What makes human travel to the other planets in our solar system difficult?

Human travel to other planets in our solar system is challenging due to several factors, including vast distances that require extended time in space, which poses risks to human health from radiation exposure and psychological stress. Additionally, the need for life support systems to provide air, water, and food complicates mission planning and logistics. Moreover, the harsh environments of other planets, such as extreme temperatures and atmospheric conditions, demand advanced technology and robust spacecraft capable of withstanding these challenges. Finally, the significant financial and resource investments required for such missions further complicate human exploration beyond Earth.