Archeops experiment aimed at measuring the cosmic
background emitted just after the Big Bang. The study of this radiation
is essential to obtain precise information on the evolution of the
Universe: density, Hubble constant, age of the Universe... To achieve
this goal, measurements have been done with devices cooled down at
temperature placed at the focus of a warm telescope. To avoid
atmospheric disturbance the whole apparatus is placed on a gondola
below a helium balloon that reaches 40 km altitude.