Mission Overview
================
The Galileo mission utilized a single launch of a combined
Orbiter and Probe using the space shuttle Atlantis and an
inertial upper stage (IUS) to inject the Galileo spacecraft on
its interplanetary trajectory to Jupiter. The launch occurred
October 18, 1989. Since the IUS did not have the energy to
inject Galileo on a direct trajectory to Jupiter, the spacecraft
was launched first towards Venus for the first leg of its
Venus-Earth-Earth gravity assist (VEEGA) trajectory.

Target-of-opportunity science observations were made at Venus
(closest approach February 10, 1990), the first Earth encounter
(closest approach to Earth and Moon December 8 and 9, 1990), the
asteroid Gaspra (closest approach October 29, 1991), the second
Earth encounter (closest approach to Earth and Moon December 8,
1992), the asteroid Ida (closest approach August 28, 1993), and
distant observations of the impact of comet Shoemaker-Levy 9 into
Jupiter's atmosphere from July 16-22, 1994.

The Probe separated from the Orbiter on July 13, 1995. After
this time, the Probe proceeded on a ballistic trajectory to its
entry point (6.54 deg north latitude, 4.46 west longitude) into
the atmosphere of Jupiter. The Orbiter used its 400 Newton
engine on July 27, 1995 to perform a deflection maneuver to keep
from following the Probe into the atmosphere of Jupiter, and to
retarget the Orbiter to the proper encounter conditions required
for the Jupiter Orbit Insertion phase of the mission.

A close flyby (892 kilometer altitude) of the Jovian satellite
Io occurred at 17:45:58 UT on Dec 7, 1995, during the Jupiter
Orbit Insertion phase. This flyby allowed fields and particles
science observations to be made and slowed the Orbiter down
relative to Jupiter by nearly 200 meters/second in order to
reduce the propellant required during the Jupiter Orbit Insertion
(JOI). Remote sensing observations of Io were not made at this
time due to an anomaly with the onboard tape recorder associated
with high speed recording that was not well understood at the
time of the flyby. Perijove at 4.00 Jupiter radii occurred at
21:53:44 UT on the same day. A few minutes after perijove
passage, the Probe entered the Jovian atmosphere and began
relaying data back to the Orbiter.

The Probe mission and data relay lasted 58.6 minutes, after
which JOI was performed, slowing the Orbiter down relative to
Jupiter by about 630 meters/second. The initial orbit period was
about 200 days. A large 400 Newton engine burn was performed at
the first apojove in order to raise perijove from 4 Jupiter radii
to about 9 Jupiter radii, thus allowing the mission to complete
10 targeted satellite encounters without exceeding the allowed
total accumulated radiation exposure at the spacecraft. This
limit would have been exceeded after three orbits if perijove had
been allowed to stay at 4 Jupiter radii, where the radiation
environment is very severe.

Prime Mission orbital operations consisted of 10 targeted satellite
encounters over 24 months. During the course of the satellite
tour, the orientation, shape and size of the spacecraft orbits
around the Jovian system, referred to as petals because of how
the spacecraft orbits appear on an equatorial projection of the
Jovian satellite tour trajectory, were controlled almost
exclusively by gravity assists of the satellites themselves.
The orbit periods were pumped down by successive encounters
with the satellites from the initial 200 days to approximately
35-40 days between encounters. During the 9th orbit, when the
orbit petal orientation was approximately in the anti-sun
direction, the period was again pumped up to about 100 days
which allowed one of the primary objectives, probing the Jovian
magnetotail, to be accomplished. After this magnetotail orbit,
the period was again pumped down, by gravity assist encounters
with the Jovian satellites, to 35-40 days for the final
targeted encounters. (Refer to GLLMS1991, GLLSRD1989, and
GLLIOM1992).

The Galileo Europa Mission (GEM) was a low cost follow-on to the
Galileo Prime Mission that uses the Galileo spacecraft to continue
focused studies of the Jovian system. The mission is divided
into three main phases or campaigns: Europa Campaign, Perijove
Campaign and Io Campaign. Each had a different and very specific
scientific focus. Towards the end of the GEM an additional mission
extension was proposed to NASA to keep the Galileo spacecraft in
operation through the Jupiter flyby of the Cassini spacecraft in
December 2000. The orbital tour was extended to prolong the Io
phase by 2 orbits and to add another 2 orbits for Galileo and
Cassini collaborative science.

The Galileo Millennium Mission (GMM) was a follow on to the GEM
mission, with a greatly reduced budget. The mission was designed
to continue the exploration of Io and the inner Jovian
magnetosphere, and to dispose of the spacecraft in an
environmentally friendly manner (Jupiter impact). Jupiter impact
occurred on September 21, 2003 at approximately 19:07 UTC. The
last science packets were received a few hour earlier at
14:31:54 UTC.

The Galileo orbits were named by concatenating the first letter
of the name of the primary target in each orbit with the orbit
number. Thus, the fourth Jupiter orbit, in which Europa is the
primary target, is called E4. The project defined orbits
according to spacecraft command load boundaries rather than the
normal convention of apoapsis to apoapsis. The navigation team
did not always adhere to this convention, causing some confusion.

The PDS organized the data and data delivery schedule around the
project defined orbit boundaries. Table 1 contains information
about the full Galileo orbital tour.

_______________________________________________________________
Table 1 Orbital Facts
_______________________________________________________________
Periapsis Periapsis Satellite Satellite
Orbit Range* (Rj) Date/Time Closest Approach Flyby
(Rj=71492km) (UT) Date/Time (UT) Alt** (km)
_______________________________________________________________
J0 4.00 95-341 21:53:44 95-341 17:45:58 896
G1 11.03 96-180 00:31:26 96-179 06:29:07 838
G2 10.65 96-251 13:37:54 96-250 18:59:34 264
C3 9.21 96-311 13:31:07 96-309 13:34:28 1138
E4 9.16 96-354 03:21:58 96-354 06:52:58 688
J5 9.05 97-020 00:26:57 N/A N/A
E6 9.12 97-051 20:54:15 97-051 17:06:10 582
G7 9.12 97-094 11:03:38 97-095 07:09:58 3104
G8 9.27 97-128 11:41:46 97-127 15:56:10 1606
C9 10.77 97-178 11:52:22 97-176 13:47:50 421
C10 9.17 97-261 23:10:00 97-260 00:18:55 538
E11 8.97 97-311 00:42:01 97-310 20:31:44 2039
E12 8.80 97-350 06:34:53 97-350 12:03:20 201
J13 8.86 98-041 23:09:15 N/A N/A
E14 8.84 98-088 07:59:13 98-088 13:21:05 1644
E15 8.85 98-152 02:34:42 98-151 21:12:57 2514
E16 8.85 98-202 00:17:59 98-202 05:03:45 1834
E17 8.91 98-269 08:26:27 98-269 03:54:20 3582
E18 8.94 98-326 07:30:52 98-326 11:38:26 2271
E19 9.11 99-032 05:02:10 99-032 02:19:50 1439
C20 9.37 99-123 17:00:11 99-125 13:56:18 1321
C21 7.27 99-183 05:04:52 99-181 07:46:50 1048
C22 7.32 99-224 10:58:31 99-226 08:30:52 2299
C23 6.54 99-257 19:57:37 99-259 17:27:02 1052
I24 5.55 99-284 02:02:37 99-284 04:33:03 611
I25 5.7 99-330 02:07:41 99-330 03:59:15 300
E26 5.8 00-004 03:32:58 00-003 17:59:56 360
I27 5.9 00-053 12:30:23 00-053 13:46:36 200
G28 6.7 00-142 04:52:29 00-141 10:10:18 900
G29 7.5 00-364 03:26:31 00-363 08:25:27 2338
C30 7.3 01-143 17:32:51 01-145 11:23:58 138
I31 5.9 01-218 04:52:11 01-218 04:59:21 194
I32 5.8 01-288 23:55:59 01-289 01:23:21 184
I33 5.5 02-017 16:22:31 02-017 14:08:23 100
A34 2.0 02-309 07:23:22 02-309 06:18:26 914
J35 0.9 03-264 18:57 03-264 19:07:00 N/A


* Range is measured from center of mass
** Altitude is computed by subtracting a satellite radius from a
measured range. Variations in reported values may be
attributed to differences in the radius value subtracted
(estimates improve).

The failed deployment of the Galileo High Gain Antenna
necessitated fundamental changes in how the spacecraft acquired
and transmitted data back to Earth if more than a fraction of the
science objectives were to be met. Changes were required to both
the spacecraft software (Command Data System (CDS) and Attitude
and Articulation Command System (AACS)) and many of the science
instruments software. The mission can be described in terms of
three distinct sets of flight software (FSW) which are commonly
called Phase 0 FSW, Phase 1 FSW, and Phase 2A FSW. The Galileo
flight software phases should not be confused with Mission Phases
which will be describe later.

Phase 0: Initial spacecraft flight software configuration at
launch. Telemetry was sent in a Time-Division-Multiplex (TDM) or
Fixed-format mode. The data rates in this phase were designed to
be supported by the high gain antenna and had very limited
capability to return science data at telemetry rates below 7.68
kbps. The Phase 0 flight software was patched on June 15, 1993
to increase the memory readout block size from 32 bytes to 80
bytes.

Phase 1: The Phase 1 flight software consisted of minor
modifications of Phase 0 to improve the data return from the
Galileo probe. It was loaded onto the spacecraft January 30
through February 12, 1995. The changes provided for: the
capability to write edited Probe symbol data and Doppler wind
data to the extended memory of the primary onboard computer, new
downlink telemetry rates at 8 bps and 16 bps, a new 7.68 kbps
Probe data record format, 80 byte memory readouts to decrease
data return time, and more robust fault protection during the
time of Relay/JOI.

Phase 2A: The Phase 2 flight software is fundamentally different
from the Phase 0 flight software. The purpose of the changes was
to utilize the low gain antenna more effectively to return
science data. There were two major categories of change: 1) to
return data from the tape recorder in a more efficient and
autonomous fashion, and 2) to provide a real time capability for
the fields and particles science instruments. More than 58% of
the onboard computer memory was loaded with new code. The new
capabilities included packetized telemetry with advanced
Reed-Solomon encoding, 8 downlink rates from 8 to 160 bps, new
tape recorder record formats, automated and adaptive playback
modes, science data selection, sampling, summation and
compression, and 9 low rate real-time science downlink formats.

Real time editing of optical navigation images was also
provided. Eight of the science instruments also developed new
flight software in support of the changing spacecraft
capabilities in Phase 2. Select science instruments were
provided with automated loading of their onboard stored, mode
dependent software. While the Phase 2 flight software was in
testing, problems were discovered with the tape recorder.

Additional features were added to the flight software to manage
the tape recorder to avoid the known failure mechanisms and to
avoid unwrapping the tape which had been damaged in the
spacecraft anomaly of October 11, 1995. The final flight
software delivery which included the tape recorder modifications
was called Phase 2A. The Phase 2A flight software was loaded
onto the spacecraft from May 18-22, 1996. The instrument Phase 2
software loads were completed by May 26, 1996.

Numerous anomalies occurred on the Orbiter during this mission
that impacted data return but did not fundamentally change the
mission. Some of the science objectives listed below were not
achieved as a result of these anomalies. Please check the
Galileo Europa Mission instrument host catalog for additional
information on spacecraft anomalies.


Mission Phases
==============

LAUNCH AND DEPLOYMENT
---------------------
Galileo was launched on October 18, 1989 at 16:53:39 GMT
aboard the Space Shuttle Atlantis (OV-104), flight STS-34.
An Inertial Upper Stage (IUS-19) placed Galileo on its Earth-
to-Venus trajectory. Following the IUS burn, Galileo
configured itself for solo flight and separated from the IUS
on October 19, 1989 at 01:06:53 GMT. (Refer to [GLLMS1991]).
After IUS separation, the spacecraft underwent an outgassing
period prior to powering on the science instruments. The
instruments were turned on later and data were acquired to
verify that each instrument was operational. The commanding
of this process was more complicated than most command
sequences since the exact launch date and time were not known
in advance. The launch and deployment mission phase covers
the same time period as was covered by the command sequences
LAUNCH and EV0 (Earth-Venus 0).

Spacecraft Id : GO
Target Name : VENUS
Mission Phase Start Time : 1989-10-17T00:00:00
Mission Phase Stop Time : 1989-10-26T16:00:00


INTERPLANETARY CRUISE
---------------------
The trajectory of the spacecraft from Earth to Jupiter was
dictated by the limited propulsion capability allowed within
the Space Shuttle to boost the spacecraft from Earth orbit to
an interplanetary trajectory. This limit prevented a direct
trajectory from Earth to Jupiter; instead a 'VEEGA' trajectory
was used to achieve the energy necessary to send Galileo to
Jupiter. The acronym VEEGA is from the trajectory description:
Venus-Earth-Earth Gravity Assist. In this trajectory, Galileo
passes Venus once, then flies by Earth twice, thus obtaining
three gravity assists before heading toward Jupiter. (Refer to
[SSR1992].) The Earth-Jupiter Cruise phase includes the
following phases: Earth-Venus Cruise, Venus Encounter,
Venus-Earth Cruise, Earth1 Encounter, Earth-Earth Cruise,
Gaspra Encounter, Earth2 Encounter, Earth-Jupiter Cruise, Ida
Encounter, Shoemaker-Levy 9 Encounter, Probe Release.

Spacecraft Id : GO
Target Name : JUPITER
Target Name : VENUS
Target Name : EARTH
Target Name : IDA
Target Name : GASPRA
Target Name : SL9
Mission Phase Start Time : 1989-10-26T16:00:00
Mission Phase Stop Time : 1995-10-09T00:00:00


EARTH-VENUS CRUISE
------------------
The Earth-Venus Cruise phase occurred during the
Interplanetary Cruise phase. It lasted from the end of the
Launch sequence to February 19, 1990. This phase included
the encounter with the planet Venus.

Spacecraft Id : GO
Target Name : VENUS
Mission Phase Start Time : 1989-10-26T16:00:00
Mission Phase Stop Time : 1990-02-19T00:00:00


4-DAY CHECKOUT
--------------
The 4-Day Checkout phase occurred during the Earth-Venus
portion of Interplanetary Cruise phase. This was the first
time the science instruments were turned on and permitted to
check their health after launch. Calibration data exists for
all instruments from this period.

Spacecraft Id : GO
Target Name : N/A
Mission Phase Start Time : 1989-12-27T00:00:00
Mission Phase Stop Time : 1989-12-31T00:00:00


VENUS ENCOUNTER
---------------
The Venus Encounter phase occurred during the Interplanetary
Cruise phase. A 12-day single load sequence provided the
sequencing resources for the Venus encounter. Most of the
data gathered were put onto the onboard tape recorder, since
the high gain antenna had to remain furled behind its
sunshade during this near-sun activity, and the low gain
antenna did not have the performance for real-time science
data transmission to Earth during the Venus encounter. The
Venus encounter data were played back to Earth in November
1990, when Galileo was close enough to Earth that science
data rates could be achieved over the low gain antenna.
Upstream energetic particles were detected, bowshock
crossings were indicated, and the plasma wave instrument saw
evidence of lightning discharges. Eighty-one images by the
Solid State Imaging experiment were taken, which proved
useful in atmospheric motion studies. In addition, the Venus
encounter yielded radio tracking data which have been
analyzed by the Radio Science (Celestial Mechanics) Team to
obtain a mass estimate for Venus. In contrast to the other
experiments, the Radio Science data were not stored on the
spacecraft recorder, but were available in real time on Earth
for analysis. (Refer to [GLLMS1991]). Closest approach to
Venus occurred February 10, 1990 at an altitude of 16,123 km.
at 05:58:48 UTC.

Spacecraft Id : GO
Target Name : VENUS
Time of closest approach : 1990-02-10T05:58:48
Mission Phase Start Time : 1990-02-07T00:00:00
Mission Phase Stop Time : 1990-02-19T00:00:00


VENUS-EARTH CRUISE
------------------
The Venus-Earth Cruise phase occurred during the
Interplanetary Cruise phase. It included the interplanetary
cruise from Venus, around the sun, and back to and past the
Earth. This phase also included the first Earth encounter.
The primary science gathering during this period was
performed through EUV, DDS, MAG and the USO Redshift
experiments. In November 1990, as the spacecraft approached
the first Earth encounter, the three DMS tracks of Venus data
were successfully played back.

The High-Gain Antenna Deployment planned for April 11, 1991
was unsuccessful, most likely due to an incomplete release of
three HGA ribs. Future attempts for rib release were then
scheduled for Earth-Earth Cruise.

Spacecraft Id : GO
Target Name : EARTH
Target Name : MOON
Mission Phase Start Time : 1990-02-19T00:00:00
Mission Phase Stop Time : 1991-04-29T00:00:00


EARTH1 ENCOUNTER
----------------
The first Earth gravity assist occurred on December 8, 1990
at a flyby altitude of 960 km at 20:34:35 UTC. The Moon
encounter occurred on December 9, 1990 at a flyby altitude of
346,608 km at 2:28:21 UTC.

The spacecraft trajectory took Galileo virtually up the
Earth's magnetotail, providing unprecedented opportunity for
fields and particles measurements. The plasma science
experiment results brought into question the validity of the
previous assumption that the bulk flows of the ion and
electron plasmas in the distant magnetotail are identical.
Spectral mapping observations of Australia and Antarctica
were made by the near infrared mapping spectrometer. A first
ever time-lapse movie, in six colors, of the rotating Earth
over a period slightly greater than one day was made by the
Solid State Imaging experiment. Multispectral imaging of the
western nearside and eastern farside of the Moon were
obtained by the SSI. These data showed that Orientale Basin
ejecta deposits are similar to typical highlands deposits
such as the soils at the Apollo 16 site, while observations
of the South Pole-Aitken basin interior contain
characteristics that appear distinctively different from that
of nearside maria, thus providing new information on mare
deposits on the limb and farside of the Moon.

Spacecraft Id : GO
Target Name : EARTH
Time of closest approach : 1990-12-08T20:34:35
Target Name : MOON
Time of closest approach : 1990-12-09T02:28:21
Mission Phase Start Time : 1990-11-08T00:00:00
Mission Phase Stop Time : 1990-12-16T00:00:00


EARTH-EARTH CRUISE
------------------
The Earth-Earth cruise phase occurred during the
Interplanetary Cruise phase. It included the interplanetary
cruise from Earth, around the sun, and back to and past the
Earth a second time. Key activities included the on-going
HGA Recovery effort, which proved unsuccessful, encounters
with the asteroid Gaspra as well as with Earth, collection of
cruise science data, SSI cover and EPD shade deployments and
opportunities for radio science experiments at spacecraft
conjunction and opposition.

Spacecraft Id : GO
Target Name : EARTH
Target Name : MOON
Target Name : GASPRA
Mission Phase Start Time : 1991-04-29T00:00:00
Mission Phase Stop Time : 1993-04-12T00:00:00


GASPRA ENCOUNTER
----------------
The Gaspra Encounter phase occurred during the Interplanetary
Cruise phase and the Earth-Earth Cruise phase. On 29 October
1991 Galileo passed Gaspra at a distance of approximately
1,600 km and a speed of approximately 30,000 km per hour.
Color and black and white images were taken of Gaspra as well
as measurements to indicate composition and physical
properties. The data were stored on the spacecraft tape
recorder and later played back to Earth.

Spacecraft Id : GO
Target Name : GASPRA
Time of closest approach : 1991-10-29T22:36:46


EARTH2 ENCOUNTER
----------------
The Earth2 Encounter phase occurred during the Interplanetary
Cruise phase and the Earth-Earth Cruise phase. The second
Earth encounter provided an opportunity to gather Earth and
Lunar science and perform instrument calibrations.
Additionally, during this period Galileo participated in the
GOPEX deep space laser communication experiment. The flyby
altitude of Moon was 110,267 km on December 8, 1990 at
3:57:45 UTC. The flyby altitude of the Earth was
approximately 304 km at 15:09:25 UTC.

Spacecraft Id : GO
Target Name : EARTH
Time of closest approach : 1992-12-08T15:09:25
Target Name : MOON
Time of closest approach : 1992-12-08T03:57:45
Mission Phase Start Time : 1992-11-08T00:00:00
Mission Phase Stop Time : 1992-12-20T00:00:00


EARTH-JUPITER CRUISE
--------------------
The Earth-Jupiter Cruise phase occurred during the
Interplanetary Cruise phase. It covered the period from
April 12, 1993 to October 8, 1995. The second Earth
encounter places the spacecraft on a direct trajectory to
Jupiter. Again, the spacecraft passed through the Asteroid
Belt. This transit included an August 1993 encounter with
the 32-km.-diameter, S-type, main-belt asteroid, Ida. The
Earth-Jupiter Cruise phase included the following phases: Ida
Encounter, Shoemaker-Levy 9 Encounter, Probe Release and ODM.

Spacecraft Id : GO
Target Name : JUPITER
Target Name : IDA
Target Name : SL9
Mission Phase Start Time : 1993-04-12T00:00:00
Mission Phase Stop Time : 1995-10-09T00:00:00


IDA ENCOUNTER
-------------
The Ida Encounter phase occurred during the Interplanetary
Cruise phase and the Earth-Jupiter Cruise phase. Galileo
flew by Ida in the southern hemisphere (75 degrees south
ecliptic latitude) on the asteroid's dark side, passing
approximately 2400 km (1500 mi) from the center of the
asteroid while traveling at a speed relative to the asteroid
of 12.4 km/sec (27,700 mph). During closest approach, Ida
appeared from Earth to be located at Right Ascension: 196.7
degrees; Declination: -8.0 degrees toward the constellation
Virgo. Ida is 3-4 degrees northwest of Spica, Virgo's
brightest star.

Spacecraft Id : GO
Target Name : IDA
Time of closest approach : 1993-08-28T16:52:05


SHOEMAKER-LEVY 9 ENCOUNTER
--------------------------
The Shoemaker-Levy 9 Encounter phase occurred during the
Interplanetary Cruise phase and the Earth-Jupiter Cruise
phase. Shoemaker-Levy 9 was a comet that broke into multiple
pieces during its passage by Jupiter in July 1992. On July
16,1994 these fragments began to impact Jupiter. It is
estimated that between 20 and 25 struck the planet.
Observations were made by the following instruments: NIMS,
SSI, PPR, PWS, UVS (there was no EUV data). MAG and DDS
conducted observations over a longer period of time.

Spacecraft Id : GO
Target Name : SL9
Mission Phase Start Time : 1994-07-16T00:00:00
Mission Phase Stop Time : 1994-07-22T00:00:00


PROBE RELEASE AND ODM
---------------------
The Probe Release Encounter phase occurred during the
Interplanetary Cruise phase and the Earth-Jupiter Cruise
phase. The Probe was released on July 13, 1995 at 05:30:00
UTC, which was ~150 days before Jupiter Orbit Insertion
(JOI). Fourteen days after release, July 27th, the Orbiter
performed an Orbit Deflection Maneuver (ODM) of about 60
m/sec to place it on a trajectory which overflew the Probe
during its entry and descent. The ODM was the first use of
the 400 N engine.

Spacecraft Id : GP
Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 1995-07-05T00:00:00
Mission Phase Stop Time : 1995-07-31T00:00:00


JUPITER ORBIT OPERATIONS
------------------------
The Jupiter Orbit Operations phase encompasses all mission phases
where the spacecraft was acquiring Jupiter science data. It
includes all of the Jupiter approach, Prime mission, GEM mission,
and GMM mission phases through impact on September 19, 2003.

Spacecraft Id : GO
Target Name : JUPITER
Target Name : AMALTHEA
Target Name : IO
Target Name : CALLISTO
Target Name : GANYMEDE
Target Name : EUROPA
Mission Phase Start Time : 1995-10-09T00:00:00
Mission Phase Stop Time : 2003-09-21T19:07:00


PRIME MISSION ORBIT OPERATIONS
------------------------------
Jupiter arrival occurred on December 7, 1995. Arrival day at
Jupiter was characterized by a rapid series of high-priority
engineering and science events. Much of the science that was
unique to this orbit (science requiring remote sensing data)
was lost due to an anomaly with the onboard tape recorder.
No science data were acquired during the 32,000 km
non-targeted encounter of Europa. About 4 1/2 hours after
the Europa fly-by, the spacecraft then flew within about 1000
km of Io. Fields and particles data were recorded for
approximately 3 hours in the vicinity of Io. The flyby was
also designed to provide a gravity assist which reduced the
delta-V necessary to achieve orbit around Jupiter.

The probe entry occurred a little over 4 hours after the Io
encounter. During the descent of the Probe its data were
relayed to the Orbiter. Probe Relay lasted 58.6 minutes and
was followed about one hour later by the JOI burn. Probe
data were played back from the tape recorder on the orbiter
twice over the next several months to ensure that no Probe
data were lost. Another hour of fields and particles science
data were recorded after probe relay in conjunction with the
JOI maneuver.

At apojove of the insertion orbit, a large Perijove Raise
Maneuver (PJR) increased the perijove altitude of the orbit
and targeted the spacecraft for its first encounter. After
this time, the trajectory was primarily shaped by close
encounters with Ganymede, Callisto, and Europa. Ten such
close encounters, one per orbit, plus a one-month 'phasing
orbit' which occurred between the Europa 4 encounter and the
Europa 6 encounter were planned over the 24 months of the
orbital mission. There was no targeted encounter during the
phasing orbit. There were several non-targeted encounters
(at ranges of tens to hundreds of thousands of kilometers) of
the Galilean satellites, Jovian atmospheric and
magnetospheric measurements throughout the tour, and a large
'tail petal' orbit designed to explore the Jovian
magnetotail.

Spacecraft Id : GO
Target Name : JUPITER
Target Name : IO
Target Name : CALLISTO
Target Name : GANYMEDE
Target Name : EUROPA
Mission Phase Start Time : 1995-10-09T00:00:00
Mission Phase Stop Time : 1997-12-15T00:00:00


JUPITER APPROACH
----------------
The Jupiter Approach phase occurred during the Jupiter Orbit
Operations phase. An image of Jupiter was taken on approach;
however, shortly afterwards there was an anomaly with the
onboard tape recorder which prohibited the return of that
image. The only science data acquired on approach was from
DDS, EUV and MAG.

Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 1995-10-09T00:00:00
Mission Phase Stop Time : 1995-12-03T00:00:00


JUPITER 0 ORBIT
---------------
The Jupiter 0 Orbit phase occurred during the Jupiter Orbit
Operations phase. Jupiter arrival occurred on December 7,
1995. Arrival day at Jupiter was characterized by a rapid
series of high-priority engineering and science events. Much
of the science that was unique to this orbit (science
requiring remote sensing data) was lost due to an anomaly
with the onboard tape recorder. No science data were
acquired during the 32,000 km non-targeted encounter of
Europa. About 4 1/2 hours after the Europa fly-by, the
spacecraft then flew within about 1000 km of Io. Fields and
particles data were recorded for approximately 3 hours in the
vicinity of Io. The flyby was also designed to provide a
gravity assist which reduced the delta-V necessary to achieve
orbit around Jupiter.

The probe entry occurred a little over 4 hours after the Io
encounter. During the descent of the Probe its data were
relayed to the Orbiter. Probe Relay lasted 58.6 minutes and
was followed about one hour later by the JOI burn. Probe
data were played back from the tape recorder on the orbiter
twice over the next several months to ensure that no Probe
data were lost. Another hour of fields and particles science
data were recorded after probe relay in conjunction with the
JOI maneuver.

At apojove of the insertion orbit, a large Perijove Raise
Maneuver (PJR) increased the perijove altitude of the orbit
and targeted the spacecraft for its first encounter.

Spacecraft Id : GO
Target Name : JUPITER
Target Name : IO
Mission Phase Start Time : 1995-12-03T00:00:00
Mission Phase Stop Time : 1996-06-23T00:00:00


IO 0 ENCOUNTER
--------------
The Io 0 encounter phase occurred during the Jupiter 0 Orbit
operations phase. The spacecraft flew past Io at an altitude
of less than 900 km. Much of the science that was unique to
this orbit (science requiring remote sensing data) was lost
due to an anomaly with the onboard tape recorder. This was
the only close flyby of Io during the mission. Fields and
particles data were recorded for approximately 3 hours in the
vicinity of Io. Another hour of fields and particles science
data were recorded after probe relay while still in the Io
torus. In addition to providing science data, the flyby was
designed to provide a gravity assist which reduced the
delta-V necessary to achieve orbit around Jupiter.

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 1995-12-07T17:45:58
Mission Phase Start Time : 1995-12-03T00:00:00
Mission Phase Stop Time : 1996-01-03T00:00:00


PROBE
-----
The Probe phase occurred during the Jupiter Orbit Operations
phase. The probe entry occurred a little over 4 hours after
the Io encounter. During the descent of the Probe its data
were relayed to the Orbiter where is was stored on tape. The
data were later replayed and transmitted to Earth. The Probe
Relay lasted 58.6 minutes and was followed about one hour
later by the JOI burn. For a more complete description of
the Galileo Probe mission, please refer to [YOUNGETAL1996].

Spacecraft Id : GP
Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 1995-12-07T22:01:00
Mission Phase Stop Time : 1995-12-07T23:22:00


GANYMEDE 1 ORBIT
----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 1996-06-23T00:00:00
Mission Phase Stop Time : 1996-09-01T00:00:00


GANYMEDE 1 ENCOUNTER
--------------------
Objectives: Wake, Alfven Wing, start of first magnetospheric
mini-tour, remote Io torus observations, plasma sheet
crossing at 25 Rj, Ganymede and Europa geology and
atmospheric properties, Io monitoring, distant Callisto
observations, gravity, Great Red Spot, Jupiter northern and
southern aurora, Io footprint, reduce period.
Altitude: 838 km, Latitude: 30.39 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 1996-06-27T06:29:07
Mission Phase Start Time : 1996-06-23T00:00:00
Mission Phase Stop Time : 1996-06-30T00:00:00


GANYMEDE 2 ORBIT
----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 1996-09-01T00:00:00
Mission Phase Stop Time : 1996-11-02T00:00:00


GANYMEDE 2 ENCOUNTER
--------------------
Objectives: North Alfven wing, Jovian radio emissions, first
mini-tour of Jovian magnetosphere continues, remote Io torus,
plasma sheet crossing at 40 Rj, unique Ganymede north polar
pass, Europa low- phase global images, Io monitoring,
Callisto, Amalthea, stratospheric circulation, Jupiter
southern aurora, Shoemaker-Levy 9 remnant material images,
gravity, reduce inclination.
Altitude: 264 km, Latitude: 79.29 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 1996-09-06T18:59:34
Mission Phase Start Time : 1996-09-01T00:00:00
Mission Phase Stop Time : 1996-09-08T00:00:00


CALLISTO 3 ORBIT
----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1996-11-02T00:00:00
Mission Phase Stop Time : 1996-12-15T00:00:00


CALLISTO 3 ENCOUNTER
--------------------
Objectives: Wake and Alfven Wing, completion of first
mini-tour of Jovian magnetosphere, Jupiter aurora, remote Io
torus, Callisto Asgard Basin, Europa non-targeted encounter -
volcanism observations, closest Io approach of tour, gravity,
UVS counter-rotate, white oval observations, Jupiter northern
aurora, Jupiter atmosphere during solar occultation.
Altitude: 1138 km, Latitude: 13.19 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1996-11-04T13:34:28
Mission Phase Start Time : 1996-11-02T00:00:00
Mission Phase Stop Time : 1996-11-11T00:00:00


EUROPA 4 ORBIT
--------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1996-12-15T00:00:00
Mission Phase Stop Time : 1997-02-16T00:00:00


EUROPA 4 ENCOUNTER
------------------
Objectives: Wake and northern Alfven wing, north to south
plasma sheet crossing, remote Io torus, excellent Europa
dayside and nightside coverage, Io partial eclipse, Jupiter
rings, Amalthea, Thebe, Adrastea, northern equatorial belt
hot spot, Europa & Jupiter occultations, Jupiter northern
aurora.
Altitude: 688 km, Latitude: -1.65 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1996-12-19T06:52:58
Mission Phase Start Time : 1996-12-15T00:00:00
Mission Phase Stop Time : 1996-12-22T00:00:00


EUROPA 6 ORBIT
--------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1997-02-16T00:00:00
Mission Phase Stop Time : 1997-03-30T00:00:00


EUROPA 6 ENCOUNTER
------------------
Objectives: South Alfven wing, Jupiter magnetic equator
crossing, Europa Argiope Linea and other lineated regions, Io
plume monitoring, Jupiter rings, Thebe, Amalthea, south
equatorial belt-zone region, Jupiter northern aurora, Europa,
Io, and Jupiter occultations.
Altitude: 582 km, Latitude: -17.02 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1997-02-20T17:06:10
Mission Phase Start Time : 1997-02-16T00:00:00
Mission Phase Stop Time : 1997-02-23T00:00:00


GANYMEDE 7 ORBIT
----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 1997-03-30T00:00:00
Mission Phase Stop Time : 1997-05-04T00:00:00


GANYMEDE 7 ENCOUNTER
--------------------
Objectives: North Alfven Wing, first dawn-side plasma sheet
at 46 Rj, start of second mini-tour of Jovian magnetosphere,
Ganymede high-energy impact regions (Kittu, etc.), Europa
non-targeted encounter, Callisto full-color mosaic, visually
clear or Brown Barge regions, Jupiter northern aurora.
Altitude: 3104 km, Latitude: 55.80 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 1997-04-05T07:09:58
Mission Phase Start Time : 1997-03-30T00:00:00
Mission Phase Stop Time : 1997-04-06T00:00:00


GANYMEDE 8 ORBIT
----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 1997-05-04T00:00:00
Mission Phase Stop Time : 1997-06-22T00:00:00


GANYMEDE 8 ENCOUNTER
--------------------
Objectives: Upstream wake crossing, continue second mini-tour
of Jovian magnetosphere, plasma sheet/Jupiter aurora at 20
Rj, Ganymede surface morphology: Osiris, Tiamat Sulcus, etc.,
Callisto non-targeted encounter south pole, Metis, Elara,
south polar haze zone, Jupiter northern and southern aurora,
Io footprint, Ganymede & Jupiter occultations.
Altitude: 1606 km, Latitude: 28.27 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 1997-05-07T15:56:10
Mission Phase Start Time : 1997-05-04T00:00:00
Mission Phase Stop Time : 1997-05-11T00:00:00


CALLISTO 9 ORBIT
----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1997-06-22T00:00:00
Mission Phase Stop Time : 1997-09-14T00:00:00


CALLISTO 9 ENCOUNTER
--------------------
Objectives: Unique deep magnetotail passage of 143 Rj,
continue second mini-tour of Jovian magnetosphere, Jupiter
aurora, Callisto Valhalla multi-ringed structure, Ganymede
non-targeted encounter, Metis, Adrastea, Amalthea, Thebe,
Great Red Spot, equatorial plume head, Io footprint, high
solar phase angle of Jovian atmosphere, Callisto & Jupiter
occultations.
Altitude: 421 km, Latitude: 1.96 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1997-06-25T13:47:50
Mission Phase Start Time : 1997-06-22T00:00:00
Mission Phase Stop Time : 1997-06-29T00:00:00


CALLISTO 10 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1997-09-14T00:00:00
Mission Phase Stop Time : 1997-11-02T00:00:00


CALLISTO 10 ENCOUNTER
---------------------
Objectives: Wake and Alfven Wing, continue second mini-tour
of Jovian magnetosphere, Jupiter magnetic equator crossing,
Callisto global and bright limb observations, Io aurora and
Jupiter rings during solar occultation, Europa volcanism
survey, Amalthea, Thebe, Adrastea, Metis, north polar haze
region, Jupiter aurora and lightning during solar
occultation.
Altitude: 538 km, Latitude: 4.60 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1997-09-17T00:18:55
Mission Phase Start Time : 1997-09-14T00:00:00
Mission Phase Stop Time : 1997-09-20T00:00:00


EUROPA 11 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1997-11-02T00:00:00
Mission Phase Stop Time : 1997-12-15T00:00:00


EUROPA 11 ENCOUNTER
-------------------
Objectives: Combined Europa fly-by and magnetic equator
crossing for fields & particles instruments, end of second
mini-tour of Jovian magnetosphere, Jupiter auroral map
campaign, Brown Barge campaign, northern aurora oval,
lightning detection campaign, ring observations, Io
monitoring, Europa Pwyll, Mannann'an wedge and bright planes,
Earth occultation.
Altitude: 2039 km, Latitude: 25.73 degrees N

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1997-11-06T20:31:44
Mission Phase Start Time : 1997-11-02T00:00:00
Mission Phase Stop Time : 1997-11-09T00:00:00



EUROPA CAMPAIGN
---------------

The Europa campaign was comprised of eight (E12-E19) close
fly-bys ranging in flyby altitudes from 200 to 3600 km. The
latitudes achieved during these flybys range from -43 degrees to
+42 degrees. Extensive remote sensing and fields and particles
science data gathering was attempted at each of these encounters
except for E13 which was too close to solar conjunction. E13
flyby science was limited to the collection of geophysical data
via the radio system (Doppler). E13 cruise was used for E12 data
playback during those during those periods where the Sun-Earth-
Craft (SEC) angle is greater than 7 degrees. Spacecraft safings
in the E16 and E18 orbits severly compromised the planned science
return from those orbits. After the spacecraft was reconfigured
from safing the remainder of the orbits were used to return data
not played back from the preceding orbit and to acquire fields &
particles real time science data. The primary science objective
in the Europa phase was the return of unique Europa data.
However, Jupiter atmospheric observations were added to two
orbits.

Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1997-12-15T00:00:00
Mission Phase Stop Time : 1999-05-02T00:00:00
Spacecraft Operations Type : ORBITER


EUROPA 12 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1997-12-15T00:00:00
Mission Phase Stop Time : 1998-02-09T00:00:00


EUROPA 12 ENCOUNTER
-------------------
Objectives: Europa's Pwyll crater, Conamara Chaos, search for
hot spots and tenuous atmosphere, surface composition maps,
mottled wedges terrain, dark lineas, plateaus,
satellite/magnetosphere interaction, gravity field measurement.
Closest Galileo flyby to any celestial body. Jupiter's upper
atmosphere energy budget and longitudinal spectral scans. Io
eclipse, Ganymede Gilgamesh basin. Inner magnetosphere survey.
Altitude: 201.0 km, Latitude: -8.66 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1997-12-16T12:03:20
Mission Phase Start Time : 1997-12-15T00:00:00
Mission Phase Stop Time : 1997-12-17T00:00:00


EUROPA 13 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-02-09T00:00:00
Mission Phase Stop Time : 1998-03-28T00:00:00


EUROPA 14 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-03-28T00:00:00
Mission Phase Stop Time : 1998-05-30T00:00:00


EUROPA 14 ENCOUNTER
-------------------
Objectives: Europa's Mannann'an crater, Tyre macula, triple
bands, dark spots, bright plains, day and night thermal maps,
surface composition maps, search for tenuous atmosphere,
satellite/magnetosphere interaction, gravity field measurement.
Jupiter's north polar aurora and longitudinal spectral scans.
Io full disk, north and south pole, eclipse, and torus.
Ganymede global coverage. Callisto surface composition map.
Inner magnetosphere survey.
Altitude: 1644.1 km, Latitude: 12.21 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1998-03-29T13:21:05
Mission Phase Start Time : 1998-03-28T00:00:00
Mission Phase Stop Time : 1998-03-31T00:00:00


EUROPA 15 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-05-30T00:00:00
Mission Phase Stop Time : 1998-07-20T00:00:00


EUROPA 15 ENCOUNTER
-------------------
Objectives: Europa's Cilix masif, rough terrain, near terminator,
day and night thermal maps, surface composition maps, search for
tenuous atmosphere, satellite/magnetosphere interaction, gravity
field measurement. Jupiter's upper atmosphere energy budget, and
longitudinal spectral scans. Io surface monitoring, Kanehekili
plume, high-solar phase map, eclipse, torus, surface composition,
tenuous atmosphere. Inner magnetosphere survey.
Altitude: 2514.5 km, Latitude: 15.00 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1998-05-31T21:12:57
Mission Phase Start Time : 1998-05-30T00:00:00
Mission Phase Stop Time : 1998-06-03T00:00:00


EUROPA 16 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-07-20T00:00:00
Mission Phase Stop Time : 1998-09-25T00:00:00


EUROPA 16 ENCOUNTER
-------------------
Objectives: Europa's Agenor linea, Thrace macula, Taliesen
crater, dissected terrain, wedges, near-terminator, day and
night thermal maps, surface composition maps, satellite/
magnetosphere interaction, gravity field measurement.
Jupiter cloud structure, atmospheric dynamics and waves,
upper atmosphere energy budget, hot maps, longitudinal
spectral scans. Io monitoring and torus. Ganymede
composition map. Inner magnetosphere survey.
Altitude: 1834.2 km, Latitude: -25.65 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1998-07-21T05:03:45
Mission Phase Start Time : 1998-07-20T00:00:00
Mission Phase Stop Time : 1998-07-29T00:00:00


EUROPA 17 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-09-25T00:00:00
Mission Phase Stop Time : 1998-11-21T00:00:00


EUROPA 17 ENCOUNTER
-------------------
Objectives: Europa's Thynia linea, south pole, strike-slip
faults, near terminator, day and night thermal maps,
surface composition maps, tenuous atmosphere, gravity field
measurement. Jupiter ring observations, south pole aurora,
longitudinal spectral scans, merging white oval, and wave
structure. Io torus and Pele. Inner magnetosphere survey.
Altitude: 3582.4 km, Latitude: -42.43 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1998-09-26T03:54:20
Mission Phase Start Time : 1998-09-25T00:00:00
Mission Phase Stop Time : 1998-09-28T00:00:00

EUROPA 18 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1998-11-21T00:00:00
Mission Phase Stop Time : 1999-01-31T00:00:00


EUROPA 18 ENCOUNTER
-------------------
Objectives: Europa's Radamanthys, south pole plains, north
pole pits and plateaus, massifs, bright and dark plains,
global and regional polarimetry maps, surface composition
maps, tenuous atmosphere, gravity field measurement.
Jupiter upper atmosphere energy budget and longitudinal spectral
scans. Io surface monitoring, polarimetry and torus.
Ganymede polarimetry. Inner magnetosphere survey including
extended dusk side measurements.
Altitude: 2270.8 km, Latitude: 41.34 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1998-11-22T11:38:26
Mission Phase Start Time : 1998-11-21T00:00:00
Mission Phase Stop Time : 1999-11-24T00:00:00


EUROPA 19 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 1999-01-31T00:00:00
Mission Phase Stop Time : 1999-05-02T00:00:00


EUROPA 19 ENCOUNTER
-------------------
Objectives: Europa plume search, hexagonal ice terrain,
near terminator, dark spots, mottled terrain, bright plains,
global and regional polarimetry maps, surface composition maps,
tenuous atmosphere, satellite/magnetosphere interaction,
gravity field measurement. Jupiter cloud structure and
dynamics, stratosphere, upper atmosphere/aurora energy
budget, hot maps, longitudinal spectral scans.
Io polarimetry and torus. Ganymede polarimetry.
Inner magnetosphere survey.
Altitude: 1439.4 km, Latitude: 30.52 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 1999-02-01T02:19:50
Mission Phase Start Time : 1999-01-31T00:00:00
Mission Phase Stop Time : 1999-02-11T00:00:00


PERIJOVE REDUCTION CAMPAIGN
---------------------------

The perijove reduction campaign was comprised of four low
altitude flybys of Callisto (C20-C23). During this campaign,
the spacecraft perijove is reduced from 9.4 Rj (before C20) to
5.5 Rj (after C23), which sets up the spacecraft trajectory
for the subsequent encounters with Io at 5.9 Rj. The primary
science objectives for this phase were in-situ studies of the
torus and selected atmospheric observation.

Spacecraft Id : GO
Target Name : TORUS
Mission Phase Start Time : 1999-05-02T00:00:00
Mission Phase Stop Time : 1999-10-10T00:00:00
Spacecraft Operations Type : ORBITER


CALLISTO 20 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1999-05-02T00:00:00
Mission Phase Stop Time : 1999-06-29T00:00:00


CALLISTO 20 ENCOUNTER
---------------------
Objectives: 2 hr perijove sample (plasma transport mechanisms),
inner magnetosphere survey including dusk region, Io torus.
Jupiter cloud structure and dynamics, atmospheric wave
structure, stratosphere composition, upper atmosphere and
aurora energy budgets, hot maps, longitudinal spectral scans.
Callisto composition, crater statistics, dark flows, radio
science Earth occultation. Io monitoring and composition.
Europa eclipse.
Altitude: 1321.4 km, Latitude: 2.78 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1999-05-05T13:56:18
Mission Phase Start Time : 1999-05-02T00:00:00
Mission Phase Stop Time : 1999-05-07T00:00:00


CALLISTO 21 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1999-06-29T00:00:00
Mission Phase Stop Time : 1999-08-11T00:00:00


CALLISTO 21 ENCOUNTER
---------------------
Objectives: 2 hour perijove sample (plasma transport mechanisms),
inner magnetosphere survey. Jupiter longitudinal spectral scans.
Callisto dark material, ring structures, thermal maps, and
surface composition. Io global composition, thermal and
visual maps, and plume inventory.
Altitude: 421 km, Latitude: 1.96 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1999-06-30T07:46:50
Mission Phase Start Time : 1999-06-29T00:00:00
Mission Phase Stop Time : 1999-07-03T00:00:00


CALLISTO 22 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1999-08-11T00:00:00
Mission Phase Stop Time : 1999-09-13T00:00:00


CALLISTO 22 ENCOUNTER
---------------------
Objectives: 6 hr perijove sample (plasma transport), chorus
wave samples (plasma acceleration), inner magnetosphere survey,
Io torus. Jupiter cloud structure and dynamics, regional maps,
stratosphere composition, aurora energy budgets, hot maps, and
longitudinal spectral scans. Callisto radio science Earth
occultation. Io plume inventory. Europa distant global.
Amalthea best resolution of Galileo mission.
Altitude: 2299.3 km, Latitude: -2.3 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1999-08-14T08:30:52
Mission Phase Start Time : 1999-08-11T00:00:00
Mission Phase Stop Time : 1999-08-14T00:00:00


CALLISTO 23 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 1999-09-13T00:00:00
Mission Phase Stop Time : 1999-10-10T00:00:00


CALLISTO 23 ENCOUNTER
---------------------
Objectives: Fields & particles dedicated orbit. Io torus
7 hr recorded sample, 7.6-6.5 Jupiter radii. Chorus wave
samples (plasma acceleration), inner-outer magnetosphere
12 day survey including dusk region. Callisto radio science
Earth occultation. Jupiter north pole aurora energy budgets.
Altitude: 1052.4 km, Latitude: 0.099 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 1999-09-16T17:27:02
Mission Phase Start Time : 1999-09-13T00:00:00
Mission Phase Stop Time : 1999-09-17T00:00:00



IO CAMPAIGN
-----------

The Io phase had 3 Io flybys (I24,I25,I27) and one Europa flyby
(E26). The first two Io encounters (I24 and I25) were viewed by
the project as the equivalent to Prime Mission objective. The
first of the encounters is characterized by a near-equatorial
flyby of Io followed by near continuous DSN coverage for data
return. This encounter was optimized for the return of remote
sensing data not acquired during the J0 orbit in the Prime
Mission. A deterministic maneuver (delta V ~ 9 m/s) was required
to link the first Io encounter to the second. The second
encounter is characterized by a near-polar flyby of Io optimized
to distinguish if Io has an intrinsic magnetic field.

Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 1999-10-10T00:00:00
Mission Phase Stop Time : 2000-05-20T00:00:00
Spacecraft Operations Type : ORBITER


IO 24 ORBIT
-----------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 1999-10-10T00:00:00
Mission Phase Stop Time : 1999-11-25T00:00:00


IO 24 ENCOUNTER
---------------
Objectives: Io gravity field measurement for interior structure,
high resolution thermal mapping (PPR), imaging volcanic plumes of
Pillan and Pele, high resolution imaging of volcanic centers Loki,
Pele, Pillan, Colchis, Tohil, Prometheus, Zamama, Dorian, Amirani,
Skythia, Gish Bar. Io global and regional radiometry and
polarimetry, regional near-infrared spectral mapping. Io auroral
emissions, surface properties, and atmospheric species. Jupiter-
Io magnetosphere coupling, inner magnetosphere survey including
dusk region, Io torus energetics, Io torus morphology. Jupiter
atmosphere wave structure.
Altitude: 611.2 km, Latitude: 4.51 degrees

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 1999-10-11T04:33:03
Mission Phase Start Time : 1999-10-10T00:00:00
Mission Phase Stop Time : 1999-10-14T00:00:00


IO 25 ORBIT
-----------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 1999-11-25T00:00:00
Mission Phase Stop Time : 2000-01-02T00:00:00


IO 25 ENCOUNTER
---------------
Objectives: Io gravity field measurement for interior structure,
highest resolution imaging of Io during GEM, first south polar
coverage, imaging and monitoring of volcanic features, global and
regional thermal maps, regional near-infrared spectral mapping,
Io auroral emissions, atmospheric and surface properties.
Highest resolution imaging of Amalthea. Jupiter/Io magnetospheric
coupling, inner magnetosphere survey, Io torus morphology, polar
Io magnetic field measurements. First opportunity for imaging
Europa's Jupiter-facing hemisphere. Europa high resolution north
polar imaging of lineaments, dark band pairs, and flow features,
polarimetry for surface textures.
Altitude: 300 km, Latitude: -76.6 degrees

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 1999-11-26T04:05:22
Mission Phase Start Time : 1999-11-25T00:00:00
Mission Phase Stop Time : 1999-11-27T00:00:00


EUROPA 26 ORBIT
---------------
Spacecraft Id : GO
Target Name : EUROPA
Mission Phase Start Time : 2000-01-02T00:00:00
Mission Phase Stop Time : 2000-02-20T00:00:00


EUROPA 26 ENCOUNTER
-------------------
Objectives: Observe Europa's interaction with the Jovian
magnetosphere and examine any induced magnetic field in Europa.
Europa terminator map. Images of Amalthea, Thebe and Metis.
Observations of Loki on Io. Continue return of I25 playback data.
Altitude: 360 km, Latitude: -46.6 degrees

Spacecraft Id : GO
Target Name : EUROPA
Time of closest approach : 2000-01-03T17:59:56
Mission Phase Start Time : 2000-01-01T00:00:00
Mission Phase Stop Time : 2000-01-05T00:00:00


IO 27 ORBIT
-----------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 2000-02-20T00:00:00
Mission Phase Stop Time : 2000-05-17T00:00:00


IO 27 ENCOUNTER
---------------
Objectives: Io Isum Mons and Zamama, 3-color global, high
resolution spectral maps of Pele, Tohil Mons, Amirani, SO2 frost,
polarimetry and spectral mapping of Mulungu region, torus
morphology, aurora and surface and atmospheric properties,
global and regional thermal mapping, gravity field measurements.
Jupiter/Io magnetospheric coupling, inner magnetosphere survey.
Jupiter atmosphere wave structure. Complete I25 torus data
return.
Altitude: 200 km, Latitude: 18.3 degrees.

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 2000-02-22T13:46:36
Mission Phase Start Time : 2000-02-20T00:00:00
Mission Phase Stop Time : 2000-02-25T00:00:00




GALILEO-CASSINI PHASE
---------------------

During the Cassini phase the Galileo flyby geometry changes
considerably in order to decrease the radiation dosage
experienced by the spacecraft. The Cassini phase is so named
as both Galileo and the Cassini spacecraft are in favorable
positions both inside and outside of Jupiter's magnetosphere.
This allows a dual-spacecraft simultaneous study of the Jovian
system for the first time.

Spacecraft Id : GO
Target Name : TORUS
Mission Phase Start Time : 2000-05-17T00:00:00
Mission Phase Stop Time : 2001-02-05T00:00:00
Spacecraft Operations Type : ORBITER


GANYMEDE 28 ORBIT
-----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 2000-05-20T00:00:00
Mission Phase Stop Time : 2000-12-27T00:00:00


GANYMEDE 28 ENCOUNTER
---------------------
Objectives: Jupiter/Ganymede magnetospheric coupling,
measurements of Jovian magnetosphere for comparison with
contemporaneous solar wind measurements by Cassini. Coordinated
investigation of Jovian aurora and auroral variability, high
resolution images of the Great Red Spot for characterization of
wind speeds, high northern latitude occultation of Earth. Ganymede
high resolution imaging, global mapping to complete longitudinal
coverage, limb scan and Earth occultation for detection of an
atmosphere. Low-phase, high tilt ring observations. Io color
imaging and volcano monitoring. Europa global color imaging.
Altitude: 808 km, Latitude: -13.8 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 2000-05-20T10:10:18
Mission Phase Start Time : 2000-05-17T00:00:00
Mission Phase Stop Time : 2000-06-13T00:00:00


GANYMEDE 29 ORBIT
-----------------
Spacecraft Id : GO
Target Name : GANYMEDE
Mission Phase Start Time : 2000-12-27T00:00:00
Mission Phase Stop Time : 2001-05-22T00:00:00


GANYMEDE 29 ENCOUNTER
---------------------
Objectives: Jupiter/Ganymede magnetospheric coupling,
measurements of the dusk-side magnetosphere in collaboration with
Cassini observations obtained while traversing the magnetosphere.
Ganymede auroral features, regional and high-resolution
observations, global observations, eclipse thermal maps. Jupiter
atmospheric motion collaborative observations with Cassini,
near-infrared spectral mapping, Great Red Spot, north equatorial
belt and hot spot observations. Io sodium cloud and eclipse.
Jovian main ring. Io, Europa and Callisto global images
complementing Cassini views.
Altitude: 2338 km, Latitude: -14.8 degrees

Spacecraft Id : GO
Target Name : GANYMEDE
Time of closest approach : 2000-12-28T08:43:07
Mission Phase Start Time : 2000-12-26T00:00:00
Mission Phase Stop Time : 2001-02-05T00:00:00



IO CAMPAIGN (GMM)
-----------------

The Io Phase is comprised of four (C30, I31, I32, and I33)
encounters, one of Callisto and the others of Io, at flyby
altitudes of 100 to 200 km. The Callisto gravity assist sets up
high latitude flybys for I31 and I32 enabling both fields and
particles measurements of a potential intrinsic magnetic field
and unique remote sensing opportunities. With each successive
passage, the orbit migrates farther to the sunward side of
Jupiter. A trajectory correction is planned near I33 apojove
to effect a plane change and decrease orbital inclination.

Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 2001-05-22T00:00:00
Mission Phase Stop Time : 2002-01-20T00:00:00
Spacecraft Operations Type : ORBITER


CALLISTO 30 ORBIT
-----------------
Spacecraft Id : GO
Target Name : CALLISTO
Mission Phase Start Time : 2001-05-22T00:00:00
Mission Phase Stop Time : 2001-08-04T00:00:00


CALLISTO 30 ENCOUNTER
---------------------
Objectives: Make a close flyby of Callisto, using its gravity
assist to lower perijove and set up two polar and one
mid-latitude flybys of Io. Science objectives include Global
Color Imaging, Regional and targeted observations of key geologic
features, Temperature scans to monitor surface warming,
Ionosphere measurements during occultation. Callisto induced
magnetic field. Surface-magnetosphere interactions, Real-time
science monitoring of the inner Jovian magnetosphere and Io
torus, Jupiter cloud dynamics, electron density profiles and the
white oval. Other targets include Ganymede thermal maps, and
near-terminator imaging, and monitoring Io volcanic activity in
daylight and eclipse.
Altitude: 123 km, Latitude: 13.3 degrees

Spacecraft Id : GO
Target Name : CALLISTO
Time of closest approach : 2001-05-25T11:23:55
Mission Phase Start Time : 2001-05-22T00:00:00
Mission Phase Stop Time : 2001-05-27T00:00:00


IO 31 ORBIT
---------------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 2001-08-04T00:00:00
Mission Phase Stop Time : 2001-10-14T00:00:00


IO 31 ENCOUNTER
---------------
Objectives: Tvashtar Plume and lava flow imaging and
compositional Mapping, Global Color Imaging, Temperature
maps of Io and its volcanoes. Real time science monitoring
of the inner Jovian magnetosphere and Io Torus, and North
Polar pass to study Io magnetic field North Polar pass to
study Io magnetic field. For Jupiter a Study of cloud
dynamics of hot spots, Feature track study of equatorial
waves, and Jupiter Occultation to yield electron density
profiles of Jovian ionosphere. Callisto/other target
objectives include Satellite Polarimetry and Sub-Jovian
Hemisphere Imaging.
Altitude: 200 km, Latitude: 77.5 degrees North

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 2001-08-06T04:58:48
Mission Phase Start Time : 2001-08-04T00:00:00
Mission Phase Stop Time : 2001-08-09T00:00:00


IO 32 ORBIT
---------------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 2001-10-14T00:00:00
Mission Phase Stop Time : 2002-01-15T00:00:00


IO 32 ENCOUNTER
---------------
Objectives: Io global and regional color maps, Regional and
targeted observations of hot spots, thermal emissions and
volcanic activity, SO2 distribution of the Chaac region and
temperature maps. Jupiter observations include white oval
monitoring, and Vortex regions at the poles, imaging of Gossimer
rings, and global sampling. Monitoring of the inner Jovian
magnetosphere and Io Torus with dayside sampling for
magnetospheres and transition region of the ion plasma. Other
targets include Europa polarimetry.
Altitude: 181 km, Latitude 78.6 degrees north.

Spacecraft Id : GO
Target Name : IO
Time of closest approach : 2001-10-16T01:22:53
Mission Phase Start Time : 2001-10-14T00:00:00
Mission Phase Stop Time : 2001-10-29T00:00:00


IO 33 ORBIT
---------------
Spacecraft Id : GO
Target Name : IO
Mission Phase Start Time : 2002-01-15T00:00:00
Mission Phase Stop Time : 2002-11-02T00:00:00


IO 33 ENCOUNTER
---------------
Objectives: Io includes global views, high resolution volcanic
centers (Kanehekili, Prometheus, Pillan, and Marduk). Thermal
mapping and Io gravity experiments. Jupiter observations include
the occultation, white oval, pole to pole thermal maps, and
global mapping. Magnetospheric interactions with Io - continuous
recording for 5 1/4 hours, Realtime science for 24 days around
closest approach, Crossing Ribbon Region of Io Torus. Other
targets include Europa polarimetry.
Altitude 100 km, Latitude 43.6 degrees north.


Spacecraft Id : GO
Target Name : IO
Time of closest approach : 2002-01-17T14:08:53
Mission Phase Start Time : 2002-01-15T00:00:00
Mission Phase Stop Time : 2002-01-20T00:00:00



INNER JUPITER PHASE
-------------------
During the final phase, the spacecraft samples the Jupiter
magnetic field down to two RJ, passes through the gossamer
rings, and performs a 914km flyby of Amalthea with a possible
nontargetted flyby of another minor satellite. The closest
approach geometry at Amalthea provides the best chance at
achieving high priority gravity data. After I33, the spacecraft
is on a ballistic trajectory for a Jupiter impact on the 35th
orbit. GMM operations end 28 February 2003 allowing sufficient
time for Amalthea data return. Fields and particles instruments
were left on and acquiring RTS data at the end of the mission.
The spacecraft will be periodically monitored until Jupiter
impact. A short sequence that allows for some RTS data to be
collected during the Jupiter impact orbit was placed on the
spacecraft before the end of mission.

Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 2002-11-02T00:00:00
Mission Phase Stop Time : 2003-09-21T00:00:00
Spacecraft Operations Type : ORBITER


AMALTHEA 34 ORBIT
---------------
Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 2002-11-02T00:00:00
Mission Phase Stop Time : 2003-09-21T00:00:00


AMALTHEA 34 ENCOUNTER
---------------
Objectives: Magnetosphere observations include realtime sampling
and Monitoring of the inner Jovian magnetosphere and Io Torus
with dayside sampling, and Transition region of the ion plasma.
The Amalthea orbit includes Jupiter impact on 2003-09-21.

Spacecraft Id : GO
Target Name : JUPITER
Time of closest approach : 2002-11-05T06:19:37
Mission Phase Start Time : 2002-11-02T00:00:00
Mission Phase Stop Time : 2002-11-08T00:00:00

JUPITER 35 ORBIT
---------------
Spacecraft Id : GO
Target Name : JUPITER
Mission Phase Start Time : 2003-09-21T00:00:00
Mission Phase Stop Time : 2003-09-21T19:07:00