importance to some of our programs. It goes against many of the assumptions that we have made, and we will have to re-evaluate quite a few of them on this basis. One of the important points that Jack (Welch) mentioned in his paper is that, if you do explode at very high altitudes, debris particles immediately get into this elipticalshaped region at the conjugate points. The altitude regime in which they are deposited is the 100- or 200- kilometer region, or perhaps slightly higher, and how this debris spreads and therefore affects the surrounding regions would depend critically on wind distribution and diffusion at these high altitudes. That's about all, ex- cept that I gather from Dr. Martell's comments that man's contamination is one of the problems which we are faced with. Even if the weapons testing itself decreases or stops, the use of nuclear reactors and nuclear pro- pulsion units is bound to increase, if not in the next 5 years, certainly in the next 30 years. We may be in the hollow part of the cycle right now, but the programs will increase, and this gives some urgency to our program. Dr. Tucker: I don't think I elaborated enough on Vela yesterday. anything like it is shaping up, when and if they sign it. the stations they are talking about. every second of the day. It is certain to be an expensive project if the treaty is It will take on the order of a billion dollars to implement This is a world-wide network; it is an every-minute-of-the-day network - A Vela network will give simultaneous recordings of all the parameters that we can think of as helpful in detecting tests. Because of the interaction, this is quite a number. ionosphere will be monitored far better than it is now. In other words, the Fluorescence fluctuations in the atmosphere will be far better measured than now, and the question will arise as to whether we want a few good measurements, or a lot of them with more or less continuous coverage. Continuous coverage is the type of thing we are bound to get with a Vela-type network, because we have to police the ionosphere, as well as underground, year in and year out. When we were preparing for this current Geneva conference, the objection was raised that we know we are going to fail to detect shots if they go out far enough and make the yield small enough. million miles and see a kiloton. You cannot go out 10 However, one of the most important psychological points of a treaty, and the one that started this test ban negotiation, was the contamination problem. It takes a tremendous amount of work to define what contamination to tolerate and so on, but at least the approach of determining nuclear tests on the basis of contamination has been suggested, and it does fit in very well with the political situation. This would mean sampling up to at least 600, 000 feet, and possibly up to Van Allen-belt altitude if some of the fission particles would be trapped there. In any event you would have to have an elaborate research program to find out everything you can possibly find about circulation and where the particles end up. It may be that radiochemi- cally you gain nothing by sampling continuously, but you have to proveit first; otherwise, in Vela you would start with the assumption that you must monitor almost continuously. the pure geophysics of the problem. You would be very much concerned with You would need to know exactly the circulation, residence time, trapping, charge interactions, effect on the ionosphere, and so on. Then you could do an adequate job of monitoring. all our projects a research program always starts out this way. In You cannot do your best job until you have done almost a pure research program. We will have balloons flying to measure gamma rays directly, because they will penetrate to balloon altitude, If you are flying balloons, maybe you will load each one with standard types of collectors. This kind of revolution has already occurred in seismic science. I would guess that the energy and input into seismology is up about 107 over what it was before these test talks started. You will get a reaction. We have already had some of that in the sense that we have made the radial-phase monitoring technique so 170