Deap Space Navigation

In article v,
Bill Higgins wrote:
I wonder whether someone could build a deep-space tracking station in Chile
or Argentina and *sell* tracking services to the governments who need it? ...
This might be a dumb idea. Even if it looked potentially profitable, it
would be hard to finance without firm committments from government
customers.

The investment needed for deep-space stuff is pretty steep, I fear, and
most of the likely customers already have *some* facilities of their own
(e.g., ESA has just finished building itself a couple of sizable dishes),
so making a financial case for it could be hard.

There already is an outfit -- Universal Space Network Inc. -- that sells
dish time, but its dishes are smaller stuff (up to 15m) meant primarily
for Earth-orbit work.
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Henry Spencer wrote:
In article v,
Bill Higgins wrote:
I wonder whether someone could build a deep-space tracking station in Chile
or Argentina and *sell* tracking services to the governments who need it? ...
This might be a dumb idea. Even if it looked potentially profitable, it
would be hard to finance without firm committments from government
customers.

The investment needed for deep-space stuff is pretty steep, I fear, and
most of the likely customers already have *some* facilities of their own
(e.g., ESA has just finished building itself a couple of sizable dishes),
so making a financial case for it could be hard.

There already is an outfit -- Universal Space Network Inc. -- that sells
dish time, but its dishes are smaller stuff (up to 15m) meant primarily
for Earth-orbit work.

Well, who owns Arecebo? And is there another, possibly smaller, crater
that might be available for a similar installation? Yeah, you have a
sidelobe problem and some issues unless you can get it perfectly parabolic,
but in terms of dBi per dollar it seems the best approach on a budget.
--scott

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In article ,
Scott Dorsey wrote:
The investment needed for deep-space stuff is pretty steep, I fear...

Well, who owns Arecebo?

Some combination of Cornell (which runs it) and the US government (which
funds it). It's probably officially government property, with Cornell
just the operator.

And is there another, possibly smaller, crater
that might be available for a similar installation? Yeah, you have a
sidelobe problem and some issues unless you can get it perfectly parabolic,
but in terms of dBi per dollar it seems the best approach on a budget.

Valleys with vaguely suitable shapes, you can find. The big problem is
that an Arecibo-type dish is not very steerable. It can only look at
things in a limited range of celestial latitudes, and even if your target
is in that strip of sky, you only get one short look each day. For
communications, I doubt that the greater collecting area makes up for
this.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

"Scott Dorsey" wrote in message
...

Well, who owns Arecebo?

I believe NSF.

And is there another, possibly smaller, crater
that might be available for a similar installation? Yeah, you have a
sidelobe problem and some issues unless you can get it perfectly
parabolic,
but in terms of dBi per dollar it seems the best approach on a budget.

Except you get much more limited steering.


--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

A friend visited Greenbank national observatory recently. All but one
dish is mothballed stored pointing straight up. Seems no one wants to
buy user time on any but the largest dish there.

Maybe there is just too much radio noise to use small dishes.

Brian

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wrote in message
ps.com...
A friend visited Greenbank national observatory recently. All but one
dish is mothballed stored pointing straight up. Seems no one wants to
buy user time on any but the largest dish there.

"Brian Gaff" wrote in message
news
Maybe there is just too much radio noise to use small dishes.


Most likely not at Greenbank. It's in a valley where all other radios are
banned. In fact non-diesel engines are banned because the spark plugs
interfere with the radio receiving.


Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


wrote in message
ps.com...
A friend visited Greenbank national observatory recently. All but one
dish is mothballed stored pointing straight up. Seems no one wants to
buy user time on any but the largest dish there.

A friend visited Greenbank national observatory recently. All but one
dish is mothballed stored pointing straight up. Seems no one wants to
buy user time on any but the largest dish there.

Well, the Howard E. Tatel telescope, for example, is 26 meter.

That's pretty small by Deep Space Network standards. I couldn't give
numbers, but this isn't the only unused radio telescope in this size
range (I remember one in Colorado that people wanted to use for an
amateur Mars missions for example).

Bill Higgins writes:


I wonder whether someone could build a deep-space tracking station in Chile
or Argentina and *sell* tracking services to the governments who need it? I
don't suppose it would pay, unless one could achieve big savings in hardware
or infrastructure compared to government-operated stations.


NASA *had* a site in Chile. As it happens, I took a trip there for
wholly unrelated reasons with another engineer who decades before,
had worked for Huge Aircrash Corp. {as he called it} constructing
the station. He'd been in Santiago when Pinochet assassinated Allende.
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In sci.space.history message , Wed, 20 Dec
2006 23:41:51, Henry Spencer wrote:

Valleys with vaguely suitable shapes, you can find. The big problem is
that an Arecibo-type dish is not very steerable. It can only look at
things in a limited range of celestial latitudes, and even if your target
is in that strip of sky, you only get one short look each day. For
communications, I doubt that the greater collecting area makes up for
this.

Below, "aerial" means "'wiring' to/from radio waves converter" and does
not mean "above the ground".

AIUI, Arecibo has a shallowish upwards-facing dish and over it is
suspended an aerial cabin in a fixed (?) position.

How about (in another valley) having a near-hemispherical upwards-facing
dish with an aerial assembly on motorised cables so that it could
routinely be moved wherever required in the bowl, so steering the beam
over the entire upwards hemisphere? There would of course be a loss of
effective area away from the vertical; but ISTM that, while not too near
the horizon, the loss would not be great. The aerials would be dockable
at the centre of the dish, for access.

The dish could be actively shaped to be a paraboloid of appropriate axis
orientation, or some equivalent of a correcting lens could perhaps be
used.

Or the assembly on the cables could itself be a smaller mirror, shaped
to redirect the waves onto a hut-with-aerials at the centre of the bowl
(Tip : beware flash floods!).

Or phase-shifting might be employed between the aerial assembly and the
rest of the electronics.

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