A radical change was introduced into the project in 1988, when it was proposed to use instead of the nuclear reactor an environmentally safe system based on film-type solar arrays on linear deployable trusses that passed developmental tests on-board space stations Salyut-7 and Mir. The main reason for this decision was the aspiration to make the vehicle environmentally safe. This decision was also greatly influenced by the progress in the development of film-type photovoltaic converters, which allowed to considerably simplify the construction of a high-power solar power plant.
The key parameters of the project are as follows:

• the total mission time is 2 years;
• the vehicle mass is 350 tons;
• the crew of four;
• the crew of two to land on the Martian surface;
• the crew to stay on the Martian surface for 7 days.

The plan was to carry out the expedition to Mars in incremental steps, starting with robotic probes and ending with the manned mission. The following three steps were envisaged:

• The first step was to develop the principles of joint operation of the elements of the Martian Vehicle using its models to be delivered on-board Progress logistics vehicles to a space station where they were to be assembled by the crew and to continue their mission in fre-flying atomated mode. These models were to equipped with scientific equipment needed to get a better knowledge of the Martian Vehicle operating environment.
• The second step was to be a dress rehearsal of the manned mission, where a solar-powered tug was to deliver to the Martian surface two landers instead of one, with one of the landers to be used for developmental test of the crew landing and return concept, while the other one, carrying several Mars rovers (the mass of about 20 tons), was to conduct a detailed survey of the Martian surface;
• The third step was the manned mission to Mars.