I mean, just taking the space shuttle up and back one time is hugely expensive.

我的意思是，仅仅是发射航天飞机一次再飞回的成本就已经是天价了。

youdao

The warping associated with the closed timelike curve could cause our slice to twist back on itself, making it impossible to divide all of space-time into distinct moments.

与封闭的时间型曲线相关的这种扭曲会导致我们的切分转回原处，不可能把所有的时空分成各自不同的时刻。

youdao

Where then, did our nearest neighbor in space come from, and what will the future bring? To answer these questions we must go very far back into time.

那么，我们这个最近的邻居来自何方，未来又将怎样？为了回答这些问题，我们必须回到遥远的过去。

youdao

Borman and Lovell proved that humans could survive in space for the time needed to get to the moon and back.

VOA: special.2009.07.01

They had proved that people could live and work in space for the time it would take to get to the moon and back.

VOA: special.2009.06.24

The other three parts move forward and back through time and space.

VOA: special.2010.01.10

Early results from Schaefer's study of the movements of gamma-ray bursts suggest that dark energy is different far out in space, and therefore way back in time.

NPR: New Clue to Universe's Darkest Mystery

Villa looked more lively early in the second half but, after Stiliyan Petrov drifted a clever cross-field ball into the heart of Pompey's back-pedalling defence, Young - with time and space to spare - could only drag a low shot well wide.

BBC: Aston Villa 0-0 Portsmouth

Kirkup said that the mobile space is changing so quickly, so now seems like a great time to step back and consider his next steps.

FORBES: Key Cell Phone Executives Leave Companies