![]() ![]() The ISS orbits somewhat higher than 200 miles above the Earth's surface, roughly the distance from New York to Boston. ![]() NASA's Space Shuttle Endeavour orbits near the International Space Station in 2008. It's easier than ever to get to LEO, and that's triggered "a golden age of LEO innovation," said HawkEye 360 Chief Executive John Serafini, whose company helps government and military customers track radio signals to spot subjects like smugglers or lost boats. Companies based in Canada, Russia and China plan more. OneWeb envisions a whopping 48,000 satellites, though its near-term plans ran into a bankruptcy problem this year. Amazon's Project Kuiper plans 3,200 satellites. The SpaceX Starlink service, now in beta testing, has put 1,800 satellites into its constellation so far, on its way to more than 2,200. Every human who's been in space, aside from a few who made it to the moon's vicinity during NASA's Apollo missions, have hugged the earth in LEO. This is where you'll find the International Space Station along with satellites for weather forecasting, spying, television, imaging and, increasingly, satellite-based broadband. (NASA and the Federal Aviation Administration put the boundary at just 50 miles for anyone who gets that far up.) A bit higher than that, reaching up to about 1,243 miles (2,000 km) above the Earth's surface, is the most popular part of space, called low Earth orbit, or LEO. Space starts about 62 miles (100km) above us, though the boundary is somewhat arbitrary. For launches from Cape Canaveral in Florida, the rocket stage lands on a drone ship floating on the Atlantic hundreds of miles to the east. When SpaceX launches a rocket, it reserves some fuel to return the first stage of the rocket to Earth after its job getting a spacecraft into orbit is done. NASA considered launching moon missions from an equatorial site - though the fling factor was secondary to fuel considerations matching the moon's orbit. That's in part why US launch sites are located toward the southern parts of the country and why European spacecraft sometimes are launched from the Guiana Space Center in South America, just 5 degrees of latitude away from the equator. The Earth's rotation gives rockets a healthy eastward fling, and the closer to the equator a launch is, the bigger the fling. ![]()
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