Interplanetary Dust Storm

In August 1995, when the Galileo Orbiter was 63 million kilometers (39 million miles) from Jupiter, it entered the most intense interplanetary dust storm ever observed. The storm was so large that it took several months for the spacecraft to journey through it. During normal interplanetary travel, a spacecraft comes across about one dust particle every three days. In plowing through the most severe of the several storms that Galileo encountered, the spacecraft counted up to 20,000 particles per...

Eilene Theilig Galileo Project Manager

I really like watching people presented with a problem, and using their creativity to overcome it. And we've had lots of examples of that The people who work, here are really dedicated. It's not just a job.48 -Eilene Theilig, former Galileo Project Manager What Eilene Theilig enjoyed about working on the mission was that it changed character every few years. The spacecraft always presented her and the rest of the team with challenges, as did the evolving complexion of the mission the six-year...

Developing New Missions During a Time of Decreasing Budgets

Planning for post-Apollo missions took place in a context of declining support, both fiscal and political, for NASA's programs. The country's euphoric excitement over space exploration began to lessen after 1965, along with NASA's budget. In the words of Bruce Murray, who became the Director of JPL in 1976, there was less willingness to gamble on the future as did John Kennedy when he created the Apollo program in 1961. The U.S. became a divided country in terms of presidency versus Congress,...

John R Casani Galileo Project Manager

I love the interaction with these people. Brilliant, creative people, with lots of challenges. Still trying to do stuff that's never been done before. -John Casani in an interview with the author on 29 May 2001 When John Casani was a 20-year-old student at the University of Pennsylvania in 1952, he read a series of articles in Colliers' magazine that had a pivotal effect on his life. These were articles by Wernher von Braun, the German rocket engineer who came to the United States after World...

The First Design Changes and Delays

Galileo engineers identified the need for changes to the spacecraft design almost immediately after the mission began. The first project review in October 1977, as well as subsequent reviews, revealed that the combined Orbiter-Probe spacecraft required modifications that would make it significantly heavier than originally planned. For instance, project engineers decided that it was necessary to build a vented rather than pressurized Probe atmospheric entry vehicle in order to enhance...

Why Galileos HGA Rib Restraint Pins Stuck in Their Sockets

From the mass of data it collected, the anomaly team developed a credible scenario for the failure of Galileo's HGA to deploy. The first step in the failure mechanism was postulated to be deformation of the restraint pins. Whenever the antenna was folded into its stowed position, the restraint pins were pushed tightly into their sockets. Plastic deformation of the contact points on some of the pins may have resulted, damaging their Tiodized coatings, which were supposed to provide good bonding...

Bill ONeil Galileo Project Manager

Some of the sen ior engineers in the Probe area, when that signal came to say that everything worked, they actually were crying. -Bill O'Neil, former Project Manager of Galileo For Bill O'Neil, who was Galileo's Project Manager from 1990 until 1997, nothing on the mission was more exciting than Jupiter Arrival Day, especially the Probe's plunge into the Jovian atmosphere. All the chips were on the table that day For five months we'd had no idea of the condition of the Probe. Due to Jupiter's...

The Pioneer Missions

In January 1968, an important step toward outer planet exploration was taken when NASA initiated planning for two missions using Pioneer-series spacecraft that would eventually reach Jupiter and points beyond. The spacecraft were to function in some ways as scouts for future, more intensive outer planet exploration missions (such as Galileo). One objective of the Pioneer missions was to study the asteroid belt between Mars and Jupiter. This region was considered a potential hazard for...

Making the Shuttle Safe To Fly The Need for New Management

One major step in getting the Shuttle safely back into space was to examine the management structures that had led to the Challenger disaster. The presidential investigating commission headed by William Rogers found that NASA managers at Marshall Space Flight Center had repeatedly ignored warnings about the potential for the booster rupture that destroyed Challenger. Marshall had isolated itself from the rest of NASA's management structure, according to the panel. This attitude was nothing new....

Focal Point

Cutaway schematic of the SSI. Shows principal optical components, chargecoupled device detector, particle radiation shield, and front aperture. (JPL 230-537) The Uvs searched for evidence of certain complex hydrocarbon molecules in the Jovian atmosphere that, on Earth, were building blocks for life. In its investigation of the Galilean satellites Io, Europa, Ganymede, and Callisto, the UVS searched for evidence of atmospheres. Such evidence could indicate that volatiles were...

Dick Spehalski Galileo Project Manager

If we had launched in 1986, if the Challenger had worked and we had been able to launch on schedule, we would have found out that Galileo's thrusters would fail. We would probably have lost the mission. -Dick Spehalski, former Project Manager of Galileo The most exciting moment of the Galileo mission for Dick Spehalski was the launch, or, more specifically, the countdown before the launch. Spe had been on the project since its official start date in 1977 and, in his managerial functions under...

Antinuclear Groups Try To Block the Launch

As Galileo's scheduled October 1989 launch date approached, public concern about sending radioactive materials into space flared up into open opposition. Residents of the area surrounding Cape Kennedy, Florida, allied with environmental as well as disarmament groups from around the nation, focused their attention on stopping the launch. Humans and technology can fail, said Bruce Gagnon, coordinator of the Florida Coalition for Peace and Justice. We don't want Brevard County, the Space Coast or...

Selecting a New Trajectory

Without Centaur, a direct flight to Jupiter was impossible. The available solid-fueled upper stage options simply weren't powerful enough to propel Galileo on a direct Earth-Jupiter trajectory. Gravity-assists were required for the spacecraft to attain a trajectory that would get it to Jupiter.41 Because of the need for gravity-assists, JPL analyzed new trajectory options in conjunction with its investigation of launch vehicle alternatives. Using planetary gravity fields to adjust Galileo's...

The Tape Recorder Crisis

Galileo's reel-to-reel tape recorder was originally intended to serve only as a backup to the high-gain antenna (HGA), which was supposed to send images to Earth in near-real time. But the failure of the HGA to unfurl left the Galileo team dependent on data storage and slow data transmission through the spacecraft's low-gain antennas (LGAs). The tape recorder became a vital link in the strategy developed to work around the HGA's problems. Critical data remained stored on the recorder's 560...

Back to Earth

On 8 December 1992, two years after its last Earth encounter, Galileo once more flew by our planet, passing within 300 kilometers (190 miles) above the South Atlantic and using Earth's gravity to swing it onto a direct trajectory to Jupiter. The accuracy of Galileo's flyby maneuver was phenomenal. The spacecraft passed within 1 kilometer of its aimpoint, and as a result, a post-Earth trajectory correction maneuver (TCM-18) was canceled. This saved approximately 5 kilograms (11 pounds) of...

JPL Takes Over the Management of the Jupiter Orbiter Probe Effort

NASA management considered various factors in deciding which of NASA's Centers would manage the Jupiter Orbiter Probe (JOP) project. According to John Casani, Galileo's first Project Manager, all of the Centers had certain roles that represented their core mission responsibilities. Some centers were designated as 'research,' said Casani, and some as 'operational.' JPL's role was operational to conduct planetary missions while the role of Ames Research Center, which also wanted the JOP project,...

Jupiter Orbit Insertion JOI

After the Orbiter finished receiving data from the Atmospheric Probe, it had to adjust its trajectory quickly to avoid heading off into deep space, away from the planet and satellites it was supposed to study. The Orbiter had to fire its 400-newton engine in such a way as to slow itself down relative to Jupiter and allow the giant planet's gravitational field to capture it. NASA scientists scheduled this burn when the Orbiter was close to Jupiter, only four Jupiter radii (RJ ) distant, for the...

Galileos Final Approach

In the weeks before Arrival Day, telescopes around the world prepared to make as many observations as possible of Jupiter in order to best determine what the Atmospheric Probe was heading into. The international effort included the Swedish Telescope at La Palma in the Canary Islands, Mt. Wilson in California, the French observatory Pic-du-Midi in the Pyrenees, Mauna Kea in Hawaii, Yerkes Observatory near Chicago, the McMath Solar Telescope at Kitt Peak in Arizona, and others.45 According to...

Bob Mitchell Galileo Project Manager

When the Challenger explosion accident occurred, we found ourselves in a situation . . . where we didn 't have any way to get to Jupiter Now we just took th is on as kind of our o wn personal challenge. -Bob Mitchell, former Galileo Project Manager After the Challenger tragedy took place in January 1986 and after NASA management decided, a few months later, that it was too dangerous to fly the Centaur upper stage in the Shuttle, Galileo mission staff found themselves in trouble. The...

A

Launch of Galileo liftoff of the Space Shuttle Atlantis, carrying the Galileo spacecraft and its Inertial Upper Stage. (STS34(S)025) Figure 4.5. Launch of Galileo liftoff of the Space Shuttle Atlantis, carrying the Galileo spacecraft and its Inertial Upper Stage. (STS34(S)025) The theme of the Galileo mission was accomplishment in the face of adversity. Even after the successful launch of Atlantis, deployment of Galileo, and firing of its IUS, there was trouble. Heavy winds were...

Could a Europan Ocean Support Life

Once the existence of an ocean beneath the ice crust of Europa was suspected, a most tantalizing question arose both within and outside the space science community Might life exist on Europa The three main factors that exobiologists seek when searching for extraterrestrial life are water, organic compounds, and adequate heat. The presence of a liquid-water ocean would satisfy the first criterion, and organic compounds are known to be prevalent in our solar system. As to the third criterion,...

Attempts To Free the Antenna

In addition to modeling the root causes of the HGA failure, the anomaly team also developed possible strategies for overcoming the problem. Although the stuck ribs could have been easily freed had the spacecraft still been on Earth, it was a bit more complicated to set them loose from many millions of miles away. Mission staff could accelerate the spacecraft, change its orientation, and exert some control over the antenna's mechanical drive system, but they could do little else and had to build...

And The Great Flybys That Almost Werent

Much to the delight of scientists around the country, Galileo survived its Prime Mission and continued to perform beautifully. Two more Io missions were planned during the Galileo Europa Mission, after the spacecraft had had a chance to study Europa in detail. The missions were much anticipated, but the observations that were planned almost did not happen. During the 124 and 125 flybys, the first Io encounters since Jupiter Arrival Day, problems arose that once again threatened to ruin the...

Analysis of the Problem

On the same day that the Galileo flight team tried to open the HGA and realized there was a problem, JPL formed an HGA deployment anomaly team from its staff of mechanical, electrical, thermal, materials design, reliability, and flight operations specialists. JPL also drew in personnel from Harris Corporation, which had built the HGA. By 30 April, the anomaly team had reviewed all videos taken from the Shuttle of Galileo's deployment, trying to determine the status at that time of the HGA and...

Info

Hord and Ian Stewart, University of Colorado 1. Galileo's Science Instruments, Galileo Home Page, (accessed 19 February 2001). 2. Institute of Geophysics and Planetary Physics, UCLA, Galileo Magnetometer Project Overview, Galileo Magnetometer Team's Homepage, (accessed 2 January 2001). 3. Ultraviolet Spectrometer, Galileo Messenger (June 1983). 4. The PPR Finding More Than Meets the Eye, Galileo Messenger (August 1989). Near Infrared Mapping Spectrometer. NIMS analyzed Jovian cloud strata...

Should the HGA Anomaly Have Been Prevented

An analysis of the HGA anomaly by John F. Kross in the periodical Ad Astra concluded that human error led to the antenna's failure to open. The problem should have been anticipated, Kross wrote. After all, the molybdenum disulfide lubricant was applied just once, nearly a decade before launch. Travel is notoriously fraught with risk When asked if this excess travel was ever addressed as a potential problem, project manager William O'Neil claims, 'I believe that the travel induced lubricant...

Using Gravity Assists To Minimize Propellant Requirements

Project engineers had the task of steering the spacecraft along its satellite tour so that it could fly by one moon after another with a minimum expenditure of fuel. The better 24 JPL, The Tour, p. 65. Galileo mission support crew interview. 27 Brad Compton, Galileo mission control team chief, interview, JPL, 5 August 2001. the engineers were at their job, the longer the craft could operate assuming that its other systems held together . To minimize propellant use, each satellite encounter was...

Growing a JOP Project

NASA's Jupiter Orbiter with Probe Marketing Plan, written by Dan Herman around the end of 1975, outlined the steps that would be taken to support the start of a JOP project in FY 1978. These steps included the following Forming a science working group CJOPSWG to define m ission objectives and outline probe and orbiter payload requirements. JOPSWG was chaired by James Van Allen and began meeting in the first half of 1976. Issuing a Request for Proposal RFP for Phase-B Probe development. After...

Principal Investigator And Organization

Determine abundance ratio of helium to hydrogen. Obtain temperature, pressure, and density profiles atmospheric mean molecular weight wind velocities and wind shear and turbulence intensity and scale. Alvin Sieff, NASA Ames Research Center Determine chemical composition and physical state measure vertical variations. Hasso Niemann, NASA Goddard Space Flight Center Measure vertical distribution of solar energy and planetary emissions, locate cloud layers, and use infrared to study cloud and...

The Grand Tour Concept

Shortly after the National Academy of Sciences panel met, there was a discovery that greatly enhanced both public and government interest in an outer planet mission. In 12 Space Research, p. 50 Waff, A History of Project Galileo, p. 11 Butrica, Voyager The Grand Tour of Big Science, p. 253. 13 Space Research, pp. 47-51 Waff, A History of Project Galileo, p. 11. 14 Space Research, pp. 51-52, 59-60. late summer of 1965, a Caltech graduate student demonstrated that Jupiter, Saturn, Uranus, and...

Adapting Centaur to the Shuttle

Design studies integrating Centaur with the Shuttle date back to the start of the Shuttle program, although when Boeing's solid-fueled IUS was the favored upper stage, prospects for a Centaur-driven Galileo spacecraft seemed very remote. When General Dynamics finally received the go-ahead in 1982 for full-scale Centaur adaptation to the Shuttle, it had to fulfill both NASA's requirements and those of the Air Force. The result was two versions of the upper stage the G type for the Air Force and...

Centaur Is Canceled

On 19 June 1986, NASA Administrator James Fletcher delivered a huge blow to American space science and to Galileo in particular by canceling the l-billion Shuttle Centaur program. This decision ended the development of the hydrogen-powered satellite booster that was supposed to send Galileo and other spacecraft from low-Earth orbit into a planetary trajectory. The venerable Centaur, with its track record of reliability, was deemed unsafe for use in the Shuttle due to concerns regarding its...

Pin and Socket Analysis

The anomaly team used pin and socket pairs from an extra, non-flight-ready HGA at JPL to evaluate the various failure scenarios. Vibrational testing had previously been performed on the extra HGA, and so the pin and socket pairs already should have experienced considerable relative motion. Visual inspection of pins from the spare HGA revealed some plastic deformation. X-ray diffraction scans of a number of the pins indicated that both the Tiodize ceramic coating and the molybdenum disulfide...

Naming the Orbits of Jupiter

The Galileo mission used a two-character code to specify each orbit. The first character was the first letter of the name of the moon that would receive a flyby on the orbit, while the second character indicated the number of the orbit. Table 9.2 lists the code name for each Jupiter orbit on the Prime Mission satellite tour, the satellite encountered during the orbit, and the date of closest approach to the satellite. Note that on the fifth orbit J5 , no close satellite encounter occurred.31...