The Mk IV hybrid motor uses hydroxl-terminated polybutadiene (HTPB) as a fuel and nitrous oxide (N2O) as an oxidizer. The motor generates 2,500 pounds of thrust at sea level and up to 2,800 pounds of thrust in vacuum.  The engine went through a rigorous testing campaign, completing two cold flow and two hot fire tests.

As BURPG’s fourth installment of the Mk series, the Mk IV motor was set to fly on the Quasar Launch Vehicle which featured:

  1. An electronic pressure regulator
  2. Wagon wheel stacked solid fuel grain design.
  3. A welded light weight tank structure.
  4. RCS (Roll/Reaction Control System).
  5. A single-piece injector plate.
  6. A lean nozzle and chilled nitrous.

Quasar was scheduled to be launched during the summer of 2014, from Black Rock Desert, Nevada. The flight was called off in order to push funding towards the Mk V and the Starscraper Launch Vehicle. 

Mk IV Technical Overview

Height: 21 ft (6.4 m)
Launch Mass:  320 lb (145.15 kg)
Diameter: 8.3 in (2.53 m)
Burn Time: 12 sec
Thrust at Sea Level: 2,500 lbf (11.121 kN)
Thrust in Vacuum: 2,800 lbf (12.455 kN)
Stages: 1