Improvement of the extravehicular activity suit for the MIR orbiting station program

Since 1977, EVA suits of the semi-rigid type have been used to support sorties from Russian orbiting stations. Currently, within the MIR station program, the Orlan-DMA, the latest modification of the Orlan semi-rigid EVA suit is used by crewmembers. Quite some experience has been gained by Russia in operations of the Orlan type suits. It has proved the advantages of the EVA suit of a semi-rigid configuration, featuring donning/doffing through a hinged backpack door with a built-in life support system. Meanwhile there were some wishes and comments from the crewmembers addressed to the enclosure design and some LSS components. Currently a number of ways and methods are being developed to improve operational characteristics of the suit as well as to enhance its reliability and lifetime. The forthcoming EVAs to be performed by the STS-MIR crewmembers and future EVAs from the common airlock of the International Space Station Alpha make implementation of the planned improvements even more consistent. The paper analyzes the experience gained in the Orlan-DMA operation and discusses planned improvements in light of the forthcoming activities. In particular the Orlan enhancement program is aimed to make the donning/doffing easier, enhance enclosure mobility, improve the condensate removal unit, increase the CCC (Contamination Control Cartridge) operation time and simplify the onboard subsystem design concept.