In his 1962 "we choose to go to the moon" speech, president john f. kennedy said: but if i were to say, my fellow citizens, that we shall send to the moon, 240,000 miles away from the control station in houston, a giant rocket more than 300 feet tall, the length of this football field, made of new metal alloys, some of which have not yet been invented, capable of standing heat and stresses several times more than have ever been experienced, fitted together with a precision better than the finest watch, carrying all the equipment needed for propulsion, guidance, control, communications, food and survival, on an untried mission, to an unknown celestial body, and then return it safely to earth, re-entering the atmosphere at speeds of over 25,000 miles per hour, causing heat about half that of the temperature of the sun-almost as hot as it is here today-and do all this, and do it right, and do it first before this decade is out-then we must be bold.

what is kennedy's claim in this excerpt?