The Official E-Newsletter of the Institution of Engineers Sri Lanka   |  Issue 48 - September / October 2020

Orbiting Debris of Planet Earth: A Space Environmental Problem

By Eng. S.V.A.S.H. Ariyathunge and Eng. H.M.K.K.M.B. Herath


Space debris, also known as space junks, is artificial materials which orbits the Earth but is no longer functional. The substance may be as big as the thrown-out rocket stage or as small as a microscopic paint chip. Most of the garbage is on a low Earth orbit in 2,000 km of the crust of Earth, but in a geostationary orbit, some fragments can be located at 35,786 km above the Equator. By 2020, more than 14,000 pieces of scrap waste were monitored by the United States Space Surveillance Network, which had a range larger than 4 inches. An additional 200,000 fragments measuring between 1 to 10cm (0.4 to 4 inches) in diameter to millions smaller than 1cm are expected to occur. It depends on the height of a piece of waste from space to fall back to the planet. Objects below 600 km travel many years before re-entering Earth's atmosphere. Artifacts hitting 1,000 km altitude for decades and we have still created some confusion as long as people are seeking space. Hundreds of dead satellites have orbited our planet through the years along with trash bits from all of our rockets.



With the first artificial satellite flight in 1957, space debris started piling up on the earth's orbit. Following the 1957 launch of Sputnik 1, North American Aerospace Defense Command (NORAD) has started to create a catalog of all identified launches and orbit objects: spacecraft, defensive shield, and launcher-style.


National Aeronautics and Space Administration (NASA) released updated copies of the database into a two-line feature package and re-published them at the beginning of the early 1980s. The trackers which supplied the database were notified of other orbital objects, many of which were due to in-orbit explosions. Many were purposely caused in the 1960s by the development of antifreeze weapons (ASAT), and some originated from orbital rocket stages, as the remaining propeller extended and its tanks exploded. NORAD team member John Gabbardkept has a dedicated website for enhancing monitoring. Gabbard developed a method to determine the orbital paths of its products in the analysis of the explosions and Gabbard diagrams are still commonly used. Such experiments have been used to enhance orbital evolution modeling and decline. When the NORAD database was made available in the 1970s, asteroid ceiling methods were added to the collection of known artificial Earth objects.

Orbital Debris Program Office (ODPO)

The NASA Orbital Debris Program Board (ODPO) has taken the lead globally in carrying out orbital analyses and establishing the scientific framework to take steps to minimize consumers within it. At Johnson Space Centre, the Department aims to enhance its understanding of the world of space debris and steps to monitor the production of waste. Near to earth, orbital debris tests are carried out with ground-based and space-based analyses of the condition of the orbital debris. Information is collected from ground-based radars and optical telescopes, space-based sensors, analysis of spacecraft surfaces returned from space, and ground-based laboratory experiments, such as DebriSat. The United States is a pioneer in collecting significant data points such as the Space Surveillance Network, the Haystack X-Band Radar, returned surfaces from the Solar Max, Long Duration Exposure Facility (LDEF), Hubble Space Telescope (HST), and the Space Shuttle. The results verify environmental models and recognize the existence of new sources.


Dealing with Debris

The most critical steps now are to avoid excessive orbital waste from being generated unnecessarily. This can be achieved by conservatively designing and operating cars. A variety of technological solutions have been taken since 2010 to reduce the development of space debris. Initially, most satellites were launched into elliptical orbits with perigees within an atmosphere to prevent the creation of toxic space waste. The orbit will quickly degrade and the satellites will then lose control. Although the International Telecommunication Union (ITU) allows geostationary satellites at the end of their lives to switch to a graveyard orbit, the orbital areas chosen do not effectively cover geostationary orbit (GEO) lanes. Satellites with a sufficient propellant can allow immediate, managed de-orbit or satellites, if they require too much propellant, can carry a satellite into an orbit that will ultimately de-orbit atmospheric drag. This was achieved for the French Spot 1 satellite, which reduced its reintroduction period from 200 to 15 years by raising its altitude from 830 km (516 mi) to approximately 550 km.

A well-informed solution uses a remotely-controlled vehicle to appoint, collect and return waste to the central station. The system includes Space Infrastructure Service, a commercially developed fueling depot and service spacecraft for geosynchronous orbit communications satellites originally scheduled to start in 2015. The Space Infrastructure Servicing (SIS) would be able to push dead satellites into graveyard orbits.

A ground-based laser is using to flatten the front of the waste and produce a rocket-like thrust, which slows down the load. The waste should collapse enough in continuous operation to be affected by atmospheric drag. The momentum of laser-beam photons can directly influence debris to push small waste away from the operating satellite in new orbits. In 2011, NASA work showed a laser beam fired on a piece of space trash that could give an impulse of 1 mm (0.039 inches) per second, while the laser could shift its path by 200m (660 ft) per day by holding it on the debris a few hours a day.

The potential for material decay is one disadvantage; the energy will breaking up the debris and contributes to the problem. The Japan Aerospace Exploration Agency (JAXA) is launched a "space net" research satellite on the 28th of February 2014. The launch was just a working test. In December 2016, Japan sent a collector of space debris via Kounotori 6 to the ISS, where JAXA scientists experimented with tethering debris from the orbit. A 700 m thin connected system from a spacecraft that was returning to Earth could not be expanded by the system. On the 6th of February 2014, leading researchers Koichi Inoue announced that they "believed the tether was not released" and the purpose of the project had failed. The European Space Agency has been planning a mission to eliminate wide field waste from space since 2012. The Deorbit project will launch in 2023 with the goal of extracting waste from Low Earth Orbit (LEO) over 4,000 kilograms (8,800 lb). There is an investigation into several capture techniques, including a net, harpoon, and a robot clamping arm. The Inter-Agency Space Debris Coordination Committee (IADC) for orbital debris has been developed by the world's leading space agencies to facilitate Earth orbit operations that restrict orbital debris production. In the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), the topic of evaluation and debate was also discussed since 1994. The international community has provided recommendations on the prevention of atmospheric debris to both the IADC and the COPUOS.

We will have planet waste streaming into the world and into the various outer regions of space. We pollute the cosmos even as we pollute the earth. The main way for getting rid of all the garbage that people create is by through recycling by reusing waste items by converting them into new goods. Most nations have introduced new ways of recycling and re-use and this would change the way we buy products, as we know that we need to reduce waste.


Eng. H.M.K.K.M.B. Herath
B.Tech Eng, AMIE(SL), AEng EC(SL), MIEEE
Department of Mechanical Engineering, Faculty of Engineering Technology
The Open University of Sri Lanka.