We propose to develop a novel thermal interface material (TIM) that is based on an array of vertical carbon nanotubes (CNTs) for high heat flux applications. For high precision, spaceborne lasers and other high power devices critical to NASA's Science Mission Directorate, heat flux levels are projected to reach 100 W/cm2. The state-of-the-art in space-compatible thermal interface materials (TIMs) is limited to a maximum achievable thermal conductance of approximately 5 W/cm2o
C. Preliminary testing of our innovative TIM approach has demonstrated thermal conductance values of 33 W/cm2o
C, a nearly seven-fold increase. For an incident heat flux of 100 W/cm2, this corresponds to a temperature drop of only 3o
C, compared with 20o
C for current technology. Thus, the use of our innovative CNT-based TIM will enable increased reliability, decreased size, and increased performance of spaceborne thermal management systems for the SMD.