The objective of the Smoldering Combustion in Microgravity (SCM) experiment is to investigate the ignition and propagation of smoldering combustion in microgravity, in both quiescent and convective environments. Smoldering combustion is a nonflaming reaction that spreads through the interior of porous combustible materials. A burning cigarette is an excellent everyday example of smoldering combustion. Flown as part of USML-1 on STS-50