Other practical motivations for interplanetary travel are more speculative, because our current technologies are not yet advanced enough to support test projects.
32.
Those calculations allowed 111 hours for interplanetary travel, 100 hours to explore Mars, and fourteen hours to perform engine overhaul and launch preparations.
33.
Together with Vladimir Vetchinkin and members of a rocketry club at the airforce academy, he founded the Society for Studies of Interplanetary Travel.
34.
The frame story is told in the first person, set in a future that has interplanetary travel and has recently seen an interplanetary war.
35.
However, the project was revised and edited, and by the time the patent was filed had become a large passenger craft for interplanetary travel.
36.
And what better way to further interplanetary travel than to tack on a Mars ship to the orbiting laboratory, giving both programs a plug?
37.
Supporters of Project Orion felt that it had potential for cheap interplanetary travel, but it lost political approval over concerns with fallout from its propulsion.
38.
Sardath, as a parting gift, gave Adam an upgraded version of his standard costume which allows for interplanetary travel as well as hard-light plasma weapons.
39.
The NASA chief began his career working on electric propulsion systems for human interplanetary travel at the agency's Lewis Research Center in Cleveland in 1962.
40.
The drag here is low enough that it could theoretically be overcome by radiation pressure on solar sails, a proposed propulsion system for interplanetary travel.
