Number 105 (Story #5), December 4, 1992 by Phillip F. Schewe and Ben Stein SPACECRAFT UPDATE: The Mars Observer craft was launched on 25 September 1992 and will reach Mars in August 1993. It will assume a polar orbit and begin mapping the planet's surface. The Pioneer Venus craft ran out of fuel and fell into Venus's clouds on 8 October 1992 after having served for 14 years, far longer than the originally-planned 243 days. Meanwhile, Voyager 1 is now 50 astronomical units (4.6 billion miles) away from the Sun and traveling at an angle of 35 degrees to the ecliptic plane. Astronomers hope that both Voyager 1 and Voyager 2 will reach the heliopause (the start of interstellar space) at an estimated distance of 60-90 AU. Finally, the Magellan spacecraft is now performing its fourth cycle of mappings of the Venusian surface. Project scientists would like to extend the mission and send the craft into a lower orbit, the better to probe the planet's interior by searching for gravity anomalies. (Astronomy, Jan. 1993.)