The U.S. Strategic Command has confirmed a spectacular fireball witnessed in Saskatchewan and Alberta on Friday night was the Antares rocket body burning up as it re-entered Earth's atmosphere.

Witnesses were initially baffled by the streak of bright light, which many thought was a plane crashing or a meteor.

Some described it as looking like metal melting or like fireworks in slow motion.

But the U.S. Strategic Command confirmed Sunday it was space junk burning up as it hurtled out of orbit and fell towards Earth.

"The 18th Space Control Squadron removed an Antares rocket body from the U.S. satellite catalog as a decayed object after it re-entered the atmosphere Nov. 24, 2017, over North America (vicinity Saskatchewan) at approximately [11:48 p.m. CST]," said chief of current operations Maj. Brian Maguire.

Thanks <a href="https://twitter.com/Dunlap_Obs?ref_src=twsrc%5Etfw">@Dunlap_Obs</a> -folks did indeed witness the reentry of <a href="https://twitter.com/OrbitalATK?ref_src=twsrc%5Etfw">@OrbitalATK</a>'s <a href="https://twitter.com/hashtag/Antares?src=hash&ref_src=twsrc%5Etfw">#Antares</a> rocket booster NORAD ID 2017-071B over <a href="https://twitter.com/hashtag/Saskatchewan?src=hash&ref_src=twsrc%5Etfw">#Saskatchewan</a> this AM- timing+location matches Space-Track prediction. <a href="https://twitter.com/CBCCanada?ref_src=twsrc%5Etfw">@CBCCanada</a> article: <a href="https://t.co/HuubCyjBve">https://t.co/HuubCyjBve</a> <a href="https://twitter.com/amsmeteors?ref_src=twsrc%5Etfw">@amsmeteors</a> page: <a href="https://t.co/rCQBcf031O">https://t.co/rCQBcf031O</a> <a href="https://t.co/LPUdMtJGGH">pic.twitter.com/LPUdMtJGGH</a> —@Astroguyz

Rocket makes mission possible

The Antares rocket body was launched on Nov. 12 on a resupply mission to the International Space Station.

It was used to propel the Cygnus CRS OA-8E ISS spacecraft into space and when its job was done, it fell into orbit along with thousands of pieces of space junk left over from other missions.

Because items can stay in orbit for decades, there are objects that have been circling the Earth since the 1960s.

According to The Aerospace Corporation, this was the predicted ground track of the Antares rocket body re-entry from space. (Aerospace.org) But scientists predicted the Antares would fall back to Earth around the time that it did.

Predicting the re-entry

Scott Young, the manager of the planetarium and science gallery at the Manitoba Museum in Winnipeg, said scientists use a model of the atmosphere to predict when the friction will be enough to know that the object will fall.

It's always possible that a few pieces might make it down onto the ground. - Scott Young, Manitoba Museum planetarium manager

Calculations can also predict where it will re-enter, but any uncertainty can change the location by hundreds or thousands of kilometres. Predictions for the Antares were that it would fall closer to Australia.

"There's probably a piece or two falling into the atmosphere every day. Most of that will happen over the ocean though, or a place where nobody will see them and most of them will be smaller than this particular piece," Young said.

The low Earth orbit, located 2,000 kilometres above Earth's surface, has the highest concentration of space debris. (NASA) "This one was a big one and it was over a well-populated area so that makes it fairly uncommon."

Burning up above Earth

Young said orbits will usually carry the discarded pieces anywhere between plus and minus 52-degrees latitude.

That means they can fall over most of the world's heavily populated areas, so the rockets are built with light materials that will disintegrate on re-entry.

"They don't want big heavy cast-iron pumps or things like that falling onto people's heads so they try to design them so that they will burn up safely," Young said.

"But it's always possible that a few pieces might make it down onto the ground."

U.S. Strategic Command said the effects of the atmosphere prevent the Space Control Squadron from accurately tracking any re-entries after initial contact with the atmosphere.

Manitoba Museum planetarium astronomer Scott Young says witnessing a rocket re-entry like the one over the Prairies on Friday could be a once in a lifetime event. (Trevor Brine/CBC) Young said safety is a consideration even before the objects fall back to Earth.

Tracking space junk

The Space Control Squadron is currently tracking more than 23,000 objects that are in orbit. They can be viewed on the Space-Track website, which is available to the public.

Young said it is crucial it knows where the objects are because it is possible they could collide with the astronauts at the International Space Station.

"[The squadron] basically have to watch for every little piece of spacecraft and discarded hatch cover and things like that," he said.

"Because even if it's a small piece, when it's moving at 30,000 or 40,000 km/h, if it hits you, it's going to be a bad day."

'Count yourself lucky'

When the objects eventually fall, the view from the Earth can be breathtaking.

Young said that for most people it is a once in a lifetime sight because bigger events like the Antares re-entry only happen about twice a year. He said the chances of the average person seeing it twice are relatively slim.

"It really does get spread around the globe so if you did see it you should count yourself lucky 'cause they're hard to see and they're spectacular," Young said.