The communications delays between Earth and Mars can be half an hour or more, so the people on the ground can't participate minute by minute in Mars surface activities.

Supplying fuel for a Mars expedition from the lunar surface is often suggested, but it's hard to make it pay off - Moon bases are expensive, and just buying more rockets to launch fuel from Earth is relatively cheap.

His finest hour lasted a minute and a half

His finest hour lasted a minute and a half.

We regard it as a certainty that the earth, enclosed between poles, is bounded by a spherical surface.

You can't make people laugh for more than half an hour and be consistent.