1974 (11th) Vol.2 Technology Today for The Space Congress® Proceedings Tomorrow Apr 1st, 8:00 AM Apollo Telescope Mount Experiments Technology W. C. Keathley Chief, ATM Experiments Branch, Marshall Space Flight Center, Huntsville, Alabama Follow this and additional works at: https://commons.erau.edu/space-congress-proceedings Scholarly Commons Citation Keathley, W. C., "Apollo Telescope Mount Experiments Technology" (1974). The Space Congress® Proceedings. 2. https://commons.erau.edu/space-congress-proceedings/proceedings-1974-11th-v2/session-1/2 This Event is brought to you for free and open access by the Conferences at Scholarly Commons. It has been accepted for inclusion in The Space Congress® Proceedings by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. APOLLO TELESCOPE MOUNT EXPERIMENTS TECHNOLOGY W. C. Keathley, Chief ATM Experiments Branch Marshall Space Flight Center Huntsville, Alabama ABSTRACT The Skylab Apollo Telescope Mount (ATM) experi­ Earth T s atmosphere and, during the final Skylab ments, consisting of a white light coronagraph, flight, on Comet Kohoutek. four ultraviolet instruments, two X-ray telescopes and two Hydrogen-alpha telescopes, observed the To complement the data acquired by the orbiting Sun daily for nine solar rotations. The results ATM, hundreds of scientists around the world con­ have only begun to be evaluated, but it is already ducted simultaneous observations from their re­ apparent that many theories of solar physics will spective ground based observatories undergo significant revisions as results are fur­ ther developed. The ATM instruments were indi­ Now that the Skylab mission has been completed vidually larger, more complex, and provided better and a wealth of data has been returned to Earth spatial resolution than previous solar satellite and the waiting scientists, extensive data analy­ instruments. An additional major advantage of the sis programs have been started. The massive telescope complex was its ability to simultaneous­ scientific yield will take years to evaluate but ly collect multispectral data of specific solar it is already apparent, from quick-look data, that phenomena. To maximize the scientific benefits of many theories of solar energy and mass transfer the orbiting observatory, a coordinated observing must be revised. program involving worldwide ground-based observa­ tories was conducted. A description of the Skylab, Limited space precludes a complete discussion of the ATM and the ATM experiments will be given. The all ATM experiments. Many technical papers could daily process of flight planning and execution will be and surely will be written on each of the fol­ be described. Examples of scientific data and some lowing sections. The contents of this-paper, preliminary findings will be presented. therefore, will consist of a brief description of: (1) the Skylab space station, the ATM module, and the ATM scientific instruments; (2) techniques INTRODUCTION used by flight and ground teams to collect the data; (3) samples of the solar data and, (4) some The Skylab Apollo Telescope Mount (ATM) scientific preliminary scientific findings. instruments recently completed daily observations of the Sun for nine solar rotations involving a total of 2203 hours. The line of sight from orbit HARDWARE DESCRIPTION/PERFORMANCE was a minimum of 400 kilometers above the Earth. These observations have provided scientists with Skylab Description the most complete set of continuous solar data ever accumulated and have been compared to The Skylab Space Station was launched on May 14, Galileo f s first look through his telescope cen­ 1973, from Cape Kennedy, Florida. As shown in turies ago. Spectral coverage of the instrument Figure 1, the launch configuration consisted of complex ranged from soft X-rays to the visible the Saturn V launch vehicle, which included the wavelengths. The spatial resolution of each in­ S-IC first stage, the S-II second stage and inter­ strument was an order of magnitude better than stage structure, and the payload, which included any similar instrument flown on previous satel­ the space station, instrument unit and the payload lites. A major advantage of the ATM was the shroud. The orbiting configuration, shown, in availability of astronaut observers because they Figure 2 y consisted of the Command and Service could point the instruments precisely at very Module (CSM), which was used to ferry the crew; small targets, and immediately react to unpredict­ the Multiple Docking Adapter (MDA), which pro­ able transient events. These capabilities were vided docking capability for the CSM, also housed beyond the competence of unmanned satellites. the ATM control panel and provided storage space; the Airlock Module (AM) through which the crew In addition to solar observations, the design of egressed for extra-vehicular activities; the the ATM instruments offered unique capability for Orbiting Workshop (OWS), which provided space for collecting high quality data on the Mercurian storage, experiment activities and crew quarters; atmosphere, Earth-Moon Lagrangian points, the and the ATM' module, which included the solar , . 1-1 instruments and their supporting equipment. were confined to the coarse pointing and control system (CMC failure) and the aperture doors. The The original mission plan called for a Saturn I-B CMC failure affected the maneuver times during launch of the first flight crew in the Apollo CSM excursions out of solar inertial mode and there­ on May 15, 1973, the day following orbital in­ fore indirectly affected ATM experiment operation. sertion of the space station. This plan was al­ Several intermittent stalls and subsequent com­ tered to provide sufficient time to prepare equip­ plete failure of the aperture doors occurred dur­ ment and train astronauts for in-orbit repair of ing flight. In all cases the problems were re­ the space station. The repair became necessary solved by utilizing a second drive motor and because one of the solar arrays and the meteoroid manually opening the door during a subsequent EVA. shield ripped away from the OWS during the May 14 launch. The repairs included the deployment of a curtain to thermally protect the portion of the ATM Experiment Instruments space station exposed by the loss of the meteoroid shield, and the manual deployment of the remaining The ATM experiment instruments consisted of the OWS solar array, which had jammed in a closed following : position. The flight crew was launched on May 29, and, almost immediately, deployed the curtain and 1. White Light Coronagraph (S052); built by Ball freed the jammed solar array, thereby literally Brothers Research Corporation of Boulder, Colo­ saving an otherwise-crippled space station. This rado , under contract to the High Altitude Observa­ was the first proof of the astronauts 1 worth to tory (HAO), also of Boulder. Dr. R. MacOueen of the Skylab program. There were many more to come. HAO is the principal investigator. Figure 3 shows the station after the repairs were made. 2. X-Ray Spectrographic Telescope (S054) ; built by American Science and Engineering Corporation (AS&E) of Cambridge, Massachusetts. Dr. G. S. ATM Module Description Vaiana of AS&E is the principal investigator. The ATM was originally designed as a self-suffi­ 3. UV Scanning Polychromator Spectroheliometer cient, free-flying module and therefore contained (S055); built by Ball Brothers Research Corpora­ all the subsystems necessary to support the solar tion under contract to Harvard College Observa­ instruments contained on its optical platform. tory, Cambridge, Massachusetts. Dr. E. Reeves of During the evolution of the Skylab program, a the Observatory is the principal investigator. decision was made to hardmount the ATM to the MDA and use the ATM coarse pointing and control system 4. XUV Spectrograph/Spectroheliograph (S082) ; to maneuver and stabilize the entire Skylab and to built by Ball Brothers Research Corporation under share its large supply of electrical power with contract to the Naval Research Laboratory (NRL) , other Skylab modules. Washington, D. C. Dr. R. Tousey of NRL is the principal investigator. Figure 4 shows views of the ATM looking from the Sun end, from the side and from the MDA end. The 5. X-Ray Telescope (S056) ; built by Marshall Sun-end view shows the doors which protected the Space Flight Center (MSFC), Huntsville, Alabama. solar instrument apertures, sections of the four Mr. J. Milligan of MSFC is the principal investi­ solar arrays that provided electrical power, two gator. VHF telemetry antennae, two command receivers, a solar shield which thermally protected rack com­ 6. Two H-Alpha Telescopes; these telescopes were ponents and the Sun-end work station. The latter the primary means for boiresight pointing for the provided hand and foot restraints for the crew so ATM experiment instruments. The H-Alpha No. 1 that the astronauts could hold fast while removing instrument was actually a part of the S055 Ex­ and installing two ATM photographic cameras. The periment. The instruments were built by Perkin- side view shows the rack structure which supported Elmer of Norwalk, Connecticut. the pointing and control system, the solar arrays, the electrical power storage and distribution sys­ All ATM experiments were managed and integrated tem, the instrumentation and communication system, into the Skylab Program by the National Aeronau­ the center work station that provided access to tics and Space Administration's