About this episode
On July 20, 1976, Viking 1 became the first robotic lander to land on Mars. On September 3, its sister Viking 2 followed suit. Both of them carried experiments to test for biology on Mars, something which no subsequent Mars lander since has replicated. The results from these chemical experiments have divided researchers for decades and have been the cause of one of the greatest debates in planetary science. Learn more about your ad choices. Visit megaphone.fm/adchoices