1. With carbon dioxide accounting for about 95% of the atmospheres of both Mars and Venus, why is there little greenhouse effect on Mars today? 2. If you were designing a space vehicle to land on...

1. With carbon dioxide accounting for about 95% of the atmospheres of both Mars and Venus, why is there little greenhouse effect on Mars today?

2. If you were designing a space vehicle to land on Venus, what special features would be necessary? In what ways would this mission and landing craft differ from a spacecraft designed for a similar mission to Mercury?