In my opinion space exploration is worth the cost because if a meteorite hit the earth people would need to move onto an alternative planet for people to live on and it would need to be not to cold yet not to hot so everyone will not die. Also because, if we moved to a planet with living creatures on it, that could endanger our spicies. It can also be good because without knowing if there's living life in space the could invade earth. Another reason is when people mine on the asteroid belt it could help people financially, there could be fuel sources to stop pollution and could ne precious minerals for people.
The cost of space travel is not worth it. One of the reasons is because rockets could explode in orbit, palluting the earth and endangering people's lives. Plus, it's not worth it because of people set of to find aliens they might not find anything because it's very unlikely (in my opinion) to find anyone/anything. Another reason is if company's like space X and virgin use money to take people to space they might just get about 5 customers a year because the price is too much.