by Dennis M. Myers, 10/5/2019
- Low Earth orbit (LEO): geocentric orbits with altitudes from 160 to 2,000 km (100–1,240 miles).
- Medium Earth orbit (MEO): geocentric orbits ranging in altitude from 2,000 km (1,240 miles) to just below geosynchronous orbit at 35,786 kilometers (22,236 mi). Also known as an intermediate circular orbit. These are most commonly at 20,200 kilometers (12,600 mi), or 20,650 kilometers (12,830 mi), with an orbital period of 12 hours.
- Both geosynchronous orbit (GSO) and geostationary orbit (GEO) are orbits around Earth matching the Earth's sidereal rotation period. All geosynchronous and geostationary orbits have a semi-major axis of 42,164 km (26,199 mi). This works out to an altitude of 35,786 km (22,236 mi). All geostationary orbits are also geosynchronous, but not all geosynchronous orbits are geostationary. A geostationary orbit stays exactly above the equator, whereas a geosynchronous orbit may swing north and south to cover more of the Earth's surface. Both complete one full orbit of Earth per sidereal day (relative to the stars, not the Sun).
- High Earth orbit: geocentric orbits above the altitude of geosynchronous orbit 35,786 km (22,240 miles).
At the dawn of space exploration the old Van Allen radiation belts posed a health risk for early settlers. The belts weren't just a hazard, however. They also acted as a bit of a shield for people down on Earth. When the idea was first put forward to drain the radiation out of the lower belt, a lot of hyperbole on both sides prevented any real action for over a century.
Eventually, science and practicality won out, and the lower belt was drained of harmful radiation starting in late 2519. The outer belt remained intact, providing ample protection for those that still needed it. Advances in material sciences gave humanity a broad range of radiation filters and blockers, allowing orbital habitats to exist comfortably above the outer belt beyond 60,000 kilometers.
Originally orbital nomenclature divided orbits into three or four zones, depending on whatever Earthbound culture you were trying to talk to. With the single shield belt remaining, it became common to refer to those habitats under 13,000 kilometers, or below the belt, to be referred to as low orbit habitats, while above 60,000 kilometers was referred to as a high orbit.
The construction boom of the 24th and 25th centuries meant that lower orbits were well populated. The newer, more heavily radiation shielded structures in high orbit tended to be higher cost, and therefore a premium product. Higher orbit habitats also tended to be populated with more wealthy patrons, attracting top business leaders and the great thinkers of the day. By the late 2700's, much of the system's off-Earth wealth had accumulated in high Earth orbit.
By the time the Corporate Wars began with the treacherous Neptune Mining Ring Massacre on October 1st, 3201, many of the top corporations of the system had relocated their headquarters in high Earth orbit. Most Martian corporations and even the Lunar Sustainability Cooperative maintained a presence in the region. When Luna declared their neutrality at the outset of the war, it was only natural that those defending the rights of non-Earth dwellers should look to the corporations for leadership. By the end of the final battle, commonly known as Ringfall, in 3227, the Corporate Federation had been firmly established, giving clear guidance to the remnants of orbital humanity, and structure to the rest of the system.
Since then, while some few independant low Earth orbit habitats still long for the days of ground control, the future is forward. The future, is the Federation.
[ Back to List ]
Register and/or Log in to Comment