What’s common between the delayed Chandrayaan-3 launch and a damaged Florida home? Space junk

There are close to 6,000 tons of materials in low Earth orbit.

A photo of a 15 year-old piece of space junk captured by Astroscale’s ADRAS-J mission. (X/@astroscale_HQ)

Why is space junk dangerous?

According to the European Space Agency, more than 60 years of space activities have resulted in some 56,450 tracked objects in orbit, of which about 28,160 remain in space and are regularly tracked by the US Space Surveillance Network (USSSN) and maintained in their catalogue. The USSSN catalogue covers objects larger than about 5-10 cm present in LEO and 30 cm to 1 m at geostationary (GEO) altitudes.

As per NASA, most of this debris moves very fast, almost reaching speeds of 29,000 kilometres per hour. To give perspective, a bullet travels nine times slower. Add to it the volume of debris, and that’s a glaring risk to the safety of people and property in space and on Earth.

Even as a million more satellites are predicted to head to LEO in the coming years, questions persist about the environmental impacts of burning up satellites in Earth’s atmosphere. A bombshell study last October found unexpectedly high amounts of vaporised metals polluting Earth’s stratosphere, while another suggested that debris from burning satellites could be messing with our planet’s magnetic field.

But a collision of debris into another body in space in not where it stops. The hit body could break into thousands of fragments, which could then collide with other satellites and payloads, triggering an infinite cycle. Such a possibility, known as Kessler Syndrome and depicted in the film Gravity, could put an end to services such as GPS and satellite imaging.

On 21 January 2001, a Delta 2 third stage, known as a PAM-D (Payload Assist Module – Delta), reentered the atmosphere over the Middle East. (Credit: Space Research Institute, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia)

Other missions affected by space debris

The ISRO had to delay the launch of Singapore’s DS-SAR satellite onboard the PSLV-C56 mission on July 30 last year by one minute to avoid collision with space debris. According to the report, the ISRO had to carry out 23 collision avoidance manoeuvres (CAM) in 2023 to save its satellites from harm by space debris.

In August 2023, a large object found on the shores of western Australia was confirmed to be the debris of an ISRO rocket, likely from one of its Polar Satellite Launch Vehicle (PSLV) rockets.

In February, the dead Russian spy satellite Cosmos 2221 and NASA’s TIMED craft came uncomfortably close – 10 meters.

Earlier this month, China’s Shenzhou-17 crew repaired it space station’s core module’s solar wings, which had been damaged by space debris, through two spacewalks during the country’s first extravehicular maintenance mission, Xinhua reported.

Orbital debris damage seen during Hubble Space Telescope repairs. (Credit: NASA)

Time to stop relying on destruction of objects on re-entry into stratosphere?

In February, an Earth-observation satellite named Cartosat-2 that ISRO had launched in 2007 was lowered for a controlled atmospheric reentry over the Indian Ocean, and all major parts of the satellite were predicted to vaporize during the event.

This, however, may not always be the case as scientists realise that more objects survive the journey to the surface than previously thought. Just last month, for example, a piece of debris from a pallet of used batteries thrown overboard from the International Space Station — trash that NASA predicted would burn up completely — slammed into a home in Florida.

In the unpredictable path objects from space might take lies the risk of their “uncontrolled re-entry” into the stratosphere. In March this year, an alert was issued in Germany about an ISS battery pack following “natural” trajectory, Deutsche Welle reported. While it was predicted that the battery pack will fly over the country more than once before entering the atmosphere, it could have never predicted that the trajectory spanned from Latin America to northeastern Africa, the Middle East to South and Southeast Asia, and from Australia to most of Europe.

What initiatives are countries taking to go on cleaner space missions?

The NASA Orbital Debris Program officially began in 1979 in the Space Sciences Branch at the Johnson Space Center (JSC) in Houston, Texas. The program looks for ways to create less orbital debris, and designs equipment to track and remove the debris already in space.

Now, NASA has coined it sustainability strategy to encompass four domains – Earth, Earth orbit, cislunar space (the region near and around the moon) and deep space.

In April this year, Japanese company Astroscale’s satellite chased down a 15-year-old piece of space junk for the first ever rendezvous with such a big piece of space debris, and took an up-close image of it. The object is a discarded rocket segment that’s about 11m by 4m, with a mass of three tonnes. According to BBC, Active Debris Removal by Astroscale-Japan’s future missions will move in and grab hold of debris with the aid of robotic arms.

Meanwhile, efforts to address the issue of junk have now begun gathering serious investment. The latest early-stage idea is to mount artificial intelligence-powered lasers on satellites or other dedicated platforms and have them monitor space debris objects, space.com reported. When an object is suspected to be on a collision course with a valuable space asset, the lasers could, in theory, nudge that object into a safer orbit.

India plays its part

In late March, the Indian Space Research Organisation (ISRO) announced that one of its satellite missions “practically left zero debris in orbit” after a spent rocket stage was lowered to burn up in Earth’s atmosphere during re-entry.

Similar deorbiting techniques will be used to make future missions “debris-free” by the end of this decade, ISRO Chairman S Somanath said last week.

ISRO is an active participant in many international fora, such as the Inter-Agency Debris Coordination Committee (IADC) with 13 space agencies, the International Academy of Astronautics space debris working group, International Astronautical Federation space traffic management working group, International Organization for Standardization space debris working group and UN-COPUOS scientific and technical sub-committee for discussing space debris issues, related studies and the long-term sustainability of outer space activities.

What laws govern space clean-up?

There are no international space laws to clean up debris in space. But in October last year, the US Federal Communications Commission announced a settlement with Dish Network in the regulator’s first penalty related to space debris, CNBC reported. Dish admitted it was liable for failing to properly dispose of the EchoStar-7 broadcast communications satellite.

Most space-faring countries are signatories to the Convention on International Liability for Damage Caused by Space Objects, which deals mainly with damage caused by space objects to other space assets, but it also applies to damage caused by falling objects on earth. The Convention makes the launching country “absolutely liable” to pay compensation for any damage caused by its space object on the earth or to a flight in air.

This provision of the Convention has resulted in compensation payment only once so far — when Canada sought damages from the then Soviet Union, for a satellite with radioactive substance that fell into an uninhabited region in its northern territory in 1978.

Meanwhile, the World Economic Forum (WEF)’s Space Industry Debris Mitigation Recommendations mainly focus on how not to generate more space debris with the end-of-life operation of satellites and data sharing and traffic management in orbit for debris avoidance. They are guidelines, and are, therefore, non-binding.