Mars is currently a cold, dry, and barren planet with a thin atmosphere. However, in the next 1-3 billion years, it is expected to continue to lose its atmosphere due to solar wind erosion. This will result in further cooling and drying of the planet, making it even more inhospitable to life as we know it.
It is highly unlikely that Mars will ever become fully habitable for humans in the next 1-3 billion years. While there have been proposals to terraform the planet by introducing greenhouse gases to thicken the atmosphere and create a warmer climate, the process would take centuries and would require a massive amount of resources and technology that we currently do not possess.
There are several potential future missions to Mars that have been proposed, including manned missions to study the planet's geology and potential for life, as well as robotic missions to gather more data and samples. These missions could provide valuable insights into the history and evolution of Mars and help us better understand its potential for future exploration.
While it is possible for two planets to collide in the vastness of space, the chances of Mars and Earth colliding in the next 1-3 billion years are extremely slim. The orbits of the two planets are stable and do not intersect, and any potential collisions would likely be a result of external factors, such as gravitational disturbances from other celestial bodies.
If humans do eventually colonize Mars in the next 1-3 billion years, it could have a significant impact on the planet's future. Depending on the extent of human activity and development, it could potentially alter the planet's surface, atmosphere, and overall environment. However, the long-term effects of human colonization on Mars are still largely unknown and would depend on the responsible and sustainable practices of any future inhabitants.