During the launch of one of the Syncom satellites, this is me
measuring the Range and Range Rate of the spacecraft. This is particularly
important as the distance to a geosynchronous space craft and the rate at which
that distance changes determines its geosynchronisity.
There
are only a finite number of satellites out there.
No doubt there are more in cue to be launched and positioned.
It would be interesting to know what the demands will be in the future
for channel space on those highflying communications devices.
With compression we can get much more on a single bird, but with
multicasting, Hi-Definition, etc., the need will gobble up bandwidth like a pack
of sharks on a feeding frenzy. I
often wonder if Dr. Harold Rosen or any of the rest of my associates with
Project Syncom ever thought what we were doing back in 1963-64 would ever evolve
into this? We sure thought it was
hot when we were able to tell within three meters of where Syncom II & III
were (at 22,300 miles) back in those days.
I wonder how much more accurate they are today?
[The
following was written in March 1998 and never published until now:]
Hughes,
Me and the "Birds"
The
year was 1962 and I was just finishing off my first hitch in Uncle Sam's Canoe
Club as a 2nd Class Electronics Technician.
With no particular job prospects and the economy not being in the best of
shape, my Dad suggested I do another tour, providing I could get an assignment
to my liking. When the assignment detailer said he had a duty station that
dealt with the space program, I had illusions of working with everything from
Buck Rogers' equipment to a James Bond spy-in-the-sky device.
It truly intrigued me so I raised my hand for another six.
I
was assigned to the U.S. Naval Research and Development Satellite Communications
Group with orders to work with Project Advent, a detachment assigned to a ship
to be commissioned at the Philadelphia Naval Ship Yard, USNS Kingsport.
I no sooner arrived in the City of Brotherly Love than I was handed
another set of orders back to California for school at the Space Technologies
Labs in El Segundo. It was while I
was at STL that I found out that Project Advent, a joint military satellite
effort, was canceled and was being replaced by Project Syncom. It seems that Advent was supposed to have been the first
geosynchronous satellite. When I
first heard this, I didn't have a clue as to what geosynchronous was, much less
spell it.
At
a distance of approximately 22,300 miles out in space, it would take an object
24 hours to orbit or rotate around the earth, thereby giving the impression that
it hovered over a given spot. It
wasn't hard to figure out that this would eliminate any expensive tracking
equipment. The antenna could
just point at the device and communicate. Another
advantage, at that altitude, each spacecraft saw 40% of the earth's surface.
It would only take three to cover the earth.
We
four STL students had a chance to compare notes and this is when I found out the
background as to why Advent got scrubbed. As
a joint military project, each branch had their own ideas as to what they wanted
in the spacecraft. At that point
there wasn't a booster big enough to get the payload off the ground.
It
wasn't GE, but Hughes that had a better idea and came to the rescue.
Dr. Harold Rosen, who headed up a group of engineers called Project
Syncom, had developed a very simple, lightweight transponder which would do
everything necessary to prove it all could be done and it all weighed only 78
pounds.
Before
I go on, not all communications satellites are equal.
The road to successful, reliable communications was long and involved.
The first attempt at communications aided by a device in space was with
Score, a relatively low orbit device
that, in 1958, transmitted a Christmas message from President Eisenhower to the
world. The Advanced Research
Projects Agency designed Score. The
second was Courier, an U.S. Army project. It
was launched in 1960 and was also a low orbit device, which received signals
from earth, taped them and retransmitted them when it was over the target area.
Echo-1, a 100-foot diameter metallic
surfaced ball, was launched on August 12, 1960.
Many transcontinental and transoceanic experiments and demonstrations
were made with this passive-reflector device until it lost much of its
efficiency as a radio-reflector due to the gas, which had inflated it, had
leaked out.
Telstar-1, launched on July 10, 1962 was
the most impressive device to date. It
was a joint AT&T - NASA project. The
first communications satellite NASA had been involved with.
Telstar-1 provided direct exchange of American and European television
programs during its six months of operation.
Other Telstars were launched, but because they had only a 90-minute
orbits, required expensive tracking equipment.
On
December 13, 1962, Relay-1 was launched. This
was a joint RCA - NASA project that had a 2-½ hour orbit.
Many of the same test were done with Relay as were done with Telstar, but
after being in service only a short time and due to power supply problems, NASA
found it impossible to use one of Relay-1's two amplifiers, so it was abandoned.
Enter
Project Advent, which, before completion, gave way to Syncom.
There were three agencies involved with Syncom: NASA, the United States
Army Satellite Communications Agency (USASCA) and Hughes.
USASCA was a joint military effort, who successfully saved most of the
training and equipment abandoned with the demise of Project Advent.
It was used with Syncom.
What
made Syncom unique, besides being geosynchronous, was a special design feature.
In its body was fitted a small rocket call the apogee motor, used to
inject the spacecraft into orbit when it reached its apogee at 22,300 miles of
the initial trajectory. Syncom was
also fitted with ten small vernier rockets used to correct further the final
velocity. Two nitrogen jets were
employed to obtain and maintain the required orientation and position above a
point on the ground.
Along
with forty some other sailors on the USNS Kingsport in Lagos, Nigeria,
I employed the skills I had learned at STL: Syncom-1 was launched on
February 14th, 1963. My job was to
determine the range or distance to the satellite and the rate at which this
range changed. Too close to the
earth and the orbit would be less than 24 hours.
Conversely, too far and it would take longer than 24 hours.
Drift was not acceptable unless it was on purpose to reposition the bird.
During the 5 hours it took to reach apogee, test were run and the
spacecraft worked fine. When the
apogee rocket was fired, that was the end of Syncom-1.
Long-range telescopes could see debris in geosynchronous orbit.
By
using wave fronts of predetermined, very accurately generated tones, we were
able, using Doppler techniques, to determine the distance to the spacecraft
within a meter or so. Not bad at 22,300 miles, but this accuracy would have been at
any distance using this technique. Hughes
was next door to where I worked. They
did all the command functions to the bird.
After
a brief retrofit of equipment and some rethinking, it was back to Africa and the
launch of Syncom II on July 26th, 1963. Everything
went according to plan. The bird
went into geosynchronous orbit and tests were conducted all hours of the day and
night. Before we left Nigeria, we hosted the first telephone call
between heads of state, Al Haji Sir Abubaker Blewa, Prime Minister of Nigeria
and President John F. Kennedy. It
is interesting to note that both were assassinated shortly thereafter while
still in office.
Because
we were portable, it was decided to test the fringes of the coverage area.
For that we went up into the Mediterranean Sea from Spain to Lebanon,
stopping in Italy. The earth
stations stateside we worked with were in Ft. Monmouth, and Lake Hurst, New
Jersey. Later we were to work with
Ft. Dix and Camp Roberts.
While
in Italy, I met my wife-to-be, while she was on vacation.
I mention this because the crew was permitted to make calls to their
friends and families through the bird, when our test periods were done.
We even had little cards like QSL card we sent to those we called.
I probably was the first person ever to court his girl through a
geosynchronous satellite.
The
only discrepancy with Syncom II was that since it was launched from Cape
Canaveral, some 28-degrees north latitude, the bird had a 28-degree north and
south excursion in a 24-hour period. This
was no problem, but it wasn't true synchronicity as was desired.
There
was a third bird in the wings and, rather than let it just sit there, it was
decided to put it up too. Kingsport went back for more retrofitting.
With all the new "mods" in place, we left the east coast, when
through the Panama Canal, stopped off in San Diego and Hawaii, finally taking
station on the tropical paradise of Guam. It
is interesting to note that on our way to Guam, we passed the AT&T Cable
ship, Long Lines while they were laying the first transpacific cable. What we
were doing would make the cable obsolete! We
used Syncom II and the AT&T pacific cable to help in the launch of Syncom
III.
Instead
of one transfer orbit, it was decided to use several and during the equatorial
crossings make corrections so the north/south excursions would be eliminated,
putting it into true synchronous orbit. Launched on August 19, 1964 from Cape
Kennedy, Syncom III didn't reach its "fixed" position until September
10th, after a series of maneuvers that put it in near perfect geosynchronous
orbit.
Many
hour of testing were done on both Syncom II and III.
Many "firsts" were logged on one or the other of those first
two working Syncoms. Inm
retrospect, it's sort of déjà vue: with the winter Olympics coming from
Japan (1998). We carried the first
summer Olympics, 34 years ago in 1964, through a geosynchronous satellite,
Syncom III for the first time. Those 1964 summer Olympics were held in
Japan too.
Hughes
is still in the Satellite business. As
for me, who knows, I do like my DSS and its several hundred channels, while I
set back and reaping the
fruits of those early labors.
END
Note: I will be
adding additional comments and some pictures from my own personal experiences at a later date. When I learn more
about how to build web pages, I may even include some tape recordings of the
actual launches of Syncom. Until then, please use these links below to learn about the
world's first geosynchronous satellite and a time in my life when I had one heck
of an experience and good time. Thanks for sharing in my adulation!
|
Satellites and
the Sun
Since the very first geosynchronous
satellite went up in 1963, users of these devices are subjected to a
unique phenomenon that occurs twice a year. Geosynchronous is a term used
to describe the orbit of satellites which rotate around the earth in a
24-hour period at an altitude of approximately 22,300 miles (~35,888 KM)
above the equator in synchronization with the rotation of the earth, there
by appearing to someone on the earth to be stationary or hovering at a
given spot above the earth. They are sometimes called Geo-stationary.
Because of their orbit, there are two times a year
all receive/transmit dishes and any given satellite are in alignment with
the sun. This takes place in the spring, usually in March and in the
fall,, usually September of the year. Because solar activity has many
kinds of radiation, radio noise across the entire spectrum being one of
them, it impacts satellite communications.
The effect usually lasts for about a week. It begins
its week-long cycle for only a brief (few seconds) period of time,
increasing daily to outages lasting as long as half an hour or more. It
then decreases in time until the phenomenon goes away for about six
months.
The only way to avoid this kind of outage from the
satellite you normally use is to switch to a different satellite at a very
different orbit during the outage, if you have that option available; if
not there is nothing you can do! These solar outages will occur at
different times of the day from any one given location on the earth with
satellites “parked” in different orbits; the closer together orbits,
the more concurrent would be the effect in comparison.
Feel free to e-mail any other questions of this type
to: webmaster@tech-notes.tv
|
Links
http://www.fredonia.edu/department/communication/schwalbe/cm350/tsld173.htm
http://www.fredonia.edu/department/communication/schwalbe/cm350/sld167.htm
http://www.tbs-satellite.com/tse/online/sat_syncom_2.html
http://www.aipress.com/jackpages/syncom.html
http://www.tbs-satellite.com/tse/online/sat_syncom_3.html
http://roland.lerc.nasa.gov/~dglover/sat/syncom.html
http://www.rocketry.com/mwade/craft/syncom.htm
http://satamerica.com/orbit7.html
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