Today’s post is written by David Langbart, an Archivist in the Textual Records Division at the National Archives at College Park.
The reentry of space debris carries the potential to cause a major international incident. While most such remains burn up in the atmosphere, larger pieces can survive and cause damage, injury, or even death when they land. A major instance of this potential problem resulted from SKYLAB.
In May 1973, the United States launched into Earth orbit SKYLAB, a semi-permanent space station. A near-catastrophic launch disaster involving the micrometeoroid shield and the loss of one of its solar power arrays threatened the entire project. NASA technicians and astronauts effected repairs to the station and carried out three highly-successful long-term manned missions that accumulated significant scientific, technological, and medical data.
When the last manned mission left SKYLAB in February 1974, the orbiting laboratory was boosted into a slightly higher orbit and then largely faded from public view. Nonetheless, the laboratory was bound to fall to Earth and expected reentry was predicted as some time in early 1983. NASA eventually considered ways to extend SKYLAB’s life by moving it to a higher orbit or deboosting it in a very controlled manner. Initial planning was for a mission by the planned Space Shuttle to take care of that by deploying a remote controlled propulsion module that would attach to the lab. Delays in the shuttle program and increased solar activity that heated the atmosphere and dragged the workshop down faster than expected rendered that plan impossible. As a result, in December 1978, NASA announced it was discontinuing efforts to boost or de-orbit the lab. After that, NASA had only a modicum of control over the lab. They could “fly” it in an orientation that increased or decreased drag, thus giving some control over where it landed.
In the meantime, the demise of a Soviet satellite caused heightened international attention to the reentry of orbiting hulks and directed new attention to SKYLAB. In January 1978, Cosmos 954 reentered the atmosphere over northern Canada and scattered the remains of its power module, fueled with highly enriched uranium, over a wide area. In response to the international interest, the Department of State sent the following telegram containing NASA’s information about SKYLAB’s status. Given the controversy about the radioactive debris scattered by Cosmos 954, the Department added that SKYLAB carried no nuclear power sources.
Other junk was falling from space, too. In September 1978, in preparation for the reentry of another American spacecraft, called PEGASUS, the Department of State sent the following guidance on the general subject of dealing with questions involving space debris to American diplomatic and consular posts. The Department later referred to this guidance when dealing with questions about SKYLAB.
As it became clear that SKYLAB was coming down sooner rather than later, the Department and NASA developed a new and expanded briefing document for use by American diplomatic and consular officers in responding to questions and sent it out in hard-copy in November 1978.
Source: Department of State to All Diplomatic and Consular Posts, Airgram A-3831, November 9, 1978, P780167-0845, Central Foreign Policy Files, 1973-79/P-Reel Printouts, RG 59: General Records of the Department of State, U.S. National Archives.
The foreign concern was real. Not surprisingly, given their recent experience with Cosmos 954, Canadian officials expressed concern when briefed. The embassy in Ottawa sent this early report.
Among many others nations, the French and Germans expressed concerns as the date for reentry approached. The Department reported to the embassies in Paris and Bonn on meetings with their French and German counterparts.
Next: Part II-Coming Down.
 For more details on SKYLAB, see the official NASA history: W. David Compton and Charles D. Benson, LIVING AND WORKING IN SPACE: A HISTORY OF SKYLAB (Washington, DC: USGPO, 1983).
 The issue of sources of radiation came up again as the reentry approached. The Department provided guidance in Department of State to All Diplomatic and Consular Posts, Telegram 160833, June 22, 1979, 1979STATE160833, Central Foreign Policy Files, 1973-79/Electronic Telegrams, RG 59: General Records of the Department of State. After reentry, the question of radioactivity arose once more. Local Australian press quoted unnamed U.S. experts as saying the debris was radioactive. Ultimately, NASA authorized Department to say the debris was “no more radioactive than the luminous dial of a clock.” See the following telegrams: U.S. Embassy Canberra to Department of State, Telegram 06322, July 13, 1979, 1979CANBER06322, U.S. Embassy Canberra to Department of State, Telegram 06323, July 13, 1979, 1979CANBER06323, Department of State to U.S. Embassy Canberra, Telegram 180948, July 13, 1979, 1979STATE180948, and Department of State to U.S. Embassy Canberra, Telegram 181076, July 13, 1979, 1979STATE181076, all Central Foreign Policy Files, 1973-79/Electronic Telegrams, RG 59: General Records of the Department of State.
 Just a few weeks later, the Department notified posts that the efforts to boost or de-orbit SKYLAB described in the Q&A had ended. See: Department of State to All Diplomatic and Consular Posts, Telegram 318498, December 19, 1978, 1978STATE318498, Central Foreign Policy Files, 1973-79/Electronic Telegrams, RG 59: General Records of the Department of State.