It's Mars landing day!

NASA's Phoenix lander is on course to land on the red planet at around 4:53 p.m. Pacific Daylight Time (7:53 Eastern Daylight Time).

There are two more chances to carry out small correction maneuvers -- 6x and 6xm -- as Phoenix speeds toward Mars for its entry, descent, and landing and landing at a pre-determined site.

Gary Napier, spokesman for Lockheed Martin Space Systems -- the firm that designed and built the Phoenix lander -- told me: "The only reason we would use them is if the gravity well of Mars does something outside of our prediction. Right now, the prediction is we're on target and we're going in."

That "going in" includes seven-minutes of nail-biting as Phoenix hot foots it through the Martian atmosphere, deploys its parachute, tosses off its heat shield, lowers its landing legs, turns on its landing radar, discards its parachute...then fires its gang of 12 thrusters to slow down for a touchdown. 

And here's even more history for you.

On this day, back on May 25, 1961, President John F. Kennedy presented a bold challenge before a joint session of Congress - to send a man to the Moon, and accomplish that feat by the end of that decade.

While you're waiting for the Phoenix Mars landing today, retrofire yourself back in time and listen to President Kennedy's speech that put the nation on course for, not only lunar exploration, but beyond.

Go to:

http://www.archive.org/details/jfks19610525

Under "individual streams" go to the first item labeled "stream".

-- Leonard David