Search Results

The National Aeronautics and Space Administration's (NASA) planned future missions set stringent demands on the design of the Portable Life Support System (PLSS), requiring dramatic reductions in weight, decreased reliance on supplies and greater flexibility for Extravehicular Activity (EVA) duration and objectives. Use of regenerable systems that reduce weight and volume of the space suit life support system is of critical importance to NASA, both for low orbit operations and for long duration manned missions. The carbon dioxide and humidity control unit in the existing PLSS design is relatively large, since it has to remove and store eight hours worth of carbon dioxide (CO2). If the sorbent regeneration can be carried out during the EVA with a relatively high regeneration frequency, the size of the sorbent canister and weight can be significantly reduced.

TDA Research, Inc. (TDA) is developing a compact, lightweight ExtraVehicular activity (EVA) emergency system that provides 30-minute life-support in the case of system or component failures in the Portable Life Support System (PLSS). The system uses a low ventilation rate to reduce the amount of stored oxygen, reducing the associated weight and volume penalty. Operation of the system requires an effective sorbent that would remove carbon dioxide and moisture from the suit. We are developing a regenerable sorbent that is suitable for the conceptual system. Recently, we tested the sorbent performance in an adiabatic reactor setup simulating representative EVA emergency conditions. This paper summarizes results of these adiabatic tests.

The recovery of oxygen from a concentrated stream of carbon dioxide (CO2) offers significant advantage to long duration manned space missions by reducing the requirement for consumables. TDA Research, Inc. (TDA) is developing a chemical absorbent-based system to carry out CO2 removal and CO2 reduction for the Environmental Control and Life Support System (ECLSS) at the International Space Station (ISS). The system eliminates the interfacing problems associated with the currently operational CO2 Removal Assembly (CDRA) and planned CO2 Reduction Assembly (CRA). This paper discusses the development efforts of a regenerable absorbent that is suitable for our conceptual system recommended for future missions. We also tested the performance of a state-of-the-art catalyst for CO2 reduction to water and methane at the conditions of interest. We demonstrate the technical feasibility of carrying out CO2 removal and reduction.

The selection of technologies for an evolutionary Space Station Freedom or a planetary (lunar or Martian) extravehicular mobility unit (EMU) are strongly driven by the system volume and weight as well as life cycle costs, reliability and safety. TDA Research, Inc. (TDA) is developing a compact, lightweight emergency system that provides 30-minute life-support in the case of system or component failures in the Portable Life Support System (PLSS). The system uses a low ventilation rate to reduce the amount of stored oxygen, reducing the associated weight and volume penalty. Operation of the system requires an effective sorbent that would remove carbon dioxide and moisture from the suit. We developed a regenerable sorbent that is suitable for the conceptual system. We also carried out a preliminary system analysis to show that the design saves significant weight.

With an increased rate and length of extravehicular activities (EVAs), a low, but statistically significant possibility exists for system and component failures. In that potential event, it is critical to provide oxygen support, carbon dioxide and moisture removal and thermal control to sustain life. The existing EVA emergency system in the Portable Life Support Unit (PLSS) is reliable, and works well, however, it is heavy because of the high oxygen consumption inherent in its open-loop mode of operation. TDA Research, Inc. (TDA) is developing a low-venting emergency system that provides 30-minute life-support in the case of system or component failures in the Portable Life Support System (PLSS). The approach is to minimize the quantity of the gas vented from the suit and thereby to reduce the weight of the stored oxygen. The operation of the system however, requires an effective sorbent that would remove carbon dioxide from the suit. TDA has developed such a sorbent.

The development of a portable diode laser based gas sensor and its application to sensitive, selective, on-line monitoring of formaldehyde concentrations present in a catalytic Trace Contaminant Control System (TCCS) in a 5-day period in August 1999 is reported. The TCCS was originally developed for the Lunar-Mars Life Support Test program in 1996-1997 at NASA-JSC. The motivation for monitoring H2CO levels in a sealed human rated environment is that its presence can cause headaches, throat and ear irritation at low concentrations (>100 ppb), and more serious adverse effects at higher concentration levels. Consequently, NASA has established a spacecraft maximum allowable H2CO concentration of 40 ppb for crew exposure for a 7 to 180 days period [1].