Space Flashcards
The force wt which the aviator is pressing against the seat
+1 G
Equal to the pull of gravity, equal to his weight
The force the aviator presses against his seat during pull-out from a dive
+5 G
Force if the airplane goes thru an outside loop
- G
If force wt which person is held down by his belt is equal to the wt of his body : -1 G
Effects of Centrifugal Acceleratory Force on the Circulatory system ( +G)
Blood is centrifuged toward the lowermost part of the body
As pressure in the vessels of the lower body increases, these vessels passively dilate
Blood is pooled, less is available for cardiac output
Acceleration greater than 4-6 G causes black-out of vision wtn a few secs, and unconscousness shortly thereafter; increased acceleration - death
Circulatory collapse
Effects of Centrifugal acceleratory force on the vertebrae (+G)
Extremely high acceleratory forces = fracture
The degree of postive acceleration that the person can withstand in the sitting pos before vertebral fraction occurs
20 G
Effects of -G on the body (-4 to -5G)
-4 to -5G : intense momentary hyperemia of the head; occasionally, psychotic disturbances lasting for 15-20 minutes as a result lf brain edema
Effect of greater -G on the body
Great -G (-20G): cerebral blood pressure reaches 300 to 400mmHg, causing small vessels on the surface of the head and in the brain to rupture;
- csf is centrifuged to the head, blood is centrifuged toward the cranial vessels; greatly increased pressure of csf acts as cushioning buffer to prevent intrecerebral vascular rupture
- intense hyperemia - eyes often become temp blinded wt ‘red-out’
Prevents some of the pooling of blood in the large vessels of the abdomen delaying onset of black out
Aviator tightens his abdminal muscles to an extreme degree and leans forward to compress the abdomen
Prevents pooling of blood in the lower abdomen and legs
Special anti G suits
Simplest form- applies (+) pressure to the legs & abdomen by inflating compression bags as the G increases
Types of linear acceleration
Blast-off acceleration (+) Landing acceleration ( -)
What position can withstand great acceleration (9G - 8G) with ease?
Semireclining pos (transverse to the axis of acceleration)
Reclining seats used by astronauts
The speed of sound and of fast airplanes
Mach 1
can be safelet decelerated in about 0.12 mile
a speed possible in interplanetary space travel
Mach100
10,000 miles for safe deceleration
Deceleration must be accomplished much more slowly from high velocities than is necessary at lower velocites
A human being can w/stand far less deceleration if the period of deceleration lasts for a long time than for a short time
The total amt of energy that must be dispelled during deceleration is proportional to the square of the velocity