Minggu, 01 November 2020

Canadian satellites to help combat threat of collisions in Earth orbit - CBC.ca

Humans produce a lot of garbage here on Earth. It turns out we produce a lot of it in space, too.

There are an estimated 20,000-plus satellites and pieces of debris orbiting Earth. These satellites can be operational or defunct, and the debris is left over from the thousands of spent rocket stages or the result of collisions that have produced smaller pieces.

It's these collisions that are of particular concern, especially with more and more private companies and countries launching satellites into space.

While this may not sound like something that poses a threat to our daily life, the fact is that it could disrupt it in many ways, with the two main threats being to the lives of astronauts in space, as well as the threat to the satellites we depend on each day.

One Canadian company wants to decrease the chance of these collisions.

On Tuesday, Montreal-based NorthStar Earth & Space announced that in 2022 it plans to launch the first commercial constellation — a collection of satellites — to reduce the threat of the collision of objects in space. Thales Alenia Space will build the first three satellites in the Skylark constellation with Seattle's LeoStella, overseeing the final assembly.

This illustration shows how NorthStar's constellation will track satellites in Earth orbit. (NorthStar Earth & Space)

"People tend to forget that today, we actually depend on spaceflight. When you look at your smartphone, 40 per cent of the apps they have, they rely to some degree on data from space — let it be the weather forecast, let it be the navigation app that relies on GPS satellites, TV broadcasting and sometimes the phone connection itself" said Holger Krag, head of the European Space Agency's Space Debris Office in Darmstadt, Germany. 

"They all go via satellite. So if we don't have satellites, we will quickly realize what is missing."

According to the European Space Agency (ESA), over the past 20 years, there have been roughly 12 accidental breakups annually in low-Earth orbit. 

While current technology relies mostly on ground-based telescopes to track potentially dangerous space debris and satellites, NorthStar will have satellites equipped with telescopes in orbit around Earth, bringing the accuracy of tracking within metres. 

"We've got the International Space Station up there. We've got astronauts going back and forth. We've got stuff flying around from a bunch of satellites and constellations," said Stewart Bain, NorthStar's CEO. "You want to make sure you know where things are with metre precision, not kilometre precision."

Close calls

On Oct. 16, a dead Russian satellite and a spent Chinese rocket stage missed each other by a mere 11 metres, extremely close in Earth-orbit terms. 

In January, there was a similar incident.

And in September, the International Space Station was forced to conduct an "avoidance manoeuvre" in order to avert a collision with an unknown piece of space debris.

They are all examples of just how frequent these potential collisions are.

Though satellites are tracked by countries, such as the U.S. Air Force's Combined Space Operations Center, there are private companies, such as LeoLabs in Menlo Park, Calif., that also monitor the busy space around Earth. However, most rely on telescopes here on Earth.

The problem with that is, ground-based telescopes aren't as accurate and can be taken out of service due to inclement weather. 

That's the benefit of having satellites in space directly monitoring objects, Bain said.

ESA's Krag said that NorthStar's plan is a good step in getting more accurate information as to how close satellites might be to one another.

"As soon as the data comes in, it's accurate. It's more accurate in particular than anything else we have," he said. "In space, you can observe all the time when you have an optical sensor because you're not dependent on weather conditions. You can basically position yourself in a way that you always have the objects in sunlight.… I think that's a very promising solution."

However, he said that there are also challenges, such as how fast the object will pass in the tracking satellite's line of sight, so the sensor will need to be very fast. 

Krag also noted while there's a worrying trend that there is more debris being created by collisions or other means, the good news is that more rockets are being better disposed of and more satellites are being put into orbits where they can re-enter Earth's atmosphere and break up as they descend. 

Still, with a new space economy, Bain said that it's becoming increasingly important to ensure that our satellites are protected, even if it's not something most people think about on a daily basis. 

"We rely on space to monitor our crops, to monitor food production, to monitor the quality of water, to monitor the weather, telecoms, everything," Bain said. "We rely on space, but we take it for granted."

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2020-11-01 09:00:00Z
CBMiQWh0dHBzOi8vd3d3LmNiYy5jYS9uZXdzL3RlY2hub2xvZ3kvbm9ydGhzdGFyLXNhdGVsbGl0ZXMtMS41NzgyMDg10gEgaHR0cHM6Ly93d3cuY2JjLmNhL2FtcC8xLjU3ODIwODU
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