Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>According to this article:"When the Apollo modules reached Earth’s atmosphere after a three-day trip from the moon, they were moving at about 30,000 fps. Orion’s velocity will match this on its own lunar return. But returning from Mars, it will be moving close to 35,000 fps. That speed, about 6.6 miles per second, would take you from Washington, D.C., to New York City in less than 30 seconds."I think it would take an enormous amount of propellant to slow a craft returning from Mars enough to go into Earth orbit (of any height). <br /> Posted by centsworth_II</DIV><br /><br /><BR/><BR/>"Skip-return" trajectories are being considered to allow some flexibility in landing zone, and a return to Earth orbit could be achieved with minimal fuel by using an aerocapture maneuver. However human flight to Mars with this technology would be impractical.