…could be up to five kilometers wide.

Mycroft Holmes, call your office.

[Update a few minutes later]

Speaking of the moon, Paul Spudis has some ideas about how to make space great again. I actually agree with most of it, except for this:

The Orion spacecraft and its SLS launch vehicle are currently in final stages of development, with initial test flights planned for 2018. We can use these existing systems to return to the Moon; indeed, as the remnants of the cancelled Constellation program, they are already optimized for cislunar missions. The only missing piece is a lander to put people on to the lunar surface. NASA’s Altair lander program was cancelled in 2011, but fortunately, a lander may be ready very soon. The United Launch Alliance has outlined a plan for a human-rated lander based around the venerable Centaur stage, using modified RL-10 engines. This vehicle is almost perfectly configured to return people to the Moon, as it is intended to be reusable and utilizes the LOX-hydrogen propellant that we will produce on the lunar surface.

The surest way to ensure that this doesn’t happen is to plan it around SLS/Orion, which will fly so rarely that we will make very little progress. He’s postulating the existence of a ULA lander, while ignoring the firmer plans for Vulcan ACES, which would be the natural way to carry out these mission (Orion might be usable in that scenario, but not SLS, and Dragon would probably be more cost effective). And as usual over there, the comments, particularly from “Bilgamesh,” are idiotic. And even more particularly the fantasy about flying SLS a dozen times a year.