With Magellan safely in orbit around Venus today, exuberant NASA engineers started preparing the spacecraft for a mapping mission meant to reveal what forces shaped the landscape of the hellishly hot planet. ``We think we'll see lots of rocky surfaces, hills and dales and volcanoes,'' said Bill Johnson, chief engineer for Magellan's radar imaging system. Geologists hope the $744 million exploration will reveal ``the way the planet works internally, the way mountains are built and the way volcanoes work,'' said Steve Saunders, chief Magellan scientist at NASA's Jet Propulsion Laboratory. The mapping is set to start next month. On Friday, Magellan plunged over the north pole of Venus, fired its braking rocket and dropped into an elliptical orbit that ranges from about 171 miles to 5,054 miles above the planet's surface. ``We made it!'' said Carolynn Young, a Magellan project team member. ``I had goose bumps from head to toe. It's wonderful.'' The spacecraft successfully jettisoned the retrorocket Friday night, laboratory spokesman Bob MacMillin said. He said engineers' plans for today included monitoring Magellan's performance and collecting precise information on its orbit _ details needed for successful mapping. Magellan's arrival at Venus broke a string of bad luck for NASA. Hydrogen gas leaks have grounded the shuttle fleet temporarily and a mirror focusing flaw severely impaired the $1.5 billion Hubble Space Telescope. Magellan is equipped with radar designed to peer through the thick Venusian clouds and unveil the landscape of the second planet from the sun. On Sept. 1, it will start mapping by bouncing radar waves off Venus and capturing the echoes. NASA said the radar should be able to yield pictures and maps of about 90 percent of Venus at a level of detail 10 times better than in images produced by two Soviet Venera spacecraft that were launched in 1983. It should be able to detect features as small as about two football fields. ``It's like going to the Grand Canyon instead of having someone tell you about it,'' mission analyst Rob Lock said. Magellan project manager Tony Spear said some worthwhile pictures of Venus' surface may be produced by radar tests that start next Thursday, but ``it is most likely in September ... that we will get images of sufficient quality.'' Magellan was launched from the shuttle Atlantis on May 4, 1989, starting a roundabout 948-million-mile journey to Venus. It met the planet at a distance of 144 million miles from Earth. Venus is Earth's nearest neighbor other than the moon, and is similar to Earth in size, mass, density and position. Magellan may reveal similarities and differences between the two planets, including whether any of Venus' volcanoes are active and whether its surface features are formed by large-scale movements of gigantic plates of rocky crust. It also will look for signs that the bone-dry planet may have had oceans before a runaway ``greenhouse effect'' raised its surface temperature to 900 degrees Fahrenheit. Saunders said Magellan has no ability to determine what caused global warming on Venus, but may find clues to when it started. Lennard Fisk, NASA's associate administrator for space science, called Magellan's arrival at Venus ``the beginning of one of the most exciting eras of planetary exploration'' _ a period that includes upcoming missions to Jupiter, Mars, Saturn, asteroids and comets. Magellan was the first U.S. planetary spacecraft launched since Pioneers 12 and 13 were sent to Venus in 1978, and also the first launched from a shuttle. Magellan, named for 16th century global circumnavigator Ferdinand Magellan, is 21 feet long and 15 feet wide. After firing the heavy fuel-filled braking rocket, its 3.7-ton weight dropped to less than 1.5 tons, Spear said.
