Jim Oberg emails:

ALERT: Tomorrow may be 'Eureka Day' -- the solution to the Columbia catastrophe.

At a one-hour briefing this morning by Columbia Accident Investigation Board (CAIB) member Scott Hubbard, the results of last week's air-gun-fired foam impact test were summarized.

Basically, the investigators were astonished at the amount of damage when a fiberglass panel was used as a target, and they expect a better-than-even chance that tomorrow, using an actual shuttle leading edge panel ('RCC'), they will break a hole in it.

The test will take place, weather permitting, in San Antonio. If the impact is as powerful as expected -- like getting hit with a 500-mph basketball is how Hubbard described it -- the 'missing link' in the causal chain that doomed Columbia Feb 1 may finally be on hand.

The experiment was surprising, Hubbard said, because the investigators (and NASA, which never even thought to perform such a test in the 25 years before this disaster) didn't appreciate how an entire mechanism of thermal protection hardware bolted together could flex and vibrate under the impact, suffering much more stress than just one piece of the system held firmly in place on a test stand. This 'missing link' has frustrated investigators for months.

Last week's test was using fiberglass, to verify the aiming of the air-gun. tomorrow's test will use an actual RCC panel from a flown shuttle. The RCC material is stiffer than fiberglass but four times weaker. If a piece breaks loose, it could be the explanation for the mystery orbiting object that was tracked falling away from the shuttle in orbit.

If a piece breaks loose tomorrow, 'pieces will fall INTO place' on the investigation.

The full presentation and dramatic photos are now on-line.

Further impact tests are planned through the end of June, but if the impact tomorrow shatters the leading edge panel, it will be THE most important day since the spaceship and crew were lost, more than four months ago.

So they may finally have the smoking gun. It's been pretty clear for weeks what happened. What remains unclear is what we do about it.

Well, that depends on what the meaning of "it" is. You have ably argued for transcending the present "Space Transportation System" rather than attempting incremental improvements to it. I would love to see a presidential speech reminescent of 25 May 61, with "facilitate the development of a passenger service to Low Earth Orbit capable of transporting 10,000 persons a year" replacing "land a man on the Moon and return him safely to Earth." But the environment we're in right now is shutting down model rocketry, for God's sake. It's a long way from point A to point B. What are the intermediate steps?

Short term, do away with that stupid CFC business WRT the insulation on the external fuel tank.

Long term -- heck, what Rand says.

Short term, we're not going to have another Columbia event, since all flights will be to the station where they will be able to be inspected prior to entry. All we really need to do is beef up life support on the station to handle the additional crew until another flight can come up. But as I've said repeatedly, the real issue is not crew loss, but continued attrition of a trivially small and shrinking orbiter fleet.

I'm saddened that this is starting to look like another case of "NASA syndrome" - so much for learning lessons.

When we discussed this at the British National SF Con at Easter (its a pretty serious one, the panel included the CEO of a private launch company and an ESA "novel propulsion systems" physicist) - the prediction was similar, with a view that future flights will have to be able to reach the station.