Glossary

Vela incident

In September 1979, a flash over the Indian Ocean detected by a US satellite was suspected of being a South African nuclear test, conducted in collabor-ation with Israel. No official confirmation of it being a nuclear test has been made. In 1997, South African Deputy Foreign Minister Aziz Pahad stated that his country had conducted a test but later retracted the statement. A number of other sources have quoted anonymous Israeli officials verifying that some sort of test took place, but nothing has been officially confirmed by the Israeli, South African or United States governments. In February 1994, Commodore Dieter Gerhardt, convicted Soviet spy and former commander of South Africa's Simonstown naval base, was reported to have said: "Although I was not directly involved …, I learned unofficially that the flash was produced by an Israeli-South African test code-named Operation Phenix. The explosion was clean and was not supposed to be detected … but the Americans were able to pick it up. “

Velocity

The distance per units of time or speed.

Verification

The process to collect data that demonstrates a party's compliance with an agreement or treaty. The Verification Regime of the CTBT includes an International Monitoring System, supported by an International Data Centre, consultation and clarification measures, and on-site inspections.

Verification technologies

For the CTBT, four types of technologies—seismic, hydroacoustic, infrasound and radionuclide—work in complementary fashion to monitor the underground, the water and the atmosphere for any sign of a nuclear explosion.

Verifying

Verification is the process to collect data that demonstrates a party's compliance with an agreement or treaty. The Verification Regime of the CTBT includes an International Monitoring System, supported by an International Data Centre, consultation and clarification measures, and on-site inspections.

Vertical proliferation

An increase in the size, quality, or destructive capacity of an existing weapon of mass destruction arsenal.

Visual observation

To attentively observe the natural environment in the inspection area with one’s own eyes is the starting point for visual observation. A skilled observer can detect anomalies in geological features or disturbances of vegetation that may point to a possible nuclear explosion in the underground. Visual observation can help the inspection team narrow down the inspection area or identify specific inspection activities that may be warranted.

VSAT

Very Small Aperture Terminal, a two-way satellite ground station with a dish antenna smaller than 3 meters.VSATs access satellites in geo-synchronous orbit to relay data from small remote earth stations (terminals) to other terminals. VSATs are the type of antenna most commonly used to transmit narrowband or broadband data in near real time from many IMS stations around the world to the CTBTO’s Inter-national Data Centre in Vienna, Austria.