Last Saturday my scratch-built Double Shuttle had a double cato. The Double Shuttle consists of twin rocket gliders with a 24 mm motor in each half. They are joined together by a friction fit and separate when the ejection charge is ignited. On Saturday I had two E12-4's in the model and the temperature around launch time was about 18 Deg.F. I reported the cato's in a NAR mess report and I sent an email to Estes describing the event. Later Estes asked me for photo's, which I sent. Estes is going to send me a new pack of motors and a kit of my choice. I think that the model may be repairable and I have started rebuilding. I do not plan on using E-motors at these cold temperatures again. In the attached photos you can see the Double Shuttle on the pad. On ignition there was a loud pop and one cato did more damage than the other. The wings separated from one glider, but the other glider went to about 20 feet high. The other glider looked alright in the snow, but when I picked it up the wing had separated from the tube on one side and had damage.