1. Space History:
Voyager and More
Galaxy Forum
September 22,2012
Thomas P. Armstrong

2. The US Response to USSR Sputnik 1 was Explorer 1.
Launched January 31, 1958
(William Pickering, James VanAllen, & Werner VonBraun shown with flight spare.)

3. Sputnik I
The first Earth
satellite.
•
Launched by the USSR on
October 4, 1957
•
22.5 inches in diameter
•
184 pounds
•
Highest altitude 569 miles
•
Transmitted for 23 days
•
Radio frequencies were 20
and 40 Megacycles—
received by amateurs all over
the world
•
Established the USSR as the
leader in the “Space Race” to
the great embarrassment of
the USA

4. •
When Prof.
VanAllen was
asked by a
reporter “What
does the
VanAllen belt
look like?” his
reply was “Tan,
leather, with a
brass buckle.”

5. Explorer I rates show that magnetic field controls the
radiation and therefore confines it!!
•
Versus altitude •
Versus Magnetic
Different longitudes
Field shows a
•
much simpler graph

6. Explorer I rates show that magnetic field controls the
radiation and therefore confines it!!
•
Versus altitude •
Versus Magnetic
Different longitudes
Field shows a
•
much simpler graph

7. What causes trapped radiation?
1. Natural electrical processes resulting from the
impact of solar “wind” (outflowing ionized solar
atmosphere) on planetary magnetic fields.
2. Capture of electrons and protons resulting from
“Galactic Cosmic Rays” impacting on planetary
atmospheres.
3. Planets with magnetic fields (Earth, Jupiter, Saturn,
Uranus, and Neptune) all have trapped radiation.

8. Why worry about trapped radiation?
•
Radiation exposure is unhealthy for humans which
limits astronaut operations in Earth orbit above
about 500 km altitude.
•
Radiation can damage or destroy spacecraft solar
cells and electronics limiting the operating life of
systems. Communication satellites and GPS operate
in high exposure regions.
•
Trapped radiation connects interplanetary
disturbances produced by the Sun to changes in
magnetic field at the Earth’s surface that sometimes
produce power and communication failures.

9. Why people should care about
space-derived knowledge
1. There is a chance that Earth could be struck again by an asteroid-
sized object that could end civilization. Warning and preparation
could allow civilization to survive. Space operations will likely be
required to reduce the effects of a collision.
2. People require the Earth’s environment to survive. Global change
occurs. Intelligent use of Earth’s resources informed by space
observations may improve and extend the future of humanity.
3. An important question in the human experience that may be
answered by observations beyond Earth is the occurrence of
extraterrestrial life, especially intelligent life. (Are “they” smarter
than we are?)

10. Solar system objects that have hit the Earth and those that might
Hiroshima
Smaller but more frequent
Larger but less frequent Dinosaur Extinction

11. What do these threats look like?

15. Earth-our home-seen from space
From Apollo 17 L.E.O. composite

16. North America by night from space

17. Europe by night from space

18. The BIG question(s)
1. Is Earth the only planet in the solar system
with life?
2. Is the Sun the only star with a planet that can
sustain life?
3. What is “dark matter”?
4. What is “dark energy”?

19. 1. Is Earth the only planet in the
solar system with life?
•
Robot explorations of Mars have not yet revealed any
evidence of exobiology.
•
Atmospheric probes of Venus, Jupiter, and Titan have
been made. No evidence of exobiological processes
has been found.
•
Europa and Enceladus have liquid water under icy
surfaces and are considered as possible habitats.
•
The search for life motivates human exploration of
Mars.

20. 2. Is the Sun the only star with a
planet that can sustain life?
•
Observations from the Kepler spacecraft show many
multi-planet stellar systems in the galaxy.
•
Preliminary estimates suggest there may be more
planets than stars in the galaxy.
•
A search for “Goldilocks” planets is proceeding with
several candidates reported.
•
NASA’s James R. Webb telescope in development will
allow spectroscopic studies of “Goldilocks” planets to
obtain atmospheric composition. Biological activity
might be detected by such observations.

21. Summary from the Kepler Mission

22. Mars to Earth sized planets
discovered by Kepler

23. Kepler 22b- a habitable zone
planet
“Goldilocks”