Can a federal agency responsible for the safety of a technology adequately assess and regulate its operations while at the same time promoting its success in the marketplace? The question, which may now be raised in the wake of the NASA/shuttle catastrophe, eventually became the focus of another presidential commission, the one that examined the 1979 accident at Three Mile Island. There appear to be a number of significant parallels in the course of both investigations, and in the lessons to be learned.

Both cases involved a complex technology with significant risk potential but an outstanding public safety record. Both involved government agencies associated with the development of such technology, its oversight and its commercial success.

The initial reaction of NASA following the Challenger accident and of the Nuclear Regulatory Commission following the TMI accident was to have their own officials and contractors carry out internal investigations.

But in both cases, public concern quickly led to the formation of special presidential commissions. In both cases, such commissions were instructed to focus on the particular accident rather than the broader implications, and to come up with reports and recommendations in a relatively short time.

At the NRC and the TMI commission, the initial reaction was that the nuclear accident was the result of equipment malfunction compounded by human error, a series of "incredible" events that could not have been anticipated but that could be corrected in the future without seriously affecting the future of nuclear power.

At NASA, the initial reaction was similar: the Challenger accident must have been a malfunction that could not have been anticipated, one that probably could be corrected in time to resume flights within months.

At the TMI commission, views as to the implications of the accident soon changed. Some witnesses were found to be telling less than the whole truth. Contractor documents were discovered that showed clear, specific warnings of such an accident years before; that just such an accident had already occurred in another, similar facility; that such warnings either did not reach the top or had been dismissed.

It's still not certain what caused the Challenger accident, but early phases of the investigation have already shown that safety concerns expressed on one level may not have reached another; that warnings have been overlooked or rejected.

And it's still not certain how far the Challenger commission can pursue such investigatory leads. The TMI Commission had a professional staff of 80 or 90 people, including skilled technical consultants. The Challenger commission, at least for now, has a handful of attorneys. More significantly, perhaps, the TMI commission requested and received from Congress the power to subpoena documents and to take testimony under oath, and, according to participants, used such authority repeatedly to compel witnesses to testify and to produce key files.

And it remains to be seen whether the Challenger commission will go beyond its apparently restrictive mandate to examine broader issues. The TMI commission critically examined the question of whether the NRC should be nurturing or promoting the expanded commercial application of nuclear power while bearing responsibility for operational safety. Should NASA, with similar safety responsibilities, be out in the marketplace actively selling time and space on future shuttle flights?