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2	45 Years of Space Exploration From Explorer 1 to Cassini
3	Explorer 1 NASA’s first orbital mission. Launched on January 31, 1958. First to discover the Van Allen Belts. Marked the beginning of our scientific investigation of space through direct, in-situ measurements.
4	The Architects of Explorer 1
5	The Van Allen Belts
6	The Mariner Missions Mariner 2 (pictured) was launched on August 27, 1962, and bound for Venus. Mariner 4 was launched on Nov. 28, 1964 bound for Mars. These were the first two successful probes in the Mariner series. The series culminated in Mariner 10 which investigated Venus and Mercury.
7	Mariner 2 Mariner 2 was the world’s first successful interplanetary probe. Reaching Venus in December of 1962, measured the surface temperature of Venus and discovered that Venus lacks a magnetic field and radiation belts.
8	Mariner 4 Mariner 4 was the first probe to image the Martian surface. (first image pictured right)
9	Ranger and Surveyor Missions Although Pioneer 4 was our first probe to reach the Moon in 1959, its imager failed to activate. Ranger 7, launched on July 28, 1964, was our first completely successful mission to the Moon. The Surveyor missions were designed to land safely on the lunar surface. Surveyor 1 arrived safely and was the first craft to achieve a soft landing.
10	Pioneer 10 and 11 Pioneer 10 and 11, launched on March 2, 1972 and April 5, 1973, were the first probes to be sent beyond the asteroid belt. The Pioneer missions provided critical information about the Jovian radiation belts. As result of the Pioneer findings, the two Voyager spacecraft were hastily redesigned to survive the intense radiation around Jupiter.
11	IMP-8 (IMP-J) Launched on October 28, 1973, IMP-8 is now the longest lasting NASA mission ever. IMP-8 is still in Earth orbit monitoring cosmic rays, the solar wind, and the Earth’s magnetosphere. IMP-8 data are used now to analyze the behavior of cosmic rays as a function of heliolatitude, distance, and time.
12	IMP-8 Dataset Overview
13	Viking I and II The two Viking missions, launched on August 20, 1975 and September 9, 1975, were NASA’s first spacecraft to land on the surface of another planet. (The USSR landed Venera 7 on Venus on October 22,1975.) The orbiters provided a nearly full global map of Mars. The landers provided our first weather data from another planet, and analyzed the Martian soil finding significant amounts of iron oxide. (hence the rust red color of Mars)
14	The Martian Desert from Viking I
15	Voyagers I and II: The Grand Tour The two Voyager probes, launched in August 22 (V2) and September 5, 1977 (V1), are the most ambitious missions NASA has ever undertaken. Voyager 1 visited Jupiter and Saturn before being sent out of the ecliptic plane during its Titan flyby. Voyager 2 is the only probe ever to have visited the two outermost gas giants, Uranus and Neptune.
16	Voyager 1 Provided stunning images of the four Galilean moons of Jupiter showing that the moons of the gas giants need not be the cold, dead, iceballs scientist expected. At Saturn, Voyager imaged Saturn’s largest moon Titan and discovered that Titan has a thick atmosphere. Voyager 1 is now at the outer edge of our solar system and will soon leave the Sun’s magnetosphere and enter interplanetary space.
17	Voyager 2 Only probe to ever visit Uranus and Neptune, and likely to be the only probe to do so in our lifetimes. First to discover Jupiter’s thin rings. First to observe volcanic activity on another body, Jupiter’s moon Io. Also discovered volcanoes and geysers of liquid nitrogen on the coldest known moon in the solar system, Triton, a moon of Neptune.
18	Magellan Magellan used radar to penetrate the opaque cloud deck and map the surface. The Magellan data were far better than any other mapping data previously taken. The results of the Magellan data made it necessary to significantly modify, or in some cases abandon, models of planetary surface modification.
19	Galileo Galileo was designed to orbit Jupiter and study the plasma environment and Jupiter’s four Galilean moons. Galileo also released a probe into Jupiter’s atmosphere to determine the composition and structure of the atmosphere. Galileo’s repeated visits to the four Galilean moons have revealed much about their structure. One of the most significant findings was the presence of a salt water ocean under the surfaces of both Europa and Ganymede.
20	Ulysses Ulysses was sent out to Jupiter on October 6, 1990. Using Jupiter’s gravitational field, Ulysses was sent into an orbit nearly perpendicular to the orbital plane of the planets. This is the only probe that is capable of viewing the regions above and below the Sun’s poles and has provided valuable data that has led to new understanding of how our Sun behaves.
21	NEAR: Near-Earth Asteroid Rendezvous NEAR was the first probe to enter an orbit around an asteroid. NEAR has approached as close as 50 km to the asteroid Eros. In addition to some fantastic photographs, NEAR is also probing the gravitational and magnetic fields of Eros and using remote techniques to determine the composition of the asteroid.
22	Eros Up Close!
23	Pathfinder and Sojourner The Pathfinder mission, launched on December 2, 1996, was the first mission to deploy a mobile rover. The Sojourner rover was able to move around and analyze nearby rocks and soil. In addition to the proving of microrover technology, the Pathfinder also demonstrated the effectiveness of economical airbags as a soft landing device.
24	Cassini Cassini was launched on October 15, 1997, and has been taking a very circuitous route to Saturn, passing Venus, Earth, and Jupiter to gain enough energy to make the trip. Cassini arrived at Saturn in July of 2004 and began studying the Saturn’s rings, moon, magnetic field, and radiation environment. The Huygens probe will detach from Cassini and descend into the atmosphere of Titan perhaps achieving a soft landing on the surface. …if the surface is solid.
25	Coming Soon! MESSENGER: Launched August of 2004 This is the first Mercury mission since Mariner 10. As opposed to Mariner, MESSENGER will be an orbiter. New Horizons: January 2006 (now in doubt) Hew Horizons is the first mission planned to visit Pluto and the Kuiper Belt. The journey will be VERY long and the vehicle will not arrive at Pluto until 2015 and will investigate various Kuiper Belt objects until 2026!