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Deep Impact was the first mission to impact on a comet. NASA's Deep Impact
Spacecraft was launched on 12th January 2005 aboard a Delta II
from Cape Canaveral in Florida, USA. It took 6 months to
reach its comet target - Comet Tempel 1. Deep Impact rendezvoused Comet Tempel 1 on July 4, 2005.
Artist
Pat Rawlings gives us a look at the moment of impact and the
forming of the crater.
Credit: NASA
The purpose
of the Deep Impact mission was to study the structure of cometary nuclei, the comet's structure and makeup (both its
surface and deep inside). The material seen may help to explain
how our solar system was formed and help to
understand the chemical composition of comets. The size of
pieces knocked will be used to determine the comet’s strength.
Deep Impact
Spacecraft is actually two spacecraft in one:
(1). A flyby
ship (mothership) - Instruments
on the Deep Impact mothership will observe and capture images on approach, when
the impactor hits and during the flyby. The Deep Impact
Spaceraft ( mothership) will pass by Comet Tempel 1 from a a safe distance
of 500km (300miles).
After release
the impact will target an illuminated area and not a dark area. The
mothership will perform an evasive manoeuvre, plotting a trajectory
to fly past the comet shortly after the impact.
(2). Drop-probe impactor: The Impactor weighs 370kg (800 pound)
and is 1m in diameter and 0.8m tall. It will use autonomous
navigation computer, cameras and a propulsion system to guide
itself toward a suitable impact point that is well lit.
To reduce the
chance of the impactor’s materials being mistaken for cometary
components, mission scientists built the impactor using
substances unlikely to occur naturally in a comet ?it’s
half copper by weight, for example.
Mission
Deep Impact
probe cruised for 6 months before intercepting the comet
beyond Earth’s orbit. On July 4, 2005, the probe released
a self-guiding, camera-carrying kamikaze impactor to the surface
of Comet Tempel 1
at 37,000kph creating a crater. Before, during and after the
collision, Deep Impact Spacecraft (motheship) collected data and
pictures. It was protected from flying debris by a dust
shield.
Deep
Impact History
NASA's Deep
Impact has cost $267 million US dollars. The Deep Impact mission
is managed for NASA by the Jet Propulsion Laboratory, Pasadena,
California. The Principal Investigator is Dr. Michael A'Hearn, a
prominent comet scientist from the University of Maryland. Ball
Aerospace and Technologies Corporation, Boulder, Colorado, is
responsible for all flight hardware. Deep Impact is first
planetary science spacecraft for Ball Aerospace.
* In July
1999, NASA selected Deep Impact to be the eighth Discovery
mission.
* Work on the
Deep Impact mission began in January 2000.
* The NASA
Deep Impact Spacecraft was launched on 12th January 2005 from Cape
Canaveral in Florida for a 431 million km voyage that will take
it on a collision course with the Tempel 1 comet.
* Two months
before the encounter, Deep Impact Spacecraft will commence its
scientific observations - how the comet nucleus rotates and
examine the jets of gas and dust streaming away from Comet
Tempel 1.
Aftermath
- Viewing the Comet
Earth
Ground based telescopes will monitor the comet before and after
the collision. Space Observations will be made by the Hubble Space Telescope and Spitzer
Space Telescope.
What will the
impact look like?
How Tempel 1
will react to the impact is unknown, but scientists do not
believe the comet will break up. The size of the crater might be
as big as a house or up to a football stadium. The collision
will have an undetectably small effect on the comet’s orbit.
The expanding
dust cloud should increase the comet’s visual brightness and
might be detectable by backyard telescopes. We'll have to wait. Stay Tuned!
If the
mission is successful, the images/pictures taken will be the
highest resolution taken of a nucleus of a comet.
Tempel 1
Comet Facts
Comet Tempel 1 was discovered
on 3 April 1867 by Ernst Wilhelm Leberecht Tempel in Marseilles,
France. Comet Tempel 1 currently circles the Sun every 5.5
years. It's orbit lies between Mars and Jupiter. At impact Deep
Impact Spacecraft will be 130 million km from Planet Earth.
The comet is a short-period
comet, which means it orbits the Sun in an elliptic (oval)
orbit, between Mars and Jupiter, every 5.5 years. It's nucleus
is thought to have a 6.5km diameter and to consist of water and
carbon. From oberservations made to date, the exact size and
shape of the nucleus of Tempel 1 is unclear.
Did
you know?
- Deep Impact
Spacecraft maybe the ultimate display on America's 4th July
Celebrations, which is Independence Day.
- Comets are
basically frozen ice balls which circle the Sun. They may have played a vital role in bringing water and carbon-based
molecules to Earth - the essential ingredients for life to
begin.
- A comet or asteroid is believed by a many
scientists to have caused the impact that changed Earth's
climate and wiped out dinosaurs, 65 million years ago.
- Comets offer
clues to some of the most fundamental questions about conditions
when the planets were forming, more than four billion years ago.
- It's been
done in films, but this is the first real attempt to impact a
comet.
- There was a
movie called Deep Impact.
- NASA's Stardust Spacecraft flew
past Comet Wild 2 in January 2004, catching dust particles for
return to Earth in 2006. Current mission Rosetta mission is
flying to comet Churyumov-Gerasimenko where a lander will land
on it.
- The impact
will be the astronomical equivalent of a mosquito into the path
of a Boeing 777 aeroplane - altering the comet's velocity by
just 0.0001 millimetres per second.
- Every time a
comet goes around the Sun, the surface gets heated and as a
result changes the near surface. The impact may show how
different the surface is from what's inside.
Related
Space Books
Comet by
Carl Sagan, Ann Druyan (Contributor)
From Amazon.com,
Amazon.co.uk
Impact!: The
Threat of Comets and Asteroids
by Gerrit L. Verschuur
From Amazon.com,
Amazon.co.uk
Deep
Impact Links:
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