Do American astronauts wear Sokol space suits when flying on a Soyuz?

Question

The Wikipedia article on the Sokol space suit seems to suggest that all personel traveling on a Soyuz vehicle must wear a Russian made spacesuit:

Each Soyuz crew member is provided with a made-to-measure suit for flight although, from the numbers made, it appears that the suits provided for ground training are re-used.

...

The suit is worn during launch and re-entry of the Soyuz spacecraft—the gloves are attached and the visor is sealed at these times.

                                                   

                                        ^{Peggy Whitson suited up in pressurized Sokol-KV2 suit.}

From this, it appears that American astronauts travelling on the vehicle would also wear the Soviet suit. Is this true? If so, why aren't the American suits adequate?

Answer 1

Yes. Sokol suits are suits that are highly specialized to the Soyuz spacecraft. An easy example of the specialization is the extra room in the hindquarters region to accommodate how far they have to bring their knees in when sitting in the couches. The American suits (by which I assume you mean the ACES suits), were not designed for this purpose -- they were designed to sit in a normal seat and to facilitate bailout (hence the parachute and the international orange color).