Empirical Earth · Space, Satellites & the Edges of the Map

Satelloons — the balloon satellites that measured the Earth’s shape

The claim

“Satellites are just helium balloons — satelloons — and NASA buys all that helium to float them.”

What is measured

The story is half true and self-defeating: the balloons were real, they orbited rather than floated, and the survey that tracked them pinned the globe’s figure an order of magnitude better than any ground survey of the day.

What would show this is wrong

a balloon shown floating, buoyant, not orbiting, above ~55 km, or an account of GPS positioning in the mid-Pacific with no balloon, tower or cable in range. Neither exists.

Sources

  1. Project Echo and the “satelloon”. Echo 1 (1960, ~30 m) and Echo 2 (1964, ~41 m) were aluminised-Mylar balloon satellites orbiting near 1,600 km that passively reflected radio signals; the te link
  2. PAGEOS & satellite geodesy. PAGEOS (1966) was the first satellite launched specifically to measure the shape of the Earth; the Worldwide Satellite Triangulation Network fixed 46 globally dis link
  3. How high a balloon can float. High-altitude balloons typically reach 18–37 km; the all-time record is 53 km (Japan, 2002). By ~40 km the air is already below 0.3% of sea-level pressure, leav link
  4. Helium as a rocket pressurant. Helium pressurises and purges cryogenic propellant systems because it stays gaseous at liquid-oxygen/hydrogen temperatures and is chemically inert. NASA NTRS: link
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