During the work on this piece, Torstensson suddenly realized that the material was far from exhausted, and that the dramatic subject matter called for an opera. It took him five years to complete this tremendous and complex work, which does not focus on the outward drama and the tangible suffering in the way that Jan Troell's film on the same subject does.
Instead weight is placed on portraying the psychological and sociological layers, for example based on the theory that André already knew before they set off that the undertaking was impossible, but that he carried on with it because he could see no way out without dashing the expectations of his contemporaries and sponsors.
Torstensson makes use of a large symphony orchestra with six percussionists and four soloists, as well as electronically processed sounds, for example, for breaking ice.
The score is particularly complex, with a wealth of nuances and details worked out in a modernist - but never post-modern - style.
Torstensson studied music in Sweden and electronic/computer-generated music at the Institute for Sonology in Utrecht in the Netherlands.
Torstensson has played at a large number of festivals, including the Nordic Music Days, ISCM World Music Days (Helsinki, Århus), Stockholm New Music (in March 1999 Torstensson was the main composer, along with Mauricio Kagel and György Kurtág, at that year's festival), the Holland Festival and Gaudeamus Festival (Amsterdam), Musique Nouvel Montréal, Wien Modern, Steirischer Herbst (Graz), Darmstadt, Time of Music (Viitasaari), Gaidafestivalen (Vilnius) og GASfestivalen (Gothenborg).
Torstensson has won the following prizes: "Matthijs Vermeulen-prisen" - the most important composer prize in the Netherlands (1991), and the Swedish counterpart: The Royal Swedish Academy of Music's "Stora Christ Johnson-pris" (1999).
Torstensson now lives and works in the Netherlands but has the world as his workplace.
The Expedition is recorded on CD by Donemus CV 100