SIOUX FALLS, S.D. (KELO) — The line of light in the sky on Saturday and Sunday was SpaceX Starlink satellites that had just been launched.

There’s a chance those satellites will be visible just after sunset (Monday night), said Tom Durkin, the deputy director of the NASA South Dakota Space Grant Consortium. It’s an educational grant system that works with universities and K-12 schools in the state. The consortium is based in Rapid City.

“I wouldn’t be surprised if we could see them tonight before (they) making their way out (in space),” Durkin said.

The satellites are being launched by Elon Musk of SpaceX who has the satellites will be used to improve cell phone and internet connection in remote areas.

Durkin and others were at an observatory in Rapid City on Saturday night.

“I looked over and saw a light and it looked like a string of lights,” Durkin said. “There was less than playing card between them if you held that up to the sky.”

Because the satellites were so visible and so close together, Durkin said they must have been recently released.

“It was not quite three minutes they were visible. You could see them starting to separate,” Durkin said. “After about 2 1/2 minutes they disappeared into the shade of the earth which told me they are not very high up.”

The lights are created by sunlight reflected from the satellites.

Durkin saw the satellites again on Sunday night. “They were also in a straight line, they hadn’t veered off at all,” he said.

Satellites are released by an unmanned spacecraft called a SpaceX Dragon capsule. “Once they reach a certain point in the orbit, that’s where they are released. It’s just like dropping an egg,” he said.

Each satellite has its own thrust and as they move in orbit through space they will no longer be in a straight line,” he said.

The night sky is filled with natural objects but also satellites and the International Space Station.

Observers may be able to see the International Space Station just before sunrise or just after sunset as it continuously orbits the earth at about 17,500 mph.

NASA has a website to track the visibility of the International Space Stations. Starlink has a similar website.

You can also find out if you can see the satellites by using this tracking site.

SpaceX plans to launch thousands of satellites.

Like any other equipment, the satellites won’t last forever.

“There are so many satellites up there,” Durkin said. “As time goes on, more satellites will get launched in to orbit.”

More satellites increase the concern for the addition of more debris fields as satellites lose their orbit and burn out, Durkin said.

Because Starlink satellites have their own propulsion systems, the loss of orbit is different.

Starlink said on its website that if the propulsion system failed, the satellites will burn up in earth’s atmosphere within one to five years which is far less than older and larger satellites without propulsion systems.

Space debris creates its own orbit field that needs to be avoided, Durkin said.

There is no technology yet to clean up space, Durkin said. Part of the issue is that space is so vast and a piece of debris can be the size of a screw, he said.