A total of 189 moves ! That is one of the highest number of moves for a traditionnal 18-piece burr, only beaten by the Burrly Sane for Extreme Puzzlers of Jack Krijnen, with 209 moves, as I write these lines, in august 2011.
Tiros is named after TIROS-1 the first successful weather satellite launched in 1960 by NASA. TIROS stands for: Television Infrared Observation Satellite. Alfons chose this name because Tiros is indeed a very, very high object !
The original design has two colours. 6 pieces of each, plus 6 bi-coloured pieces, and has 96 assemblies and one solution. The version 2, with three colours and two kinds of distinctive edges, was designed by Guillaume Largounez in order to eliminate the 95 false assemblies, and thus propose an accessible assembling challenge to the puzzlist, which would otherwise be inhuman.
All traditionnal 18 piece burrs known to have more than 100 moves for the first piece, including the Burrly Sane ones, are based on the same original design, by Alfons Eyckmans, and have very similar disassembling sequences.