Yes, rust can grow in certain parts of space, but not in others. The possibility of rust forming depends heavily on the specific environment, particularly the presence or absence of oxygen.
Rust, which is the oxidation of iron, requires an oxidizer (typically oxygen) to form. Space is not a uniform vacuum; conditions vary greatly depending on location.
Rust in Low Orbit
In low Earth orbit, where satellites and the International Space Station typically operate, there is a tenuous atmosphere. At these altitudes, oxygen exists but is often in a more reactive form: single atoms rather than the O₂ molecules we breathe.
As noted in studies:
- "At that altitude [low orbit], oxygen exists as single atoms, rather than O2 molecules, and it is more reactive."
- This reactive atomic oxygen can interact with spacecraft materials. While some materials like aluminium and stainless steel form a protective oxide layer and resist corrosion, others are vulnerable.
- "Silver and iron corrode quickly in low orbit."
Therefore, if exposed, iron-based materials can and do corrode (rust) in the low-orbit environment due to the presence of reactive atomic oxygen.
Rust in Deep Space
Moving beyond low orbit into deep space, the conditions change dramatically. Deep space is characterized by an extreme vacuum.
The reference states clearly:
- "In deep space, however, the lack of oxygen means that corrosion does not occur."
Without the necessary oxygen atoms to react with iron, the process of oxidation, which leads to rust, simply cannot happen.
Implications for Spacecraft Design
Understanding where and why corrosion occurs in space is crucial for engineering spacecraft. Materials must be carefully selected based on their destination and expected environment.
- Materials like aluminium, which forms a protective oxide layer, are often used for structural components.
- Stainless steel, another material mentioned as resistant to corrosion in low orbit, is also common.
- Materials like iron and silver, which corrode quickly in low orbit, would need to be shielded or avoided for external components in that environment.
In summary, rust requires oxygen. While reactive oxygen is present in low Earth orbit, enabling iron to corrode, deep space lacks sufficient oxygen, preventing rust from forming.
