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ASA & Ames Introduction: Overview of NASA and Ames Research Activities, with a special focus on NASA Aeronautics activities. All materials are overview in nature and have been presented previously in open forums.
The CloudSat satellite was launched from Vandenberg Air Force Base, in California, on April 28, 2006. It was launched with the CALIPSO satellite, a joint mission between the National Aeronautics and Space Administration (NASA) and the Centre National D'Etudes Spatiales (CNES). CloudSat and CALIPSO were designed to fly in formation with each other, to combine their complimentary scientific measurements. The two missions were maneuvered into the Earth Science Afternoon Constellation (A-Train) shortly after launch and have flown in formation together since then. Originally designed to fly for 22 months, the CloudSat satellite has far exceeded expectations. Inflight anomalies on CloudSat necessitated changes to both the daily concept of operations and formation flying operations with CALIPSO. In 2011, a severe battery anomaly restricted CloudSat science data collection and maneuverability to the sunlit portions of the orbit. In 2017, CloudSat suffered a reaction wheel failure, triggering the criteria established to exit the A-Train. CloudSat successfully exited the A-Train in early 2018, suspending formation flying and joint science observations with CALIPSO. The joint CloudSat/CALIPSO science team continued collaboration with discussions focused on resuming joint observations. As both satellites were aging and CALIPSO was nearing the exhaustion of satellite propellant, the decision was made to lower CloudSat to the CALIPSO graveyard orbit, to be joined by CALIPSO as soon as feasible. With NASA’s approval, CloudSat was maneuvered to the lower orbit over the course of several months in mid-2018. Once CloudSat was in place, and with approval from CNES, CALIPSO began the delicate dance of lowering their orbit and re-aligning the satellite ground tracks. CloudSat and CALIPSO resumed formation flying in the newly dubbed C-Train (CloudSat and CALIPSO) orbit in the Fall of 2018. The ingenuity of the CloudSat and CALIPSO teams made the concept of the C-Train a reality. This paper will discuss the decision processes and the operational challenges the CloudSat flight team faced while designing and implementing the C-Train.
The NGST primary mirror is anticipated to be a segmented deployable optic with segment size being in the range of 1 - 3 m depending on the details of the architecture. The secondary mirror will likely be a monolith similar in size to one of the primary mirror segments. Over the past 4 years the NGST program has initiated and implemented an aggressive lightweight cryogenic mirror technology program. The program was designed to challenge and excite the optical community in reaching a new standard in production of lightweight optics. The goal was to develop optics at less than 15 kg/sq m, operational at approx. 40 K and meeting the overall NGST observatory requirement for diffraction limited performance at 2 microns. In order to meet the NGST needs, technology efforts were initiated to investigate and develop mirrors in a variety of materials, which held promise for the program. The basic technology approaches have initially targeted the production of large mirrors in the 1.2 - 2.0 m diameter range (or side-to-side distance in the case of hexagonal optics). Although this size may not be the final size of an NGST primary mirror segment, it was felt that a 1.2 - 2.0 m optic would be of sufficient size to understand the mirror material and fabrication processes which drive the cost and schedule of mirror production. The ultimate goals of the technology program are both to demonstrate mirrors meeting, the NGST performance requirements, and to establish cost and schedule credibility for producing and implementing the mirrors for the NGST flight system. Establishing cost and schedule credibility is essential to NGST which is a cost capped mission, with past program experience demonstrating that the optics will be a large portion of the total cost of the program. The first two years of the program were dedicated to understanding; the various applicable materials, funding those materials to various levels of maturity and implementing the first large mirror procurement, the NGST Mirror System Demonstrator (NMSD), in order to establish a benchmark for the state-of-the-art in lightweight optics and to establish credibility that the goals of NGST could be achieved. The past two years of the program has seen major steps in the development of several mirror materials, which not only might have NGST applicability but could also support other programs for other customers. Additionally, a second large mirror procurement, the Advanced Mirror System Demonstrator (AMSD), has been implemented providing a focal point to complete the mirror technology development and lead ultimately to the production of mirrors that will fly on NEXUS (the NGST flight experiment- discussed below) and NGST. This talk will focus on the mirror technology developed over the past 4 years on the NGST program.
A synoptic of programmatic and technical lessons learned in the development of aerothermodynamic data bases for the X-33 and X-34 programs is presented in general terms and from the perspective of the NASA Langley Research Center Aerothermodynamics Branch. The format used is that of the aerothermodynamic chain, the links of which are personnel, facilities, models/test articles, instrumentation, test techniques, and computational fluid dynamics (CFD). Because the aerodynamic data bases upon which the X-33 and X-34 vehicles will fly are almost exclusively from wind tunnel testing, as opposed to CFD, the primary focus of the lessons learned is on ground-based testing.
The objectives of the Superboom Caustic Analysis and Measurement (SCAMP) Program were to develop and validate, via flight-test measurements, analytical models for sonic boom signatures in and around focal zones as they are expected to occur during commercial aircraft transition from subsonic to supersonic flight, and to apply these models to focus boom prediction of low-boom aircraft designs. The SCAMP program has successfully investigated sonic boom focusing both analytically and experimentally, while gathering a comprehensive empirical flight test and acoustic dataset, and developing a suite of focused sonic boom prediction tools. An experimental flight and acoustic measurement test was designed during the initial year of the SCAMP program, with execution of the SCAMP flight test occurring in May 2011. The current SCAMP team, led by Wyle, includes partners from the Boeing Company, Pennsylvania State University, Gulfstream Aerospace, Eagle Aeronautics, and Central Washington University. Numerous collaborators have also participated by supporting the experiment with human and equipment resources at their own expense. The experiment involved precision flight of a McDonnell Douglas (now Boeing) F-18B executing different maneuvers that created focused sonic booms. The maneuvers were designed to center on the flight regime expected for commercial supersonic aircraft transonic transition, and also span a range of caustic curvatures in order to provide a variety of conditions for code validations. The SCAMP experiment was designed to capture concurrent F-18B on-board flight instrumentation data, high-fidelity ground-based and airborne acoustic data, and surface and upper air meteorological data. Close coordination with NASA Dryden resulted in the development of new experimental instrumentation and techniques to facilitate the SCAMP flight-test execution, including the development of an F-18B Mach rate cockpit display, TG-14 powered glider in-flight sonic boom measurement instrumentation and "Where's the Focus?" (WTF) software for near-real time way-point computation accounting for local atmospherics. In May 2011, 13 F-18B flights were conducted during 5 flying days over a 2 week period. A densely populated 10,000 ft-long ground acoustic array with 125-ft microphone spacing was designed to capture pre-, focus, and post-focus regions. The ground-based acoustic array was placed in a nominally east-west orientation in the remote Cuddeback lakebed region, north of Edwards AFB. This area was carefully selected to avoid placing focused booms on populated areas or solar power facilities. For the SCAMP measurement campaign, approvals were obtained to temporarily extend the Black Mountain supersonic corridor northward by three miles. The SCAMP flight tests successfully captured 70 boom events, with 61 focus passes, and 9 calibration passes. Seventeen of the focus passes and three of the calibration passes were laterally offset; with the others being centerline flights. Airborne incoming sonic boom wave measurements were measured by the TG-14 for 10 of the F-18B flight passes including one maximum focus signature, several N-u combinations, several overlapped N-u signatures, and several evanescent waves. During the 27-month program, the SCAMP team developed a suite of integrated computer codes with sonic boom focusing predictive capabilities: PCBoom, Lossy Nonlinear Tricomi Equation Method (LNTE) and the Nonlinear Progressive wave Equation (NPE) method. PCBoom propagates the rays through the atmosphere and, in addition to legacy focus signature prediction based on the Gill-Seebass method, provides input source characteristics and propagation parameters to LNTE and NPE. LNTE, a Tricomi solver that incorporates atmospheric losses, computes the focus signature at the focus, and computes the focus signature in the vicinity of the focal zone, including the evanescent and post-focus zones. LNTE signature auralization from low-boom vehicle designs has been demonstrated in the NASA Langley Interior Effects Room (IER). The NPE has also been validated for use in prediction of focused ground boom signatures in sonic boom focal zones. The NPE formulation has the capability to incorporate atmospheric turbulence in the predictions. This has been applied to sonic boom propagation in the past. Prediction of turbulence effects on focal zone signatures was not, however, explored during the SCAMP program.
The goal of the research is to develop and test control strategies for a self-contained, free flying space robot. Such a robot would perform operations in space similar to those currently handled by astronauts during extravehicular activity (EVA). The focus of the work is to develop and carry out a program of research with a series of physical Satellite Robot Simulator Vehicles (SRSV's), two-dimensionally freely mobile laboratory models of autonomous free-flying space robots such as might perform extravehicular functions associated with operation of a space station or repair of orbiting satellites. The development of the SRSV and of some of the controller subsystems are discribed. The two-link arm was fitted to the SRSV base, and researchers explored the open-loop characteristics of the arm and thruster actuators. Work began on building the software foundation necessary for use of the on-board computer, as well as hardware and software for a local vision system for target identification and tracking.
In order to fly an occulter in formation with a telescope at the Sun-Earth L2 (SEL2) Libration Point, one must have a detailed understanding of the dy-namics that govern the restricted three body system. For initial purposes, a linear approximation is satisfactory, but operations will require a high-fidelity modeling tool along with strategic targeting methods in order to be successful. This paper focuses on the challenging dynamics of the transfer trajectories to achieve the relative positioning of two spacecraft to fly in formation at SEL2, in our case, the Wide-Field Infrared Survey Telescope (WFIRST) and a proposed Starshade. By modeling the formation transfers using a high fidelity tool, an accurate V approximation can be made to as-sist with the development of the subsystem design required for a WFIRST and Starshade formation flight mission.
In autonomous navigation, it is essential to obtain a three-dimensional (3D) description of the static environment in which the vehicle is traveling. For a rotorcraft conducting low-latitude flight, this description is particularly useful for obstacle detection and avoidance. In this paper, we address the problem of 3D position estimation for static objects from a monocular sequence of images captured from a low-latitude flying helicopter. Since the environment is static, it is well known that the optical flow in the image will produce a radiating pattern from the focus of expansion. We propose a motion analysis system which utilizes the epipolar constraint to accurately estimate 3D positions of scene objects in a real world image sequence taken from a low-altitude flying helicopter. Results show that this approach gives good estimates of object positions near the rotorcraft's intended flight-path.
Prognostics is the science of predicting the failure(s) of a component or a system and understanding how the performance will change in the event of a failure or degradation mechanism. With accurate predictions of possible failures, autonomous mitigative actions can be taken to correct/repair any issues or alert human operators of a failure threshold exceedance requiring condition-based maintenance. Although there is extensive research on failure predictions for a component or a system, there are significantly more opportunities to foray into failure predictions and prognostics for a system of systems such as an airspace consisting of multiple aircraft, a fleet of unmanned aerial vehicles, and a swarm of intelligent satellite systems. Failure prediction and mitigation are particularly important in autonomous systems such as satellite swarm systems that need effective resource management and minimal human interactions. Based on NASA's decadal survey, there is a clear need to prioritize the development of satellite swarm technology for studies of space physics and Earth science. The science community will propose future missions that return in-situ measurements from a 3-D (three-dimensional) volume of space, with relative spacecraft motion and inter-satellite baselines controlled according to the mission objectives. For such multi-spacecraft missions, it is required that ground operations resources do not scale with the number of satellites, thus compromising the swarm or leading to inefficiencies in resource allocation. Swarms of tens or hundreds of small satellites will require autonomy in attitude control, navigation and failure. Although significant research has been conducted in the areas of autonomous formation flying algorithms, less attention has been given to the development of resilient systems robust to failures.The focus of this research paper is the integration of model-based prognostics into the swarm dynamics control and decision-making algorithms. We simulate swarm management strategies for a subsystem failure to demonstrate the importance of failure predictions by comparing two cases: (i) no health information is provided to the system and utilized in the decision-making process and (2) system health information is obtained using prognostics and employed by the control system. One example scenario presented is for the GPS (Global Positioning System) system of an individual satellite to perform off-nominally due to increasing estimated error. In this scenario, the keep-out zone for that satellite would become more conservative, thereby decreasing the risk of collision. This is achieved via tuning the individual artificial repulsive functions assigned to each satellite.This paper is structured as follows. First we provide an overview of current swarm technology development, where we specifically use the term swarm to define multiple satellites flying in formation in similar orbits, with cross-link communication and station-keeping capabilities. Second, we give an introduction to the Swarm Orbital Dynamics Advisor (SODA), a tool that accepts high-level configuration commands and provides the orbital maneuvers required to achieve the prescribed formation configuration. Third, we provide the details of the model-based prognostics algorithm implementation in SODA. Finally, we present different case studies for potential component/subsystem failures and the swarm responses based with and without failure prediction information.
The investigation looked at the effects of the spatial layout and functionality of cockpit displays and controls on crew communication. Specifically, the study focused on the intra-cockpit crew interaction, and subsequent task performance, of airline pilots flying different configurations of a new electronic checklist, designed and tested in a high-fidelity simulator at NASA Ames Research Center. The first part of this proposal establishes the theoretical background for the assumptions underlying the research, suggesting that in the context of the interaction between a multi-operator crew and a machine, the design and configuration of the interface will affect interactions between individual operators and the machine, and subsequently, the interaction between operators. In view of the latest trends in cockpit interface design and flight-deck technology, in particular, the centralization of displays and controls, the introduction identifies certain problems associated with these modern designs and suggests specific design issues to which the expected results could be applied. A detailed research program and methodology is outlined and the results are described and discussed. Overall, differences in cockpit design were shown to impact the activity within the cockpit, including interactions between pilots and aircraft and the cooperative interactions between pilots.
The X-33, NASA's flagship for reusable space plane technology demonstration, is on course to begin the flights of the X-33 that will permit industry and government decisions that can lead to VentureStar(trademark) by the end of 2000. Lockheed Martin, NASA's partner in this effort, took the bold step in January 1999 to announce formation of VentureStar(trademark) LLC. This move provides the focus for firm business planning needed to enable the decision by the time X-33 flies in mid 2000. The X-33 program began by accepting the mandate that included two unprecedented and highly challenging goals: 1) demonstrate single stage to orbit technologies in flight and ground by the end of 2000 and 2) demonstrate a new government and industry management relationship working together with industry in the lead. Since the IAF 49th Congress in Melbourne, the major hardware elements of X-33 have been through their assembly and test. The flight liquid oxygen tank was the first major element to complete final assembly. The liquid hydrogen tanks are currently in final assembly and testing. The first flight tank has been delivered to vehicle assembly, the second tank and the flight engines are expected this month. The aerospike engine is an engine concept that has never been flown, but has been extensively ground tested. It will be flown for the first time on the X-33. Major X-33 flight hardware has been tested, delivered, and assembly of the vehicle is nearly complete. Construction of the prototype spaceport was completed in November 1998. The flight test program commencing in the summer of 2000. The decision to proceed with a Single Stage To Orbit as a commercial venture is expected in the fall of 2000.
The X-33, reusable space plane technology demonstrator is on course to begin the flights of the X-33 by the end of 2002 that will serve as a basis for industry and government decisions that could lead to VentureStar(Trademark). Lockheed Martin has placed the VentureStar LLC in it's Space Company and is now competing in an industry wide effort that will permit NASA to select a Second Generation RLV source by 2005. This move provides the focus for firm business planning needed to enable the decision by the time X-33 flies in mid 2002 and possibly with upgraded technologies a year or so later. The operations concept for the X-33 is an integration of launch vehicle and aircraft operations approaches. VentureStar is a Single Stage To Orbit (SSTO) and will therefore enable a new approach to Space Launch Operations that is more "aircraft like" and can produce substantially lower operating costs over current systems. NASA's initiatives over the past several years in Reusable Launch Vehicles (RLV) have had as a primary objective to demonstrate technologies that will result in significant reduction in costs of space access. Further, the end objective is to commercialize the development and operations of the next generation RLV. Hence, the X-33 and its operations demonstration is a major contributor to that next generation system.
The X-33, reusable space plane technology demonstrator is on course to begin the flights of the X-33 by the end of 2002 that will serve as a basis for industry and government decisions that could lead to VentureStar(Trademark). Lockheed Martin has placed the VentureStar(Trademark) LLC in it's Space Company and is now competing in an industry wide effort that will permit NASA to select a Second Generation RLV source by 2005. This move provides the focus for firm business planning needed to enable the decision by the time X-33 flies in mid 2002 and possibly with upgraded technologies a year or so later. Since the IAF 50th Congress in Amsterdam, most of the major hardware elements of X-33 have been through their assembly and test. The flight liquid oxygen tank was the first major element to complete final assembly. Aerospike Engine qualification testing has progressed successfully through its test objectives and the two flight engines are in preparation to be delivered to the Assembly Facility in Palmdale. All Thermal Protection System (TPS) metallic panels have completed qualification testing and have been delivered to Palmdale and all remaining TPS elements have been assembled and are ready for delivery. Flight Software and Avionics have been delivered and are in integration testing. In November 1999, the first graphite composite liquid hydrogen tank experienced a debond between the tank inner skin and the honeycomb core in testing. This tank had completed its third successful cryogenic and loads testing at MSFC. Replacement liquid hydrogen tanks have completed design and are in fabrication. The resulting delay from this change of design for the liquid hydrogen tank will be approximately two years.
An overview of the Starlight Mission is presented. Mission summary: June 2006 launch to heliocentric orbit; Nominal 6 month mission with option of additional 6 month extension; Validate autonomous formation flying system: range control to 10 cm bearing, control to 4 arcmin; Demonstrate formation flying optical interferometry.The original 3 spacecraft design did not fit the budget. 2 spacecraft concept demonstrates all key areas of formation flying interferometry. Collector flown on the surface of a virtual paraboloid, with combiner at the focus. It Gives a baseline of 125 m with a fixed delay of only 14 m.
Purpose: Assess In-Space NDE technologies and needs - current & future spacecraft. Discover & build on needs, R&D & NDE products in other industries and agencies. Stimulate partnerships in & outside NASA to move technologies forward cooperatively. Facilitate group discussion on challenges and opportunities of mutual benefit. Focus Areas: Miniaturized 3D Penetrating Imagers Controllable Snake-arm Inspection systems Miniature Free-flying Micro-satellite Inspectors
The PROPEL ("Propulsion using Electrodynamics") flight demonstration mission concept will demonstrate the use of an electrodynamic tether (EDT) for generating thrust, which will allow the propulsion system to overcome the limitations of the rocket equation. The mission concept has been developed by a team of government, industry, and academia partners led by NASA Marshall Space Flight Center (MSFC). PROPEL is being designed for versatility of the EDT system with multiple end users in mind and to be flexible with respect to platform. Previously, we reported on a comprehensive mission design for PROPEL with a mission duration of six months or longer with multiple mission goals including demonstration of significant boost, deboost, inclination change, and drag make-up activities. To explore a range of possible configurations, primarily driven by cost considerations, other mission concept designs have been pursued. In partnership with the NASA's Office of Chief Technologist (OCT) Game Changing Program, NASA MSFC Leadership, and the MSFC Advanced Concepts Office, a mission concept design was developed for a near-term EDT propulsion flight validation mission. The Electrodynamic Tether Propulsion Study (ETPS) defined an EDT propulsion system capable of very large delta-V for use on future missions developed by NASA, DoD, and commercial customers. To demonstrate the feasibility of an ETPS, the study focused on a space demonstration mission concept design with configuration of a pair of tethered satellite busses, one of which is the Japanese H-II Transfer Vehicle (HTV). The HTV would fly its standard ISS resupply mission. When resupply mission is complete, the ISS reconfigures and releases the HTV to perform the EDT experiment at safe orbital altitudes below the ISS. Though the focus of this particular mission concept design addresses a scenario involving the HTV or a similar vehicle, the propulsion system's capability is relevant to a number of applications, as noted above. The ETPS builds on prior work on long-life, failure-resistant, conducting tethers and includes an instrument suite with demonstrated heritage capable of performing necessary diagnostics to measure performance against predictions for a given system size (to be determined) and boost rate. Mission designs in other configurations and launch vehicle options are being developed such that the system can be demonstration should a flight opportunity be identified. We will report on past and ongoing implementation options for PROPEL.
The Heliophysics Environmental and Radiation Measurement Experiment Suite (HERMES) is a set of four instruments that will fly on the Lunar Gateway, an orbital outpost which will support Artemis lunar operations. HERMES will focus on understanding the causes of space-weather variability as driven by the Sun and modulated by the magnetosphere. In this talk, we will discuss the open source approach of the HERMES Science Operation Center (SOC) team being implemented in a number of Python packages which all work together. We will describe the core package which contains Python interfaces for the loading, calibrating, plotting, validating, and saving of measurement data through Common Data Format (CDF) files making use of pycdf provided by spacepy. Each instrument also has a Python package developed using a package template and will provide specific calibration and processing functionality to each instrument. The packages make extensive use of the scientific Python ecosystem and maintain compatibility with PyHC standards. The abstraction of intricate, high heritage data formats, such as CDF files, in Python enables easier analysis and opens doors for greater participation in heliophysics science.
The NASA F/A-18 High Alpha Research Vehicle (HARV) has been the flight test bed of a focused technology effort to significantly increase maneuvering capability at high angles of attack. Development and flight test of control law design methodologies, handling qualities metrics, performance guidelines, and flight evaluation maneuvers are described. The HARV has been modified to include two research control effectors, thrust vectoring, and actuated forebody strakes in order to provide increased control power at high angles of attack. A research flight control system has been used to provide a flexible, easily modified capability for high-angle-of-attack research controls. Different control law design techniques have been implemented and flight-tested, including eigenstructure assignment, variable gain output feedback, pseudo controls, and model-following. Extensive piloted simulation has been used to develop nonlinear performance guide-lines and handling qualities criteria for high angles of attack. This paper reviews the development and evaluation of technologies useful for high-angle-of-attack control. Design, development, and flight test of the research flight control system, control laws, flying qualities specifications, and flight test maneuvers are described. Flight test results are used to illustrate some of the lessons learned during flight test and handling qualities evaluations.