The following list is only a series of vehicles related to interplanetary scientific research, and is far from a complete list of vehicles.
Past Missions
Luna 2 Luna 2
hit the Moon in 1959 (USSR)
Luna 3 Luna 3
obtained the first photographs of the far side of the Moon in 1959 (USSR)
Mariner 2 Mariner 2
became the The first probe to make a successful low-altitude flyby of Venus in December 1962, returning information that proved Venus to be a hot body (800 degrees Fahrenheit, now revised to 900 degrees Fahrenheit) covered by a thick cloud-like atmosphere of carbon dioxide.
Mariner 3 Mariner 3
Lifted off on November 5, 1964, and disappeared after entering interplanetary space when the protective covering failed to eject. Unable to absorb solar energy with its solar panels, the probe was also disabled shortly afterward when its batteries ran out, and it still orbits the sun to this day. It was originally launched for a flyby of Mars with Mariner 4.
Mariner 4 Mariner 4
Mariner 3's sister rover, which reached Mars in 1965, took 22 close-up photographs of the surface of Mars on its way by. The rover discovered a cratered world with a much thinner atmosphere than expected. The scientists concluded that Mars is a "dead" planet, both geologically and biologically.
Mariner 9
Mariner 9, the sister probe to the failed Mariner 8, became the first vehicle to orbit Mars in 1971, and returned the first big star of information about the Red Planet, including giant volcanoes on the surface of the planet, the Grand Canyon system, and evidence that water once flowed on the planet. The rover also took several close-up photos of Mars' two small moons, Phobos and Deimos.
Apollo Apollo
6 man-made lunar landings and retrieved lunar samples in 1969-72.
Luna 16 Luna 16
Automated retrieval of lunar samples back to Earth in 1970 (USSR)
Pioneer 10 and Pioneer 11 Pioneer 10 and 11
Pioneer 10 became the first vehicle to fly by Jupiter in 1973, followed by Pioneer 11 in 1974. Then, one after the other, they became the first probes to study Saturn in 1979. The Pioneers were also used to test survival rates through the asteroid belt with Jupiter's giant magnetic field. The truth seems to be that the asteroid belt was a real cakewalk, but they were nearly blown apart by ions in Jupiter's magnetic field. This intelligence made the situation for the later Voyager program very grim.
Pioneer 11's RTG power system was damaged, and its last contact with Earth was in November 1995. Pioneer 10 was still in good working order (but was getting close), but routine tracking of it was no longer possible due to a reduced financial budget. The last data was taken from it on 3/31/1997. They will be the first vehicles to enter interstellar space.
(The Pioneer program was officially terminated on March 31, 1997, although the U.S. side continues to contact it from time to time. -translation)
When it both leaves the solar system, it will eject a 6*9-inch gold plaque with it to the main frame of the vehicle.
Mariner 10 Mariner 10
reached Mercury in 1974 with the gravitational assistance of Venus. The probe was the first to send back close-up photographs of Venus' atmosphere in ultraviolet light, revealing many details of the cloudy cover that had not been seen before, and discovering that the entire cloud system circled the planet every four Earth days. Mariner 10 made three flybys of Mercury between 1974 and 75 before running out of energy. The flights revealed Mercury to be a world with a dense surface of craters, with a much greater mass than originally estimated, and it appears to have an iron core that occupies 75% of its total mass.
Venera 7
became the first probe to return data from the surface of another planet (Venus) in 1970.
Venera 9
In 1975, made a soft landing on Venus, sending back images of the surface (Soviet Union). Was the first vehicle to land on another planet.
Pioneer Venus
Orbital vehicle with four atmospheric probes; produced the first high-resolution map of the surface of Venus in 1978.
Viking 1 Viking 1
Launched on August 20, 1975 from Cape Canberra, Florida, on a TITAN 3E-CENTAUR D1 rocket. The rover entered orbit around Mars on June 19, 1976, and the landing gear touched down successfully on July 20, 1976, on the slopes of the Chryse Plain. It immediately went into a pre-programmed search for Martian microbes (it is still debated whether life exists on Mars) and sent back incredible full-color images of the perimeter. Scientists learned that the Martian sky was a slightly peachy pink color, not the dark blue they had originally thought (the sky is pink because red dust particles in the thin atmosphere reflect the sun's rays). The lander touched down on a patch of red sand, with large round boulders stretching out in all directions, giving it the farthest possible range of illumination.
Viking 2 Viking 2
Launched on September 9, 1975, Viking 2 entered Martian orbit on August 7, 1976, and touched down on September 3, 1976, in the Utopian Plains. Completing the same mission as its sister rovers, unexpectedly, the proper functioning of the geophone allowed it to record a Martian earthquake.
Pirate Lander 1 made its last data transmission on Nov. 11, 1982, and JPL controllers were unable to regain contact with it for 6 1/2 months. The full mission ended on 5/21/1983.
Interesting note: Viking 1's lander was named the Thomas A. Mutch Memorial Station in honor of the late leader of the lander's imaging research team. The National Museum of Gas and Space in Washington, D.C., is entrusted with the station until a human expedition meets it.
Voyager 1 Voyager 1
Voyager 1 (pictured at the top of the page) lifted off on September 5, 1977, and made flybys of Jupiter on March 5, 1979, and Saturn on November 13, 1980, respectively. Voyager 2 lifted off on August 20, 1977 (before 1) and made flybys of Jupiter on August 7, 1979, Saturn on August 26, 1981, Uranus on January 24, 1986, and Neptune on August 8, 1989. The outer planets are in a slingshot shape every 189 years, and Voyager 2 took full advantage of this. Voyager 1 could have done the same in principle, but JPL flew directly toward Pluto in order to get it on its way to approach Titan.
Between the two probe campaigns, our knowledge of the four giant planets and their moons expanded dramatically. Voyagers 1 and 2 discovered Jupiter's atmospheric dynamics, lightning, and auroras, as well as three new moons. 2 of the biggest surprises were that Jupiter has a halo, and that Io has active sulfur volcanoes, which have had a significant effect in the Jupiter magnetosphere.
When the two probes reached Saturn, they found more than 1,000 small rings and seven moons, including the expected presence of the Shepherd moon, which ensures the stability of the ring structure. The climate is fairly stable compared to Jupiter's: the grand jet stream has few bifurcations (a 33-year-old white dot/circular band was found), Titan's atmosphere is smoky and Titan's appearance is surprising: a violent planetary collision has left it with the appearance of a dead star. The big surprise is the strange appearance of the halo: spikes, bands, spokes, unexpected and unexplained.
Voyager 2 Voyager 2
Thanks to the efforts of heroic engineers and programmers, it was able to continue its mission to Uranus and Neptune. Uranus has a monochromatic appearance, and oddly enough, its magnetic field axis is also highly skewed from its already highly skewed rotation axis, giving it a strange magnetosphere. Icy straits were found on Triton and Triton is a patchwork of strange terrain. Ten moons and more than one halo were found.
Compared to Uranus, Neptune has a very active climate with a variety of cloud shapes. The halo arcs on one halo became a single bright patch. Six other moons with two halos were also found. Neptune's magnetic field axis is also very tilted. Triton's appearance has the appearance of a magnifying glass at an angle, and appears to have quite a few geysers. (Imagine what the liquid looks like under 38 open)
If no unanticipated failures occur, we will be able to stay in contact with them until 2030. Both vehicles have tons of hydrazine fuel. Voyager 1's propellant will last until 2040 and 2's until 2034. The limiting factor, on the other hand, is the RTG (Radioisotope Thermoelectric Generator). The UVS (Ultraviolet Spectrometer) instrument will run out of power by 2000. By 2010, the remaining power makes it impossible for all field and particle instruments to work simultaneously. At this point, an energy ****sharing scheme will be implemented to rotate some of the field and particle instruments with others. The vehicle can continue to operate in this state for about 10 years. At the end of the day, there may be too little energy to properly sustain the vehicle.
Vega
The international program VENUS-HALLEY, launched in 1984 with an orbiter and a lander, made a flight close to Halley's Comet.
Phobos
Two vehicles launched by the Soviet Union in 1988. One failed without a trace, and only a handful of images were sent back before the second failed.
Giotto
Giotto was launched by ESA's Ariane-1 on July 2, 1985, and reached the nucleus of Halley's Comet on March 13, 1986, at a distance of only 540 kilometers (with an error of 40 kilometers up or down). The vehicle, with 10 instruments, including a multicolor camera, returned a little data, but was soon shut down as it approached its destination and the connection was temporarily lost. The vehicle was severely damaged due to dust impacts at high speeds and was declared in hibernation shortly after entering the desired position and fixing.
Giotto was reactivated in April 1990; three instruments were still operational, four were partially destroyed but inoperable, and the rest, including the camera, were completely unusable.
Giotto encountered Earth on July 2, 1990, and was re-commissioned on July 10, 1992, bound for Comet Grigg-Skjellerup.
Clementine Clemente
The Ballistic Defense Organization's (SDIO's predecessor) joint mission program with NASA conducted a flight test of a Lawrence Livermore-developed sensor for BMDO. The vehicle was built by the Naval Investigative Laboratory and lifted off on January 25, 1994 for a 2-month 425 kt to 2,950 kt revolution over the Moon with a mapping mission. The vehicle had instruments such as UV and mid-IR mappers, and included a lidar mapper to obtain mid-latitude elevation data for the moon.Earlier in May, scientists intended to fly the vehicle out of lunar orbit to fly past asteroid 1620 Geographos, but a failure prevented the attempt.
Ground controllers regained control of the vehicle, and its future exploration missions are still under consideration.
Mars Observer Mars Observer
The Mars Orbiter, with a camera with a resolution of 1.5 m/point, was successfully launched on September 25, 1992 by the Titan III/TOS booster. As it was preparing to enter Mars orbit on August 21, 1993, contact was lost. The vehicle mission was near-canceled (after-the-fact analysis). Mars Global Surveyor, a replacement mission, lifted off in November 1996, having accomplished most of the science that MO was supposed to accomplish.
Magellan
Launched in May 1989, it mapped 98% of the surface of Venus to a resolution of 300 meters, and mapped 95% of the planet's gravity field. It recently underwent an 80-day aerobraking program to reduce its rotational altitude and slow its rotation. It has completed radar mapping and gravity data collection. In the fall of 1994, before its radioisotope thermoelectric generator reached the end of its expected life, it was intentionally sent to Venus' atmosphere for further aerobraking studies, saving most of the fuel for any future ones.
(For more information, one web page and another from JPL; status report from NSSDC)
Mars 96 Mars 96
A large orbital vehicle containing several landers, originally known as Mars 94. on November 17, 1996 the launch failed. (The original 96 was notable for a while, until the Mars 98 program was declared canceled shortly thereafter.) (More information from MSSS and from IKI (Russia))
Ongoing Missions
Voyagers 1 and 2 Voyagers 1 and 2
Could continue to operate under maneuvers for more than 15 years, during which time they traveled through space until they flew out of the solar system. It is widely believed that the Voyagers will be able to work until 2015 before the radioisotope thermoelectric generator fails. Their flight path is evidence that there are no planets beyond Pluto. Their next scientific discovery lies in finding the exact location of the edge of the Sun's atmosphere. Low-frequency emission phenomena at the edge of the sun's atmosphere can be used to help the travelers pinpoint its location.
The travelers have used their ultraviolet spectrometers to map the solar atmospheric limb and to study the interstellar winds it receives. Cosmic ray detectors monitor the energy spectrum of cosmic rays sent from outside the sun's atmosphere.
Voyager 1 has surpassed the Pioneer 10 vehicle and is the farthest away from Earth of any current man-made object.
Galileo Galileo
Jupiter's orbiter and atmospheric probe, now in orbit around Jupiter. It will make further explorations of Jupiter's moons. It has now entered Jupiter's atmosphere and will provide us with direct data about the giant red gas planet.
Galileo has already sent back disassembled photos of two asteroids, 951 Gaspra and 243 Ida, on its way to Jupiter, and it has also sent back photos of comet Sumyklevi 9, which impacted Jupiter, from its unique viewpoint.
Efforts to deploy a high-gain antenna (HGA) were abandoned; low-yield antennas can transmit only about 10 bits of data per second, and JPL originally prepared a backup plan using an enhanced receiving antenna and high-compression-rate data (JPEG-like picture compression, an instrumented method of near-lossless compression) in the Deep Space Network spacecraft. lossless compression). Due to the low speed of the low-yield antenna, Galileo was able to accomplish only 70% of its original science observations. It also suffered from the strong effects of Jupiter's climate.
Galileo Schedule (UTC time)
----------------
10/18/89 - Launch from Shuttle
02/09/90 - Flyby of Venus
10/**/90 - Venus Data Return
12/08/90 - First Flight Over the Earth
05/01/91 - Failure to open high-yield antenna
07/91 - 06/92 - First flyby of the asteroid belt
10/29/91 - Pass of asteroid Gaspra
12/08/92 - Second flyby of the Earth
05/93 - 11/93 - Second flyby of the Asteroid Belt
08/28/93 - Flyby of Asteroid Ida
07/13/95 - Probe Flyby
07/20/95 - Orbiter Deviates from Expectations
12/07/95 - Meeting with Jupiter
06/27/96 06:30 - Ganymede-1
09/06/96 19:01 - Ganymede-2
11/04/96 13:30 - Callisto-3
11/06/96 18:42 - Europa-3A (unanticipated meeting, in same rotational orbit as Callisto, separated from Callisto by 32000 kilometers)
12/19/96 06:56 - Europa-4
01/20/97 01:13 - Europa-5A (flew by 27,400 kilometers away)
02/20/97 17:03 - Europa-6
04/04/97 06:00 - Europa-7A (unanticipated meeting, 23,200 km away in Ganymede-7 rotational orbit)
04/05/97 07:11 - Ganymede-7
05/06/97 12:12 - Callisto-8A (unanticipated meeting, 33,500 km away in Ganymede-8 orbit)
05/07/97 15:57 - Ganymede-8
06/25/97 13:48 - Callisto-9
06/26/97 17:20 - Ganymede-9A (unanticipated meeting, 80,000 km away on Callisto-9 orbit)
06/26/97 17:20 - Ganymede-9A (unanticipated meeting, 80,000 km away on Callisto-9 orbit)
05/06/97 12:12 - Callisto-8A (non-anticipated meeting, 33,500 km from on)
09/17/97 00:21 - Callisto-10
11/06/97 21:47 - Europa-11 (more details)
Galileo's expanded mission has been passed, and if it goes well, it will concentrate on Io for another two years.
(Education and Public Outreach (with pictures!) ; Galileo Home Page; Galileo Probe Home Page and more info from JPL; newsletter; web page; NSSDC page; preliminary Galileo Probe results from JPL and ARC and LANL)
Hubble Space Telescope Hubble Astronomical Telescope
Launched over the sky in April 1990 and in December 1993 underwent tune-up repairs. Hubble was able to provide photos and spectra for a long time. This has become an important alternative factor in planetary exploration for obtaining higher resolution data. Recent data from Hubble, for example, show that Mars is colder and drier now than it was during the Viking mission; Hubble telescope data on Neptune show that its atmospheric landscape is changing rapidly.
It was named in honor of American astronomer Edward Harbaugh.
More information and photos of Hubble are available at the Space Telescope Science Institute. The latest images of Hubble are often published with regularity. (This is a major history of the Hubble Space Telescope program. JPL has more information on Hubble.)
Ulysses
Now investigating and studying the polar regions of the Sun (ESA/NASA) Ulysses was launched in October 1990 by the spacecraft Discovery. In February 1992, it was lifted out of the ecliptic plane by the gravitational pull of Jupiter. It has now completed its primary mission of observing the poles of the Sun. Its mission has been extended to another range, that of observing the Sun's poles during the period of maximum sunspot activity. Its aphelion is 5.2 astronomical units, and surprisingly, its perihelion is about 1.5 astronomical units - that's right, a craft studying the Sun is generally farther from the Sun than the Earth is from the Sun. Expect it to provide better data useful for studying the Sun's magnetic field and solar wind.
Wind
After its launch on November 1, 1994, NASA's Wind satellite will occupy a vantage point between the Sun and the Earth, giving scientists an excellent opportunity to study what is thought to be a huge flow of energy and momentum in the solar wind.
The primary goal of the mission is to measure the mass, momentum and energy of the solar wind that is somehow transferred to Earth's outer space. Although much has been learned from previous space programs about the nature of this tremendous transfer, a great deal of detailed information from key regions of Earth's outer space is necessary before scientists can understand the way planetary atmospheres respond to changes in the solar wind.
The launch is also the first time a Russian instrument has been mounted in a U.S. space vehicle. It is the Konus Gamma ray spectrometer, supplied by the Russian Ioffe Society. It is one of two instruments on Wind. It is studying the impact of cosmic gamma rays, not the solar wind. There is also a French instrument on board the ship.
At first, the satellite will orbit the Earth in a figure-8 with the help of the moon's gravitational field. Its farthest point away from Earth will be 990,000 miles (1,600,000 kilometers), and its closest point will be at least 18,000 miles (29,000 kilometers).
The mission pull down is that the Wind spacecraft will be inserted into a special halo ring of the solar wind against the current from Earth, staying at a specific distance that allows Wind to be maintained at the sun and Earth. (That's about 93,000 to 105,000 miles, or 1,500,000 to 1,690,000 kilometers, from Earth.)
NEAR
The Near-Earth Asteroid Rendezvous (NEAR) program is guaranteed to answer fundamental questions about the nature of near-Earth objects such as asteroids between the orbits of Jupiter and Mars, and comets.
Launched on Feb. 17, 1996, on a Delta 2 rocket, the NEAR space vehicle should arrive in early January 1999 in orbit around asteroid 433 Eros. It will then observe the rocky body for at least a year at an altitude of nearly 15 miles (24 kilometers).Eros is one of the largest and best-observed of the asteroids moving in orbit across the path of the Earth. These asteroids are closely related to the countless "main belt" asteroids that orbit the Sun in a giant circular orbit between Mars and Jupiter.
Mars Surveyor Program
Mars Global Surveyor is the first mission in a new ten-year program of remote exploration of Mars. It is called the Mars Exploration Program. Every 26 months a series of active orbital orbiters and landers will be launched elevated as Mars orbits to a straight line with Earth at this point. The program is affordable, costing about $100 million per year. The public is assured of up-to-date and close-up images of the Martian globe. With the development of space technology at the leading edge, higher scientific value can be obtained.
The Mars Global Surveyor will be a space vehicle that will orbit the poles of Mars. It is designed to provide global maps of surface topography, distribution of ores and detection of global climate.
On November 7, 1996, it was launched on a Delta II disposable rocket from Cape Canaveral, Fla. The spaceflight was in a ecliptic orbit around Mars. During that year, thruster ignition and aerobraking techniques would be used to reach a predefined, nearly circular orbit over the polar cap of Mars. Aerobraking, a technique pioneered by the Magellan program, uses atmospheric drag to slow a spacecraft to its final, intended orbit. This will provide a way to reduce the amount of fuel needed to reach a low operational orbit of Mars. The booked operation is expected to begin in March 1999.
The vehicle will orbit Mars every two hours, maintaining a "sun-synchronized" orbit, which will make the sun's angle to the horizontal a constant value in every picture, allowing the shadows cast by the midday sun to make the surface topography stand out. The spacecraft will carry a portion of the Mars Observer Instrumentation Box, which will be used to acquire data from Mars over an entire Martian year. A Martian year is equivalent to almost two Earth years. The spacecraft will serve as a data relay and low-altitude probe for U.S. and international landers for the next three years.
Pathfinder
Mars Pathfinder (formerly known as Mars Environmental Surveyor or MESUR or Pathfinder) is the second NASA low-cost planetary discovery mission. The mission consisted of a stationary landing module and a surface rover like Traveler. The original purpose of the mission was to demonstrate the feasibility of landing and exploring on the surface of Mars at low cost. This goal will be met through tests of the rover and lander, lander-to-Earth information, and tests of graphics equipment and sensors.
Its scientific objectives include access to atmospheric science, far and near surface imagery. It carries the goal of characterizing the Martian environment for further exploration. Instead of entering orbit around the planet, the vehicle will enter the Martian atmosphere and land on Mars. It will descend with parachute gear, rockets and air bags, and take atmospheric measurements. Before landing, the spacecraft will be surrounded by three triangular panels (petals). They unfold to the ground after landing.
Mars Pathfinder was launched on December 4, 1996, and successfully landed on Mars on July 4, 1997, after a successful launch.
Cassini Cassini
Saturn's rotating orbiter and Titan's atmospheric probe. Cassini is a joint NASA/ESA project. The project was designed to complete the exploration of the Saturn system with its Cassini Saturn Orbiter and Huygens Titan probe. Cassini was launched on October 15, 1997 aboard IV/Centaur. Cassini will arrive at Saturn on July 1, 2004, after two Venus gravitational accelerations and one each from Earth and Jupiter (a "VVEJGA" trajectory (Venus Venus Earth Jupiter Gravity Acceleration)).
Lunar Prospector Lunar Prospector
Lunar Prospector, was the first NASA program to come to the Moon in nearly 30 years. It was launched on June 6, 1998, and in one month it will begin to answer long-standing questions about the Moon and its resources, structure, and origin. (Welcome to the Moon, Lunar Prospector Home Page); More information from NSSDC
Future Missions
Mars Surveyor '98 Mars Prospector 98
Mars Prospector 98 is the next generation of vehicles to be sent to Mars. It is composed of an orbiter launched on December 10, 1998 and a lander launched in June 1999. Building on the information gained from the Mars Global Surveyor and Mars Pathfinder missions, the Mars 98 mission will continue to grow in insight, with the science theme for the 1998 Prospector program being "Volatiles and Climate History."
On Sept. 23, 1999, the Mars Explorer 98 orbiter will reach Mars, and on Dec. 3, 1999, the lander will touch down.
The images obtained during the lander's descent to the surface will determine the relationship between the geology and physics of the landing site. The Atmospheric Lidar Experimenter will determine the dust content of the Martian atmosphere above the landing site.
Stardust
Planned for launch in February 1999, Stardust will fly very close to the comet and, for the first time ever, bring back material from the comet's tail to Earth for analysis by scientists worldwide. The plan is to fly by comet Wild-2 in 2004 and return to Earth in 2006.
Europa Orbiter The Europa Orbiter
A mission to send a vehicle to Europa Io is beginning to be scheduled as part of NASA's Ice and Fire Preprojects. It's designed to measure the thickness of the surface ice and go on to discover the possible existence of hidden liquid oceans. Using an instrument called a radar sounder to send radio waves through the ice, the Io orbiter's science vehicle will be able to detect the interface between ice and water, possibly 1 kilometer below the surface. Other instruments will reveal details of the surface and internal layers. The mission will be a precursor to sending out "hydrobots," or submarines that can melt through the ice and explore the extent of the seafloor.
(home page; see Jovian Europa Ocean Exploration)
Pluto-Kuiper Express
(i.e., Pluto Direct or formerly Pluto Fast Flyby) provides a short, quick, and relatively inexpensive initial look at the hitherto unvisited planet Pluto. If licensing approval is granted beginning in 1998, it could be launched in 2001. It would require launching two space vehicles weighing less than 100 kilograms, lifting off in 2001 on Titan IV/Centaura or Proton rocket propulsion (additional solid recoil platforms may be required), and encountering Pluto and Charon Pluto in 2006 to 2008 (depending on the choice of path). Flyby speeds will be 12 to 18 kilometers per second, and data will be recorded on the probes during brief encounters and then slowly transmitted back to Earth over the next year or even later (this is due to the low energy, small antenna size, and long distances). Russia's Drop Zond probe, which examines the atmosphere, will also be included.
Scientific objectives include mapping the global geology of Pluto and Charon. Mapping the sides of each object and mapping Pluto's atmosphere (Pluto's atmosphere condenses as it moves away from the Sun, so early launches and minimized flight times are harsh for this purpose.) The 7-kilogram food setup will likely include a CCD image camera, an IR mapping spectrometer, an ultraviolet spectrometer, and a radio-science occultation experimenter.
This PFF vehicle is the product of a highly scaled-down version of the modern-specification outer-space launch pads, breaking the trend toward increasingly complex and expensive probes like Galileo and Cassini.
An article about PFF, written by the designer, appeared in the September and October 1994 issues of The Planetary Reporter, a bimonthly newsletter from the planetary research community.
How much money is to be spent on this project is uncertain.
(More from NASA; Pluto Direct Program; Pluto Direct Science)
Muses-C
The Japanese-managed mission will collect samples from an asteroid and bring them back to Earth. The innovative mission will utilize new space technology, including space electric propulsion, in order to send a spacecraft up to the 4660 Nereus asteroid and release a JPL research rover onto the asteroid's surface, which is about the size of a shoebox.The Muses-c vehicle will also ignite explosive materials inserted into the asteroid, collect samples ejected from the impact, and then bring the samples back to Earth in a container. The samples will be brought back to Earth in a container for laboratory study and analysis. This mission is expected to launch overhead in 2002.
Mercury Polar Flyby Flyby of Mercury's Pole
As a result of the renewed interest in Mercury, there are two related programs moving toward a possible Discovery module mission. Discovery is NASA's "cheaper, better, faster" solar system exploration vehicle. The total **** cost of these missions has been kept to $150 million. The vehicles for the two Mercury programs are the Probe Flyer (MPF), which flies close to Mercury's magnetic poles, and Hermes, the Mercury Orbiter.The MPF's instrumentation consists of a neutron spectrometer (for water detection) and a compound polarization radar (for rocky ice detection) and cameras (to take magnetic field and hemispherical images that Mariner 10 could not take). We believe that a spacecraft program to fly close to the object for exploration is a cheaper and more technically feasible option.The MPF is designed to make only a few encounters with Mercury at aphelion. At aphelion, a vehicle would only have to withstand the equivalent of four times the heat transfer between the Sun and the Earth. Mercury's orbit is so eccentric that it has 11 times the variation at perihelion. An orbiter would have to withstand such conditions, which would require elaborate (and expensive) thermal and cold protection systems. hermes is the result of JPL and TRW ****ing together. If this gets approved, it will be launched into space in 1999.
(All missions not otherwise noted are owned by NASA)