 I think they realized even at that time that it would not be, it would be very difficult to have a permanent Mars base. So mostly they're focusing at that time on short-term expeditions to Mars, when Moon is always considered as a permanent base on the Moon is very important and centerpiece of the program. But for Mars, they're only talking about at that time, short-term expeditions, one-time flights with very short stay on the surface of Mars.