This first prototype of the 10,000 Year Clock is currently on loan to the Science Museum of London, and can be seen as the final piece in the “Making of the Modern World” exhibit. This prototype began to tick on December 31, 01999 after an almost three year research and design effort. Following lead designer Danny Hillis, the team included project manager and designer Alexander Rose, mechanical engineer Liz Woods, horologist David Munro, and lead machinists Chris Rand and Erio Brown.

Power for the Clock comes from the two helical weight drives on either side of the Clock. The timing for the Clock is generated both by a torsional pendulum, with a one minute period, and by a Solar Synchronizer that re-calibrates the Clock to solar noon on any sunny day. To correct from solar time to the absolute time of the pendulum there is a special Equation of Time Cam. The display on the Clock is made of two elements; the Serial Bit Adders and the dials. The Adders convert the timing generated from the pendulum, using their binary mechanical system, to changes in the Clock's dials. The six dials represent the year, century, horizons, sun position, lunar phase, and the stars of the night sky.

The Clock was primarily designed by Danny Hillis, additional design work and project management by Alexander Rose. Engineering and part drawings were done by Elizabeth Woods. The Escapement and movement were designed and built by David Munro and General Precision Corp. Almost all other Clock parts were machined and assembled at Rand Machine Works.

All engineering for the Clock of the Long Now is done in Pro Engnineer courtesy of PTC. All CAM processing is done in GibbsCAM courtesy of Gibbs & Associates. The Long Now Foundation thanks them for their support.