Introduction and Effects of Microgravity
As India demonstrated the first successful launch of Gaganyan testing module, we took one step closer to our first manned space mission. This test was aimed at demonstrating whether the crew can safely escape the module in case it malfunctions when the actual Gaganyan mission is launched in 2025.
Read: December Issue of Food Infotech Magazine.
For the uninitiated, Gaganyan mission is to take a 3-4-member crew on a 3-day space ordeal in near earth orbit (400 Kms). Manned space mission is extremely difficult not only from the operations perspective, but also from the crew members physical as well as mental well-being perspective. The gravitational force experienced on Earth and in space differs significantly, due to the presence or absence of massive celestial bodies.
On the surface of the Earth, the gravitational force is relatively constant and is approximately 9.8 m per second squared (9.8 m/s2). It keeps objects and people grounded creating a downward force. In space, particularly in low Earth orbit such as on the International Space Station (ISS), the force of gravity is significantly reduced compared to Earth’s surface. This creates a condition known as microgravity. Astronauts in orbit experience a state of continuous freefall around the Earth, giving them the sensation of weightlessness. When travelling to more distant destinations, such as the Moon or other planets, the gravitational force decreases even further.
This effect of microgravity or the condition of experiencing very weak gravitational forces has several effects on astronauts’ health, due to the significant changes it introduces to the human body’s adaptation processes.
Microgravity influences biochemical changes in the body, because it disrupts the normal physiological conditions that organisms have evolved under on Earth. The absence of gravity’s mechanical stress, alterations in fluid distribution, disruption of cellular signalling, sensory changes and environmental factors in microgravity all contribute to the biochemical changes observed in the body.
The body’s adaptation mechanisms to microgravity also trigger complex biochemical responses. Few biochemical changes include:
– Bone and Muscle Loss;
– Change in the mineral composition of the body;
– Hormonal imbalances;
– Abnormal digestion and absorption;
– Abnormal Iron metabolism;
– Impacts of oxidative stress;
– Ophthalmological issues;
– Reduced immune response.
SPACE GOURMET
Space missions can have a significant impact on astronauts’ health, including changes in bone density, muscle loss, hormonal imbalances and immune system functioning. Developing advanced space food ensures that astronauts receive adequate nutrition to support their physical health and well-being during space travel. Proper nutrition is essential for optimal cognitive function, concentration and performance.
The different forms in which food is provided for Near Earth Orbit missions include the following:
1. Thermo Stabilized:
This process, also known as the retort process, heats food to a temperature that renders it free of pathogens, spoilage microorganisms and enzyme activity. Products for Astronaut consumption include pouched soups, sides, desserts, puddings and entrees.
2. Irradiated:
Irradiation is not typically used to process foods to commercial sterility. However, NASA has received special dispensation from the Food and Drug Administration (FDA) to prepare 9 irradiated meat items to commercial sterility.
3. Rehydratable:
Both commercial and internally processed freeze-dried foods are included in the NASA food provisions and then rehydrated during the mission using the potable water supply. Rehydratable foods are typically side dishes, such as spicy green beans and cornbread dressing or cereals. Ambient and hot water are available to the crew for rehydration of these items.
4. Natural Form:
Natural Form foods are commercially available, shelf stable foods. The moisture of the foods may range from low moisture (such as almonds and peanuts) to intermediate moisture (such as brownies and dried fruit). However, all have reduced water activity thus inhibiting microbial growth. These foods help to round out the menu by providing very familiar menu options, additional menu variety and foods requiring no preparation time.
5. Extended Shelf-life Bread Products or Items:
Extended Shelf-life bread products or items, such as scones, waffles, tortillas and dinner rolls can be formulated and packaged to give them a shelf life of up to 18 months. Like the natural form foods, breads add to menu variety and address crewmembers’ desire for familiarity.
6. Fresh Food:
Foods such as fresh fruits and vegetables that have a short shelf life are provided on a limited basis, more for psychological support than as a means to meet dietary requirements.
7. Beverages:
The beverages currently used on the International Space Station (ISS) and the Space Shuttle are either freeze-dried beverage mixes (such as coffee or tea) or flavoured drinks (such as lemonade or orange drink). The drink mixes are weighed and then vacuum sealed inside a beverage pouch. In the case of coffee or tea, sugar or powdered cream can be added to the pouch before sealing. Empty beverage pouches are also provided for drinking water.
Space Gastronomy 2.0: Adapting Nutrition for Extended Spaceflight
The change in mission duration for trips to asteroids, Mars and other extended missions beyond low Earth orbit will necessitate an evolution of the food system. The Mars missions, in particular will require development of technologies to enable the crew to be self-sufficient and less dependent on resupply missions. One proposed mission to Mars designates use of the pre-packaged foods, similar to those used on the ISS for transit but may also include positioning food on Mars before the crew arrives.
Under this scenario, prepositioned food may be 3-5 years old at the time of consumption. Achieving a 5 year shelf life to make this mission scenario feasible is an ambitious goal, given that the current pre-packaged foods have a stated shelf life of 18 months. The determining factors for shelf life, safety, nutrition and sensory acceptability must be optimized to maximize the shelf life within the mission scenario. These missions will also require that more attention be paid to utilization of resources including mass, volume, power, crew time and water.
The challenges are significant but not insurmountable, especially if the key needs are dissected individually. The following 5 items encompass the major technological and development needs for the space food system to successfully supply long exploration missions:
1. Nutrient-Dense, Shelf Stable Foods That Meet Overall Sensory Acceptability Metrics
While energy density is a key consideration in the definition of healthy diets for industrialized nations, a crucial factor for the space program is the mass of the food required to deliver the energy and the micronutrients. Due to paucity of storage, the endeavour is to deliver nutrient dense food with reduced footprint to meet the calorific requirement of the Astronauts. For example, in the case of Gemini Food System, bite-size cubes of meat, fruit, dessert and bread products were engineered to deliver 21.3 J/g and the complete food system offered 12100 J or about 2890 cal, in 0.73 kg of packaged food. However, the in-flight acceptability of cubes quickly waned and many cubes were returned uneaten.
Current ISS and Shuttle crewmembers receive about 1.8 kg of food containing all 16 nutrients (protein, calcium, iron, vitamin A, vitamin C, thiamine, riboflavin, vitamin B12, folate, vitamin D, vitamin E, magnesium, potassium, zinc, fibre and pantothenic acid) plus packaging per person per day. A higher percentage of this food is thermostabilized because the thermostabilized food is still generally preferred in taste tests to freeze-dried items by crew members.
2. Shelf Stable Menu Items with at least a 5 Year Shelf Life
Commercial shelf stable food products are generally accepted as having sufficient shelf life, if the product is still consumer-accepted 1 year after manufacturing. NASA assigns an 18 to 24 month shelf life to most space food provisions, but even this span is inadequate for future deep space missions. Food quality is predicted to have a pronounced role in crew psychological well-being, owing to the isolation and confined space associated with extended missions (Evert and others 1992). Hence, ensuring the quality of the food up to the point of consumption is paramount.
The 2 technologies with the most promise are High-Pressure Processing (HPP) and Microwave Sterilization. HPP is a method of food processing in which food is subjected to elevated pressures (up to 600 MPa or approximately 6000 atmospheres), with or without the addition of heat to achieve microbial inactivation or to alter the food attributes to achieve qualities desired by consumers. Pressure inactivates most vegetative bacteria at pressures above 415 MPa. HPP retains food quality, maintains natural freshness and extends microbiological shelf life. (Ramaswamy and others 2010)
Microwave sterilization is a high-temperature, short time process in which the packaged food is cooked at 129°C for 10 minutes (Natick 2004). The current thermostabilized NASA food products are cooked to about 121°C, but for a much longer time.
3. Partial Gravity Cooking Processes with Minimization of Microbial Risk
Although, the risk of foodborne illness from pre-packaged food is successfully mitigated with the current safety procedures (HACCP, GMP), the foray into other food sources changes the risk landscape significantly.
Specifically, once NASA builds extraterrestrial habitats, food may not be limited to only pre-packaged food. Crewmembers may be required to harvest hydroponically grown produce, store and repackage ingredients in the foreign environment and cook with equipment engineered for a partial gravity surface. The potential contamination points of the food supply will increase, unless an equally stringent HACCP plan is applied to the new system.
During ingredient processing and subsequent preparation of meals during long-duration exploratory missions, it will be necessary to reach a certain temperature-time combination to ensure safety and certain functionality. Past proposals assumed that the lunar habitat will maintain an atmospheric pressure of 55 kPa. Heat and mass transfer are affected by partial gravity and reduced atmospheric pressure. At that pressure, the boiling temperature for water is 82.8°C. Understanding the physical changes in the environment and the impact to food preparation and processing is critical to estimate the microbial load throughout the cooking, quantify the risk of foodborne illness and reduce the risk to acceptable levels. A viable microbial risk could delay a long lunar mission, even if all other elements of the mission were ready. Mission loss or major impact to post mission crew health would likely occur if this risk is not quantified and reduced.
4. Sustained Vitamin Delivery in Shelf Stable Foods
Without adequate nutrition, human performance and sustainment are endangered. Adequate nutrition has 2 components—required nutrients and supplied energy in the form of calories. Distinct health issues stem from inadequate calories and from inadequate micronutrient intake; for example, vitamin C deficiency leads to scurvy and a deficiency in niacin may result in pellagra. It is important that the crew members are provided with the required levels of nutrition throughout their missions to prevent disease. Fig. 3 summarizes the nutritional requirements as stated in the NASA Constellation Program (C×P) document 70024, “Human-Systems Integration Requirements,” section 3.5.1.3.1.
Several studies indicate considerable loss of vitamins like Folic acid, Thiamine, Vitamin A, Vitamin C and Vitamin K in space ready food. In one of the study, food was prepared as per space readiness protocol and then stored at 22°C for 5 years. The conclusion of the study was that thermal stabilization of foods induced degradation of Vitamin A, C, Thiamine and Folic acid. Therefore, nutritional loss at 3 and 5 year is predicted to be significant and would likely result in inadequate nutrition in the food system.
Therefore, the use of encapsulated vitamin fortification or growing fresh fruits and vegetables at an extraterrestrial base camp can provide the crew with a variety of fresh foods and associated nutrients. These fresh foods should provide at least some of the vitamins that may be lost over time in the processed foods, enhancing the nutritional intake of the crew and their subsequent health and thereby reducing the risk of inadequate diet.
5. Packaging Material that meets High-Barrier, Low-Mass and Process-Compatibility Constraints
Food packaging is a major contributor to mass, volume and waste allocations for NASA missions. Yet, packaging is integral to maintaining the safety, nutritional adequacy and acceptability of food, as it protects the food from foreign material, microorganisms, oxygen, light, moisture and other modes of degradation. The higher the barrier provided by the packaging, the more the packaging can protect the food from oxygen and water ingress from the outside environment. Oxygen ingress can result in oxidation of the food and loss of quality or nutrition. Water ingress can result in quality changes such as difficulty in rehydrating the freeze-dried foods and in increased microbial activity.
The packaging materials used for the thermostabilized, irradiated and beverage items contain a foil layer to maintain product quality beyond the required 18-m shelf life. Although the foil layer provides the desired protection, the material is not compatible with some emerging technologies that produce high-quality, commercially sterile foods. This incompatibility will require NASA to either continue using the foil packaging or forego the new technologies or to acquire new packaging compatible with those technologies. In addition, foil packaging complicates plans to incinerate trash in the future. Incineration is postulated as a possible solution to trash accumulation at an extraterrestrial base. However, the foil layer within the food package will not incinerate completely and will leave some ash from the foil.
Finally, as previously mentioned, metallized films generally do not provide the transparency necessary for the human inspection of products after packaging.
Cosmic Cuisine: Innovations in Space Food Technology
Embarking on the uncharted odyssey of space exploration demands not only technological prowess, but also a profound understanding of the fundamental human need for sustenance. In this cosmic frontier, the evolution of space food has transcended traditional paradigms propelled by a constellation of groundbreaking technological interventions.
1. As NASA pioneers the frontier of space farming, experiments aboard the International Space Station (ISS) have sprouted the cultivation of crops like lettuce, ushering in a new era of fresh and locally grown provisions for astronauts.
2. The integration of 3D printing technology offers a tantalizing prospect of customized and on-demand meals, not only enhancing variety but also curbing food waste in the extra-terrestrial environment.
3. Venturing further, closed-loop systems now stand on the frontier of innovation, promising not just waste recycling but a sustainable approach to long-duration missions by repurposing waste into usable resources, including food production.
4. Portable food analyzers orbit the realm of real-time nutrition monitoring, ensuring that astronauts receive the essential nutrients vital for their well-being.
5. Bioreactors join the cosmic kitchen, cultivating microorganisms like yeast and bacteria to synthesize crucial food components such as proteins and nutrients.
6. The extra-terrestrial agricultural landscape expands with the exploration of hydroponics and aeroponics, soil-less farming techniques that could revolutionize plant cultivation in space.
7. Beyond conventional farming, researchers are delving into bio printing technology, contemplating the creation of edible foods using cell-based materials, heralding the prospect of customized, nutrient-rich diets for astronauts.
8. Algae-based foods, rich in essential nutrients and grown efficiently in closed-loop systems emerge as a sustainable contender for future space missions.
9. The emergence of cultured meat technology presents a livestock-free alternative, casting a new light on space food production.
10. Smart food systems, equipped with sensors and IoT technology are poised to revolutionize meal monitoring, ensuring both the safety and nutritional integrity of space fare.
11. Genetic engineering casts its gaze towards crops genetically tailored for space conditions, resilient to radiation and thriving in limited resources.
12. Advanced space greenhouses provide a controlled haven for plant growth, cultivating fresh produce amidst the cosmic void.
13. Insects, efficient converters of organic matter into high-protein biomass become a compelling candidate for space gastronomy.
14. Artificial Intelligence and Robotics make their mark, automating the entire food production cycle from planting and harvesting to meal preparation aboard spacecraft.
15. Waste recycling systems underscore sustainability, minimizing reliance on resupply missions from Earth.
Yet, as we unravel the technological tapestry of space food, we must not overlook the human dimension. Ongoing research delves into the psychological nuances of space dining, acknowledging the importance of variety, flavours and communal dining for the mental well-being of astronauts embarking on extended missions. Together, these technological marvels and psychological considerations form the warp and weft of a culinary odyssey into the cosmos, where innovation not only sustains the body but nourishes the spirit of exploration.
Reference:
1. https://www.sciencedirect.com/science/article/pii/S2590157523003188
About the Author:
Bharat Sawnani
Founder, Elevantus Food Consultants
Email ID: sawnani@gmail.com
