Assertion: solar energy's use | /r/HasProperty | proposed by grant logan
Facets:
value: in 1988
type: TEMPORAL
Source sentences:
text: In 1988 the use of an Earth-based laser to power an electric thruster for space propulsion was proposed by Grant Logan, with technical details worked out in 1989.
text: In 1988 the use of an Earth-based laser to power an electric thruster for space propulsion was proposed by Grant Logan, with technical details worked out in 1989.