Sputnik only weighed 184-pounds and orbited the Earth every
90 minutes, but it was first and caught the Americans by complete
surprise. In November Sputnik was
followed by Sputnik II, which weighed more than 1,100-pounds and carried a live
dog, a startling achievement for the time.
From the launch of Sputnik I and II, both the Soviet Union and the United States embarked upon a
massive and expensive competition to be first in space, with the Soviet Union clearly in the lead in 1957. During the early days, of what the media
chose to call the “Space Race,” the Soviet Union
maintained a dominant lead over the United States establishing,
“firsts” in a number of varied space achievement categories. Ultimately,
through a series of very successful space probes and manned
space programs engineered by the United States, the United States
pulled ahead of the Soviet Union, went to the
Moon, and never relinquished the lead again.
Through the 1960s and 1970s my activities were re-directed
to the three manned programs: Mercury,
Gemini and Apollo; and most of the probes and satellites, including: Explorer,
Viking, Voyager, Skylab, and many of the
military programs, including: Polaris, Atlas, Minuteman.
During Mercury, my most vivid recollection was the small
size of the capsule. I am not a big
person (at least in those days, I wasn’t) yet, when visiting the St. Louis
Mercury site, I found the interior of the capsule very confining. It certainly was not suited for a
claustrophobic person. The Gemini
capsule was much larger, having been originally designed for three astronauts,
ultimately reduced to two, using more advanced engineering and space
knowledge. But it was Apollo that was
the most impressive, with it’s large sophisticated cabin for three
astronauts. Despite the improvements
incorporated from knowledge gained from the previous Mercury and Gemini flights
and the many Apollo test flights, the Apollo designs, by today’s standards,
were archaic. For example, Apollo had a
triple-redundant computer system to guarantee performance. What people outside
the space program, and some within the program, didn’t know was that the Apollo
computers were not as powerful as the commercial 486 designs in recent
use. Apollo was designed and constructed
with the design information that was then available.
During the prelaunch days of the Viking and Voyager
vessels, there were exhaustive tests performed on the proposed nuclear power sources. In long-term space voyages batteries are
inadequate power sources because of the distances involved. Only nuclear generators will provide the
re-charging that the batteries will need as they fly more distant from Earth
and the Sun becomes a dim light, ultimately becoming a speck of light, totally
inadequate to provide the radiant energy needed by the solar cells.
The major concern was that a mission would abort, the
nuclear power source would return to Earth in an uncontrolled terminal velocity
dive, and the resultant impact would burst the source and spread highly radioactive
plutonium over a wide area. This fear
was real and created a near-hysteria among activists who demanded the
termination of any space program using nuclear materials. But NASA was aware of the risk and set-about
to design a power source that would survive re-entry and impact.
Years before launch NASA designed and tested dummy nuclear
sources. These tests included the
jettisoning of the dummy sources from a launch vehicle and driving the sources
under rocket power back to Earth. The
resultant impact was far in excess of that which the power source would
experience during a real launch and abort.
The tests were conducted, and designs re-engineered and retested, until
at least three dummy sources had survived impact. This successful testing had little effect on
the demands of the activists. As
recently as the current planet probes, these activists are still raising their
hoary arguments and demanding termination of all nuclear powered programs.
During the period post-Sputnik and during the cold war,
after the United States had established itself in space, a decision was made to
over-fly the Soviet Union with satellites capable of taking high-resolution
pictures of selected Russian military installations. The problem was how to return the film
magazines to the United
States.
The Discoverer program resolved the difficulty by having the satellite
eject the magazine utilizing a coded signal while the satellite transited the
airspace between Hawaii
and the Pacific west coast. A special,
double-boomed aircraft would track the satellite and the descending magazine
(which had a long tail attached to a parachute), and catch the magazine in
mid-air with a specially designed arresting gear. The theory was that any magazines not
retrieved would fall into the ocean depths.
To my knowledge, only one magazine was lost. Despite the success of the program, a less
risky program was needed.
In the revised program, the satellite skin return signal was
replaced by a transponder which received the ground signal and, through the
transponder, returned an amplified signal to the signal originator, whether on
the ground or in the air. This permitted more efficient tracking. The satellite was equipped with electronic
storage of the pictures taken while over Russia, and the cameras were
improved versions allowing versatility in use and application. A special electronic device, which had
classified codes installed during manufacture, was added to the electronics
package. This device would only operate
after the proper codes were received by the satellite and compared to the installed
codes.
In operation, the satellite would be placed in an orbit
permitting it to pass over those parts of the Soviet Union
that were of interest. Upon receipt of a
coded signal the cameras would take the required numbers and types of pictures
and store the information electronically.
The satellite would continue in orbit until it arrived over the west
coast of the United States
at which time a coded ground signal would be directed to the satellite
instructing it to transmit the electronically stored photo images to a
designated ground station.
Line of sight transmissions could be repeated from first
contact in the west to last contact in the east. The coding of signals prevented unauthorized
access. Having disgorged its stored
information at high-speed in a burst of transmissions, the satellite continued in orbit
for another round of picture taking with each orbit covering a strip of the Soviet Union
adjacent to the strip just photographed.
These sequences of photographs could be maintained as long as the
satellite was operational.
The Transit satellite was a cheap, but successful
experiment. A compacted, plastic ball
was orbited and the ball inflated in Earth orbit. Though there were no instruments aboard, the
satellite permitted skin reflections to ground station transmissions. The most interesting part of Transit for me
was the ability of ground observers to see the satellite pass overhead at
night, reflecting sun light from its orbiting location. I had the privilege of watching Transit over-fly
New Jersey
many times.
Dyna-Soar was an early program that planned to fire a manned
vehicle into space and have it return to Earth using dynamic soaring for
re-entry. Sound familiar? Of course, that’s exactly how the shuttle
operates! The Dyna-Soar program was
canceled after much work had been completed because its design parameters had
been exceeded by other programs before it could be completed. The developed design information was not lost or wasted, but passed-on to the space programs
which followed.
Skylab was a success even though it suffered through some
early problems. Skylab 13 was the first US space
station. NASA had placed it in orbit properly, but for some reason after a time
the orbit began to slowly decay. The
solution was simple enough. They would
send a shuttle up with astronauts to correct the problem. But Skylab’s orbit unexpectedly started to
decay at an accelerated rate. NASA
couldn’t get a shuttle ready in time and the lab dropped into the Indian Ocean with some parts falling on Western Australia.
Mir was the Soviet Union’s
answer to Skylab. Mir was placed in
orbit in 1986, 12 years after the demise of Skylab. Mir was a fraction of the size of Skylab, but
was a technological improvement over the US design.
Mir had six docking ports. After a series of serious problems, including a collision with a Russian supply vessel, frequent oxygen leaks, power problems, loss of contact and other problems, a decision was made during the last half of 2000 to drop the space station into the ocean during the spring of 2001. The major fear of the controllers was that they may lose contact again and be unable to restore control. Rather than risk losing contact again and an uncontrolled re-entry, the Russian controllers dropped Mir into the ocean at a point of their choosing.
During my working years on the space program I was
privileged to meet Alan Shepard at a technical meeting in New York where he discussed his NASA
activities and, in particular, his flight in Freedom 7. During his later
flight on Apollo 14 in 1971 he became the fifth person to walk on the Moon,
having been preceded by Neil Armstrong (#1), Buzz Aldrin (#2), Conrad, Bean,
Shepard and Mitchell (#3-6). In 1969 the
crew of Apollo 11 left a plaque on the Moon’s surface, which read:
Here
Men from the Planet Earth
First
Set Foot Upon the Moon
July,
1969 AD
We
Came in Peace for All Mankind.
During July, 1975 the United States and the Soviet Union stopped arguing with each other long enough
to make the first international docking in space. Apollo 18, with a crew of 3: Thomas Stafford, Deke Slayton and Vance Brand docked with Soyuz 19 with a crew of 2: Aleksei Leonov and Valery Kubasov on July 16 through 18th in a cooperative program called the
Apollo-Soyuz Test Project (ASTP). Later,
in 1995, after the Soviet Union ceased to
exist, the United States
and Russia
participated in another space docking with the Mir/Shuttle venture.
Two flights of the most impressive performing planetary
probes were the Voyager missions. Voyager
1 was launched on September
5, 1977, and programmed to encounter Jupiter and Saturn, which it
did on March 5, 1979 and November
12, 1980, respectively.
Voyager 2 was launched on August 20,1977 to encounter Jupiter, Saturn, Uranus and
Neptune, which it did on July
9, 1979, August
26, 1981, January 8 and 27, 1986 and August
24, 1989, respectively.
Uranus was encountered twice during the mission. The amazing performance of these two probes
can best be realized by understanding the original mission and design.
Both probes had the mission of encountering the noted planets and
then, using the planets for the “sling-shot” effect, exiting the Solar system
where additional data would be collected and transmitted to Earth. The success of the probes outlasted the NASA
budget, however, which had been repeatedly reduced by the Clinton
Administration. After successfully
operating well into the end of the 20th century, lack of funds
forced NASA to shut down at least one, and probably both, Voyagers. Now dead, they silently continue their voyage
into deep space where they will not encounter another galaxy for thousands of
years.
The 1975 Viking program, following the successful series of
Mariner, Pioneer and Ranger probes in 1962 through 1973, provided the
information and experience needed to make Voyager the success that it was. In turn, Pioneer and Voyager contributed greatly to the
current Galileo spacecraft and the Mars vehicle design.
While my contribution to the space programs discussed above,
and many others, was relatively minor, there were tens of thousands of people
just like me, each contributing his or her small part which helped in the long
term to make the space programs of the United States a great success. Even if my views are considered by others to
be overstated, I believe them to be the truth.
One last note. None of the information included in this essay is classified. Those programs which were classified through the cold war have since lost their classification.
2001
LFC
No comments:
Post a Comment