What does it take to build a helicopter to fly on Mars?
For starters, you can forget the remote control. Mars is more than 30 million miles away on a good day, so the time delay in sending and receiving signals means you couldn’t fly the spacecraft with a joystick — you have to send waypoints in advance from here on Earth and hope for the best.
It also needs to charge itself. And it has to be able to take off in the incredibly thin Martian atmosphere (roughly 100 times thinner than Earth’s atmosphere), meaning the entire helicopter — including solar panel, batteries, computers, rotors and landing gear — has to weigh less than 4 pounds. And how do you test it in a simulated
Whirling rotors pique the imagination, but remain a dream for the average man
CLONEL H. F. GREGORY, then chief of the Miscellaneous Projects Branch of the Army’s Materiel Command, was coming in for a landing at Wright Field. When he called the tower for permission to land, the operator said, “Sure, but where are you?” Whereupon, Gregory, who had been hovering directly over the tower roof in his Sikorsky R-4 helicopter, suddenly popped out of his hiding place to the astonishment of the tower operator.
Gregory’s little prank is typical of the now-you-see-it-now-youdon’t field of vertical flight. Ever since the day in May, 1940, when Igor Sikorsky, the great airplane designer and manufacturer, jammed on his upturned fedora and lifted his helicopter from the ground in its first public demonstration, the man in the street has been in a dither. Though Sikorsky