- Cassini-Huygens Mission status report

Henry Spencer wrote:
But the big requirement is not more sites, but more antennas. There's no
reason to spread the antennas out over a dozen sites, which will just run
up operations costs. What you want to do is not to commission a bunch
more sites, but to commission a bunch more big dishes at the same three or
four sites.

As ESA is slowly but surely building up it's own deep space network, it
may take off some load on the DSN on joint missions and can support NASA
missions if necessary. Though the ESA's DSN is small compared with
NASA's, it's better than nuthin'.

Now, doing my assigned reading, I ran into the following, perhaps a typo,
perhaps a good story in here, perhaps I misunderstand it, perhaps my
ignorance. Dunno.

The Apollo mission will be supported by earth-based
forces in the prime recovery areas and by the three planned
deep space instrumentation facilities (DSIF) tracking sta-
tions in Spain, Australia, and Texas.

And Texas?

Source: SP-257: Apollo - A Program Review
National Aeronautics and Space Meeting
Los Angeles, 1964

"The Manned Lunar Landing Mission"
William A. Lee, Manned Spacecraft Center, NASA

--
rk



Henry Spencer wrote:

In article ,
Scott Hedrick wrote:
The DSN issue definitely is a bad one, though.

Somebody tell me why adding stations to the DSN isn't a top priority?

Basically, because it's hard to get serious money for infrastructure
upgrades like that. It doesn't help that (I'm told) DSN's management is
bureaucratic and timid, and is reluctant to face the need for major
growth. They are making improvements, but relatively modest ones that
aren't going to keep up with demand.

think that Japan, Diego Garcia, South Africa, Britain, Nova Scotia, Brazil,
Kansas, Easter Island and others should be good candidates.

There is no dire need for lots more sites, especially in places like Diego
Garcia and Easter Island where overhead costs would be high. DSN *could*
definitely use one more Southern Hemisphere site -- currently the Canberra
site is often a bottleneck -- perhaps in Argentina or South Africa. And
I'd think it would mildly benefit from a third, plus a third Northern
Hemisphere site somewhere like Japan, so that both hemispheres could have
round-the-clock coverage of most sky directions.

But the big requirement is not more sites, but more antennas. There's no
reason to spread the antennas out over a dozen sites, which will just run
up operations costs. What you want to do is not to commission a bunch
more sites, but to commission a bunch more big dishes at the same three or
four sites.

In addition, a
couple of satellites similar to the "Big Ear" spy sats should work AND have
the advantage of being able to access far more sky without bothering about
weather.

A space-based DSN has been studied repeatedly, but the extremely high
costs of mass, power, and maintenance up there have always led to the
conclusion that spending the same amount of money on the ground would give
better results.

The time when you really start thinking hard about orbital infrastructure
is when you take the next big jump up the frequency scale and go laser.
*Then* weather, even light cloud, bites hard. Still not a clear-cut win
for orbital receiving stations, but it makes them much more competitive.

--
rk, Just an OldEngineer
"Dealing properly with very rare events is one of the attributes that
distinguishes a design that is fit for safety-critical systems from one that
is not." -- John Rushby in "A Comparison of Bus Architectures for Safety-
Critical Embedded Systems," March 2003

In article ,
rk wrote:
The Apollo mission will be supported by earth-based
forces in the prime recovery areas and by the three planned
deep space instrumentation facilities (DSIF) tracking sta-
tions in Spain, Australia, and Texas.

And Texas?

Hmm, 1964... Given the lead time on such things, I would suspect this is
a document error rather than a change in plans. Certainly by Apollo 8,
the docs show the familiar three big tracking sites (plus a host of
smaller ones).
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Henry Spencer wrote:
In article , rk
wrote:

The Apollo mission will be supported by earth-based forces in the prime
recovery areas and by the three planned deep space instrumentation
facilities (DSIF) tracking sta- tions in Spain, Australia, and Texas.

And Texas?


Hmm, 1964... Given the lead time on such things, I would suspect this is a
document error rather than a change in plans. Certainly by Apollo 8, the
docs show the familiar three big tracking sites (plus a host of smaller
ones).

Correct. On 14 Mar 1962, NASA announced that DSIF stations with S-band
capability would be established at Goldstone, Calif., Woomera, Australia, and
near Johannesburg, South Africa. On 27 Nov 1962, NASA decided to look for a
site in Europe to replace the South African site. Operational capability was
only part of the criteria for site selection; effective technical and logistic
support and political stability had to be considered.

--
Dave Michelson

On Thu, 17 Jun 2004 02:45:25 GMT, Dave Michelson
wrote:

On 27 Nov 1962, NASA decided to look for a
site in Europe to replace the South African site.

....What were the criteria behind this site change?

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

"Dave Michelson" wrote in message
news:9B7Ac.772657$oR5.119678@pd7tw3no...

Correct. On 14 Mar 1962, NASA announced that DSIF stations with S-band
capability would be established at Goldstone, Calif., Woomera, Australia,
and
near Johannesburg, South Africa.

I expect they went for Canberra instead of Woomera when Woomera began
winding down with the missile tests. Plus Canberra is closer to
civilisation.

"OM" om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote
in message ...
On Thu, 17 Jun 2004 02:45:25 GMT, Dave Michelson
wrote:

On 27 Nov 1962, NASA decided to look for a
site in Europe to replace the South African site.

...What were the criteria behind this site change?

Apartheid?

On Thu, 17 Jun 2004 12:23:22 +0800, "Neil Gerace"
wrote:

"OM" om@our_blessed_lady_mary_of_the_holy_NASA_researc h_facility.org wrote
in message ...
On Thu, 17 Jun 2004 02:45:25 GMT, Dave Michelson
wrote:

On 27 Nov 1962, NASA decided to look for a
site in Europe to replace the South African site.

...What were the criteria behind this site change?

Apartheid?

....I'd have thought this had we been dealing with the late 60's -
early 70's.

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

OM wrote:
On Thu, 17 Jun 2004 02:45:25 GMT, Dave Michelson wrote:


On 27 Nov 1962, NASA decided to look for a site in Europe to replace the
South African site.

...What were the criteria behind this site change?

The South African site provided better, more complete coverage *and* already
had gear in place. See

http://deepspace.jpl.nasa.gov/dsn/history/dsn21.html

The Apollo chronology is fairly oblique except to note that NASA was willing
to accept some gaps in coverage in return for "more effective technical and
logistic support and political stability."

--
Dave Michelson

On Thu, 17 Jun 2004 06:10:15 GMT, Dave Michelson
wrote:

The Apollo chronology is fairly oblique except to note that NASA was willing
to accept some gaps in coverage in return for "more effective technical and
logistic support and political stability."

....This makes sense. ISTR a situation where one of the African
tracking stations hit a snag during Gemini when one of the local
tribes decided to go on a coup for ****s and giggles, and the site
crew had to deal with negotiating their way out of possibly being
served up for dinner at the next tribal campfire.

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr