Josef Koller, ISR-1. NADIR Meeting Website

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1 LA-UR Approved for public release; distribution is unlimited. Title: IMPACT Project: Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking - A New Orbital Prediction Model to Avoid Collisions in Space Author(s): Josef Koller, ISR-1 Intended for: NADIR Meeting Website Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes. Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Los Alamos National Laboratory strongly supports academic freedom and a researcher s right to publish; as an institution, however, the Laboratory does not endorse the viewpoint of a publication or guarantee its technical correctness. Form 836 (7/06)

2 IMPACT: Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking Josef Koller, ISR- 1, LANL Abstract: The United States relies heavily on its space infrastructure for a vast number of applications, including communication, navigation, banking, national security, and research. However, NASA predicts that between now and 2030 orbital collisions will become increasingly frequent and could reach a runaway environment. This devastating scenario, also known as the Kessler Syndrome, will eventually destroy our assets in near Earth space and result in a debris cloud that could make space itself inaccessible. Preventing the Kessler Syndrome requires, in addition to an object removal technique, a groundbreaking new orbital dynamics framework that combines a comprehensive physics- based model of atmospheric drag with an accurate uncertainty quantification of orbital predictions. To achieve this goal, we will develop and calibrate a new physics based atmospheric dynamics model that is driven by space weather and suitable for orbital drag calculations. Our physics model will be based on a 3- D coupled ionosphere- thermosphere model solving the full Navier- Stokes equations for density, velocity and temperature for a number of neutral and charged components. This will allow us to study in detail the complex energy absorption of solar UV photons, deposition and Joule heating by precipitating particles, global redistribution and cooling. In addition to a new physics- based atmospheric density model, we will advance the field by providing accurate uncertainty quantifications of orbital predictions obtained using a full probability distribution in place of a limiting Gaussian assumption. This project offers an exciting opportunity for scientific studies of the upper atmosphere by using satellites as test particles and pinpointing the physical processes responsible for the spatial and temporal variation of atmospheric drag. Results from this work will be highly relevant for the space situational awareness portfolio at LANL, which is a key topic in the Grand Challenge for Sensing and Measurement Science for Global Security.

3 IMPACT Project Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking A New Orbital Prediction Model to Avoid Collisions in Space PI: Josef Koller, ISR-1 jkoller@lanl.gov Operated by the Los Alamos National Security, LLC for the DOE/NNSA

4 IMPACT is a new project at Los Alamos IMPACT stands for: Integrated Modeling of Perturbations in Atmospheres for Conjunction Tracking Laboratory Directed Research and Development (LDRD) funded: FY12,13,14; total $5.3M LANL highlights: Approx. 12,000 employees (~3500 scientists) Known for nuclear weapons but also many other science areas (astrophysics, space, plasma, geo, bio physics, chemistry, material science, computing, ) Project housed in Intelligence and Space Research Division as part of the Global Security Directorate

5 IMPACT Team together has wide background Participants include scientist from ISR, T, CCS and AFRL Kirtland, Univ. Michigan, GA Tech (soon UT Austin) Josef Koller (PI) space science, data assimilation, hydrodynamic modeling David Thompson, Alexei Klimenko, David Palmer observations Balu Nadiga Global circulation models, data assimilation David Higdon, Earl Lawrence, Humberto Godinez statistics, applied mathematics, data assimilation Michael Henderson space physics, computing Brendt Wohlberg data assimilation, machine learning Cheryl Huang, Chin Lin, Kyle DeMars, Eric Sutton, Fred Leve, Moriba Jah, Thomas Lovell, Sam Cable, Yi-Jiun Caton thermospheric modeling, astrodynamics (AFRL) Aaron Ridley GITM Thermospheric modeling (Univ. of Michigan) Ryan Russell astrodynamics (soon UT Austin)

6 Project was motivated by Iridium-Cosmos Feb 10 th, 2009: Iridium 33 and Cosmos 2251 unexpectedly collided at 12 km/s in 800 km altitude. SOCRATES system predicted only close conjunction (~584m) ranking of close conjunctions never in top ten (#152 overall) Iridium-Cosmos collision generated over 2100 debris pieces many smaller ones still big enough to damage other spacecraft generated two rings of debris in 770 km altitude Donald Kessler (NASA) predicted in 1978 a runaway environment of collisions in space to start between (Kessler Syndrome) cascading collisions could make space inaccessible. enormous threat to our space assets and global security

7 Why was this collision not predicted and avoided? Several factors contributed to the collision: inadequate specifications of orbit measurements are expensive inadequate atmospheric drag model accurate orbital propagator is the key Current orbital propagator: Space weather effects not sufficiently described Satellite drag modeled only with one average ballistic coefficient Uncertainty model is only Gaussian Courtesy: AGI

8 Scientific Goals of the IMPACT project: What are the missing physical processes that drive the atmospheric density causing orbital drag variations? How can we accurately quantify the uncertainty of atmospheric model, drag model, orbital propagator? space weather sciences POD data and imaging uncertainty quantification IMPACT drag and dynamics model Programmatic goal: end-to-end model with a physics-based density model for satellite drag + non-gaussian UQ for collisional probabilities

9 An inaccurate density model will cause significant errors on orbital parameters Misrepresenting the real air density by a factor of four can lead to errors in orbital parameters: r ~ 600m in just ½ day. -- real density initial r = 550 km -- density model 600m

10 Physics-based neutral density modeling Current models are empirical: Jacchia-Bowman Series, MSIS Series, etc are based on spherical harmonics expansion; include Ap, F10.7 flux as parameter Physics based models: TIEGCM: hydrostatic model (developed at NCAR) GITM: fully hydrodynamic model (developed at Michigan) GITM Has cooling and heating processes included coupled with EUV and precipitation data stong thermospheric winds Approach: data assimilation with a combination of parameter fine-tuning Courtesy: Ridley UNCLASSIFIED

11 Non-Gaussian Uncertainty Quantification is necessary An initial Gaussian error distribution evolves within one orbit into a non-gaussian distribution. A Splitting Gaussian Mixture Model can automatically add more Gaussians as needed. our simulation Source: DeMars, Jah

12 Collision probabilities will be more accurate with proper non-gaussian PDF uncertainties Currently, position uncertainties are described with simple error ellipsoids. The collision probability depends on the integral over the probability distribution functions. Source: AGI Adapted from: DeMars, Jah

13 Tumbleweeds in Space High Area to Mass Ratio Object (HAMR) Mylar films acting like solar sails in GEO Orbit poorly predictable Photon pressure Solar-lunar gravitational perturbation Threat to geosynchronous spacecraft New modeling components required: Solar wind pressure Charging effects Magnetic field effects

14 Summary IMPACT is a new LDRD-DR project to address thermospheric density changes driven by space weather with a physics based model develop proper non-gaussian uncertainty quantifications for conjunction probablities Interdisciplinary team from three divisions: ISR, CCS, T external collaborators: AFRL (Kirtland), Univ. Michigan, UT Austin Plan to hire 2-3 postdocs Collaborations are very welcome Website: (coming soon)