Human missions to the moon and Mars will require more robust technologies than those used on the International Space Station (ISS). Life support and other systems will have to be more efficient and robust to ensure the safety of astronauts when these flights begin in the 2020’s.
NASA has been using the space station to test and improve key systems. However, the Trump Administration’s desire to end direct federal support for ISS in 2024 to free up funding for lunar flights could heave a number of key technologies untested, according to a recent NASA Inspector General audit.
Below is an excerpt from the report that discusses the technology demonstrations being conducted on the space station and the risks involved of ending station support in 2024.
NASA’s Management and Utilization of the International Space Station
Office of Inspector General
July 30, 2018
In addition to conducting research on human health risks, NASA also undertakes technology demonstrations that need to occur on-orbit to aid in the development of exploration systems for missions to the Moon or Mars. In 2013, the Agency created 14 System Maturation Teams to address specific technology capability areas such as propulsion and life support systems required for NASA to undertake its long-term human exploration goals. In turn, NASA uses the work of these teams to prioritize its technology development investments. In addition, the ISS Program coordinates with the teams to perform technology demonstrations, including tests of thermal control systems, air and carbon dioxide monitoring, and waste purification systems.
In 2017, the ISS Division, which provides strategic guidance to the ISS Program, compiled an “ISS Technology Demonstration Plan” to track capability gaps that must be closed to enable long-duration space missions. The plan shows the dates of in-development and proposed demonstration flights on the ISS. The capability gaps are denoted in dark blue with their associated technologies listed below them. Triangles indicate anticipated launch dates with colors denoting whether the demonstration is currently on-orbit, in development, or proposed and not yet approved. The Agency updated the plan most recently in January 2018 (see Figure 5).
Not all Human Health Risks and Technology Gaps
will be Addressed by 2024
Despite NASA’s efforts, multiple human health risks and technology gaps will remain after the end of FY 2024 when funding for the Station’s operation is scheduled to end….[T]he Agency’s ISS Technology Demonstration Plan estimates that 4 of 40 technology demonstration gaps will not be completed by 2024. In addition, we found that another 17 technology gaps could be at risk due to schedule slippage because their completion dates are throughout 2024. Furthermore, the Agency’s Integrated Path to Risk Reduction and Technology Demonstration plans assume steady progress in reducing the risks; however, the plans have undergone several revisions since their inception that often push out the schedules for certain risks and demonstrations.23
Technology Demonstration Capability Gaps
Research on the 21 technology demonstration capability gaps scheduled to be completed in FY 2024 or later include technologies related to environmental control and life support; environmental monitoring, safety, and emergency response; extravehicular activity; human health and performance; communications, navigation, and networking; and in-space manufacturing. Although the Technology Demonstration Plan projects these gaps will be largely complete by the end of 2024, the Agency has little schedule margin to absorb delays.
To the point, the NASA Advisory Committee noted in July 2017 that “while projections show that the work should be complete by 2024, the committee believes that it is likely that exploration development work on the ISS will need to be continued until 2028 or later.” In addition, the leaders of several of the capability gap teams we spoke with expressed skepticism on projected funding and suggested that demonstrations likely would continue after 2024 because many of these systems require on-orbit runtimes of one year or longer to collect sufficient data.
Although the Agency may be able to find alternate testing platforms for some of these technologies, 14 gaps in the environmental control and life support and extravehicular activity areas will require extensive testing aboard the ISS due to the unique impact of microgravity on fluid dynamics (see Figure 7).
Furthermore, while NASA has developed preliminary plans for alternate testing platforms, the Agency has not created detailed contingency plans that would address factors such as cost, schedule, and technical risks that would exist if the Agency was required to rely on alternate platforms instead of the ISS.
Environmental Control and Life Support
One of the key areas that will require the ISS for testing through 2024 or later is the development of technologies for future space‐based environmental control and life support systems. The Agency’s ISS Technology Demonstration Plan projects that 10 of 11 environmental control and life support technologies that require testing on the ISS are not expected to be complete until the end of 2024 or later. NASA officials said this timetable is due in part to the demonstrations not having funding priority until recently. Furthermore, some of the experiments require multiple years to test on the ISS.
The Agency is working to develop or improve technologies for carbon dioxide removal, urine and water processing, water and oxygen recovery, and dust filtration. Each of these technologies is critical because future deep space exploration missions will not have the ability to regularly resupply necessities such as oxygen and water. Current systems on the ISS have a 42 percent oxygen and 90 percent water recovery capability, which will need to be improved to at least 75 percent oxygen recovery and 98 percent water recovery for long duration missions (see Figure 8).
Furthermore, some components of the ISS’s environmental control and life support system have an average life span of less than six months before expected failure, requiring regular replacements using cargo resupply flights from Earth. Future systems will require technologies that can last more than 30 months before failure. NASA officials said it is critical to test these technologies on the ISS because fluid systems behave differently in microgravity compared to Earth. The officials further stated that if the demonstrations are not completed prior to 2024, testing could continue on the ground but with higher risk of not understanding system performance and failure rates in the relevant environment.
Exploration Extravehicular Mobility Unit Demonstration
Another key technology demonstration area that will require the ISS for testing through 2024 or later is the development of an exploration extravehicular mobility unit, more commonly known as a spacesuit. Although the spacesuit currently used on the ISS for extravehicular activities (spacewalks) is suitable for operations in low Earth orbit, it does not offer the mobility, durability, or functionality planetary or cislunar missions will require.28
The Agency is currently developing an advanced portable life support system that provides air to the spacesuit and is connected to a hard upper torso, which is worn over the astronaut’s chest (see Figure 9). The ISS Technology Demonstration Plan schedule projects the Agency will not begin testing the advanced spacesuit on-orbit until the end of FY 2024 and will not complete testing until the end of FY 2025.
As we reported in April 2017, NASA’s spacesuit development efforts have struggled from a lack of operational requirements, stable funding, and stable plans.29 NASA officials stressed that testing of the suit’s portable life support system in microgravity is critical to developing the spacesuit. Without adequate microgravity testing, NASA will need to accept higher levels of risk during future exploration missions, potentially impacting astronaut health and safety as well as mission success.
23 We did not independently review the progress being made in each human health and technology demonstration area in this audit.
28 Cislunar space is the area between Earth and the Moon or the Moon’s orbit.
29 NASA OIG, “NASA’s Management and Development of Spacesuits” (IG-17-018, April 26, 2017).