The Zero G Kitchen Oven is the first-ever oven in space! Before the Zero G Oven, no food item had ever been cooked from the raw in space. The oven is a cylindrical-shaped insulated container designed to hold and bake sealed food samples in the microgravity environment of the International Space Station (ISS).
The oven allows food samples to be placed in a tray where they will be held steady inside the oven while baking occurs. A cooling rack is also integrated into the outside of the oven. The insulation and venting mechanisms allow the oven to operate safely in the controlled environment of the ISS.
First, let’s talk about how a typical convection oven works here on Earth!
On Earth, air in the oven is heated, either by an electric heating element or gas burner mounted in the bottom of the oven, and as the air heats up it expands and becomes less dense. The lower density then causes a pocket of hot air to “float” in the cooler air around it and the pocket of air rises, just like a bubble would in water. As the hot air floats away from the heating element, cooler air moves in to replace it, then gets heated, and the cycle continues.
This continuous cycle of hot air rising and cool air moving in to replace it sets up a constant flow of air called a convection current in the oven. This causes the air in the oven to circulate and uniformly distribute the hot air throughout the oven causing a smooth temperature profile and allow for even cooking.
So, things have to be different in space, right?!
Correct! Microgravity brings an entirely new element to kitchen appliances.
In space, we operate in a microgravity environment – so for the Zero-G Oven on the International Space Station, there is no “up” direction for the hot air to float towards. So, if a normal convection oven went to space, the air would not flow away from the hot element, and convection currents would not be set up, making it inoperable in space. On the Space Station we can only depend on heat being conducted through the air.
Nanoracks designed the Zero G Oven with this in mind, and placed heating elements around the entire oven interior to ensure that heat is distributed evenly in the cooking chamber. Heat concentrates and develops a pocket of hot air at the center of the Zero G Oven cooking chamber. This allows the oven to reach cooking temperatures while using far less power than a conventional oven does on Earth.
All of Nanoracks’ designs had to meet strict NASA safety standards to maintain the safety of the astronaut crew and critical infrastructure on board the Space Station.