Exploring the Unknown - NASA's History Office

As they look to the turn of the century and beyond, many people see increasingly
bleak prospects for the future. The pressures of population growth continue, particularly
in the less-developed countries. The people in these underdeveloped regions are surprisingly
young with an average age of about 15, and (hopefully) they will live to see several
generations of offspring. By contrast, in the developed countries like our own, the average
age is about 29 and steadily increasing. The developed world has nearly reached that
magic time when each couple replaces itself [2] [original placement of Figure 1] [3] with
only two offspring. Worldwide, however, that is not the case, and it is not likely to be in the
near future. As Figure 2 shows, the overwhelming majority of the world’s population is in
the underdeveloped countries; and within 100 years, their fractional share of world population
will nearly double. Of course, their populations will also increase in absolute
terms. The birth rates in many areas have recently undergone encouraging declines, but
so many of the people in the world are below the critical childbearing ages that the earth
is committed to supporting at least double, more likely triple, its present population. Most
experts are convinced that the best way to cut population growth rates is to develop a
healthy worldwide economy. Emerging affluence has always been accompanied by reductions
in population growth rates.
On Earth
Mount Palomar
Mount Everest
Frozen Orange Juice
Metal Soldering
Distillation of Metals
Refrigerator Manufacturer
Vacuum Bottles
TV Picture Tubes
Joining by
Organic Adhesives
Electronics Manufacture
Fusion Reactor
Pressure Vessels
Viton A. Gaskets and
All-Metal Joints
Best Vacuum Pumps
Heli Arc Welding
and Fluxless Brazing
Typical Space
Benefits
Pressure Levels
(Atmospheres)
10 -2
10 -4
10 -6
10 -8
10 -10
10 -12
10 -14
10 -16
Sea Level
• Highly Reflective
Sodium Coatings
• Ultra-Thin Films
• Unenclosed
Klystrons
In Space
Space
Biological
and Metal
Processing
Vacuum Welding
Unenclosed
Klystrons
Ambient Conditions 500KM
Echo Balloon
Wake Shield 500KM
Thin Film Vacuum Deposition
Figure 1. Environmental Properties in Space
EXPLORING THE UNKNOWN 519
On Earth
Eye Level
Firefighting
Observation Towers
Little Roundtop
at Gettysburg
Mount Palomar
Military Aerial
Reconnaissance
Crop Surveys
Commercial Jets
Viewing Area
(Fraction of the Globe)
10 -8
10 -7
10 -6
10 -5
10 -4
10 -3
10 -2
10 -1
1
• Nationwide
Communication Links
• Worldwide Observation
Platforms
• Accurate All-Weather
Navigation
100 N.MI. Orbit
Earth Resources Satellites
300 N.MI. Orbit
Navigation Satellites
12 Hour Orbit
Geosynchronous Orbit
(Communication Satellites)
One key to a healthy worldwide economy is expanded trade—especially trade that
results in a reasonable balance between imports and exports. The United States and other
industrialized countries sell large quantities of goods to the developing countries, but
In Space
On Earth G Levels In Space
Maximum Human
Tolerance
(Shock G’s)
Maximum Human
Tolerance
(Prolonged G’s)
Most
Manufacturing
Processes
Mount Palomar
Civil War
Minnie Ball
Manufacturer
Plastic Beads
for Reflecting
Highway Markers
10 2
10
10 -1
10 -2
10 -3
10 -4
10 -5
10 -6
• Large Perfect Crystals
• High-Strength
Permanent Magnets
• New Alloys and
Optical Glasses
Saturn V Max Loads
Shuttle Max Loads
Sea Level
Lunar Gravity
Minimum SPS Orbit
Transfer Loads
Space Crystal Growth
Space Purification/Separation
SPS Gravity Gradients
During Construction
100 N.MI. Orbit
Sounding Rockets
SPS Gravity Gradients
During Operation
Unmanned Orbital
Processing Facility