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Interplanetary travel for humans will require an equipment upgrade.
Some people think that we need a reliable interplanetary highway.
Flights to and from the Earth's Moon are not considered to be interplanetary travel.
it mean inside the planet
No, it means 'within the orbits of the planets' as in 'interplenetary travel' - travelling between planets.
Well Google says it means "In or between planets;"interplanetary travel"
The Mouse Factory - 1971 Interplanetary Travel 1-10 was released on:
USA: 29 March 1972
t has speachailpower