Angelfire
2002 Reduced Gravity Student Flight Opportunity Program
Test Equipment Data Package (TEDP)
June 6, 2002
Project # 2002-036:
Testing the Physiological and Psychological Side Effects of Superficially Inducing Earth’s Gravitational Pull on a Human Subject in Microgravity Conditions
Principal Investigator:
Name: Courtney Fritz
E-mail: courtneyfritz@
Voice-mail & Fax: (866) 365-8138
Research Organization:
Name: Austin Community College- Rio Grande Campus
Address: 1212 Rio Grande St., Austin, TX 78701
Phone (Dr. Underwood, Faculty Sponsor): (512) 223- 3299
6.2. KC-135 Quick Reference Data Sheet
Principal Investigator: Courtney Fritz
Contact Information: E-mail: courtneyfritz@ ;Voice-mail/Fax: (866) 365 - 8138
Experiment Title: Testing the Physiological and Psychological Side Effects
of Superficially Inducing Earth’s Gravitational Pull on a
Human Subject in Microgravity Conditions
Flight Date(s): 07/24 - 07/25/2002
Overall Assembly Weight (lbs.): 124.2 lbs
Assembly Dimensions (L x W x H): 54 x 24 x 42 1/4 inches
Equipment Orientation Requests: Long axis of assembly aligned fore-aft, on
starboard edge of fuselage
Proposed Floor Mounting Strategy (Bolts/Studs or Straps): Bolts/Studs
Gas Cylinder Requests (Type and Quantity): None, No gas cylinders required
Overboard Vent Requests (Yes or No): No, no vent required
Power Requirement (Type and Amps Required): Standard 115 VAC, 60 Hz, 3 Amps
Flyer Names for Each Proposed Flight Day:
(07/23/02) Courtney Fritz (07/23/02) Tom Harley Stenis
(07/24/02) Andrea Pearlman (07/24/02) Keith Gilligan
(Alternate) Julia Braulick
6.3. Table of Contents
1) Cover Page
2) Quick Reference Sheet
3) Table of Contents
4) Flight Manifest
5) Experiment Background
6) Experiment Description
7) Equipment Description
8) Structural Analysis
9) Electrical Analysis
10) Pressure Vessel Certification
11) Laser Certification
12) Parabola Details and Crew
Assistance
13) Free Float Requirements
14) Institutional Review Board (IRB)
15) Hazard Analysis
16) Tool Requirements
17) Photo Requirements
18) Aircraft Loading
19) Ground Support Requirements
20) Hazardous Material
21) Material Safety Data Sheets
(MSDS)
22) Procedures
23) Bibliography
1
2
3
4
4
5
6
8
16
31
31
31
32
32
32
35
35
35
36
36
36
36
39
6.4. Flight Manifest
Student Flyer: Courtney Fritz
Preferred Flight Date: 07/23
KC-135 Flight Experience: None
Student Flyer: Tom Harley Stenis
Preferred Flight Date: 07/23
KC-135 Flight Experience: None
Student Flyer: Keith Gilligan
Preferred Flight Date: 07/24
KC-135 Flight Experience: None
Student Flyer: Andrea Pearlman
Preferred Flight Date: 07/24
KC-135 Flight Experience: None
1 Experiment Background
This particular experiment is a collegiate level attempt to counteract some of the mal-effect of long-term exposure to microgravity conditions. Many changes have been witnessed to take place in the body when forced to live in an environment of apparent “zero gravity.”
Several physical aspects of these bodily changes, as observed throughout the decades of space travel and experimentation, include bone demineralization (whereby calcium mobilizes into serum released by the body), muscle atrophy[1], reduced neuromuscular coordination, post flight orthostatic intolerance, and post flight reduced upright exercise capacity[2]. The afore mentioned reduced neuromuscular coordination has also been known to cause a period of confusion, (resulting from conflicting sensory signals upon entering microgravity known as an “autonomic storm”) often resulting in nausea and disorientation[3], which is frequently referred to as Space Adjustment Syndrome (SAS)[4].
In addition to these physical ailments that current space travelers must incur, there are psychological stresses that one must overcome to function in orbit and interplanetary travel. The sensory system of the body, made up of linkages between visual, somatosensory, and vestibular perceptions, is most often established through “experience of inertial and gravitational reaction forces.[5]” When one’s orientation is altered in an environment vastly different from that which they have established the basis for orientation, stress and panic often occur[6]. An astronaut not capable of handling their situation/environment will most likely perform with less accuracy and expediency than that of a well-adjusted astronaut.
It seems logical that allowing a human space traveler to remain in an environment as close fitted to Earth’s as possible would be beneficial. However, due to the current limitations in technology/innovation that have not allowed us to completely reproduce an artificial environment identical to that of Earth’s, this project focuses on artificially creating a single aspect of Earth’s environment (gravity).
Due to the connections between the human sensory system (see above), it may be possible to induce a stimulus on the body which simulates the effects of gravity and decreases the amount of conflicting sensory input. In addition to the possibility of aiding the stress of space travel and SAS symptoms, a consistent compression on the musculoskeletal system of the body may combat bone demineralization and muscle atrophy. Though this current apparatus is not in active use on board all space flight expeditions, a compression harness is not an isolated concept. In the previous decades of space travel, many significant attempts at combating the malignant effects of microgravity were made[7], including Russia’s “ Penguin Suit”[8] (Pengvin Suit) [9].
The difference between our compression harness and the Russian Penguin Suit is that, rather than attempting to influence blood pressure in addition to the musculoskeletal system, this stimulus concentrates on the superficial compression of the body and is designed to create a state of comfort as close to an actual 1-g environment as possible.
Due to the fact that the KC-135 does not allow for periods of long-term weightlessness, this particular study concentrates on the physiological and psychological side effects of using this harness (during short periods of apparent zero-g). Our testing concentrates on a measurable analysis of real-life applicable traits/situations that may come into play throughout space travel. Four categories: physical orientation/dexterity, mathematical ability, memory, response time (see experiment description)[10]. This testing will be used to formulate qualitative data regarding performance under the influence of stimuli (or lack thereof)[11].
5. Experiment Description
This study will be the initial flight of our project, composed of two main portions (a physical stimulus and an experimental process). It is our hypothesis that inducing a superficial physical stimulus on the body approximately that of 1-g (while being subjected to microgravity) will assist in re-orienting the body’s sensory equilibrium. Thus, the symptoms related to Space Adjustment Syndrome will be decreased (i.e., stress, nausea, disorientation, vertigo, and infrequent but sudden vomiting).
The effectiveness of the stimulus, achieved through elastic compression of the musculoskeletal system at the approximate force of the subject’s weight on Earth, will be tested by way of 3 interactive computer programs and 1 physical procedure. These 4 tests are designed to test four major components of performance (see Experiment Background): physical orientation/dexterity, mathematical ability, memory, response time.
6.6.1. Physical Orientation/Dexterity; “Cylinder Probe Test”:
The subject’s ability to correctly orient themselves as desired will be tested with a “Cylinder Probe Test.” This test is designed to concentrate on a common action that is likely to be necessary for an astronaut to perform while in microgravity conditions. The subject is instructed to insert a conductive probe into a conductive cylinder with the goal of touching ONLY the separately conductive disc at the bottom of the cylinder. To measure the subject’s ability in coordination and agility, a computer program will record the frequency of successful and unsuccessful insertions.
6.6.2. Mathematical/Cognitive Ability
A computer program will test the subject’s ability to perform cognitive tasks in the stresses of microgravity conditions. The subject will be given relatively simplistic multiple-choice problems that successively increase in difficulty.
Example:
Question 1: 5*9 = Question 2: 144^(1/2) =
a)25 b)72 c)45 d)81 a)12 b)7 c)11 d)72
6.6.3. Memory
Another computer program displays (for a set time) a series of approximately 10 letters in random order. Once the set time expires the subject is required to re-enter the previously displayed letters in as numerous and accurate an order as possibly, within the limitations of an allotted amount of time.
6.6.4. Response Time
A final computer program will measure the time elapsed between a displayed visual stimulus and the subject’s physical response. The subject is shown a particular symbol which is designated as a ‘visual stimulus,’ at which time the subject is then instructed to press an pre-determined ‘termination’ key once he/she identifies the displayed ‘visual stimulus.’ After a random delay of duration 0-30 seconds, the computer program will display the ‘visual stimulus’ and simultaneously begin timing the subject’s response. Timing will terminate once the subject’s physical response is complete (pressing the ‘termination’ key).
A control variable will be established for all testing in addition to ground-based experiments. First, prior to travel to Houston, all test subjects (see Flight Manifest) will perform the previously described (4) tests on the ground, under regular 1-g compression, with no artificial compression. Due to the fact that the harness being tested is designed to duplicate the comfort of 1-g compression, these ground-based results will act as a level of comparison for any and all results received during flight experimentation. Secondly, the in-flight control variable for our experiment will be achieved by recording results of the subject under no compression for half of the KC-135 parabolic flights. Finally, all uncontrolled variable experimentation will be accomplished by recording results from the afore mentioned (4) tests while wearing a fully compressed harness that is calibrated to approximately their bodily weight on Earth.
We anticipate that all ground-based results recorded will show that the test subjects perform their greatest while in their natural environment (1-g). It is also expected that the results from experimentation with the uncontrolled variable (fully compressing harness) will more closely resemble the previously recorded ground-based results rather than the control variable (in-flight) results.
It is our hope that this device could be applicable in real life situations in the future. For instance, while the current exercise regiment of an astronaut in orbit consists of a minimum of 1 hour daily and has been calculated as insufficient to maintain “preflight musculoskeletal mass[12],” a consistent 1-g compression on the body may lessen the necessary time for exercise (thereby increasing productivity). The afore mentioned device may also be used as an affective countermeasure to the debilitating effects on the human body resulting from long term exposure to microgravity conditions. In addition to a time saving and physically therapeutic apparatus, this compression harness could also prove to be capable of directly increasing comfort levels and performances of astronauts by acting on them with a force similar to that of their home planet (decreasing the stress and anxiety due to lack of sensory orientation).
6.7. Equipment Description
1. Ground Based Equipment
not applicable
2. Equipment For In-Flight Operations
Fixed Experiment Assembly
Composed of elastic (theraband) material restrained by non-elastic (polyester) frame/harness, our compression harness can be worn by the test subject at all times as either ‘clipped’/compressing or ‘unclipped’/no compression.
Side release clips are attached to the end of each band of theraband elastic via ‘D’ rings. When a subject wishes to feel compression, each separate portion of elastic may be extended and secured into its compressive state by ‘clipping’ it into place.
Figure a: Front view[pic]
Figure c: Front view, Close up of ‘clipped’ Theraband
[pic]
The compression force of the harness is distributed about the shoulder via the surface area of leather shoulder pads, coushined with padded material. A ‘right-handed-quick release’ is attached to the front chest of the harness.
[pic]
Figure d: Quick release opens
To avoid free floating fragments of broken elastic, should the physical integrity of the Theraband fail, all elastic is enclosed in a denim membrane that can be sealed or accessed on both ends with a draw-string.
[pic]Figure e: Denim membrane
[pic]Figure f: Back Torso, Draw-String Access
The experiment assembly consists of two welded steel three-shelf lab carts bolted together end-to-end, and bolted to a 2 ft x 4.5 ft x ¼ in. aluminum base plate, which will be bolted to the aircraft frame. The lab cart test assembly supports and restrains the experimental equipment and provides a work surface for the crew to perform their measurements. A top shelf layer running the entire length (48.5 in ) of both carts consists of 3/8 inch plywood work surface atop a slotted steel angle shelf frame projecting approximately 1 foot above the top (3rd) shelf of the lab carts. The plywood shelf and attachments support and restrain the two test computers and the top section of the probe-cylinder dexterity test assembly. The next lower layer of shelves accommodates the main power strip, the computer power adapters, the lower section of the probe-cylinder dexterity test assembly, and the two Pasco PasPortTM USB Link A/D converters with associated voltmeter and accelerometer sensors.
The conductive probe, a part of the probe-cylinder test assembly, will be used by the flight crew when they conduct the dexterity test to measure their success rate at touching the bottom of a conductive cylinder without making contact with the sides. The probe connects to the top section of the test assembly similarly to the way a phone handset is connected to the base of the phone. In addition to the ( non-load bearing ) thin coiled connector, the probe will also be tethered to the test assembly with a length of braided fishing line running co-axially with the handset cord, and of sufficient strength to provide ample safety factor to restrain the probe under the design g-load conditions. The probe itself is of very low density construction for safety considerations, based on thin plastic soda straws covered with a conducting layer. When not in use the probe will be parked in a Velcro holster attached to the side of the test assembly.
Component Weights
Metal Frame Assembly: 96.0 lbs (includes 2 ft by 4.5 ft base-plate)
Plywood shelf: 6.0 lbs
Computer 1: 5.5 lbs
Computer 2: 5.0 lbs
Computer bracing: 2.9 lbs
Top cylinder housing: 2.5 lbs
Bottom cylinder housing: 2.0 lbs
Power strip: 2.9 lbs
Computer 1 power adapter : 1.0 lbs
Computer 2 power adapter : 0.9 lbs
Voltmeter and A/D: 0 .5 lbs.
Accelerometer and A/D: 0.3 lbs.
Total: 125.5lbs.
Table 6.7.1 Experiment Assembly Components and Materials
[pic]
Figure 6.7A Equipment Layout-top layer
[pic]
Figure 6.7B Component Placement- Second Shelf
[pic]
Figure 6.7.C Probe Assembly Detail
[pic]
Figure 6.7D Placement in Aircraft
OTHER EQUIPMENT
In addition to the two elastic harness assemblies worn by the crew members over their flight suits the researchers will bring aboard a 12 gauge power extension cable for connecting the main power strip to the aircraft power panel, two Pasco Explorer portable datalogging units with attached heart rate monitor sensors to be worn on the persons of the flight test subjects, a video camera for mounting on a (RGSFOP/NASA -provided ) camera pole, a clipboard and pens, duct tape, a spare 9 V battery, 4 spare AA batteries, a spare camera battery, spare ½ amp fuses, a spare 1 hour DV tape, a spare conductive probe and spare tether cord for the probe. The camcorder is a Canon Optura , of weight approximately 2 lb, of dimensions 57/16 x 43/16 x 51/4 in. It is powered by an internal 7.2 V DC rechargeable lithium ion battery of capacity 1350 mAh. At an operating power consumption rate of 7.1 watts the battery pack will be able to power the camera for approximately 1 hour 25 min. The spare items will be kept on the persons of the flight crew and in a small covered canvas bag to be secured by strap to the middle shelf of the frame.
6.8 Structural Analysis
6.8.1 Free Body Diagrams
[pic]
[pic]
[pic]
6.8.2 Component Weights
| | | | |
|Component and overall assembly weights | | | |
| | | | |
|component | | | |
|item name | | | |
|weight (lb) | | | |
|fasteners | | | |
| | | | |
|A | | | |
|Computer 1 | | | |
|5 | | | |
|1/16 in. aluminum angle bracing, | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|3/8 in.plywood monitor stand | | | |
| | | | |
|B | | | |
|Computer 1 bracing | | | |
|1.4 | | | |
|2 8-32 machine screws/brace element, | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|1/16 in steel t-strap w/ 2 3/8 in. bolts | | | |
| | | | |
|C | | | |
|Computer 2 | | | |
|5.5 | | | |
|1/16 in. aluminum angle bracing, | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|3/8 in.plywood monitor brace | | | |
| | | | |
|D | | | |
|Computer 2 bracing | | | |
|1.4 | | | |
|2 8-32 machine screws/brace element, | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|1/16 in steel t-strap w/ 2 3/8 in. bolts | | | |
| | | | |
|E | | | |
|probe assembly-upper layer | | | |
|2.5 | | | |
|4 8-32 machine screws, | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|two 3/4 in. wide webbing straps | | | |
| | | | |
|K | | | |
|probe assembly-lower layer | | | |
|2 | | | |
|4 SAE-2 1/4" bolts | | | |
| | | | |
|F | | | |
|power strip | | | |
|2.9 | | | |
|2 SAE-2 1/4" bolts | | | |
| | | | |
|G | | | |
|power adapter-Computer 1 | | | |
|1 | | | |
|two 3/4 in. wide webbing straps | | | |
| | | | |
|H | | | |
|power adapter-Computer 2 | | | |
|1 | | | |
|two 3/4 in. wide webbing straps | | | |
| | | | |
|L | | | |
|voltmeter sensor and USB Link | | | |
|0.5 | | | |
|1 SAE-2 1/4" bolt | | | |
| | | | |
|M | | | |
|accelerometer sensor and USB Link | | | |
|0.3 | | | |
|1 SAE-2 1/4" bolt | | | |
| | | | |
|N | | | |
|welded and bolted steel frame | | | |
|68 | | | |
|8 SAE-5 3/8" bolts | | | |
| | | | |
|O | | | |
|aluminum baseplate ( to airframe) | | | |
|28 | | | |
|6 NAS-3 3/8" bolts | | | |
| | | | |
|P | | | |
|3/8 in plywood top shelf | | | |
|6 | | | |
|16 SAE-2 5/16" bolts | | | |
| | | | |
| | | | |
| | | | |
| | | | |
| | | | |
| | | | |
|Total | | | |
| | | | |
|125.5 | | | |
| | | | |
| | | | |
Design Calculations
Components to Frame
Throughout most of this section we do not include the analysis for the 3g aft loading, since the 9g forward loading will always give smaller safety factors ( by a factor of 3 ) because of the forward-aft symmetry of most of the equipment and support structures.
Upper Probe Assembly:
This unit , of weight about 2.2 lbs, is secured by four 8-32 machine screws and two perpendicular lengths of polypropylene web belt to the top plywood shelf. The reactions in all directions created by the design g-loading is far less than the tensile strength of > 1000 lbs of the webbed belt, not even taking into account the added strength due to the 4 screws. Safety factors in all directions of over 100 result.
Lower Probe Assembly:
This unit , also of weight of weight about 2 lbs, is secured by four 1/4 in. SAE-2 steel bolts through the bottom of the assembly to the steel shelf below the top plywood shelf. These bolts have a combined shear yield strength of over 5 kips and a safety factor of over 100. Likewise for the 2g upward ( tensile ) loading.
Laptop Computers:
The computers are restrained along their fronts and sides by bracket attachments constructed of 1/16 in. thick, 1 in. wide aluminum angles attached to the plywood top shelf by 8-32 machine screws and nuts. The rear of the computers ( oriented toward the 2g side direction ) is each restrained by a plywood and steel brace bolted to the plywood shelf and attached to the computer screen edges. The worst case is the 9g forward loading, where the two involved screws provide a safety factor of about 50. For the 6g down condition, the approx. 5 lb weight of each computer is distributed over a shearing area of 16 in2 of the 3/8 in. plywood. Under 6g this provides about 2 psi of shear stress. The plywood can be safely loaded to over 100 psi in shear, giving safety factors of about 50. Other items on the plywood present lower shear stress demands on the plywood and will not be analyzed for the 6g down condition.
Computer Bracket Attachments:
These are held in place by the machine screws referred to in the previous paragraph. They are each composed of two angle pieces bonded together with JB Weld. The only condition that exerts stress against these bonds is the upward 2g loading on the computers, placing them in shear. JB Weld has a tensile strength of 3960 psi, so with a bonded area of several in2 we get a safety factor far greater than 100.
Power Strip:
This weighs 3 lbs and is secured by two ¼ in. SAE-2 bolts each with estimated tensile yield strength
in the range of 2000 lb each, and shear yield of about 950 lb. Minimum safety factor here is about 75. We have estimated the shear stress on the steel shelf below the power strip in the 6g downward loading, based on the 1/16 in. thickness of the shelf and the geometry and weight of the power strip to be in the range of 10 psi. Conservatively, the shear yield stress for the steel is in the range of 30,000 psi at a minimum, with a safety factor far greater than our needs. Other items on the steel shelves present lower shear stress demands on the steel and will not be analyzed for the 6g down condition.
Computer Power Adapters:
These are restrained by poly webbing like the upper probe assembly, but are lighter. Safety factors are > 50.
Accelerometer and Voltmeter Sensor Units:
Each of these is bolted to the steel cart shelf by a single ¼ in. SAE-2 steel bolt to which the units are factory designed to attach. The units would disintegrate internally long before the bolts would give.
Full Assembly
Aluminum base plate of frame:
The base plate is attached to the factory welded steel frame by 8 SAE-5 3/8 inch bolts bolted to cylindrical steel collars factory welded to the 8 angle steel legs of the frame. Failure could occur by bolt failure, weld failure, or base plate material failure.
For 9g forward loading the average shearing force per bolt is about 110 lbs. The shear yield strength of each of these bolts is several thousands of pounds, giving a safety factor between 10 and 100. Even greater safety factors obtain for the 2g side loading. The same goes for the 2g up-loading restrained by the 8 bolt hex caps.
The strength of the welds on the collars can be estimated (1) by use of the formula
[pic]
where φ is the resistance factor , FW the nominal strength of the welding electrode, and AW the effective cross sectional area of the weld. Conservatively, for these welds φ ~ 0.75. AW equals the length of the weld times the effective throat thickness ( see diagram below) . With an outer radius R of approximately 5/16 in and a weld length of 1.5 in this gives AW= 0.15 in2. For this type of weld FW = 0.6 FEXX, where FEXX= the classification strength of the weld metal, conservatively estimated at 60 ksi. This gives a tensile strength estimate of the weld of approximately 4000 lb, and a shear strength of 2400 lb. In any lateral direction, at least 4 of the 16 welds would have major involvement via tension, and 8 under shear. For the 9g forward loading of about 1000 lb total this gives a safety factor of around 30. For side loading the safety factors are greater since the loads are reduced while the supports are similar. [pic]
Fig. 6.8.3A welded bolt collars
The aluminum base plate provides support for the approximately 100 lb upper assembly under the 6g downward loading. Using a conservative estimate of 25 ksi for the aluminum tensile yield stress and 15 ksi for the shear yield stess, and a shearing area of 33 in2 under the footprint of the upper assembly one gets a yield load of about 500 kips. This gives a safety factor of over several hundreds.
Lab Carts:
The major part of the of entire workbench/frame is formed from two factory welded heavy-duty lab carts bolted to the aluminum base plate with 8 3/8 in. bolts, and bolted together with six. ¼ in bolts. Other than for the points of attachment of these carts with the various other components that we have added, we do not analyze here the forces internal to these carts. The six ¼ in. bolts connecting the carts are not required, are not subjected to significant stresses, and are therefore not analyzed here, since each cart is individually bolted with four 3/8 bolts to the same base plate, as well as being tied together by the tensile strength of the 3/8 in. plywood shelf across the top. Since the carts are next to each other we have added these bolts for extra rigidity and strength.
Top shelf frame:
This unit is constructed from 1 ½ in. wide 1/16 in. thick slotted steel angle iron bolted onto the tops of the steel frame legs, each secured to each with four 5/16 in. SAE-2 bolts, as shown in the figure below.
[pic]
Fig. 6.8.3B Top Shelf Frame
With the weight of the shelf frame and attached components adding to about 25 lbs, the pertinent g-load forces are 225 lb forward, 50 lb side and up, and 150 lb down. The internal strength of the angles, under bending, shear, etc. is of the same order of magnitude as the angle iron legs of the original lab carts forming the main body of the upper assembly and is not here calculated for that reason. The yield stress of the bolts is estimated at 60 ksi for tension and 36 ksi for shear, so the yield strengths are about 3 kips for tensile yield and about 2.75 kips for shear. The weakest part of the shelf frame, the top edge, is held together by 16 bolts, 8 in shear and 8 axially loaded for horizontal plane g-loading, and all 16 in shear for vertical loading. Minimum safety factors all > 100.
Plywood shelf
The plywood shelf with attached components has a weight of about 20 lbs, and is attached to the slotted angle iron horizontal upper frame edge with sixteen SAE-2 5/16 in. bolts, again with very large safety factors > 100 in all directions. Since the longitudinal axis of all 16 bolts is vertical, all loading is shear for the horizontal g-factors, and tensile for the 2g up- loading.
The smallest safety factors for the plywood shelf plus its load are due to the strength of the plywood itself. We use an allowable stress for plywood for shear through the thickness (2) of value 150 psi. For the 9 g forward loading the effective shear area is 138 in2 , and for the lateral 2g loading the effective shear area is 48 in2. For the 2g up-loading the effective shear area is about 6 in2. These lead to the following lower limits on safety factors:
9g forward: SF > 100
2g lat: SF > 100
2g up: SF ~ 22
The 6g down-load of 120 lb is limited by the plywood shear strength with a shearing surface area of about 66 in2, based on the unsupported regions of the plywood shelf. This gives a safety factor of about 80.
Floor Attachment
The full assembly is attached to the aircraft by six aircraft 3/8 in. floor bolts bolted through the ¼ in. thick aluminum base plate. At 5000 lb tensile yield strength and 5000 lb shear yield strength, and a full assembly weight of 125.5 lb, the safety factors for horizontal and vertical loading on the bolts are as follows:
|9g forward: |SF = 27 |
|3g aft: |SF = 81 |
|2g lat: |SF = 120 |
|2g up : |SF = 120 |
Free Floated Hardware
Not applicable
Floor Load Analysis
The aluminum base plate will rest on 6 spacers, which could tolerate a 1 g load weight of 1200 lb. The entire assembly weighs about 125 lb, giving a safety factor of 9.6.
Safety Factor Table
| | |Safety Factor Table | | | |
|Component | |Load Case |Location | |Safety Factor |
|whole assembly (includes baseplate) |9g forward | | | |27 | |
|* aircraft bolts | |2g lat | |6 bolts, 20 in x 20 in grid, |120 | |
| | |2g up | |on aircraft floor beams |120 | |
|* spacers | |6g down | | | |9.6 | |
|upper assembly | |9g forward | |attached to baseplate |~ 40 | |
|* bolts | |2g lat | |by 8 3/8 " bolts through |> 40 | |
| | |2g up | |1/4 " aluminum plate base |> 40 | |
|* welds | |9g forward | |bolts attach to frame at |~ 30 | |
| | |2g lat | |welded (factory) collars |> 30 | |
| | |2g up | |on frame legs |> 30 | |
|* baseplate | |6g down | |under upper assembly |> 100 | |
| | |9g forward | | | |> 100 | |
|top shelf frame | |9g forward | |bolted to top of each of |~ 100 | |
|* bolts | |3g aft | |8 cart legs by four 5/16" |> 100 | |
| | |2g lat | |bolts per leg |> 100 | |
| | |6g down | | | |~ 100 | |
| | |2g up | | | |>100 | |
|top plywood shelf | |9g forward | |top shelf of upper assembly |> 100 | |
|* bolts | |2g lat | | | |> 100 | |
| | |2g up | | | |>20 | |
|* shelf shear strength | |6g down | |atop shelf frame |~ 80 | |
|laptop computers | |9g forward | |restraints for computer edges |~ 50 | |
|* bracket | |2g lat | | | |> 50 | |
| attachments | |2g up | | | |> 50 | |
|* adhesive | |2g up | |bonds two parts on each |> 100 | |
| | | | |bracket attachment | | |
| | | | |( JB Weld) | | |
|* plywood | |6g down | |holding up the computers |~ 50 | |
|upper probe assembly |9g forward | |on top plywood shelf, |> 100 | |
|* bolts | |2g lat | |between two laptops |> 100 | |
|and webbed belts | |2g up | | | |> 100 | |
|lower probe assembly |9g forward | |middle of 2nd shelf |> 100 | |
|* bolts | |2g lat | | | |> 100 | |
| | |2g up | | | |> 100 | |
|power strip | |9g forward | |forward edge of middle shelf |~ 75 | |
|* bolts | |2g lat | | | |> 75 | |
| | |2g up | | | |> 75 | |
|* steel shelf | |6g down | |supporting strip vertically |> 100 | |
|Computer power adapters |9g forward | |forward half of middle shelf |~ 50 | |
|* webbed belts | |2g lat | | | |> 50 | |
| | |2g up | | | |> 50 | |
|Sensor Units | |9g forward | |aft half of middle shelf |> 100 | |
|* bolts | |2g lat | | | |> 100 | |
| | |2g up | | | |> 100 | |
6.9 Electrical Analysis
6.9.1 Schematics
[pic]
Figure 6.9.1A Lower Shelf Electrical Equipment Block Diagram
[pic]
Figure 6.9.1B Top Shelf Electrical Equipment Block Diagram
Computer 1
Mac G4 notebook computer, Motorola 1 GHz Processor,
256 MB RAM, 20.0 GB hard drive, 13.0" color LCD Screen, UL Listed
Rating: 15 VDC, 2.0 A
Battery Rating: 10.8 VDC, 2500 mAh
Computer 2
Dell Latidude notebook computer, Intel Pentium II 1 GHz Processor,
256 MB RAM, 20.0 GB hard drive, 13.0" color LCD Screen, UL Listed
Rating: 15 VDC, 2.0 A
Battery Rating: 10.8 VDC, 2500 mAh
Voltmeter sensor and A/D
Pasco Passport and USB Link interface, connects to computer via a USB port.
Powered by Computer 1 system bus.
Rating: 5 VDC, 0.6 A (max input)
3-Axis Accelerometer
Pasco Passport 3-Axis Accelerometer sensor and USB Link interface-powered by
Computer 1 system bus.
Rating: 5 VDC, 30 mA ( max input)
Probe-cylinder test assembly circuit
Powered by 9 volt alkaline battery - max current 35 ma
Includes a ½ amp fuse in circuit.
Power Strip
Belkin power strip, acts as master kill switch. UL1449 listed. Includes a 15 amp
circuit breaker.
Rating: 125 VAC, 15 Amps max @ 60 Hz, 330 VAC max suppressed
voltage, 1,875 W max suppressed power.
Camcorders
1 Canon Optura DV Camcorder , powered by 7.2 VDC battery pack
of capacity 1350 mAh. Power consumption 7.1 watts.
Pasco Explorer dataloggers and pulse rate monitors
Each of the two flight crew will carry on his/her person a battery-
powered datalogger pulse rate monitor module. Each is powered by 2 AA 1.5 V
batteries.
6.9.2 LOAD TABLE
|Power Source Details | |Load Analysis | |
|Name: Power Cord A | |Computer 1- 1.5 amps | |
|Voltage: 1156 VAC, 60 Hz | | |Computer 2- 1.5 amps | |
|Wire Gauge: 12 | | | | |
|Max Outlet Current: 20 amps | | |Total current Draw: 3 amps |
The four other powered devices we will carry aboard the flights ( the probe assembly, the camcorder and the two dataloggers/pulse rate monitors ) are all battery powered and do not require load tables.
Emergency Shutdown Procedure
A master kill switch on the main power strip will shut off power to the computers. There is also a master kill switch for the probe test assembly. In case of an emergency the shutdown sequence will be to first shut off power to the computers by throwing the main power strip master kill switch, then shut down the probe test assembly power by throwing the test assembly kill switch, then shut off the camcorder, then power off Computer 1 and Computer 2 which will have by then switched to their internal battery power, finally to turn off the two battery powered dataloggers/pulse rate monitors.
6.9.4 Loss of Electrical Power
If aircraft electrical power is lost the system fails to a safe configuration. The computers automatically switch to battery power. The remaining equipment is battery powered only.
6.10 Pressure/Vacuum System Documentation Requirements
Not applicable
Laser Certification
Not applicable
6.12 Parabola Details and Crew Assistance
Optimally, we plan the first 3 zero-g dips to be devoted to acclimating to the environment, then we have designed the experiment for 12 (outbound ) dips with enough time between dips for the 2 team members to swap positions (see Appendix A ) ; then a brief pause after the 15th dip to allow the 2 team members to either engage or disengage the elastic harnesses they are wearing as the case may be, and to each upload data sets from the personally worn heart rate monitor recorders to Computer 2, then to reset the heart rate monitors. On the way back, a similar set of 12 dips to complete the experiment, then a final 3 dips for photo ops, etc.
The experiment design is a paired difference t-test for each response measured, and requires a symmetric arrangement of cases with and without the stimulus ( wearing the harness ). For this reason it is highly desirable to have the same number of dips on the way out ( say 12 ) as on the way back . If this is not possible because of weather or time constraints it would be very helpful if the flight crew could keep us informed of the changing flight profile as things develop, so adjustments could be made in the test sequence to prevent data from being wasted.
6.12.1 Free Float Requirements
No equipment will be free floating. A tethered and applicably adhered probe will be used (see Equipment Description) and test subjects will be secured at the feet (foot straps) or by hand (handle).
6.13 Institutional Review Board
This experiment requires IRB approval
6.14. Hazard Analysis Report
The experiment uses no chemicals, hazardous or otherwise.
6.14.1 HAZARD CHECKLIST
1. Flammable/combustible material, fluid (liquid, vapor, or gas)
N/A Toxic/noxious/corrosive/hot/cold material, fluid (liquid, vapor, or gas)
N/A High pressure system (static or dynamic)
N/A Evacuated container (implosion)
N/A Frangible material
N/A Stress corrosion susceptible material
N/A Inadequate structural design (i.e., low safety factor)
N/A High intensity light source (including laser)
N/A Ionizing/electromagnetic radiation
N/A Rotating device
2. Extendible/deployable/articulating experiment element (collision)
3. Stowage restraint failure
4. Stored energy device (i.e., mechanical spring under compression)
N/A Vacuum vent failure (i.e., loss of pressure/atmosphere)
N/A Heat transfer (habitable area over-temperature)
N/A Over-temperature explosive rupture (including electrical battery)
N/A High/Low touch temperature
N/A Hardware cooling/heating loss (i.e., loss of thermal control)
N/A Pyrotechnic/explosive device
N/A Propulsion system (pressurized gas or liquid/solid propellant)
N/A High acoustic noise level
N/A Toxic off-gassing material
N/A Mercury/mercury compound
N/A Other JSC 11123, Section 3.8 hazardous material
N/A Organic/microbiological (pathogenic) contamination source
5. Sharp corner/edge/protrusion/protuberance
6. Flammable/combustible material, fluid ignition source (i.e., short circuit; under-sized wiring/fuse/circuit breaker)
N/A High voltage (electrical shock)
N/A High static electrical discharge producer
N/A Software error
N/A Carcinogenic material
Computer bracing breaks or fails
Subject experiences lack of comfort or muscle soreness
6.14.2 DETAILED HAZARD DESCRIPTIONS
Hazard Number 1: Flammable/combustible material, fluid (liquid, vapor, or gas)
Description: Plywood top shelf , computer monitor bracing, and lower probe assembly housing are made of wood are flammable and could catch fire.
Causes: Short circuit in electrical system of experiment.
Controls: All elements of circuitry are either fused or protected with appropriately sized circuit breakers.
Hazard Number 2: Extendible/deployable/articulating experiment element (collision).
Description: Probe on the dexterity test assembly.
Causes: High accelerations or other mishaps could cause the experimenter to lose control of the probe.
Controls: Probe is constructed of extremely low density material- which is unlikely to cause injury even under direct impact. In addition, the probe is restrained by a sufficiently strong tether.
Hazard Number 3: Stowage restraint failure.
Description: Canvas bag for spare items .
Causes: Accelerations or other mishaps could cause the bag to become disconnected from cart.
Controls: Restraining straps will secure the canvas bag with triple redundancy.
Hazard Number 4: Stored energy device
Description: Elastic harnesses on test subjects
Causes: Control of elastic straps could be lost as test subjects are attaching or detaching straps during mid-flight , injuring test subjects as elastic recoils.
Controls: Elastic strapping is securely fixed to the base of the harness on a non-elastic rail system and contained within a non-elastic membrane. Test subjects only engage or disengage straps once during the entire flight.
Hazard Number 5: Sharp corner/edge/protrusion/protuberance
Description: The metallic and wooden edges of the test assembly
Causes: Test subjects could impact against test assembly
Controls: Test assembly will be padded and taped at all sharp or protruding edges.
Hazard Number 6: Flammable/combustible material, fluid ignition source (i.e., short circuit; under-sized wiring/fuse/circuit breaker)
Description: Wiring and circuitry of test assembly
Causes: Spark or fire from short circuit or undersized wires
Controls: Sufficiently low-gauge wiring is used throughout electrical equipment. Circuits protected by fuses and/or circuit breakers. Currents are minimal and of signal strength only, except for computer and sensor power sources.
Hazard Number 7: Computer bracing breaks or fails.
Description: Computer bracing
Causes: The bracing could fail , causing the computer(s) to come loose and fly away from assembly.
Controls: The computer restraints are designed with very large safety factors, as described in the section on the structural analysis.
Hazard Number 8: Human test subjects experience lack of comfort or muscle soreness.
Description: Test subjects experience discomfort or soreness due to flight activities and the harnesses they will be wearing.
Causes: Experiment activities may incur test subject discomfort due to improper adjustment of harness.
Controls: Subjects will have undergone extensive physical conditioning and training with the harnesses, on trampolines and neutral buoyancy tanks, prior to flight.
6.15. Tool Requirements
1. TOOLS BROUGHT BY TEAM
We will need a small assortment of wrenches and screwdrivers and a rachet and socket set and a pair of pliers to secure the computers to the test cart prior to the flights and to remove them after the flights, as well as to tighten any of the bolts or screws on the test assembly prior to the flights. Tools are not required during flight.
Tools will be labeled "ACCMFT and marked with a color code marking and will be contained in a pouch. We will provide a pre-flight check-off list to insure that all tool components are removed from the aircraft and accounted for prior to the flights.
2. TOOLS REQUESTED FROM JSC
Tools for bolting the aluminum base plate of the test assembly to the floor of the KC-135A are requested.
6.16. Photographic requirements
A photographer is requested for the standard package of digital images for whatever time that they are routinely done. One camera pole is required to mount the miniDV camcorder we will be bringing along on the flights. The camera will be battery powered. Two (2) blank 60 min MiniDV tapes are requested.
Aircraft Loading
We will require a forklift and a lifting pallet to load the equipment into the aircraft.
The test assembly has 4 handles attached for ground crew to manhandle the equipment into position to be bolted onto the aircraft floor beams once it is aboard the aircraft.
The total weight of the main cart assembly to be loaded onto the aircraft is 125.5lb. In addition, the camcorder to be attached to the ( provided ) mounting pole weighs approximately 2 lbs.
The base plate area of the single assembly is 9 ft2 for an average load pressure of
13.9 lb/ft2.
During loading operations, the presence aboard of the 4 required ground crew will increase both the total (temporary) load weight and effective contact floor area to a load stress of approximately 43 lb/ft2.
6.18. Ground Support Requirements
There is no expected need for ground support at Houston. No pressurized gas or power for ground testing research equipment is necessary. Also, no chemicals will be used during this experiment, and we will bring our own tools.
6.19. Hazardous Materials
The only hazardous materials employed are the wooden top shelf, and the other wooded support items which are flammable. There is no exposure of the wooden materials to any ignition sources, save the low current well insulated and circuit wires in their vicinity. The wiring will be contained for the majority of the runs in safety conduit.
Material Safety Data Sheets
Not applicable
Experiment Procedures Documentation
EQUIPMENT SHIPPING
All experimental equipment shall be driven, along with team, from Austin on July 18, 2002. Storage requirements include a minimum space of (L X W X H) 65 X 35 X 55 inches at room temperature (approx. 22( C).
GROUND OPERATIONS
While we will not need ground operation during flight operations. For the test readiness review we will require a 54”x 24” floor space for the experiment with access on all four sides as well as room for extra tools and equipment/chairs and a power outlet or outlets of standard 115 VAC, 60 Hz, 3 Amps. We will also require time to setup our software/electronics system and test the experiment before the Test Readiness Review which may take place outside normal business hours.
We request tools for bolting the aluminum base plate of the test assembly to the floor of the KC-135 as well as two sets of foot straps and two camera poles for use on board the KC-135. Loading of testing equipment cart may require a forklift or several people.
LOADING
From 6.17 Aircraft Laoding:
We will require a forklift and a lifting pallet to load the equipment into the aircraft.
The test assembly has 4 handles attached for ground crew to manhandle the equipment into position to be bolted onto the aircraft floor beams once it is aboard the aircraft.
The total weight of the main cart assembly to be loaded onto the aircraft is 125.5lb. In addition, the camcorder to be attached to the ( provided ) mounting pole weighs approximately 2 lbs.
The base plate area of the single assembly is 9 ft2 for an average load pressure of
13.9 lb/ft2.
During loading operations, the presence aboard of the 4 required ground crew will increase both the total (temporary) load weight and effective contact floor area to a load stress of approximately 43 lb/ft2.
PRE-FLIGHT
Load and secure test cart
Load and secure video camera(s)
Connect electrical power cord to aircraft.
Turn on all electrical power supplies and start software.
Systems test.
Suit up test subjects with ‘un-clipped’/non-compressing harness.
We have no special requirements regarding cabin temperatures, power availability, or in-flight storage space.
TAKE-OFF/LANDING
There are no special procedures for take-off or landing
IN-FLIGHT
Subjects 1 and 2 will be operating the two testing areas of the test equipment cart. Subject 1 will begin testing at the cylinder probe test and computer 2 with a singular software test, while Subject 2 begin testing with computer 1 and 2 software tests (see Experiment Description).
Checklist scenario 1a (first eighth of day’s parabolic flight, subject 1)
Prior to beginning of parabola, subject 1 secures their harness into the ‘secure’ position of compression and then begins the check list of procedures during weightlessness.
___ Secure heart rate monitor
___ Click “Start” on computer program
___ Operate singular software program on Computer 2 until weightlessness ceases
Checklist scenario 1b (first eighth of day’s parabolic flight, subject 2)
Subject 2 keeps their harness in the ‘un-clipped’ position of no-compression and then begins the checklist of procedures during weightlessness.
___ Secure heart rate monitor
___ Click “start” on first software program test on Computer 1
___ Operate first software program test on Computer 1 until weightlessness ceases
Checklist scenario 2a (second eighth of day’s parabolic flight, subject 1
___ Secure heart rate monitor
___ Operate Cylinder Probe test within test parameters until weightlessness ceases
Checklist scenario 2b (second eighth of day’s parabolic flight, subject 2)
___ Secure heart rate monitor
___ Click “start” on second software program test on Computer 1
___ Operate second software program test on Computer 1 until weightlessness ceases
Subject 1 will switch places with subject 2 between parabolas.
Checklist scenario 3a (third eighth of day’s parabolic flight, subject 1)
___ Secure heart rate monitor
___ Click “start” on first software program test on Computer 1
___ Operate first software program test on Computer 1 until weightlessness ceases
Checklist scenario 3b (third eighth of day’s parabolic flight, subject 2)
___ Secure heart rate monitor
___ Click “Start” on computer program
___ Operate singular software program on Computer 2 until weightlessness ceases
Checklist scenario 4a (fourth eighth of day’s parabolic flight, subject 1)
___ Secure heart rate monitor
___ Click “start” on second software program test on Computer 1
___ Operate second software program test on Computer 1 until weightlessness ceases
Checklist scenario 4b (fourth eighth of day’s parabolic flight, subject 2)
___ Secure heart rate monitor
___ Operate Cylinder Probe test within test parameters until weightlessness ceases
Subject 1 now “un-clips” the harness between parabolas so that there is NO compression felt throughout the second half of the flight.
Subject 2 now “clips” the harness between parabolas so that there is full compression felt throughout the second half of the flight.
Checklist scenario 5a & 6a(fifth eighth & sixth eighth of day’s parabolic flight, subject 1)
___ Repeat Checklist scenario 4a & 3a.
Checklist scenario 5b & 6b(fifth eighth & sixth eighth of day’s parabolic flight, subject 2)
___ Repeat Checklist scenario 4b & 3b.
Subject 1 and 2 now switch places between parabolas.
Checklist scenario 7a & 8a (final quarter of day’s parabolic flight, subject 1)
___ Repeat Checklist scenario 1a & 2a
Checklist scenario 7b & 8b (final quarter of day’s parabolic flight, subject 2)
___ Repeat Checklist scenario 1b & 2b
EMERGENCY OPERATIONS FOR THE TERMINATION OF EXPERIMENT
To terminate experiment, subject must simply relieve compression of harness and/or remove harness. If the harness is secured in full compression, use side release clips to “un-clip” harness. Once harness is inflicting NO compression, use the right-handed quick release on the chest to escape the torso of harness. Remove velcro from knee secure, un-clip ankle secure and unzip mid-section of harness before stepping out of harness.
POST-FLIGHT
No special procedures are required.
OFF-LOADING
No special procedures are required
Bibliography
Richard S. Johnston and Lawrence F. Dietlein, Biomedical Results from Skylab, 1977
NASA Ames Research Center: Space Physiology Laboratory; March 2002
G. Harry Stine, 1997; Living in Space: A Handbook for Work and Exploration Stations Beyond the Earth’s Atmosphere. Ch6, p 78-81; C10, p 157
Albert A. Harrison, 2001; Space Faring: The Human Dimension. Ch3, p 44
Brain Res Brain Res Rev 1998 Nov; 28 (1-20): 118-35. “Interaction of vestibular, somatosensory and visual signals for postural control and motion perception under terrestrial and microgravity conditions- a conceptual model.” Abstract. Neurology, University Clinics, Neurozsentrum, Breisacher Str. 64, D-79106, Freiburg, Germany
John R. Ball and Charles H. Evans, Jr., Editors. Safe Passage: Astronaut Care for Exploration Mission
Jennifer Lang, 2000, “Putting the pressure on.”, May 2002
NASM Space Artifacts: Penguin-3 Muscle and Bone Loading Suit, Shannon Lucid, May 2002
Jpn J Physiol 2000 Feb;50(1):41-7, “Histochemical responses of human soleus muscle fibers to long-term bedrest with or without countermeasures..” Ohira Y, Yoshinaga T, Nonaka I, Ohara M, Yoshioka T, Yamashita-Goto K, Izumi R, Yasukawa K, Sekiguchi C, Shenkman BS, Kozzlovskaya IB. Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kanoya, Japan. ohira@nifs-k.ac.jp
Arch Otorhinolaryngol; 244(3):147-54;1987. “Effect of spaceflight on thresholds of perception of angular and linear motion.” Abstract. Royal Air Force of Aviation Medicine, Farnborough, Hants, UK.
-----------------------
[1] Richard S. Johnston and Lawrence F. Dietlein, Biomedical Results from Skylab, 1977
2. NASA Ames Research Center: Space Physiology Laboratory;
[2] G. Harry Stine, 1997; Living in Space: A Handbook for Work and Exploration Stations Beyond the Earth’s Atmosphere.
[3] Albert A. Harrison, Space Faring: The Human Dimension, 2001
[4] Brain Res Brain Res Rev 1998 Nov; 28 (1-20): 118-35. “Interaction of vestibular, somatosensory and visual signals for postural control and motion perception under terrestrial and microgravity conditions- a conceptual model.” Abstract. Neurology, University Clinics, Neurozsentrum, Breisacher Str. 64, D-79106, Freiburg, Germany
[5] John R. Ball and Charles H. Evans, Jr., Editors. Safe Passage: Astronaut Care for Exploration Mission
[6] Jennifer Lang, 2000, Putting the pressure on,
[7] NASM Space Artifacts: Penguin-3 Muscle and Bone Loading Suit, Shannon Lucid,
[8] Jpn J Physiol 2000 Feb;50(1):41-7, “Histochemical responses of human soleus muscle fibers to long-term bedrest with or without countermeasures..” Ohira Y, Yoshinaga T, Nonaka I, Ohara M, Yoshioka T, Yamashita-Goto K, Izumi R, Yasukawa K, Sekiguchi C, Shenkman BS, Kozzlovskaya IB. Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kanoya, Japan. ohira@nifs-k.ac.jp
[9] Arch Otorhinolaryngol; 244(3):147-54;1987. “Effect of spaceflight on thresholds of perception of angular and linear motion.” Abstract. Royal Air Force of Aviation Medicine, Farnborough, Hants, UK.
[10] G. Harry Stine, Living In Space: A Handbook for Work and Exploration Stations Beyond the Earth’s Atmosphere, 1997
[11] NASA Ames Research Center: Space Physiology Laboratory;
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Andrea Pearlman with un-clipped harness.
Figure b: Back view
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