From the "JPL Universe"
December 15, 1995
The NASA TV picture focused on a half-dozen or so tense, anticipatory faces, all huddled around computer screens in the Mission Support Area of Building 264, waiting for the word. It was just after 3 p.m. on Dec. 7. Would the Galileo orbiter receive the probe's signal, indicating a successful entry into Jupiter's atmosphere?
Then, when the positive news came at 3:10, years of pent up hope and anticipation burst out into celebratory applause and handshakes. Project Manager William O'Neil, Mission Director Neil Ausman, Deputy Mission Director Matt Landano and others celebrated the confirmation that the orbiter had indeed begun its two-year mission by parachuting into the giant planet's clouds.
"The data we received is a status indicator to show us that the probe was working and that it was transmitting data to the mother ship," O'Neil said. About three hours later, at 6:08 p.m., the news was equally worthy of celebration: Galileo had successfully fired its engines for 49 minutes, enabling it to enter orbitaround Jupiter. Finally, the spacecraft's two-year mission was under way.
The celebration resounded throughout the Laboratory. Galileo team members and their families were joined by more than 1,000 invited guests in watching news conferences and mission commentary on JPL's television monitors, and all shared the triumphant moment with hugs, back-slapping and broad smiles.
And why not? The mission that was conceived in the mid-70s and finally launched in 1989 had, at long last, successfully reached its destination. "We are all absolutely ecstatic that our tremendously ambitious, first-ever penetration of an outer planet atmosphere has been so wonderfully successful," O'Neil said. "It's especially gratifying because so many of us have worked so hard for nearly two decades to get this first true taste of Jupiter's atmosphere."
Indications on Sunday, Dec. 10, were that the probe transmitted data to the mothership for 57 minutes during the probe's plunge into the atmosphere. Receipt of probe data began at 4:15 a.m. that day. The probe data represent the first-ever direct measurement of the planet's atmosphere and should reveal details of Jupiter's composition, climate and circulation. Forty minutes of data collected by the probe stored in the orbiter's onboard computer memory were radioed to Earth over a four-day period.
The first scientific results from the probe data are to be presented in a briefing on Dec. 19 at Ames Research Center in Moffett Field, Calif., which developed the probe and is the lead NASA center for data analysis. [Note: this briefing has been postponed due to the government shutdown].
Another event that took place Dec. 7 was Galileo's flyby of the Jovian moon Io. The spacecraft flew within 892 kilometers (555 miles) of Io, 45 kilometers closer and five seconds sooner than expected. "That's pretty good, considering we were 600 million miles away," O'Neil quipped.
The Io maneuver was performed to slow down the orbiter and reduce the amount of propellant needed for orbit insertion. O'Neil said 90 kilograms of propellant were saved by the flyby, and that Galileo will carry out its first flyby of the moon Ganymede on June 27, 1996, a week earlier than the July 4 flyby previously scheduled.
Other indicators of Galileo's status on Dec. 7, O'Neil noted, showed no Jovian environment-induced events or autonomous fault protection actions, and that normal readings were taken on power margin, tank pressures and temperatures, as well as subsystems operation. "It's been just a perfect day, but one that was very hard-earned," he said. Galileo Mission Director Neal Ausman added, "Every Galileo achievement that we have shared with the world is the result of teamwork. The team has time and time again overcome problems thought to be catastrophic."
O'Neil said he expects that no orbit trim adjustments will be required to alter Galileo's orbital path prior to the so-called perijove raise maneuver, the third and last burn of the spacecraft's 400-Newton main engine scheduled for March 1996. That long-planned maneuver is designed to lift Galileo's orbit out of the high-radiation environment of Jupiter's charged-particle belts, which could damage the spacecraft's electronics.
"I can't wait to read newspaper reports over the next two years about these tremendous contributions the space agency is making to the knowledge of humankind," said NASA Administrator Daniel Goldin, addressing a packed von Karman Auditorium. "I wish I could personally shake the hand of everyone who had a role in this tremendous mission.
"Congratulations to all, and thanks for sharing it with us."
Including JPL employees who stayed after work to view a wrapup press briefing at 6:45 p.m., almost 2,000 people ended up packing von Karman Auditorium as well as cafeterias and conference rooms, said JPL Public Services Office Manager Kim Lievense.
She said approximately 900 "family and friends" of Galileo team members were on hand.
Other guests of note included Dr. Wesley Huntress Jr., associate administrator for Space Science; Galileo Program Manager Donald Ketterer; and Don Williams, retired commander of STS-34 (Space Shuttle Atlantis), the mission that launched Galileo in October 1989. Many retired JPL assistant Laboratory directors and project managers also were on hand.
Community leaders included officials from the chambers of commerce and city councils of La Canada, Pasadena, Glendale and Altadena. Educators from the Los Angeles and Pasadena Unified School Districts were in attendance, as were officials from the Planetary Society, California Museum of Science and Industry and California Science Teachers Association.
Reporters and crews from Italy, Germany, England and Finland joined those from throughout the United States, providing local and national coverage for newspapers, magazines, television, radio and wire services. Film documentary crews also were on Lab during and after the Galileo activities.
In addition, users from 68 countries accessed the Galileo home page more
than 250,000 times on Dec. 7; two days later, a peak of more than 336,000
accesses were recorded.
Through Dec. 11, more than 2 million accesses to the home page were made in
December, already surpassing the monthly record of accesses set last year for
the Shoemaker-Levy 9 impacts of Jupiter. [Through Dec 18, the number of accesses
is now over 3.5 million]
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