Title of Paper: Design and Testing of the PICASSO-CENA Laser Transmitter Subsystem

Principal Author: Dr. Floyd Hovis

Abstract: In late 1997, Fibertek was funded by the Langley Research Center and Ball Aerospace and Technologies Corp. to build the Risk Reduction Laser (RRL), a prototype laser transmitter that would meet the performance requirements of a space-based aerosol monitoring lidar and thus reduce the risk for such a mission. The key laser requirements were 110 mJ per pulse at 532 nm and 1064 nm, 20 Hz operation, conductive cooling, and a lifetime of 2 billion shots. Approximately 10 months after initiation of the project, the RRL was delivered to Ball Aerospace and a test to demonstrate the required 2 billion shot lifetime was initiated. The success of the RRL contributed positively to the LaRC/BATC team winning the PICASSO-CENA ESSP mission. Since the initiation of the life test in 1998, the Risk Reduction Laser has accumulated 1.8 billion shots with an output energy fall-off of only about 5%.The RRL testing validated a number of important designs and processes that are being incorporated into the PICASSO-CENA flight laser. These include:

  1. Simplified contamination control procedures.
  2. A mechanically robust resonator design.
  3. Appropriate deratings for the pump laser diodes and intracavity laser fluences.
  4. The use of gray track resistant KTP doublers.

The optical design of the RRL has provided the basis for the flight laser for the PICASSO-CENA mission. The requirements for the flight laser that require additional design and test validation include:

  1. The hermetic laser canister seal design.
  2. Testing of the laser canister/optical bench assembly to random vibration levels >12 grms.
  3. The development of high-efficiency, space-qualified power converters.

Our presentation will discuss the details of the Risk Reduction Laser design and testing and give the status of the PICASSO-CENA flight laser design and test.