Google Gravity Balloon |work| May 2026

The "Gravity Balloon" (a nickname derived from its buoyancy-based altitude control) was not a balloon in the party sense, but a operating in the stratosphere—a realm colder, drier, and more violent than most aircraft ever encounter. 2. The Physics of Floating Against Gravity To understand Loon, one must first understand the stratosphere (10 km to 50 km altitude). Below 10 km, weather dominates: wind shear, turbulence, precipitation. Above 20 km, the atmosphere is stable, with predictable zonal (east-west) wind bands. However, at 20 km, air density is only 7% of sea level.

Project Loon was born from a counterintuitive question: What if the cell tower floated? google gravity balloon

[ V = \frac{m_{air}}{\rho_{strat}} \approx \frac{30 \text{ kg}}{0.088 \text{ kg/m}^3} \approx 340 \text{ m}^3 ] The "Gravity Balloon" (a nickname derived from its

1. Introduction: The 95% Problem In 2011, Google X (now X Development) proposed a radical solution to a persistent economic reality: while satellites offered global coverage but were expensive and high-latency, and cell towers offered high bandwidth but were geographically limited, nearly 95% of the world’s population lived within range of a cellular signal—yet only half were connected. The problem wasn't coverage; it was economic viability in rural and remote regions. Below 10 km, weather dominates: wind shear, turbulence,

That’s a sphere ~8.7 meters in diameter—roughly a tennis court’s width. The final Loon balloons used a pumpkin-shaped lenticular envelope to reduce drag and manage stress. Traditional weather balloons are zero-pressure : they have an open duct at the bottom. As gas expands (daytime heating, rising altitude), excess vents out. At night, the balloon contracts and descends. This is fine for a 2-hour radiosonde flight but disastrous for a 100-day mission.