Why does the trash matter? For more than 50 years, humans have been investigating the surface of Mars. Nations have dispatched 18 human-made items to Mars in 14 separate missions, according to the United Nations Office for Outer Space Affairs. Many of these missions are still underway, but humankind has left a large amount of trash on the planet's surface after decades of … [Read more...] about Mars is Littered with 15,694 Pounds of Human Waste From 50 Years Of Robotic Exploration