It will probably take a more innovative technology for humans to reach Mars than simple chemical reaction rockets:
Costa Rica and U.S.-based Ad Astra Rocket Company announced over the summer that it had completed a record 88-hour high-power endurance test of its Vasimr VX-200SS plasma rocket at 80 kW. The test, conducted at the company's Texas laboratory near Houston, constituted a new high-power world endurance record in electric propulsion.