NASA have released a report laying out some research results around an “impossible” microwave thrusters, which might confirm. a major breakthrough in space propulsion. Wired also has a follow up, 10 questions about Nasa’s ‘impossible’ space drive answered.
This compares with Nasa’s plans using conventional technology which takes six months just to get there, and requires several hundred tons to be put into Earth’s orbit to start with. You also have to stay there for at least 18 months while you wait for the planets to align again for the journey back. The new drive provides enough thrust to overcome the gravitational attraction of the Sun at these distances, which makes manoeuvring much easier.
A less conservative projection has an advanced drive developing ten times as much thrust for the same power — this cuts the transit time to Mars to 28 days, and can generally fly around the solar system at will, a true Nasa dream machine.