After 257 days in a locked steel capsule, an international crew of six researchers on a mock trip to Mars is preparing to simulate landing on the Red Planet.

The crew of three Russians, a Frenchman, an Italian-Colombian and a Chinese entered a cascade of modules at a Moscow research center last June to imitate the 520-day flight. Three of the crew are to don space suits to perform the mock landing Monday.

As part of the simulation they are to plant the national flags of Russia, China and the European Space Agency, take rock samples and test scientific equipment.

The mission doesn't involve weightlessness, but the organizers say it is useful because it recreates the confinement, fatigue and stress that future space travelers inevitably face.