1. Field of the Invention
The present invention relates to protective equipment that is used to allow humans to safely and effectively work in environments with low atmospheric pressure (aircraft, sub-orbital spacecraft, environmental chambers, surface of Mars, etc.), or zero atmospheric pressure (space, vacuum chambers, surface of the moon, etc.).
2. Background of the Invention
Several approaches for protecting humans in low atmospheric to vacuum environments have been used or investigated for use for several decades. These include full pressure suits and mechanical counter-pressure suits. The goal of these suits is to protect the respiratory tract and provide pressure to all surfaces of the body to prevent the conversion of liquids in the body to gasses which would lead to loss of life. Full pressure suits are enclosures which surround the body and provide a pressurized atmosphere for protection. Mechanical counter-pressure suits consist of garments which physically compress the body, and a pressurized helmet which surrounds the head.
Full pressure suits have been used for altitude protection for pilots since the 1950s, and for space exploration since the 1960s. Pressurization of the suits to the minimal levels required to meet human physiological needs (Ex: Apollo space suits operated at 3.8 psid (pounds per square inch differential)1 pure oxygen) results in high joint torque with limited mobility, which causes fatigue and reduces performance. This is particularly critical in omnidirectional joints such as the shoulder, hips, or torso. Bearings and other rigid components can be added to the suits to reduce joint torque and enhance mobility but are heavy, costly, and not applicable to suits worn during flight in aircraft or during launch and entry of spacecraft. In the case of space exploration the addition of rigid components to space suits has a very negative impact on mission effectiveness and economics. The inability to wear the same space suit for launch/entry and for extravehicular activity (Ex: Space Shuttle paradigm) leads to a two suit system which is costly to develop and maintain, requires more launch mass, and has greater logistics and maintenance implications. 1The “differential” is between the pressure inside and outside of the suit. It is helpful when you talk about a suit's operation in differing pressure environments (zero-gravity, Mars' surface, high altitude, etc.). Saying a suit operates at, for example, 4.3 psi, doesn't mean much unless you know the external environmental pressure. This way the number is essentially normalized. This is standard practice in the industry.
Mechanical counter-pressure suits have been studied since the 1950s with the first being the Space Activity Suit, but no suit has ever been used operationally. These suits apply compression to the body through elastic textiles, or textiles that are tensioned through the use of pressurized subcomponents, or attached electromechanical devices such as shape memory alloys or electroactive polymers. The goal of development of the technology was to reduce joint torque and enhance mobility over full pressure suits. However, the mechanical counter-pressure suits have several drawbacks that prevent them from practical application. First, the application of the >3 psi pressure to the body is very uncomfortable and elevates blood pressure through compression of the entire vascular system, which yields an unsafe load on the heart. Also, some parts of the human anatomy don't like to be squeezed and pressure application can be painful. Second, it is very difficult to apply uniform and consistent pressure to all surfaces of the body during motion because of near flat contours and concavities on the human form.
Mechanical pressure has been found to have efficacy in medical and sports therapies at considerably lower pressures than the mechanical counter-pressure suits. Elastic textile sleeves that apply under 1 psi to major muscle groups are available commercially. Therapy devices do not require precise pressure application in comparison to that required by mechanical counter-pressure suits because the result of ineffective use is limited to less effective therapy as opposed to a dangerous evolution of gas under the skin that can become life threatening.
The limitations of full pressure suits and mechanical counter-pressure suits, in conjunction with a growing need for more economical solutions for applications such as space exploration with improved comfort and performance, has led to the development of the compression augmented full pressure suit system of the present disclosure.
The compression augmented full pressure suit combines the basic approach of full pressure suits and mechanical counter-pressure suits to create a hybrid with better economics and performance than either of the other solutions alone. The compression augmented full pressure suit is not just a simple hybridization of other suit technologies, but includes enhancement of the base approaches to meet performance needs. The compression augmented full pressure suit uses an enhanced compressive body stocking inside a full pressure suit so comfort and mobility are balanced while the body is safely protected from low atmospheric pressures. The inward applied pressure from the compression garment and the pressure the suit applies are additive and can be balanced (passively or actively) to yield the optimal suit system.
The full body stocking mechanically applies approximately 1-2 psi of pressure to the body via a specialized elastic garment similar to those used in sports medicine, but modified to provide a predictable pressure to all surfaces of the body including concave spaces. The elastic garment will include compliant components (Ex: molded foam or gel-filled bags) that fit into concavities, or on flat surfaces, on the body to convert them into convex shapes which can be compressed by the elastic garment such that it transmits its inward compression to the body over its entire surface. It is important to note that the elastic layer can't apply inward pressure on a flat surface and therefore features must be added to keep the elastic in a form as close to a cylinder as feasible to yield a consistent inward pressure. The compression garment preferably is undersized to the body of the wearer in order to apply pressure over the wearer's entire body. The use of the pads described below assures that such compression is also applied to flat and concave areas of the wearer's anatomy.
The full pressure suit will operate at approximately 2-4 psid, depending on the application. Full pressure suits that operate in this range are highly mobile and can be made with textile-based mobility joints to preclude a reliance on rigid mechanical elements such as bearings or rings to create mobility joints. The pressurized suit also provides a means for thermal control and the elimination of sweat from the body via air exchange. Thermal control is maintained by passive insulation applied over the full pressure suit and/or active thermal regulation such as liquid cooling which can be embedded directly into the compression garment or as a separate layer over the compression garment. The thermal regulation system approach is determined by the operational environment (pressure at altitude, vacuum in earth orbit or on the moon, the atmosphere of Mars, etc.).
The compression augmented full pressure suit is mostly compiled of soft flexible elements and is therefore comfortable enough to wear during launch and entry during space flight, but also mobile enough to meet the needs of the crew during emergency cabin depressurization, or use during extravehicular activity in zero gravity or on a planetary surface. The compression augmented full pressure suit is also comfortable and mobile enough to be used for aircraft or suborbital spacecraft that fly at high altitudes.
A helmet covers the head and is pressurized to the standard pressure of a space suit (˜4 psi with 100% oxygen) since no mechanical pressure could be effectively applied to the head. An elastomeric neck dam will provide the seal to the wearer's neck to separate the helmet volume from the suit volume so the helmet pressure can be maintained at a higher level than in the full-pressure suit. This allows the total suit pressure to be lower and therefore improve mobility which is key.
The compression augmented full pressure suit offers a form of safety and redundancy not available in current flight suits or space suits because it has 2 pressure application layers. In the event of loss of function of one layer, the other will provide limited protection to allow the crew to return to safety. Safety will be improved because of reduced operational pressure of the full pressure suit because the potential for burst or tear propagation will be reduced with a lower skin stress in the pressure vessel. The compression augmented full pressure suit also provides better medical safety than mechanical counter-pressure suit alone because it reduces blood pressure and load on heart from increased vascular compression over the entire body.
In extreme cases the amount of compression the compression garment applies, and the pressure at which the full pressure suit operates, can be actively controlled to provide full system redundancy in the event of failure of either component. This is achieved by increasing the pressure of the full pressure suit if the compression garment fails, or increasing the compression the compression garment applies if the full pressure suit fails. In this case the compression garment would include an active system such as capstan tubes that can be pressurized to control tension in the garment similarly to older anti G-suits, or integrated electroactive polymers that can be electronically controlled to increase compression. The addition of this redundancy will, however, add complex control systems and the need for power, so the need must outweigh the system impact.
The compression augmented full pressure suit has significant economic and logistical benefits over the current approach to space exploration because a single suit can be used in place of the two different suits used for launch/entry and extravehicular activity. The single suit system reduces development and manufacture cost, is lower mass and volume which reduces launch costs, reduces logistics through fewer parts to supply and maintain, and reduces crew maintenance time. Conversely, even in a two-suit system or in a scenario such as aircraft or sub-orbital spacecraft, the pressure augmented full pressure suit offers advantages over current suit technologies because it provides enhanced mobility at a reduced system cost.
As shown in
The full pressure suit 300 can be constructed from numerous existing components used in historical or current high altitude flight suits and space suits, or from new approaches which simplify construction. The limiting factor in the performance of these suits is always the mobility joint performance at operational pressure. Operating at a lower pressure enables the mobility joints to be simplified to the point of being unique, which is what is described here.
The full pressure suit component 300 of the compression augmented full pressure suit 100 is designed with low pressure mobility joints 302 (
The full-pressure suit 300 preferably includes a pressure-sealing zipper entry 309 for donning and doffing the suit. Several geometric configurations of zipper integration are possible because of the low operational pressure, and many have been incorporated in previous suits. The compression augmented full pressure suit contains a helical zipper entry at the waist that facilitates donning and doffing the suit while in a capsule. The upper 301 and lower halves 302 of the suit remain attached to one another by a strip of material (not shown) when open, but can be separated far enough to simplify entry and exit by the wearer. A separable pressure sealing zipper 310, 311 (similar to those used on jackets or Zip-Loc® bags), can also be used to facilitate complete separation of parts of the suit. This facilitates donning and doffing, but also reconfiguration of a suit with varying sized components to fit a large population with a controlled number of components. This strategy also allows the life of a suit to be extended beyond the life of its first component to become worn out.
The compression augmented full pressure suit 100 can be custom fitted or comprised of standard sized elements. Minimizing the volumetric difference between the full-pressure suit 300 and the wearer, and attaining proper fit, contributes to joint torque reduction and improved performance, so being able to properly size the suit to the wearer is a critical factor in achieving optimal utility in the suit. Lacing strips (
The full pressure suit has a helmet 306 that is connected to the upper torso 301 such that it closes the volume of the suit at the neck location, and restrains the loads from pressurization that try to lift the helmet 306 off the suit. The connection is separable so that the helmet can be worn without the suit for pre-breathing oxygen for bends' protection or, in some emergency situations including smoke or chemical exposure. The helmet 306 may contain a neck dam 307, which can be a separable element, or integral with the helmet 306, or upper torso portion 301, which creates a partition between the helmet volume and the suit volume, by sealing against the neck of the wearer. This facilitates the ability to have different pressures in the suit and helmet volumes. The pressure in the helmet 306 must be maintained at a level that accommodates the needs of human physiology. However, the suit pressure can be lower than the helmet pressure to enable greater mobility through a reduction in joint torque. Alternatively, the neck dam 307 can be provided as a separate component that interacts with the helmet 306 to permit the presence of different pressures in the suit from that supplied to the head of the wearer. A helmet 306 to suit 300 connection is provided at 308. Boot 304 to lower torso 302 connections are provided at 311. Similarly, glove 303 to upper torso 301 connections are provided at 310.
The compression garment is comprised of fibers (
A variety of compliant pads 201, 206-214, of different shapes and materials of construction, are strategically added to the compression garment 200 to fill the concavities on the body of the wearer (such as pads for the arm pits 208, small of the back 211, palm, groin 212, clavicles 207, back of the knee 214, elbow 209, buttocks 213 etc.), or reshape flat surfaces on the body, such as chest pad 206, upper back pad 210, lower back pad 211 to ensure uniform pressure application. They must move with the body so as to not limit motion, and not create “hot spots” that are uncomfortable. This is accomplished by making the pads from highly compliant materials such as gel-filled 216 bladders 215 (
Gel or liquid filled bladders (
Three dimensional pads made from elastomeric materials or foam are another approach, and are best suited to flat areas such as the back, particularly upper back pad 210 and lower back pad 211 as shown in
The compression garment 200 can be a single garment that covers the entire body, or it can be manufactured in multiple sections. The single garment would require a zipper which is possible but may lead to discomfort. The more practical approach is to manufacture the compression garments in multiple components (shirt or upper torso 201, gloves 203, pants or lower torso 202, socks 204) that are separable to facilitate simple donning/doffing, and logistical simplification through replacement of worn or damaged components such as gloves 203 that will wear our faster than shirts 201. Each of these sections of the compression garment 200 needs to be closely tailored to the geometry of the wearer with their associated pads 201. To accomplish this, the wearer is three-dimensionally scanned, the data is loaded into a computer aided design package, pads 201, 206-214 are added, and the three-dimensional form of the ideal garment is generated. Patterns or weaving paths are generated from this form, and are then used to construct the garment.
A unique feature of the compression garment 200 for the compression augmented full pressure suit 100 is that the garment 200 only needs to apply the required compression in one axis of the body. This increases material options for garment solutions and increases wearer comfort and performance. For example, the compression garment 200 on the leg only needs to apply force through tightening of the circumferential fibers 317. The longitudinal fibers 318 do not have to apply compression and can therefore be designed to facilitate movement. Therefore, weaves can be structured that apply circumferential pressure to the leg, but at the same time do not limit flex of the knee. This yields the greatest mobility possible through torque reduction of the joint.
In addition to the various weaves that can be employed in the compression garments, reduction in the number of individual full pressure suit components 300 that must be created for a particular crew or mission can be reduced by employing the sizing features illustrated in
Similarly, the compression garment 200 can incorporate multiple zippered or laced sections to alter the tension of the compression garment 200 on the wearer of the compression garment 200, of modify the size of the compression suit 200 (or a single component thereof) to accommodate the size of different wearers.
When viewed in environments of Mars exploration, or even extended space station activities, the provision of a fewer number of components that fit the body types of multiple different human forms is extremely desirable and reduces the need for custom or bespoke requirements of space suit production.
The compression garment 200 can be a simple passive garment that only applies the required compression to the skin, or it can be modified to include functionality. Examples of functionality can include thermal regulation (including tubes for carrying heated or cooled fluid or electrically heated conductors), biometric sensing, or performance monitoring. In some cases, a wire harness that carries power or signals from/to sensors to the life support system or other control devices, may be integrated directly into the garment itself by weaving in electronic textiles. Conductive fibers can be included in the weave patterns for this purpose. These fibers can be elastic in nature to stretch and conform similarly to the rest of the fibers in the compression garment, or can be inelastic and woven such that they have serpentine or zig-zag paths and do not limit the motion of the body as the whole garment changes shape. The electronic textiles can also be surface applied to the garment so as to be not directly integrated in the weave. Sensors, connectors, heaters, actuators, or even lights, can be attached to the electronic textiles to create the electronic network that forms the desired functionality.
It will be apparent to those persons skilled in the art, upon reading my description of the various embodiments described herein, that various modifications and alterations of the disclosed embodiments can be envisioned and implemented without departing from the scope and spirit of the appended claims.
This application is a Non-Provisional Patent Application which claims benefit of Provisional Patent Application Ser. No. 62/289,981, filed Feb. 2, 2016, the entire contents of which are herein incorporated by reference in its entirety and the priority of which is claimed under 35 U.S.C. §119.
Number | Date | Country | |
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62289981 | Feb 2016 | US |