The multi-billion dollar Cassini mission to Saturn, dogged by controversy about its power supply, successfully launched on a nearly seven-year journey early Wednesday morning, October 15.
     The Titan 4B rocket carrying Cassini lifted off from Cape Canaveral, Florida, at 4:43am EDT (0843 UT). All systems were working well during the launch, and the spacecraft separated from its Centaur upper stage on schedule.
     The launch, which had already been delayed a week because of minor repairs to insulation on the spacecraft performed last month, was delayed by two days October 13 when mechanical and meteorological problems appeared. The launch was first delayed by about an hour when a servicing platform failed to retract on schedule a few hours before launch.
     Strong winds in the upper atmosphere along with winds blowing to the west on the ground made conditions unacceptable to launch. The strong upper winds could have blown any debris from an explosion out of the designated impact area, while surface winds could have blown toxic fumes from the rocket's fuel towards populated areas in an accident.
     In addition to the winds, problems were detected with another set of ground equipment as well as a software glitch in one of Cassini's computers. All worked together to delay the launch by 48 hours.
     Cassini, whose use of plutonium-powered RTGs to supply electrical power to the spacecraft has made the mission controversial, got past one final legal hurdle in the days before launch. A federal judge in Honolulu refused to grant on October 11 an emergency injunction filed by anti-nuclear activists.
     The injunction request, filed by Hawaiian lawyer Lanny Sinkin on behalf of several groups, including the Hawai'i Green Party and the Florida Coalition for Peace and Justice, claimed that the risks of an accident were much higher than what NASA documents claimed and that the space agency had not everything possible to reduce the risks.
     However, federal judge David Ezra ruled that NASA had done a careful job evaluating the risks, and the benefits of launching Cassini far outweighed the risks. A final attempt to stop the mission with an injunction failed before a three-judge panel of 9th U.S. Circuit Court of Appeals in San Francisco hours before the launch.
     The ruling on the injunction last Saturday came one week after the biggest anti-Cassini rally to date, outside the gates of the Cape Canaveral Air Station. Estimates of the crowd ranged from 500 to over a thousand, generally smaller than estimated and not as large past protests at the Cape. Twenty-five people were arrested for trespassing when they passed through the gate or scaled the fence at the Air Force facility.
     Cassini now begins its journey to Saturn, where it will arrive in July 2004. Its trajectory includes two flybys of Venus, one of Earth in August 1999, and one of Jupiter. Once there the spacecraft will spend at least four years studying the planet, its rings, magnetic fields, and moons, including the giant moon Titan. The European-built Huygens probe will be dropped by Cassini into Titan's atmosphere in the early months of the mission.

[Ed. Note: for more information on the Cassini mission and the RTG Debate, visit SpaceViews' Cassini Web site at http://www.seds.org/spaceviews/cassini/]

The shuttle Atlantis completed its Mir docking mission earlier this month, exchanging crew members and supplies with the Russian space station, although the highlight of the mission may have come shortly after the shuttle undocked from the station.
     Crews on both Atlantis and Mir photographed evidence of a possible leak in the Spektr module near the base of the damaged solar panel October 3. With the shuttle undocked and stationed just 80 meters (250 feet) from the damaged module, the Mir crew pumped air into the module, flushing some debris through a hole in the module into space, where it was photographed.
     The air-pumping experiment was performed twice. The first time a small cloud of debris was noticed and photographed by the Atlantis crew. On the second attempt only a single piece was seen escaping from the hole.
     The base of the damaged solar panel had been suspected as one location of the hole which depressurized the Spektr module after a June 25 collision with a cargo module, but no leak was noticed in a spacewalk last month outside the module by Anatoly Solovyov and Michael Foale. The exact location of the leak will not be pinpointed until a detailed analysis of the images taken during the leak tests is performed.
     The discovery capped a successful docking mission between the shuttle and Mir, the seventh such docking mission since mid-1995. The shuttle brought several tons of supplies, including food, water, equipment, and a new computer system, to the station.
     The docking mission, STS-86, also brought to an end astronaut Michael Foale's four-month stay on the aging space station. Foale, who endured the Spektr depressurization, computer failures, and other problems, was replaced on the station by David Wolf. Wolf will spend four months on the station and will be replaced by Andy Thomas, the last American to stay on Mir.
     The docking mission also included a joint American-Russian spacewalk outside the station, when Scott Parazynski and Vladimir Titov retrieved experiments attached to the station on another shuttle mission 18 months ago and also left behind parts for any future Mir repairs. Other than a minor problem with Parazynski's tether, the five-hour walk, staged from the shuttle, went well.
     Atlantis returned to Earth with a 5:55pm EDT landing Monday, October 6. The landing was delayed one day when cloudy skies prevented a landing as scheduled on Sunday evening.

Project managers for the Mars Global Surveyor have temporarily suspended the aerobraking maneuvers for the Mars-orbiting spacecraft while they investigate a problem with one of the spacecraft's solar panels.
     Engineers at JPL raised the orbit of the spacecraft October 12 from 120 km (75 mi.) to 170 km (105 mi.) to stop the series of passes through the upper atmosphere that was slowly circularizing Global Surveyor's orbit. The move came after one of the craft's solar panels, which never fully deployed, experienced "unexpected" motion.
     "We're taking a hiatus from aerobraking for the next few weeks while we study data to try to model and understand the apparent deflection of the solar panel that never fully deployed after launch," Glenn Cunningham, project manager for Mars Global Surveyor, said October 14.
     Data from the spacecraft apparently indicate the panel moved beyond the position at which it would have latched into place, fully deployed. The panel also appeared to move during aerobraking, instead of remaining rigid. Both problems were discovered during an aerobraking pass October 6, when the Martian atmosphere was twice as dense as expected.
     The orbit change puts the spacecraft beyond the uppermost reaches of the Martian atmosphere, which means the panel will not be subjected to additional forces while engineers diagnose the problem. Both solar panels continue to generate electrical power without any reported problem.
     Problems with the solar panel date back to shortly after launch last November, when it failed to deploy properly. The panel was stuck at a 20 degree angle from its proper position. Mission managers at the time decided not to take any action, since the panel seemed fixed in place and its ability to generate power was not affected.
     The aerobraking delay means the spacecraft will end up in a somewhat different final orbit than planned. "This delay in the aerobraking process will probably change the spacecraft's final mapping orbit from the originally planned 2 pm local Mars time passage to another time," Cunningham said. "Several other options are being considered, all of which should return "nearly the same quality of science results."
     While the aerobraking portion of the mission is delayed, other science projects involving the spacecraft, which entered orbit around Mars last month, will continue. "We will take advantage of this opportunity to return some spectacular data from the camera and laser altimeter," Cunningham said,. Other instruments on the spacecraft will also continue to collect data.