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Galileo Spacecraft Facts
2941/ On its first orbit
around Jupiter, the Galileo spacecraft reached a maximum distance
from Jupiter of about 20 million kilometres. This is nearly
half the distance between the orbits of Earth and Venus, Earth's
closest planetary neighbou
2942/ Jupiter's volume
is about 1,400 times that of the Earth. In fact, its volume
is half again bigger than all of the Solar System's other
planets, moons, asteroids, and comets combined.
2943/ Batteries only
get you so far in outer space. The Galileo orbiter carries
two radioisotope thermoelectric generators (RTGs), which are
used to generate electrical power on board the spacecraft.
There are 7.8 kilograms (17.2 pounds) of Plutonium-238 in
each RTG.
2944/ After travelling
2.4 billion miles in just over 6 years to reach Jupiter, Galileo
missed its target at the Jovian moon Io by only 67 miles.
That's like shooting an arrow from Los Angeles at a bull's-eye
in New York and missing by only 6 inches!
2945/ Galileo's roots
date back to an early recommendation for an atmospheric probe
that would explore Jupiter's atmosphere down to pressure levels
100 times that of Earth at sea level. This proposal eventually
became JOP (for Jupiter Orbiter Probe), which then eventually
became Galileo.
2946/ When the Galileo
Probe entered Jupiter's atmosphere, it was traveling at a
speed of 106,000 miles per hour -- the fastest impact speed
ever achieved by a man- made object. At that speed, one could
drive around the Earth at the equator in 14 minutes (assuming
there were bridges across all the oceans) or to the Moon and
back in only 5 hours!
2947/ On its journey
from Earth to Jupiter, Galileo traveled 2.4 billion miles.
Along the way, about 67 gallons of fuel from the propulsion
system were used to control Galileo's flight path and to keep
its antenna pointed at Earth. That's equivalent to getting
36 million miles per gallon! With that kind of mileage, one
would use up only 4 tablespoons of gasoline to drive to the
Moon and back!
2948/ Galileo travels
at an average speed of 44,000 miles per hour. At that speed,
one could drive around the Earth at the equator (assuming
there were bridges across all the oceans) in just over half
an hour, or to the Moon and back in only 11 hours!
2949/ Jupiter has some
truly high velocity winds-- they blow at speed as high as
260 miles per hour at Jupiter's cloud tops!
2950/ Magnetic fields
can be powerful entities. Jupiter's magnetosphere strips away
1 ton of material from Io a second. Io's orbital motion through
Jupiter's magnetosphere generates electricity--an electric
current of 3 million amps!
2951/ Galileo passed
about 100 km closer to Io than planned. This meant that the
gravity assist from Io slowed Galileo's speed more than was
planned, putting the spacecraft into a shorter orbit around
Jupiter than expected.
2952/ Galileo Galilei's
discovered Jupiter's moons Io, Europa, Callisto and Ganymede.
2953/ The four largest
moons in the Jovian system are called the Galilean satellites,
in honor of their discoverer.
2954/ Because the asteroid
Gaspra is so small (about 19 x 12 x 11 kilometers, or 12 x
7.5 x 7 miles), its surface gravitational force is two thousand
times smaller than that of the Earth's, yielding an escape
speed of only 10 meters per second (22 miles per hour); an
Olympic-caliber sprinter could run himself into orbit! A 200
pound person would weigh 0.1 pounds!
2955/ When the Galileo
Photopolarimeter Radiometer detected the flashes of light
caused by Comet Shoemaker-Levy 9 crashing into Jupiter in
July 1994, it was using a 4 inch telescope, and it was as
far away from Jupiter as Mars is from the Sun.
2956/ Although Galileo
Galilei was a college dropout, he went on to become a respected
professor.
2957/ The Great Red Spot
has been seen since the 17th century. It is thought to be
a large storm system and is wider than two Earths.
2958/ Jupiter has 16
known moons. Of the four largest, Europa is just slightly
smaller than our Moon, while Io, Ganymede, and Callisto are
larger than our Moon. In fact, Ganymede is larger than the
planet Mercury.
2959/ The amount of power
being transmitted out of the spacecraft radio is about the
same as that from a refrigerator lightbulb - about 20 watts.
2960/ Jupiter has no
solid surface; it is composed almost entirely of hydrogen
and helium and is hot enough inside to vaporize all elements.
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