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Introduction

Last year, there were multiple instances of space debris potentially colliding with the International Space Station. Recently, another incident has brought attention back to this serious threat. Over the past few days, four spherical metal balls fell from the sky in villages in Gujarat.
According to experts, these balls are likely debris from a Chinese rocket or fuel storage tanks used in space launch vehicles. US-based astronomer Jonathan McDowell suggested on Twitter that these metal spheres are probably debris from the Chinese rocket Chang Zheng 3B, which may have fallen during its re-entry over Gujarat.
Retired ISRO scientist B S Bhatia stated that these metal balls could be fuel tanks that store hydrazine, a type of liquid fuel used in rockets and satellites. While scientists work to determine the exact nature of these objects, whether they belong to a satellite, a fuel tank, or something else, the larger concern is that incidents like these pose multiple threats to Earth, its inhabitants, functional satellites, and various space objects.
With the increasing number of space launches and events like space tourism, the space around Earth is becoming overcrowded, requiring urgent attention from countries to address the issue.

Space Debris

• Space debris presents a global threat to the continued use of space-based technologies that are crucial for communication, transport, weather and climate monitoring, and remote sensing.
• Predicting the probability of collisions with these space objects is vital for national security and for protecting Indian-owned public and private space assets.
• The actual amount of space debris is estimated to be between 500,000 and one million pieces, as current sensor technology cannot detect smaller objects.
• All of these objects travel at speeds of up to 17,500 mph (28,162 kmph), which is fast enough for even a relatively small piece of orbital debris to cause damage to a satellite or spacecraft.

Causes

• Space debris originates from dead spacecraft, spent rocket stages, lost equipment, boosters, and weapons, among other sources.
• The problem of space debris has become urgent, with objects in orbit becoming uncontrollable and posing risks to satellites and astronauts.

Impacts

• Space debris poses a global threat to the continued use of space-based technologies that are crucial for communication, transport, weather and climate monitoring, and remote sensing.
• Space junk is a danger to active satellites, unmanned spacecraft, and spaceships.

International Space Station:

• Although the ISS has Whipple shielding to protect itself from minor debris, certain parts, such as its solar panels, are not easily shielded.
• There is also the risk of the Kessler Syndrome or Kessler Effect, where one piece of debris collides with another, leading to a cascade effect that could contaminate an entire orbit with debris.

Earth
While most debris burns up in the atmosphere, larger objects can reach the ground intact. According to NASA, an average of one catalogued piece of debris has fallen back to Earth each day for the past 50 years.

Technologies

• NASA's Space Debris Sensor orbits the Earth on the International Space Station. REMOVEdebris, a satellite consisting of two cubesats, releases simulated space debris to demonstrate various retrieval methods.
• Under the e.Deorbit mission, two emerging technologies are being developed to capture wayward space junk.
• Other technologies include using a powerful laser beam to move objects. It is crucial to start implementing these technologies soon, as current scientific estimates predict that certain orbits will become unusable in the coming decades without active debris removal.

Way forward

• Improving cooperation between spacefaring nations would be beneficial.
• The 1967 Outer Space Treaty, negotiated during an earlier space race with minimal involvement from China, requires updating.
• Specifically, provisions that grant permanent property rights to objects in space may complicate debris cleanup efforts.
• Space agencies should invest in research on debris-removal technologies, such as those demonstrated by Astroscale, a Japanese startup, and consider partnerships with companies developing such technologies.
• The US should also aim to expand the Artemis Accords, a framework for space cooperation that currently involves 11 other countries.
• As more nations join, routine debris-mitigation protocols, including specifying responsible countries for end-of-mission planning, should be established.

Conclusion

Space debris is a concern due to its significant momentum despite its small size. The debris generated from the Mission Shakti Anti-satellite mission occurred at an altitude much lower than the orbit of the ISS. Therefore, Indian experts believe that the chances of it colliding with the ISS are relatively low. However, NASA is monitoring the situation for its own safety concerns.