Smaragd was an experimental two stage hybrid rocket, launched by Copenhagen Suborbitals on July 27th 2012. It was designed to fly to an altitude in excess of 20 km and test long range radio communication and GPS response. Within the first two seconds of flight the nose cone however detached from the vehicle, and since all electronics were contained in the nose cone, almost no usable data was obtained. The vehicle however continued its flight and ignited the second stage as planned.


Smaragd project lead Flemming Rasmussen and booster lead Peter Madsen during final assembly on June 29th 2012.


Vehicle specifications
The Smaragd rocket was the first two-stage rocket built by CS. Both stages were propelled by hybrid rocket engines burning polyurethane oxidized by nitrous oxide. They both used the same valve-less hybrid rocket engine technology as seen on the Sapphire rocket.
The total length of the Smaragd rocket was 572 cm, the diameter of the first stage was 220 mm and the diameter of the second stage was 133 mm. Total lift off weight was 146 kg, of which 47 kg was propellant (33 kg for first stage and 14 kg for second stage).
The payload module was equipped with an onboard sequencer for timing of flight events such as parachute deployment. It was equipped with a video camera and a video transmitter, providing a live feed to mission control. Furthermore it carried a GPS unit and several sensors, namely a gyroscope, an accelerometer and a barometric pressure sensor.


Static test
Both stages were test fired in a static test on November 26th, 2011. The stages are designed such that the first stage provides a large but short acceleration, and the second stage provides a modest thrust such that the vehicle more or less maintains the speed acquired during the first stage burn. Thus the burn time of the two engines are 4 seconds for the first stage and 12 seconds for the second stage.

During the static test the first stage yielded a total impulse of 70,500 Ns and the second stage yielded a total impulse of 20,000 Ns



Static test of the Smaragd fist stage, November 26th 2011.



Pressure curves from the static test of the first stage. Blue is motor internal pressure, green is the oxidizer tank pressure and red is the pressure drop through the injector.



Pressure curves from the static test of the second stage. Blue is motor internal pressure, green is the oxidizer tank pressure and red is the pressure drop through the injector.


The Smaragd rocket was launched on July 27th 2012. At about 1.8 seconds after lift off, the nose cone separated from the vehicle due to a mechanical design fault. The vehicle however continued its flight, the first stage burned for the planned 4 seconds and the vehicle then coasted for 12 seconds before the second stage was ignited (ignition occurred via an electronic circuit that ams at liftoff ) Due to the loss of the nose cone, the parachutes were never deployed and both stages were lost to the ocean.


Ignition and lift off from the Sputnik launch platform east of Bornholm, July 27th 2012.


A few videos from the launch are available. A short video of the launch itself is found here:

Onboard video from the nose cone is found here:

A longer (20 min) video showing several details from the production and planning is found here: