NASA occasionally sends out space probes instead of humans because astronauts could not survive on some of the places that space probes are sent to.
NASA explores space by launching space rockets with famous astronauts in them
Astronauts aboard the space shuttle were primarily NASA astronauts, astronauts from Canada, Europe and other countries.
The last time a human has landed on the moon was in 1971. Since no NASA astronauts have landed on anything from that day on, astronauts are mostly carried by a space craft throughout their journey.
Nasa
I am not sure, ask NASA
NASA
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NASA in 1960 to know about the health of their astronauts on space mission.
because they don't have enough money
so astronauts don't get bored in space they will be active and will be moving around.
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