Sunday, August 12, 2007

SF physics and Forensic info

SF Physics and SF Forensics for writers

Fantasy Physics of Star Trek & Bad SF Physics in Movies

The following websites look at the Fantasy Physics of Star Trek.
Lots of good stuff here,

www.physicsguy.com/physandtrek/index.html

members.aol.com/emmagic/private/physics.htm

ssdoo.gsfc.nasa.gov/education/just_for_fun/startrek.html


INSULTINGLY STUPID MOVIE PHYSICS

Here at www.intuitor.com/moviephysics/

More informational/educational websites you might want to check out regarding the basic physics and mechanics of space flight and bad science often used in SF movies.

www.badastronomy.com/bad/movies/spacecowboys2.html

www.badastronomy.com/bad/movies/#list



Trajectories.

When you're trying to intercept another moving object in space with
your space vehicle, you need to calculate the flight plan of the object
you're chasing and figure out WHERE it will be and plot the correct course or trajectory to intercept it.

Then, when you intercept it, you need to match speeds with the
object. At that point it may look to you like you're not moving but
you are. Both ships are now moving together at exactly the same speed.

Here's a very simple simile. Take a merry-go-round. You want
to intercept it at a certain point and jump on it to join one
of the passengers. How do you do this? Do you run straight at the
merry go round and jump on hoping you won't break your neck? Or do you
run alongside of the merry go round until your speed matches it
then jump on?

Each option requires a ton of subsconscious and instinctive calculation of trajectory as you aim to intercept the merry go round at a specific point.

Even if you're writing Space Fantasy/ Space Opera, you still have
to follow some of the basic conventions of flight in space or it'll
bomb, IMHO. Which means, you need spacesuits and space ships
can't STOP DEAD in space, they COAST when the engine power is cut.

The Earth continues to move through space. The moon continues
to revolve around the Earth. The Space Station parked in its
orbit continues to move in order to maintain its position at one
location above Earth.

Definition and general information about trajectories HERE:

www.hq.nasa.gov/office/pao/History/conghand/traject.htm


science.nasa.gov/faq/faq.htm#anchor156390


General thoughts about warp drives here at this website.

www.nasa.gov/centers/glenn/research/warp/warp.html


Another odd factoid is that astronauts have to wear diapers and use catheters in spacesuits if they have to wear them for hours and days at a time.

Here's a website that details how Spacesuits work
inventors.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=inventors&zu=http%3A%2F%2Fwww.howstuffworks.com%2Fspace-suit.htm


If you're in the mood for reading, here's a 28 page very detailed pdf article about spacesuits that includes lots of pictures and diagrams.
history.nasa.gov/spacesuits.pdf



This is one of the reasons why I created selkieskins as bioengineered symbiotic spacesuits for my Sidhe series and for my book The Huntress. It's a lot nicer than wearing one of our spacesuits. LOL.

Why is a lit candle on a space ship a big SF blooper? Is it because of the oxygen content? Does this apply only to space ships nowadays or to space ships in the future as well?


The answer to this question involves the oxygen content inside spaceships and would also apply to the oxygen content inside future spaceships.

Why?

Two reasons:

Reason #1 involves 'da bends' or decompression sickness in space and high altitude flying. The easiest way to avoid decompression sickness is to flood the body and blood cells with a high concentration of oxygen and to maintain this concentration by having an atmosphere inside the spacecraft that has a higher than normal amount of oxygen.

Many people are not aware that decompression sickness or 'da bends' is a very dangerous reality for astronauts.

FAA OFFICE OF AVIATION MEDICINE
CIVIL AEROMEDICAL INSTITUTE
PUBLICATIONS
ALTITUDE-INDUCED DECOMPRESSION SICKNESS
www.2pi.com/les/flying/faa_400altitude.html

The space shuttle is normally pressurized at 14.7 psia (pounds per square inch absolute) or one atmosphere, which is equivalent to sea level pressure on earth. The pressure in the EVA suits is deliberately kept lower-only 4.3 psia or about one third of an atmosphere-to maintain the flexibility the astronauts need to do their work. If the suit pressure were higher, it would be like trying to work inside an inflated balloon.

Reducing the risk of decompression sickness

On the shuttle, a staged technique is used to reduce the astronauts' risk of decompression sickness. First, the astronauts who are doing the EVA prebreathe pure oxygen for an hour, which starts to flush nitrogen from their tissues.

Next, the shuttle's pressure is reduced to 10.2 psia for a minimum of 12 hours-and, in practice, for an average of about 38 hours-before the EVA begins, creating conditions that facilitate further loss of nitrogen from the tissues during that time. Because it's inconvenient for astronauts to continue wearing the mask needed to prebreathe oxygen for 12 hours or more, they go off pure oxygen at this point and breathe slightly oxygen-enriched air containing 26.5% oxygen. Finally, an hour before the EVA, the crew members get into their suits and prebreathe pure oxygen again. If the shuttle's pressure couldn't be reduced for some reason, they'd have to prebreathe oxygen for much longer periods.

(This is another reason why I created the selkieskin spacesuits for my stories. The selkieskins are bio-engineered symbiotes that automatically adjust to the different air pressures just like whales adjust to the different pressures in the ocean and can do deep dives and surface without any problems. I consulted with a ex-NAVY SEAL when I wrote The Huntress. When I explained the concept and abilities of my imaginary selkieskins, the look on his face was like a knight seeing the Holy Grail. )

Reason #2 Any spark of fire inside this type of high oxygen content atmosphere means a very high danger of deadly flash fires.

Here's a chronological series of events and notations from NASA files that illustrates the dangers of the atmosphere inside a spacecraft and why you can't have a lit candle, let alone a lit cigarette inside them.

On January 27, 1967, during a simulated countdown for mission AS-204, a fire inside the command module resulted in the deaths of the three prime crew astronauts, Virgil I. Grissom, Edward H. White II, and Roger B. Chaffee.

January 31, 1967
Col. Charles F. Strang advised the Apollo 204 Review Board of an accident in an altitude chamber at Brooks Air Force Base, Tex., that morning. A flash fire had swept the oxygen-filled pressure chamber, killing Airman 2/C William F. Bartley, Jr., and Airman 3/C Richard G. Harmon. Col. Strang presented a short briefing on the circumstances and was asked by Chairman Floyd Thompson to provide follow-up information.

Lt. Col. William D. Baxter, Air Force Eastern Test Range representative to the Board, advised the group of existing Apollo spacecraft hazards, including:

* high-pressure oxygen bottles that might be pressurized to 335 newtons per square centimeter (485 pounds per square inch) and be subject to embrittlement;
* pyrotechnics on the service module; and
* a launch escape system with a 40-kilonewton (9,000-pound-thrust) rocket motor.


February 27, 1968
NASA officials testified in an open hearing of the Senate Committee on Aeronautical and Space Sciences on the Apollo 204 fire. MSC Chief of Center Medical Programs Charles A. Berry reported that the cause of the three astronauts' deaths could be refined to asphyxiation from inhalation of carbon monoxide, bringing unconsciousness in seconds and death rapidly thereafter. The astronauts were believed to have become unconscious 18 to 20 seconds after the fire began.


FORENSIC INFO for SF writers.

Here are a couple of websites that I find useful. Beware, though: Some of these contain very graphic photos & images.

The Writers Medical and Forensics Lab (Dr. Doug Lyle has been a huge help to many mystery writers on questions of forensics and autopsies.)
www.dplylemd.com


Description of how an autopsy proceeds:
web2.iadfw.net/uthman/Autop.html


www.mysterywriters.org/pages/resources/links/crime.htm#autopsy


www-medlib.med.utah.edu/WebPath/webpath.html#MENU


www.crimelibrary.com/


If you want to know what happens to a dead body in space, go to this webpage.

www.madsci.org/posts/archives/apr2000/956328615.Ot.r.html

Thank you for reading my blog. Hopefully, I’ve helped other Science Fiction writers.

Barbara K.
www.sff.net/people/selkiewife
www.myspace.com/barbarakarmazin
groups.yahoo.com/group/TheSensuousAlien

4 comments:

  1. Have you seen this new spacesuit design from MIT?

    "Instead of using gas pressurization, which exerts a force on the astronaut's body to protect it from the vacuum of space, the suit relies on mechanical counter-pressure, which involves wrapping tight layers of material around the body. The trick is to make a suit that is skintight but stretches with the body, allowing freedom of movement."

    ReplyDelete
  2. I heard about this design. I wasn't sure how far along they were in developing it. From what I heard, they were developing it for a manned mission to Mars.

    If they work out all the bugs in this design, this type of spacesuit would be a lot more comfortable and easier for spacers to move around in zero and low g situations.

    Barbara K.

    ReplyDelete
  3. It's great to see a change in the underlying physics used to design suits. That's a big step forward.

    They think it'll be ready in about 10 years. It could make current space projects (lunar landings, space station repairs) easier by improving astronauts' mobility. It could also make new kinds of space exploration possible.

    "Current spacesuits could not handle the challenges of [an expedition to Mars], Newman says."

    ReplyDelete
  4. All I know is that by the time they improve the spacesuits and improve space travel, I'll be too old to try it. LOL.

    That's why my favorite method of space travel is through my imagination whenever I create my erotic SF books.

    On the other hand, I'll continue to be immensely thrilled and supportive of continued progress and success in space travel and exploration.

    ReplyDelete