| Definition | a spacecraft propulsion system that uses electrically accelerated ions. |
| OED requirements | antedating 1947 |
| Earliest cite | Jack Williamson, The Equalizer |
| Comment | Mike Christie submitted a 1947 cite from Jack Williamson's "The Equalizer".
Earliest cite in the OED: 1958. |
| Last modified | 6 July, 2008 |
click here for more information about the citation list
| 1962 C. Smith Ballad of Lost C'mell in T. Shippey Oxf. Bk. Sci. Fiction (1992) 303 | Though men had had nuclear rockets since the beginning of consecutive history, they had used chemical rockets to load the interplanetary ion-drive and nuclear-drive vehicles or to assemble the photonic sail-ships for interstellar cruises. |
| 1968 S. E. Whitfield in S. E. Whitfield & G. Roddenberry Making of ‘Star Trek’ ii. ii. 192 | Discussions‥had already ruled out atomic power as inefficient and inadequate for achieving hyper-light speeds. Ion drive was ruled out for the same reasons. |
| 1970 P. Anderson Tau Zero (1973) 25 | The ion drive came to life. No man could have gone behind its thick shielding to watch it and survived. |
| 2004 P. F. Hamilton Pandora's Star vii. 173 | Once they'd fallen a kilometre from the gateway, their ion drives came on, pushing them into high-inclination orbits which would provide coverage of the planet's whole surface. |
| 2006 N. Asher Polity Agent i. 27 | The H-shaped craft drew to a sudden halt above them, then began to descend.‥One strut of the H contained the ion drive, and possibly its controlling AI—though such ships were usually telefactored—and crew quarters if necessary. |