MARS is a British high power - amateur rocketry group. This project uses a kosdon O-10,000 (can you tell I am a bit obsessed with this motor?) and a boosted dart rocket. The goal first of all was to set a new UK altitude record (which they did) and try to attain altitudes above 50,000 feet.
For those new to this topic, boosted darts are rockets that, due to a lack of any motor in them, can be made as aerodynamic and dense as possible. When combined with a large quick burning booster (which they drop off right away before drag from the booster slows them down) they can attain much higher altitudes than with a rocket that has to carry the O-10,000 with it for the whole flight. For the longest time, a boosted dart launched with an R motor (by RRS) held the altitude record in amateur rocketry.
The flight worked pretty well, however it only attained around 35,000 feet for unknown reasons (they suggest a separation failure). Still an O-10,000 flight that recovers is a success on it's own. They did get the new UK record, despite the reduced performance. The previous record was only 15,000 feet or so.