I I SMALL PAYLOAD ACCOMMODATIONS (SPA) 1\ for the Family of Launch Vehicles I SS·88·60 2nd Annual AIAA!USU Conference on Small Satellites I September 19·21, 1988

I Gerald Broad - David K. Lynn I GOCLS GOSSD Abstract Historical Perspective The history of small, secondary payload ac­ In 1960, GD developed the Scientific Pas­ I commodations on early ATLAS boosters is senger Pod (SPP; Figures 1,2, and 3) for use reviewed. Design and flight operations con­ as low cost space research vehicles to take ad­ cepts for small payloads on current ATLAS vantage of unused payload or fuel capacity on I launch vehicles are presented and discussed. ATLAS flights. The pods were side-mounted ATLAS system capabilities are on the booster, separated, and flew a ballistic presented in terms of launch site integration trajectory for about 35 minutes. This flight I schedules and the excess performance which duration doubled the capability of sounding will be available to launch small payloads. and offered longer, higher flights for I the gathering and telemetering of data. The 'Introduction ' Commercial Launch Ser­ I vices, Inc. (GDCLS) is offering launches by the ATLAS Launch System on a commercial basis. The current offering consists of I and ATLAS II, IIA, and lIAS launch vehicles whose performance cover the I range of geo-synchronous transfer orbit (GTO) payload weights to nearly 7000 pounds. With an apparent increase in I demand for the launch of small payloads, CLS is considering reinstituting the 1960s General Dynamics program of launching small, secon­ I dary payloads with the ATLAS. The follow­ ing is a brief recap of the early ATLAS his­ tory of launching these payloads, an overview I of current design and operations concepts and concerns, and a discussion of their future on the ATLAS family of launch vehicles. Figure 1. Tandem SPPs Ready for a 1960s ATLAS I Launch. I SS-88-60

3018'...... ~

I Programmer I ...... - Electrical Subsystem Satellite ---H ExDeriment I Volume 8.1 cu. ft.

102' Payload I Section 8.1 cu. ft. I Adapter --+"'" 60' 151.5 in. I I ...... --r- Guidance Subsystem I

Figure 2. The Standard SPP Accommodated Canisterized Payloads. I

SPPs were designed in two sizes for widely different missions. The standard pod (Figure I 2) was designed for captive flight of small payloads (8.1 ft3 and 450 pounds). The large Ii pod (Figure 3) was designed to house and Attitude'--HI~ deploy a small satellite with a self-contained Control '----..... propulsion system (GD's OV-1 with its 300 lb Subsystem I payload and 800 lb propulsive stage). More than fifty SPPs were flown during the 1960s for the Air Force Office of Aerospace I Research, the Naval Research Laboratory, Figure 3. SPPs Also SUj:Jported,ProRulsive Payloads the Defense Atomic Support Agency, Nation­ (GD's OV:l Depicted). al Aeronautics and Space Administration, and The only SPP interface with the ATLAS was I the Advanced Research Projects Agency. its physical attachment. There were no I I I

SS-88-60 I electrical, guidance, nor telemetry interfaces. The small pods remained fixed to ATlAS or were separated pneumatically from the sup­ I port cradle at sustainer engine cut-off (SECO). The large pod remained attached to I the vehicle, the pod's hatch opened, and the propulsive payload jettisoned. The SPP's payloads then performed their mission, either I reentering the atmosphere or, in the case of the propulsive satellites, injecting into low I earth orbit (LEO). The SPPs provided battery power, signal con­ ditioning equipment, commutators, subcarrier I oscillators, an FM/FM transmitter, RF and pod-separation switches, and two antennas. ATLAS Booster I The pod's controller sensed SECO then sup­ plied an output signal to eject the passenger pod from the booster. It also provided step or I pulse outputs to operate payload equipment.

SPA eODemts FtgUl'e 4. Dual OV·1s on an early Atlas booster. I Building upon our early experience with small, secondary payloads on the SPP During the 1960s, ATlAS flew multiple small program and utilizing the current excess per­ payloads as shown in Figure 4. Today's I formance available from the ATLAS family ATlAS is available for the launch of multiple of launch vehicles, CLS is studying concepts payloads (with or without the use of our Cen­ for Small Payload Accommodations (SPA) as taur upper stage). I a follow-on to our history of low cost, assured access to space. FtgUl'e 5. A Typical RV Adapted for Lateral Release . ...--. , //- .... "-, ",,' I / /' " \ /,: ATLAS-Mounted 1/ \..(' I: I ' \ I I \ \ Similar to the 1960s SPP, the ATlAS­ I ! , \ ~ i ;!~ .- I mounted SPA pods can be available in two 'I ---- - _ ... ". , . iCi=~= _... : A'TI..AS ( , '1( Ii " .It' sizes, short and long, for payload canister(s) \1' , I '"Ji 11' ,il;~" B, ooster . , I ". l' l.. I I and payloads with integral propulsive stages. \ " ~~J/ !~rue Tank Each pod will offer power, command se­ \\ \• ...... + i-~J.. ./ I 1""'\"~'1~. \\ I I' I, " quencing, and telemetry services. All SPA 1 '--:'-1" , ~ ...... I "" l~ pods will follow the fully autonomous " ...... / I regimen of the original SPP. SPA payload customers will be offered the option of I providing their own integrated pods utilizing this same guideline. I I I' SS·88·60 I I Payload Adapte Spacer Adapter Modul SPAPayloa 14ft. PLF I I I I: I Prime Payload l07.0in. Payload Adapter 1-1 SPA Payload I lOO.Oin. Spacer

77.0 in. Equipment I Module I I F'pe 6. Spacer Adapter Concept for -Mounted SPA Payloads.

Another ATlAS-mounted SPA design con· fairing (PLF) will adequately protect these I cept is to provide compatiblity with domestic payloads during the launch and ascent en­ or foreign recoverable vehicles (RVs; Figure vironments. Similar to the ATlAS-mounted 5). Such an RV would be adapted for lateral payloads, all Centaur-mounted payloads will I release and could be encapsulated in an utilize isolated power, command, and aerodynamic fairing. The recovery of the RV telemetry services. I and its payload would be the responsibility of the RV contractor. SPA payloads investigating the LEO regime must be separated from the Centaur during I the park orbit coast. Payloads interested in Centaur-MQunted GTO orbits (with the potential of recovery by In addition to the original 1960s SPP side­ retro-powered RVs) or geosynchronous or­ I mount concept, small, secondary payloads bits (with an integral propulsion stage) will be may be mounted on the ATlAS upper stage constrained to remain attached until after I (Centaur; Figure 6) and offered a variety of prime payload deployment, possibly even high energy orbits to captive, free-flying, and after the Centaur's Collision and Contamina­ propulsive payloads. The ATIAS payload tion Avoidance Maneuver (CCAM). I I I

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Prime Payload Considerations (booster and upper stage) will satisfy the I In the highly competitive world of commer­ prime payload requirements then accom­ cial launch services, CLS has accepted the modate the requirements of the SPA I responsibility for on-schedule mission suc- payloads. Additionally, SPA propulsive cess. Consequently, CLS's prime objective on modules must be inhibited from ignition in every flight is to ensure on-schedule prime the vicinity of the prime payload. I payload delivery. Once a SPA payload has been accepted, CLS CLS will integrate the flight requests of SPA will be responsible for the integration of the I payloads on commercial ATLAS missions on payload with the GD-provided module as well a conservative non-interference (technical as the flight manifesting, interface design, and and schedule) basis. SPA manifesting will be launch operations. The SPA payload cus­ I based on excess mission performance, com­ tomer will be responsible for all payload ac­ patibility of payload requirments with the tivities in support of the integration analysis, I prime payload's ATLAS mission (mission design, and verification and meeting the planning and flight operations) and SPA schedule requirements of the prime payload. resources (optional services), as well as the I) ability of the SPA payload customer's to meet Typical integration activities are expected to the integration and launch schedule of the average nearly two years (Figure 8). This I primary payload. time will be spent ensuring the compatibility of the SPA payload with the prime payload The assessment of non-interference will in- mission and ATLAS launch system to the elude impacts on the launch, ascent, and on­ satisfaction of both CLS and Range Safety. I, . orbit environments of the prime payload. Or­ Figures 9 and 10 outline the SPA payload's bital operations of the launch vehiele system launch site processing time line. I

Months Before/After Launch I Milestones 24 123122121120 119118 117116 115114 113112 111 110 I 91 81 71 6 15 14 P 12 11 10Jl 1 Payload Int,o ~ (PIL Data Pkg.) I PIP ~raft 6Final leo 6Draft Ninal

Optional Svc Analyse. I I Design I I Safety Reviews 6 6 6 I Match Mate 6 Integ,atlon L::J (detall sched.) I launch 6 Post Fit Anal. c::

I Figure 8. A Typical SPA Integration Schedule. I SS-88-60 I

SPAf.light F'li2ht Status SPA Readiness & Iiistallation Verification INSTALLATION I Review Briefing & Acceptance Installation & Checkout Complete LAUNCH I Working Days (before/after SPA Inatallation) 30 20 10 0 0 I Verification of: Verification of: ~Prime Payload interfaces GSE Installation Configurations Procedures I Safety Rqmta Special Support Weighta&cg Schedule for Cleanliness Installation Documentation I

NOTE: Payloads should be capable of on-pad holds of up to 60 days without access (electrical umbilical for monitoring and battery charging is permitted). I Figure 9 ATLAS Booster-Mounted Launch Site Integration Schedule. I I I

SPA SPA Flight FlililitStatus INSTALLATION Readiness & Installation Verification I Review BriefIng & Acceptance Installation LAUNCH & Checkout Complete I -L----_..I..-____.l....- ___--L-..JI...-_-I( Working Days (before/ '1--__--' \. after SPA installation) 30 20 10 o 2 3~38 I Verification of: Verification of: Interfaces GSE Prime Payload Configurations Procedures Inatallation Safety Rqmts Special Support I Weights&cg Schedule for Cleanliness Installation Documentation I

NOTE: Payloads should be capable of on-pad holds of up to 60 days without access (electrical umbilical for monitoring and battery charging is permitted). I Figure 10. Centaur-Mounted Launch Site Integration Schedule. I I I I SS-88-60

CENTAUR CENTAUR SECOND ORIENT & FIRST BURN 1ST BURN PARKING CENWJR SEPARATE RfTROMANEUVER I PRESTART EVENTS PHASE ORBIT PHASE BURN SPACECRAFT • PROPEWNT SPACECRAfT PHASE 8I.O\VDOWII CONTINUES AlUSICENWlR MISSION SEPARATION PHASE I I'" '.1 , ATLAS _??" .qCI2' r--f-/~o-O!_!:-~- -fJ-(T_ SUSTAINER -::.-,.:0 \ -0-_ I PHASE ...~.~... MECO 2 - ..... (J...... I JtP' MES 2 END CENTAUR ".1'\.. MECO 1 (MAIN ENGINE CUlOFF) MISSION I .~/J.: NOSE FAIRING ~ MES 1 (MAIN ENGINE START) ~. "" JmlSON CHILLDOWN I 'l INSULATION ATLAS/CENTAUR SEPARATION ~---,~,_ PANELS JErnSQN (ATLAS q SECONECO (SUSTAINER ENGINE CUlOFF/ =EII '~l" BOOSTER VERNIER ENGINE CUlOFf) I PHASE g \ SECTION SECO Li JEmSDN (BOOSTER ENGINE CUlOFF) '---- SRM MOTOR I JEmSON (ATLAS liAS) I FJgUl'e 7. Overview of a Typical GTO Mission. Table 1. REPRESENTATIVE ATLAS I AND SPA Mission Orbits ATLAS WIIA GTO MISSION TIMELINES. I SPA mission orbits are defined by the ATIAS mission profile of the prime payload (Figure Time (sec) Time (sec) I 7). ATIAS lower-stage mounted payloads Event AUAS I ATLAS IIIIIA are separated with a suborbital trajectory (see Liftoff 0.0 0.0 Table 1 for typical timelines). Constraints on BECO (5.5g) 156.0 171.2 I propulsive payloads would key SPA ignition Jettison Boost. Pkg 159.1 174.3 to payload fairing jettison or after MES-1 Jettison Insul. Panels 181.0 N/A (near lower stage apogee). Jettison PLF 227.3 223.4 I SECO 264.3 278.6 Centaur-mounted SPA payloads will normally {Deploy SPA 265-266 279-280} have a choice between LEO and GTO for ATIAS staging 266.3 280.6 I their separation (fixed payloads, of course, Centaur MES-1 276.8 291.1 are relegated to remain with Centaur to Centaur MECO-1 610.0 677.1 GTO). The Centaur's LEO park orbit is {Deploy SPA 615-1358 681-1413} I nominally 80 + nm (perigee) by less than 400 Centaur MES-2 1478.5 1533.0 nm (apogee) and inclined at 28.5 deg. Injec­ Centaur MECO-2 1555.6 1632.0 I tion into GTO normally occurs at the first Prime Payload equatorial crossing and results in an apogee Separation Attitude 1557.6 1643.0 of 19,323 nm at about 27.25 deg. Some prime Prime Payload Sep. 1690.6 1767.0 I payloads may require that the inclination be CCAM 1705.6 1782.0 reduced and a super-synchronous transfer {Deploy SPA any time up to I orbit be provided. Centaur deactivation} I,

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ATLAS Fromms The typical GTO mission will provide a park With its beginnings as an intercontinental bal· orbit coast of about 13 minutes prior to Cen­ I listic missile, the ATlAS heritage spans 30 + taur restart for the GTO injection burn. years in service to the free world's space programs. The ATlAS launched the first Figure 12 identifies the current vehicles in the I U.S. manned orbital space flight. Coupled ATIAS family, their programmatic status, with the Centaur, the world's first liquid and GTO performance capability. The I hydrogen/ stage, the ATIASI ATIAS I is the first vehicle in the continuing Centaur vehicle has provided launch services evolution of the long line of ATIAS vehicles to 37 communications spacecraft (GTO), 9 (492 launches since 1957) and is the first I planetary and 7 lunar missions (earth escape), ATlAS to offer a large (14 ft. diameter) and 14 payloads to (LEO). metal payload fairing. Increased performance and higher reliability are obtained with the I The current ATIAS consists of a stage-and-a­ steps to the ATlAS II, 'ITA, and lIAS. (It half booster vehicle and the Centaur upper should be noted that the U.S. Air Force stage (Figure 11). The vehicle launches from selected the A1LAS IT for the Medium I Complex 36B at Cape Canaveral Air Force Launch Vehicle IT (MLV II) program.) Station, Florida (CCAFS) and accelerates to Figure 13 shows the potential of these 5.5g before separation of the two booster en­ vehicles for carrying multiple SPA payloads of I gines and their thrust structure. ATlAS different sizes and types as a function of flight continues under power of the sustainer prime payload mass and ATIAS family mem­ I engine. Centaur's two main engines then in­ ber selected for launch by CLS and the prime ject the Centaur and payload into park orbit. payload customer. I, ATLAS Upper Stap (Centautl Payload I ATLAS Lower Stage: Spacerrrruss & Payload .&uaJJI.t:C::l~1IIMiI' ,...--_. Booster Engines Engines---,. I Sustainer Engine Oxydizer I (sll'&\IJ'.nt.g) 1 I I I I Figure 11. ATLAS Configuration. I I

I SS-88-60 ATLAS I ATLAS II ATLAS IIA ATlAS liAS I I I I I I PAYLOAD TOGTO I 11 FT PLF 2335 KG (5,150 Le) 2765 KG (6,100 Le) 2900 KG (6,400 LS) 3158 KG (6965 LS) 14 FT PLF 2245 KG (4,950 Le) 2675 KG (5,900 LB) 2810 KG (6,200 LS) 3068 KG (6765 LS)

IN DEVELOPMENT STATUS IN PRODUCTION PLANNED I PRODUCTION I 14 FT PLF SHOWN (11 FT PLF OPTIONAL)

I Figure 12. The ATLAS Family of Launch Vehicles. Commercial ATIAS launches are from Com­ family of launch vehicles and commercial I plex 36B at a rate of four per year (with a launch services. surge capability to five ). I ATLAS launch services can include Summaa provisions for the small payload community. The early days of space exploration may be I With our broad range of experience, we can behind us but we are finding that the need for accommodate small payloads as fixed and jet­ low cost access to space is greater than ever. tisoned payloads, single and multiple From one-time experiments to constellations I payloads, and as secondary or primary of small spacecraft, the need for such launch payloads. services appears to be expanding. General Dynamics' Commercial Launch Services, Inc. I We recommend the standardization of simple is recognizing this need and is in the process interfaces and will support their definition to of accommodating you, the small payload I assure early incorporation into the ATLAS community. I I GENERAL DYNAMICS Space Systems Division I I

PRIME I PAYlOAD MASS (pounds to GTO) I I I EXCESS PERFORMANCE (pounds) ~ f i 1 (max) 450# SPA Payload Ballistic Payload H-++-I------~ I Sub-orbital PropuhWa 1--11+-\1__ 1+12 __ ....3 j __11-(m_ax_) ______---=1""'150;;:#::;:S:::s:PA SPAs Payload I I I I Payload I ) j2 ~ "', (max) Jettisoned 1-_____+-I-I---1I_+-I ______~2lIO:::::#'7:;S~PA LEO SPAs ~~ 1 1 I I ~

Flxedl i? I GTO SPAs Jett~ned t--______+-- ___+-11 ______~250;;:#::;:S:::s:~ Payload 1 Payloed

NUMBER::l OF AVERAGE SPA PAYLOADS I

Figure 13. SPA Capabilities are Dependent Upon Launch Vehicle and Prime Payload Mission Mass. I

We welcome the opportunity to discuss ATI.AS's potential application to your I program. Please direct any requests for information to:

Mr. Gerald Broad I Mission Development General Dynamics Commercial Launch Services I P. O. Box 85911 San Diego, California 92138-5911 (619) 496-4003 I GENERAL DYNAMICS Commercial Launch Services, Inc. I I