Expandable launchers Example of Ariane 5, European workhorse

1. Expandable launchers Example of Ariane 5, European workhorse Rocket Propulsion course Royal Institute of Technology, Stockholm H. LAPORTE - WEYWADA May 2006

2. Introduction to Space transportation activity • Main driver for launcher conception • Ariane 5 Launch System description • Photos : ESA, CNES, Arinanespace, EADS, SNECMA

3. Introduction to Space Transportation activity • Main driver for launcher conception • Ariane 5 Launch System description • 1. Introduction to Space transportation activity • Satellites : missions, configuration, orbits • Market • World-wide competition • Budget overview

4. SPACE MISSIONS OVERVIEW • “Prestige” missions, manned flights • Scientific interplanetary missions ( a few % of automatic flights ) • Scientific mission in earth orbit (astronomy,…) • Operational missions : • telecommunication (most important, the only one being truly commercial ) • meteorology • navigation • Earth observation • micro-gravity research activity

5. Examples of satellites Atlantic Bird : Telecom ERS : Radar earth observation in Sun Synchronous orbit

6. Examples of satellites Integral : Astronomy Sonde Galileo : Solar system exploration

7. Examples of satellites Meteosat : Meteorology ISS and ATV : Manned flight, research

8. CLASSICAL ORBITS Orbits are defined by their altitude (min, max) and angles defining their position in space (inclination, perigee argument, ascending node longitude)

9. CLASSICAL ORBITS Classical orbits are GEO : geostationary earth orbit, reached through GTO, geostationary transfer orbit LEO : Low Earth Orbit < 1 500 km altitude MEO : Medium Earth Orbit (6 000 to 20 000 km altitude) SSO : Sun Synchronous Orbit PEO : Polar Earth Orbit HEO : Highly Elliptical earth Orbit

10. Orbits

11. Orbits

12. Orbits Orbit of Ulysse, solar poles exploration probe

13. Introduction to Space Transportation activity • Main driver for launcher conception • Ariane 5 Launch System description • 1. Introduction to Space transportation activity • Satellites : missions, configuration, orbits • Market • World-wide competition • Budget overview

14. WORLD WIDE LAUNCH MARKET Satellites launches (yearly average, 2001) 45-50 25-30 • Institutional market • Mainly USA & Russia • Europe : 1 to 2 launches per year Commercial market

15. Maximum Nominal COMMERCIAL MARKET Satellites launches (2001)

16. Forecast Completed 35 Digital audio broadcasting satellites 30 90’s: 22 /year All commercial GEO satellites* Fixed service satellites 25 00’s: 19 /year (21 with ICO) 80’s average: 13 /year 20 Mobile communication satellites Number of satellites ICO 15 without 10 70’s average: 4 /year Satellites needed to meet the C & Ku-band transponder demand model 5 0 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 Market study result (e.g. Euroconsult)

17. >5000 Kg 4000-5000 Kg 3000-4000 Kg 2400-3000 Kg <2400 Kg GTO SATELLITES MASS FORECAST (2001)

18. Governmental market : Very important in USA (NASA + DoD : 20 à 25 launches per year) Very weak in Europe: scientific payloads (Envisat, Herschel Planck..), ATV, military activities (com, elint, observation…). Average 1 per year. Commercial market: GEO : important, relatively stable (15 to 20 satellites per year) major part = telecom Stabilization of satellite mass, maximum mass around 6 tonnes LAUNCH MARKET

19. MISSIONS vs ORBITS

20. Introduction to Space Transportation activity • Main driver for launcher conception • Ariane 5 Launch System description • 1. Introduction to Space transportation activity • Satellites : missions, configuration, orbits • Market • World-wide competition • Budget overview

21. LAUNCHER CATEGORIES • Heavy and Super heavy launchers : • Able to lift to all orbits, including GTO and escape, masses of more than 3 tonnes en GTO( heavy ) or more than 10 tonnes en GTO (super-heavy ) • Medium Launchers : • But not adapted to GTO orbit (around 1 tonne) • Able to lift more than 3 tonnes in LEO • Small launchers : • Limited to 1 to 1,5 tonne in LEO • Micro launchers : • limited to a few hundreds of kg in LEO

22. Delta 3 Delta 4 Delta 2 Sea Launch Boeing range of launcher * *Équivalent Kourou EELV new Delta 4 family, mainly to capture government orders marketing of the Zenit, through Sea Launch

23. Atlas 3 Atlas 2 Atlas 5 Proton Lockheed Martin range of launcher * *Équivalent Kourou EELV new Atlas 5 family : proven Atlas 3 technology and Russian RD180 engine marketing of the Proton M through ILS

24. European range of launchers Vega (Arianespace) Rockot (Eurockot) Ariane 5 (Arianespace) Soyouz (Starsem)

25. Space Shuttleused only for US governmental mission, in particular access to International Space Station. Next flight(2nd after Columbia accident in 2004) is scheduled for July 2006. OTHER LAUNCHERS IN THE WORLD

26. Other operational launchers : USA : small launchers Taurus XL, Pegasus XL (air launched) Japan : H2A (heavy launcher), M5 (medium launcher) China : Long March family, medium to heavy launcher India : PSLV, GSLV (medium launchers) Israel : Shavit, (small launcher) Russia / Ukraine : Proton, Soyuz, Cyclone, Zenith 2, Cosmos, Dniepr, Volna, Rockot Launcher in development : Brazil South Korea Russia : Angara Israel : Next Several US private initiatives (Falcon,…) OTHER LAUNCHERS IN THE WORLD

27. SMALL LAUNCHERS (1/2)

31. Introduction to Space Transportation activity • Main driver for launcher conception • Ariane 5 Launch System description • 1. Introduction to Space transportation activity • Satellites : missions, configuration, orbits • Market • World-wide competition • Budget overview

32. USA predominance in the world France, Germany, Italy major contributors in Europe SPACE BUDGETS 1997 25 20 Civilian Military Md € 15 10 5 0 USA Europe Japan Russia SPACE BUDGETS IN THE WORLD

33. SPLIT OF BUDGET PER CIVILIAN APPLICATION

34. Introduction to Space Transportation activity • Main drivers for launcher conception • Ariane 5 Launch System description • 2. Main drivers for launcher conception • Launcher mission and specification • Typical configuration of a launcher

35. Launcher mission consists in giving to the satellite the speed (8 to 10 km/s) and the altitude (200 to 1000 km) needed to reach the intended orbit (injection orbit). This orbit can be the final one, or an intermediate orbit (transfer orbit) Once needed altitude and speed obtained (i.e. once injection orbit reached), the launcher provides adequate orientation and spin Then satellites are separated from the launcher. LAUNCHER MISSION

36. LAUNCH OF A GEOSTATIONNARY SATELLITE launch Orbital manoeuvre (circularisation) in orbit

37. BEGINNING OF SATELLITE LIFE After satellite release, the satellite control centre takes the satellite in charge and controls all operations ( solar panel opening, antennas deployment, checks,…) and manoeuvres (orientations, orbit change,…) needed to begin operational mission.

38. Launch phase induces severe constraints on the satellite, driving its design : Severe mechanical environment (acoustic noise, vibrations, static acceleration, thermal fluxes during count down and during flight) In orbit injection inaccuracy (scattered speed and position leading to a slightly different orbit than the one targeted), which must be corrected by the satellite manoeuvre) Injection attitude inaccuracy (impacting satellite navigation system and thermal control) « Narrow » volume under the fairing, leading to folding / unfolding mechanisms for antennas, solar panels, etc.. CONSTRAINTS COMING FROM LAUNCH PHASE ON THE SATELLITE

39. Launcher specification gathers all satellite customer’s requirements from the launcher : Performance, targeted orbits Satellite orientation at injection Injection accuracy, attitude accuracy Flight environment Mechanical Acoustic Thermal EMC Pollution Available Volume under fairing Services given to the satellite Electrical orders, radio transparent windows under fairing, … Constraints during launch campaign CONSEQUENCES ON LAUNCHER SPECIFICATION

40. Introduction to Space Transportation activity • Main drivers for launcher conception • Ariane 5 Launch System description • 2. Main drivers for launcher conception • Launcher mission and specification • Typical configuration of a launcher

41. A launcher is made of several “stages” Each stage delivers part of speed needed for in orbit injection. Once empty, stage is jettisoned, following one is ignited. Each stage is made around a propulsive system more or less autonomous, comprising : Engines, delivering thrust Tanks, feed system (feeding the engines with propellant), and pressurisation system Connecting structures with other stages Avionic, including software, ensuring following functions : « Guidance/Navigation/Control » (ensure flight control and trajectory optimisation) « Telemetry » (allows post flight check of the correct behaviour of launcher’s subsystems) « Safeguard »(allows protection of goods and people on earth, through ranging of launcher during flight to check trajectory, and potential destruction if it becomes dangerous). Upper Part accommodates the Payloads and protects them from atmosphere Launch Range/Launch Pad Provides facilities for satellite final assembly and tests, before integration atop of the launcher Allows Launcher final assembly and tests, Launcher flight preparation (filling, final checks, take off) Provides Radar ranging and Telemetry acquisition during the whole flight EXPANDABLE LAUNCH SYSTEM TYPICAL CONFIGURATION

42. Why several stages on a launcher ? To inject 1T in LEO (i.e. 7800 m/s + losses =10000m/s) ΔV = go Isp Log (1+k)/k • Conclusions : • With today’s technology: • Storable propulsion : k = 10% • cryo propulsion : k = 10 à 15% • Needed mass ratio for SSTO is not realistic • In addition, high risk in case of drift of mass during project development… Single stage to orbit : today a dream

43. SOLID PROPULSION TECHNOLOGIES Solid propellants : • Isp 260 to 300s • Delivers very high thrust (take off) • High density, => compact stages • Easy / simple ignition • Thrust law (vs time) is frozen once for ever, according to geometry of propellant block • Stop of thrust can not (or hardly) be commanded in real time

44. LIQUID PROPULSION TECHNOLOGIES Liquid propellants : • storable : Isp 260 to 330s • UDMH or MMH + Nitrogen peroxide : most frequent • semi-cryogenic : Isp 300 to 350s • LOX + kerosene, LOX + CH4 • Cryogenic : Isp 425 to 455s • LOX + LH2 very efficient, but complex, and with low propellant density (LH2 70 Kg/m3) • Vacuum thrust quasi constant, or varies slightly with launcher acceleration (variation of pumps inlet pressures). • Engine are hardly throttable • Engine cut-off can be commanded in real time

45. OTHER TECHNOLOGIES • Structures : search for low masses • Light/ strong aluminium alloys • Composites : high pressure filament wound envelopes, NIDA sandwich wrapped shells • Thermal protections • “Hot" : to protect from aerothermodynamics fluxes • “Cold" : for cryogenic propellant tanks • Hydraulic systems • Engine orientation : actuators, hydraulic fluid, electrical pumps or blow down pressure • Pyrotechnic systems • Used for stage separation • Classical pyrotechnic devices, high energy, optopyro transmission • Avionics : use of technology developed for other applications (aeronautics, military) • Hardening to resist to radiations • Software : real time, fault tolerant

46. LAUNCHERS ARCHITECTURE • Number of propulsive stages : • 2 stages for low energy orbit injection (LEO), sometime 3 (Single Stage To Orbit not feasible) • 1 additional stage to reach more energetic orbits • « linear » launchers, or « parallel » launchers (with strap on boosters or stages) • linear : stages assembled one atop of the other, working one after the other • Lateral stages : lowers launcher height (lowering loads on launcher structure), allows simultaneous burning of stage • Air launched launcher (from a plane) : limited to small or micro launchers

47. LAUNCHER ARCHITECTURE • Upper part architecture : • Satellite interface : circular flanges on all launchers, except lateral trunions on Space Shuttle bay • Satellite separation : clamp band or pyro bolts + springs • Avionic lay out : • Gathered in an Avionic bay, or distributed in all stages • Upper stage architecture : • Under fairing (lowers loads and thermal constraints on orbital stage, but more complex fairing) • Or external (simpler, but heavier upper stage)

48. LAUNCH FACILITIES • Constraint applying on Launch Range : • safety during launcher trajectory (=> next to a sea or an unpopulated area) • Wide area needed for launch facility • Proximity to equator (GTO launch) • Access from production facility • Interest of Launch Range allowing to reach orbits of various inclination • Example : KOUROU, ALCANTARA • (need of CCAS and VAB in US for GTO and polar launches) • Interest of maritime platforms questionable (SAN MARCO - SEA LAUNCH) • Launch Ranges are very expansive assets, investment has to be backed by highest launch cadence possible.

49. Trend for future • Cost reduction (market price : low demand, increased offer) • New injection strategies (direct GEO injection, super synchronous orbits) • Transition to fully or partly reusable launchers (in a longer term) : several issues not yet solved : • Technical feasibility • Reusable high performance propulsion • Reusable structure (+ thermal protection), reusable systems (e.g. actuators) • Need of a low number of stages • Operational constraints • Need of a higher reliability (e.g. fault tolerant systems, engine failure) • Overhaul cycle has to be quite shorter than today’s launch operations • Need of a high launch cadence • Otherwise expandable launcher remains cheaper