Apollo Experience Report Communications Used During Recovery Operations

8/8/2019 Apollo Experience Report Communications Used During Recovery Operations

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N A S A T E C H N I C A L NO T E N A S A TN 0-7686

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F I L EC O P Y

APOLLO EXPERIENCE REPORT -COMMUNICATIONS USED D U R I N GRECOVERY OPERATIONS

by John E, HooverLyndon B, Johnson S p a e CenterHozlston, Texas 77058N A T I O N A L A E R O N A U T I C S A N D S PA CE A D M I N I S T R A T I O N W A S H I N G T O N , D. C. M A Y 197


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I ____^ ".1_4 .._.I_-.__ _I_.______ll______l__l_.l__ _ _ 3. Recipient's Catalog No.1_

May 1974

2. Government Accession No.1. Report No.TN D- 7686 --.----I- I- I -.-4. Tit le and Subt it leAPOLLO EXPERIENCE REPORTCOMMUNICATIONS USED DURING RECOVERY OPERATIONS

7. Aut t ior (s )John E. Hoover, JSC

_...-.-- ----9. Performing Organizat ion Name and Address

Lyndon B. Johnson Space Cent erHouston, Texas 77058-.2. Sponsoring Agency Name and Address

National Aeronautics and Space AdministrationWashington, D. C. 20546 ~ - _ _-

8. Performing Organizat ion Report No----JSC S-398 -I--.-_. _.10. Work Unit No.I -_. -.924- 22- 30- 00- 7211. Contract or Grant No.

--13. Type of Report and Period CAveredTechnical Note

.--_-14 . Sponsoring Agency CodeI 1--6. Abstract

Apollo Program experience in recovery-support communications is reviewed, and the workingrelat ions hips among NASA, the Department of Defense, and commerc ial communications facil-it ie s a r e disc ussed. The organization, fa cilit ies, philosophy, and funding of recov ery-supp ortcommunications a r e described, The relocation of two recovery control centers is discussed,as are the functions of pri mary and secondary recovery ships, aircr aft, and relay satellites.The possibility of using ship s of opportunity fo r recover y operati ons is considered. Finally,the means by which money, manpower, and re so ur ce s have been saved and longlines leasedar e delineated.

17. Key Words (Suggested by Author(s) )Communication SatellitesSpacecraft Recovery

'Rescue Operations* Spacecraft LandingWater Landing

18. Distribu t ion StatementSubject Category 31

19. Secu rity Classif. (of this repo rt) 20. Security Classif. (o f this page)None None

21. NO. of Pages 22. Price10 $3.00


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APOLLO EXPER IENCE REPORTCO M M UN I CAT I O NS USED DUR I NG RECOVERY O PERATIO NS

By J o h n E. Hoove rL y n d o n B. J o h n s o n S pa ce C e n t e r

S U M M A R YA dedicated communications network w as established to provide the capability forrap id response of the recovery fo rces in support of the Apollo Progr am. During the

Apollo Progr am , two recovery control cen ters were relocated, a new philosophy con-cerning teletype communications w a s adopted, and sate llit es wer e used to furnish com-munications between primary recovery ships and the recovery control cent ers . Theus e of existing NASA and Department of Defense faci li ti es to the maximum extent poss i-ble and the implementation of seve ral other measu res resulted in an efficient, reli ablecommunications system at a relatively low cost to NASA.

I NTRODUCTI O NBefore the operational phase of the Apollo Program, a dedicated voice and tele-

type communications network existed t'o provide rap id command and cont rol of recoveryfor ce s and to keep the staff in the Mission Control Center (MCC) informed of recovery-fo rc e acti viti es and sta tus. This network had been established during the Gemini Pro-gr am because nor mal common-user Department of Defense (DOD) communicationschannels were not a l w a y s responsive enough and, in many cases, did not extend to cer-tain areas of the world where recovery f orce s would be positioned to provide e ithe r con-tingency or planned landing-area support. During the Apollo Program, the recoverycommunications network underwent cert ain modifications as a re su lt of ef fort s to im-prove efficiency, to provide gre ate r reliability, and to reduce costs . The most signif-icant communications changes a re discussed in this re port .

RECOVERY COM MUN I CAT IONS0rg a n i z a t i on

The responsibility of providing recovery support for the Apollo Prog ram was as-signed to the DOD as in Project Mercury and in the Gemini Prog ram. The DOD Managerf o r Manned Space Flight Support Operations, appointed by the Secreta ry of Defense,coordinated and provided operational control of the var ious Apollo miss ion- support


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operations. The DOD Manned Space Flight Support Office (DDMS) was the focal pointfo r receiving NASA support requests and for administering the plans and policies ofthe DOD Manager. The responsibil ity of providing recovery suppor t for specific areasof the world was delegated to various mil itary commands by the Secretary of Defensethrough the Joint Chiefs of Staff; the type of suppor t and the geographical a r e a of com-mand responsibility were consistent with normal capabilities and th ea te rs of operation.

FaciI tiesTo control and communicate with the recovery f or ce s, the responsible command-e r s established recovery control cent ers at appropria te locations. The facility thatprovided overall direction was the Recovery Operations Control Room (ROCR), locatedwithin the MCC at the NASA Lyndon B. Johnson Space Center (JSC) (formerly theManned Spacecraft Center (MSC)) in Houston, Texas. During a mission, the ROCR ismanned by both NASA and DOD recovery personnel. The principal means of communi-cation among the ROCR, the recovery control centers, the recovery ships, and the re-mote aircraft-staging bases during mission operations are summarized as follows.

Communications link Method of communicationLeased longlines and dedi-etween the ROCR and the recovery cated DOD circuitscontrol center s

Between the recovery control Satelli es and high -frequencycen ters and the recovery ships radioBetween the recovery control Combinat ions of preceding

centers and the remote aircra ft-staging bases methods

The recovery-communications network in us e during a typical lunar-landing miss ion isshown in figure 1.

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Figure 1. - Functional diagram of recovery communications during a typicallunar- landing mission.

R e c o v e r y C o n t r o l C e n t e r R e l o c a t io n sAtlantic recovery control center. - The Atlantic recovery control cent er (RCC),serv ing Commander Task Force 140 (C TF 140), w a s fi rs t located in the Mercury Con-tro l Center at the John F. Kennedy Space Center (KSC); this Mercury Control Centerwas used until 1965 when the MCC at MSC w a s activated. While the plans for deactiva-ting the Mercury Control Cent er were being made, a study was conducted to determinethe best location for the Atlantic RCC. Several locations were considered, as well a sits collocation with the ROCR in Houston. The final decision, however, w a s to locate theAtlantic RCC in the building occupied by CTF 140 at the Naval A i r Station i n Norfolk,Vi rg i n i a . The new RCC w a s completed in time to conduct an operational checkoutduring the Apollo 5 mission. In addition to the tr av el and pe r diem savings realized

by locating the Atlantic RCC in Norfolk, other advantages were gained. The NorfolkNaval Communications Station w a s able to provide not only additional high-frequencytr an sm it te rs and rece iv er s for backup to the dedicated high-frequency recovery-communications facilities at KSC, but also a high-frequency ci rcui t f o r air control ofHC- 130 re sc ue ai rc ra ft supporting the Atlantic launch abort areas. In addition, per-sonnel fo r maintenance of RCC teletype and cryptographic equipment were readilyavailable.

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Europe/Africa recovery control center. - The Europe/Africa RCC is collocatedwith the Search and Rescue (SAR) Command Center a t Ramstein A i r Base, Germany,where the 40th Aerospace Rescue and Recovery Wing (formerly the Atlantic AerospaceRescue and Recovery Center) was responsible f o r providing Apollo s ea rc h and recoverysupport fo r contingency landings in Africa and in par ts of the Atlantic and Indian Oceans.Fo r recove ry operations during the Apollo missions, special Aerospace Rescue andRecovery Service ai rc ra ft were positioned a t Mauritius Island, at La jes Field in theAzores, and a t Ascension Island. The SAR Command Center for these a ir cr af t waspreviously located at Moron A i r Base i n Spain but was moved to Ramstein, Germany,to reduce trave l and pe r diem expenses and to save manpower.Recovery Ship Communications

Primary recovery ship. - The Apollo Pr og ra m effected two significant changes topr imar y recovery ship (PRSJ communications- he use of a high-frequency communi-cations relay ship and the us e of shipboard communications- relay-sate llite termin alsto provide ship/shore radio links. Although PRS communications in the Atlantic Oceanhad never presented any significant difficult ies, communications in the Pacific Oceanwere expected to be difficult because of the g reater distance involved and the lack ofexperience in communicating to certain pa rt s of that ar e a of the world.Because the Apollo 8 recovery was to occur approximately a t su nr is e (when high-frequency communications a r e usually of marginal quality), U . s. Navy officials selectedthe U . S. S. Arlington, a communications relay ship, as the PRS. The time availablefo r testing was bri ef, however, and the limited capability of the U . S. S. Arlington toperform real- time voice-relay functions w a s not realized until during the mission. Fo rtest purposes and as a secondary backup, Goddard Space Flight Center (GSFC) person-nel instal led an applications technology sate llit e (ATS- 1) very-high-frequency (vhf) te r-minal aboard the PRS. Although the terminal had not been designed for efficientshipboard use ( e . g . , the antenna had to be steer ed manually), communications from thePRS were very good at times.Immediately after the Apollo 8 mission, Naval Elec tronics Laborato ry personnelwere asked to design and build a shipboard terminal to operate in conjunction with theDOD-sponsored Lincoln Experimental Satellite (LES-6) and the soon-to-be-launchedtactical satellite (TACSAT); both sate llite s were to ope rate in the 225- o 400-megahertzfrequency range. Meanwhile, GSFC personnel redesigned and rebuilt the ATS termi nalso that by the time of the Apollo 9 mission both the ATS and the LES-6/TACSAT sy st em scould undergo full-sca le checkouts aboard the U . S. S. Guadalcanal, the Atlantic OceanPRS. These te st s, conducted under operational conditions, we re very successful; infact , during a sudden ionospheric disturbance that suppr essed al l high-frequency com-munications, the ATS provided the only means of sh ip/shore communications. The r e -sults of the Apollo 9 te st s indicated that the ATS and the LES-6 terminal could provideexcellent ship/shore recovery communications.Meanwhile, U. S. Navy officials had modified the U. S. S. Arlington to enable her toprovide real-time voice relay, and she was assigned the duty of furnishing command andcontrol communications fo r the Apollo 10 miss ion in addition to furnishing satelli tecommunications with the U . S. S. Princeton, the PRS. Communications through the

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U . S. S. Arlington during the Apollo 10 mission were grea tly improved over those duringthe Apollo 8 mission. Likewise, the TACSAT performance was successful, and CTF 130requested satellit e support fo r the Apollo 11 mission.The PRS designated fo r the Apollo 11mission was the U. . S. Hornet. Favorable

high-frequency propagation predictions and the success of sate llite communications onthe Apollo 10 miss ion indicated that the ship communications facili ties and the TACSATand ATS could fulfill the communications requirements for this mission. Live televi-sion coverage of recovery operations was scheduled, and, because the onboard presspool elected to lease teletype c ircuits fro m a commercial c a rr ie r which provided thetelevision satellite circuit, the U . S. S. Hornet was rel ieved of having to provide thecustomary ship/shore teletype circuit for relaying written pr e ss traffic to the HoustonNews Center at MSC. Although the TACSAT did develop a noise condition during theApollo 11 mission and some degradation in voice cir cu it s was experienced, satisfac torycommunications were achieved during recovery by shifting fr om duplex to simplexmodes, adjusting power budgets, and limiting TACSAT us e to essential communications.After the command module (CM) recovery , the PRS circuit was used extensivelyto coordinate activities such as hardware and experiment data removal, film removal,and postflight medical. examinations.Secondary recovery ship. - Although a secondary recovery ship (SRS) was lesslikely to be called on for recovery support than a PRS, the requirement for r eliablecommunications still existed. Fewer circuits were required, however. A destroyerwas usually designated as an SRS although, in some ca se s, other ships such as oilershad been used. Because their normal missions did not require it, destroyers and oilersdid not have the communications capabilit ies, either in numbers of c ircuit s o r in radi-ated power output, that ships such as ai rcraf t car r ier s o r helicopter ca rr ie rs had.When secondary recovery ships had to be several thousand miles from an RCC, spec ial

meas ur es we re taken to augment the normal communications capabilities, either by theuse of remote shore-based tr ans mit ter s and receivers or by the installation of specia lequipment on the ships.Communications in the West Pacific and Mid-Pacific we re furnished by navalcommunicat ions stat ions in Hawaii and Japan. Because the Pacific RCC, servingCT F 130, w a s located in Hawaii, a leased undersea cable was required for r emote key-ing of the tr an smit te rs at the naval communications station in Japan. Support was als oprovided by the naval communications station i n Guam. The U.S. A i r Force Easter nTe s t Range provided high-frequency transmit ters and rece iver s for use by C TF 140 incommunicating with Atlantic secondary recovery ships.End-of-mission ai rc ra ft communications. - Although the accuracy of the Apolloguidance syst em and live television coverage of recovery did much to less en the require-ment fo r a rea l-time narrative of activities from the recovery scene, the need for com-mand and control communications between recovery commanders and their forces stillexis ted. An Apollo range instrumentation ai rcr aft w a s near the recovery are a to relay(to MCC in real time) conversation between the astr onaut s and the recovery f orce sbeing conducted on 296.8 megahertz . In addition, a specially configured helicopter w a sstationed over the PRS to provide relay of 296.8-megahertz transmission to the PRS i fthe CM landed out of line-of-sight vhf communications range to the PRS. The PRS then

relayed to the RCC, by high frequency, the act ivit ies being repor ted on 296.8 megahertz.


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Rescue aircraft, stationed 165 mi le s up range and down range of the ta rget point togive assistance should the CM land near them, were controlled by the PRS on anothercircuit, either very high frequency o r high frequency.Ships of opportunity. - A ship of opportunity, such as a merchant vessel, couldhave been called on had a contingency landing occur red far f rom a dedicated recovery

ship. Although requesting ass ist ance fr om a ship of opportunity w a s never necessary,the possibility of doing so was investigated. Information about ships near the ar ea ofin te re st was obtained fr om the U.S. Coast Guard Automated Merchant Vessel ReportCenter . Available informat ion included data about U. S. and friendly merchant shipping.If a U. S. S. or U.S.N.S. vessel had been called on, communications would havebeen handled through normal Navy channels, such a s the fleet broadcast. Merchantvess els presented a grea ter problem. Although most merchant vessels did not main-tain a 24-hour-a-day communications watch, they were requ ired to have automat ic-ala rm receivers on 500 kilohertz. When an al ar m signal w a s sent by an SAR agency,al l ship s receiving the signal inquired on that frequency whether assis tanc e was required.Several test emergencies we re simulated to determine the time required f or amessage to reach merchant vess els in the Atlantic Ocean. Test mess ages were sentthrough commercial facilities to selected ships. These e xe rc ise s indicated that an ade-quate number of ships was present in each selec ted ar ea , but the effectiveness of com-mercia l ship/shore telegraphic communications in the ar ea s w a s considered to be onlymarginal. A major study effort was undertaken to determine more reliable means ofcontacting and using merchant shipping in support of recovery operations .

Te letype Corn mun at io nsDuring the Apollo Program, a significant change occurred in the philosophy of

teletype communications. A dedicated teletype network w a s originally established toprovide record communications and to s er ve a s a backup to the voice communicationssystem. A full-duplex circuit was extended fr om the MCC to F or t Detrick, Maryland(a major U. S. Army automatic teletype switching cent er) , f ro m which separa te ci rc ui tswere extended to each RCC. Because of the high degree of reliabil ity of voice ci rc ui tsbetween the ROCR and each RCC, the teletype backup proved to be of negligible benefit;even when a voice circuit fail ed, the circuit could usually be re st or ed before a teletypemessage could be sent and received. Fo r this reason, the dedicated teletype systemwas replaced by a common-user system to save both manpower and money.Before the Apollo 6 mission, a plan was developed for conducting t es t s with theDOD common-user (AUTODIN) syst em instead of the dedicated sys tem. During the

Apollo 6 mission, the dedicated ci rc ui ts we re activated, checked, and then put onstandby. All mission teletype messages we re then sent ove r the AUTODIN syste m.Several delays were noted, but these were attributable to message handling and deliverya t the receipt locat ions. By the time of the Apollo 7 mission, these problems had beenidentif ied, and the AUTODIN system w a s used thereafter. Traffic w a s handled throughthe MCC communications center and, during critica l or busy periods, an operatormanned the ROCR communications center . Had a contingency occurred, the capabilityexisted to establish a di re ct ROCR-RCC tele type link.

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T h e N A S A W o r l d w id e C o m m u n i c a t i o n N e t w o r k I n t e rf a c eAlternate communications links were identified and checked before a mission incase their usage became necessa ry. The primary link between the CT F 130 RCC inHawai i and the SAR aircraft-staging base in Australia w a s a high-frequency circuit.To provide a backup, local cir cui ts and procedures were established to allow recovery

fo rc es to use one of the NASA Worldwide Communication Network (NASCOM) cir cui tsbetween Hawa i i and Aust ralia. This arrangement worked very well, and means wereprovided to allow the recovery personnel at the staging base to monitor the C M air-to-ground communications on the ground operational support s ys tems (GOSS) ircuit.A t other locations near a tracking station o r NASCOM switching center, circuitswere installed to allow each RCC to monitor the GOSS circuit. These circuits were in-stall ed in Bermuda, Moron/Ramstein, Australia, Norfolk, and Hawai i . At Hawai i andMoron/Ramstein, voice-transmiss ion capability w a s also provided for contingency op-erati ons that required additional circuit s to the ROCR.The inser tion tracking ship , the U.S.N.S. Vanguard, w a s chosen to provide

launch abor t recovery support beginning with the Apollo 7 mission. Procedures wereestablished to allow CTF 140 to communicate with the U.S.N.S. Vanguard if necessary.Already existing cir cu its among the Norfolk station, the RCC, Cape Kennedy A i r ForceStation, and GSFC were configured and checked shortly before launch. In ca se of alaunch abort, GSFC personnel would have extended this ci rcui t to the U.S.N. S. Vanguardthrough one of the Manned Space Flight Network ship/shore links .

C O M M U N I C A T I O N S F U N D IN GV a l i d a t i o n a n d A p p r ov a l P r o c e d u r e s

To ensure t hat NASA real ized the great est value fr om each dollar spent for com-munications, validation and approval procedures were established. Before any NASAfunds wer e committed for e ither leased longlines or communications equipment, exist-ing capabiliti es were examined to determine whether o r not the required element or asuitable alte rnate w a s available. If a longline w a s required, for instance, the DefenseCommunication Agency (DCA) was tasked to provide the line fr om the DCA inventoryof circuits. If i t was necessary to lease the circuit, the DDMS Director requested fund-ing approval f ro m the Chief of the Landing and Recovery Division at MSC. If the requestw a s considered a valid requirement, the expenditure of NASA funds was approved.

Long1 n e C o m m u n i c a t i o n sThe Defense Commerc ial Communications Office (DECCO) of the DCA was respon-sible fo r all DOD-leased longlines from commercial carriers or other governments and,consequently, had extensive "buying power. '' When warranted , DECCO officials leaseda group of seve ra l ci rcui ts ( called telpak) between two points. Then, as other agenciesor commands used the circuit s, the cost for these circuits w a s prora ted among theus er s. The savings were as much as 50 percent as compared to the cos t of leasing

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directly from the commercial ca rr ie r. When circuits were not required (e. g. , betweenmissions), the circui ts could be put on standby and reserved for future use . Thus, onlya smal l monthly fee w a s paid to ensure that the circuits could be obtained for NASA useat a reduced rate when needed.CONCLUDING REMARKS

Operational cost s were reduced by such actions as relocating two recovery controlcent er s, using exist ing NASA and Department of Defense faci li ties where possib le, andtaking advantage of special rates for leasing longlines. A t the same time, ship/shorecommunications were improved by taking advantage of relay- satell ite technology. Thesemeasures resulted in an efficient, reliab le communications system at a relatively lowcost to NASA.

Lyndon B. Johnson Space CenterNational Aeronautics and Space AdministrationHouston, Texas, January 29, 1974924-22-30-00-72

8 S-398ASA-Langley , 1914


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Apollo Experience Report Communications Used During Recovery Operations