RSS

Category Archives: Space Program

Q and A: What Happens When a Person Is Exposed to the Vacuum of Space?

Astronaut

Q: What sort of damage does the human body suffer in the vacuum of space?  How long can one survive and what will happen to the person who does survive?  My scenario involves an astronaut whose faceplate blows out, but not before he depressurizes his suit sufficiently to prevent immediate death.

A: First of all the victim would not explode as was the case in the movies such as Total Recall. But some very bad things do happen internally and they happen very quickly. Whether he depressurizes somewhat beforehand or not, his survival once he reached zero pressure (vacuum) would likely be measured in seconds.

Space decompression sickness is similar to that of a scuba diver that rises too rapidly after a prolonged exposure to the pressures of the deep. In this case the diver is going from excess pressure to normal pressure. In space the victim goes from normal pressure to zero pressure. Same thing physiologically.

In diving, the problem is that the excess pressure causes excess nitrogen (N) to dissolve in the blood. This N will come back out of the blood as the pressure is reduced. This should happen slowly to prevent decompression sickness or the bends. But, if the diver rises rapidly, the pressure drops rapidly, and the N comes out of the blood quickly, forming N bubbles in the blood stream. This is similar to popping the top on a soft drink. Here the release of the pressure allows the carbon dioxide (CO2), which was placed into the liquid under pressure, to come out of the liquid and form bubbles. We call this carbonization. A good thing for your soft drink, but not so good for your brain and heart and muscles.

In space decompression basically the same thing happens. Apparently the culprit is water and not N in this situation, however. With the sudden release of pressure, the water in the blood “boils,” becoming a gas, and bubbles form in the system. I should point out that in chemical and physical terms boiling simply means the changing of a liquid to a gas. This can be accomplished by adding heat (boiling water on a stove) or by lowering the ambient pressure (popping open a soft drink). In the case of space decompression it isn’t that the blood gets hot, but rather that the pressure that keeps the water in its liquid state is removed and the water changes to its gaseous state, or boils. Doesn’t sound very pleasant does it?

Though studies on the effects of exposure to a vacuum have been done on chimpanzees, there are no real data on what happens to humans exposed to zero pressure except for a couple of incidents where an astronaut or a pilot was accidentally exposed. Of course, rapid decompression has caused deaths in both high-altitude flights and in June, 1971 when the Russian spacecraft Soyuz 11 suddenly lost pressure, killing the 3 cosmonauts on board, but survivors are few and far between.

On August 16, 1960, parachutist Joe Kittinger ascended to an altitude of 102,800 feet (19.5 miles) in an open gondola in order to set a world record for high-altitude parachute jumping. He lost pressurization in his right glove but proceeded with his ascent and jump. He experienced pain and loss of function in his hand at high altitude but all returned to normal once he descended via chute to lower altitudes.

In 1965 at NASA’s Manned Spacecraft Center near Houston, TX, a trainee suffered a sudden leak in his spacesuit while in a vacuum chamber. He lost consciousness in 14 seconds, but revived after a few seconds as the chamber was immediately re-pressurized. He suffered no ill effects—due to his very brief exposure—but stated that he could feel water boiling on his tongue. This was actually the above mentioned boiling scenario in which water (in this case saliva) becomes a gas on exposure to zero pressure.

A case of partial, prolonged exposure occurred during an EVA (space walk) in April 1991 on the US space shuttle mission STS-37. One astronaut suffered a 1/8 inch puncture in one glove between the thumb and forefinger. He was unaware of it until later when he noticed a painful red mark on his skin in the exposed area. It appeared that the area bled some but that his blood had clotted and sealed the injury.

So, what happens to a human exposed to zero pressure? Since there is no oxygen in such an environment, loss of consciousness occurs in a matter of seconds. Also, if the victim held his breath (don’t do this during scuba diving when coming up from depths either), the air in his lungs would rapidly expand and his lungs could be damaged, bleed, or rupture. Better to open his mouth and exhale the rapidly expanding gas from his lungs.

Water in his blood stream would immediately begin to “boil,” filling the blood stream with water vapor (the gas form of water) and stopping his heart. Bubbles might appear in the blood stream and cause damage to the body’s organs, particularly the brain. As a result, the brain and nerves cease to function. As more and more gas formed within the body, the entire body would swell but it would not explode.

Exposure to heat or cold or radiation might also occur but it will do little harm since the victim would already be dead.

But what if the exposure were brief and the person rescued? Treatment would be to immediately return him to a pressurized environment and give him 100% oxygen. He may survive unharmed or may have brain and nerve damage which could be permanent.

For your scenario, whether he partially decompressed or not, he would be in trouble very quickly. When your victim’s faceplate ruptured he would hopefully begin to exhale air to prevent the expanding gases in his lungs from rupturing them. As air, and thus oxygen, flowed from his lungs and into space, the oxygen content of his blood would rapidly drop and he would lose consciousness in 10 to 20 seconds. He would then die in short order. If he were quickly rescued, he would be returned to the spacecraft, which would be pressurized, and would be given 100% oxygen via a face mask. He could survive intact or with brain damage. It’s your call. Either way works.

 

Do Astronauts Hallucinate?

It has long been known that isolation can lead to all sorts of psychological problems, including delusions and hallucinations. Prisoners in isolation, who have limited interaction with others, can suffer just such effects.

In medicine, we see it frequently. Someone has surgery, and then for whatever reason (complex surgical problems, complications, co-morbidities, etc.) must linger in the ICU for a few days. This is a form of isolation as they are limited in their activity and in who they see and talk with on a regular basis. Sort of like prison isolation. Not to mention they might be receiving medications for pain, sleep, or agitation, each of which can alter mental function. After as little as a couple of days, the person can become confused and disoriented and suffer delusions, such as everyone is trying to kill them, or they are being held prisoner and undergoing some alien experimentation, as well as hallucinations where they see, feel, and hear things that don’t exist. Seen it hundreds of times. It’s that common.

icu

It even has a name: ICU Psychosis.

Astronauts are in a similar situation. They spend months in an enclosed, monotonous environment, interacting with the same people, day after day. It’s like prison, or an ICU. Do they also develop delusions and hallucinations? It seems that the do. In fact, I would be surprised if they didn’t.

astronaut-moon

So, during a trip to Mars, where isolation is very real, could such psychiatric problems jeopardize the mission? You bet. NASA takes this seriously and has begun studies into such long-term deprivations.

HI-SEAS

MedNet: ICU Psychosis: http://www.medicinenet.com/icu_psychosis/article.htm

NIH: Intensive Care Unit Psychosis: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2154033/

Astronauts and Hallucinations: http://www.theguardian.com/science/2014/oct/05/hallucinations-isolation-astronauts-mental-health-space-missions

NASA Trains Astronauts to Bins, Tranquilize Unstable Crewmates: http://www.foxnews.com/story/2007/02/25/nasa-trains-astronauts-to-bind-tranquilize-unstable-crewmates/

NASA Has Guidelines for Dealing With Psychosis in Space: http://www.utsandiego.com/uniontrib/20070224/news_lz1n24read.html

Mars One Astronaut Training Program: http://www.mars-one.com/faq/selection-and-preparation-of-the-astronauts/how-are-the-astronauts-prepared

NASA’s HI-SEAS Training Program: http://www.sci-news.com/space/science-nasas-hi-seas-team-hawaii-mars-mission-02220.html

 

Drowning In Space: When Your Space Suit Is Your Enemy

Gemini 4 Spacewalk

Gemini 4 Spacewalk

 

You would think that the last thing that an astronaut would fear while performing a spacewalk would be drowning. How on earth does that happen? Oh, wait a minute, he wouldn’t be on Earth. I guess out there in the wild blue yonder all the rules change. Ask Luca Parmitano, an Italian astronaut who worked on board the International Space Station (ISS). It seems that over a liter of water accumulated inside his helmet obstructing his ears and his eyes and raising the possibility that he could drown in space.

He isn’t the only one to suffer spacesuit problems during spacewalks, Extravehicular Activities or EVAs in NASA-speak. Here is an interesting article from The New Scientist on five such situations.

 

 
3 Comments

Posted by on September 3, 2013 in Asphyxia, Medical Issues, Space Program

 

Surgery in Zero Gravity

How do you do surgery in zero gravity?

Very carefully. And it helps to have NASA’s latest toy.

You’ve probably seen videos of astronauts playing with water in space. No dripping or dropping here. Due to their inherent surface tension and the lack of gravity applying any external force, liquids tend to form into spheres and float around. Fun stuff.

 

But what about blood? Of gall bladder fluid? Or, yuck, pus from an infected wound? These are not materials you want floating around in your space capsule, or your face.

The Aqueous Immersion Surgical System (AISS) just might solve this problem. It is a saline-filled transparent box with airtight ports through which orthoscopic surgical tools can be passed.

 

 

Very clever and very cool.

 
 

Space Travel and Brain Injury

We’ve been to the moon, astronauts have spent months floating around the space station, and the dream of many is to eventually visit Mars. But, space isn’t all that friendly to humans.

 

The Original 7 Mercury Astronauts

 

Besides the obvious dangers associated with take off and re-entry, and living in an enclosed environment miles above the Earth where immediate rescue is problematic, there are several important medical issues related to prolonged microgravity exposure.

 

Apollo 11’s Buzz Aldrin on the Lunar Surface

 

For years we’ve known about the muscle wasting and bone mineral loss that follows the absence of weight bearing in microgravity. Now a new problem has been uncovered: Idiopathic Intracranial Hypertension.

That’s a big word meaning an elevation of the pressure inside the skull. This seems to be due to cerebral edema, an excess accumulation of fluid within the brain that leads to brain swelling. And since the skull, unlike a balloon, is rigid and cannot expand with this increased pressure, the brain suffers.

In a NASA study of 27 astronauts who had spent an average of 108 days in space, MRI brain scans revealed that one third suffered some degree of swelling, typically involving the optic (vision) nerves. In some astronauts, there was also some flattening of the back of the eyeball, which affected focusing, and problems with the pituitary gland, the so-called master gland that regulates many of the body’s hormones.
This will require further study, but on its surface it appears to complicate long-term space travel. Mars just got a little further away.

 

 
1 Comment

Posted by on July 17, 2012 in Medical Issues, Space Program

 

Q and A: Could the Sensitivity of Modern DNA Testing Prove Confusing in a Contaminated Crime Scene?

Q: I attended your forensics panel at SINC OC and remember you saying that DNA can be extracted from a single cell found at the scene. Is that correct? I have a meticulous serial killer that I want to leave only DNA clues but (for me at least) that begs two questions: How far is the one-cell method of DNA ID developed now and wouldn’t the DNA results become muddied since many persons would have been in the same area? In other words, how would friends/family/acquaintances be ruled out or in as suspects when they most likely would have physical contact with the victim?

P.I. Barrington, Riverside, CA

A: The techniques that allow very small DNA samples to be useful are well-established and have been the last 15 years. They are the polymerase chain reaction (PCR) and short tandem repeats (STR). Together they are referred to as PCR/STR. The PCR technique basically copies the existing DNA chains so that a single DNA chain–therefore a single cell–can be used to produce as much DNA as is needed. Since the copying is exact, all the DNA produced by this method is identical to the original DNA strand. This process is called amplification but it is basically a duplication of the existing strand. The short tandem repeat is simply a method of analyzing the DNA and producing a profile from multiple short segments of the target DNA.

What this all means is that a very small DNA sample, and theoretically only a single cell, can be used to generate a DNA fingerprint.

 

 
Your other questions bring up a very difficult problem that will be an increasing problem in the future. If the DNA techniques are so sensitive, what do we do about extraneous DNA found at the scene? Since people shed skin cells all the time, a busy public place could theoretically house the DNA from thousands of people. But as with the blues, context is everything.

If the crime scene DNA is found in a drop of blood or a smear of semen or a fingerprint, the DNA found in that sample would belong to the person that left the sample behind. Could it be contaminated by other DNA? Of course, but this contaminant would be in very small amounts. In addition, the extraneous DNA might belong to a family member or friend or someone who had a reason to be at the scene before or after the murder. That’s not always true in the case of the killer. Often he has no innocent reason for having deposited his bodily fluids or fingerprints at a murder scene.

So let’s look at a scenario such as this: the killer does his deed. He washes his hands in the sink. He uses a hand towel to dry his hands. The crime lab technicians evaluate the towel and find DNA present. The DNA proves to be from several people. The victim, the victim’s spouse, the victim’s children, and maybe the victims next-door neighbor who visits daily. But another DNA is found. One that cannot be matched to any known individual. Later a suspect is identified and indeed this DNA matches him.

What does this evidence tell investigators? It tells them what any evidence does. That the individual identified by the DNA had contact with that towel. That’s it. It doesn’t say anything else. This is true of all evidence. It merely serves as a link between a person and another person, place, or object. Your investigators must then uncover the circumstances under which this person’s DNA was left on that towel. If he can prove he had been there for dinner the night before and had indeed washed his hands then this evidence is of little value. But if he swears that he doesn’t know the victim and has never been in the victim’s home, that’s an entirely different story. Again, context is everything.

 

 

New Rapid DNA Technology

The recent killing of Osama bin Laden and the very rapid determination of his identity through DNA and other techniques has generated a great deal of discussion on just how fast DNA analyses can be done. The facts are that with good samples a DNA profile and its matching against a known profile can be done in a few hours, perhaps as little as two or three. But there’s new technology on the horizon that might reduce this time to less than an hour and, just as important, allow this testing to be done in the field by non-specially-trained individuals.

Network Biosystems (NetBio) is the creator of this portable instant DNA scanner that utilizes microfluidics, a rapidly expanding technology that makes use of very small volumes of liquids and microcapillary tubes. Since it is portable, rapid, and doesn’t require a scientifically-trained operator, it will no doubt prove to be a valuable forensic tool.

Lab on a Chip (LOCAD)

I first learned about this technology a couple years ago when I spent time with Dr. Lisa Monaco at NASA’s Marshall Space Flight Center in Huntsville, AL. She explained the microfluidic technology she employs in her Lab-on-a-chip (LOCAD) research and indeed one of her devices is currently roaming around Mars, seeking evidence of nitrogen, oxygen, water, and other chemicals, as well as the amino acids required for life.

Dr. Lisa Monaco

Whether on the surface of Mars or at a crime scene, this technology has a bright future and I suspect we will see an increasing number of uses for it.

 
 
 
Follow

Get every new post delivered to your Inbox.

Join 2,456 other followers