The following is a photo and description from the White Sands Missile Range Museum.
This vehicle was used to test the parachute NASA planned to use to "soft land" the Viking on Mars. To simulate the thin Martian atmosphere the parachute needed to be used at an altitude more than 160,000 feet above the earth. A balloon launched from Roswell, N.M. was used to initially lift the aeroshell. The balloon drifted west to the missile range where the vehicle was dropped and the engines beneath the vehicle boosted it to the required altitude where the parachute was deployed. The tests were conducted in the summer of 1966.The IFO site also has a short video. I decided to check out YouTube and found several videos of the drop tests. If you go to YouTube and look for the other videos from this user, you'll find the others.
Finally, you might want to look at this build of a flying scale model of the PEPP Aeroshell on TRF - PEPP 1 Aeroshell Redux. I converted an Art Applewhite saucer to a PEPP-like model, but it is not even semi scale. And it only flies on one motor.