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| Glenn Leads Spacecraft Fire Safety Tech
Development Effort |
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Space travel poses many risks for astronauts
since they are confined to the spacecraft during both normal and emergency
operation. They must be able to quickly react to hazardous situations
while maintaining their health and safety. Fire is especially dangerous
inside a spacecraft or planetary habitat because it can be difficult
to detect and extinguish a fire in microgravity.
To maintain astronaut safety during increasingly difficult exploration
missions, NASA’s Glenn Research Center is leading technology
development for spacecraft fire safety through the Fire Prevention,
Detection and Suppression Project. Glenn’s extensive background
in microgravity research and support from universities is helping
to improve fire safety for the Orion crew exploration vehicle. |
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| Prevention |
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Image: Allied Signal/Honeywell
light-scattering smoke detector used in the ISS. |
To prevent fires from occurring, the flammability of materials inside
the spacecraft must be tested at the oxygen levels and atmospheric
pressure in which they will be used. These tests indicate the flammability
on Earth, but they do not reveal how the material will burn in low
gravity. As new lightweight materials for exploration missions are
developed, they will also need to be analyzed for flammability.
To improve the methods to assess material flammability and fire prevention,
Glenn will accomplish the following:
- Develop tests that can be performed on Earth to analyze the
flammability of materials in low gravity
- Assess material flammability in exploration vehicles and habitats
in low and partial gravity
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| Detection |
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Image: Portable CO2
fire extinguisher used on the U.S. modules of the ISS. |
If a fire starts in space, it is vital that the astronauts detect
it immediately. The smoke detectors used on the International Space
Station and Space Shuttle are generally not desirable for use on future
exploration missions. Standard smoke detectors are designed to detect
smoke particles that form on Earth. Experiments conducted in microgravity
have shown that the particle size formed in low gravity is larger
than those produced on Earth.
Additionally, smoke detectors on Shuttle and Station have been susceptible
to false alarms from the dust particles. Every false alarm must be
investigated by the crew, which wastes valuable time and decreases
their confidence in the fire detection system. When pre-fire events
have occurred in space, the crew usually detects the situation with
their noses before the detectors notify them.
To solve the above problems, Glenn is creating advanced detection
systems that combine particle and gas-sensing capabilities that respond
quickly to fires and better differentiate between a signal from a
fire and one from another source. Glenn is also developing a data
bank of fire signatures (signals that trigger the sensor to respond
to a fire) that will also help the new detectors reduce false alarms. |
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| Suppression |
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Image: A burning sample
in the Upward Flame Propagation test (Test 1). |
Once a fire is detected, the astronauts must act fast to put it out.
In the Space Shuttle, the crew can use a Halon fire extinguisher.
In the Space Station, a portable CO2 extinguisher can be used in the
U.S. modules while the Russian side has a water-based foam device.
The requirements for fire extinguishers for Orion require a re-evaluation
of fire suppression technologies. Compared to the Space Station, Orion
is very small. If Orion’s crew used a CO2 extinguisher, it would
dilute the oxygen level inside the vehicle so much that the atmosphere
would become hazardous to their health. The use of Halon is not desired
because it cannot be removed from the cabin atmosphere and it can
produce harmful products when it interacts with the fire. Foam extinguishers
may be suitable, but would be more difficult to clean-up.
Glenn is currently working to establish the unique requirements for
new fire extinguishers for Orion. Glenn is also testing various types
of suppressants and evaluating how they will be dispersed in low gravity.
Fire safety is a key issue for future exploration missions. Glenn’s
current efforts in leading the Fire Prevention, Detection and Suppression
Project will help ensure the health and safety of the astronauts. |
Contact at NASA Glenn Research Center
Acting Chief, Advanced
Capabilities Project Office: John
K. Lytle
Space Flight Systems Directorate
/ Advanced Flight Projects Office
216-433-3213
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