ARPANSA - Australian Radiation Protection and Nuclear Safety Agency

What happens when space debris re-enters the earth's atmosphere?

Over recent years thousands of individual items of hardware have been placed in space orbit, varying in size from a few cubic centimetres to complete space laboratories weighing many tonnes with some having on-board nuclear reactors. Whilst most items disintegrate and burn up entirely on re-entry into the earth's atmosphere, experience has shown that it is possible for pieces of considerable size and weight to reach the surface of the earth.

Has this happened before?

In 1978 the USSR's COSMOS 1 and COSMOS 954 re-entered the earth's atmosphere and scattered radioactive debris over an area of 100,000 sq km of north-western Canada. In 1988 the US SKYLAB did not burn up completely on re-entry and scattered non-radioactive debris on Western Australia.

Russia launched the Mars 96 probe from Kazakhstan on 16 November, 1996. The launch failed and left portions of the probe in a low earth orbit. The remaining portions of the probe eventually plummeted to earth and landed in the Pacific ocean between Easter Island and Chile on 18 November, 1996.

Fortunately no one suffered injury or property damage from these incidents, but they highlight that there is danger to life and property from space debris, which could include radioactive fallout.

Who is keeping an eye on the situation?

The orbital decay and subsequent re-entry of debris is closely monitored by the North American Aerospace Defense Command's (NORAD) Satellite Tracking Organization and other similar tracking facilities around the world. The lack however of precise information in some instances, particularly on timing and location of possible re-entry of an uncontrolled object over Australia, will mean detailed planning of response operations will be precluded until after re-entry and impact occurs.

Some space vehicles have on-board safety mechanisms designed to separate some of the component parts before re-entry. If this occurs, the behaviour of these component parts will also differ from the forecast behaviour of the whole vehicle and multiple re-entry events could occur and be separated by days or even weeks. This could result in multiple activation of plans for a single space vehicle.

Role of ARPANSA in the event of re-entry of space debris

The Australian Contingency Plan for Space Re-Entry Debris (AUSCONPLAN-SPRED) has been prepared to coordinate the activities of Commonwealth, State and Territory Departments/Authorities involved in recovering and neutralizing any radiological threat arising from the re-entry of space debris over Australia and the island territories. Emergency Management Australia (EMA) coordinates emergency responses under this plan.

Under AUSCONPLAN-SPRED, the ARPANSA provides:

• A Principal Scientific Adviser to Emergency Management Australia in the National Emergency Management Coordination Centre.
• A Senior Scientific Adviser to the Australian Space Debris Emergency Search Team (ASDEST), to be responsible for:
  • technical control of the radiological operations of the ASDEST, including adequate detailed documentation; and
  • provision and overall coordination of non Defence Force radiological elements assigned to ASDEST.
• Health radiation advice and relevant physicists, technicians and equipment to meet, in conjunction with the Australian Nuclear Science and Technology Organisation (ANSTO). the requirements of the plan.
• Analytical support, as necessary, within and external to the ASDEST for identification of radiation hazards to personnel and the environment.
• Advice and assistance in training of ASDEST Ground Radiological Teams on health aspects.
• In concert with the ANSTO, advice on:
  • likely radiological effects and measures to be taken in the event of a radioactive space debris incident.
  • radiological detection equipment (other than airborne equipment) and other resources required and available for the detection and neutralization of radioactive material and contamination resulting from space debris.
  • details to support the plan relating to personal and environmental hazards, public safety advice, assessment of maximum acceptable radiation levels that can be retained and identification of specialized equipment and technical and scientific personnel required.
  • preparatory or preventative action that may be taken by members of the public.

Reference

"Australian Contingency Plan for Space Re-Entry Debris (AUSCONPLAN-SPRED)"
Emergency Management Australia, PO Box 1020, Dickson ACT 2602 (2003).
N.B. As at January 1997 this document is being revised to broaden its applicability.

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