‘Fire in space’ experiment to kick off aboard US cargo ship
- Nasa will ignite nine different materials aboard an unmanned spaceship
- Cygnus cargo ship left the ISS packed with 1.5 tons of garbage on Monday
- Ship and cargo are expected to burn upon reentry into Earth’s atmosphere
How does fire act in space?
Researchers will soon find out, by igniting nine different materials aboard an unmanned spaceship on its way to a fiery re-entry to Earth’s atmosphere, NASA said Monday.
The Cygnus cargo ship operated by the US company Orbital ATK left the International Space Station, packed with 1.5 tons of garbage, at 8:22 am (1322 GMT) on Monday.
Ultimately, the whole spaceship and its contents will burn up on re-entry to Earth’s atmosphere at 6:30 pm (2330 GMT) Sunday.
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The Orbital ATK’s Cygnus cargo craft (L) as seen from the Cupola module windows aboard the International Space Station on October 23, 2016 in a NASA photo obtained October 26, 2016
HOW FIRE BEHAVES IN SPACE
To help understand how flames burn in space, Nasa researchers have previously ignited a small drop of heptane and methanol (pictured)
Flames in space burn with a lower temperature, at a lower rate, and with less oxygen than in normal gravity.
This means that materials used to extinguish the fire must be present in higher concentrations.
The slow flow of air from the fans mixing the air in a spacecraft can make the flames burn even faster.
To help understand how flames burn in space, Nasa researchers have previously ignited a small drop of either heptane or methanol.
As this little sphere of fuel burns for about 20 seconds, it is engulfed by a spherically symmetric flame.
The droplet shrinks until either the flame extinguishes or the fuel runs out.
The latest experiment is aiming to test what would happen if flames appear on the ISS on a much larger scale.
But until then, the spaceship transforms into a test bed that aims to improve safety for astronauts living in space by helping experts better understand how fire behaves in microgravity.
‘A spacecraft fire is one of the greatest crew safety concerns for NASA and the international space exploration community,’ said project manager Gary Ruff, part of the team working on the experiment known as the Spacecraft Fire Experiment, or Saffire.
The nine samples of materials to be set ablaze include ‘flame retardant fabrics used for astronaut clothing, station Plexiglas window samples with edge variations and structures used for storage containers and silicone composites,’ said NASA.
Each sample is two by 11 inches (five by 28 centimeters), and is placed in a separate compartment for the fire study.
‘Saffire seeks to answer two questions,’ said principal investigator David Urban.
‘Will an upward spreading flame continue to grow or will microgravity limit the size?
‘Secondly, what fabrics and materials will catch fire and how will they burn?’
NASA said the first fire in the series of experiments would start about five hours after the Cygnus departed.
The goal is ‘to help investigators better understand flammability of these materials in a microgravity environment,’ said a statement by Orbital ATK.
The company said data will be downloaded from the spacecraft via telemetry.
Cygnus launched from Wallops Island, Virginia and arrived at the ISS on October 23, carrying 5,100 pounds (2,300 kilograms) of food, supplies and science experiments for the team of global astronauts living in orbit.
Orbital ATK and SpaceX have each been awarded NASA contracts worth more than one billion dollars to supply the space station.
This summer, Nasa released two videos of a large fire that was lit inside an unmanned cargo ship in space in a daring experiment.
The experiment, the first of three planned Nasa experiments on how big fires grow in space, was an important test for astronaut safety.
The space agency confirmed the fire had been lit on June 15th at 4:55pm ET.
The first of the two videos, which were posted on Nasa Glenn Research’s Twitter page, shows a test performed before the fire was lit, sending tendrils of smoke across the box to make sure that air was flowing through smoothly.
The second video shows the main experiment, where the fabric was ignited on one side by a hot wire on the material, and began to smolder and burn for approximately eight minutes.
Previous experiments in space were limited to the incineration of samples no bigger than an index card, said David Urban, lead researcher for the Spacecraft Fire Experiment, or Saffire.
‘We tried for years to find a vehicle and a circumstance where this would work and initially we’d get a ‘not on my spacecraft’ reaction,’ Urban said during a Nasa TV interview.
Nasa ultimately settled on using an Orbital ATK Cygnus cargo ship, which is designed to burn up in the atmosphere after it departs the space station.
The Cygnus, which departed the space station on Tuesday, was launched from Earth in March with more than 7,000 pounds (3,200 kg) of food, supplies and science experiments for the station, a research laboratory that flies about 250 miles (400 km) above the planet.
The second video shows the main experiment, where the fabric was ignited on one side by a hot wire on the material, and began to smolder and burn for approximately eight minutes
The cargo included Saffire, a module containing a 38-inch by 19-inch (97 cm by 49 cm) cotton-and-fiberglass material sample that was set on fire after Cygnus reached a safe distance from the station.
The experiment began with hot wires igniting the sample.
Air flowing through ducts fanned the fire, which lasted about eight minutes.
‘One of the big questions is how big will the flame get?’ Urban said.
Fire behaves differently outside of Earth’s atmosphere, so scientists want to test whether microgravity will limit flames and what materials will burn.
In February 1997, an oxygen-generating canister aboard the Russian Mir space station erupted into a searing flame, blocking the crew’s path to an emergency escape ship.
The crew fought the fire with foam extinguishers and water and it eventually burned itself out, leaving a thick residue of soot.
The Saffire experiment was the largest fire set in space since the accidental blaze on Mir.
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