Copenhagen Suborbitals was founded in 2008, but it was the launch of HEAT-1X that put CS in media all over the World for the launch attempt in 2010 and again for the actual launch in 2011. The public interest grew dramatically and an independent group founded Copenhagen Suborbitals Support, which today forms the economic foundation of CS. In that sense, the launch of HEAT-1X has turned out to be one of the most important moments for CS.




HEAT-1X development
HEAT-1X was the first rocket to be launched by CS. With a lift off mass of 1630 kg and standing 9.38 m tall it was, and to this date still is, one of the largest amateur rockets ever built. It was developed as an experimental test vehicle intended to answer several key questions such as:

  • Is it possible to fly an un-guided, passively stable rocket of this size?
  • Is it possible to launch a vehicle of this size from a custom built sea launch platform?
  • Is it possible to build a spacecraft capable of supporting an astronaut with a maximum outer diameter of 65 cm?

Naturally it also involved development of a rocket engine powerful enough to propel the vehicle. A hybrid rocket engine design was chosen and during initial testing paraffin was used as solid cast fuel in combination with liquid oxygen as the oxidizer. This had been successfully tested on smaller engines but in full scale with a fuel grain of about 375 kg, stability of the paraffin grain proved to be an issue as several large chunks of paraffin was ejected from the engine during operation. This caused a shift to a polyurethane propellant.



Static test of HEAT-1X paraffin/LOX engine, February 28 2010.


The polyurethane propellant version was successfully tested on May 16 2010 and proved to be much more reliable, although the engine did exhibit a strong 8 Hz oscillation. Data showed an initial thrust of 65,000 N and a total impulse of 527,000 Ns over 15 seconds.



Static test of HEAT-1X PUR/LOX engine, May 16 2010.


2010 launch attempt
The first attempt to launch HEAT-1X was on September 5th 2010. The rocket was carrying the Tycho Brahe spacecraft and a full size and 80 kg heavy crash test dummy, Rescue Randy. The small fleet of vessels participating in the launch left Spaceport Nexø at 1 AM in less than optimal sea conditions for a 7 hour trip to the launch site. Sputnik, the launch platform, was towed by Flora and pushed by UC3 Nautilus. Several key members of the launch crew were stricken with sea sickness to such an extent that launch preparations were postponed by a few hours for the crew to recover.



Niels Foldager and Peter Madsen doing final avionics checkout during the September 5th 2010 launch attempt.


Launch preparations were then carried out, and 535 kg of liquid oxygen was transferred to the onboard LOX tank. Unfortunately, upon ignition of the engines onboard pyrotechnics, the valve between the LOX tank and the combustion chamber failed to open, and hence the launch had to be aborted and postponed.

2011 launch!
While waiting for the next possible launch window in the summer of 2011, several important upgrades were made. The most important upgrade was the installation of two diesel engines on Sputnik such that she is now self-propelled. In early June the entire team once again assembled in Spaceport Nexø, and on the morning of June 3rd we set out to launch HEAT-1X. Weather conditions were perfect, and despite a small error in the launch control system HEAT-1X rose beautifully from its platform, carrying the Tycho Brahe spacecraft.


LOX tank plastic insulation is ripped of as the rocket clears the tower.

HEAT-1X carrying Tycho Brahe rises from the launch platform at 15:32 on June 3rd 2011.


However, within the first few seconds the vehicle pitched over to fly at an angle of about 30 degrees to horizontal. As a consequence of the undesirable flight path the motor was shut down after 15 seconds at an altitude of 1,400 meter. The low flight angle inevitably lead to a high horizontal velocity at the moment of parachute deployment. This lead to parachute malfunction, and the booster impacted the water at a very high speed causing it to disintegrate and sink. The spacecraft landed with a single partially torn parachute deployed, causing significant damage. Despite being filled with water, the spacecraft kept afloat and was recovered by Recovery Alpha. For more information and analysis on the HEAT-1X/Tycho Brahe mission please refer to the post flight analysis report.


Shortly after lift off the vehicle pitched over to a 30 degree flight path which caused a manual engine shut down 15 seconds into the flight.


HEAT-1X legacy
The Copenhagen Suborbitals 2011 Launch Campaign was a tremendous success! CS has proven itself capable of building a 12 ton heavy mobile launch facility and launch a 1,630 kg, 9.38 meter tall rocket from sea. This is a milestone in CS’s program to reach manned suborbital spaceflight. Launching a rocket this size is however not only about technological ability. It is also about building up a strong organization which is recognized by authorities and partners as a serious project. Thus, both technological and organizational experience from the 2011 launch campaign will provide a solid platform for future launches.

The undesirable trajectory forced a premature motor shutdown. The shutdown was performed by radio control and the decision to do so was made based on downlinked trajectory information and real time trajectory extrapolation and impact prediction. It is the first time in amateur aviation and space flight history that a rocket flight is safely aborted in this way. This feature demonstrates CS’s commitment to range safety and safety to CS and other participating personnel.

The HEAT-1X/Tycho Brahe mission also lead to the foundation of Copenhagen Suborbitals Support, a foundation which today forms the economical basis of the entire project. In this way HEAT-1X has opened a world of possibilities to Copenhagen Suborbitals and for the entire crew that participated it was a truly mind blowing experience to be part of the world’s first amateur sea launch operation.