How NASA Uses Cryogenics
- October 15, 2020
- Cryogenic Processing
NASA is the premiere space exploration agency and as such, it relies on cutting-edge technology to carry out its functions. The agency is responsible for putting humans on the moon and it continues to push forward in our quest to learn more about the final frontier.
Space age technology isn’t limited to just science fiction movies. The agency has consistently led the way in advancing technology that has enabled humans to not only venture to space but even start thinking about a multi-planetary existence where nearby planets could one day be made habitable.
NASA’s history with cryogenics
The National Aeronautics and Space Administration has a long and storied history with cryogenics. It has utilized the process in many different projects, whether it be cryogenic materials being used as propellants in rockets to deep cryogenic treatments being applied to parts for rockets in order to increase their structural integrity.
NASA continues to devote a considerable amount of resources into the research and development activities that would allow it to further expand the use of cryogenics to achieve its objectives.
The Creek Road Cryogenic Complex is one such example. It’s NASA’s main cryogenic fluids technology test facility, located at the NASA Glenn Research Center. The facility can simulate a number of extreme environments that may include transients during launch, Low Earth Orbit, Lunar, Martian, and Titan atmosphere.
The Evolvable Cryogenics Project (eCryo)
The Evolvable Cryogenics Project is one of NASA’s biggest contributions to the evolution of cryogenics science. Its eCryo project is led and managed for the Space Technology Mission Directorate by the agency’s Glenn Research Center.
It’s supported by NASA’s Marshall Space Flight Center that also manages the Technology Demonstration Missions Program for the Space Technology Mission Directorate.
Through this project, NASA has been studying the use of high-energy propulsion solutions that will be critical to future human missions to space beyond Low-Earth orbit. Specifically, the project is concerned with the use of cryogenic propellants.
The cryogenic propellants are gases that are brought down to extremely low temperatures and then condensed to liquid form.
When these liquids, which include the likes of liquid oxygen, hydrogen, and methane, are kept at their ideal operating temperatures of – 297 degrees, – 423 degrees, and -259 degrees Fahrenheit respectively, they can be used for high-energy propulsion systems. The extremely low temperatures of these liquids do present a problem. It’s difficult to handle and store these cryogenic liquids.
There’s also the problem of these fluids evaporating or boiling off. This can happen when energy in the form of solar radiation or heat that’s conducted by the rocket structure raises the fuel temperature.
NASA has been working on eliminating this loss mechanism for the cryogenic fluids.
However, this boil-off can result in the loss of fuel mass when the rocket’s propellant tank reaches orbit. This happens to be a routine factor that NASA incorporates when calculating fuel loads but it’s working to eliminate this for future missions.
The challenge that still remains for the agency is to develop new solutions for in-space storage and transfer of cryogenic propellants. These solutions need to be energy-efficient, cost-efficient, and mass-efficient. The intended benefit would be to extend exploration missions throughout the solar system.
Four areas of focus
As the agency continues to work on advancing this science, it’s focusing on four key areas to ensure the maturation of cryogenic fluid management technologies that will fulfill the needs for NASA’s near-term missions.
Tools for Analysis
NASA wants to lean on sophisticated systems that can help predict boil-off, tank mixing, pressurization, and chill-down phenomena for both settled and unsettled cryogenic fluid systems. To that end, the organization invests resources into the development and validation of computer codes that will be capable of making these predictions.
Quantifying Multi-layer Insulation
Multi-layer insulation is a form of thermal insulation that’s made up from multiple layers of thin sheets. It’s often used on spacecraft and cryogenics as it’s one of the primary items of thermal design. This insulation is meant to reduce heat loss by thermal radiation.
As part of its eCryo project, NASA is testing and quantifying the thermal performance of thick multilayer insulation blankets at conditions and configurations that are representative of upper stage mission implementations of the SLS.
The SLS or Space Launch System is going to be the most powerful rocket that NASA has ever built. When it’s completed, the SLS will enable astronauts to undertake exploration journeys far into the solar system.
Vapor-based heat intercept
NASA is looking into innovative solutions for managing heat energy. It’s actively looking into the possible benefits of utilizing the vapor that’s vented by propellant tanks to intercept the heat that’s coming into the tank through structural elements of the space vehicles and rockets.
These tests are currently being conducted on subscale but based on this, the eCryo team will eventually be demonstrating vapor-based cooling at nearly full scale and in a configuration that is closely representative of a potential upper stage.
Radio frequency mass gauging
The agency has been looking into the use of radio frequency technology to estimate the liquid quantity in a propellant tank. This will be done by installing an antenna inside the tank and collecting the data through radio frequency mass gauge electronics.
As part of the eCryo project, NASA is quantifying the performance and accuracy of an RFMG system in microgravity. The technology will be implemented in a cryogenic tank that’s flown on the International Space Station as a demonstration.
NASA’s cryogenic fluid management methods
NASA considers cryogenic fluid management technology as being an integral part of the exploration systems that will be used for Earth-to-Orbit transportation, manned missions to the Moon and Mars, in addition to planetary exploration. The goal is to implement a Zero Boil Off system that ensures no propellant is lost.
Currently, the State of the Art for cryo-propellant storage is a loss rate of 3% per month in Low Earth Orbit through passive technology.
Even if the losses are brought down to 1% per month through advances in passive thermal control technology, it’s still unacceptable for a mission to mars that will take over two years.
The idea then is to use cryocoolers that will balance the entire parasitic and internally generated heat loads in the cryotank so that no propellant is lost. This delivers additional savings because there will no longer be a need for oversized tanks and a compulsion to carry extra propellant.
Cryocoolers are a main component of Zero Boil Off propellant storage systems. NASA is working on new developers that will significantly improve the performance of coolers meant for Zero Boil Off storage of liquid hydrogen.
The final development frontier is to achieve high efficiency and reliability for lower operating temperatures.
CTP Cryogenics’s work with NASA
Controller Thermal Processing Cryogenics has long worked with NASA on many of the agency’s important projects. We have cryogenically processed components for NASA’s space shuttle robotic arm in order to make it more robust.
NASA has independently conducted studies that have proved the release of residual stresses in welded aluminium after deep cryogenic treatment which has also been proven to create a phase change in cemented carbide.
Other studies have proven increases in fatigue life in steel springs as well as the load capacity of gears.
We are the industry leaders in deep cryogenic treatment, having decades of experience in this field with a long list of satisfied clients that include the likes of NASA, Remington Firearms, Air Liquide, US Repeating Arms, and more.
CTP Cryogenics offers a variety of services related to cryogenic processing and treatment.
Reach out today for a free quote for the thermal processing of metal parts, metallurgical advising, cryogenic processing with liquid helium, micro polishing, and sales of customized cryogenic treatment equipment.