By Jupiter!




Mobile Suit Gundam: High Frontier

Life In The Universal Century

By Jupiter!

Other colonies in the asteroid belt and moons and rings of Jupiter are implied, but never shown. These are descendents of the Jupiter Energy Fleet launched in 2026 AD to collect hydrogen, helium³ and methane from Jovian atmosphere for the Earth’s tremendous energy demands. They are apparently self-sufficient and largely forgotten by the average citizen of the Earth Sphere.


In Z Gundam, charismatic Paptimus Scirocco captains the Jupitris, an asteroid-mining/refinery/factory ship two kilometers (1¼ miles) long that can literally “eat” a small asteroid and use its constituent elements to make a complete Mobile Suit within a 24-hour period.

Scirocco is sometimes called the “Man from Jupiter,” but it’s unclear as to whether it’s because he’s from the planet Jupiter or from the Jupitris, which is named for the planet.

The same orbital dynamics that apply to travel in the Earth Sphere also apply to the rest of the Solar system. Assuming a minimum-energy Hohmann type transfer orbit, such as we see used throughout the Earth Sphere, you must achieve a change in velocity (ΔV) of 6.6 kilometers per second to go from Earth orbit to Jupiter orbit.

In order to use a Hohmann orbit, you must start and finish with origin and destination precisely opposite the Sun. You can’t just boom out whenever you want, but must wait for the right geometry, otherwise your ΔV goes up and up to impossible values. For an Earth-to-Jupiter run, you get a launch window once each synodic period, the time it takes both planets to go around the Sun and come back to the same relative positions. For a Hohmann orbit, the two planets must be in opposition and the synodic period for such oppositions is 1.09 years. You can, of course, launch a ship from Jupiter to Earth at the same time you launch one from Earth to Jupiter, but you can only launch once every thirteen months.

(The synodic period for the asteroid 1 Ceres—and, by extension, for Axis and 3 Juno—is 1.28 years, little over 15 months. The ΔV is actually higher than for an Earth-to-Jupiter run, about 9.5 kilometers per second.)

The transit time itself works out to 2.7 years (32.4 months), so the ship that’s launched from Jupiter the same day that you send one out won’t get here until midway between your second and third outbound launch. For Scirocco’s Jupitris to arrive in the Earth Sphere on 29 April 0087, it must’ve been launched circa August or September 0084—just a few months after the Titans came to power.


Whatever the reason, the Jovian colonies remain remote and mysterious throughout the Saga and often clandestinely take sides in Terrestrial affairs, generally in support of totalitarian regimes. They supply advanced weaponry to the Titans and the Earth Federation while aiding and abetting Axis in the decade following the One Year War and give clandestine assistance to the Crossbone Vanguard forty years later, but their motives and objectives are never fully explained outside of Yoshiyuki Tomino’s six-volume manga side story Crossbone Gundam.

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Last Update: 01 January 2020

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