(QHA) - Nasa's newest robotic explorer, Maven, rocketed toward Mars on a quest to unravel the ancient mystery of the red planet's radical climate change, Times of India reports. The Maven spacecraft is due at Mars next fall following a journey of more than 440 million miles (700 million kilometres). Scientists want to know why Mars went from being warm and wet during its first billion year to cold and dry today. The early Martian atmosphere was thick enough to hold water and possibly support microbial life. But much of that atmosphere may have been lost to space, eroded by the sun. "We want to know: What happened?" said Michael Meyer, Nasa's lead Mars scientist. To help solve this environmental puzzle, Maven will spend an entire Earth year measuring atmospheric gases once it reaches Mars on September 22, 2014. This is Nasa's 21st mission to Mars since the 1960s. But it's the first one devoted to studying the Martian upper atmosphere. As reported, the mission costs $671 million.