Aerospace Engineering Commons^™

Infrared Spectral Responses Of The Ocean Color Instrument (Oci) Pre-Assembly And Integration, Jacob K. Hedelius, Kenneth J. Squire, James Q. Peterson, Branimir Blagojević, Ulrik B. Gliese, Eric T. Gorman, David K. Moser, Zakk Rhodes, Pedro Sevilla, Gerhard Meister

Space Dynamics Laboratory Publications

Spectral characterizations were made of the Ocean Color Instrument (OCI) short-wave infrared (SWIR) Detection Subassembly (SDS) responses (940–2260 nm) prior to their integration. Using modulated output light from a Fourier transform spectrometer, the in-band relative spectral responses of the nine different configurations of SDSs were found along with out-of-band (OOB) sensitivity. From these spectral responses, the center wavelengths (λ₀), full widths at half of the maximum, full widths at 1% of the maximum, and OOB rejection ratios were determined. All spectral parameters are within requirements. There are 2–8 repeats of each configuration, and the 1 σ spread among …

A Network Flow Approach For Constellation Planning, Skylar A. Cox, Greg N. Droge, John H. Humble, Konnor D. Andrews

Space Dynamics Laboratory Publications

A graph-based network flow approach to constellation planning is presented that respects spacecraft resources and mission constraints to arrive at a preliminary operational schedule. The method discretizes task fulfillment opportunity windows into graph nodes and then adds edges based on feasibility of transition between these opportunities, either by slew maneuvers or extended-time task fulfillment during downlink operations. Intelligent graph pruning is applied to improve computation performance and provide a versatile planning capability with a minimal impact on the resulting solution. A network flow formulation allows for a simultaneous search for spacecraft plans using a Mixed Integer Linear Program (MILP). The …

Mission Operations, Utah State University Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Overview

• In review – CONOPS

• Mission Planning

• Anomaly Resolution

• Miscellaneous, but important considerations

• Looking forward

Ground Support Equipment (Gse) Eat, Utah State University Space Dynamics Laboratory

Space Dynamics Laboratory Publications

About this Presentation

• This presentation was developed as a “taste” of the area of GSE
• There are lots of resources that can be found about GSE and how it should be used
• While I have tried to cover a lot of ground in this presentation, the GSE required for your mission will vary depending on your application
• My intent is to start the thinking process of how to design, develop, and execute GSE elements of your program so that you have a successful mission

Spacecraft Formation Flying Control Switching Surface Based On Relative Orbital Elements, Tyson K. Smith, John Akagi, Greg Droge

Space Dynamics Laboratory Publications

The development of a switching surface constraint based on the D’Amico relative orbital elements (ROE) is presented in this paper. Relative orbital elements give a more intuitive understanding of how the relative motion of a cluster of satellites changes with time and allows the control algorithm to take advantage of the natural dynamic motion. This work models each vehicle using a model predictive control (MPC) approach, based on the Hill-Clohessey-Whiltshire (HCW) equations, to plan maneuvers which are simulated using a high-fidelity motion model. An ROE based convex polytope switching surface is added to the MPC formulation to force the states …

Ground Station Eat, Utah State University Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Ground Components

Two primary subsystems

•Ground Station(s)

•  May be your own or commercial
• Includes radio(s), antenna(s), rotor, etc.
• Heavily intertwined with satellite communications system
• Influences link budget

•Ground data system

• Your command, control, and telemetry interface
• Operator facing tools
• Front end processor
• Includes computer(s), networking equipment, displays, software tools, etc.
• Directly links to your ground station via network

•Additional ground subsystems could include:

• Payload ground (i.e. optical ground terminal)
• Space comm networks (i.e. Iridium)

A Monolithic Solid-State Interferometer For Real-Time Multi-Environment Measurements, Aaron J. Pung

Space Dynamics Laboratory Publications

The high degree of precision offered by optical interferometry makes it an ideal tool in many applications, including vibration detection, wind tunnel aerodynamics, surface topology measurements, and environmental sensing. In the latter case, real-time measurement of real-world environments is crucial to ensuring the health and safety of individuals operating within domestic and industrial domains. Currently, these measurements are made possible with portable fiber-based interferometer systems – systems that are also limited by high cost, fragility, coupling loss, and low power. This work presents a lightweight free-space interferometer that is versatile, modular, and compact. The interferometer is monolithic, geometrically simple, easy …

A Two-Layer Constellation Scheduling Approach For Imaging And Communication, Skylar Cox, Justin Whitaker, John Humble, Greg Droge

Space Dynamics Laboratory Publications

Spacecraft constellations continue to grow in numbers, capability, and sophistication, requiring in creased levels of automation to properly cooperate in achieving their objectives. This paper develops a constellation scheduling capability for collecting images of points of interest (POI) and communicating the imagery data through the constellation to established ground station terminals. Various levels of coordination are considered. First, satellites coordinate to avoid duplicate efforts for imaging POIs; second, ground stations only service a single satellite at a time for downlinking; and third, satellites may crosslink data within the constellation to enable a more timely delivery of high-valued information as well …

Frequency-Dependent Linearity Characterization And Uncertainty Analysis Of The Pace Oci Short-Wave Infrared Detection Assembly, Kenneth Squire, Jacob Hedelius, James Peterson, Eric Gorman, Gerhard Meister

Space Dynamics Laboratory Publications

The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Ocean Color Instrument (OCI) will be used to collect data on the health of the planet’s oceans and atmosphere. Essential to OCI is its Short-Wave Infrared (SWIR) Detection Assembly (SDA), which measures light at discrete bands of interest. The linearity knowledge of the SDA detectors is crucial for collection of accurate and meaningful scientific data. This document presents the methodology employed in measuring the linearity response of the SDA to optical inputs at various modulation frequencies as well as the accompanying linearity uncertainty analysis.

Europa Environmental Testing Of Thermal Hardware For The Mapping Imaging Spectrometer For Europa (Mise) Instrument, Ian M. Mckinley, Jose I. Rodriguez, Mason Mok, Kristen S. Maynard, Curtis Bingham, Andrew Ostler, Patrick Strong

Space Dynamics Laboratory Publications

The Europa Clipper spacecraft, scheduled for launch in June 2022, hosts a suite of instruments including the Mapping Imaging Spectrometer for Europa (MISE). MISE is a high-optical through-put push-broom infrared imaging spectrometer that can collect measurements within Europa’s challenging radiation environment. It is externally mounted to the spacecraft and as a result is exposed to high radiation levels and cold temperatures. The instrument consists of a scan mirror assembly, an optical bench including a Dyson spectrometer and a telescope, and a structure that supports a cryocooler and a radiator. The cryocooler is used to actively cool the focal plane array …

Transport-Based Pattern Recognition Versus Deep Neural Networks In Underwater Oam Communications, Patrick L. Neary, Jonathan M. Nichols, Abbie T. Watnik, K. Peter Judd, Gustavo K. Rohde, James R. Lindle, Nicholas S. Flann

Space Dynamics Laboratory Publications

Comparisons between machine learning and optimal transport-based approaches in classifying images are made in underwater orbital angular momentum (OAM) communications. A model is derived that justifies optimal transport for use in attenuated water environments. OAM pattern demultiplexing is performed using optimal transport and deep neural networks and compared to each other. Additionally, some of the complications introduced by signal attenuation are highlighted. The Radon cumulative distribution transform (R-CDT) is applied to OAM patterns to transform them to a linear subspace. The original OAM images and the R-CDT transformed patterns are used in several classification algorithms, and results are compared. The …

Autonomous Optimal Trajectory Planning For Orbital Rendezvous, Satellite Inspection, And Final Approach Based On Convex Optimization, Nicholas Ortolano, David K. Geller, Aaron Avery

Space Dynamics Laboratory Publications

Convex optimization techniques have deterministic convergence properties, are self-starting, i.e., they do not require an initial guess, and have been tested in real-time environments. These optimization techniques are applied to the trajectory planning problem for orbital rendezvous and proximity operations. Spacecraft rendezvous, inspection, and final approach trajectories are considered. Optional trajectory constraints are considered, including approach corridors, keep-out zones, and maximum thrust acceleration levels. Two linear dynamics models are investigated: Clohessy-Wiltshire dynamics to describe the relative motion in a local-horizontal local-vertical frame, and a new relative orbital motion dynamics model to describe the motion relative to a spinning or uncontrolled …

Intelligent Management Of Constrained Links For Distributed Autonomy, Troy R. Johnson, Nathan A. Jensen

Space Dynamics Laboratory Publications

This paper addresses one of the main underlying obstacles overlooked when adding autonomy to a cooperative cluster of nodes working together to complete global objectives. Whether these nodes are ground, sea, air, or space vehicles, a constrained link is used to distribute information between the vehicles. The limited bandwidth of the constrained link must be shared between all nodes and becomes a pinch point for distributed autonomy. Intelligently managing the shared information and controlling how it is replicated across all nodes is vital. Lack of communication results in poor team performance. Intermittent connectivity and delayed intelligence sharing leads to the …

Cnn Classification Architecture Study For Turbulent Free-Space And Attenuated Underwater Optical Oam Communications, Patrick L. Neary, Abbie T. Watnik, Kyle Peter Judd, James R. Lindle, Nicholas S. Flann

Space Dynamics Laboratory Publications

Turbulence and attenuation are signal degrading factors that can severely hinder free-space and underwater OAM optical pattern demultiplexing. A variety of state-of-the-art convolutional neural network architectures are explored to identify which, if any, provide optimal performance under these non-ideal environmental conditions. Hyperparameter searches are performed on the architectures to ensure that near-ideal settings are used for training. Architectures are compared in various scenarios and the best performing, with their settings, are provided. We show that from the current state-of-the-art architectures, DenseNet outperforms all others when memory is not a constraint. When memory footprint is a factor, ShuffleNet is shown to …

High Performance Thermal Straps For A Full Range Of Application Temperatures, M. Ralphs, M. Sinfield, M. Felt

Space Dynamics Laboratory Publications

Thermal straps are an essential component when using vibration sensitive instruments and cryocoolers in close proximity. Thermal straps conduct heat from the instrument to the cryocooler while limiting the amount of mechanical vibration the cryocooler transfers back to the instrument. Thermal straps are made from flexible, thermally conductive materials. Traditionally, they are made of metal – aluminum or copper, mostly – that has been formed into thin foils, wires, or braids to provide greater flexibility while still providing good thermal conductivity. These metallic straps, if made from pure metals, provide superior thermal performance at cryogenic temperatures ( < 60 K ) where their thermal conductivities peak to extraordinary levels. Pyrolytic graphite sheet (PG S) thermal straps have a thermal conductance that peaks at higher temperatures – approximately 160 K – and provide much higher mass-specific thermal conductance at temperatures above 60 K than metallic straps. This paper discusses the pros and cons of aluminum, copper, and PG S thermal straps along with different techniques to test their thermal and mechanical performance.

Quantum Frontiers: To Boldly Go, Michael Dixon, Cali Christensen, Rachael Leisek

Space Dynamics Laboratory Publications

We have lift off!

Cali Christensen started her summer at Quantum Frontiers (QF) at an intern lunch. Seated around her were 20 other interns from universities all over the country who had been selected from a pool of over 900 applicants to participate in high-tech, space-related research endeavors pushing the boundaries of various fields such as engineering, mathematics, computer science, machine learning, and physics. Cali quickly realized after the first presentation that she may be one of the only non-engineer or scientists in the room. Her internship was different from any others that QF had yet sponsored. Instead of making …

Linear Covariance Navigation Analysis Of Range And Image Measurement Processing For Autonomous Lunar Lander Missions, Randall Christensen, David Geller, Michael Hansen

Space Dynamics Laboratory Publications

Growing interest in autonomous landing on the lunar surface has motivated in-depth studies of the navigation architectures to support such missions. The research presented in this paper extends linear covariance models of terrain-relative navigation architectures to incorporate both image-based measurements to known landmarks and laser range measurements to the lunar surface. The benefit of the range measurements is shown to be significant in reducing relative position and velocity errors in the altitude channel, as compared to an image-only navigation architecture. The range measurements are also shown to reduce the sensitivity of final relative navigation errors to the turn-on time of …

New Constraint-Driven Mission Construct For Small Satellites And Constrained Missions, Lee Jasper, Barbara Braun, Lauren Hunt

Space Dynamics Laboratory Publications

Small satellites, though increasingly prevalent in the industry today, tend to not follow traditional development paths, technically or programmatically. In contrast to traditional requirements-driven missions, where meeting requirements is the primary metric of success, small satellite missions tend to be constraints-driven, where mission scope is tradable to maintain cost and schedule constraints.

Clean, Robust Alkali Sources By Intercalation Within Highly Oriented Pyrolytic Graphite, Rudolph N. Kohn Jr., Matthew S. Bigelow, Mary Spanjers, Benjamin K. Stuhl, Brian L. Kasch, Spencer E. Olson, Eric A. Imhof, David A. Hostutler, Matthew B. Squires

Space Dynamics Laboratory Publications

We report the fabrication, characterization, and use of rubidium vapor dispensers based on highly oriented pyrolytic graphite (HOPG) intercalated with metallic rubidium. Compared to commercial chromate salt dispensers, these intercalated HOPG (IHOPG) dispensers hold an order of magnitude more rubidium in a similar volume, require less than one-fourth the heating power, and emit less than one-half as many impurities. Appropriate processing permits exposure of the IHOPG to atmosphere for over ninety minutes without any adverse effects. Intercalation of cesium, potassium, and lithium into HOPG has also been demonstrated in the literature, which suggests that IHOPG dispensers may also be made …

Ground And In-Flight Calibration Of The Osiris-Rex Camera Suite, D. R. Golish, C. Drouet D'Aubigny, B. Rizk, D. N. Dellagiustina, P. H. Smith, K. Becker, N. Shultz, T. Stone, M. K. Barker, E. Mazarico, E. Tatsumi, R. W. Gaskell, L. Harrison, C. Merrill, C. Fellows, B. Williams, S. O'Dougherty, Michael Whitely, Jed Hancock, B. E. Clark, C. W. Hergenrother, D. S. Lauretta

Space Dynamics Laboratory Publications

The OSIRIS-REx Camera Suite (OCAMS) onboard the OSIRIS-REx spacecraft is used to study the shape and surface of the mission’s target, asteroid (101955) Bennu, in support of the selection of a sampling site. We present calibration methods and results for the three OCAMS cameras—MapCam, PolyCam, and SamCam—using data from pre-flight and in-flight calibration campaigns. Pre-flight calibrations established a baseline for a variety of camera properties, including bias and dark behavior, flat fields, stray light, and radiometric calibration. In-flight activities updated these calibrations where possible, allowing us to confidently measure Bennu’s surface. Accurate calibration is critical not only for establishing a …

Dynamics Within A Tunable Harmonic/Quartic Waveguide, Rudolph N. Kohn Jr., James A. Stickney

Space Dynamics Laboratory Publications

We present an analytical solution to the dynamics of a noninteracting cloud of thermal atoms in a cigar-shaped harmonic trap with a quartic perturbation along the axial direction. We calculate the first and second moments of position, which are sufficient to characterize the trap. The dynamics of the thermal cloud differ notably from those of a single particle, with an offset to the oscillation frequency that persists even as the oscillation amplitude approaches zero. We also present some numerical results that describe the effects of time-of-flight on the behavior of the cloud in order to better understand the results of …

Constellation Planning Methods For Sequential Spacecraft Rendezvous Using Multi-Agent Scheduling, Skylar A. Cox, Nathan B. Stastny, Greg Droge, David K. Geller

Space Dynamics Laboratory Publications

This paper addresses the RPO constellation assignment problem by developing a responsive utility function for tasking a constellation of LEO satellites to several spacecraft servicing tasks. The paper develops the utility function that considers both value of servicing RSO spacecraft in conjunction with the associated ΔV cost. A highly-capable and operationally-relevant task allocation method, called the consensus-based bundle algorithm (CBBA), is leveraged for distributed processing and task allocation. This paper demonstrates that this methodology provides a robust technique for RPO constellation management.

Four-Wavelength Lidar For In-Situ Speciation Of Aerosols, Michael Wojcik, Alan Bird, Jason Wooden, Jim Peterson, Morgan Davidson, Monte Frandsen

Space Dynamics Laboratory Publications

The system and mechanical design of a four-wavelength lidar system is described. The system is designed to be maximally adaptive to deployment scenario in terms of both size/weight/power and detection application. The wavelengths included in the system are 266 nm, 355 nm, 1064 nm, and 1574 nm – all generated from Nd:YAG based pump laser sources. The system is designed to have a useful range from 400 meters to 5,000 meters, depending on the wavelength and atmospheric conditions.

Clutter Suppression For Bistatic Gmti Using Along-Track Interferometry, Ross Deming, Chad Knight

Space Dynamics Laboratory Publications

An adaptation of along-track interferometry (ATI) clutter suppression signal processing is described for bistatic geometries in which the radar transmitter and receivers fly independently on separate platforms. Despite the more complicated geometry, this approach retains the simplicity and computational efficiency of standard monostatic ATI. Bistatic and multi-static (bistatic plus monostatic) geometries can yield significant performance advantages compared with monostatic in terms of detecting and geo-locating moving ground targets. We present results from simulated multi-static data that validate the ATI technique and illustrate the advantages. If time allows, we will also present results from an experimental flight test in the final …

Affordable Small System Calibration & Tvac Testing, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Ensure that your sensor will perform correctly during operation by validating image quality, radiometric performance, and operation temperature performance!

The Space Dynamics Laboratory (SDL) has been calibrating electro-optical sensors for over 50 years. During this time, SDL has designed and developed a collection of specialized equipment that is available for calibrating smaller optical systems, which can be very affordable.

Optimal Maneuvers For Safe Rpo Using Relative Orbital Elements And Sequential Convex Programming, Nicholas G. Ortolano, David K. Geller, Aaron Avery

Space Dynamics Laboratory Publications

Passive safety of flight constraints for orbital rendezvous and proximity operations trajectory design are imposed as a means for ensuring zero probability of collision in the event of a passive failure on the chaser satellite. For a chaser satellite near a target satellite in a near circular reference orbit, relative orbital elements are used to develop safety of flight constraints. Using relative orbital elements, the problem is formulated as a minimum ∆v convex optimization problem in which the optimal transfer trajectories are guaranteed to not pass within a prescribed distance of the target satellite in the event of a …

Thermal Straps: High-Performance Thermal Management, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Thermal straps efficiently transfer heat from a heat source to a temperature sink while minimizing the transfer of mechanical loads. SDL has been pioneering solderless flexible thermal straps (a.k.a. thermal links) since 1994.

Monolith: Spacecraft, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

SDL’s Pearl spacecraft architecture delivers the performance, reliability, and mission flexibility needed for demanding small satellite missions. The Pearl architecture draws from common sets of components to build 3U, 6U, 12U, and custom sizes with variations in mission capability, parts quality, and radiation tolerance. This flexibility enables our professional staff to develop systems specific to each mission while drawing on a common design to maintain reliability and costs.

Snpp Cris Noise Characterization And Relative Response After 5 Years In Space, Kori Moore, Mark Esplin, Deron Scott

Space Dynamics Laboratory Publications

CrIS Background

Satellite-based, infrared, Fourier transform spectrometer

• Provides Earth surface, atmospheric, and weather observations
• Global coverage twice daily

Launched and operational CrIS instruments

• Suomi National Polar-orbiting Partnership (SNPP) spacecraft, launched Oct. 2011, operational since Apr. 2012
• SNPP follow-on system (J1) launched Nov. 2017, expected operational spring 2018

A Performance Analysis Of On-Board Numerical Propagators, Simon Shuster, David Geller, Tyson Smith

Space Dynamics Laboratory Publications

On-board targeting, guidance, and navigation relies on orbit propagation algorithms that must strike a balance between accuracy and computational efficiency. To better understand this balance, the performance of numerical propagation methods is analyzed for LEO, GEO, and Molniya orbits. A numerical propagator consists of a set of differential equations describing perturbed orbital motion whose solution is approximated using a numerical integration method. This paper compares Cowell, Encke-time, Encke-beta, and Equinoctial Elements formulations over a range of integration function evaluations for a given set of perturbations and integrators. Function evaluations are shown to be a reasonable approximation of normalized computation time. …