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Space Topics: Asteroids and CometsMissions to Asteroids and CometsInternational Cometary Explorer (ICE) - Vega 1 - Vega 2 - Sakigake - Suisei - Giotto - Galileo - Near Earth Asteroid Rendezvous (NEAR) - Deep Space 1 - Stardust - Comet Nucleus Tour (CONTOUR) - Deep Impact - Hayabusa (MUSES-C) - Rosetta - Dawn
International Cometary Explorer (ICE)
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Sakigake
ISAS |
Sakigake
Comet 1P/Halley flyby (Institute of Space and Aeronautical Science (ISAS))
Launch: January 8,1985
Flyby: March 11, 1986
Sakigake (which translates to 'Pioneer') was a prototype
spacecraft launched by the Japanese space agency ISAS. It successfully flew
within 7 million kilometers (4 million miles) of Halley's comet. The spacecraft
was equipped with 3 instruments to measure plasma wave spectra, solar wind
ions, and interplanetary magnetic fields. An extended mission was planned,
including flybys of comet 45P/Honda-Mrkos-Pajdusakova in 1996 and comet 21P/Giacobini-Zinner
in 1998. Unfortunately, controllers
lost contact with the spacecraft on November 15, 1995.
Suisei
ISAS |
Suisei
Comet 1P/Halley flyby (Institute of Space and Aeronautical Science (ISAS))
Launch: March 18, 1985
Flyby: March 8, 1986
Suisei (which translates to ‘Comet') was identical
to Sakigake apart from its payload: an ultraviolet (UV) imaging system and
a solar wind instrument. Suisei began UV observations in November 1985, generating
up to 6 images per day. The spacecraft encountered Comet 1P/Halley at a distance
of 151,000 kilometers (94,000 miles). ISAS had decided during 1987 to guide
Suisei to a November 24, 1998 encounter with 21P/Giacobini-Zinner, but due
to depletion of the hydrazine, this, as well as plans to fly within several
million kilometers of comet 55P/Tempel-Tuttle on February 28, 1998, were cancelled.
Giotto
ESA |
Giotto
comets 1P/Halley and 26P/Grigg-Skjellerup flyby (ESA)
Launch: July 2, 1985
Halley flyby: March 13, 1986
Grigg-Skjellerup flyby: July 10, 1992
Giotto flew by Halley at a distance
596 kilometers (370 miles). All experiments performed well and returned a
wealth of new scientific results, of which perhaps the most important was
the clear identification of the cometary nucleus. During an extended mission,
the spacecraft successfully encountered comet Grigg-Skjellerup at a distance
of 200 kilometers (120 miles). Giotto operations were officially terminated
on July 23, 1992.
Galileo
NASA/JPL |
Galileo
Flyby of asteroids 951 Gaspra and 243 Ida; Jupiter orbiter (NASA)
Launch: October 18, 1989
Gaspra flyby: October 29, 1991
Ida/Dactyl flyby: August 28, 1993
Witnessed Shoemaker-Levy crash: July 1994
Galileo accomplished the first
ever asteroid flybys as it traveled through the Main Belt on its way to Jupiter. It passed within 1,600 kilometers
(1,000 miles) of Gaspra and 2,400 kilometers (1,500 miles) of Ida. Galileo
made the surprising discovery that Ida has a tiny satellite, which was later
named Dactyl. As Galileo approached its insertion into Jupiter orbit,
it happened to be the right place in the right time to observe comet Shoemaker-Levy
9 break up and crash into Jupiter. Galileo was the only observatory
that had a direct view of the impact, which happened on Jupiter’s night
side; Earth-based telescopes had to wait until Jupiter’s rotation brought
the impact zone into view hours later.
NEAR
NASA / JHU APL |
Near Earth Asteroid Rendezvous (NEAR)
Asteroid 433 Eros orbiter (eventually used as a lander!) (NASA)
Launch: February 17, 1996
Eros arrival: February 14, 2000
Eros landing: February 12, 2001
During its yearlong mission, NEAR gathered
10 times more data than originally planned. On February 12, 2001, with
its fuel and funding nearly depleted, mission planners tried the unprecedented
maneuver of landing the orbiter on Eros. With fragile solar panels and protruding
antennae, NEAR was never intended to be a lander. However, controllers successfully
brought the spacecraft to a gentle 1.9 meter-per-second (4 miles-per-hour)
touchdown onto the rocky surface, taking 69 images during the final descent.
The spacecraft continued to function even after it landed. NEAR was officially
shut down on February 28, 2001.
Deep Space 1
NASA |
Deep Space 1
Flybys of asteroid 9969 Braille and comet 19P/Borrelly (NASA)
Launch: October 24, 1998
Braille flyby: July 28, 1999
Borrelly flyby: September 22, 2001
Deep Space 1 was a demonstration probe
designed to test new technologies such as ion propulsion. The spacecraft flew
by asteroid 9969 Braille, which was named through a Planetary Society-run
contest, within 15 kilometers (9 miles) of the asteroid's surface. With all
systems still operating at the end of its primary mission in September 1999,
engineers decided to extend the mission and attempt a flyby of comet 19P/Borrelly.
By the time Deep Space 1 reached Borrelly, it had lasted 3 times longer than
expected. It flew within 2,200 kilometers (1,400 miles) of the comet, providing
the most detailed images of a comet's nucleus yet seen. With its fuel almost
gone and its instruments in varying states of disrepair, communication with
the spacecraft was terminated in December 2001.
Stardust
NASA / JPL |
Stardust
Flyby and coma sample return from comet P/Wild 2
Launch: February 7, 1999
Wild 2 flyby: January 2, 2004
Sample return: January 15, 2006
When Stardust flew by Wild 2, it collected
samples of dust and volatiles from the comet's coma as well as images and
other data. Other objectives of the mission include collecting samples
of interstellar dust grains, imaging the comet nucleus, and conducting
preliminary analysis of the composition of the cometary dust particles.
It returned the samples to Earth on January 15, 2006; they are now undergoing
detailed analyses of their elemental, isotopic, mineralogical, chemical,
and biogenic properties. The aerogel collector plates proved to be full
of cometary material, surpassing the science team's expectations. The interstellar
dust grains will be much harder to find, and the public has been invited
to join the search in a project called Stardust@home.
CONTOUR
NASA / JHU APL |
Comet Nucleus Tour (CONTOUR)
Failed multi-comet flyby (NASA)
Launch: July 3, 2002
CONTOUR was lost August 15, 2002, when the spacecraft
failed to contact Earth shortly after a scheduled firing of its main rocket
motor. Investigation revealed that the spacecraft broke apart toward the
end of the rocket motor firing. The
spacecraft had been scheduled to fly by at least three comets: comet 2P/Encke
in 2003, continuing with 29P/Schwassmann-Wachmann in 2006, and 6P/d'Arrest
in 2008.
Deep Impact
NASA / JPL |
Deep Impact
Flyby and impact into comet 9P/Tempel 1
Launch: January 12, 2005
Tempel 1 impact and flyby: July 4, 2005
One day prior to its flyby of Tempel
1, Deep Impact released a 364-kilogram (800-pound) impactor onto a collision
course with the comet. The impactor
captured images all the way down to its 10.2 kilometer-per-second (22,800
mile-per-hour) impact with Tempel 1. The flyby spacecraft captured amazing
views of the impact from a safe distance as every large telescope on Earth
was also pointed at the comet. With its primary mission over, Deep Impact
is now on a course that will lead it to fly by Earth in December 2007;
the flyby could be used as a gravity assist to steer Deep Impact toward a
flyby of comet 85P/Boethin in 2008.
Hayabusa
JAXA |
Hayabusa (MUSES-C)
Orbiter and sample return from asteroid Itokawa (1998 SF36) (ISAS)
Launch: May 9, 2003
Itokawa arrival: September 2005
Itokawa departure: scheduled for 2007
Sample return: 2010
The primary scientific objective of the Hayabusa
mission is to collect surface samples from an asteroid and return the samples
to Earth for analysis. Upon arrival at the small asteroid Itokawa, Hayabusa
surveyed the surface from a distance of about 20 kilometers (12 miles). It
deployed a hopper named "Minerva" on November 12, 2005, but the hopper
missed the asteroid. It did successfully drop a target marker containing
880,000 names to the surface, and then followed the marker down for two
landing attempts. The landing attempts left the spacecraft badly damaged,
and it is unknown whether any sample material was collected. Controllers
are still in contact with the spacecraft and are holding out hope that
it will be able to return to Earth, whatever it carries.
Rosetta
DASA / Rosetta |
Rosetta
Comet 67P/Churyumov-Gerasimenko orbiter and lander (ESA)
Launch: March 2, 2004
Churyumov-Gerasimenko arrival: 2014
Rosetta's original goal was comet 46P/Wirtanen, but launch delays required
a rerouting to 67P/Churyumov-Gerasimenko. During its 10-year cruise,
it will fly by at least two asteroids. The current plans involve flybys
of asteroid 2867 Steins on September 5, 2008 and 21 Lutetia on July 10,
2010. Once
at Churyumov-Gerasimenko, a small lander, Philae, will drop down to the
surface of the comet.
Dawn
NASA / JPL |
Dawn
Asteroid 4 Vesta and dwarf planet 1 Ceres orbiter (NASA)
Launch: September 27, 2007
Dawn will orbit the two largest asteroids in the main belt, reaching 4
Vesta in July 2011 and 1 Ceres in August 2014. After being ordered to stand down indefinitely, the mission has been reinstated and is going forward.
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