Saw that. It's mostly just a rehash of the existing ideas, based on a new telescopic measurement of H in the atmosphere of Mars, and compared to other measurements of D abundance.

It's not even an improvement on Viking, which measured D and H simultaneously, and so avoided suggestions of systematic error between the two techniques.

The basic concept is fine. Mars had water early, and lost it somehow, somewhere - but also fairly early. Too early for it to be around to form an Ocean or floods later.

I might quibble that some of the water is stored as ice, and always has been, but that's a minor detail.

Nice to have someone else pushing the "dry" button!