Long Duration Sorbent Testbed (LDST) - 01.16.19

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Exposure to space cabin environments can change the way materials behave, which can affect the performance of products designed to filter and clean air and water. Previous observation has shown desiccants, which collect humidity from the air to keep materials dry, can be up to 75 percent less effective after functioning one year in a space habitat. The Long Duration Sorbent Testbed (LDST) investigation studies substances that collect other molecules, determining which types would be most effective on long-term missions to Mars or other destinations.
Science Results for Everyone
Information Pending

The following content was provided by Jim Knox, and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom: Long Duration Sorbent Testbed

Principal Investigator(s)
Jim Knox, MSFC, Huntsville, AL, United States

Information Pending

NASA Marshall Space Flight Center, Huntsville, AL, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Technology Demonstration Office (TDO)

Research Benefits
Space Exploration

ISS Expedition Duration
March 2016 - February 2018

Expeditions Assigned

Previous Missions

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Experiment Description

Research Overview

  • The Long Duration Sorbent Testbed (LDST) investigation exposes desiccants and CO2 sorbents to the ISS atmosphere for an extended period (such as one year) before returning them to earth for analysis of contamination level and capacity loss.
  • The subscale payload approximates ISS CDRA operation via adsorption and heated desorption cycles.
  • A parallel ground test would determine if the effect of the ISS atmosphere on sorbents can be accurately simulated on earth.
  • Emerging sorbents have attractive capacity and low dusting potential, yet may lack long duration chemical stability in a spacecraft atmosphere.
  • LDST provides early material assessments, (1) guiding selection of sorbents and (2) providing end-of-life performance estimates.
  • Sorbent selection and long-life performance are both critical to the successful design of CO2 Removal Systems for Exploration missions.

NASA Roadmaps specify increased robustness/reliability of life support systems for Exploration (TA06). The Long Duration Sorbent Testbed (LDST) investigation provides early material assessments, (1) guiding selection of sorbents and (2) providing end-of-life performance estimates. Both are critical to the successful design of CO2 Removal Systems for Exploration missions. This payload complements on-going ISS and AES-funded tasks aim at characterizing physical durability and performance of sorbents and desiccants under operational and environmental conditions such as thermal cycles, humidity, and airborne contaminants (focus of this experiment).

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Space Applications
Sorbents are materials that can collect other molecules through adsorption, and are used to keep products dry or to collect gases. Previous experiments have shown some sorbents lose effectiveness after being used in space for a year, which could pose problems for crews on long-duration missions to Mars, where replenished supplies would not be possible. This investigation studies how operating in a space habitat weakens the adsorption capacity of different sorbents that are being considered for use in future missions.

Earth Applications
Many electronics and other new items are packaged with a small packet of desiccant, which traps moisture and protects the products. Understanding how the materials degrade over long durations and in harsh environments benefits manufacturers and consumers on Earth.

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Operational Requirements and Protocols

LDST launches in an ISS Locker, is soft stowed, and installed on-orbit in an EXPRESS Rack. LDST is activated and runs autonomously for approximately one year. During the experiment run, a weekly status check by the crew may be requested. Every two months the Inlet Filter should be changed out. The removed Inlet Filter should be trashed. After scientific objectives are completed, the entire payload returns for sample analysis. LDST has no Orbital Replacement Units (ORUs), no sample change-outs, and no expected crew maintenance.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites

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Long Duration Sorbent Testbed (LDST) Locker.

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NASA Image: ISS050E053932 - Long Duration Sorbent Testbed (LDST) during Inlet Filter change, Part Number (P/N): LDST-ES62-1000, Serial Number (S/N): 001, Barcode: 00221351M - JPM1F1_F2. Photo taken during Expedition 50.

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