Transcript Unmanned Space Programs

Unmanned Space
Programs
What is the difference?
Artificial Earth Satellite

A space vehicle built to orbit
the earth and perform a
specific function
Space Probe

Leaves the vicinity of Earth to
study planets, the sun, or
another aspect of the
heavens
Determining the Orbit of a Satellite

Three kinds of orbits around earth:
 1.
Low Earth orbit (weather & cell phones)
 2. Polar orbit (same light for comparison)
 3.Geosynchronous orbit (same viewpoint)

Two factors :
 1.
Gravity pulling it downward
 2. Its sideways speed
Artificial Earth Satellites

Two types:
 Scientific
satellites
 Applications satellites

Applications satellites:

Communications

Weather

Earth survey/resources

Navigation (GPS)

Surveillance (“spy”) satellites

Missile launch warning satellites

Temporary satellites (such as
the unmanned replenishment
vehicles for the International
Space Station)
How accurately
can the GPS
determine a
location on
earths surface?
WITHIN 3-5 METERS
A satellite in a
low Earth orbit is
moving ________
than a satellite in
a
geosynchronous*
orbit.
FASTER
*the orbital period of the
satellite is exactly the same as
the earth’s rotational period –
24 hours, and it is about 22,250
miles above the earth
Specialized Probes

Why they are “special”:

They visit comets or asteroids

They are placed in special orbits to observe the sun or some
other aspect of the heavens
A ________________is
placed between
two massive objects
at a location where
their gravities exactly
balance each other.
It orbits around this
point in space.
HALO ORBIT
Space Missions


Ways that probes may carry out their missions:

Fly by

Orbit

Crash into

Land on

Detach a lander

Leave the solar system completely (headed toward stars)
Planets,
moons,
asteroids,
comets,
etc.
Why missions to Mercury and Pluto are difficult:

Mercury – close to sun, high temperatures, strong radiation

Pluto – distant from earth, probe would require a large boost or special
propulsion system
Mercury

Ten years ago, on August 3, 2004, NASA’s MESSENGER (MErcury Surface,
Space ENvironment, GEochemistry, and Ranging) spacecraft blasted off
from Cape Canaveral, Florida, for a risky mission that would take the small
satellite dangerously close to Mercury’s surface, paving the way for an
ambitious study of the planet closest to the Sun.

The spacecraft traveled 4.9 billion miles (7.9 billion kilometers) — a journey
that included 15 trips around the Sun and flybys of Earth once, Venus
twice, and Mercury three times — before it was inserted into orbit around
its target planet in 2011.
Pluto: New Horizons

Operators at the Johns Hopkins University Applied
Physics Laboratory are preparing to “wake” the
spacecraft from electronic hibernation on Dec. 6, when
the probe will be more than 2.9 billion miles from Earth.

Distant observations of the Pluto system begin Jan. 15
and will continue until late July 2015; closest approach
to Pluto is July 14.