Forty-one years ago this month, the first long-tank thrust-augmented Delta rocket with six Castor-2 strap-on boosters was launched from LC-17A at Cape Canaveral, Florida. Known as Delta M-6, the thrust-augmented launch vehicle was capable of placing 1,000 lbs in geosynchronous transfer orbit (GTO) or about 2,850 lbs in low earth orbit (LEO). Three of the solid strap-on boosters were ignited on the pad along with the MB-3-3 first stage liquid rocket motor which generated 195,000 lbs of vacuum thrust. Each solid rocket strap-on produced 58,000 lbs of vacuum thrust and burned for 37 seconds. At T+38 seconds, the remaining three strap-ons were air-ignited just as the ground-ignited motors were burning out. All of the Castor-2 solid rockets separated from the launch vehicle shortly after burnout of the trio of air-ignited motors. The ground-ignited boosters went first, followed 5 seconds later by the air-ignited set. The primary payload for the Delta M-6 mission was the Explorer 43 satellite which was inserted into a highly-elliptical orbit on Saturday, 13 March 1971. Orbital parameters included an apogee of 122,146 statute miles a perigee of 146 statute miles and an orbit inclination of 28.75 degees. Outfitted with a dozen specialized instruments, Explorer 43 obtained detailed scientific measurements of solar ray, cosmic ray, electrical field and energetic particle activity in space. These data allowed scientists to study the cislunar environmnt during a period of decreasing solar flare activity. Explorer 43 performed well right up to the day it reentered the Earth’s atmosphere on Thursday, 02 October 1974.