celestial and spaceflight mechanics laboratory highfidelity
TRANSCRIPT
![Page 1: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/1.jpg)
High-‐Fidelity Small-‐Body Lander Simulations
Stefaan Van wal Simon Tardivel Daniel Scheeres
6th International Conference on Astrodynamics Tools and Techniques Darmstadt, 16 March 2016
University of Colorado Boulder
Celestial and Spaceflight Mechanics Laboratory
![Page 2: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/2.jpg)
Introduction
16 March 2016 High-‐Eidelity small-‐body lander simulations 2
à Increase mission return with lander and surface mobility operations
Small body exploration
Science Resources Planetary defense
à Design requires high-‐5idelity modeling
![Page 3: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/3.jpg)
Contents 1. Framework
2. Gravity
3. Surface
4. Collisions
5. Results and conclusions
16 March 2016 High-‐Eidelity small-‐body lander simulations 3
![Page 4: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/4.jpg)
Framework • SAL software package • Previously: spherical landers
• Currently: extension to arbitrary shapes
• Integration with RK5(4) in C++, event capability
• Propagation relative to rotating target frame
16 March 2016 High-‐Eidelity small-‐body lander simulations 4
![Page 5: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/5.jpg)
Gravity • Constant-‐density polyhedron model, expensive • Method 1: Linearization
§ Acceleration: § Error control with Δrmax
• Method 2: Reduced-‐resolution gravity model § Error control with resolution
16 March 2016 High-‐Eidelity small-‐body lander simulations 5
1,280 facets 200,000 facets
![Page 6: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/6.jpg)
Surface • Surface interactions govern dissipation, high-‐resolution model necessary
• Challenge: collision detection with global surface and rocks
• Method 1: Atlas § Latitude/longitude grid of small local worlds
§ Fast collision detection with single active local world
16 March 2016 High-‐Eidelity small-‐body lander simulations 6
Z-‐atlas
X-‐atlas
![Page 7: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/7.jpg)
Surface • Method 2: Surface rock distribution
§ Affects energy and topographic dissipation § Previously: stochastic model, limitations § Full model is necessary, large # of rocks § Procedural generation on active local world
§ ModiEied icosahedron
16 March 2016 High-‐Eidelity small-‐body lander simulations 7
![Page 8: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/8.jpg)
Surface • Method 3: Bounding spheres
§ DeEined for local worlds, rocks, and lander § Fully encompass target § Trigger Einer collision detection § Fast detection for large # of features
16 March 2016 High-‐Eidelity small-‐body lander simulations 8
dmin%
dmin%
dmin%
![Page 9: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/9.jpg)
Collisions
v nf v s
ω0
v0
ω1
v1
Velocities Impulses
• Impact of arbitrary shapes: § Non-‐eccentric, coupling of normal force and friction
§ Integrated using time-‐like normal impulse p
§ Governed by e and μ § Sliding velocity s, slip vs. stick
§ Contact when vN ~ 0
compression restitution
16 March 2016 High-‐Eidelity small-‐body lander simulations 9
![Page 10: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/10.jpg)
Sample deployment to Itokawa
video placeholder
![Page 11: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/11.jpg)
Results • VeriEication of deployment strategy • Effect of uncertainty in:
§ Release conditions, e.g. altitude § Surface interaction properties, e.g. e and μ § Rock distribution
• Surface mobility operations § Control strategy
• Lander/rover shape optimization • Visualization in OpenGL
16 March 2016 High-‐Eidelity small-‐body lander simulations 11
![Page 12: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/12.jpg)
video placeholder
Lander shape comparison
![Page 13: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/13.jpg)
Impact locations
First impact
Second impact
Release
![Page 14: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/14.jpg)
Conclusions • Elements required for high-‐Eidelity simulations • Methods to reduce numerical burden:
§ Gravity (linearization/resolution) § Surface (atlas/rocks/spheres)
• Collision handling of arbitrary shapes • Enables design and veriEication of lander/rover
• Future work: § Shape optimization § Contact motion § Mission scenarios
16 March 2016 High-‐Eidelity small-‐body lander simulations 14
![Page 15: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/15.jpg)
Sample Mascot-‐2 deployment to Didymoon
video placeholder
![Page 16: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/16.jpg)
Questions?
![Page 17: Celestial and Spaceflight Mechanics Laboratory HighFidelity](https://reader031.vdocuments.site/reader031/viewer/2022012407/616a1d3c11a7b741a34ef59e/html5/thumbnails/17.jpg)
References • S. Tardivel, D.J. Scheeres, P. Michel, S. Van wal, and P. Sanchez, “Contact
motion on surface of asteroid,” Journal of Spacecraft and Rockets , 2014. • S. Van wal, S. Tardivel, and D.J. Scheeres, “Exploring small body surface
with landed pods,” in 12th International Planetary Probe Workshop, Cologne, 2015.
• S. Van wal, “The ballistic deployment of asteroid landers,” M.S. thesis, Delft University of Technology, 2015.
• W.J. Stronge, “Impact mechanics,” Cambridge University Press, 2004. • V. Bhatt and J. Koechling, “Three-‐dimensional frictional rigid-‐body
impact,” Journal of Applied Mechanics , 1995. • S. Tardivel, C. Lange, S. Ulamec, and J. Biele, “The deployment of
Mascot-‐2 to Didymoon,” in 26th AAS/AIAA Space Flight Mechanics Meeting, Napa, CA , 2016.
16 March 2016 High-‐Eidelity small-‐body lander simulations 17