A space probe is a scientific space exploration mission in which a spacecraft leaves Earth and explores space. It may approach the Moon; enter interplanetary space; flyby, orbit or land on other planetary bodies; or approach interstellar space. Space probes are a form of robotic spacecraft. The Voyager 1 is one of the most famous space probes.
See list of probes by operational status for a list of active probes; the space agencies of the USSR (now Russia and Ukraine), the United States, the European Union, Japan, China and India have in the aggregate launched probes to several planets and moons of the solar system as well as to a number of asteroids and comets.
Interplanetary trajectories 
Once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earth's orbit. To reach another planet, the simplest practical method is a Hohmann transfer orbit. More complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions (such as those with high inclination changes) can only be performed, within the limits of modern propulsion, using gravitational slingshots. A technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network.
Some notable probes 
First unmanned robotic sample return probe from the Moon.
First rover on Moon. It landed in the moon in 1970
First probe to Mercury.
Probe from the Soviet Union was the first man-made spacecraft to impact on another planet (Venus).
Venera 7 
Mariner 9 
First soft landing on Mars the planet(between 1960 and 1973).
First successful rover on Mars.
Spirit and Opportunity 
The Mars Exploration Rovers, Spirit and Opportunity surface and geology, and searched for clues to past water activity on Mars. They were each launched in 2003 and landed in 2004. Communication with Spirit stopped on sol 2210 (March 22, 2010). JPL continued to attempt to regain contact until May 24, 2011, when NASA announced that efforts to communicate with the unresponsive rover had ended. Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin, after traversing 13 miles from Victoria crater, over a three-year period. As of January 16, 2012, Opportunity has lasted for more than eight years on Mars — although the rovers were intended to last only three months.
The first dedicated missions to a comet; in this case, to Halley's Comet during its 1985-86 journey through the inner solar system. It was also the first massive international coordination of space probes on an interplanetary mission, with probes specifically launched by the Soviet (now Russian) Space Agency, European Space Agency and Japan's ISAS (now integrated with NASDA to JAXA).
Original a solar observatory in the International Sun-Earth Explorer series, it was sent into solar orbit to make the first close observations of a comet, Comet Giacobini-Zinner, in 1985 as a prelude to studies of Halley's Comet.
Two Russian/French spacecraft. They dropped landers and balloons (first weather ballons deployed on another planet) at Venus before their rendezvous with Halley's Comet.
This Japanese probe was the first non-US, non-Soviet interplanetary probe.
A second Japanese probe, it made ultraviolet wavelength observations of the comet.
The first space probe to penetrate a comet's coma and take close-up images of its nucleus.
First solar wind sample return probe from sun-earth L1.
First sample return probe from comet tail.
First probe to asteroid with landing.
First sample return probe from asteroid.
First probe to Jupiter.
First probe to flyby two planets and first probe to Saturn.
Voyager 1 
Voyager 1 is a 733-kilogram probe launched September 5, 1977. It is currently[update] still operational, making it the longest-lasting mission of the U.S. National Aeronautics and Space Administration (NASA). It visited Jupiter and Saturn and was the first probe to provide detailed images of the moons of these planets.
Voyager 1 is the farthest human-made object from Earth, traveling away from both the Earth and the Sun at a relatively faster speed than any other probe. As of July 23, 2010, Voyager 1 is over 17 terameters (1.7×1013 meters, or 1.7×1010 km, 110 AU, 15.7 light-hours, or 10.5 billion miles) from the Sun.
Voyager 2 
First landing on Titan
First probe to be launched to Pluto
First probe to Jupiter without atomic battery, launched August 8, 2011.
Beyond the Solar System 
Along with Pioneer 10, Pioneer 11, and its sister space probe Voyager 2, Voyager 1 is now an interstellar probe. Voyager 1 and Voyager 2 have both achieved solar escape velocity, meaning that their trajectories will not return them to the solar system.
Probe imagers 
Examples of space probe imaging telescope/cameras (focused on visible spectrum).
|Mars Reconnaissance Orbiter—HiRISE||50 cm (19.7″)||R/C||Mars orbit||2005|
|Mars Global Surveyor—MOC||35 cm (13.8″)||R/C||Mars orbit||1996–2006|
|New Horizons—LORRI||20.8 cm (8.2″)||R/C||Space (33+ AU from Earth)||2006|
|Lunar Reconnaissance Orbiter LROC-NAC||19.5 cm (7.68″)||Reflector||Lunar orbit||2009|
|Cassini—ISS-NAC||19 cm (7.5″)||Reflector||Saturn orbit||2004|
|Galileo - Solid State Imager||17.65 cm (6.95″)||Reflector||Jupiter||1989-2003|
|Voyager 1/2, ISS-NAC||17.6 cm (6.92″)||Catadioptric||Space||1977|
|Mariner 10 - TV Photo Experiment (x2)||15 cm (5.9″)||Reflector||Space||1973-1975|
|Deep Space 1—MICAS||10 cm ( 3.94″)||Reflector||Solar orbit||1998-2001|
|Voyager 1/2, ISS-WAC||6 cm (2.36″)||Lens||Space||1977|
|Cassini—ISS-WAC||5.7 cm (2.2″)||Lens||Saturn orbit||2004|
|MESSENGER MDIS-WAC||3 cm (1.18″)||Lens||Mercury orbit||2004|
|MESSENGER MDIS-NAC||2.5 cm (0.98″)||R/C||Mercury orbit||2004|
|Dawn Framing Camera (FC1/FC2)||2 cm (0.8″)||Lens||Asteroid belt||2007|
Image forming systems on space probes typically have a multitude of specifications, but aperture can be useful because it constrains the best diffraction limit and light gathering area.
See also 
- Space capsule
- Viking program 1975-1982
- Pioneer 10 1972-2003
- Mariner 10 1973-1975
- Space exploration
- U.S. Space Exploration History on U.S. Stamps
- Interstellar probe
- Unmanned spacecraft
Further reading 
- McNutt, et al. - Radioisotope Electric Propulsion (2006) - NASA Glenn Research Center (includes Centaur orbiter mission)
- Scott W. Benson - Solar Power for Outer Planets Study (2007) - NASA Glenn Research Center
- Next exit 0.5 Million Kilometers
- September 30 – October 05, 2010 Spirit Remains Silent at Troy NASA. 2010-10-05.
- A.J.S. Rayl Mars Exploration Rovers Update Planetary Society 30 November 2010
- Webster, Guy (25 May 2011). "NASA's Spirit Rover Completes Mission on Mars". NASA. Retrieved 2011-10-12.
- "NASA Concludes Attempts to Contact Mars Rover Spirit". NASA. Retrieved 25 May 2011.
- Chang, Kenneth (May 24, 2011). "NASA to Abandon Mars Spirit Rover". New York Times.
- NASA Mars Rover Arrives at New Site on Martian Surface Jet Propulsion Laboratory, 10 August 2011.
- "Where Comets Emit Dust: Scientists Identify the Active Regions on the Surface of Comets" - ScienceDaily (Apr. 29, 2010)
- "NASA Voyager 1 Encounters New Region in Deep Space". NASA.
- Voyager - Mission - Interstellar Mission
- Mars Global Surveyor
- eoportal - LRO (Lunar Reconnaissance Orbiter) - LROC
- Cassini Solstice Mission: ISS
- Basics of Spaceflight (Ch. 12) - NASA/JPL
- astronautix - voyager
- NASA/NSSDC - Mariner 10 - Television Photography
- NASA DS1
- Mercury Dual Imaging System (MDIS) - NASA/NSSDC
- Sierks, et al. - The Dawn Framing Camera: A Telescope En Route to the Asteroid Belt - MPS/DLR/IDA
- Deep Space: The NASA Mission Reports / edited by Robert Godwin (2005) ISBN 1-894959-15-9
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