EJECTION SYSTEM

The ejection mechanism has two sets of springs, one each for the hatch and the FFU. Both the hatch and FFU are restrained by a steel cable. While the design is primarily adapted from the ejection mechanism design of TUPEX-7, several modifications have been made to accommodate our bigger FFU. While the overall ejection mechanism has been extended by 30 mm, other components such as the Guide rails, the side, top, and bottom panels, etc have also been modified.

The FFU is retained within the ejection mechanism with a set of 1.5 mm steel cables. It is similar to the hatch retention system and is tensioned using a stack of spring washers so that when the springs are fully compressed, the cables will be loaded with the correct tension value. The FFU retention cables are tensioned with a force of 783.2 N. These cables are routed through a set of bearings and will be cut using three pyrocutters at T+71 seconds.
The FFU ejection mechanism will be manufactured out of Alumnium 7075 except for the cables, the bearings, and the screws which will be made out of steel.

The ejection system for the hatch has 4 compression springs which push on the plane surfaces of the hatch to eject it. The springs are designed to provide a total ejection force of about 62 N which results in a nominal hatch ejection velocity of 2.74 m/s.

The ejection system for the FFU is contained in a container composed of panles on the top, bottom, and the sides. The panels are held together by M3 counterbored screws. The FFU is held in place inside the container with the help of 8 guide rails which are lubricated to reduce friction. The springs used to eject the FFU are sized to provide an ejection force of around 83 N which would eject the FFU at a nominal velocity of 1.85 m/s