NASA Cost Symposium, 2018 Export Control Notice Export or re-export of information contained herein may be subject to restrictions and requirements of U.S. export laws and regulations and may require advance authorization from the U.S. Government. Lunar Missions: Earth-orbiting or Planetary? Mitch Lasky, Ball Aerospace Joe Hamaker, PhD, Galorath Federal (With Special Thanks to Mary Ellen Harris, the MSFC REDSTAR Librarian) Contents 2 • Motivation • Purpose • Orbit Descriptions • Earth-orbiting, Lunar, Planetary Mission Characteristics • Parametric Analysis • Historical Cost Analysis • Observations Motivation - Exploration 3 Lunar Exploration Missions 4 Power and Propulsion Element 5 NASA Exploration Campaign 6 Motivation 7 • There is a need to credibly estimate cost of lunar orbital and EM L1, L2 missions – Parametric models typically allow selection of Earth- orbiting or planetary mission § Which results in a more credible cost estimate for lunar missions? This study excludes lunar landers Purpose 8 • This presentation will: – Explore characteristics of Earth-orbiting, lunar orbiting, EM L1, L2, and planetary orbits and what drives spacecraft design and cost – Compare results of parametric cost estimates for spacecraft using Earth-orbiting and planetary input selections – Analyze historical spacecraft cost and mass to determine if there is a statistically valid difference in Earth-orbiting, lunar orbiting, and planetary mission cost – Provide near- and long-term suggestions for lunar orbital and EM L1, L2 cost estimates Orbit Description: Earth-orbiting 9 • Distance from Earth – LEO • 160 – 2,000 km – HEO • 16,000 x 133,000 km – MEO • 2,000 – 35,786 km – GEO • 35,786 km Not to scale Orbit Description: Lunar 10 EM L2 ~449,000 km Low Lunar Orbit (LLO) 100 km Mean distance EM L1 384,450 km ~326,400 km ~58,030 km Apogee: 405,504 km Perigee: 363,396 km Not to scale Orbit Description: Planetary 11 • Distance from Earth (closest approach) – Venus § 40 M km – Mars § 56 M km – Moon § 0.36 M km – GEO § 0.036 M km Lunar Orbit 12 • Model as Earth-orbiting or Planetary? Moon Mars 0.36 M km GEO 0.036 M km 56 M km Lunar E-M L1 Not to scale E-M L2 Ø Answer requires more information than distance from Earth Differences Between Earth-orbiting, Lunar Orbital, and Planetary Missions 13 • Propulsion – LEO: optional, rare – Planetary: required to reach destination – Lunar: required to reach destination • Telecom/ADC – Pointing/Ground Station Tracking § LEO: slew s/c or gimbal antenna § Planetary: large distances require fine pointing § Lunar: Distance not as great as Planetary; fast slewing not required – RF Transmit Power § Range dependent o Planetary > Lunar > LEO o Increased mass (and cost) for TWTA and conditioning electronics Differences Between Earth-orbiting, Lunar Orbital, and Planetary Missions 14 • Thermal Control & Battery Degradation ― Eclipse Cycle § LEO: ~14 eclipses/day § Planetary: destination dependent § Lunar: ~14 eclipses/day, some may be long ― Destination Dependence § Distance from sun Distance Solar Flux from Sun Solar Flux (W/m2) Body (AU) (W/m2) [Earth=1] Earth 1.000 1368 1.00 Moon 1.003 1368 1.00 Venus 0.723 2614 1.91 Mars 1.524 589 0.43 Jupiter 5.204 51 0.04 Differences Between Earth-orbiting, Lunar Orbital, and Planetary Missions 15 • Autonomy (FSW) – Time delay proportional to range § Planetary > Lunar > LEO – Number of contacts depends on destination and ground infrastructure – Anomaly may become mission critical failure if response not timely – Autonomy may buy critical time Differences Between Earth-orbiting, Lunar Orbital, and Planetary Missions 16 • Delta-v/Mass Constraint – LEO: Least constrained § Δv ~9 km/s – Planetary: Largest delta-v required -> more fuel -> reduced s/c mass (exotic materials, non-standard manufacturing processes) -> higher cost § Mars Δv ~15-19 km/s – Lunar Δv ~13 km/s • Critical Propulsive Events – LEO: none – Planetary: can be several § Parker Solar Probe has 5 Venus gravity assists – Lunar: § Orbit injection § Periodic orbit maintenance o Asymmetric lunar density resulting in non-uniform gravitational field Differences Between Earth-orbiting, Lunar Orbital, and Planetary Missions 17 • NASA Mission Class – LEO § Typically Class C or Class D – Planetary § Typically Class B or Class C – Lunar § Some Class D – LCROSS, LADEE – Less stringent parts requirements – Full-redundancy may not be required § Some Class B – GRAIL, LRO Destination Comparison 18 Parameter Propulsion Telecom Pointing/Gnd Stn Trkg Telecom Range Battery Degradation Autonomy (FSW) Thermal Control Mass Constraint Delta-V (Inner Planets) Critical Propulsive Events 1=> more benign Destination Comparison 19 Destination Parameter Earth-Orbiting Lunar Planetary Propulsion 1 3 5 Telecom Pointing/Gnd Stn Trkg 4 3 5 Telecom Range 1 3 5 Battery Degradation 3 3 2 Autonomy (FSW) 2 4 5 Thermal Control 3 3 4 Mass Constraint 1 3 4 Delta-V (Inner Planets) 1 3 4 Critical Propulsive Events 1 3 5 Total 17 28 39 1=> more benign • Lunar total not closer to Earth-orbiting or planetary totals • Destination driven characteristics imply lunar orbital mission cost is probably between Earth-orbiting and planetary mission costs Parametric Models: Spacecraft 20 • Modeling methodology – 4 different models – Results estimated for – Earth-orbiting – Planetary – Identical spacecraft MEL used – Results normalized to Earth-orbiting cost Parametric Relative Spacecraft Cost Model Earth-orbiting Planetary SSCM 1 1.2 Commercial 1 1.2 PCEC 1 1.6 QuickCost 1 1.1 Ø Average Planetary to Earth-orbiting cost: 1.3 Lunar Orbiting: Earth-orbiting or Planetary? 21 • Based on qualitative mission requirement differences between Earth-orbiting, lunar, and planetary missions • Lunar orbital and EM L1, L2 mission requirements are a composite of Earth-orbiting and Planetary mission requirements • 30% cost increase over Earth-orbiting mission estimated by a parametric model may be not be justified (Planetary model input selected) • What can we learn from the historical data? Recap of 2017 Cost Results 22 • In our 2017 study, we found that Planetary Missions cost more per unit of mass than Earth Orbital and the difference could be shown to be statistically valid with t-tests and regression analysis ― Well duh ― We only did this test to warm up our t-test jets • We then showed that Lagrange missions were statistically more “birds of a feather” with Earth Orbital Missions than they were with Planetary ― Again, using t-tests and regression Methodology Differences From 2017 Study 23 • Our 2017 study of Lagrange missions used… ― Life cycle cost of the missions (Phase B/C/D/E) § Including Launch Costs ― Dollars per wet kg (because of missing dry mass data) • This 2018 study of Lunar missions used… ― Phase B/C/D (not including Phase E) ― Excluding Launch Costs ― And dollars per dry kg (we filled in missing dry mass numbers) • Why? Because Phase E, Launch Costs and dollars per wet kg added noise to the data • Plus we re-categorized Lagrange missions as Earth Orbital based on the results from our 2017 study Is There A Difference In Cost? 24 • First, we will compare the mean $/Dry kg of the three destinations – Used mean $/Dry kg (i.e., as opposed to just mean $) to correct for the scale difference in the missions • Two sample t-tests were used to investigate if there is a difference in the mean cost of… – Earth Orbital and Planetary missions (just to warm our t-test jets) – Lunar vs Earth Orbital missions – Lunar vs Planetary missions • We will also use regression analysis to examine the predicted cost of the three destinations Cost Database (Showing Only Lunar Missions in the Table) 25 FY2018$Ms Mass (kg) Phase B/C/D Acquisition Cost Launch Organiza Mission Less Launch Cost* We t Dry Orbit Ye ar tion(s) Other Explorer 33 (AKA IMP-D) $144 212 172 Lunar Jul-66 NASA GSFC Explorer 35 (AKA IMP-E) $71 104 84 Lunar Jul-67 NASA LaRC Explorer 49 (AKA RAE-B) $168 334 271 Lunar Jun-73 NASA (Center TBD) Clementine $120 424 227 Lunar Jan-94 NASA, Lunar Prospector $111 295 239 Lunar Jan-98 NASA Ames Lockheed Martin Lunar CRater Observation and Sensing Satellite (LCROSS) $80 892 581 Lunar Jun-09 NASA ARC Gravity Recovery and Interior Laboratory (GRAIL)* $268 307 201 Lunar Sep-11 JPL Lunar Reconaissance Orbiter (LRO) $424 1915 1020 Lunar Sep-13 NASNASAA GSFC Lunar Atmosphere and Dust Environment Explorer (LADEE) $259 384 249 Lunar Sep-13 ARC, * For multi-spacecraft missions the costs reflect only Development through the First Unit • Our database consisted of 71 missions ― 42 Earth Orbital (including Lagrange missions) ― 20 Planetary ― 9 Lunar (shown in table above) including 9 Orbital and 4 missions at L1 and L2 • Note: We left out a few available historical lunar missions which seemed to be outliers ― Surveyor (1966) was a Lunar lander ― Lunar Orbiter (1966) was a very expensive mission (~$1 billion in today’s dollars) ― Artemis P1 was a relocated THEMIS B (2007) spacecraft First Indications… 26 Ratio to Destination $/Dry Kg Earth Orbital Earth Orbital (including Lagrange) $536,272 1.00 Lunar Orbit $685,911 1.28 Planetary $765,327 1.43 • A simple dollars per dry kg calculation indicates that per kg… ― Lunar missions cost 1.28x Earth Orbital ― Planetary missions cost 1.43x Earth Orbital T-Test Comparing Earth Orbital and Planetary Missions 27 Two-sample T for $/dry kg EO=0, PL=1 N Mean StDev SE Mean 0 42 536272 267837 41328 1 20 765327 370926 82942 Difference = mu (0) - mu (1) Estimate for difference: -229055 95% CI for difference: (-418877, -39234) T-Test of difference = 0 (vs not =): T-Value =