Jupiter The Galileo Mission example essay topic

The NASA Galileo mission's main objective was to study Jupiter, its moons and it magnetosphere. It planned to accomplish this via two spacecraft, an atmospheric orbiter and a probe that would be released from the orbiter upon arrival. Launched on October 18, 1989 from Cape Canaveral, the spacecraft pair reached Jupiter in December 1995. During its journey to Jupiter it was the first mission to complete a close asteroid flyby - on asteroid Gaspra - and to discover the satellite of an asteroid - Ida's satellite Dactyl - as well as make important observations about the moon. Since reaching Jupiter the Galileo mission has been a huge success, with the Galileo Orbiter even having made an extended tour - the Galileo Europe Mission (GEM) - for fourteen extra orbits. SCIENTIFIC GOALS The Galileo Orbiter and Probe had individual scientific goals.

The Probe would be sent straight into Jupiter's atmosphere to reach these goals whereas the Orbiter would make numerous orbits at various distances from Jupiter. The goals of the Galileo Probe were to - Determine the chemical composition of Jupiter's atmosphere - Discover the structure of the atmosphere to a pressure depth of at least 10 bars - Investigate the nature of cloud particles and the location and structure of cloud layers - Examine the radiative heat balance - Study the nature of Lightning activity of Jovian planets such as Jupiter - Measure the flux of energetic charged particles down to the top of the atmosphere. The objectives of the Galileo Orbiter were to: - Investigate the circulation and dynamics of the atmosphere of Jovian planets such as Jupiter. - Investigate the upper atmosphere and ionosphere; - Determine the morphology, geology, and physical state of the Jupiter's main (Galilean moons - Investigate the composition and distribution of surface minerals on the main moons - Determine the gravitational and magnetic fields and dynamic properties of the main moons - Study the atmospheres, ionospheres, and extended gas clouds of the mains moons - Study the interaction of Jupiter's magnetosphere with the main moons, and characterize the vector magnetic field and the energy spectra, composition, and angular distribution of energetic particles and plasma to a distance of 150 Rj CURRENT HEALTH AND LOCATION The Galileo Probe melted and vapour ised after collecting 58 minutes of data during its descent into Jupiter's atmosphere in December 1995. Galileo Orbiter's current location as of September 1, 2003 is 10.859 x 106 km from Jupiter with a phase of 8.4 degrees. Galileo Orbiter is in good health, having even survived Jupiter's intense radiation interfering with its electronics as it approached Io.

It is however almost out of fuel. The Galileo mission will end when the Galileo Orbiter intentionally impacts Jupiter on September 21, 2003. RESULTS OF THE MISSION The Galileo mission made many discoveries about Jupiter and its moons. Most notably: - The discovery of an intense interplanetary dust storm - The discovery of an intense new radiation belt approximately 50,000 km above Jupiter's cloud tops - Wind speeds in excess of 600 kilometers per hour were detected - Far less water was detected in Jupiter's atmosphere than estimated from earlier Voyager observations and from models of the Comet Shoemaker-Levy 9 impact - Far less lightning activity than anticipated.

However the individual lightning events are about ten times stronger on Jupiter than on Earth - The abundance of Helium in Jupiter is practically the same as its abundance in the Sun - The discovery of extensive resurfacing of Io's surface due to continuing volcanic activity since the Voyagers flew by in 1979 - Preliminary data supports the existence of magnetic fields for both Io and Ganymede - The discovery of evidence for a liquid water ocean under Europa's surface The Galileo mission also made discoveries about the Moon and the asteroids Ida and Gaspra during its flyby's of them on its way to Jupiter. It was confirmed that a huge ancient impact basin exists in the southern part of the Moon's far side. There is now also evidence of more extensive volcanism on the Moon than was previously thought. Dactyl was discovered as a satellite of the asteroid Ida.

These results have greatly improved our understanding of Jovian planets and their satellites. For the Jovian planets it was namely their atmospheric composition and behaviour and the strength and behaviour of their magnetospheres on which the Galileo mission shed further light. For the Galilean Satellites the mission revealed the make up of their surfaces and also the possible existence of magnetic fields for Io and Ganymede. These discoveries have helped scientists raise new questions and theories about Jupiter and its moon, one such being whether life might exist under Europa's icy crust.

Bibliography

The Nine Planets web National Space Science Data Centre web Jet Propulsion Laboratory web Space Projects Division web.