Is it possible to land space probes on the outer planets

They were sent to Mars to look for evidence of water. Each rover carried scientific instruments to help scientists explore the planet from Earth. The Earth-bound scientists tell the rovers where to go and what to examine.

As the rovers move across the surface, they examine soil and rocks. This information is sent back to Earth. The rovers were built to last approximately 90 days. Spirit went silent on March 22, Opportunity is still working as of November 1, ! And they have found lots of evidence that water was once all over the surface of Mars! The Cassini probe to Saturn was launched on October 15, It is the biggest and most expensive probe to ever visit another planet.

The Cassini spacecraft went into orbit around Saturn in July It has studied the planet, its ring system, and many of its moons for more than ten years!

Then ask: What is an example of a tool we use on Earth to provide friction against the pull of gravity and slow the speed of a falling person or object? Students should think of parachutes, which provide resistance or opposing force. If they need prompting, ask them to think about skydivers or the space shuttle when it lands.

Explain to students that space probes may also use parachutes to land safely on a planet. Have students advise you on how to adjust the diameter, band width, and material thickness until the parachute successfully passes a test of its volume, drag, strength, and stability.

Have students design and build lander models. Project the illustration Space Probe Lander for students to refer to. Divide students into small groups. In one space in the classroom, set out all possible materials students can choose from to build their landers. Give each group time to choose the following:. Encourage students to consider not just the material of each part, but size as well. Allow groups time to discuss, design, and draw their lander models.

Then have them build the separate parts. Once students have built the parachute and protected lander container, have students secure the strings of the parachute to the lander container. If any groups decide to use a rubber band, ask them to make sure it fits securely around the egg, but not so tightly that it cuts into the egg. Select and set up the drop site. As a class, select a drop site that will allow students to drop their landers from a defined height.

A stairwell is ideal, if available. If not, you can use a stepladder or select another area that will allow for different drop heights. Make sure you take student safety into consideration when choosing the drop site.

Create a landing area by clearing the space and covering it with a tarp or large sheet of plastic. Define a target area for groups using that criteria. Have small groups complete five tests each. Give students time and opportunity to test and gather data. Provide each group with the appropriate measurement device to collect data, based on their chosen criteria for success.

For example, if they decide on highest drop or closest to the target, students will need a meter stick. For longest air time, students will need a stop watch. Make sure all groups have at least five eggs to use for redesign and testing. Have students record data on their worksheets for measurements, observations, and design changes for each of five tests. Have groups compare and analyze data. Have groups compare and contrast their data. Tell students that scientists use vacuum chambers and reduced gravity flights to test possible results.

Ask each student to write a paragraph summarizing their group's engineering process and results. Then have students identify possible improvements to the design, and draw and label their lander with its proposed improvements. Have each small group repeat the testing process using different criteria for success than during original testing. Ask them to reflect on any differences in results. You will either need access to a stairwell or another way to provide students with a test site that allows them to drop their landers from varied heights, such as open space for a stepladder in your classroom.

Note that testing may be messy if eggs break. Be prepared to clean up after the activity. When scientists and engineers want to send a probe to land on another planet, they first decide where to land and the method they will use to get the probe there.

The largest craters have apparently been erased by the flow of the icy crust over geologic time. Almost no topographic relief is apparent in the ghost remnants of the immense impact basins, identifiable only by their light color and the surrounding subdued rings of concentric ridges. A faint, dusty ring of material was found around Jupiter. Its outer edge is , kilometers 80, miles from the center of the planet, and it extends inward about 30, kilometers 18, miles.

Two new, small satellites, Adrastea and Metis, were found orbiting just outside the ring. A third new satellite, Thebe, was discovered between the orbits of Amalthea and Io. Jupiter's rings and moons exist within an intense radiation belt of electrons and ions trapped in the planet's magnetic field. These particles and fields comprise the jovian magnetosphere, or magnetic environment, which extends three to seven million kilometers toward the Sun, and stretches in a windsock shape at least as far as Saturn's orbit -- a distance of million kilometers million miles.

As the magnetosphere rotates with Jupiter, it sweeps past Io and strips away about 1, kilograms one ton of material per second. The material forms a torus, a doughnut-shaped cloud of ions that glow in the ultraviolet. Some of the torus's heavy ions migrate outward, and their pressure inflates the Jovian magnetosphere, while the more energetic sulfur and oxygen ions fall along the magnetic field into the planet's atmosphere, resulting in auroras. Io acts as an electrical generator as it moves through Jupiter's magnetic field, developing , volts across its diameter and generating an electric current of 3 million amperes that flows along the magnetic field to the planet's ionosphere.

Voyager 1 flew within 64, kilometers 40, miles of the cloud tops, while Voyager 2 came within 41, kilometers 26, miles. Saturn is the second largest planet in the solar system.

It takes Saturn is known to have at least 17 moons and a complex ring system. Like Jupiter, Saturn is mostly hydrogen and helium. Its hazy yellow hue was found to be marked by broad atmospheric banding similar to but much fainter than that found on Jupiter. Close scrutiny by Voyager's imaging systems revealed long-lived ovals and other atmospheric features generally smaller than those on Jupiter. Perhaps the greatest surprises and the most puzzles were found by the Voyagers in Saturn's rings.

It is thought that the rings formed from larger moons that were shattered by impacts of comets and meteoroids. The resulting dust and boulder- to house-size particles have accumulated in a broad plane around the planet varying in density. The irregular shapes of Saturn's eight smallest moons indicates that they too are fragments of larger bodies.

Unexpected structure such as kinks and spokes were found in addition to thin rings and broad, diffuse rings not observed from Earth. Much of the elaborate structure of some of the rings is due to the gravitational effects of nearby satellites. This phenomenon is most obviously demonstrated by the relationship between the F-ring and two small moons that "shepherd" the ring material.

The variation in the separation of the moons from the ring may the ring's kinked appearance. Shepherding moons were also found by Voyager 2 at Uranus.

Radial, spoke-like features in the broad B-ring were found by the Voyagers. The features are believed to be composed of fine, dust-size particles. The spokes were observed to form and dissipate in time-lapse images taken by the Voyagers.

While electrostatic charging may create spokes by levitating dust particles above the ring, the exact cause of the formation of the spokes is not well understood. Winds blow at extremely high speeds on Saturn -- up to 1, kilometers per hour 1, miles per hour. Their primarily easterly direction indicates that the winds are not confined to the top cloud layer but must extend at least 2, kilometers 1, miles downward into the atmosphere.

The characteristic temperature of the atmosphere is 95 kelvins. Saturn holds a wide assortment of satellites in its orbit, ranging from Phoebe, a small moon that travels in a retrograde orbit and is probably a captured asteroid, to Titan, the planet-sized moon with a thick nitrogen-methane atmosphere.

Titan's surface temperature and pressure are 94 kelvins Fahrenheit and 1. Photochemistry converts some atmospheric methane to other organic molecules, such as ethane, that is thought to accumulate in lakes or oceans. Other more complex hydrocarbons form the haze particles that eventually fall to the surface, coating it with a thick layer of organic matter.

The chemistry in Titan's atmosphere may strongly resemble that which occurred on Earth before life evolved. The most active surface of any moon seen in the Saturn system was that of Enceladus. The bright surface of this moon, marked by faults and valleys, showed evidence of tectonically induced change. Voyager 1 found the moon Mimas scarred with a crater so huge that the impact that caused it nearly broke the satellite apart.

Saturn's magnetic field is smaller than Jupiter's, extending only one or two million kilometers. The axis of the field is almost perfectly aligned with the rotation axis of the planet. URANUS In its first solo planetary flyby, Voyager 2 made its closest approach to Uranus on January 24, , coming within 81, kilometers 50, miles of the planet's cloud tops. Uranus is the third largest planet in the solar system. It orbits the Sun at a distance of about 2.

The length of a day on Uranus as measured by Voyager 2 is 17 hours, 14 minutes. Uranus is distinguished by the fact that it is tipped on its side. Its unusual position is thought to be the result of a collision with a planet-sized body early in the solar system's history. Given its odd orientation, with its polar regions exposed to sunlight or darkness for long periods, scientists were not sure what to expect at Uranus.

Voyager 2 found that one of the most striking influences of this sideways position is its effect on the tail of the magnetic field, which is itself tilted 60 degrees from the planet's axis of rotation. The magnetotail was shown to be twisted by the planet's rotation into a long corkscrew shape behind the planet. The presence of a magnetic field at Uranus was not known until Voyager's arrival.

The intensity of the field is roughly comparable to that of Earth's, though it varies much more from point to point because of its large offset from the center of Uranus. The peculiar orientation of the magnetic field suggests that the field is generated at an intermediate depth in the interior where the pressure is high enough for water to become electrically conducting.

Radiation belts at Uranus were found to be of an intensity similar to those at Saturn. The intensity of radiation within the belts is such that irradiation would quickly darken within , years any methane trapped in the icy surfaces of the inner moons and ring particles.

This may have contributed to the darkened surfaces of the moons and ring particles, which are almost uniformly gray in color. A high layer of haze was detected around the sunlit pole, which also was found to radiate large amounts of ultraviolet light, a phenomenon dubbed "dayglow. Surprisingly, the illuminated and dark poles, and most of the planet, show nearly the same temperature at the cloud tops.

Voyager found 10 new moons, bringing the total number to