What goes up , might not be a downer

Well, not as much of one.

What, exactly, makes a rocket fuel environmentally friendly?

I think, as with many headlines, adding an 'er' might be more accurate.

But any step in the right direction must be welcome.

At least it seems a tad more credible than some of the claims made by such as Virgin Galactic (and which have attracted a few eyebrow cranks of mine).

Exploration is necessary, so mitigating the consequences is the best option.