One of the key missions of human space travel is the search for extraterrestrial life, and we're doing our best to find the answers.
To satisfy this curiosity, it's why the spaceships we send out into the universe have to be sterile.
Why?
Because we have a responsibility to protect the Earth.
The planet must be protected from other planetary life.
Try to imagine the consequences if flesh-eating bacteria from Jupiter traveled to Earth on a returning spacecraft!
Well, humans might become their food.
That's why scientists do their best to make sure spaceships are sterile.
The main question is ...... how do they do that?
In the early days of space travel, spacecraft components were heated at 110-200 C in humidity-controlled dry ovens.
They were also kept in hot air ovens for several days to ensure maximum sterilization.
In 1975, this method was used to sterilize the Viking landers sent to Mars.
However, heat sterilization was not always an option.
First, spacecraft assembly is challenging.
Thermal sterilization of complex electronic components, such as sensitive temperature sensors, can damage the parts.
The alternative is to use ultraviolet (UV) or gamma radiation.
Exposure of spacecraft components and their equipment to these high-energy rays damages the DNA of microorganisms and kills them.
As an added measure, assembled parts are also wiped down with 70% alcohol or hydrogen peroxide to kill any remaining survivors.
However, these chemicals should not be used anywhere as they can damage the epoxy or silver coatings on the ship's components or equipment.
So heat, radiation, and chemicals are all used to keep spaceships and equipment sterile, but that's not the end of the precautions.
Spaceships are also assembled in clean rooms that must meet federal standards (FS 209).
Even with all this foresight, these methods are not foolproof.
Some bacteria can adapt and are heat resistant, such as Bacillus.
Bacillus spores are also very tough and can withstand high temperatures, pressures, and radiation exposure. They can survive high temperatures for several minutes.
The use of chemicals is not 100% effective.
In addition, due to our new and physically sensitive modern technological instruments, it is not possible to completely sterilize using the above methods.
What is a safer alternative? We invite plasma to take the stage!
You probably know that plasma is the fourth state of matter.
Plasma is essentially charged or ionized gas.
Examples of natural plasma include lightning in a storm and the Northern Lights.
Plasma is made by exciting gas molecules until their electrons fall out of the orbits of the atomic nuclei.
As these electrons release their energy, bright characteristic plasma colors can be seen.
This sterilization technology was originally invented by Johnson & Johnson to sterilize heat- and moisture-sensitive medical devices.
Electrode chambers with electrodes containing reactive chemicals, such as nitric acid or hydrogen peroxide, are used to create the plasma.
An electric current is passed through the chemical and vaporizes it.
The resulting gas molecules, such as O 3 molecules, are ionized.
The charged gas molecules bombard the bacteria and disrupt their biological processes and damage their DNA, essentially killing them.
Plasma is superior to other sterilization methods in several ways. These gases can be charged using an electric current at temperatures as low as 40 C.
This makes it safer to use on heat-sensitive materials and devices.
It also prevents direct chemical contact with the device, making it safer to use on different spacecraft materials.
Plasma sterilization also has a higher sterilization efficiency than heat or radiation sterilization. It can even kill heat-resistant bacterial spores.
By this point, you're probably wondering why we bother killing bacteria on spaceships in the first place ......
After all, some bacteria can't be that bad, right?
At the beginning of this article, we mentioned the word planetary protection, remember?
Protecting other planets and solar system bodies from life on Earth is an internationally recognized practice.
It works both ways, because we also want to protect Earth from potential alien life forms from outer space.
This is where planetary protection comes in handy.
Let's assume another rover lands on Mars looking for alien life.
However, this ship is not properly sanitized, and it carries a bacteria all the way from Earth to Mars.
Once the rover landed on Mars and traveled around the red planet, the Earth bacteria from the rover landed on Mars.
At that point, it can mutate and adapt to the Martian environment.
Now, the rover is starting to take soil samples and eventually pick up this modified bacteria for study.
Scientists on Earth will think they've found life on Mars, but the ugly truth is that this life actually came from Earth.
Mistakes like this could undermine the search for foreign life.
Space travel is not cheap, so such mistakes would waste billions of dollars and undermine the integrity of space exploration.
Bacteria mutate rapidly in space, so in our exaggerated hypothetical scenario, it is theoretically possible that a space mission could last long enough to "discover" and mistake Earth bacteria for Martian varieties.
Furthermore, not only could bacteria mutate and survive in space, they could also transform into something dangerous.
One study found that E. coli grown in space have different physical properties due to changes in microgravity.
These physical changes make it difficult for antibiotic drug molecules to penetrate their cell membranes, meaning that E. coli grown in space are antibiotic resistant.
Other dangerous changes that bacteria may face in space can only be speculated upon, but none of us want to find out the hard way.
In addition, spacecraft carrying bacterial infections pose a threat to the health of astronauts.
Astronauts' immune systems are already weakened in space.
If an astronaut contracted a terrible disease or infection, it would be very difficult to treat without the right hospital or adequate medical resources, which remains a luxury on Earth.
Strict quality control measures are already in place when spacecraft are built.
Planetary requirements may seem trivial, but they should not be taken lightly.
The impact of extraterrestrial life on Earth's ecosystem and balance is immeasurable.
This is why, if any object from space crashes into Earth, the surrounding crash site is cordoned off and decontaminated.
Plasma disinfection makes it easier to uniformly sanitize a spacecraft without damaging sensitive equipment or delicate materials on board.
It is necessary to ensure that spaceships remain sterile because if large quantities were to enter the ship, they could be highly detrimental to the integrity and safety of the mission.
Astronauts must also maintain good hygiene practices, as their skin or intestinal bacteria can also enter the air circulation of the spacecraft and spread everywhere.
When it comes to space travel, cleanliness is king!
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