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March 18, 1965Reputable sourceWell documented

Alexei Leonov takes the first spacewalk

On the timeline · around March 18, 1965 · Alexei Leonov takes the first spacewalk19581960196219641966196819701972

What happened

Leonov floated outside Voskhod 2 for about 12 minutes; his suit ballooned so badly he had to bleed air to squeeze back inside.

Why it matters

Working outside a spacecraft — the capability every station and repair mission since has relied on.

Sources

Alexei Leonov takes the first spacewalk — A Timeline of Space Exploration · SourcedStory