Week 11: Sputnik

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By the late 1950s, the pieces from the last ten weeks — thrust, drag, gravity, stability, impulse — had matured enough for a rocket to do something no rocket had ever done: put something into orbit.

History

The launch of Sputnik 1 marked the true dawn of the space race, catching much of the world — including the United States — by surprise, and kicking off a period of rapid, competitive advancement in rocketry.

Forces

Staying in orbit, rather than falling back to Earth, requires enough sideways velocity that a rocket's curved fall matches the curve of the Earth itself — it's constantly falling, just never landing.

Math

v_orbit ≈ √(GM/r) (conceptual)

For context: low Earth orbit requires roughly 7.8 km/s — far beyond what any model rocket in this club will ever reach, but the same underlying idea.

Advances

Sergei Korolev led the Soviet program that developed the R-7 rocket used to launch Sputnik, working largely in secrecy under the Soviet system.

Key Date

Sputnik 1 launched on 4 October 1957.