Omega-3 Drinks Designed to Keep Astronauts Healthy on Deep Space Missions

At the moment two liquids meet inside a channel barely half a millimetre across, something quietly extraordinary happens. The surfactant molecules, more comfortable in water than oil, begin diffusing outward from the oil phase, and as they cross the boundary they drag tiny parcels of fish oil with them, assembling droplets roughly a hundred nanometres across without any mechanical force, any grinding, any heat. The process is called spontaneous emulsification, and it is, in a very literal sense, self-organisation. What comes out the other end of the T-mixer looks, to the naked eye, like slightly cloudy water. What it actually is, according to researchers at Adelaide University and the University of Nottingham, is a potential countermeasure against some of the most insidious threats facing astronauts on the way to Mars.

The scale of those threats tends to get lost in the excitement around deep space travel. Bone loss, muscle wasting, elevated cancer risk from cosmic radiation, chronic loss of appetite: these are the mundane, grinding realities of long-duration spaceflight, playing out across every hour that a human body spends in microgravity beyond Earth’s protective atmosphere.

A Diet With a Serious Gap

Current space food relies almost entirely on dehydrated and thermostabilised meals. They meet basic energy targets (on a good day) but astronauts have consistently reported reduced appetite in orbit, a phenomenon so well documented it has its own clinical name: space anorexia. Getting astronauts to eat enough is already difficult. Getting them to eat the right balance of nutrients, particularly those that happen to require fresh fish, is considerably harder. Omega-3 fatty acids cannot be synthesised by the human body and have to come from food; NASA currently asks astronauts on missions up to twelve months to eat canned tuna to meet their intake targets. For a Mars transit lasting three years, that approach stops making sense. Storage space alone becomes prohibitive.

The question Svenja Schmidt and her colleagues set out to answer was whether the gap could be filled from a glass instead. “Fortified beverage emulsions could potentially help there,” Schmidt says, “especially when providing nutrients at levels not met by normal nutrition.” The team chose omega-3 fatty acids as their target bioactive for two reasons that align neatly with the worst of what space does to the body. Omega-3s are associated with increased bone formation rates, potentially offsetting the skeletal resorption that microgravity accelerates, and with reduced cancer risk linked to oxidative damage from radiation. “We suggested omega-3 fatty acids to help protect against space radiation and increase the bone formation rate,” Schmidt says.

The technical challenge is not trivial. Omega-3 fatty acids come from fish oil, which is hydrophobic. Getting a stable, even distribution of hydrophobic material into a water-based drink requires emulsification, and conventional emulsification usually means energy input, specialised equipment, and heat that can damage the very molecules you are trying to deliver. None of those are appealing prospects for a machine running on the International Space Station or, eventually, on a vessel somewhere between Earth and Mars.

Self-Assembly in a Tiny Channel

Spontaneous emulsification sidesteps most of those problems. When the oil phase, containing the fish oil, carrier fats derived from coconut oil, aroma compounds, and a surfactant, meets the aqueous phase in the microfluidic T-mixer, the surfactant diffuses spontaneously across the interface and pulls oil droplets with it. No mechanical grinding. No temperature gradients threatening sensitive polyunsaturated fats. The continuous microfluidic process also produces smaller droplets than batch mixing, in the range of 80 to 120 nanometres depending on the recipe, and smaller droplets generally mean higher bioavailability. (At around 50 to 100 nm, absorption into cells is thought to reach something close to an optimum.)

The researchers worked through dozens of ingredient combinations to understand how each component affects droplet formation. Sucrose, perhaps predictably, makes the aqueous phase denser and more viscous, slowing down the surfactant diffusion and producing slightly larger droplets. Fish oil, rather counterintuitively, actually eased the emulsification process; the flexible molecular architecture of its polyunsaturated fatty acids, all those double bonds in the long carbon chains, seems to support diffusion in a way that the more rigid saturated fats do not. Aroma compounds (the team tested variants that smell of rose, orange, and fresh citrus) also helped keep droplets small by reducing the density and viscosity of the oil phase. Sugar fights the process; fish oil and fragrance work with it. That interplay shaped the final recipes.

Six formulations emerged: three flavour options paired with two sweetness levels, all containing fish oil at a concentration that delivers around 90 milligrams of combined omega-3 fatty acids per 330-millilitre serving. That is roughly a third of the recommended daily intake from a single drink. The taste, Schmidt notes, would be closest to a flat soda that has lost its carbonation, which is in fact the appropriate format for space; gravity-free environments prevent gas bubbles from rising in carbonated drinks, creating an unpleasant mouthfeel. The beverage library is designed to be customised on demand, with astronauts selecting their preferred flavour and sweetness from a software interface while a continuous production system mixes the relevant components in real time.

Still Some Distance from the Galley

Plenty remains unresolved. Taste testing has not yet been conducted in either gravity or microgravity. Shelf life under deep-space conditions (bombardment by radiation, launch g-forces, temperature fluctuations) is unknown. Fish oil is notorious for oxidising and developing off-flavours when exposed to air, a problem the team acknowledges will need careful stability engineering. The nanoemulsion droplets, being so small, are also subject to some safety scrutiny, though existing evidence for food-grade nanoemulsions suggests they are most likely digested normally in the upper gastrointestinal tract rather than absorbed intact.

The earthbound applications are probably closer in time than the astronaut ones. The microfluidic spontaneous emulsification approach could, in principle, be adapted for functional drinks produced at commercial scale, reducing the surfactant concentrations required and removing the need for energy-intensive homogenisation. The six beverage recipes are explicitly positioned as a starting library, to be extended with additional bioactives: vitamin D, notably absent from standard space diets, is an obvious candidate, and more flavour options.

For Volker Hessel, who leads the Adelaide research group, the broader framing seems to matter as much as the chemistry. “Being one small piece in the big puzzle of human space exploration and helping astronauts to stay healthy is a visionary privilege,” he says. The drinks are a long way from a Mars galley. What the work has demonstrated, though, is that spontaneous emulsification can produce stable, bioavailable, personalised fortified beverages in a system compact enough for a spacecraft, and that the molecular dynamics of fish oil and fragrance work in your favour when you get the chemistry right. Whether those nanometre-scale droplets will one day deliver omega-3s to an astronaut two hundred million kilometres from the nearest ocean may depend on how well the fizz of ambition survives the flat conditions of long-duration spaceflight.

Source: Schmidt et al., ACS Food Science & Technology (2026). DOI: 10.1021/acsfoodscitech.5c01291

Frequently Asked Questions

Why would astronauts need omega-3 drinks when they could just take supplements?

Omega-3 fatty acids need to reach cells in a bioavailable form, and nanoemulsion droplets in the range of 80 to 120 nanometres are absorbed more efficiently than many standard supplement formats. There is also the appetite problem: astronauts frequently lose their desire to eat in space, and a palatable, customisable drink may be easier to consume consistently than pills. NASA currently only supplements vitamin D; adding omega-3s to a beverage could address two space health risks, bone loss and radiation-related oxidative damage, in a single serving.

How is a drink that contains fish oil made to taste acceptable?

The oil is dispersed into droplets so small they scatter light but cannot be tasted as individual particles; the resulting drink has a consistency similar to a flat soda. The researchers added aroma compounds (rose-like geraniol, orange R-limonene, or fresh-citrus citronellol) to mask the fish oil’s characteristic flavour and provide variety. Interestingly, those same aromatic compounds also improved the emulsification process by reducing oil phase viscosity, so the flavouring is doing double duty. Formal taste testing in both gravity and microgravity has not yet been carried out.

Could the same technology be used to make fortified drinks here on Earth?

The spontaneous emulsification process used in this research does not require the energy-intensive homogenisers used in conventional beverage production, which could reduce manufacturing costs and avoid the heat damage that degrades sensitive bioactives. The researchers suggest the approach could be adapted for commercial functional drinks, with a wider range of vitamins and bioactives added beyond omega-3s. Whether the process would scale up economically to mass production remains an open question, but the basic chemistry is the same regardless of gravity.

What stops astronauts from just eating enough canned fish to get their omega-3s?

Storage capacity is the fundamental constraint. A Mars mission lasting up to three years would require volumes of food that current spacecraft simply cannot carry, which is why researchers are exploring both in-space food production and concentrated nutrient delivery systems. Astronauts on shorter missions are already asked to eat canned tuna to meet omega-3 targets, but dietary monotony is itself a known problem, reducing appetite further. A customisable drink offering three flavour profiles and two sweetness levels represents a meaningful improvement in variety for a diet that otherwise changes very little.