Spacecraft Design FRS 148, Princeton University Robert Stengel

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4/25/19

Seminar 10 Chariots for Apollo Spacecraft Design FRS 148, Princeton University Robert Stengel

NASA-SP-4205, Ch 2 to 7 Understanding Space, Ch 11, Sec 13.3, 13.4

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Apollo

Service Module Command Lunar Module Module

Apollo Command and Service Modules (CSM)

§ 3-person crew § Autonomous guidance and control capability

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Apollo Lunar Module (LM)

Project Planning and Contracting

§ Multitude of disparate problems and issues § Mode of reaching the Moon § Definition of the launch vehicles and spacecraft § Deciding where to build and launch them § Deciding who would get the contracts for development and fabrication

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§ First contract to MIT Instrumentation Laboratory for PGNCS R&D § Little else other than the need for guidance, navigation, and control was agreed upon § Persistent competition among manufacturers § Years to come to important conclusions

Apollo Primary Guidance, Navigation, and Control System

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Apollo Command Module Contractor Ratings

§ Real estate for most facets of the program located in the southern US § Access to water transportation § Ice-free water routes § Launch from Cape Canaveral § Politics and financial implications

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Indecision About Alternative Saturn Vehicles

Saturn 1 Saturn 5 Nova (Saturn 8)

11 C-2, C-3, C-4, ...

Contending Modes • Defining mission mode, who would execute it • What was the goal? • First LOR proposal; Tom Dolan, Vought, 1958 • Energy budgets • MALLAR, MORAD, ARP, MALLIR • Safety and reliability of LOR • Number of launches, complexity of systems • Evolution: Mercury, Mercury II (Gemini) • Dynamics of lunar touchdown 12

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Joe Shea • Reaching consensus • Centralizing decision processes at NASA HQ • Lunar crasher • Persistent criticism of LOR from PSAC • Wiesner not a fan of human space flight • Weight-lifting capability of Saturn C-5 • Von Braun’s acquiescence for LOR

Matching Modules and Missions • NASA-NAA relationship, LOR, LEM contractor • Harrison Storms, et al, at NAA • Design and testing facilities • Briefings, agendas, mockups, boilerplates • Test launches, landing systems, cabin • NASA centers, MIT Instrumentation Lab • Quality control and cross-checks • Interface control documents 14

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Jerome Wiesner • Lunar landing vehicle, mysterious surface • PSAC pressures, reliability estimates • JFK’s preoccupation with Cuban missile crisis • Wiesner’s opposition, Webb’s commitment • Responsibility for CSM-LEM rested with MSC • NAA suggested LEM builder be sub-contractor • Grumman vs. McDonnell, other programs in progress, contract negotiations • Integrated Mission Control Center at MSC • Gemini for rendezvous and docking tests 15

Command Module and Program Changes • Selection of CSM-LEM docking configuration • Block I, II CM configurations (before fire) • GE role in ground support • Bellcomm (NASA HQ support contractor) • Apollo Systems Specification manual • Critical Design Review (CDR) • Performance Development Review (PDR) • Lack of cooperation among NASA centers • Telecommunications and Tracking Stations 16

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• Selection of landing sites: • High latitudes • Maria • Inside craters • Near rilles or “wrinkles” • In mountainous areas • Objectives for lunar science: • Lithosphere • Gravitational, magnetic fields • Solar protons, cosmic radiation • Astronomical observatories • Proto-organic material 17

• “Apollo project ... primarily ‘glorious adventure’” • Technical/financial problems in Gemini program • USAF experience in program management • Request for program management plans • Associate administrators • Termination of Saturn I after 10 flights • JFK assassination, criticism of NASA’s priorities18

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• Block I /Block II CM versions • Stabilizing CM during launch abort • Land or water touchdown • Design Reference Mission; responsibilities • Probe-and-drogue docking adapter • Mockup Review Board • Parachute failure, Little Joe II test • From fixed to controlled fins on LJII 19

Lifting Body Re-Entry Vehicles

Northrop HL-10

Martin Marietta X-24A

Northrop M2-F2

JAXA ALFLEX NASA X-38

Martin Marietta X-24B http://www.youtube.com/watch?v=K13G1uxNYks http://www.youtube.com/watch?v=YCZNW4NrLVY 20

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Lunar Landing Flight Simulators

Lunar Landing Research Facility Lunar Landing Research Vehicle

Ground-Based Lunar Landing Simulators, NASA JSC/KFC

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To m Ke lly • Truly unique vehicle; transportation and shelter • Tom Kelly, Grumman, “Father of LEM” • Increased lift capability of Saturn V allowed LEM mass to be increased • Placement and shape of components • Ingress and egress • Ascent stage rocket firing “in the hole” • CM/LEM instruments as similar as possible

• Astronauts played role in CM, LM design • Electroluminescence, Conrad • Standing: crew closer to windows • LM docking and front hatches • Testing criteria for LM ascent engine • Descent engine: “most outstanding technical development of Apollo” • Throttleable thrust • Helium injection, Rocketdyne, rejected • STL: mechanical throttling of descent engine 24

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• Continuing competition between corporations • Bi-propellant RCS thrusters, Marquardt. Thrust spiking problem remediated • RCA: • engineering support • landing and rendezvous radars • sub-sub contract to Ryan • antennas, accuracy, weight • inflight test system • radar control system • In-flight maintenance considered; redundancy chosen instead 25

• Adoption of CM GNC for LM • Everything had to be renegotiated • Reliability, 3-gimbal platform, conflict between Grumman and MIT/IL (“scratchy”) • Mockup reviews • Grumman: Test to failure • Mueller: All-up testing concept

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Searching for Order - 1965 § Flight Article Configuration Inspection (FACI) § Certification of Flight Worthiness (COFW) § Design Certification Review (DCR) § Flight Readiness Review (FRR) § Weight control, configuration control § Unnecessary changes in Block II opposed § LEM testing: a pacing item § Space suit development

Spacecraft Design

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Satellite Buses

Boeing (Hughes) 702 Bus

Boeing Phoenix Bus

Communication Satellites •Mission –Facilitate global communications •Implementation –Transponders with dedicated coverage –Most satellites in geosynchronous orbit Boeing 702 Iridium Satellite –Iridium: 66 satellites in low earth orbit • Satellite phones

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Geostationary Operational Environmental Satellite (GOES-NOP)

Upper Atmosphere Research Satellite (UARS)

•Instruments to measure •Atmospheric chemistry •Atmospheric wind •Solar energy •Infrared spectroscope required cryogenic cooling •Dewar flask •19-month operation

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STEREO, 2006 (Solar TErrestrial RElations Observatory)

• Dual satellites – One ahead of other in Earth orbit – Stereoscopic measurements to study the Sun • Scientific objectives – Mechanisms of coronal mass ejection (CME) – Propagation of CMEs through heliosphere – Mechanisms of energetic particle acceleration – Determination of structure of solar wind

Astronomy Satellites: Hubble

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Astronomy Satellites Chandra X-ray observatory (Shuttle launch, 1999)

James Webb Infrared Telescope to be located at L2 Lagrange point

Chandra, 1999 James Webb Telescope, 2018

Outer-Solar-System Spacecraft: Galileo

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Outer-Solar-System Spacecraft: New Horizons

•Mission duration: 2006-2019+ •Destination: Pluto, Kuiper Belt •Radioisotope thermal power generator •Spin-stabilized in cruise, 3-axis control (hydrazine RCS) for science • Fastest spacecraft to date (Vearth = 16.21 km/s, Atlas 5) • 546,700-kg initial mass • Payload = 478 kg • Jupiter fly-by added 4 km/s to speed 37

Genesis Spacecraft •Genesis Solar Wind Sample Return –Launch: August 2001 –Return: September 2004 (parachute did not open) –http://en.wikipedia.org/wiki/Genesis_spacecraft

Genesis Genesis Retrieval Test

Genesis Reentry 38

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Stardust Spacecraft

•Stardust Wild 2 Comet Tail Stardust Sample Return –Launch: February 1999 –Return: January 2006

Military Satellites •Missions Milstar – Secure observations from space – Early warning – Reconnaissance – Intelligence – Communications SBIRS – Navigation – Weather – Weaponry DSP

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USAF X-37B

• Reusable vehicle • Unmanned “mini- Space Shuttle” • Highly classified • Rocket: AR2-3

• H2O2/JP-8 • Isp = 245 s

CubeSats

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CubeSats § Secondary payloads § Launched directly from ISS § Small launch vehicles

Satellite Systems

• Power and •Structure •Electronics Propulsion –Skin, frames, ribs, –Payload –Solar cells stringers, –Control bulkheads –Kick motor/ –Radio payload assist –Propellant tanks transmitters and module (PAM) –Heat/solar/ receivers –Attitude-control micrometeoroid –Radar shields, insulation –orbit-adjustment transponders –Articulation/ –Antennas –station-keeping deployment –Batteries, fuel mechanisms cells –Gravity-gradient –Pressure tanks tether –De-orbit systems –Re-entry system (e.g., sample return)

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Spacecraft Stiffness* Requirements for Primary Structure

* Natural frequency 45

Landsat-3 Typical Satellite Mass Breakdown

Pisacane, 2005 Satellite without on-orbit propulsion Kick motor/ PAM can add significant mass 46 Total mass: from a few kg to > 30,000 kg

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Expanded Views of Spacecraft Structures

Primary and Secondary Structure

• Instrument Module provides – Support for 10 scientific instruments – Maintains instrument alignment boresights – Interfaces to launch vehicle (SSV) • Secondary Structure supports – 6 equipment benches – 1 optical bench – Instrument mounting links – Solar array truss – Several instruments have kinematic mounts

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Upper-Atmosphere Research Satellite (UARS) Primary and Secondary Structure

• Primary Structure provides – Support for scientific instruments – Maintains instrument alignment boresights – Interfaces to launch vehicle • Secondary Structure supports – Equipment benches – Optical bench – Instrument mounting links – Solar array truss – Instruments with kinematic mounts 49

Textbook Example (Fundamentals of Space Systems, 2005)

• Atlas IIAS launch vehicle • Spacecraft structure meets primary stiffness requirements • Axial stiffness requirements for Units A and B? – Support deck natural frequency = 50 Hz

Octave Rule: Component natural frequency ≥ 2 x natural frequency of supporting structure

• Unit A: 2 x 15 Hz = 30 Hz, supported by primary structure • Unit B: 2 x 50 Hz = 100 Hz, supported by secondary structure 50

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Factors and Margins of Safety • Factor of Safety – Typical values: 1.25 to 1.4 Load (stress) that causes yield or failure Expected service load • Margin of Safety – the amount of margin that exists above the material allowables for the applied loading condition (with the factor of safety included), Skullney, Ch. 8, Pisacane, 2005 Allowable load (yield stress) −1 Expected limit load (stress) × Design factor of safety

Finite-Element Structural Model § Grid of elements, each with § Mass, damping, and elastic properties § 6 degrees of freedom at each node § Static and dynamic analysis

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Types of Finite Element

Fortescue, 2011

Structural Modeling Using PTC CREO

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Spacecraft Power

Typical Electrical Power Requirements

• Generate electrical power for s/c systems • Store power for “fill-in” when shadowed from Sun • Distribute power to loads • Condition power (e.g., voltage regulation) • Protect power bus from faults • Provide clean, reliable, uninterrupted power

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Power Management and Distribution

Power System Sizing • Requirements – Support the spacecraft through entire mission – Recharge batteries after longest eclipse – Accommodate electric propulsion loads – Accommodate failures to assure reliability – Account for margins and contingencies • Factors affecting size – Satellite orbit – Time of year/seasonal variation – Life degradation/environmental effects – Total eclipse load

– Number of discharges 58

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Power System Tradeoffs

Solar Cells

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Solar Cells

• Silver, palladium, titanium, silicon” sandwich” • Photons hit panel • Electrons are excited, generating heat or traveling through material, e.g., boron or phosphorus, generating a current 61

Solar Cell Types and Characteristics • Silicon (Efficiency < 15%) • Gallium Arsenide (Efficiency: 22-30%)

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Functional Blocks of Electrical Power System

• Energy generation • Energy storage • Power management and distribution

Batteries

• Nickel Cadmium (NiCd) – Heavier, older tech – Lower volume • Nickel Hydrogen (NiH2) – Present tech – Pressurized vessels • Lithium Ion (Li Ion) – State of the art – ½ the mass, 1/3 the volume of NiH2 – Extra care required 64

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Proton Exchange Membrane Fuel Cell

Gemini Fuel Cell

Radioactive Isotope Thermoelectric Generator (Cassini Spacecraft)

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Thermal Control

Typical Temperature Requirements

• Maximum & minimum operational/non- operational temperatures • Maximum diurnal swing • Maximum gradients • Survival/safe state temperature • Allowable rate of change • Control requirements of sub-systems

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J. C. Keesee 69

Thermal Design Environments

• Pre-launch (shipping, on pad) • Launch and transfer orbit • Mission characteristics – On orbit – On surface • Sun exposure • Shadow

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Thermal Design Task

Heat Sources

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Thermal Design Constraints

• Equipment utilization philosophy • Design margin philosophy • Failure mode philosophy • Power system margin • Mass budget • Temperature specifications • Sun/shadow duty cycle • Equipment redundancy

Thermal Analysis • Steady state (thermal equilibrium) • Transient • Thermal network models – Nodes • Elements that can be characterized by a single temperature • Energy storage devices – Conductors • Energy transport – Energy sinks • Closed-form idealizations • Finite element/difference software 74

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Types of Thermal Control • Passive – Coatings and paints – Thermal isolation – Heat sinks – Phase Change Materials • Active – Heaters – Heat pipes – Thermoelectric devices – Thermal louvers

Reflectors, Insulation, and Louvers

Mars Reconnaissance Orbiter

Multi-Layer Insulation

Messenger Thermal Louvers

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Heat Pumps

Capillary Pumped Loop Looped Heat Pipe

Next Time: Project Management and System Design Spacecraft Guidance

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Supplemental Material

STEREO Spacecraft Primary Structure Configuration Solar TErrestrial RElations Observatory

• Spacecraft structure – Beams – Flat and cylindrical panels – Cylinders and boxes • Primary structure: rigid skeleton of the spacecraft • Secondary structure: bridge to primary structure for components

Pisacane, 2005 80

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Spacecraft Mounting for Launch

• Spacecraft protected from atmospheric heating and loads • Fairing jettisoned when atmospheric effects are negligible • Spacecraft attached to rocket by adapter, transfers loads • Spacecraft (usually) separated from rocket after thrusting • Clamps and springs for attachment and separation

Fairing Constraints for Various Launch Vehicles

• Static envelope • Dynamic envelope accounts for launch vibrations, with sufficient margin for error • Various appendages stowed for launch • Large variation in spacecraft inertial properties when appendages are deployed

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Typical Acoustic and Shock Environment (Delta II) Sound Pressure (dB) Peak Acceleration (g)

Decibel (dB) ⎛ Measured Power⎞ ⎛ Measured Amplitude⎞ 10log10⎜ ⎟ or 20log10⎜ ⎟ ⎝ Reference Power ⎠ ⎝ Reference Amplitude⎠ 83

Transient Loads at Thrusting Cutoff (Spacecraft Systems Engineering, 2003)

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Fundamental Vibrational Frequencies of Circular Plates f = natural frequency of first mode, Hz

Fracture and Fatigue Failure from Repeated/Oscillatory Loading § Cyclic loading produces cracks § Fatigue life: # of loading cycles before failure occurs

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Maximum Deflection and Bending Moment of Beams (see Fundamentals of Space Systems for additional cases)

Fixed-Free Beam Fixed-Fixed Beam Pinned-Pinned Beam

Ymax = maximum deflection Mmax = maximum bending moment 87

Maximum Deflection and Bending Moment of Plates (see Fundamentals of Space Systems for additional cases)

Circular Plate

m =1/ν

Rectangular Plate

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Critical Stress for Plate and Cylinder Buckling

Typical Cross-Sectional Shear Stress Distribution for a Uniform Beam

• Shear stress due to bending moment is highest at the neutral axis

• Maximum values for various cross sectons (see Fundamentals of Space Systems)

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Fairing Inner Surface Maximum Temperatures