Equatorial Low Earth Orbit (ELEO): An Orbital Incubator and Nursery

Recent research has shown that Equatorial Low Earth Orbit (ELEO) below 500 km has an exceptionally low space radiation environment that is ideal for long-term space settlements. The pressure vessel itself provides enough radiation shielding to enable decades of on-orbit habitation for an individual without exceeding radiation safety limits. My calculations using SPENVIS show that a minimum radiation "Incubator" region exists between 24° inclination at 350 km altitude, which drops linearly with increasing altitude to 0° inclination at 550 km altitude. Silicon-based spacecraft electronics inside a 1-mm thick aluminum hull would have a trapped particle dose rate ~4 orders-of-magnitude lower in the Incubator than in an ISS orbit. Single event upsets, however, will drop by only 2 orders-of-magnitude due to remaining galactic cosmic rays. With power supply modifications to mitigate the occasional latch-ups from galactic cosmic rays, plus replacement of short-lived components such as electrolytic capacitors, commercial off-the-shelf electronics should operate for decades. Even thin-film membrane spacecraft like BraneCraft, with only 10 microns of radiation shielding, could operate for many years without requiring radiation-hardened electronics. The ELEO Incubator is ideal for students and space startups wishing to flight test new space components, subsystems, and systems, potentially over decades of operation, without worrying about radiation degradation. It should be ideal for in-space computing centers; "the Cloud" above the clouds, and on-orbit manufacturing. Use of reusable first stages in the Falcon 9 launch vehicles has already enabled a 6 X reduction in delivery cost to LEO: 1,900 USD/kg today vs. ~ 10,000 USD/kg ten years ago. By 2028, fully reusable SpaceX Starships should deliver 100,000 to 150,000 kg to LEO for ~30 million USD: about $200/kg. This price should facilitate an explosion of new manned and unmanned applications: orbital assembly of large structures and habitats, construction of orbital factories for semiconductors and other high-value items, space hotels, and surprisingly, orbital villages with individual or multi-family homes. Over 140,000 people in the U.S. alone have a net worth over 50 million USD, and thousands of these might opt for an orbital home if it could be mass-produced and lofted for ~30 million USD. Humanity can begin colonizing ELEO in the coming decade, and small satellies could provide a rich infrastructure to support it.