Tycho Deep Space II is the third generation space capsule, based on lessons learned and technology transfer from previous Copenhagen Suborbitals space capsules, and the final suborbital mission scenario. TDSII is a space capsule holding one person on a suborbital trajectory above the Karman-line. The capsule will be launched at sea on a Copenhagen Suborbitals mobile launch platform, Sputnik, flown into space and perform a splashdown at sea. Total air time is estimated to be approximately 20 minutes. It will be launched on HEAT-1600, the largest rocket ever build by amateurs.
Just like the previous capsule, TDSII will be fitted with a Launch Escape System. The concept is sketched below.
TDSII will utilize a Kazbek style seat for the astronaut who will also wear a pressure suit as a precaution against pressure breach of the hull. Subsystems and their placement on the capsule can be seen on the sketch below.
The main structure of TDSII is divided into two sections. The lower section (Crew section) which is the pressurized volume for the astronaut with seat, hatch, internal and external control panels and the majority of the avionic systems. The top section (Recovery section) which is an unpressurized volume containing uprighting systems, parachutes, reaction control system and LES-mounting.
The two sections will be produced separately and stacked for final assembly of TDSII using the flat flanges of each section and a series of large bolts. The top of the lower pressurized volume is a part of the upper section. Dividing TDSII is done to ease the development process and to provide a large hole (top of the pressurized volume) for seat installation and removal, as well as eased ingress for general electronic and avionics installation and testing.
The pressurized volume is composed of a lower Ø1600 mm convex disc (re-entry shield) and cone side plates with a height of 1100 mm. The side plates are attached the approx. Ø1000 mm top flange used for recover-section attachment. The interior walls must be added structures to withstand the internal pressure. These structures are 8×80 mm ribs welded to the interior wall. So far, FEM analysis is still being performed to validate the performance. The pressurized geometry is only breached for the hatch and the external control panels. The external control panels are placed on one side only, app 90 degrees from the hatch. The pressurized volumes must be finally checked for leaks and 1.5 bars overpressure before flight.
Note: So far, the interior pressure used for the flight is 1 bar. This is done to create an easy hatch-close to flight procedure, without having to lower the pressure. Also, a lowered internal pressure poses a serious problem for the inward opening hatch, which is designed to work from delta pressure 0-1 bar until the capsule reaches flight attitude with equal outside pressure.
The recovery section consist of a convex disc (top for the pressurized volume) attached the large assembly flange. On top of the convex disc an Ø600×800 mm parachute module is added. From the assembly flange and up along the parachute module, rib dividers are placed for uprighting bag installation, high pressure air for the RCS and external cameras. The top of the rib dividers are used for LES Tower installation. The sides of the recovery section will be produced as a rib structure with not finally welded sides. Instead cover plates will be added using blind rivets or bolts. This will make installation and maintenance easier. The cover plates must be able to withstand aerodynamic forces during flight, and impact forces during splashdown.
The seat is a vital component for the flight, providing a safe and comfortable place for the astronaut throughout the entire ride. The overall design of the seat is inspired by the Soyuz Kazbek seat providing the least volumetric use for this function. The person will be having feet close to the buttocks and knees maximum bent. This subsystem must provide easy access to the hatch, control panels and good hatch outlook and must provide astronaut attitude orientation in accordance to the accelerations during the launch, re-entry and splashdown. The mainframe of the seat is aluminium laser cut ribs holding a glass fibre mould fitting the ergonomics of the astronaut. The mould will be added soft foam fabric for comfort and the ribs will be added wire rope insulators to obtain general vibrations and oscillations. The seat is mounted on to the interior structure of the pressurised volume.
Uprighting makes sure that the capsule maintains a correct attitude in water, post splashdown. It is important to get the hatch above water and the astronaut in a correct position. It might take hours for the recovery crew to find the capsule and you need to be in a safe position, even for a solo emergency egress at sea. Uprighting can be performed using deployment uprighting bags and capsule mass shift (astronaut movement, flooding). A previous uprighting system was created using custom made PVC bags, solenoid valves and SodaStream CO2 flasks. The system is activated by data/radio command but can also be activated by water exposure. For TDSII the idea is to flood an internal independent 300 liter chamber to create a mass center shift combined with 3 uprighting bags. The complete sequence can be seen in the image below.
Under Development and construction
As TDSII is the current man-sized capsule project at CS many details are yet to be deisgned and decided upon. Thus, this page will be updated with relevant news as they develop.