SAME in the Microgravity Science Glovebox
SAME photoelectric detector
SAME ionization detector
Spacecraft smoke detectors must detect different types
of smoke. For example, hydrocarbon fuels typically produce soot and plastics
produce droplets of recondensed polymer fragments. While paper and silicone
rubber produce smoke comprised of liquid droplets of recondensed pyrolysis
products. Each of these materials produces a different type of smoke,
with particles of various sizes and properties.
SAME will assess the size and distribution of smoke particles produced by different types of material found on spacecraft such as, Teflon, Kapton, cellulose and silicone rubber. SAME will evaluate the performance of the ionization smoke detectors (used on Space Shuttles), evaluate the performance of the photoelectric smoke detectors (used on the ISS) and collect data for which a numerical formula can be developed and used to predict smoke droplet growth and to evaluate alternative smoke detection devices on future spacecraft.
Fire is commonly detected by measuring changes
in the amount of airborne microscopic particles (one of the components
Smoke detectors currently in use on ISS and Space Shuttle are based on detectors used on Earth that detect different sizes of smoke particles.
SAME will measure the distribution of particle sizes in smoke from on-orbit combustion of several materials found in the spacecraft. Testing will also examine the effects of sample temperature, air flow and smoke residence time (near the source) on the particle size distribution of the smoke.
Results will allow an evaluation of the performance in microgravity of the two existing U.S. spacecraft smoke detector designs, in use on the Shuttle and ISS, and evaluate other fire detection devices.
Information from this experiment will improve the design requirements for and reliability of smoke detectors on future spacecraft.
The SAME experiment will provide technology for an advanced fire detector for future spacecraft that will be used for long duration missions. SAME will provide quantitative data on the sensitivity of these detectors to reduced gravity smokes that will allow evaluation of the adequacy of these existing technologies using relevant data. The current Fire Prevention, Detection, and Suppression (FPDS) program plan allows for the re-evaluation of future sensor technology, to allow new technology and capability to be utilized. The results from SAME are needed to provide the reduced gravity baseline data against which future detection technology developments can be evaluated.
The smoke detectors developed
from the results of SAME can also be useful in other extreme environments
on Earth, such as submarines or underwater laboratories. Accurate detection
of smoke in these environments can save lives.
Contacts at NASA Glenn Research
Project Manager: William Sheredy
Project Scientist: Dr. Gary Ruff
Principal Investigator: Dr. David Urban. NASA GRC