I I SMALL PAYLOAD ACCOMMODATIONS (SPA) 1\ for the ATLAS 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 launch vehicle 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. rockets and offered longer, higher flights for I the gathering and telemetering of data. The 'Introduction General Dynamics' 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 ATLAS 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 Centaur-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 I SS-88-60 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).