A space suit and pressure helmet designed to protect Austrian skydiver Felix Baumgartner in his record-breaking 120,000ft (36,576m) free-fall attempt have been revealed to the public.
The space suit was designed by Red Bull Stratos and fabricated by air and space crew protective equipment manufacturer David Clark Company. This is the first space suit ever produced by David Clark Company for a non-governmental space programme.
The suit, along with a pressure helmet, will serve as Baumgartner’s sole life-support system when he steps off his capsule at 120,000ft to attempt a record-breaking free fall from the edge of space.
While there is currently no fixed date set for the attempt, it is expected to take place some time this summer, depending on weather conditions and the resolution of any remaining technical anomalies.
The full-pressure suit has been designed to protect Baumgartner as he travels through a hostile stratospheric environment with hazards including temperatures as cold as -56ºC in an environment with too little oxygen to sustain human life and air pressure so low that decompression sickness and ebullism – a condition in which blood ‘boils’ with life-threatening vapour bubbles – are pervasive dangers.
During his ascent beneath a 30 million cubic foot polyethylene balloon filled with helium, Baumgartner will depend on a sealed capsule to provide a pressurised environment. Once he depressurises the vessel and opens the door to step off, his full-pressure suit and helmet – what engineers call a ‘Pilot Protective Assembly’ or PPA – will be his only life-support system until he reaches the safety of the lower atmosphere.
By attempting to break the speed of sound in free fall, Baumgartner will be trailblazing a velocity that future astronauts and aviators may have to face. Although Baumgartner will need to optimise his flight posture to achieve Mach 1, astronauts bailing out from significantly higher altitudes would likely attain supersonic speed involuntarily.
Members of the Red Bull Stratos science team expect that the rigidity and protection of a full-pressure suit is necessary to provide benefits at such unprecedented speed, but using the protective assembly will also present challenges such as restricted mobility, vision constraints and some loss of tactile sensation.
The Red Bull Stratos full-pressure suit and helmet have been modelled on those developed by David Clark Company for pilots of high-altitude reconnaissance aircraft.
However, Baumgartner’s PPA was custom made to his measurements, and special modifications, including enhanced flexibility, have been incorporated to accommodate free-fall demands. It is believed his suit will serve as the prototype for next-generation pressure suits.
Mike Todd, the Red Bull Stratos life-support engineer, described Baumgartner’s PPA as ‘an artificial atmosphere’. The suit’s exterior is made of a material that is fire retardant and an insulator against extreme cold.
Inside, the ‘bladder’ (which will be filled with gases to provide pressurisation before Baumgartner exits the capsule) is composed of a selectively permeable material surrounded by link netting. When the bladder is inflated, it will provide pressure at 3.5psi (pounds per square inch) – sufficient to prevent the expansion caused by ebullism.
An integrated control valve, the ‘brains’ of the suit, maintains pressure automatically at various altitudes. The shell of the helmet is moulded from composite materials. Its visor, which is distortion free in the critical vision area, has an integrated heating circuit that must warm it enough to avert fogging and icing, yet not melt it. This function is doubly challenged by a stratospheric environment that lacks air to draw away heat and a potentially supersonic free fall that will encounter rapid changes in temperature. The helmet will also supply Baumgartner with 100 per cent oxygen (from cylinders he will wear) and it includes a microphone and earphones for communication with the Mission Control Centre.
Initial pressure-suit findings
While it is important to assess the pressure suit itself, the key to optimising its functionality lies in seeing how the suit works with the other mission components, including the parachute rig.
Low-pressure chamber: The integrity of the personal life-support system was confirmed, but, as with many astronauts and aviators, Baumgartner found the near-sensory deprivation of the suit unsettling and had to accustom himself to a feeling of isolation.
Wind-tunnel tests: The team was strongly encouraged to learn that when Baumgartner manoeuvred to the streamlined ’delta’ position, which he will use in his stratospheric free fall, instability minimised and airflow smoothed, despite the unaccustomed bulk of the suit.
25,000ft helicopter jumps: It was found that, as a result of the suit’s sensory limitations, Baumgartner could not easily distinguish the handles of his parachutes – a potentially dangerous situation. The parachute rig has since been modified to make the handles distinguishable by touch, even through the pressure-suit fabric, and mirrors have been added to Baumgartner’s gloves to enable him to see his equipment despite restricted vision in the helmet.
Source: Red Bull Stratos