Following up on preliminary studies assuming almost-Earthlike conditions, NASA commences work on a major robotic interplanetary landing mission called Voyager, which will use a Saturn IB rocket to send an orbiter with two landers to Mars. But NASA is doing so without much help from its usual interplanetary think-tank, Jet Propulsion Laboratory, whose scientists warn NASA that the latest astronomical data suggests a significantly thinner atmosphere and lower atmospheric pressure than the scenario for which NASA is designing its vehicles. As the complexity involved in creating self-guided landers with on-board laboratories increases, contractors begin to insist that only a Saturn V will do; since all Saturn V boosters are currently in reserve for Apollo lunar missions, NASA pushes the Voyager mission back into the 1970s.
