Generally speaking, companies developing suborbital manned vehicles brag about how much elbow room their spacecraft will provide passengers. They say there will be plenty of room to float around during the weightless portion of the flight, that there will be no fighting for windows, that passengers will comfortably endure the high-g portions of the flight ... and then there's Copenhagen Suborbitals' (CS) Tycho Brahe.

CS takes a different approach toward the whole challenge of suborbital flight. Founded in 2008 by Kristian von Bengtson and Peter Madsen, CS is working with the stated goal of showing how space flight can be done outside governments and large corporations. The emphasis of the group is simplicity - using the simplest possible solutions which depend on technologies requiring little if any government paperwork.

Funding what is in essence a group of (highly skilled) amateur rocket scientists is also an exercise in simplicity. Operating funds are obtained through donations and sponsorships. Presently over 2000 people have donated to CS. Materials and equipment are also in large part donated, and the 20-odd team members are all volunteers. The activities of CS are open source, and all information and plans are also available to the public. To date, roughly US$300K has been spent over the past four years of extremely active development.

CS's Tycho Brahe is a one-passenger capsule intended for a purely ballistic flight to a peak altitude approaching 100 miles. The passenger is just along for the ride, with no mechanism to steer or otherwise pilot the capsule. Were it not for the transparent hemisphere (a plastic fishbowl) surrounding the passenger's head, the capsule would certainly be called claustrophobic, with a launch weight of 300 kg (660 lbs), a diameter of 0.62 m (2.03 feet), a capsule length of 3.5 m (11.5 feet) and a "cabin" length of 2.3 m (7.5 feet).

The crash test dummy (called "Randy" ... not "Buster") used for the initial flights has an average adult male build and a weight of 70 kg (154 lbs). The hull of the capsule and rocket are inexpensive - made from rolled-up two-meter wide steel plate, which is a standard size in Copenhagen. The internal atmosphere of the capsule is Earth atmosphere at one bar pressure.

Cross-section of the Tycho Brahe suborbital passenger capsule (Photo: Copenhagen Suborbitals)

As can be seen in the cross-section above, the passenger capsule is well packed with equipment. The passenger can only move their arms and turn their head slightly and spend the entire duration of the flight in a semi-standing position (people are particularly sensitive to accelerations experienced vertically, as blood pools in the lower extremities and leaves the brain somewhat starved of oxygen).

Engineering sketch for the passenger support of the Tycho Brahe. The nearly standing vertical position of the seat is accommodated through the use of anti-g leg bladders during periods of large acceleration (Photo: Copenhagen Suborbitals)

This seemingly uncomfortable ride position is partially offset by the design of the acceleration couch, which comprises an aluminum frame covered in memory foam, then covered with a fine leather outer layer. In addition to the cushioning effect of the memory foam the support forces a slight bend of the legs and thighs, thereby greatly reducing the loads on the knees, hips, and ankles. The passenger is equipped with anti-g bladders which squeeze the legs during periods of large acceleration. The downside - Tycho Brahe's astronauts will not be able to sample floating in zero-gravity, as it will not be possible for them to move around.

Externally, the Tycho Brahe has an aerospike to improve the supersonic aerodynamic performance of the capsule. Communications with the ground use two downlink transmitters and one uplink transmitter. Tracking of the capsule is facilitated by a 10.5 gigahertz transponder that sends a tracking signal to a portable tracking system near the launch vehicle.

10.5 GHz mobile radio tracking equipment (Photo: Copenhagen Suborbitals)

After the weightless part of the flight is ended, the Tycho Brahe has a heat shield which consists of multiple layers of cork tiles wrapped around the capsule to a total thickness of 15 mm (0.59 inches). The capsule has one drogue and three cross-shaped main parachutes for recovery, with a total area of 145 sq m (1560 sq ft). If something goes amiss, the passenger is also equipped with a personal parachute for "panic egress".

Next on the boards for CS is continued testing of the Tycho Brahe and its launch system, as well as ongoing development of the Tycho Deep Space, an orbital vehicle similar to a half-scale Apollo capsule, for which a more powerful launch rocket is being developed. A date for the first manned flight of the Tycho Brahe has not yet been set, but the astronaut will be Peter Madsen, co-founder of CS.

Copenhagen Suborbital's quest for private, inexpensive space flight may appear a terribly risky gamble to the casual outsider. However, like so many things, risk and reward balances are in the eye of the beholder. As one of the founders, Kristian von Bengtson, said this on his blog: "Is it better to die old and senile, or to die at 150 km with a big smile on your face?"

For myself, I can only say that if I lived in Denmark, I would run out to their main site and join in their effort.

The video below shows the 2011 test launch of the Tycho Brahe.

Source: Copenhagen Suborbitals