What was the skylab built for

The instrument demonstrated clearly that there were bumps and troughs on the surface of the oceans. The primary measurements accomplished by the altimeter were individual return waveforms, backscattered signal power, and the round-trip ranging time. The S altimeter hardware had five selectable modes of operation as shown of Table 5.

IF center frequency Bandwidth Preamplifier. Type Uncompressed pulse width Compressed pulse width Code. Binary phase code ns 10 ns 13 bit Barker code. Altitude tracking loop type Loop bandwidth Altitude output Altitude granularity Acquisition time. Digital, MHz logic 2 Hz 32 pulse average of 2-way delay 0. No of sample and hold gates Sampling gate width Gate spacing.

Table 4: Characteristics of the S radar altimeter system. Determine min decorrelation between return pulses as a function of surface conditions. Pulse pairs are transmitted with a spacing between adjacent pulse stepped through the following values: Concept based on rapid decrease in theoretical peak of the mean return power as the antenna scans off nadir.

Table 5 : Operating mode summary of S altimeter instrument. S Passive Microwave Radiometer in L-band :. S was a modified Dicke-type radiometer with tuned RF receiver, gain modulation, and H polarization. The system used a built-in calibration referenced to fixed hot and cold load input. The precision of the temperature measurement was 1 K. Data were recorded approximately three times per second, which resulted in a distance between centers of two consecutive resolution cells on the ground of 2.

All data were recorded on magnetic tapes. The S instrument was developed by NRL. The objective was to photograph the airglow, in particular at twilight, in several spectral bands within the VIS and mid-ultraviolet spectral range.

A further objective was to study the Earth's ozone layer by vertical photography, using some of the airglow equipment. The airglow objectives were further modified after SL-3, the second manned mission, to include infrared photography of the OH hydroxyl airglow because of the availability of IR film and the need for wider passband photography of the airglow. As the spacecraft traveled from sunset through night and into dawn. Guidance of the camera was required of an astronaut during exposures of up to 64 s long.

A tracking bracket was designed to move camera and guide telescope together as the astronaut maintained an illuminated rectile in position tangent to the VIS, unfiltered airglow band.

A main goal of Skylab was the study of the sun, in particular the corona with its flares and coronal transients, referred to as CMEs Coronal Mass Ejections , in several wavelength regions not accessible from Earth.

Several telescopes were available in ATM Apollo Telescope Mount to look at the sun in X-ray, ultraviolet, and H-alpha wavelengths, as well as in white light. The ATM canister [protective containment and instrument rack was as large as any solar observatory spar on Earth at the time, measuring 3. The solar telescopes on the ATM were not miniature models but full-sized observatory instruments, typically 3 m long and weighing, in all, more than kg. The ATM facility provided also vast capabilities for data recording in the early time frame.

High-resolution film cameras were used to record the various instrument observations. The astronauts had the task to service load and unload the cameras and return the film at the end of their missions Earth. Nearly thirty film canisters were exposed and returned to Earth, providing scientists with over , exposures.

A single control and display console in the MDA Multiple Docking Adapter adjacent to the ATM permitted manual operation and visual monitoring of all the experiments on ATM through selector switches, pointing controls, TV monitors, and a variety of indicators of experiment status, film usage, solar conditions, and other parameters. The astronauts worked with the scientists on the ground, via radio exchange, in planning new programs and modifying others. They kept watch for flares and devised their own new ways of predicting flare occurrence.

Skylab included eight separate solar experiments on ATM consisting of the following instruments. Most of these solar instruments were descendants of instruments used in experiments flown on earlier, unmanned solar spacecraft. S X-ray Spectrographic Telescope :. The objective was to obtain X-ray images of the sun over a wavelength range from 0. Use of selective filters and a transmission grating to obtain spectral information. The instrument provided a spatial resolution of approximately 2 arcsec on axis and had six broadband X-ray filters, each with a different transmittance curve.

The instrument provided a spectrographic mode and an imaging mode. Each X-ray picture is accompanied by a white-light picture, co-aligned with the X-ray image. The data were recorded on film. Approximately frames of film were available on each film magazine. One camera magazine was used during the first manned SL-2 Skylab mission. Two were used during the second mission SL-3 , and two magazines were exposed during SL In total, approximately 32, solar X-ray exposures were obtained.

The telescope photographically records high-resolution images of the solar corona in several broadband regions of the soft X-ray spectrum. It includes an objective grating used to study the line spectrum. The spatial resolution, sensitivity, dynamic range and time resolution of the instrument were chosen to survey a wide variety of solar phenomena. It embodies improvements in design, fabrication, and calibration techniques which were developed over a ten-year period.

The observing program was devised to optimize the use of the instrument and to provide studies on a wide range of time scales.

This experiment included also a photomultiplier counter consisting of a NaI crystal of about 5 cm 2 area and a covering window of 5. The counter operated in two modes: either the output went through a pulse-height analyzer, which provided 8 channels of counts from 10 keV to 80 keV, or the DC current was monitored and converted to a number proportional to the logarithm of the current.

Figure X-ray telescope with grating, showing generation of spectra of individual X-ray sources image credit: NASA. This grazing incidence telescope produced images of the sun in X-rays with wavelengths from 6 to 49 A, together with an X-ray event analyzer to monitor the total solar soft X-ray flux in several wavelength bands.

Images taken through 6 different filters were recorded on film which was then returned to Earth on return flights for processing. On a historical note, the S and S observations provided the first ever spaceborne X-ray imagery. These Skylab images clearly showed the utility of full-disk solar images for studies of coronal holes and solar flares.

The synoptic record of solar coronal structure provided by these images has enabled researchers to discover trends in the lives of solar active regions, X-ray bright points, coronal streamers and other solar wind structures, as well as the evolution of the solar magnetic field over an eight-month interval. Originally these images were acquired in orbit on photographic film, and processed by printing slides and paper images.

Years later, the micro-densitometer scans of the original film were made and stored on magnetic tapes. In dimensions and general characteristics, S and S were much alike. The principle difference between them was that S had three times less light gathering area, but was equipped with a different series of filters, which enabled it to record somewhat harder X-rays.

S was particularly successful in recording images of high spatial resolution, which showed the growth phase of solar flares in detail. S was developed by NRL. The objective was to record on photographic film a spectrum of the X-ray and ultraviolet radiation from the sun in the nm or 10 - A region, with modest angular resolution. Radiation in this spectral range is emitted by highly ionized atoms in the solar chromosphere and corona.

This is indicative of high-temperature atomic and plasma processes which are extremely difficult to duplicate on Earth. Instrument: Sunlight entered a narrow slit and impinged upon a grating under a very small angle of incidence.

Under conditions of grazing incidence, the gratings reflected sufficient energy even in the nm wavelength region soft X-ray region to make film recordings feasible when long-time exposures could be made. Thin metallic films in front of the slit blocked out undesired ultraviolet and visible light.

Also, to obtain a spectral scan of the nm region by tilting the grating. The study of relative spectral line intensities provides information about plasma composition, temperatures, and energy transfer processes in quiet and active solar phenomena. Bi-axial motion of the primary mirror generated the desired raster scanning pattern polychromator mode. In the grating scan mode, the primary mirror remained fixed while the grating is tilted to scan the entire operating spectrum past one or more of the photomultiplier detectors 7 detectors.

The signals from the detectors were transmitted to the ground by telemetry. The instrument was operated in both unattended and unmanned modes, but without the capability of fine pointing except when manned and the crewman in charge. Excellent results were obtained with the intensity data covering a wide dynamic range with high precision. The white light coronagraph was one of the principal ATM instruments for studying the sun's outer atmosphere, its corona. It was designed to photographically monitor the brightness of the solar corona over a wavelength range extending from - A.

The goal was to obtain high resolution, high sensitivity photographs of the solar corona from 1. Study of brightness, form, size, composition, polarization, and movements of the corona. Correlate the observations with solar surface events and with solar wind effects. Coronagraphs are designed to block out the image of the sun's disc and to take pictures of the faint corona which extends from the sun far into space.

Light scattering by optical elements and by structural surfaces must be carefully avoided. This instrument contained four coaxial occulting discs and photodetectors for alignment corrections. Pictures were recorded on 35 mm film; they were taken either in unpolarized light or in one of three possible orientations of plane polarized light. S operation took place in four photographic modes. In each mode, the shutter of the camera made three exposures of 0. In the first mode, the triple exposure was made at each of the four different positions of the polarization filter wheel.

In the second mode, the same sequence of 12 exposures was repeated continuously for 16 minutes. The fourth mode was the same as mode three, except that a shutter opening occurred every 32 seconds only; this mode continued until manually stopped. During the Skylab mission, the coronagraph obtained more than 35, broadband white-light photographs nm of the solar corona, both unpolarized and linearly polarized the latter through Polaroid HN filters.

Five cameras, each loaded pre-mission with a m long by 35 mm wide film roll, were recovered and replaced by astronauts on EVA maneuvers. The objective was to record monochromatic images of the entire sun in the emission lines of a spectral range from 17 to 63 nm extreme UV.

Information was obtained about the composition, temperature, energy conversion and transfer, and plasma processes within the chromosphere and lower corona. These data were correlated with results from simultaneous observations in the other wavelength regions. Among the most intense lines in this extreme ultraviolet region are those of helium, oxygen, neon, magnesium, and iron. The instrument was a slitless Wadsworth grating spectrograph using photographic recording.

Monochromatic, overlapping solar images of The instrument was designed to operate over two wavelength ranges with the grating normal located at A for the one and A for the other range the two spectral ranges were being photographed separately, with two angular positions of the grating.

The unused part of the solar spectrum was being reflected out into space in order to avoid unnecessary heating of the instrument. A thin aluminum filter in front of the film kept stray light out. Four film cameras, each loaded with film strips, were being used. SB was developed by NRL. The objective was to obtain XUV Extreme Ultraviolet spectra 97 to nm or A of small portions of the solar surface with high spatial and spectral resolution, and to obtain photograph spectra at various locations on and off the disc and across the limb, from 12 arcsec below to 20 arcsec above the limb.

Attempts were made to obtain spectra of flares and other active areas on the sun. Information on the change of the solar energy transportation mode from convection to plasma-dynamic shock waves was being derived from these observations. Also, details of structure, density, and temperature of the chromosphere and the lower corona were being studied.

The instrument consisted of a single mirror telescope and a double grating spectrograph. The telescope mirror was an off-axis paraboloid of 1 m focal length and 54 mm x mm clear aperture. The mirror formed on the entrance slit of the spectrograph a solar image of 9. A pre-disperser grating assembly with two gratings was being used to generate a light beam containing only the desired wavelength regions elimination of stray light. The entrance slit admitted light from a 2 arcsec x 60 arcsec area on the sun.

Image detection was done with photomultipliers. The photoelectric detection technology employed offered such features as increased precision of the intensity measurements and a wider dynamic range coverage over the photographic recording technique. The objective was to use two telescopes imaging the sun in the red light of the hydrogen-alpha line Balmer series to provide a visual aid to the astronauts and a photographic record of solar conditions during ATM solar observing periods study of H-alpha emission from the sun during solar flares.

Each of the telescopes had a mechanically movable cross-hair: that of telescope I was being aligned with the boresight of Experiment S, that of telescope 2 with the boresight of Experiment SB. Alignment was being accomplished by crew members, using the solar limb in two right-angled directions as reference system.

Figure Construction detail of the telescopic camera for hydrogen-alpha photography image credit: NASA. The hydrogen-alpha telescope 1 provided simultaneous photographic and TV pictures; its resolution was 1 arcsec at a field of view FOV of 4. Telescope 2 operated only in the TV mode, with a resolution of about 3 arcsec.

Each telescope had a zoom capability, varying the FOV between 4. Selection of the desired spectral line Gegenschein and zodiacal light intensity and polarization. Measure the surface brightness and polarization of the night glow over a large portion of the celestial sphere in the visible light spectrum and determine the extent nature of the spacecraft corona during daylight.

Mass, speed and chemical composition of interplanetary dust. Determine the mass distribution of micrometeorites in near Earth space. Faint X-ray source survey. Survey a portion of celestial sphere for galactic X ray sources in the 0.

UV Panorama Experiment - photometer for stellar spectrography and a wide-field imaging camera. Obtain wide field of view photographs of individual stars and extended star fields in the UV range. Transuranic Cosmic Ray Experiment. Provide detailed knowledge of relative abundance and energies of the nuclei in cosmic radiation. Some pioneering Skylab achievments:. A total of 46, photographs were made of the Earth's surface.

One problem with this proposal was that it required a dedicated Saturn V launch to fly the station. At the time the design was being proposed, it was not known how many of the then-contracted Saturn Vs would be required to achieve a successful Moon landing.

An airlock would be attached to the hydrogen tank, in the area designed to hold the LEM , and a minimum amount of equipment would be installed in the tank itself in order to avoid taking up too much fuel volume. Floors of the station would be made from an open metal framework that allowed the fuel to flow through it.

After launch, a follow-up mission launched by a Saturn IB would launch additional equipment, including solar panels, an equipment section and docking adapter, and various experiments. An early " wet workshop " version of Skylab.

The agency decided that the Air Force station was not large enough, and that converting Apollo hardware for use with Titan would be too slow and too expensive.

Design work continued over the next two years, in an era of shrinking budgets. The success of Apollo 8 in December , launched on the third flight of a Saturn V, made it likely that one would be available to launch a dry workshop.

Although this would have allowed them to develop von Braun's original S-II based mission, by this time so much work had been done on the S-IV based design that work continued on this baseline. With the extra power available, the wet workshop was no longer needed; [28] the S-IC and S-II lower stages could launch a "dry workshop", with its interior already prepared, directly into orbit. A dry workshop simplified plans for the interior of the station.

Astronauts were uninterested in watching movies on a proposed entertainment center or playing games, but did want books and individual music choices. Skylab food significantly improved on its predecessors by prioritizing edibility over scientific needs. Each astronaut had a private sleeping area the size of a small walk-in closet , with a curtain, sleeping bag , and locker. Rescuing astronauts from Skylab was possible in the most likely emergency circumstances.

The crew could use the CSM to quickly return to Earth if the station suffered serious damage. If the CSM failed, the spacecraft and Saturn IB for the next Skylab mission would have been launched with two astronauts to retrieve the crew; given Skylab's ample supplies, its residents would have been able to wait up to several weeks for the rescue mission.

Launch of the modified Saturn V rocket carrying the Skylab space station. A Saturn V originally produced for the Apollo program—before the cancellation of Apollo 18, 19, and 20—was repurposed and redesigned to launch Skylab. Skylab was launched on May 14, by the modified Saturn V. The launch is sometimes referred to as Skylab 1, or SL Debris from the lost micrometeoroid shield further complicated matters by pinning the remaining solar panel to the side of the station, preventing its deployment and thus leaving the station with a huge power deficit.

Immediately following Skylab's launch, Pad A at Kennedy Space Center Launch Complex 39 was deactivated, and construction proceeded to modify it for the Space Shuttle program, originally targeting a maiden launch in March The manned missions to Skylab would occur from Launch Pad 39B. Solar prominence recorded by Skylab on August 21, [47]. The first manned mission, SL-2, launched on May 25, atop a Saturn IB and involved extensive repairs to the station.

The crew deployed a parasol-like sunshade through a small instrument port from the inside of the station bringing station temperatures down to acceptable levels and preventing overheating that would have melted the plastic insulation inside the station and released poisonous gases. The crew conducted further repairs via two spacewalks extra-vehicular activity, or EVA.

The crew stayed in orbit with Skylab for 28 days. Two additional missions followed, with the launch dates of July 28, SL-3 and November 16, SL-4 , and mission durations of 59 and 84 days, respectively.

The last Skylab crew returned to Earth on February 8, Skylab orbited Earth 2, times during the days and 13 hours of its occupation during the three manned Skylab expeditions.

Each of these extended the human record of 23 days for amount of time spent in space set by the Soviet Soyuz 11 crew aboard the space station Salyut 1 on June 30, Skylab 2 lasted 28 days, Skylab 3 56 days, and Skylab 4 84 days. Astronauts performed ten spacewalks, totaling 42 hours and 16 minutes.

Skylab logged about 2, hours of scientific and medical experiments, , frames of film of the Sun and 46, of Earth. Owen Garriott performing an EVA in Astronauts also found that bending over in weightlessness to put on socks or tie shoelaces strained their stomach muscles.

Breakfast began at 7 AM. Astronauts usually stood to eat, as sitting in microgravity also strained their stomach muscles. They reported that their food—although greatly improved from Apollo—was bland and repetitive, and weightlessness caused utensils, food containers, and bits of food to float away; also, gas in their drinking water contributed to flatulence.

After breakfast and preparation for lunch, experiments, tests and repairs of spacecraft systems and, if possible, 90 minutes of physical exercise followed; the station had a bicycle and other equipment, and astronauts could jog around the water tank.

After dinner, which was scheduled for 6 PM, crews performed household chores and prepared for the next day's experiments. Following lengthy daily instructions some of which were up to 15 meters long sent via teleprinter, the crews were often busy enough to postpone sleep. The station offered what a later study called "a highly satisfactory living and working environment for crews", with enough room for personal privacy.

The figure lists an overview of most major experiments. Skylab was abandoned after the end of the SL-4 mission in February , but to welcome visitors the crew left a bag filled with supplies and left the hatch unlocked. The studies cited several benefits from reusing Skylab, which one called a resource worth "hundreds of millions of dollars" [67] with "unique habitability provisions for long duration space flight.

Proponents of Skylab's reuse also said repairing and upgrading Skylab would provide information on the results of long-duration exposure to space for future stations. The station had not been designed for extensive resupply. Weitz and science pilot Joseph P. Kerwin — was delayed as the astronauts began training for the new mission to make the station habitable.

Launching 10 days later, on May 25, the crew's first challenge, just hours after launch, was to attempt to deploy the solar array during a spacewalk. However, initial attempts met with no luck as a metal strip holding it down refused to give way. Crewmembers emerged from an expected communications blackout in a foul mood, according to an official NASA account of the mission. Realizing the tools they had with them that day would not work, Conrad abandoned the exercise and focused on trying to dock his spacecraft with the station.

Unfortunately, the docking mechanism failed and the crew had to depressurize the spacecraft and bypass electrical connections to achieve it. In subsequent days, Conrad's crew erected a sun shade , successfully deployed the stuck array, and began operational work aboard the station.

While the incident was frustrating for the teams involved, it also demonstrated that it was possible to fix a badly damaged space station while it is in orbit. With the worst of the mechanical problems behind, NASA and the three Skylab crews focused on matters pertaining to long-duration spaceflight. Everything from the crew's exercise time to nutritional requirements to scheduling came under scrutiny and debate. Lousma and scientist Owen K. Garriott — impressed NASA with its productivity.

The crew finished its assigned tasks much faster than expected, and clamored for more. While the pace was impressive, it set within NASA some false expectations for how much a group of astronauts could accomplish.

Things weren't always that smooth between the ground and space. Skylab's third crew in particular complained repeatedly about being overloaded with tasks and superhuman expectations. Some have said the crew did a mutiny in orbit, although others characterize it more as a temporary refusal to do more work.

Whatever the situation, the unhappiness prompted a discussion between the ground and space where the two sides brought their mutual concerns to the table. Things never got that bad again between the crew and the ground controllers, but none of the astronauts — Commander Gerald P.

Carr, pilot William R. Pogue and scientist Edward R. Gibson — flew in space again. Carr later said he regretted having waited for several weeks before airing his concerns. In between adapting to a longer mission, crews focused on the science.

A solar telescope mounted on the station allowed the astronauts to observe solar flares in action, although an early crewmember joked that he was left wishing for "supernormal" flares. One crew also observed Comet Kohoutek as it swung closest to Earth.