ret Ly? o ae | We expect to have a photographic coverage - two cameras on each of these rifles to tell us something about what their actual velocity is - it's supposed to be in the vicinity of 1000' per second. And from the photographic coverage we expect to find out what happens after the fireball overtakes them. We hope that we can catch these projectiles that we're trying to catch to terminate their exposure to the fireball at the times we're trying to terminate them; and we hope that by inspection afterward, when we recover these projectiles, that we can determine whether or not we actually did catch then. We had some discussion last evening with representatives of J-6 and L-6 as to what difficulties we would run into in mounting these things on the tower, and I think by vertical firing we will eliminate any of their fears as to what the back-blast of these rifles may do to their device; and they were a little bit concerned abuut the drag of this totem pole on the tower, if we guy it to the tower. However, I think it can by guyed separately and eliminate anything of this sort. We expect to have about six men in the field from the first of March until probably eight or 10 days after Kickapoo, depending upon how long it takes us to get in to recover the metals and the magnetic tape records. I think we can have completed our construction requirements by the latter part of next week. Project 31.3 - Atlas - T. C. Looney - SC (Note: This project has since been cancelled.) When our ballistic missile re-enters the atmosphere there are two serious problems which are expected. One of them will be an erosion of the missile nose due to contact with particles in the atmosphere. The second one will be a general aerodynamic heating of the missile. In order to choose a suitable material for the missile skin, the designers would like to separate the two effects and study them independently. Ramo-Wooldridge, who have the primary design responsibility for the Atlas system, have approached the SC with the idea of our exposing some samples to the thermal from @ large yield weapon on this test. To get the desired flux, there are two ways you can do it: you can get far away from the blast and use mirrors to focus the heat on the material that you want to test, or the other way is to go in close. Project 5.9 @lready plans to use the mirrors. If we decide to do the project, we will go in close. There are advantages to mirrors and there are advantages to gcing close in, so every- thing here is based on whether or not we do the project. If we do the project, we will place the samples on Dog Island. This will put us some 7,000' away from GZ, with a 92 pei overpressure region. The theoretical predictions of the flux in this area should be something like 500 calories per sq cm per second. The thermal peak should arrive something like 2-3/4 seconds after zero time and the thermal will be down to 35% of its maximum value six seconds after zero time. Unfortunately, the shock wave arrives before the thermal does and this brings two unwanted items; namely, salt spray and sand. We will eliminate the sand from the