4. SPACE TECHNOLOGY PROJECTS.
Skylab provides a unique opportunity to develop a better understanding of the effects of the space environment on materials and operational devices. Skylab can also be used as a platform to measure the environment within and outside of a spacecraft, and man's influence upon this environment. A number of Skylab experiments will provide data about engineering and technological operations in the space environment; these data will be important in the development of future Earth orbital space stations and spacecraft. Thus, through the Skylab program, it will be possible to learn more about how man performs in space, what tools he needs to accomplish his tasks, what his influence is on the space environment, and how materials can be processed in space.
The space technology experiments on Skylab can be divided into the following categories; they Will be grouped in this order in the descriptions that follow.
a. Astronaut Tools and Equipment
In addition to specific experiments, there is a considerable array of tools, miscellaneous supplies, and support equipment for the crewmen in the Skylab (Fig. 193), including tool kits, repair kits, restraints, supplies, a film vault, photographic equipment, and TV cameras. Two tool kits are installed and retained in standard stowage lockers. The tools provided include standard ranges and sizes of sockets, open end/box wrenches, screwdrivers, and  screwdriver bits. Also included are a vise, a speeder handle, a spin-type handle, a ratchet handle, a pin straightener, and other common handtools.
A repair kit is also installed in a standard stowage locker. This kit contains the necessary types and sizes of blister patches to repair structural leaks. Additional items provided include flat patches, Teflon tape, sealant putty, Velcro fasteners, restraints, scissors, and tape for repairing air duct damage.
Another support kit includes tension and compression scales, a steel measuring tape, a sound level meter, a frequency analyzer, two surface temperature digital thermometers, three ambient thermometers, and an air velocity measuring instrument
Cameras using both film and television are provided. To support the film cameras, there is a film vault to provide protection from radiation (Fig.194). Photographic lights, power and signal cables, versatile mobile restraints, and convenience outlets are provided. The film cameras available for use inside the Skylab include a 16 mm Data Acquisition Camera (frame rates 2, 4, 6, 12 and 24 frames per second with shutter speeds from 1/60 to 1/1,000 of a second), 35 mm, and 70 mm still cameras. Speed, resolution, and coverage depend upon film and lens selected.
b. Materials Science and Manufacturing in Space
The zero-gravity condition existing in Skylab makes it possible to perform operations in materials processing that would be impossible or extremely difficult on Earth. Melting and mixing without the contaminating effects of containers, the suppression of convection and buoyance in liquids and molten....
....material, control of voids, and the ability to use electrostatic and magnetic forces otherwise masked by gravitation open the way to new knowledge of material properties and processes and ultimately to the production of valuable new materials for use on Earth. These potential products range from composite structural materials with specialized physical properties to large and highly perfect crystals with valuable electrical and optical properties. In addition, it will be possible to evaluate the feasibility of using electron beam and thermo-welding under zero-gravity conditions.
Practical experience with principles and problems of development and integration which has been gained in developing the Skylab materials processing facility has already proved very valuable in the concept planning of an improved and enlarged facility for incorporation into the Space Shuttle Program. Final facility design for Shuttle missions will be based upon the evaluation of the Skylab program results, and after detailed user requirements have been specified.
M479, Zero-Gravity Flammability
Objective and Instrumentation:
Obtain photographic data of various combustible materials ignited under controlled conditions in a zero-gravity environment to determine the extent of flame propagation and flashover to adjacent materials, rates  of surface and bulk flame propagation under zero-convection, self-extinguishment characteristics, and extinguishment characteristics by vacuum or water spray. The combustion chamber and controls for this experiment are provided by Experiment M512 (Fig. 195). The combustion chamber is stainless steel with a low emissivity interior (Fig. 196). A large opening on one end permits installation of igniter-fuel assemblies. Chamber connections are provided for venting either to the vacuum of space to exhaust smoke and products of combustion, or venting to the vehicle interior to equalize pressure and to permit opening. Interior work lights are provided as well as means to remove solid ash particles by a vacuum cleaner equipped with a filter trap. Provisions are also made to spray water to evaluate extinguishment by that means. The igniter-fuel assemblies are housed in a separate container which serves both as a protection to the assemblies and as a place to dispose of used assemblies after testing. Data will be recorded on motion picture film to be returned to Earth for analysis. The astronaut will provide voice comments while performing the experiment.
 M512, Materials Processing Facility (Fig. 197)
Objective and instrumentation:
Perform fundamental research on the effects of zero-gravity on molten metal processing. All the tasks belonging to this experiment involve the melting of materials by the application of heat. On Earth, the density differences caused by temperature differences result, under the influence of gravity, in convection. For many purposes, this is a hindrance on Earth; however, in zero gravity there will be no convection due to temperature differences.
 Another effect of gravity that will be avoided in space processing is the separation of different density materials in the preparation of composites. Certain materials of superior characteristics could be produced if a uniform or other preferred mixture of substances of different densities could be attained. On Earth, fibers or particles embedded in a melt will either float or settle if their density differs from that of the matrix, but in space this will not occur.
The place where materials processing and a number of other experiments on manufacturing in space will be carried out is the M512 facility. This facility, mounted in the MDA, consists of a vacuum work chamber with associated mechanical and electrical controls, an electron beam subsystem (Fig. 198), and a control and display panel. The vacuum chamber is a 40 cm (16-in) sphere with a hinged hatch for access. It is connected to the space environment by a 10-cm (4 in) diameter line containing two gate valves. The electron beam subsystem is mounted to the chamber so that the beam traverses the sphere along a diameter parallel to the plane of the hatch closure. The chamber wall contains a cylindrical well accommodating the small electric furnaces used for the M555 experiment. A receptacle above the well provides power and instrumentation lead connections to the control panel. Auxiliary provisions include ports for a floodlight and the 16 mm data acquisition camera, a bleed line, a repressurization line, and a port for a vacuum cleaner to remove debris from the chamber. A subsystem is also provided for spraying water into the chamber during some runs of the M479 experiment.
The electron beam operates nominally at 20 kilovolts and 80 milliamperes. Focusing and deflection coils can be operated from the control panel to adjust the size and position of the beam impingement spot on the experiment samples.
The control panel contains controls and displays for all experiments to be performed in the facility, including a pressure gauge for the vacuum chamber, voltage and current meters for the electron beam, and a thermocouple temperature indicator.
 Functions of the crew will include installing specialized apparatus and samples for each experiment in the chamber, operation of the experiments from the control panel, observation of some experiments through a viewport in the chamber hatch, data recording, and disassembly of each experiment after it is performed.
The control panel of the M512 facility permits switch settings and dial readings (Fig. 197). All data taken from the control panel must be recorded in writing or on voice recorder tape by the crew.
Data from the experiments will comprise the samples, those parts of the apparatus that are to be returned, motion picture records of the two electron beam experiments and M479, and comments by the operating crewmen. The returned samples will be studied in comparison with control samples produced on Earth.
Four tasks are contained in this experiment:
M551, Metals Melting - Examine the molten metal flow characteristics of various metal alloys. Metal samples will be melted by electron beam and photographed. Specimens will be analyzed after return. Principal Investigator: R. M. Poorman, Marshall Space Flight Center, Huntsville, Alabama.
M552, Exothermic Brazing - Develop a stainless steel tube joining technique for assembly and repair in space; evaluate the flow and capillary action of molten braze material, using exothermic material as heat source; and demonstrate the feasibility of exothermic reaction brazing in space. Principal investigator: J. Williams, Marshall Space Flight Center, Huntsville, Alabama.
M553, Sphere Forming (Fig. 198) - Produce spherical shapes of about 6 mm (.236 in) diameter from molten specimens of metals under the forces of surface tension by taking advantage of the virtual absence of gravity. Spheres will be evaluated on Earth. Principal Investigator: E. A. Hasemeyer, Marshall Space Flight Center, Huntsville, Alabama.
M555, GaAs Crystal Growth - Grow single crystals of gallium arsenide of exceptionally high chemical purity and crystalline perfection. GaAs will dissolve in liquid gallium metal at the hot end (750° C or 1382° F) of a quartz tube; crystals will form on seed crystals at the cold end (550° C or 1022° F) of the tube. The tube will be opened for crystal analysis after return to Earth. Principal Investigator: Dr. M. Rubenstein, Westinghouse Electric Corporation, Pittsburgh, Pennsylvania.
M518, Multipurpose Electric Furnace System (Fig. 199)
Objective and instrumentation:
Provide a means for experimentation in solidification, crystal growth, composite structures, alloy structural characteristics, and other thermal proc-...
...-esses involving changes in materials under conditions of weightlessness. The system consists of three main units, the Multipurpose Furnace, the Control Package, and 33 cartridges (11 experiment sets). The Furnace has three specimen cavities so that three material samples (cartridges) can be processed in a single run. The furnace is designed to provide three different temperature zones along the length of each sample cavity, as follows:
(1) A constant temperature hot zone at the end of the sample cavity where temperatures up to 1000° C (1832° F) can be reached,
(2) A gradient zone next to the hot zone where temperature gradients ranging from 20° C (36° F) per centimeter to 200° C (360° F) per centimeter can be established in the samples, and
(3) A cool zone in which heat conducted along the samples will be radiated to a conducting path that carries the heat out of the system.
The control package, providing active control of the furnace temperature, can be set to any specified temperature within the furnace's capability (0° to 1000°C or 32°F to 1832°F) by the astronaut operating the system. Two timing circuits in the controller will enable the astronaut to program the soak time spent at the set temperature and the cooling rate of the furnace following the end of the soak period. The cartridge encapsulates the sample material, and the actual temperature distribution applied to the sample will be controlled by the thermal design of the cartridge. Once the specimens are installed in the furnace and the system is activated, the Multipurpose Electric Furnace System will operate automatically except for complete system shutdown.
The eleven experiments planned for the M518 system and their objectives are:
M556 Vapor Growth of II-VI Compounds1 - Determine the degree  of improvement that can be obtained in the perfection and chemical homogeneity of crystals grown by vapor transport under weightless conditions Principal Investigator: Dr. H. Wiedemeier, Rensselaer Polytechnic Institute, Troy, New York.
M557-Immiscible Alloy Compositions - Determine the effects of near zero-gravity on the processing of material compositions which segregate in the melt on Earth because of density differences. Principal Investigator: J. Reger, Thompson Ramo Wooldridge, Redondo Beach, California.
M558 Radioactive Tracer Diffusion - Measure self-diffusion and impurity diffusion effects in liquid metal under zero gravity, and characterize the disturbing effects, if any, as a consequence of spacecraft acceleration. Principal Investigator: Dr. T. Ukanwa, NASA-Marshall Space Flight Center, Huntsville, Alabama.
M559-Microsegregation in Germanium - Determine the degree of microsegregation of doping impurities in germanium caused by convectionless directional solidification under conditions of weightlessness. Principal Investigator: Dr. F. Padovani, Texas Instruments, Dallas, Texas.
M560 Growth of Spherical Crystals - Grow doped germanium crystals of high chemical homogeneity and structural perfection, and compare their physical properties with theoretical values for ideal crystals. Principal Investigator: Dr. H. Walter, University of Alabama in Huntsville, Huntsville, Alabama.
M561-Whisker-Reinforced Composites - Produce void-free samples of silver and aluminum reinforced with oriented silicon carbide whiskers. Principal Investigator: Dr. T. Kawada, National Research Institute for Metals, Tokyo, Japan.
M562-Indium Antimonide Crystals - Produce doped semiconductor crystals of high chemical homogeneity and structural perfection, and evaluate the influence of weightlessness in attaining these properties. Principal Investigator: Dr. H. Gatos, Massachusetts Institute of Technology, Cambridge, Massachusetts.
M563-Mixed III-V Crystal Growth 2 - Determine how weightlessness affects directionality of binary semiconductor alloys.
If single crystals are obtained, determine how their semiconducting properties depend on alloy composition. Principal Investigator: Dr. W. Wilcox, University of Southern California, Los Angeles, California.
M564-Halide Eutectics - Produce samples of the fiberlike sodium chloride-sodium fluoride eutectic, and measure its physical properties. In particular, optical parameters of the space-produced material will be of interest. Principal Investigator: Dr. A. Yue, University of California at Los Angeles, Los Angeles, California.
M565 Silver Grids Melted in Space - Determine how pore sizes and pore shapes change in grids of fine silver wires when they are melted and resolidified in space. Principal Investigator: Dr. A. Deruythere, Catholic University of Leuven, Heverlee, Belgium.
 M566 Copper-Aluminum Eutectic - Determine the effects of weightlessness on the formation of lamellar structures in eutectic alloys when directionally solidified. Principal investigator: E. Hasemeyer, NASA. Marshall Space Flight Center, Huntsville, Alabama.
c. Zero-Gravity Systems Studies
The zero-gravity systems studies experiments were selected to gain engineering data on man's capabilities in the weightless environment and to evaluate instruments and systems designed to increase the crew's ability to move and work in such an environment. These investigations support the broad Skylab program objectives of developing and advancing man's capability to live and perform useful work in space. Evaluations will be made of the crew's ability to perform zero-gravity tasks requiring both gross and delicate manipulations. A series of measurements will be taken to determine the effects of mission duration and prolonged weightlessness on the crew's ability to repeat these same tasks in a skillful and timely manner. Accurate measurements will be made of vehicle disturbances caused by crew activities. These results are essential for the definition of allowable crew motions during the conduct of experiments requiring low levels of acceleration (10-4 to 10-5 g) or pointing with extreme accuracy and for the design of attitude control systems for future space missions. Other experiments will evaluate operating concepts for astronaut maneuvering devices. The data obtained will be applied to future programs for extra-vehicular activities such as assembling large space structures, inspection and maintenance, repair, refurbishment, rescue, and data retrieval. Several astronaut maneuvering units and labor saving aids will be evaluated during the mission.
M487, Habitability/Crew Quarters
Objective and Instrumentation:
Evaluate the features of Skylab's living quarters, crew provisions, and support facilities as they affect the crew's comfort, safety, and operating efficiency. Equipment, procedures, and habitat design concepts derived from experience on Earth and from previous short-duration orbital flights, may require modification. This evaluation is a multidisciplinary set of systematic observations, and it serves as a test and validation of design concepts and technical features. The following aspects of system design and operation will be studied: physical environment (temperature, humidity, light, noise); architecture (volume and layout of working and living areas); mobility aids and personal restraints (translation, worksite support, sleep stations); food and water (storage, preparation, quality); personal garments (comfort, durability, design); personal hygiene (cleansing, grooming, collection and disposal of body waste); housekeeping (habitat  cleansing, waste control and disposal); off-duty activities (exercise facilities, individual and group recreation, privacy features); and communications.
Instruments used in this study include a portable surface temperature digital thermometer, sound level meter, frequency analyzer, air velocity meter, measuring tape, and ambient thermometers. Motion picture cameras, lights, and tape recorders will be available from other experiments. Data will be recorded in the form of motion picture films and voice tape comments The data will be evaluated on Earth after they are returned.
M509, Astronaut Maneuvering Equipment (Fig. 200)
Objectives and Instrumentation:
Conduct an in-orbit verification of the utility of various maneuvering techniques to assist astronauts in performing tasks which are representative of future extravehicular activity (EVA) requirements.
The concept of powered astronaut maneuvering is fundamental to the development of an effective EVA capability which, in turn, is considered....
 ....to be a routine supporting element in future manned space flight. EVA is expected to play a major role in such areas as space rescue, inspection and repair of parent and satellite spacecraft, personnel and cargo transport, and space structure erection. The addition of maneuvering aids to such EVA tasks is expected to reduce crew fatigue and stress, cut time requirements, offset pressure suit mobility limitations, and facilitate attitude orientation and stabilization.
The astronaut maneuvering equipment of Experiment M509 consists of two jet-powered aids for maneuvering in a zero-gravity space environment. The first is a back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU); the second a Hand-Held Maneuvering Unit (HHMU). A backpack, serving both units, contains a rechargeable or replaceable high pressure nitrogen propellant tank. It will be worn for the ASMU and for the HHMU (Fig. 201). The electrical systems within the backpack are powered by a rechargeable or replaceable battery. The astronaut dons the backpack over either a pressurized space suit or flight coveralls, using a quick release harness similar to that used for parachutes.
The Automatically Stabilized Maneuvering Unit is maneuvered in six degrees of freedom (X, Y, and Z axis translation, and pitch, yaw, and roll) by means of 14 fixed thrusters located in various positions on the backpack. Control of the thrusters is achieved by two hand-controllers mounted on arms extending from the backpack. The controllers are identical to....
 ....those used in the Apollo spacecraft. The Hand-Held Maneuvering Unit is a simple, small, lightweight, completely manual device similar to the one used in Gemini. It consists of a hand grip and controls for a pair of tractor (pull) thrusters and an opposing single pusher thruster; the assembly is connected to the ASMU propellant tank by a short hose. To orient and propel himself in any attitude or direction, the operator points the HHMU, aligns it so that the thrust vector passes approximately through his center of gravity, and triggers the tractor or pusher thrusters as indicated by his visual cues. Maneuvering with the ASMU and the HHMU on Skylab will be performed within the Orbital Workshop.
The ASMU is instrumented to record numerous engineering and biomedical data during the pressure-suited runs. These data will be sensed, collected, and telemetered from the free-flying ASMU to a receiver within the Orbital Workshop. Together with recorded voice commentary, the data will be telemetered from the OWS to ground stations. Additional experiment data will be provided by inflight television, postflight still and motion picture data, and logbook entries. It is expected that M509 will provide a wide range of valuable information on maneuvering unit handling qualities, operating techniques, consumable requirements, capabilities, and limitations.
M516, Crew Activities and Maintenance Study
To investigate crew performance in zero gravity, long-duration missions, primarily through observations of normal Skylab tasks. This experiment is oriented toward the design of future space equipment and work provisions rather than basic human performance. The experiment calls for systematic documentation of man's performance during prolonged weightless space flight, acquisition and evaluation of inflight maintenance data, and evaluation of data relative to design criteria for future manned missions, There is no requirement for any special equipment solely for this experiment. Data will be acquired for normal Skylab inflight activities. They will be recorded by film, voice tapes, logbook entries, TV transmissions, and telemetry.
T002, Manual Navigation Sightings (Fig. 202)
Objective and Instrumentation:
Investigate the effects of the space flight environment (including long-mission time) on the navigator's ability to take space navigation measurements....
.....through a spacecraft window using hand-held instruments. Previous data obtained with the use of simulators, aircraft, and the Gemini spacecraft have already demonstrated that man, in a space environment, can make accurate navigation measurements using simple hand-held instruments. The intent of this experiment is to determine whether long-mission duration appreciably affects the capability of man to obtain accurate measurements. Further, the experiment will return data which will be generally indicative of the effect of long-duration space flight on man's capability to perform other precision tasks. The instrumentation for this experiment consists of a sextant and a stadimeter, both hand-held. The sextant, similar to an aviator's sextant, will be used to measure the; angles between two stars and between single stars and the edge of the Moon. The stadimeter, also an optical device, determines spacecraft altitude directly by measuring the apparent difference in elevation angle between a portion of the Earth's horizon and its subtended chord. Data return will be in the form of logbook entries of the sextant and stadimeter readings. This will be supplemented by crew comments on the voice tape recorder.
T013, Crew/Vehicle Disturbance
Objective and instrumentation:
Determine the effect of the crew's activities within the spacecraft on the Skylab vehicle's pointing stability. Many Earth-pointing and astronomy experiments in future manned space programs will require pointing  accuracies of fractions of a second of arc. One of the most significant hindrances to achieving this accuracy will probably be the movement of the astronauts operating the spacecraft. Adequate design of the pointing control system for these future vehicles demands accurate knowledge of these effects. In this experiment, the forces exerted on the spacecraft by specific astronaut body and limb movements will be precisely measured. A limb motion sensor, attached to a suit, will measure the relative motions of the body, upper arm, lower arm, and upper and lower leg. The astronaut performing the experiment will be attached to a device that measures the force exerted on the Skylab structure by his activities. The limb movements and forces will be recorded on tape, and the activity will be photographed on motion picture film.
T020, Foot-Controlled Maneuvering Unit (Fig. 203)
Objective and instrumentation:
Evaluate an astronaut maneuvering device that does not require use of the astronaut's hands. The Foot-Controlled Maneuvering Unit (FCMU) is a research apparatus for examining the maneuvering dynamics of a cold gas jet-powered personal propulsion system in a zero-gravity space environment. The FCMU is propelled by high pressure nitrogen supplied from the M509 back-mounted tank. The operator, wearing either a pressurized space suit or flight coveralls, will control pitch, yaw, roll, and translation along his head-foot axis through a combination of toe and foot commands. Both the FCMU propellant tank and battery are rechargeable or replaceable units; they are shared with the astronaut maneuvering equipment of Experiment M509. Most of the data collection will be accomplished by two motion picture cameras, one mounted in the workshop dome and a battery-powered, forward-looking camera mounted within the FCMU frame. Additional data will be supplied by recorded voice commentary and logbook entries. It is expected that the information derived from this experiment will add valuable engineering inputs into future maneuvering unit design.
d. Spacecraft Environment
The Spacecraft Environment experiments on Skylab are concerned with measuring the radiation in the spacecraft, contamination around the spacecraft, and the effects of the spacecraft environment on thermal control coatings
The major source of radiation encountered by a spacecraft in Earth orbit is the South Atlantic Anomaly, a region where the Van Allen radiation belts are unusually close to Earth because of the unsymmetrical shape of the Earth's magnetic field. In addition, however, major solar flares can generate high energy protons and alpha particles. Also, there is continuous background radiation from cosmic ray sources. Measurements of the radiation....
....environment are needed to better predict the radiation dose received by man in Earth orbit.
Thermal control coatings with selected absorption and emission properties are applied to spacecraft surfaces to aid in maintaining the desired temperatures inside the spacecraft. Unfortunately, the environments to which these coatings are exposed before and during flight often alter their properties in a sense of making them less effective. Two Skylab experiments are designed to measure the effects of the space environment upon thermal control coatings.
Clouds of particles surrounding a spacecraft are termed contamination; this contamination may lead to deposits on optical surfaces, and it also may degrade visibility around the spacecraft. Particles originate from thruster firings, water and urine dumps, and outgassing of spacecraft surfaces. Two Skylab experiments will measure the contamination environment around Skylab.
 D008, Radiation in Spacecraft (Fig. 204)
Objective and instrumentation:
Make radiation dose measurements in Earth orbit. These measurements are of value in assessing the quality of dosimetry instrumentation for use in space, in evaluating analytical procedures for predicting radiation doses in Earth orbit, and in studying the biological reaction of man to radiation. Instrumentation for this experiment consists of one portable tissue-equivalent dosimeter, one Linear Energy Transfer system comprised of two solid-state particle detectors which measure equivalent ranges in tissue of incident particles, and five passive dosimeters. The passive dosimeters and the Linear Energy Transfer system are placed in specific locations and remain there throughout the Skylab mission. The tissue-equivalent dosimeter will be moved to various locations in the spacecraft during measurement periods. Data from the tissue-equivalent dosimeter and the Linear Energy Transfer system will be telemetered to Earth; in addition, the logbook of events during measurement periods and the passive dosimeters will be returned to Earth for analysis.
 D024, Thermal Control Coatings (Fig. 205)
Objective and Instrumentation:
Expose samples of thermal control coating materials to the space environment in order to compare results with ground-based simulations, and to determine mechanisms of degradation due to the space environment and space radiation. This experiment measures degradation that occurs only while the Skylab is in or near Earth orbit; Experiment M415 measures...
 ....launch and pre-launch effects. The instrumentation consists of two panels, each containing 36 thermal control coating samples (Discs of 2.5 cm or 1 inch diameter). The panels will be protected by covers and will be exposed only to the space environment. One panel will be retrieved and placed in a hermetically sealed container and then returned to Earth for analysis of the first manned mission; the other will be returned to Earth on the second manned mission.
M415, Thermal Control Coatings (Fig. 206)
Objective and instrumentation:
Determine the degradation effects of prelaunch, launch, and space environments on the thermal absorption and emission characteristics of various coatings commonly used for passive thermal control. The principal elements of this experiment consist of two panels, each containing 12 thermal sensors arranged in four sets of three, mounted on the exterior of the Saturn IB launch vehicle. Three different thermal control coating samples are mounted on the sensors in each set. One set of sample coatings will be exposed to all enviromments. A second set will be exposed immediately prior to Launch Escape System Tower jettison and to all environmental conditions thereafter. The third set will be exposed to retrorocket firing and space environments, while the fourth set will be exposed to space environment only. Average thermal-radiative properties can be calculated from telemetered temperature measurements. These calculated values will then indicate how the various environments altered....
 ....coating characteristics. Unlike Experiment D024, detailed spectral reflection measurements cannot be made in this experiment since the coatings will not be retrieved.
T003, Inflight Aerosol Analysis (Fig. 207)
Objectives and Instrumentation:
Measure the size, concentration, and composition of the minute particles present in the atmosphere inside Skylab. The information obtained will be used not only as a measure of the atmospheric quality in Skylab but as a data source in analysis of other Skylab phenomena. Sources of astronaut discomfort, either respiratory or skin, may be related to aerosol buildup; system performance anomalies may be resolved using these aerosol experiment data; also, the data can be used in the design of future spacecraft and equipment. The experiment is self-contained in a box approximately 15 cm x 25 cm x 33 cm (6 in. x 10 in x 13 in.) with an air inlet, an air outlet, a filter selector knob, a channel indicator, and a particle-count readout register (Fig. 207). The channel indicator reads "1", "2", or "3", and the register gives the corresponding concentration of particles in the 1.0 to 3.0 micrometer, 3.0 to 9.0 micrometer, and 9.0 to 100 micrometer ranges. The different settings of the filter are for the different locations where measurements are made. The filter is used to bring particles back for later identification and position correlation. Particle size and count are determined by passing a known volume of...
 ...air through the measuring chamber and measuring the amount of light each particle scatters to a photodetector, and also the number of light pulses which corresponds to the number of particles. Measurements at a main location will be taken three times a day. Every ten days, measurements are made at several other predetermined stations. Ten more measurements can be made anywhere at any time at the crew's discretion The filters used in each measurement will be returned to Earth for analysis.
T025, Coronagraph Contamination Measurements (Fig. 208)
- Dr. Mayo Greenberg
- Dudley Observatory
- Albany, New York
Objectives and instrumentation:
Observe visually and photographically and interpret the particulate atmosphere surrounding the Skylab in orbit; study the change (size, quantity, distribution) in these particles caused by thruster firing and water dumps; and photograph the solar corona to find out if the contamination degrades the ability to see. A disc assembly, mounted on a boom, is extended through the Solar Scientific Airlock. A camera is mounted on the T025 canister so it remains inside the OWS. The disc assembly occults the solar disc from the camera lens so the corona may be photo...
 ....graphed. Of essential interest is the amount of background "fog" produced by stray light falling on the film during exposure. Film will be returned to Earth for analysis.
T027, ATM Contamination Measurements (Fig. 209)
Objective and instrumentation:
Determine the change in optical properties of various surfaces caused by contaminants near the spacecraft by postflight analysis, measure the amount of contaminants deposited on a test surface during flight, and observe the sky brightness caused by solar illumination of contaminants. A sample array system containing 200 samples of 16 different materials (windows, mirrors, gratings, other optical surfaces) and two quartz crystal microbalances will be exposed to the space environment for various durations during a period of five days. The quartz crystal microbalances will measure contaminant masses deposited on their surfaces in near real time. A photoelectric polarimeter photometer, used jointly for Experiments S073 and T027, will measure the brightness of contaminants illuminated by the Sun at elongations longer than 15° from the Sun. A 16 mm camera will be used to record the photometric and polarimetric data on film. At the end of the mission, the individual samples on the sample array will be covered, and the sample array will be placed in a vacuum container for return to Earth for postflight analysis.
 5. SKYLAB STUDENT PROJECT
Through the Skylab Student Project nigh school students of the United States were given the opportunity to participate in the Skylab scientific program. All students in the ninth through the twelfth grades in all United States public, private, parochial, and overseas schools were eligible The Project's purpose is to stimulate interest in science and technology by directly involving secondary school students in a space research program
In October 1971, the National Science Teachers Association, under the auspices of NASA, distributed announcements of the science opportunity and of the method of participating in the Skylab Program. As a result, over 3,400 proposals for experiments were received. The National Science Teachers Association then selected 2.5 proposals as the national winners, announcing their names in April, 1972. The 25 national finalists from 16 states took part in a week of preliminary design review at the George C. Marshall Space Flight Center where they, their parents, and their teacher/sponsors were joined by Skylab scientists, engineers, technicians, and project officials.
After a detailed review by NASA, 19 out of the 25 experiments selected as national winners were approved for Skylab. The NASA review determined that, because of Skylab performance requirements and schedule restrictions, the other six experiments could not be accommodated. This experiment evaluation and flight selection process involved NASA Skylab personnel from the Marshall Space Flight Center, the Johnson Space Center, and the Kennedy Space Center. The 19 students whose experiments were selected for research participated closely in the development of necessary experiment instrumentation and in the detailed planning of their investigations including data retrieval and processing, flight planning, and crew training. After the mission, the students will evaluate their data and report on their experiments. These student experiments, which are handled by Skylab project management in a manner very similar to the handling of main Skylab experiments, reflect remarkable technical abilities. The names of the student experimenters, description of their experiments, and the experiment numbers follow:
This experiment is to derive information on the loss of heat energy in the Earth's atmosphere. It will utilize data from the Earth Resources Experiment Package, Experiment S191, and related ground-truth measurements to be made simultaneously at the Earth's surface.
The purpose of this study is to analyze infrared surveys taken in the areas of known volcanoes by sensors of the Skylab Earth Resources Experiment  Package (Experiments S190A, S190B, S191, S192). The data will be compared with ground-based data to determine whether remote sensing can detect increased thermal radiation which may precede an imminent volcanic eruption
The Skylab solar telescope cameras of the coronagraph experiment S052 will provide pictures of two regions in the Moon's orbit. At two points in tire orbit of the Moon, ahead of and following the Moon in its path, a condition of gravitational equilibrium exists which causes the accumulation of space particles. When each of these regions comes within sight of the Skylab solar telescopes, pictures will be taken, and the brightness and polarization of the reflected light will be measured by Experiments T027 and S073
This observation will attempt to identify a planetary body which may orbit the Sun at a distance approximately 0.1 of the distance from the Sun to the Earth (Mercury's orbital radius is about one-third of the radius of Earth's orbit). The experiment is to be performed by examining about 30,000 Skylab solar telescope photographs taken by the coronagraph of ATM Experiment S052.
Selected photographs obtained by the ultraviolet stellar astronomy equipment (S019) will be analyzed. Photographs of target areas in which quasars have been identified will be studied to obtain spectral data in the ultraviolet region to add to existing data in the radio and visible ranges.
The primary aim is to make observations of celestial regions in X-ray wavelengths in an attempt to relate X-ray emissions to stars and to their spectral characteristics. In addition, observations of the Sun in X-ray and other spectral regions will be studied to re-examine the Sun and its relation to stars in other stellar classes. Pictures from ATM Experiments S054 and S056 will be evaluated.
The purpose of this study is to detect X-rays emitted from Jupiter. The X-ray emission, if detected by Skylab, will be correlated with solar activity and Jupiter's radio emission to derive more information on the radiation- emitting mechanisms of this planet. Pictures taken by the ATM Experiment S054 will be used.
Ultraviolet observations of selected celestial regions will be used in an attempt to relate ultraviolet emissions with known radio-emitting pulsars, and with the pulsar in the Crab Nebula which is known to emit pulses in X-ray, visible light, and radio frequencies. Pictures taken by instrument S019 in the Stellar Astronomy Program will be evaluated.
In this experiment, colonies of various species of bacteria will be studied in the Skylab zero-gravity environment to determine if this environment induces variations m survival rate, growth, and mutations of bacteria and spores different from those observed m identical colonies on Earth.
This experiment seeks to determine if the actions of antibodies are influenced by absence of gravity. An antibody is a substance which acts to destroy specific foreign substances (antigens) such as toxins, bacteria, and dust. Microscope slides used in the experiments are "fixed" by adding acetic acid to stop antibody activity resulting from the introduction of antigens. These slides are then photographed by the astronaut; the photographs are returned to Earth for analysis by the students.
This experiment uses a standard eye-hand coordination test apparatus to measure changes in motor sensory skill of crew members. An astronaut  has to make electric contacts with a hand-held stylus through a pattern of holes in a punch-board-like plate. Total time need for this procedure is a measure of coordination efficiency. Results will be recorded on tape.
Photographic observations will be made of the web building process and the detailed structure of the web of the common cross spider (araneus diadematus) in an Earth environment and in the weightless Skylab environment. Analysis of experiment results will be similar to that of like experiments, without the Skylab environment, performed by the Research Division, North Carolina Department of Mental Health.
These two experiments have been combined into a single joint experiment whose objectives are:
1. To determine the differences between rice seedlings grown in zerogravity, and rice seedlings grown on Earth under similar conditions, with respect to root and stem growth, and orientation.
2. To determine whether light can be used as a substitute for gravity in causing the roots and stems of rice seedlings to grow in a desired direction under zero-gravity, and if so, to determine the minimum light level required.
Photographic records of the experiment will be returned to Earth.
Microscopic observation will be performed by an astronaut on leaf cells of elodea plants 3 in zero gravity to determine if there is a difference between the motion of intracellular cytoplasm under weightlessness and intercellular cytoplasmic motion in similar leaf cells on Earth. Cytoplasm is the protoplasm of a cell exclusive of the nucleus.
The purpose of this experiment is to determine if the zero-gravity environment induces changes in the characteristics of capillary and wicking action from the familiar Earth-gravity characteristics. The motion of liquids through capillary tubes will be recorded photographically.
This experiment complements the existing Skylab specimen mass and body mass measurement devices. The equipment consists of a simple leaf spring anchored at one end and with the mass to be measured at the other end. The experiment operates on the same principle as the biomedical Skylab mass measurement devices.
Detectors inside Skylab will record neutrons from three potential sources; Earth albedo neutrons, high energy neutrons from the Sun, and neutrons from secondary processes on Skylab. The detectors mounted on the inboard faces of the Skylab water tanks will record neutrons which have been moderated during their passage through the water in the tanks, and then produce fission particles which generate ionization tracks in a plastic material. Detectors mounted elsewhere in the Skylab will furnish control data. Chemical treatment of the plastic after return to Earth will reveal readily identifiable tracks.
This experiment will observe the motion of a gas bubble surrounded by a fluid when excited by a known driving force. Provisions will be made for varying the size of the bubble.
6. POSTFLIGHT DATA EVALUATION
Responsibility for the reduction and evaluation of Skylab experiment data lies primarily with the Principal investigators. Telemetry data will be made available to investigators through the Mission Control Center at JSC as quickly as possible after receipt of the data. Films, tapes, samples, logbooks, and other data records to be brought back in the returning Command Modules will be taken to the Mission Control Center by the recovery team and then distributed to Principal investigators. Additional data, such as spacecraft positional location, details of Skylab performance, trajectory information, Skylab attitude as a function of time and location, environmental data, records of radiation and contamination sensors, and other data of specific interest to investigators will be furnished by the Lyndon B. Johnson Space Center in Houston or the George C. Marshall Space Flight Center in Huntsville.
Most of the experiments will be performed on all three manned missions. A preliminary "quick look" evaluation of experimental results after the first and the second mission will be of great importance in these experiments, because results of one mission may determine whether an experiment should be modified for the following missions.
For some groups of experiments, one of the NASA Centers bears a broad overall responsibility; for example, the Lyndon B. Johnson Space Center is responsible for the Earth Resources Experiment Package (EREP), while a number of Principal investigators are individually responsible for the experiments within this package. Data evaluation plans for EREP include the following activities:
1. By JSC (within two weeks after CM Recovery):
- Films will be developed.
- Films and tapes will be duplicated.
-  Strip charts, tabulations, and pictures will be made from tapes.
- Logs and voice recordings will be transcribed.
- Supporting data on Skylab performance will be documented.
- Films and other records will be furnished to Principal investigators.
- Teams will make "quick look" evaluation.
- Preliminary results will be furnished to Science Analysis Teams, Mission Planning, and NASA Public Affairs Offices.
2. By the Principal Investigators:
a. Within four weeks after CM recovery:
- Detailed screening of data.
- Careful correlation of data with sensor performance and Skylab operational data.
- Data analysis and evaluation.
- Feedback made to NASA Mission Planning.
- Preliminary Science Reports written.
b. During the first year after CM recovery:
- Thorough analysis of data.
- Data packages prepared for user agencies.
- Final Science Reports prepared.
- Suggestions made for future projects.
c. After about one year:
Original data will be made available to any qualified investigator. Data evaluation plans for the various groups of Skylab experiments differ in some details; for example, ATM films will be developed by the Principal Investigations. However, the plan for EREP data described here reflects the characteristic features of all of the Skylab data evaluation plans.
1 Compounds formed of elements of the II and the VI group of the Periodic System of Elements Such compounds are mostly semiconductors.
2 Compounds formed of elements of the III and V group of the Periodic System of Elements.
3 Eloda is a bright green, fast growing plant found in fresh water ponds.