OPINION | SpaceX and the looming space-debris crisis

Elon Musk’s aerospace company SpaceX has just completed the largest initial public offering in history, raising approximately $75 billion by offering just 5 per cent of the company’s shares. This puts the valuation of SpaceX at around $1.8 trillion, making Musk the world’s first trillionaire who is in control of a company whose financial heft matches the nominal GDP of South Korea—the world’s 13th largest economy.

With the SpaceX IPO, the world has officially entered a new era of the space race. Along with SpaceX, Boeing’s Starliner, Richard Branson’s Virgin Galactic, Jeff Bezos’s Blue Origin, the US government’s NASA, Russia’s ROSCOSMOS, the China National Space Administration, the Indian Space Research Organisation and the European Space Agency are contributing to the development and utilisation of space technology. With billions of dollars being invested in space exploration by these companies and agencies, we are soon going to witness unprecedented growth in launches, satellites, space stations and other space-based activities.

But amid the excitement surrounding this new space age, a serious, hidden problem is growing rapidly in Earth’s orbit—the growing risk of space debris. Today, satellites are increasingly being forced to perform avoidance manoeuvres to dodge orbiting debris. As we strive to achieve greater progress in space, we are simultaneously making the space-debris problem worse.

The enormous accumulation of waste in outer space has a history of decades. On October 4, 1957, the launch of the first artificial satellite, Sputnik 1, took place. The satellite, which orbited the Earth at 215km x 939km at a speed of around 28,000 kilometres per hour, had its batteries operational for only 22 days. Subsequently, Sputnik continued to orbit the Earth as inert space debris.

On January 4, 1958, the satellite’s orbit decayed and it entered the Earth’s atmosphere, burning up.

On November 3, 1957, Sputnik 2 was launched. Including the dog Laika, Sputnik 2 weighed 508kg. By November 10, its batteries were no longer operational. The upper stage of the launch vehicle and Sputnik continued to orbit for a long time in an inert state.

According to the principles established under the Outer Space Treaty of 1967, outer space is open to exploration and use by all nations. The Kármán Line at 100 kilometres above sea level is widely recognised as the boundary of outer space. Space research and activities conducted above this altitude are generally regarded as taking place in outer space.

Any object in outer space that is no longer useful can be called space debris or space junk. In the past 68 years, around 14,900 satellites have been launched from Earth. Only about 8,000 of them are currently operational. The nonfunctional ones, along with their associated thrusters, solar panels and the upper stages of launch vehicles, drift rapidly in orbit in a deteriorated condition. Satellites and rocket components can also break down into small, indestructible fragments that continue orbiting Earth for decades.

A large portion of the debris generated by humans orbits close to the Earth. This includes particles of paint on spacecrafts and non-functional artificial satellites, as well as rocket remnants. According to the European Space Agency, around 34,000 objects larger than 10 centimetre orbit the Earth. Approximately 9,00,000 objects measuring between 1 centimetre and 10 centimetre, and 128 million objects measuring between 1 millimetre and 1 centimetre have been accumulated as space debris. According to ESA, humans have introduced 4,300 tonnes of debris into Earth’s orbit. These objects travel completely uncontrolled at speeds of around 28,000 kilometre per hour.

The upper stage of America's Centaur rocket, used for lunar exploration, is an example of space debris that has been orbiting in space for a long time. On September 20, 1966, the Surveyor 2 lunar exploration spacecraft was launched from Earth on an Atlas-Centaur rocket. Although Surveyor 2 came within 130 kilometres of the moon, it failed to land at its intended target, the Copernicus field, and crashed onto the lunar surface on September 22. The Centaur upper-stage rocket subsequently entered an orbit around the Sun, and for decades, there was no information about its whereabouts.

For some time, the bright object known as SO 2020, found in the Sun’s orbit close to Earth and observed by NASA’s Pan-STARRS1 survey telescope, was misunderstood to be an asteroid. Later, NASA discovered that this object was not an asteroid but rather good-quality steel—and therefore man-made. In December 2020, NASA confirmed that the object was the upper-stage motor of the Centaur rocket that had launched Surveyor 2. It was after 54 years that this abandoned piece of space hardware returned to Earth’s vicinity.

According to information provided by the US Space Surveillance Network—a global system of sensors, radars and optical telescopes operated by the US Space Force and the US Space Command—most debris is found in Low Earth Orbits, ranging from 300 kilometres to 2,000 kilometres in altitude. Of all the objects orbiting the Earth, 59 per cent are fragments resulting from collisions and explosions of man-made objects. As much as 16 per cent are inactive satellites and 12 per cent are rocket remnants. Only 6 per cent of the total objects are currently actively functioning artificial satellites. The remaining 94 per cent are man-made objects and debris without any use. Today, the situation is heading towards a state where such debris hampers space missions. The growing problem of orbital debris poses risks to active satellites, space missions and even future exploration.

Space debris poses major threats to the operation of active spacecraft and, potentially, life on Earth. Collisions between debris and operational satellites or spacecraft can cause serious damage.

In 1978, NASA scientist Donald J. Kessler proposed a scenario that later came to be referred to as the Kessler Syndrome. It describes a runaway chain reaction in Low Earth Orbits. Kessler syndrome occurs when the volume of space junk in a particular Low Earth Orbit becomes so high that collisions between objects generate even more debris in a cascading chain reaction. If left unchecked, this could render certain orbital pathways completely unusable and render all space exploration activities ineffective.

If pieces of space debris undergo orbital decay and reenter the Earth’s atmosphere without completely disintegrating, they can fall into inhabited areas. The presence of debris makes it difficult to observe space and can interfere with communication. If the accumulation of debris continues unchecked, parts of Low Earth Orbits could become unusable for years.

President Draupadi Murmu has reiterated India’s commitment to making all of its space missions debris-free by 2030. This formed part of an important announcement made on National Space Day last year.

After using the upper-stage motor of PSLV-C60, launched on December 30, 2024, for space-docking experiments and various scientific activities under the POEM-4 programme, ISRO de-orbited the stage to a lower orbit. It subsequently reentered the Earth’s atmosphere and fell into the Indian Ocean. This event highlights India’s commitment to keeping space free of debris.

Keeping space clean is not just a technical challenge; it is a responsibility that humanity owes to the future. With the SpaceX IPO, the space race can only accelerate—dramatically increasing the number of objects in orbit that are potential debris. This is all the more reason for nations to cooperate and take prompt action to reduce orbital debris and ensure that the path forward for space exploration remains clear.

The author is a former ISRO scientist. 

The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.