In the first versions of the engine the propellants are driven to the engine by using a
pressure-fed cycle with
helium. Later versions of the engine (TEPREL-C) incorporate a
turbopump.
TEPREL-A With the TEPREL-A engine, first tested in 2017, the company included several design upgrades, such as a new
combustion chamber design, an improved
injector geometry and a
regenerative cooling system. The later enables the engine to fire for nearly 2 minutes, which is the envisaged nominal functioning duration for the suborbital launch vehicle
Miura 1. At sea level, the engine produces a thrust of 32 kN. and a
convergent-divergent nozzle, all regeneratively cooled. In May 2019 the first unit of this model was destroyed during a test. After a long investigation PLD Space concluded that the problem was due to excess pressure during engine start at ignition. PLD Space addressed the issue through a combination of improvements to the launch site infrastructure and procedural improvements. It is currently fully operational. In February 2020, PLD Space successfully completed a 122-second test that allowed it to achieve flight rating. On August 28, 2020,
PLD Space completed required tests for the thrust vector control system on the Teprel-B rocket engine. to be used in the
Miura 5 rocket. Initially it was expected to produce 105.5 kN of thrust at sea level. Later expected thrust was increased to 190 kN.
TEPREL-C Vacuum Version of TEPREL-C adapted to vacuum, and capable of re-ignition in microgravity conditions. Capable of 75 kN of thrust. ==References==