The Space Congress® Proceedings 1981 (18th) The Year of the Shuttle Apr 1st, 8:00 AM Experiences In Delta Mission Planning Jyri Kork Delta Mission Analysis Manager Follow this and additional works at: https://commons.erau.edu/space-congress-proceedings Scholarly Commons Citation Kork, Jyri, "Experiences In Delta Mission Planning" (1981). The Space Congress® Proceedings. 5. https://commons.erau.edu/space-congress-proceedings/proceedings-1981-18th/session-6/5 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]. EXPERIENCES IN DELTA MISSION PLANNING Mr. Jyri Kork Delta Mission Analysis Manager Goddard Space Flight Center, NASA ABSTRACT solve its initial problems in only three months and to score 22 successive successes In 1959 NASA decided to develop Delta as an in the next 3 1/2 years, establishing a new interim launch vehicle for medium payloads reliability record for the early dawn of until more sophisticated vehicles reached the Space Age. The pattern of surmounting operational status. In the twenty years difficulties and mastering hardships became that have followed, Delta has matured into somewhat of a Delta trademark, reflecting a versatile all-purpose launch vehicle, in the news media headlines such as the being utilized by various US government "Space Transportation Workhorse 11 and "The agencies, domestic industry, and a number Indomitable Delta. 11 of foreign governments, as well. The philosophy of the Delta launch vehicle Delta's 153 launches have included low cir­ was unorthodox in its inherent simplicity: cular orbits, sun-synchronous, earth-syn­ to utilize the latest up-to-date technology chronous, polar, lunar, and interplanetary and flight proven hardware, to minimize the missions. Delta's 'firsts' include the necessity of developing totally new flight first international satellite, the first components, while aiming for optimum per­ synchronous transfer orbit, the first polar formance, reliability, and cost effective­ launch from ETR, and the first lunar orbiter ness. Especially the stress on the cost without a midcourse velocity correction. effectiveness accounted for the spectac­ ular popularity of the early Delta launch Typical Delta mission analysis methods and vehicles among the 'poor people of outer results are reviewed: feasibility studies, space 1 — non-government missions, the trajectory shaping, payload, orbit and reimbursable launches. In this respect — launch window optimizations, range safety without any .false modesty — Delta has studies, orbit injection error analyses, probably been one of the best United States radar tracking coverage, and vehicle sepa­ good will ambassadors in numerous widely ration dynamics. A number of more pictur­ separated areas of our common world. esque cases of the above missions analyses are highlighted among the past 153 missions, Another basic Delta philosophy was to 'please as well as among the approximately 40 future the customer 1 . It involved many extra week­ missions presently scheduled for the Delta ends of studies in the area.s not spelled out launch vehicle. in the formal contract: alternate launch windows, orbit optimizations over and beyond the call of duty, celestial mechanics lec­ 1) INTRODUCTION tures to foreign scientists just starting out on their road to the stars. In the beginning the Delta launch vehicle was modest and unassuming, The first launch But above all the Delta launch vehicle placed attempt on Friday the 13th, May 1960 ended a premium on versatility. Missions to be like the first launch of Vanguard; an un­ considered covered the whole spectrum of the qualified failure. There was but one basic space studies. Orbits ranged from the low difference: Delta — using a design based circular ETR to the high circular WTR on the Vanguard second stage — was able to launches, geosynchronous transfer coast 6-32 orbits, highly elliptic probes, to lunar, propel"!ant rocket X-258, developed for Scout. and even interplanetary missions. Quite properly, it was called Delta C. Both configurations were popular at their time: Delta's 153 launches and 40 presently sched­ 9 Delta B-s and 12 Delta C-s were launched. uled future missions will be discussed in the following technical review paper. The trend of Delta performance improvements developed into a genuine trademark. An exasperated aerospace engineer (not totally 2) LAUNCH HISTORY sympathetic to Delta) once explained that launch vehicle statistics can only be cal­ A direct outcome of the agreement of the culated if configurations remain identical, United States in 1955 to participate in the which "is true for all of the vehicles but International Geophysical Year (IGY) was Delta, for which some wag has remarked that the development of the Vanguard three-stage 'no two Delta flights have used identical vehicle. In 1959 NASA decided to develop configurations 1 . 11 Delta as an interim launch vehicle for medium-class payloads until more sophisti­ Aerospace engineers have been known to occa­ cated vehicles (such as Scout and Agena, sionally exaggerate. Actually, there have then under development) reached operational been many Delta launches using the same status. The Vanguard second stage and the configuration. Of the sum total of 32 Delta Vanguard third stage X-248 were adapted to flight configurations (ref. 2, 3, 4) two the Thor booster to become the original and were used definitely more than once: Delta the first Delta configuration. E was flown on 22 missions and Delta 2914 on 30 missions. On the other hand, among the The Douglas Aircraft Company (presently 32 development steps, four were used only McDonnell Douglas Astronautics Company - once (Delta J, 1900, 1410, and 1913), while MDAC) was and still is the prime contractor two became true space age collectors' items. for the Delta launch vehicle program. In Delta M6 and Delta 2314 were possible config­ the past 21 years this has been one of the urations that were never flown. Both, of most fruitful government/private industry course, were designed at the time when Delta cooperations. A considerable number of the came with three sets of interchangeable con­ members of the original Delta team are still figurations -- 3, 6, and 9 solids. The operational at both outfits. spacecraft managers, as experience clearly shows, are in these cases apt to "get there The Delta development program involved 12 fastest with the mostest" and pick the highest vehicles of the DM-19 configuration, 11 l of available payload... ' which were successful. No history is complete without the "firsts" In 1962, characteristically, the Delta first that the newspapers used to list in their stage was uprated (utilizing an Air Force "scorebox" when outerspace was young. Thor DM-21 first stage) and named Delta A. After changes in the vehicle control system The honor roll of these early satellite and a fairly extensive ground-qualification "firsts" for the Delta vehicle includes: program. Delta 13 and 14 were successfully 1) First passive communications sattelite launched in October 1962. Only two Delta A (ECHO I) configurations were ever launched. The (handwriting of the Delta was on the wall. 2) First international satellite (ARIEL) ( A long history of the state-of-the-art per­ 3) First privately owned satellite (TELSTAR) formance improvements had just begun. 4) First geosynchronous satellite (SYNCOM I) Delta B was improved by lengthening the 5) First equatorial geosynchronous satellite second stage propel!ant tanks by three feet (SYNCOM III) and changing the oxidizer from white inhib­ ited fuming nitric acid (WIFNA) to inhibited 6) First polar orbiter from ETR (TIROS I) red fuming nitric acid (IRFNA). It added 7) First commercial comsat (EARLY BIRD) roughly 100 Ibs. to a 200 n. mi. circular orbit payload capability. In today's numbers 8) First operational weather satellite it may look like a bag of peanuts, but let (ESSA I) us remember that Vanguard I (still in orbit) 9) First lunar orbiter without midcourse was a whole total of 3.25 Ibs. velocity correction (AIMP-E) Having weathered successfully the improve­ But more than the "firsts", three points ments of its first and second stages, it was evolve from the past Delta history: only logical that the Delta management, in its orderly one-two-three punch sequence, 1) The cumulative launch success ratios next incorporated a new third stage solid have remained in the 92% to 95% region 6-33 2) The probability of on-time liftoff has similar previous Delta mission. remained unbelievably high: 70% for a one second window Preliminary Mission Analysis (PMA). Today 90% for a five minute window the first step of the mission planning 3) Reimbursable missions have become a that is 'tailor-made 1 for a particular space­ mainstay of the Delta launch schedule. craft is the Preliminary Mission Analysis, published usually 8 months before the launch. PMA uses all mission requirements and S/C 3) MISSION PLANNING characteristics (weight, moments of inertia, etc.) in order to generate a trajectory se­ For the purposes of this paper the mission quence and profile. At this time the payload hardware coordination schedules are not capability is fixed within a few pounds. PMA discussed and only mission analysis docu­ also includes range safety and vehicle dis­ mentation is reviewed. persion analyses. Tables, probability dis­ tribution curves, and covariance matrices Spacecraft Restraints Manual. Whether a present predicted dispersions of all space­ mission falls into the class of the Delta craft injection conditions and classical vehicle capabilities, can be approximately orbital elements. A complete and detailed estimated from parametric performance curves trajectory printout is included in the PMA. maintained by Delta mission analysis engi­ neers and published in the Delta Spacecraft Detailed Test Objectives (DTP). Approximately Restraints Manuals (such as ref. 5).