Space Race | China’s rocket debris throws up disturbing questions

Source: AFP

The remnants of the Chinese Long March 5B rocket that splashed into the Indian Ocean north of the Maldives last week (May 9) did more than throw a scare in the world. It brought into focus the perils of ignoring the growing space junk orbiting Earth.

The Long March booster was used to launch the core module of China’s planned space station on April 29 and its last stage, weighing more than 20 tonnes, fell out of orbit plunging earthwards. A nervous planet waited for it to re-enter the atmosphere and burn up, hoping parts of the rocket that survived re-entry would splash into the ocean as nearly 75 percent of Earth’s surface is covered by water. The admission by the otherwise tight-lipped Chinese engineers that they had lost control of the plummeting rocket added to the jitters. Just last year, the fragments of another uncontrolled Long March fell on the Ivory Coast, but mercifully without any casualties.

Depleted rocket stages are usually jettisoned in lower orbits to enable ground controllers to nudge them into safer trajectories using strapped-on thrusters so that they burn up in the atmosphere. The China National Space Agency (CNSA) did not do this with the Long March nor did they consider the danger posed by the rocket as it spiralled in an elliptical orbit. Its arbitrary re-entry could have allowed debris to land on populated areas as far north as New York or as far south as New Zealand. That it landed on water had more to do with luck than the CNSA’s operational preparedness.

China has taken big strides in space exploration — from manned spaceflights and missions to the Moon and Mars — and has ambitious plans for an orbiting space station and a permanent lunar base from which to mine the Moon. But its space effort is underlined by recklessness that often pushes the envelope too far, as the wild re-entry of the Long March showed. Operational safety is non-negotiable in rocketry, and is a basic tenet of the space-faring community: China clearly violated this.

Beijing has dismissed concerns raised by agencies such as NASA as ‘double standards’, pointing to the crash of a Space X Falcon tank on Washington State in March. But the Long March’s core stage is eight times more massive than the Falcon’s second stage and re-entries of rocket parts happen after every launch. Only a small section of a launcher actually gets into orbit, the rest of it falling back to Earth. In the last 25 years, no spacecraft weighing more than 10 tonnes was deliberately abandoned to make an uncontrolled re-entry. That the CNSA got away with this breach is due to the absence of enforceable international space laws.

Even the crown jewel of all space law, the Outer Space Treaty (OST), drawn up in the 1960s, is silent on orbital debris as it never factored today’s exponential growth in space exploration. Its Article IX exhorts signatory states to conduct their space activities “so as to avoid… harmful contamination” of the Earth’s atmosphere. The ‘25-year rule’ (anything that a country puts into space should be de-orbited within 25 years of its mission end) voluntarily followed by space-faring nations is also obsolete in the face of sheer numbers as 3,500 satellites (and counting) currently orbit the planet.

Man-made junk comprising jettisoned rocket stages, abandoned satellites and blown-off hatches and insulation is the biggest hazard to the Near Earth Orbit (NEO). This region from around 900 km to 1000 km above Earth — home to navigation, communication and weather satellites — is where major collisions occur generating extensive debris. An exploding 2.5 tonne satellite in the NEO, for instance, creates millions of pieces of debris that could orbit Earth for millions of years. The fragile NEO is getting congested by the day with an estimated 22,000 pieces of space junk larger than a cricket ball, along with half a million pieces the size of a marble. But regardless of their size, it is their high velocities that can cause severe damage to spacecraft, posing a mounting threat to space exploration.

Similarly, spacecraft re-entries in the past have caused tension here on Earth. In July, 1979, parts of the US Skylab fell over a terrified Western Australia instead of the Pacific as its US controllers intended. In 1978, the Soviet satellite Cosmos 954 rained debris containing nuclear fuel over northwestern Canada (the Russians eventually paid the Canadians a hefty sum as compensation under the 1972 Liability Law). In February 1991, the 40-tonne space-base Salyut-7 broke up during re-entry: stunned Soviet ground controllers watched helplessly as its debris fell on a sparsely populated area near the Chilean border.

These issues cannot be adequately addressed as long as countries use loopholes in current space laws to suit themselves. With the Low Earth Orbit fast becoming the focus of commercial and military interests, it is of paramount importance to have stricter laws in place to ensure space-faring nations abide by global norms and best practices in their space activities.