Galileo Ganymede 2 Flyby Navigation Results

On September 6, 1996, the Galileo probe flew by Ganymede at a distance of 260.2 km. This is the closest flyby of any of Jupiter's moons during Galileo's two-year primary mission. Not only did this close flyby enable Galileo to collect excellent science data of the solar system's largest moon, but it provided a planned gravity assist to change Galileo's orbit for the next encounter on November 4, 1996. Below are the times and navigation results of the Ganymede 2 flyby.

Acronyms

C/A  - Closest Approach
ERT  - Earth Receive Time
JMED - Jupiter Mean Equator of Date
JOI  - Jupiter Orbit Insertion
OD   - Orbit Determination
OTM  - Orbital Trim Maneuver
PM   - Propellant Margin
S/C  - Spacecraft
SCET - Spacecraft Event Time

Ganymede 2 Flyby

C/A Time (SCET): 9/6 18:59:34.3 UTC, 9/6 11:59:34.3 PDT, 9/6 14:59:34.3 EDT
C/A Time (ERT): 9/6 19:38:34.4 UTC, 9/6 12:38:34.4 PDT, 9/6 15:38:34.4 EDT
Radius: 2894.2 km (1798.3 miles)
Altitude: 260.2 km (161.7 miles)
Latitude (GTED): 79.47 deg
Speed at C/A: 7.961 km/s (17,809 mph)
Approach Speed: 7.520 km/s (16,821 mph)

Speed Increase to C/A: 441 m/s (987 mph)

Ganymede 2 Gravity Assist

Total Gravity-Assist Delta-V: 856.3 m/s (1,916 mph)
Orbiter Speed Change: -99.4 m/s (-222 mph)
Equivalent S/C Propellant:

33% larger than JOI
7.7 times Delta-V remaining
55% of total Delta-V at launch

Before Flyby After Flyby Orbiter Speed 14.510 km/s (32,460 mph) 14.411 km/s (32,240 mph) Orbit Period 71.6 days 60.2 days Orbit Inclination (JMED) 4.35 deg 0.54 deg

Ganymede 2 Flyby Navigation

Target Achieved Miss Time (9/6, UTC/SCET) 18:59:39.9 18:59:34.3 -4.7 sec Altitude 262.2 km 260.2 km -2.0 km Latitude (GTED) 79.52 deg 79.47 deg -0.05 deg
(Courtesy Galileo Navigation Team)

Ganymede 2 Quick-Look Orbit Facts

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