to do or how it was built.

Geoff.

What good is a diagram if the unit is 24,000 miles in the air?

It had better *not* be in the air... *;-)

Besides - I saw mention upthread of using the ambient
vacuum with just the tube elements, rather than a typical
evacuated glass (or other material) enclosure...is the
vacuum in geosynchronous orbit really hard enough?
It would seem to me that there are probably plenty of
gas molecules floating around at that height, even if
it would still qualify as a "soft" vacuum. *Anybody?

Lord Valve

For all sorts of other reasons, standard enclosed tubes are used. Main
reasons are first to contain the electrons so other metalwork doesn't
get involved, and second to maintain the correct physical positioning.
The helix is of very fine tolerance in both pitch and positioning.
Space is certainly hard enough, but the environment around a satellite
is frequently not space, but a diffuse cloud of exhaust gas which
would extinguish a TWT immediately.

d

Ah. Good point!

Satellites do indeed need to use propellant of some sort
to keep in position; I didn't think of that at all. *And it
would seem that even if the ambient vacuum were
hard enough, conventional construction of the TWT
would be needed to keep contaminants out of it during
the satellite assembly process down on Terra firma.
But I must admit, the idea of using ambient vacuum
tickles my fancy a bit. *;-)

Lord Valve

I don't recall anyone ever claiming there was no enclose on the devices
... just the reasons for enclosing them the way we do on earth is now
gone ...

Regards,
JS

Do you actually read this ****, or have you been into the medicine cabinet?

Lord Valve
shrug

I usually don't read imbecilic stuff ... such as yours. *But, if I do, I
certainly do not take it seriously ... perhaps you will have better luck
with others.

Regards,
JS

Oh.

So, you're just another garden-variety ****. *shrug
Y'all have a Real Nice Day now, y'heah?

Got guns?

Lord Valve
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John Smith confessed once that he sleeps with a side arm under his
pillow!