Lava tubes are dangerous and often contain hidden surprises, some of them chemical in nature. (There are a few on Hawaii you can visit if you'd like to try it out for yourself - one I'd particularly recommend is at South Point, not far from the road to the Green Sands beach.)Consider the requirements for assessing even a small segment of one with a pressure suit. There would likely be falls, suit punctures, corrosives, hazardous situations, roof climbs, partial collapses, rock falls.It might be less risky to land/operate a tunneling machine. Where you could expose/inspect/seal/encase as a continuous process. Doesn't need to be many meters in diameter.
I find this development quite exciting to the point that for the first time since 1970's we have a valid reason to return to the Moon!
Just to give some scale to this. If the probable lava tube of possible length of 310 miles by 100 meters diameter was excavated out for the full length to that diameter then the volume that would represent is 3.9Billion cubic meters. If you assigned a person 1000m^3 that would be space for 3.9million people. It would be more space than most urban dwellers have on Earth.
But lava tubes are found only in the maria, which are mostly concentrated near the equator and at low latitudes. One of the biggest drawbacks to cave living on the Moon is that we don’t have any near the poles. At the poles there is near-constant sunlight, along with deposits of water ice—valuable resources essential for human habitation. Yet enjoying the advantages of underground living doesn’t require caves. It is possible to place a habitat at the bottom of a deep crater, lay out an airlock, access tunnels, electrical cables and cooling lines, and then backfill (cover over) the crater with lunar regolith (soil) using a bulldozer. This simple construction technique provides all the thermal and protection advantages of cave dwelling, without restricting the outpost location to a less than optimum locality.The advantages of cave life seem so attractive that every time a new lunar lava tube discovery is made, there is a call to use them to live on the Moon or other planets (most recently shown in the current “Mars” television mini-series). But people live where they can make their livelihoods and on the Moon, that “pay dirt” is at the poles, in the form of water and electrical power. The Willie Sutton principle still prevails.
I believe the lava tubes, like at Marius Hills, definitely should be investigated.How could a probe explore a skylight like one of these?