NASA's commercial partner Orbital ATK will launch its Cygnus cargo spacecraft, filled with supplies and science experiments, into lower Earth orbit on Tuesday. There, the spacecraft will dock with the ISS and replenish the crew with food, water, and other important inventory. But the spacecraft's mission won't be quite done once the astronauts unload all the supplies on board Cygnus. The capsule will be loaded up with trash from the station and separate from the ISS — and then NASA will light the capsule on fire.
It's all part of a NASA experiment called Saffire. It involves igniting a flammable material inside the Cygnus spacecraft, to better understand how potential fires can spread across a vehicle in space. Though NASA has been flying spacecraft for decades, the agency has very little knowledge of how fires behave in microgravity, the space agency claims. NASA has purposefully set fire to materials in space for research, but those samples have all been fairly small — less than four inches in length and width. This blaze aboard the Cygnus will be much larger; a material more than three feet long and one foot wide (1 meter long and .4 meters wide) will go up in flames inside the capsule.
A material more than three feet long and one foot wide will go up in flames inside the capsule
The heated experiment won't pose any danger to the astronauts on the station, according to NASA. The Cygnus will be about four hours away from the ISS when Saffire gets underway, said Gary Ruff, an aerospace engineer at NASA's Glenn Research Center, during a press conference. The craft will also be in a much lower orbit than the station. "The crew won’t really have any interaction or knowledge about what’s going on while they’re doing [the experiment]," Ruff said.
But NASA will know how the fire is burning in the spacecraft's gut, thanks to multiple instruments on board the Cygnus. Sensors will measure the amount of oxygen and carbon dioxide inside the capsule, as well as the overall temperature, according to NASA. Two cameras will also provide a direct view of the inferno, which is slated to burn for about 15 to 20 minutes, according to Ruff. The space agency will then spend the next week downloading all the data from the sensors and cameras, which will be used to help NASA come up with better methods for detecting fires in space, as well as preventing them and stopping their spread.
As for the Cygnus, the spacecraft will escape one fire only to be caught in another. Once NASA has all the information it needs, the capsule will get out of orbit and re-enter Earth's atmosphere. That's when the entire thing burns up for good.
Getting burned isn't all that Cygnus will do, though. The craft will deliver four additional science experiments when it first docks with the ISS; those include a second 3D printer for the station and five special adhesive strips known as Gecko Grippers, which mimic the unique sticking abilities of geckos here on Earth. The Cygnus will also be carrying an instrument called Meteor, that will be used to figure out the composition of meteors entering Earth's atmosphere. This is actually the third attempt to send Meteor into space; the first version of the instrument was destroyed when Orbital's Antares rocket exploded on the launch pad in October of 2014. The second instrument was then lost when SpaceX's Falcon 9 rocket disintegrated during a launch in June 2015.
Cygnus will deliver four additional science experiments when it first docks with the ISS
Tuesday's launch also marks the second time Orbital will resupply the ISS using an Atlas V rocket —the premier vehicle of the United Launch Alliance. Orbital has been using the Atlas to launch its spacecraft into orbit, while the company replaces the engines in its own Antares rocket. Orbital decided to update the Antares following the 2014 explosion, a process that has taken a year and a half. However, the company will get back to using its own rockets soon. Orbital's next resupply mission to the ISS, scheduled for May 31st, will mark the first flight of the updated Antares rocket.
Next week's launch is scheduled to take off at 11PM ET on Tuesday, March 22nd from Cape Canaveral, Florida. Check back here to watch the launch live.
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