LOSAT or Line Of Sight Anti- Tank is a kinetic kill weapon. It has no explosive warhead and relies exclusively on its vast kinetic energy to destroy the target.
This program began with the intent of firing it off a modified Bradley but when the Bradley ceased production a new launch platform was required. The choice was a modified version of the up-armored High Mobility Multipurpose Wheeled Vehicle or Humvee.
As attempts were under way to keep the program alive flight tests using existing motors and a revised guidance system were conducted off a Humvee.
The guidance for the LOSAT was interesting as the missle had only one sensor: an IR detector pointed backwards. This sensor was used to detect a laser pulse sent from the launch platform. The launcher had a sensor head (quite obvious on top of the vehicle) which tracked the target and the missile. The launcher would provide simple guidance information over the laser pulses.
Once the folding fins on the missile extended they locked into place and remained fixed. The only way of altering its course was via side mounted rocket motors. These were fired at carefully controlled times. The timing was crucial as the vehicle had a very high roll rate. In fact the only inertial sensor on the first version was there to determine the roll position. The guidance system used for these tests was a more usual IMU.
In this photo you can see the details of this flight test round. The fins are still unfolding and you can see that the motor is very low smoke. This was essential for the launcher to be able to track it during flight. For this flight a laser tracking system from Sandia Labs was being evaluated for use in the later flight test program.
In order to provide a sufficiently high reflection so the laser system could track, part of the missile was covered in Scotchlite reflective tape. As predicted by the thermodynamics guy, this peeled off within a mile or so and the laser tracker lost the missile.
One other visible feature are two dark bands around the nose. These are not paint but the Duroid radomes of the telemetry antennas. No sense conducting a flight test without getting some data back. Especially since these flights while guided by the IMU and guidance system received no updates from the launcher. They were just fired at the side of a mountain.
Duroid is good stuff and it holds up well to environments like this. Very high velocity and high heating. The only thing that would cause significant erosion is rain. A number of sled tests were performed to verify this many years ago.
This photo shows the view from the front. From this angle it doesn't look like the motor is low smoke. Most of this is from the paint and such in the launch tube vaporizing from the exhaust plume. You might also notice large chucks of white stuff flying around.
This version of the motor used an igniter that was part of the nozzle plug. Some bright boy thought it would be interesting to see where it went. So a structure of foam board and 2X4's was attached to the frame just behind the launcher. When the exhaust plume hit it, it disintegrated.
You might notice lots of cables coming out of the launcher. It was instrumented to verify the launch environments. Needless to say there was some concern for the safety of any crew inside. Which wasn't a problem here as this launch was controlled from the blockhouse.
I have always wondered at the sanity of placing four large missiles with UN 1.1 propellants (mass detonable) on top of a Humvee. It doesn't matter now as the program is dead.
But before it died, a series of flight tests were conducted using the new configuration. Besides the usual tank targets, fixed bunkers were also fired on. Video can be found on YouTube along with really awful sound effects.