Tag Archives: space satellite

Cluster of satellites in Earth's orbit.

Space junk is becoming a problem and we need to talk about it

When we think about junk, things like garbage bins or landfills come to mind — but there’s another junk problem, one that’s hard to see with the naked eye from the Earth. Space junk, researchers warn, is a growing problem, and if we don’t address it quickly, it may soon be too much to handle.

Satellites revolving around the earth. Image credits: ESA

There are a total of 6,542 satellites that are currently occupying Earth’s orbit, but only half of them are actually doing something. The other half are inactive — they’re simply junk. To make matters even more problematic, over 1,200 satellites were launched in 2020 — this marks a record, but generally speaking, we could expect more and more satellites to be plopped into orbit.

Now, imagine one day Earth’s orbit becomes overcrowded and two such large satellites hit each other. Both the satellites would get broken into smaller pieces that would further clash with other satellites and trigger a series of unstoppable collisions and a lot of junk pieces flying around. This has happened a few times already.

Due to these collisions, our planet’s orbit gets more and more cluttered with debris, to the extent that eventually, we will end up having no room to launch more rockets and satellites. Such a situation in which Earth’s orbit becomes completely unusable because of large amounts of space junk is referred to as Kessler syndrome — a phenomenon first envisioned by NASA scientist Donald J. Kessler in 1978.

Fortunately, we’re not at that stage yet. For now, space junk does not seem like a big problem but aerospace experts suggest that in the coming years, the number of satellite launches and space missions could increase dramatically, and this is likely to add more junk to space and make Earth’s orbit more crowded than ever. Simply put, if we don’t start taking action quickly, it will soon be too late.

What is space junk and why it’s dangerous?

Space junk is a generic term. Unusable satellite parts, rocket components, and debris of man-made machines in space are called “space junk”. Until now, NASA has tracked 27,000 such items that are aimlessly moving in Earth’s orbit. This orbital debris can move at a speed of 24,000 km/h (15,000 mph), and therefore any such fast-moving piece of junk can hit and destroy a functional satellite or a passing by rocket at any time.  

A graphical representation of debris in Earth’s orbit. Image credits: NASA

We’re already seeing some of this damage in action. In March 2021, the 18th Space Control Squadron (18SPCS), a space control unit under the US Space Force confirmed that a small debris piece named Object 48078 hit China’s Yunhai 1-02 satellite. According to Astrophysicist Jonathan McDowell, Object 48078 was a remnant of Zenet-2, a Russian rocket that was launched in the year 1996. McDowell further added that the “Yunhai 1-02 satellite broke up” after the collision. 

“Finding ways to remove at least some of all that space junk should be a top global priority.”

Donald Kessler, Retired NASA Scientist

However, such collisions due to space junk are still rare. Before the Yunhai 1-02 crash, the last collision reported was in 2009. Moreover, such collisions can be prevented by mission controllers by adjusting the position of a satellite. Every year many satellites are manoeuvered multiple times in order to avoid collision with space junk, even the International Space Station (ISS) has performed more than 20 junk avoidance maneuvers since its launch in 1998.

The space junk problem does not seem like a big issue for now but if not dealt with properly, it may lead to chaos in our planet’s orbit in the future — chaos that will be extremely difficult to address.

A small but growing problem

Before 2010, only around 100 satellites were launched every year but in the year 2020, for the first time, more than 1000 satellites were sent to space. The numbers continue to increase in 2021 as well because so far, 1400 new satellites have already been placed in orbit this year. 

Moreover, in the early days of space exploration, there used to be only a few agencies that would send satellites into space — like NASA, Roscosmos, and the European Space Agency. Nowadays, active private players like SpaceX and Blue Origin have created a boom in the aerospace industry and are launching more and more satellites. These companies are planning to launch mega-constellations (groups of satellites that cover large orbital area) in Earth’s orbit to provide wireless broadband internet services across the globe, in the coming years — an exciting project that is bound to help millions around the world, but which also poses new threats to the problem of space junk.

These mega-constellations would bring an unprecedented increase in the number of satellites revolving around Earth (a report suggests that the Earth’s orbit may have 100,000 satellites by 2030). With every launch, the amount of space junk will also increase making the orbit more congested. As a result, both the existing and new satellites will have to perform more collision avoidance maneuvers. 

Therefore, more fuel and resources would be spent on saving the satellites from space junk. Sooner or later, with an increasing number of space missions, the growing amounts of space junk might raise the frequency of outer space collisions and over the course of time, it could ultimately cause the Kessler syndrome.

Is it possible to free Earth’s orbit of space junk?

Cleaning up space junk is not as easy as it sounds. For starters, imposing a ban doesn’t seem like a promising idea.

Rockets are launched to explore space and collect information about other planets in our galaxy, whereas, man-made satellites are placed in Earth’s orbit in order to facilitate communication, navigation, military assistance, earth observation, weather forecast, mineral search, and many other activities that hold great importance for humans. Therefore, banning space missions and new satellite launches is obviously not a solution.

ELSA-d (End-of-Life Services by Astroscale-demonstration). Image credits: Astroscale/Wikimedia Commons

Cleaning our planet’s orbit is both an expensive and complicated process. However, researchers and space agencies are working on this and they keep coming up with new and interesting methods to remove space junk from Earth’s orbit.

Around 2012, a group of researchers working at EPFL (Swiss Federal Institute of Technology) came up with the idea of a special satellite (called CleanSpaceOne) that could attach itself to a targeted piece of space junk and drag the same back towards earth. The researchers proposed that during its journey to Earth, both the satellite and space junk would be burnt by the atmospheric heat.

This idea sounds promising, but it will also be costly, and bringing down satellites one at a time will be very time-consuming.

In 2016, the Japanese Aerospace Exploration Agency sent an electrodynamic tether in space that could direct space junk towards Earth’s atmosphere by using the planet’s magnetic field. A couple of years later, the Surrey Space Center in the UK launched the RemoveDEBRIS project in April 2018, this project was focused to encourage and demonstrate various space junk removal technologies. Under the RemoveDEBRIS initiative the effectiveness of methods involving net, harpoon, and drag sail for catching space junk was tested.

Researchers at Purdue University also developed a drag sail named Spinnaker3 in 2020. This powerful drag sail is an efficient and cost-effective way to deal with space junk as it does not require any fuel during its operation. Moreover, it can drag even rocket-sized space debris back to Earth’s atmosphere so that they get destroyed in peace. Spinnaker3 is expected to launch in November 2021 on a Firefly rocket.

A concept image of CleanSpaceOne chaser. Image credits: Lucpiguet/Wikimedia Commons

Astroscale, an orbital junk removal company from Japan, launched the ELSA-d (End-of-Life Services by Astroscale-demonstration) satellite in March 2021. This advanced debris removal system uses magnetic satellite catching technology to pick small inactive satellites from Earth’s orbit. ELSA-d successfully completed its first satellite capturing test on August 25, 2021, and it is now moving on to the next phases of its space junk removing process.  

The bottom line

As is generally the case, prevention is better than cure. In the case of space junk, it’s not yet a big problem — but by the time it becomes a big problem, it may be too big to handle efficiently, which is why it’s best to act as quickly as possible.

Aerospace experts are following this closely and if their research is supported, we’ll likely soon see effective waste-management strategies for space — and by the time we’re ready to go on our first interplanetary picnic, we’ll have a clean, green (hopefully), and beautiful orbital view.

Credit: Surrey Nanosats.

Watch this awesome giant net collect garbage in space

Where humans go, we leave trash — and that includes space, too. In fact, space junk is a growing problem that threatens to one day make it impossible to launch things beyond Earth’s atmosphere if we don’t do something about it. In a bid to clean our orbit, scientists have experimented with a device that harpoons a net and targets space debris to capture it. It apparently is as awesome as it sounds, seeing how the test was reportedly successful — with live video to back it up.

Credit: Surrey Nanosats.

Credit: Surrey Nanosats.

Since we began sending satellites into space in the late 1950s, we’ve been leaving behind trash with every launch. Every major world power has contributed to this growing space junk problem, with China in the lead most recently. In 2007, some Chinese general had the bright idea to actually test an anti-satellite missile in the field — that is, in Earth’s low-orbit. When China used this test to destroy their own Fengyun-1C weather satellite, the event was one of the worst single contributors to orbital debris, creating some 3,300 fragments.

NASA is monitoring some of the biggest pieces of junk out there, including approximately 20,000 objects as big or bigger than a baseball and 50,000 objects as big as a marble. Smaller pieces of debris, however, are virtually undetectable right now, but NASA estimates there are millions of objects that are 50 microns to 1 millimeter in diameter.

That might not seem like such a big deal but consider that these tiny debris travel at 17,500 miles per hour. At these velocities, even an object with a tiny mass can exert a powerful kinetic energy capable of significant damage upon impact.

Yes, the horrific scenes from Gravity are extremely plausible and astronauts stationed at the International Space Station are well aware of this when they’re sometimes ordered to man the escape pods. The waiting is not very pleasant at all, to say the least.

Space debris plot. Image credits NASA.

In order to clean Earth’s orbit of space junk, scientists have proposed all sorts of solutions, some wackier than others. The Japanese Kounotori 6 can tether space junk with electromagnetic forces. Astroscale, a Japanese startup, plans to launch a satellite called ELSA-1 that will track debris and stick to it with glue. Other ideas are even wilder, like using lasers to vaporize the surfaces of small junk pieces, forming miniature thrusters to force debris down towards the atmosphere. One recent project that the European Space Agency (ESA) is currently working on involves using powerful magnetic beams from a chaser satellite to nudge redundant satellites out of orbit.

RemoveDEBRIS, a project developed by British researchers at the University of Surrey, is another space janitorial project — and one of the most promising ones to boot. In June, the cube-shaped satellite was recently launched towards the ISS aboard a SpaceX Dragon capsule. It was later released from the station via the robotic arm Canadarm2.

On 16 September, the 100-kilogram satellite was actually tested in real-life conditions after it used a net to capture a deployed target simulating space debris. The object actually moved faster than expected, but the harpooned net was nevertheless able to catch up with it, as you can witness in the embedded footage below. The ensnared debris, along with the net itself, will eventually fall into the Earth’s atmosphere where it will burn up before it can do any damage to those in space.

This isn’t a crack on a car’s windshield, but 7-mm chip in diameter in one of the windows of the ISS’ Cupola — the dreamy vantage point which astronauts use to take amazing pictures. It was caused by “possibly a paint flake or small metal fragment no bigger than a few thousandths of a millimetre across,” ESA wrote. Credit: ESA.

The net consists of ultra-lightweight polyethylene Dyneema, typically used to make mountaineering ropes. Six weights attached to the net, which are actually small motors, helped it to expand to a full size of 5 m (16 feet) across. In the final version of the setup, the net would be connected to a chaser spacecraft with a tether. Once a piece of space debris is captured, the chaser would fire its engines and drag the junk into the planet’s atmosphere, where it would disintegrate. This time around, however, the tether was left out because it could have caused some unexpected complications. Specifically, engineers were worried that the satellite would rebound and hit the main RemoveDebris spacecraft, which still has some more experiments to run.

“We are absolutely delighted with the outcome of the net technology. While it might sound like a simple idea, the complexity of using a net in space to capture a piece of debris took many years of planning, engineering and coordination between the Surrey Space Centre, Airbus and our partners – but there is more work to be done. These are very exciting times for us all,” said Professor Guglielmo Aglietti, Director of the Surrey Space Centre.

For six years prior to launching the satellite, researchers have been testing parabolic flights in special drop towers and thermal vacuum chambers. Next, researchers plan on testing other technologies such as a vision-based navigation system that uses cameras and LiDaR technology to analyse and observe potential pieces of debris; the first harpoon capture technology used in orbit; and a drag-sail that will finally bring RemoveDEBRIS into the Earth’s atmosphere where it will be destroyed, bringing its mission to a close.