5. During Friendship 7’s three-orbit flight, NASA controllers saw indications that the capsule’s heat shield had come loose – which could be a fatal flaw for re-entry. They told Glenn not to jettison the craft’s retro-rocket pack, as an added precaution. Glenn ended up making a safe splashdown in the Atlantic Ocean, and it turned out that the apparent heat-shield problem was merely due to a sensor failure. Here you see Glenn’s capsule attached to a retrieval cable hanging down from a helicopter. The capsule released green dye into the water to help searchers find it from the air.
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