Often considered the stuff of science fiction, sailing through space was suggested 400 years ago by astronomer Johannes Kepler who observed comet tails blown by the solar wind.

400年前，约翰·开普勒发现太阳风作用形成彗尾的现象，并由此提出星际航行的构想，但这常被认为是科幻小说里的内容。

youdao

It might be kind of fanciful to some, but on the other hand, space travel was considered science fiction not that many decades ago.

对于某些人，它可能只是种幻想，但换句话说，几十年前，太空旅行不也是被认为是科幻小说吗。

youdao

Science fiction that's just about people wandering around in space ships shooting each other with ray guns is very dull.

而那些津津乐道于人们在太空船里到处溜达还用射线枪互相射击的科幻作品都非常傻。

youdao

But the NASA rovers, Spirit and Opportunity, are the closest things we have to the space robots of science fiction.

VOA: special.2010.07.28

a vehicle that was popular in science fiction space travel stories.

VOA: special.2009.03.04

Having just played both Dead Space 3 and Tomb Raider, I may be feeling especially critical, but the science fiction space sets of Dead Space 3 are simply far more lush and immersive than anything I previewed in Star Trek.

FORBES: 'Star Trek: The Video Game' - Some Hands-On First Impressions

Traveling at light speed, which is something most space-faring science fiction tales suppose, is impossible.

FORBES: 'Prometheus' Screenwriter: Humans Will Never Reach Another Star, And Other Sobering Views On The Future

It helps booksellers define titles that are space-travel science fiction versus time-travel science fiction, cyberpunk versus steampunk, for instance.

FORBES: Charting the Sexiness of Fifty Shades of Grey