The tool pusher has a display of the weight of the drill string and
keeps the force on the drill bit at the optimum level. Also the first
few joints of pipe behind the drill are drill stem, really heavy wall
stiff pipe. Not sure of how they control the curve now, but do know
that the launch computer NASA used for the moon missions was the RCA
110A. A somewhat upgraded
version of the RCA 110 which was made to control oil well drilling. So
much for NASA's vaunted technical advances in computers.


Dan