22 nd Annual Small Conference on Small Satellites

Transcription

1 22 nd Annual Small Conference on Small Satellites The Stellar-J A Partially Reusable Horizontal Take-off Launch Vehicle For Small Satellite Missions Wes Kelly, Paul Royall El Camino Real Suite 210A Houston, TX (281) / 1

2 ELEVATOR PRESENTATION The Small Satellite User Community needs A cheap, reliable, launch system that can: Turn around fast, grow with user needs, Cultivate capabilities for the future such as: Rendezvous & Return Cargo The size of the community, both domestic and foreign is large: - Small Companies - Civil & Military Offices - Private Research Institutes - Universities & Related Research Consortia It has a backlog of hundreds of satellites in a $20K/lbm payload market. Our Approach: Horizontal take and landing first stage with wings and jet engines. Rocket burn from airline cruise to typical booster rocket staging. Concept scales from 35 to 350 tons. Capable of operating at conventional airfields up to jumbo jet facilities. Sorry to interrupt, sir, but this is my floor. 2

3 At the AIAA* Space 2007 convention in Long Beach, CA, in September CEO & President Dr. William Ballhaus of the Aerospace Corporation gave the keynote 1 address. Reviewing launch system development since Sputnik & the direction the US should take for the next 50 years, Ballhaus recommended: A partially reusable launch vehicle, concentrating reusability in the 1st stage; A vehicle with wings, air-breathing jets as well as rocket engines; It should fly frequently, respond rapidly and be able to deploy different upper stages (expendable or reusable) allowing for flexible operations. Dr. Ballhaus was unaware that had been working to develop such a vehicle over the past decade The Stellar-J >> 3

4 Current programmatic references to hybrid launch vehicles and reusable first stages assume vertical launch and horizontal landing. Historically this has not always been the case. Though VTO vs. HTO design controversies are multi-faceted issues, we note that most Small Satellite Conference participants arrived in Logan via HTO craft due to - proven operating capabilities, - frequent launch opportunities, - convenient infrastructure Compared to the VTO Alternative. From Air-Jet Propulsion Systems by P. G. Kappus, In The Handbook of Astronautical Engineering, Edited by Heinz H. Koelle, New York, 1961: 4

5 Shuttle derivative & upgrade studies of the 80s & 90s Included Liquid Rocket Boosters to replace existing Solid Rocket Boosters. Beside expendable LRBs In late 1990s, work included Liquid Fly-Back Boosters with wings and reusable rocket engines, cruising back to launch site in final sub-sonic flight leg on jet engine power. Booster power plants featured newly available long-life, high performance kerosene-lox staged combustion engines. RD-180 and several alternates. were rated for numerous starts. Liquid Fly-Back Booster concepts, systems and hardware Re-arranged and re-scaled result in the HTO reusable first stage (RFS) described. But the launch system need not weigh 2000 tons at liftoff. 5

6 The Stellar-J employs horizontal take-off and landing from conventional airfields Rocket transitions occurs at subsonic stratospheric cruise. Vehicle climbs to rocket shutdown at ~150,000 feet & hypersonic velocity. Releasing upper stages carrying payloads to orbit, The reusable first stage returns to land & refurbishment. High α Re-entry Horizontal Landing Upper Stage Options Upper Stage Launch Time after takeoff (seconds) Altitude (n. mi.) Climb-Out From HTO The concept scales for configurations from tons take-off weight based on Available high performance reusable engines. Market research shows the opportunity for the smallest initial investment & earliest returns: the small satellite market, payloads ~ 100-lbs to low earth orbit (LEO). A standing backlog of ~500 small payloads has remained for decades awaiting launch opportunities with limited slots and market costs of $20,000 per payload pound. 6

7 Stellar-J Mission Develop space launch vehicles providing significantly lower cost and frequent access to space for commercial and government customers. Triton s long term goals include the development of 4 vehicle types tailored to satellite size. The series of vehicles are called Stellar-J. Stellar-J Vehicle Type Weight to LEO Small Satellite Launch Vehicle(SSLV) <250 lbs Stellar-J-35 <1000 lbs Stellar-J-70 <2000 lbs Stellar-J-350 <20,000 lbs The current small satellite market is underserved due to high launch costs and availability of launch opportunities. Launch options include: - high cost dedicated launches at $20K/payload pound or - hitch-hiker assignment on large vehicle dedicated to primary payload. Availability of a small satellite launch systems with launch cost under $5M will capture a significant share of the estimated 500 satellite backlog. And more importantly, will stimulate small satellite development for research, communications, observation, and earth imaging. Stellar-J Concept on the Cover of AIAA Horizons 7

8 Stellar-J Launch System: Horizontal take-off and landing 1st stage with wings & air-breathing engines Climbs to stratospheric subsonic cruise before igniting Rocket engines and ascent to hypersonic high altitude burn-out. Turbofan flight portion removes ~2500 fps from the rocket equation ( 1 & 2) Requirement of ~30,000 fps ideal velocity to obtain orbital flight. Recovering long-lived high- performance rocket engines & 1 st stage elements allows: - Order of magnitude reduction in first stage recurring costs ( => aircraft costs) - Quick turn-around and frequent access to flight for payloads - Self-ferrying capabilities and operation to & from air fields with facilities - Flexible azimuth and inclination adjustments to launch windows - Modular vehicle design adaptable to several markets (includes suborbital tourism). 1. Velocity Losses with Altitude: Altitude (ft) ~(2 g h) 0.5 Velocity (fps) , ,000 1, ,000 < 4, Azimuth Velocity Contributed by Jet Flight M at altitude < 1000-fps 8

9 The Small Satellite Market: Investors Want to Know How Many Small Satellites Are Out There? The oil industry has estimates of petroleum reserves; A theory can be developed as well for Small Satellites: A renewable resource influenced by accessibility to space. Our first exposure to Small Satellites: an undergraduate design project For an Ozone Monitoring Satellite designed for a Scout Booster. (U. of Mich. 1973) It was not launched, but later similar satellites were. Note: the satellite addressed one of an ever expanding applications list. The process has been going on for over 35 years at many institutions: Business, research, education, civil government agencies, defense, Domestic and overseas 22 Small Satellite Conferences are an Indicator. Small Sat Reserve Estimates (yesterday, today and tomorrow) should consider - What is concept maturity, funding and resources? - If concept has remained grounded for a long time, why is it stalled? - Has team dispersed to other assignments; can effort renew? Finally, the Influence of Available Launch Technology: - How many projects become feasible if launch access and/or cost improve? A figure of Merit: a 500 satellite backlog, average weight 175lbs, $20K/lb delivery fee: $1.75 billion backlog. An Axiom: Small Satellites continue to be conceived as existing ones launch or fade from view. Even if correct, reserve estimates are not final. 9

10 Triton s Market Entry Our market research shows the opportunity for the smallest initial investment and earliest returns is the small satellite market, payloads of <250-lbs to low earth orbit (LEO). A standing backlog of ~500 small payloads (less than 1000 lbs) has remained for decades awaiting launch opportunities with limited slots and market costs of $20,000 per payload pound. 50% of the 500 backlogged satellites weigh less than 250 lbs. Market Potential exceeding $875M (175lb average satellite weight) Triton has designed the Stellar-J SSLV to serve this market - Integrates existing/proven technologies - Gulfstream III/IV platform for modifications - Aerojet NK-31/39 derivative rocket engines Development Cost - $93M 10

11 Small Satellite Launch Vehicle Demonstrator SSLV Targets ~250 lb Satellite payloads Existing Systems: Controls Avionics Flight Systems Air Breathing Engines Environmental Control Aerojet NK-39 Flight Proven LOX/Kerosene Engine 11

12 Stellar-J 35-ton Vehicle (Size of Gulfstream III) -Designed for 1000-lb Satellite Delivery -Winged 1st Stage Achieves hypersonic burn-out at ~30-nmi. altitude -Addresses satellite attached payloads or space tourism market Initial Commercial Markets & Trades Or - Small Satellite Launches <1000-lbs. ~500 in backlog or development Market $20K/lb Payload Payload separates except in abort. - Suborbital Tourist Module Uncertain demand Market prices ~$200K/passenger Payload remains attached - save for abort. 12

13 Satellite Market In 2004 Triton Identified 8 Primary Markets for 4 Vehicle Systems Vehicle Types and Configurations LEO Satellite Payloads (lbs): ,000 2, ,000 - A B C D Mission Model for Revenue Demo 35-ton 70-ton 350-ton + Orbiter 1. Sounding Rockets x x 2. Sub-Orbital Tourism? x x 3. Micro-Satellites X X x 4. LEO Satellite Constellations X X x 5. LEO Space Platforms x 6. Rendezvous Payloads x x x x 7. Sortie and Return Payloads x x x x 8. Rescue Standby x x x x Primary Markets Missions (1-8 and Subsets) Graded on Scale of 1 5 with 8 Parameters (Red X: High return on low initial investment ) 1. Market Maturity 5. Mission Procedural Complexity 2. Market Demand 6. Mission Hardware Complexity 3.Price Margin over Mission Cost 7. Regulatory Barriers 4.Potential Volume 8. National Economic &/ Strategic Security 13

14 Market Research For 21 years Utah State University has hosted the Small Satellites Conference A 2007 Summary: 62 exhibitors included - satellite & component vendors, satellite users, - large and small aerospace companies, - university, government & private research units domestic and foreign - 78 presented papers represented with 137 cited organizational units Cicero Spacecraft -Broad Reach Engineering reported on CICERO: a constellation of kg satellites. CICERO will perform radio occultation measurements of earth s atmosphere for weather and hurricane prediction. Discussions with the vendor about this 3rd generation project indicates: Hardware is in assembly, but no launcher is signed on for deployments over the next decade. - World small satellite leader Surrey Satellite Center (UK) described several similar prospective programs. About a dozen universities reported on individual satellite programs Annual satellite launch rates (monitored by Futron Research) do not match systems introduced. Satellite backlogs (~500) with introduction of new satellite concepts would go even higher. But some waiting for launch slots or low cost opportunities will eventually fade away; Research and development teams, organizations and sponsors will eventually move on -Unless more rapid, lower cost means of satellite launch are made available. The need for such a launch system is a recurring conference theme. 14

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16 Technology Impacts Extrapolating mass fractions (λs) for HTO launch from existing aircraft is difficult: High λ is not considered a conventional aircraft premium. With improved SFC, fuel allocations diminish rather than increase. The λ of the B-47 from 50+ years ago compares favorably with current values - save long endurance RPVs or globe circling competition aircraft. To obtain λ of 0.6 to 0.7 for a hypersonic craft, expect hybrid structures of ballistic rocket conventions (tank-intertank) plus ring-stringer aircraft forms. Air-Breathing Engines: a major HTO 1 st stage structural element for which technology advances will be a significant consideration. But noise abatement, thrust reversal and long range cruise optimization efforts all digress from HTO jet installation requirements. For the short duration climb to stratospheric ignition, moderate by-pass ratio turbofans with high thrust to installed weight (T/W>5) would be desirable. Some military engines here fare well, but unit sizes are limited. Engines now considered obsolescent for commercial mid-size jets serve better for larger Stellar-J configurations. Protection of air-breathing engines in ascent is much the same for HTO and VTO, but HTO provides hot re-start for return. Pulse Detonation Engine research provides promising performance gains though even analytical characteristics now remain vague. A likely benefit is reducing installed engine weight, but effects on volume, inlet cross section, placement and cg are undetermined. Impact on ascent is greater for HTO than VTO. 16

17 High velocity re-entry at high angle α (35-45 o ) argues against payloads Or tourist modules attached below wings and TPS 17

18 Technology Impacts -2 Materials & Structures: With a baseline Al-2219 structures, advances in high temperature alloys and carbon fiber materials could assist in bringing in the targeted mass fractions. Previous fly-back booster studies show that TPS requirements are only small fractions of Shuttle Orbiter s, based on time and velocity heat loads. In cases where titanium and aluminum were matched, the attachment of TPS to the frame metals with adhesives created a critical temperature link that limited Ti effectiveness due to adhesive temperature limits rather than inherent Ti high temperature strength. Higher yield temperatures in new aluminum alloys is a basis for re-examining such trades. Flight Control: HTO stability and control relies more on aircraft characteristics than the VTO does in ascent - to stratosphere. Classical control methods can define a preliminary system. We note need for repeated update of constant coefficients with sets of I-loads for standard sub-sonic flight, transition to rocket flight, reducing aerodynamic control effectiveness, then total reliance on pulsed and gimbaled thrust, re-entry transition back to aerodynamic controls and then abort cases. It is difficult to provide quantitative assessment of the control issue on upper stage weight limits, but it is clear that finesse in this design issue is critical for achieving full capabilities. 18

19 Stellar-J Flight Control 19

20 Stellar-J 35-ton and SSLV Based on 135 and 90-sec Burns Stellar-J < 35-ton HTO < 6-ton Upper Stage(s) & Payload Isp: 1st Stage, 300; 2nd 320-secs. Payload Results Lambda: Stage: Stage: Demonstrator (<3600-lbs) ~100-lbs 20

21 Revisionist Space History and Perspective: For several decades, beside Shuttle, Soyuz spacecraft were the only other way for crews to reach LEO. Soyuz and the Progress cargo craft ride atop ELVs of <350 tons lift-off mass, typical of a commercial jumbojet. Serviceable airfields in the US for 747s provide a vast transport grid, but few places worldwide are available for launch of 350-ton ELV s. For over 40 years commercial turbofan powered craft routinely cruise in subsonic flight at ~35K-ft, a flight mode allowing azimuth and launch window adjustments impossible for ground launched ballistic craft; a mode that also significantly reduces total ideal velocity needs of rocket ascents. Flight-testing for both the X-15 and SpaceShipOne proceeded incrementally through flight envelopes inaccessible or available at high cost only briefly for vertically launched programs. Other airfield based rocket planes already exist, have been tested or are planned: USAF test pilots trained for the X-15 and other craft with a rocket equipped (NF-104) jet through the 60s until 1971, routinely exceeding 100,000-ft altitudes. Pegasus, the X-15 and SpaceShipOne are all dropped from carriers; XCOR s kit plane takes off from airfields under rocket power. Growth versions (e.g., Lynx) are in development. However, decades have been devoted to develop and field costly combined cycle rocket engine-turbojets; another decade is likely. So, why our approach? 21

22 Revisionist Space History and Perspective (2): Launching the Pegasus from an L-1011 delivers only half-ton payloads to orbit. Replacing the carrier craft with a genuine first stage (Stellar-J) increases the yield by an order of magnitude. Rocket ignition on the runway hardly expands aircraft performance envelopes; mostly its capability to climb. The Stellar-J employs turbofans where efficient equivalent ISP >5000 secs, then shifts to rocket power, converting a carrier craft to a dedicated stage, improving payload yield vs. takeoff weight, but retaining operability. And although some rocket planes meet one commercial criterion carrying passengers - It is to the neglect of the cargo satellites, launched from upper stages released at booster burnout. Since both turbofans and rockets engines are in fact COTS, development is radically less costly and complex than scramjets, etc. and ascent loads are more benign. In other words, separate rocket and jet engines work as well or better than combined cycle engines at much less cost. Additionally, existing staged combustion kerosene engines offer high thrust to installed weight; their chamber pressures result in compact designs including nozzles more easily integrated into an aircraft s tail section. 22

23 The Road Ahead: Test bed aircraft, the development key demonstrating Stellar-J technologies: 1. Rocket ignition and pull up from horizontal subsonic stratospheric cruise after jet powered takeoff; 2. Rocket shutdown at high altitude and Mach number, upper stage separation and first stage descent to glide-back or powered landing. 3. Successive executions demonstrating reusability, turn-around capability and increasing performance (including aborted mission procedures). 4. Provide subscale orbital bus and payload demonstration. Some procedure elements have seen separate demonstration, but no combined execution supporting orbital cargo delivery as yet. Issues of particular interest are 1. First stage mass fractions 2. Moment management, 3. Aero-thermodynamics, 4. Jet restart, 5. GN&C (all phases), 6. Emergency landings with upper stages 7. Remaining critical paths (e.g., upper stages) after 1 st stage turn-around. Modest investigations compared to SSTO or scramjet RDT&E. 23

24 To Open the Flood Gates on a Small Satellite Backlog Stellar-J as a System Must Address the Following: - Increase Launch Opportunities and Launch Rates - Reduce Individual Launch Costs - Reduce Flight Preparation Time Elements of Approach Reusable First Stage: HTOL with reusable rocket engines Element approaches aircraft operation costs Limited by rocket engine lifetime (10, 20 or TBD flights). Ground Facilities: Airfields adjacent to launch ranges with clear azimuths, LOX facilities, stage integration facilities. Upper Stage Integration: Candidate upper stages (1 or 2) certified for integration, ascent and separation. Payload Buses: Adapted to Stellar-J, derived from Small Sat heritage (e.g., approaches documented in Small Sat Conferences) Payload Accommodations: Facility and airfield handoff to booster. With RFS ( or small fleet), critical path moves to upper stages; With stockpiled upper stages, bottleneck moves to payload bus & integration. Solution of the final bottleneck will require coordination with payload community. 24

25 BACK UP CHARTS FOLLOW 25

26 Stellar-J Value Proposition The Best Solution to industry s needs for economical & frequent access to space; Addresses immediate small satellite backlog due to costly infrequent launch opportunities VIA 1. Reliability: Current proven technology; winged flight under jet power with HTOL to stratospheric altitude & subsonic speed before rocket engines ignite; Rocket engines proven with 200,000 seconds test time and lifetimes of dozens of starts. 2. Low Cost: Uses conventional propellants & operates from runways vs. KSC launch pads; Retrieves high value propulsion with 1 st stage for repeated use. 3. Flexibility: Canister approach to upper stages / modules allows wide array of missions; launch from airfield(s) allows extended launch windows, landing sites down-range or return to take-off site. 4. Rapid Re-Flight: Airfield operations eliminate 1 st stage as bottleneck; quick turn-around. 5. Speed to Market: Brings reusable launch benefits at lowest development cost, shortest time; existing expendable systems/proposals add cost, reduce flight frequency & subject to unrecoverable flight aborts. 26

27 Stellar-J SSLV Financial Projection 1 st Production SSLV, Operational in 2012 Stellar-J Profit/Loss Prediction Stellar-J SSLV Development Cost $35 $23 $11 $9 Operations Cost $48 $48 $52 $56 $54 $57 Sales $0 $0 $0 $0 $105 $109 $117 $125 $121 $129 Profit/(Loss) ($35) ($23) ($11) ($9) $56 $60 $65 $69 $67 $71 Cum ($35) ($58) ($69) ($78) ($22) $38 $102 $171 $238 $309 Millions of Dollars Starting 2 nd SSLV in 2012 Operational in 2014 generates additional revenue stream 2nd SSLV Development Cost $21 $12 Operations Cost $48 $48 $52 $56 Sales $105 $109 $117 $125 Profit/(Loss) ($21) ($12) $56 $60 $65 $69 Cum ($21) ($33) $23 $83 $147 $216 Costs/Flight Recurring Operations Upper Stages Rocket Engine Amortization Total Operating $0.536M $1.16M $0.1M $1.796M Operating Assumptions Rocket Engine Life 20 Flights Airframe Life 300 Flights 27

28 From studies to date: Stellar-J is scalable over liftoff weights of tons Orbital payload deliveries of 0.5 to 15 tons, depending on upper stage characteristics. Lower liftoff weights and dimensions resemble those of a Gulfstream III with delta wings. The upper weight bound typifies jumbo jets such as 747 s, This is also the liftoff weight of Progress or Soyuz expendable launch vehicles. The Stellar-J 350 targets services similar or better than Soyuz/Progress employing conventional aviation facilities and reusable hardware components. 28

29 Triton Systems Stellar-J Functions like Soyuz or Progress: same lift-off weight, but reusable like a 350-ton jumbo-jet. - Winged jet engine airfield take-off - First stage lands at same or alternate airfield after rocket burn - Array of upper stages & payloads. For initial commercial markets 35-ton Stellar J Size of Gulfstream 3 - Small satellite launches <1000-lbs. ( ~500 in backlog or development) - Or suborbital tourist module ( according to market demand) 29

30 To Obtain Inclination and Ascending Node Targets Dog legs with switch backs to the ascent ignition target Stellar-J improves over the limited azimuth windows provided by vertical launch from the ground. Example 1: Change Inclination 1 o Beyond Ballistic Launch Window Dog leg maneuvers performed prior to rocket ignition, Exploit jet engine high fuel efficiency. VTO can employ yaw steering in rocket ascent, At low efficiency save for ascending node adjustment in nearly due east ascent. Ballistic VTO: 700 fps Change in Orbit ΔV Stellar-J HTO: Cruise north 60- nmi, then turn east during climb out to rocket ignition Or use airfield further north. Scramjet or ramjet VTOs could improve over ballistic rockets, but hypersonic air-breathing RDT&E far exceeds Stellar-J up front investment. Development costs for separate rockets & jets Far lower than combined cycle systems and the latter Yet to prove they lower mass or increased performance. A Foot Note: Turbojets could delay rocket ignition until supersonic speed after emergence on lowered drag coefficient plateau past transonic peak Worth investigating, but neither an essential element nor an assured benefit of jet and rocket combination. 30

31 ISS at Close of STS-118 mission over Mediterranean & Southern Italy, 19 Aug Example 2: Yaw Steering & Ascending Node Control for Rendezvous (When you have to have it there the next day) Stellar-J HTO: Steer and then turn azimuth heading on jet climb-out. Ballistic VTO: Yaw steer in rocket ascent [Effectiveness lowers with sin(az)] - Or wait until next day s window. ISS is NOT a Small Satellite, but Small Satellites and spacecraft Could have Rendezvous, Docking and Return requirements with it and other platforms. 31

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33 Despite nominal mass fraction differences, the first stage weights of the two systems are very close, but the lower λ also allows for provision for larger wings, jets, landing and landing gear. Due to lift off considerations, the rocket engines and thrust structure on the HTO are relatively smaller. In table on slide 8, constraints on upper stage & payloads are imposed on both HTO and VTO. For trial values, total weights of 500,000-lbs and 400,000 result respectively. HTO limit reflects Stellar-J design and simulation experience based on moment arms, cg and cp. When aborted mission considerations are included (e.g., forced landing with payload or upper stage), we note that HTO is at advantage over VTO for the reasons it is considered at disadvantage in other studies. 33

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35 Performance Envelope Analysis: Altitude, Q, Velocity, Mach VTO Max Q Modulated by Rocket Throttle VTO (T/W)o Determined by Pad Clearance Early Max Q on HTO Alleviated with Jet Throttle Secondary Max Q No Rocket Throttle Required HTO (T/W) 0 Lower Different Engine Out Criteria See Additional Performance Envelope Charts 35

36 Ram/Scram Jet Hypersonic RFS Reside in High q-dot Regions Low Mach Rocket Transition Provides Low q-dot Quick Transit 36