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By European Space Agency
A key element of ESA’s role as Europe’s space agency is the expansion of space knowhow, by encouraging new actors into the field. Case in point: a Polish software company previously specialising in smartphone apps took on the challenge of designing the operating system for the main instrument of Proba-3 – an ambitious double spacecraft mission to reveal secrets of the Sun’s fiery atmosphere, the corona.
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By NASA
This article is from the 2024 Technical Update.
The NESC evaluated material compatibility of some common aerospace metals in monomethylhydrazine (MMH) and nitrogen tetroxide (MON-3). Previous work had identified a lack of quantitative compatibility data for nickel alloy 718, 300 series stainless steel, and titanium Ti-6Al-4V in MMH and MON-3 to support the use of zero-failure-tolerant, thin-walled pressure barriers in these propellants. Static (i.e., not flowing) general corrosion and electrochemistry testing was conducted, evaluating varied processing forms and heat treatment of the metals, water content of propellant, and exposure duration. Corrosion-rate data for all tested product forms, fluids, and durations were on the order of 1 x 10–6 inch per year rather than the previously documented “less than 1 x 10–3 inch per year”. The majority of the corrosion products were seen in the first 20 days of exposure, with an overall corrosion rate decreasing with time due to the increased divisor (time). It is therefore recommended that corrosion testing be performed at multiple short-term durations to inform the need for longer-duration testing.
Background
Nickel alloy 718, 300 series stainless steel, and Ti-6Al-4V are commonly used in storable propulsion systems (i.e., MMH/MON-3), but a concern was raised regarding what quantitative compatibility data were available for proposed zero-failure-tolerant, thin-walled (~0.005 to 0.010 inch thickness) pressure barrier designs. A literature search found that limited and conflicting data were available for commonly used aerospace metals in MMH and MON-3. For example, corrosion behavior was listed qualitatively (e.g., “A” rating), data on materials and fluids tested were imprecise, fluids were identified as contaminated without describing how they were contaminated, no compatibility data were found on relevant geometry specimens (i.e., very thin-walled or convoluted), and limited data were available to quantify differences between tested materials and flight components. When corrosion data were quantified, documented sensitivity was “1 x 10–3 inch per year or less”, which is insufficient for assessing long-duration, thin-walled, flight-weight applications.
Discussion
General corrosion testing was performed with a static/non-flowing configuration based on NASA-STD-6001, Test 15 [1]. Design of experiments methods were used to develop a test matrix varying material, propellant, propellant water content, and tested duration. Materials tested were nickel alloy 718 (solution annealed sheet, aged sheet, aged/welded sheet, and hydroformed bellows), 300 series stainless steel (low carbon sheet, titanium stabilized sheet, and hydroformed bellows), and Ti 6Al-4V sheet. Samples were tested in sealed test tubes in MMH and MON-3 with water content ranging from as-received (“dry”) up to specification allowable limits [2,3]. Tested durations ranged from 20 to 365 days. Measurements included inductively coupled plasma mass spectrometry (ICPMS) to identify corrosion products and their concentrations in test fluid, gravimetric (i.e., scale) measurements pre- and post-exposure, and visual inspection. Bimetallic pairs (titanium stabilized 300 series stainless steel: Ti 6Al-4V and nickel alloy 718: Ti 6Al-4V) were tested for up to 65 days in both MMH and MON-3. The test setup incorporated important features of the test standard (e.g., electrode spacing and finish) and adapted the configuration for MMH/MON-3 operation. Measurements included potential difference and current flow between samples. Figure 1 shows images of the general corrosion and bimetallic pair test setups.
Test Results
For all tested materials and product forms, corrosion rates were on the order of 1 x 10–6 inch per year in MMH or MON-3, three orders of magnitude lower than historically reported. Corrosion products were generated in the first 20 days of exposure, and corrosion rate decreased with time due to the increase in divisor (i.e., time). Corrosion products increased as the water content of the propellants increased but remained in the same order of magnitude between the as-received dry propellant and propellant containing the maximum water content allowed by specification. Figure 2 illustrates test results for corrosion rate, mass loss with duration, and mass loss with water content. It is important to note that water has been demonstrated to contribute to flow decay even when water is within the specification allowable limit, and previous NASA-STD-6001 Test 15 data have demonstrated susceptibility of some nickel alloys to crevice-type corrosion attack [4]. Therefore, these results do not reduce the importance of considering the system impact of water content and evaluating for crevice corrosion behavior. Finally, in the bimetallic pair testing, tested materials did not measurably corrode in MON-3 and MMH within specification-allowable water content, as evidenced by no visual indications of corrosion and very low electrical interaction (i.e., corrosion rates derived to be less than 1 microinch per year from electrical interaction).
Recommendations
It is recommended that corrosion testing be performed at multiple shortterm durations to inform the need for longer-duration testing.
References
NASA-STD-6001 Flammability, Odor, Offgassing, and Compatibility Requirements
and Test Procedures for Materials In Environments that Support Combustion MIL-PRF-27404 Performance Specification: Propellant, Monomethylhydrazine MIL-PRF-26539 Performance Specification: Propellants, Dinitrogen Tetroxide WSTF Test 15 Report 12-45708 and WSTF Test 15 Report 13-46207 View the full article
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By Space Force
Over the past two years, the first U.S. space service component has tripled in size, established a 24/7 space watch cell and executed three Tier 1 Combatant Command exercises.
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By NASA
NASA astronaut and Expedition 72 Flight Engineer Nick Hague pedals on the Cycle Ergometer with Vibration Isolation and Stabilization (CEVIS), an exercise cycle located aboard the International Space Station’s Destiny laboratory module. CEVIS provides aerobic and cardiovascular conditioning through recumbent (leaning back position) or upright cycling activities.NASA Lee esta historia en español aquí.
The International Space Station is humanity’s home in space and a research station orbiting about 250 miles above the Earth. NASA and its international partners have maintained a continuous human presence aboard the space station for more than 24 years, conducting research that is not possible on Earth.
The people living and working aboard the microgravity laboratory also are part of the research being conducted, helping to address complex human health issues on Earth and prepare humanity for travel farther than ever before, including the Moon and Mars.
Here are a few frequently asked questions about how NASA and its team of medical physicians, psychologists, nutritionists, exercise scientists, and other specialized caretakers ensure astronauts’ health and fitness aboard the orbiting laboratory.
How long is a typical stay aboard the International Space Station?
A typical mission to the International Space Station lasts about six months, but can vary based on visiting spacecraft schedules, mission priorities, and other factors. NASA astronauts also have remained aboard the space station for longer periods of time. These are known as long-duration missions, and previous missions have given NASA volumes of data about long-term spaceflight and its effects on the human body, which the agency applies to any crewed mission.
During long-duration missions, NASA’s team of medical professionals focus on optimizing astronauts’ physical and behavioral health and their performance to help ensure mission success. These efforts also are helping NASA prepare for future human missions to the Moon, Mars, and beyond.
How does NASA keep astronauts healthy while in space?
NASA has a team of medical doctors, psychologists, and others on the ground dedicated to supporting the health and well-being of astronauts before, during, and after each space mission. NASA assigns physicians with specialized training in space medicine, called flight surgeons, to each crew once named to a mission. Flight surgeons oversee the health care and medical training as crew members prepare for their mission, and they monitor the crew’s health before, during, and after their mission to the space station.
How does NASA support its astronauts’ mental and emotional well-being while in space?
The NASA behavioral health team provides individually determined psychological support services for crew members and their families during each mission. Ensuring astronauts can thrive in extreme environments starts as early as the astronaut selection process, in which applicants are evaluated on competencies such as adaptability and resilience. Astronauts receive extensive training to help them use self-assessment tools and treatments to manage their behavioral health. NASA also provides training in expeditionary skills to prepare every astronaut for missions on important competencies, such as self-care and team care, communication, and leadership and followership skills.
To help maintain motivation and morale aboard the space station, astronauts can email, call, and video conference with their family and friends, receive crew care packages aboard NASA’s cargo resupply missions, and teleconference with a psychologist, if needed.
How does microgravity affect astronaut physical health?
In microgravity, without the continuous load of Earth’s gravity, there are many changes to the human body. NASA understands many of the human system responses to the space environment, including adaptations to bone density, muscle, sensory-motor, and cardiovascular health, but there is still much to learn. These spaceflight effects vary from astronaut to astronaut, so NASA flight surgeons regularly monitor each crew member’s health during a mission and individualize diet and fitness routines to prioritize health and fitness while in space.
Why do astronauts exercise in space?
Each astronaut aboard the orbiting laboratory engages in specifically designed, Earth-like exercise plans. To maintain their strength and endurance, crew members are scheduled for two and a half hours of daily exercise to support muscle, bone, aerobic, and sensorimotor health. Current equipment onboard the space station includes the ARED (Advanced Resistive Exercise Device), which mimics weightlifting; a treadmill, called T2; and the CEVIS (Cycle Ergometer with Vibration Isolation and Stabilization System) for cardiovascular exercise.
What roles do food and nutrition play in supporting astronaut health?
Nutrition plays a critical role in maintaining an astronaut’s health and optimal performance before, during, and after their mission. Food also plays a psychosocial role during an astronaut’s long-duration stay aboard the space station. Experts working in NASA’s Space Food Systems Laboratory at the agency’s Johnson Space Center in Houston develop foods that are nutritious and appetizing. Crew members also have the opportunity to supplement the menu with personal favorites and off-the-shelf items, which can provide a taste of home.
NASA astronaut and Expedition 71 Flight Engineer Tracy C. Dyson is pictured in the galley aboard the International Space Station’s Unity module showing off food packets from JAXA (Japan Aerospace Exploration Agency).NASA How does NASA know whether astronauts are getting the proper nutrients?
NASA’s nutritional biochemistry dietitians and scientists determine the nutrients (vitamins, minerals, calories) the astronauts require while in space. This team tracks what each crew member eats through a tablet-based tracking program, which each astronaut completes daily. The data from the app is sent to the dietitians weekly to monitor dietary intake. Analyzing astronaut blood and urine samples taken before, during, and after space missions is a crucial part of studying how their bodies respond to the unique conditions of spaceflight. These samples provide valuable insight into how each astronaut adapts to microgravity, radiation, and other factors that affect human physiology in space.
How do astronauts train to work together while in space?
In addition to technical training, astronauts participate in team skills training. They learn effective group living skills and how to look out for and support one another. Due to its remote and isolated nature, long-duration spaceflight can make teamwork difficult. Astronauts must maintain situational awareness and implement the flight program in an ever-changing environment. Therefore, effective communication is critical when working as a team aboard station and with multiple support teams on the ground. Astronauts also need to be able to communicate complex information to people with different professional backgrounds. Ultimately, astronauts are people living and working together aboard the station and must be able to do a highly technical job and resolve any interpersonal issues that might arise.
What happens if there is a medical emergency on the space station?
All astronauts undergo medical training and have regular contact with a team of doctors closely monitoring their health on the ground. NASA also maintains a robust pharmacy and a suite of medical equipment onboard the space station to treat various conditions and injuries. If a medical emergency requires a return to Earth, the crew will return in the spacecraft they launched aboard to receive urgent medical care on the ground.
Expedition 69 NASA astronaut Frank Rubio is seen resting and talking with NASA ISS Program Manager Joel Montalbano, kneeling left, NASA Flight Surgeon Josef Schmid, red hat, and NASA Chief of the Astronaut Office Joe Acaba, outside the Soyuz MS-23 spacecraft after he landed with Roscosmos cosmonauts Sergey Prokopyev and Dmitri Petelin in a remote area near the town of Zhezkazgan, Kazakhstan on Wednesday, Sept. 27, 2023.NASA/Bill Ingalls Learn more about NASA’s Human Health and Performance Directorate at:
www.nasa.gov/hhp
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By NASA
Media are invited to learn about a unique series of flight tests happening in Virginia in partnership between NASA and GE Aerospace that aim to help the aviation industry better understand contrails and their impact on the Earth’s climate. Contrails are the lines of clouds that can be created by high-flying aircraft, but they may have an unseen effect on the planet – trapping heat in the atmosphere.
The media event will occur from 9 a.m.-12 p.m. on Monday, Nov. 25 at NASA’s Langley Research Center in Hampton, Virginia. NASA Langley’s G-III aircraft and mobile laboratory, as well as GE Aerospace’s 747 Flying Test Bed (FTB) will be on site. NASA project researchers and GE Aerospace’s flight crew will be available to discuss the Contrail Optical Depth Experiment (CODEX), new test methods and technologies used, and the real-world impacts of understanding and managing contrails. Media interested in attending must contact Brittny McGraw at brittny.v.mcgraw@nasa.gov no later than 12 p.m. EST, Friday, Nov. 22.
Flights for CODEX are being conducted this week. NASA Langley’s G-III will follow GE Aerospace’s FTB in the sky and scan the aircraft wake with Light Detection and Ranging (LiDAR) technology. This will advance the use of LiDAR by NASA to generate three-dimensional imaging of contrails to better characterize how contrails form and how they behave over time.
For more information about NASA’s work in green aviation tech, visit:
https://www.nasa.gov/aeronautics/green-aero-tech
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David Meade
Langley Research Center, Hampton, Virginia
757-751-2034 davidlee.t.meade@nasa.gov
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