Why Care About Space Sustainability?

In a world inundated with many complex and urgent problems, why should space sustainability matter? Because if outer space is not safe, secure or peaceful, the ability to use it could be denied to all, thus we would be unable to use space for national security purposes, Earth observation,  telecommunications (including financial trans­actions, internet, telephone, data transfer and tele­vision), navigation, scientific exploration, and economic development. In fact, human spaceflight in Earth orbit could also come to an end as well. Addressing the inputs to space sustainability now means we can prevent trends from becoming norms, and ensure that outer space is useable for all.

Collision-PhilSmithAccidents in outer space must be avoided in order to prevent loss of life and creation of damaging orbital debris.

February 10, 2009

  • On February 10, 2009, two satellites collided accidentally, creating a large amount of debris circling the Earth 800 kilometers above our heads.
  • Hundreds of bits of metal, foil and plastic spreading along and around the former satellites' orbits now threaten other satellites.
  • Although one satellite was already out of service, the other helped provide worldwide telephone services. While there was data beforehand showing that this collision was possible, it was impossible to know for sure whether it would happen.
  • Unfortunately, there are not enough resources to track every ob­ject in space, and we don't have a system in place to inform all space opera­tors about what's going on and potential danger. In such an environment, another collision isn't just likely, it's a certainty.

January 11, 2007

  • On January 11, 2007, as China's inoperable Fengyun-1C weather satellite passed overhead, a modified Chinese ballistic missile was launched from China's Xichang Satellite Launch Center and streaked toward the satellite, deliberately colliding with tremendous force and creating thousands of small pieces.
  • This cloud of debris quickly spread out across a large region of Earth orbit, covering between 300 and 2,000 km in altitude.
  • Many of these pieces remained in the original po­lar orbit, the prime location for most Earth observation satellites, including weather and climate satellites oper­ated by NASA, NOAA, and ESA.
  • The deliberate satellite destruction created some 2,500 trackable pieces of orbital debris (larger than about 10 cm or 4 in). NASA's debris experts estimate that the test created perhaps as much as 300,000 pieces of debris too small to track.

Debris-generating kinet­ic-kill ASAT weapons like this Chinese example have become a major international concern, primarily because of the large amounts of debris they create. During the 1970s and 1980s, the former Soviet Union and the United States tested their own forms of these ASATs, but decided that they were of limited tactical or strategic use, in part because of the collateral damage to their own satellites from the large amounts of orbital debris.

 

U.S. Destruction of USA 193--Aegis SM-3 MissileAegis

  • In February 2008, the United States made a decision to destroy USA 193, an ailing national security satellite that carried substantial amounts of highly toxic hydrazine fuel and was destined to re-enter the Earth's atmosphere within a few months.
  • Officials opted to shoot it down using a modified Aegis SM-3 missile, launched by the USS Lake Erie (pictured) to ensure that the hydrazine would disperse harmlessly on re-entry, a threat many experts felt was un­realistic.
  • Unlike China, the United States specifically designed the intercept to generate as little debris as possible and gave international briefings on the operation, in accordance with international agreements.
  • Within eight months, the few hundreds of pieces of resultant debris reentered the at­mosphere.
  • Despite assurances by U.S. officials that the intercept was spe­cifically designed to reduce the risk to public safety, many people never­theless saw this event as a dangerous example of how a U.S. anti-ballistic missile defense system can be modified into an ASAT weapon, a concern that increases with planned upgrades in the Aegis interceptor that will make it even more powerful and thus able to reach higher orbits in the future.

Analysis

  • While neither the Chinese nor the U.S. intercepts were carried out as acts of war, the two actions highlight that intentionally destroying a satellite or otherwise purposefully creating orbital debris endangers all space actors, including the perpetrator.
  • In short, use of kinetic-kill ASATs renders the realm of outer space more hazardous for future use. These events highlight the need for mechanisms designed to eliminate the deployment and use of such weapons. Some propose a code of conduct for outer space, others a treaty banning all ASATs.