enconpassing, as the preceding statenent notes, southern Africa, the Indian Oeean,the South Atlantic, and. some of Antarctica. 119/ Consequentlyo the initial_presumption of nany United States officials ffi scientists was that a nuclearexplosive d.evice with a yield of about two to fou" kilotons had been d.etonated bv South Africa in the Southern Henisphere. l2O/ 73. In l-ate 1979 an ad hoc panel of non-government scientists as convened byDr. Frank Press, Science Adriser to Presiden.b Carter, to assist in deternining thel-ikelihood that the light signal kras from a nucrear explosion. Based on thorouAhstudy, the report of this ad hoc panel (4/35/3!80 appendix ) conclud.ed: "1. The light si6inal from the September 22 event strongly resembles those previously observed from nuclear explosions, but it was diffelent fronthe others in a very significant way. The discrepancy suggests that the 113/ The Department of State Bu11etin, 25 October I9?9. U9l Eliot l{arsha}l, "tr'Lash ldot t{issed by VELA Still Veiled in Mist" o !g19g,vo1. 266, 30 November rgig, p. l-051; I'U.S. orrieiats Uncertain about that Eventnear South Africatr, llashington Post, 2? October 19?9. EE "U.S. Monitors Signs of Atouic Explosion near South -A.frica", Nev York Timesr^. ^ '---zo ucI'ooel Iyly.A/35 / \o2 English Annex Page 3J+ origin of ttre signal vas close to the satellite rather than near the surface of the earth. fn order to account for the September 22 VELA signal as coning from a nucl-ear explosion, one must hypothesize particularly anomal-ous functioning of the instrr.rment s (bhangmeters ) that observed- the event, "2. The bhangmeters on the VELA satel-lites have been triggered by and have recorded many previous nuclear explosions. They have also recorded hundxeds of thousands of other signals, mostly from lightning and cosmic raypartieles striking the light sensors. fn addition they have been triggered several hundTed tines by signals of unknorn origin, 'zoo events.r A fev of
**Analysis**
The text appears to be discussing a scientific event, specifically the detection of a light signal by a satellite, and the subsequent investigation into its origin. The text mentions scientists, panels, and reports, indicating a scientific inquiry. The topic is not related to economic development, agriculture, forestry, fishing, transport, communication, international trade, health, education, employment, humanitarian aid, or culture. The focus is on scientific inquiry and the analysis of a specific event.

**Category**
Science and technology