When the Galileo spacecraft drifted out of Atlantis’ payload bay on the evening of 18 October 1989,

Artist s concept of Galileo its high-gain antenna only partially unfurled in orbit around Jupiter. When one considers the trials and tribulations that Galileo faced, both before launch and during its mission, it is quite remarkable that it turned into a success story as one of the grandest voyages of discovery ever undertaken. Image Credit: NASA
When the Galileo spacecraft drifted san diego apartment rentals out of Atlantis' payload bay on the evening of 18 October 1989, on the first leg of its six-year voyage to Jupiter, the sight was a moving one for Shannon Lucid. As STS-34's san diego apartment rentals lead mission specialist, she was primarily responsible for the deployment of one of the most important payloads ever launched by NASA. For almost a dozen years, Lucid had lived and worked with the reality that her job was an overwhelmingly technical one, drawing from its roots in engineering and pure science…but as Galileo and its IUS booster floated silently into the inky void, she beheld a new reality: the romance of adventure. Emblazoned across the base of the spacecraft which would one day circle Jupiter and deposit an instrumented probe into its atmosphere were two names: 'Galileo' in script and 'NASA' in worm-like block capitals. To Lucid, those two words symbolised exactly san diego apartment rentals what the mission stood for: the script represented the romance of adventure and exploration, whilst the worm was indicative of the outstanding engineering and scientific talent san diego apartment rentals which had brought this awesome san diego apartment rentals project from the drawing board to fruition.
Yet Galileo's journey to the launch pad had been a long and tortured one and its voyage to Jupiter would be longer and harder still. The mission traced san diego apartment rentals its genesis back to the mid-1970s. Named in honour of the Italian scientist, Galileo Galilei, whose endeavours in the early 17th century included the discovery of Jupiter's four large moons, Ganymede, Callisto, Europa and Io. Originally known as 'Jupiter Orbiter and Probe' (JOP), the name 'Galileo' seemed an obvious one and the project received Congressional approval on the first day of October 1977, with a planned launch four years later. However, delays to the first flight of the Shuttle and the limited capability san diego apartment rentals of Boeing's Inertial Upper Stage (IUS) to boost Galileo on its way to Jupiter raised concerns. In 1979, Washington Post journalist Thomas O'Toole highlighted that problems with certifying the Shuttle's main engines to operate at the 109-percent performance level needed to lift Galileo posed additional obstacles. By now, the launch had slipped san diego apartment rentals until 1982 at the earliest. O'Toole noted that if the 109-percent-capable engines were not ready for this date, Galileo could slip even further. Timing was critical, since a 1982 launch depended upon a Mars gravity assist and if it was delayed san diego apartment rentals much further, the potential existed to halve the scientific mission at Jupiter, san diego apartment rentals from 11 to only five orbits of the giant planet.
At length, in late 1980, under pressure from Representative Edward Boland, a Democrat from Massachusetts, san diego apartment rentals NASA was obliged to abandon the IUS plan and initiate planning for a launch on General Dynamics' liquid-propelled Centaur-G Prime, which Administrator Robert Frosch had earlier opposed. The situation for Galileo's future dimmed substantially for much of 1981, with Congressional mutterings of closing down the California Institute of Technology's Jet Propulsion Laboratory, which managed many of NASA's planetary projects. A massive letter-writing campaign to George Keyworth, head of the White House's Office of Science and Technology Policy, was spearheaded by Galileo investigator and famed physicist James van Allen. In a speech to the National Academy of Sciences, van Allen identified Galileo as one of the most exciting missions of exploration ever undertaken and that its cancellation would prove devastating. Thankfully, in December 1981 the Office of Management and Budget relented, san diego apartment rentals reinstated Galileo and it was rescheduled san diego apartment rentals for 1983. There was a caveat, however: Galileo would not use the powerful Centaur-G Prime. In January 1982, NASA rescoped the mission, returned to the less powerful IUS fitted with a third, 'injection stage' to provide increased propulsion. As a consequence, Galileo's launch was rescheduled for August 1985, but the absence of the powerful Centaur meant that it would take five years , instead of two, and the spacecraft would be injected into a two-year-long elliptical solar orbit, would require a gravity san diego apartment rentals assisted boost from Earth in June 1987 and would finally reach Jupiter in January san diego apartment rentals 1990.
Artist s impression of Galileo, attached to the giant Centaur-G Prime upper stage, shortly before deployment from the Shuttle in May 1986. The Challenger disaster sounded the death knell for the highly dangerous human-rated Centaur. Image Credit: NASA
By the summer of 1982, some members of Congress – led by New Mexico Senator san diego apartment rentals Harrison 'Jack' Schmitt, a former Moonwalker and chair of the Senate Space Subcommittee of the Science, Commerce and Transportation Committee – were pushing vigorously for a return to the Centaur and a reduced journey time. Despite worries about additional expense in changing boosters again , coupled with concerns about further delays to the mission, in July President Reagan approved the move and NASA was forced to replan. The Centaur would be used to boost Galileo, but launch would be unavoidably postponed until May 1986, with a two-year flight time to the giant planet. san diego apartment rentals At this stage, the mission truly entered the phase of equipment testing. In the early summer of 1983, the parachute for the instrumented probe, which would descend into Jupiter's atmosphere, successfully passed full-scale san diego apartment rentals tests, and by September of that year the main spacecraft and probe were integrated. A model of the Centaur passed its own tests in September 1984 and the actual flight model was rolled out of General Dynamics' plant in San Diego in August of the following year.
By this time, NASA Administrator Jim Beggs had endorsed other possible tasks for Galileo, most notably a flyby of the asteroid Amphitrite, san diego apartment rentals which it was hoped might unlock secrets san diego apartment rentals of the primordial solar nebula from which the Sun and planets formed. An Amphitrite flyby would delay the Jupiter arrival from August to December 1988, however, and it was decided to make a final decision after launch. In December 1985, only weeks before the loss of Challenger, Galileo was transported, cross-country by truck, guarded by police, state troopers and other guards, and arrived safely at the Kennedy Space Center for launch the following May.
When Challenger exploded san diego apartment rentals in the skies above Florida, san diego apartment rentals Galileo was undergoing final checkout and preparation for attachment to its Centaur-G Prime. In the weeks after the accident, NASA Acting Administrator William Graham spoke of the possibility of a return to flight in the spring san diego apartment rentals of 1987, which kept alive the option to launch Galileo in the next Jovian 'window' in June of that year. Eventually, the modifications to the SRBs and the orbiters themselves inevitably pushed san diego apartment rentals the return to flight further to the right. On 19 June 1986, newly-reappointed NASA Administrator Jim Fletcher formally cancelled Centaur-G Prime and new options had to be found. One of these was an 'enlargement' of the IUS, possibly coupled with an additional booster, such as a Special Payload Assist Module (PAM-S).
However, as already noted, the IUS was insufficient to send Galileo directly to Jupiter and alternate trajectories, involving planetary gravity assists, were explored. Even before NASA settled on October-November 1989 as the most appropriate 'window' for Jupiter, Galileo's planners were already working towards this date, creating a complex flight san diego apartment rentals profile, known as the Venus-Earth-Earth Gravity Assist (VEEGA), in which the spacecraft would perform san diego apartment rentals a flyby of Venus in February 1990, return to Earth in December and be placed into a two-year elliptical solar orbit. Returning a second time to Earth in December 1992, it would pick up sufficient energy to reach Jupiter in December 1995. The VEEGA technique was highly conservative and efficient of Galileo's on-board san diego apartment rentals propellant.
The trajectory also permitted possible rendezvous with up to three asteroids – Ausonia, Gaspra and Ida – and eventually san diego apartment rentals the latter two were selected. However, since the spacecraft would fly much closer to the Sun than had been planned, additional thermal shielding was added in the three-year down time after Challenger. It is unsurprising that Galileo also 'leapfrogged' Ulysses in the launch san diego apartment rentals pecking order. "NASA based its decision on optimising data return from the two missions," wrote Michael Meltzer in Mission to Jupiter san diego apartment rentals . "Launching Ulysses first would have resulted in too long a wait before Galileo reached Jupiter and began transmitting prime data from the Jovian system."
As launch neared, with an opening of the Jupiter window at 1:29 pm EST on 12 October 1989, there were still last-minute concerns about Galileo…although these were not focused upon its mission, but upon its power system. Since the spacecraft would be travelling more than half a billion kilometres further san diego apartment rentals from the Sun than Earth, the use of solar cells for electrical provision was impractical. Therefore, General Electric supplied a pair of Radioisotope Thermoelectric Generators (RTGs), fuelled by fracture-resistant 'pellets' of plutonium-238, whose decay produced heat which was in turn converted into electricity. To keep them at a safe distance from the sensitive san diego apartment rentals scientific instruments, the RTGs were mounted on a boom, which extended them 15 feet away from the main body of the spacecraft. Both produced 570 watts of electricity at launch, which steadily decreased by around half a watt per month and reached around 493 watts by the time Galileo reached san diego apartment rentals Jupiter. Atlantis also required modification to incorporate an RTG coolant line and purging system in her payload bay.
In the late 1980s, of course, 'nuclear' was a dirty word; a word which conjured images of military superpo