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NASA NTRS2010

The NASA Constellation Program Procedure System

NASA has used procedures to describe activities to be performed onboard vehicles by astronaut crew and on the ground by flight controllers since Apollo. Starting with later Space Shuttle missions and the International Space Station, NASA moved forward to electronic presentation of procedures. For the Constellation Program, another large step forward is being taken - to make procedures more interactive with the vehicle and to assist the crew in controlling the vehicle more efficiently and with less error. The overall name for the project is the Constellation Procedure Applications Software System (CxPASS). This paper describes some of the history behind this effort, the key concepts and operational paradigms that the work is based upon, and the actual products being developed to implement procedures for Constellation

Phillips, Robert G.↗

NASA NTRS2011

Understanding Geospace on a Grand Scale: The Global Ionoshphere/Thermosphere Constellation

We present the concept of a constellation of polar orbiting satellites equally spaced in longitude (local time) to systematically sample both the neutral and ionzed gas components of the Earth in circular orbits near 350 km, including their density, temperature, and velocities. The instrumentation would include techniques to measure the height of the ionospheric "F-peak" and its variations along the orbit. The number of satellites (l2? 24? 48?) and their configuration would be determined from modeling analysis and expected geophysical phenomena, including their drivers and characteristic time scales. Together with imaging data from separate satellites, the array of satellites with in situ probes would be expected to provide a new picture of (1) high latitude electrodynamics and atmospheric processes and associated coupling with magnetospheric mass and momentum input, (2) the response of the global ionosphere and thermosphere to magnetic storms, and (3) global neutral wind circulation patterns, neutral density structure, tides, planetary waves, and gravity waves. The comprehensive measurements gathered by the IT-Constellation envisioned here would provide a major leap forward in each of these areas, addressing global physical processes and providing fundamental, new knowledge of Geospace. In particular, by its very nature, the constellation addresses "system science", revealing how the ionosphere-thermosphere connects globally to the magnetosphere above and the troposphere below. We present this concept as the next logical step in observing the "whole" space environment using in situ probes in conjunction with imagers. We invite modelers to not only comment on this concept but also to become actively engaged in helping to define it.

Pfaff, Robert↗

NASA NTRS2012

Simulating the Liaison Navigation Concept in a Geo + Earth-Moon Halo Constellation

Linked Autonomous Interplanetary Satellite Orbit Navigation, or LiAISON, is a novel satellite navigation technique where relative radiometric measurements between two or more spacecraft in a constellation are processed to obtain the absolute state of all spacecraft. The method leverages the asymmetry of the gravity field that the constellation exists in. This paper takes a step forward in developing a high fidelity navigation simulation for the LiAISON concept in an Earth-Moon constellation. In particular, we aim to process two-way Doppler measurements between a satellite in GEO orbit and another in a halo orbit about the Earth-Moon L1 point.

Linked Autonomous Interplanetary Satellite Orbit N↗

NASA NTRS2015

On the Feasibility of Monitoring Carbon Monoxide in the Lower Troposphere from a Constellation of Northern Hemisphere Geostationary Satellites (PART 1)

By the end of the current decade, there are plans to deploy several geostationary Earth orbit (GEO) satellite missions for atmospheric composition over North America, East Asia and Europe with additional missions proposed. Together, these present the possibility of a constellation of geostationary platforms to achieve continuous time-resolved high-density observations over continental domains for mapping pollutant sources and variability at diurnal and local scales. In this paper, we use a novel approach to sample a very high global resolution model (GEOS-5 at 7 km horizontal resolution) to produce a dataset of synthetic carbon monoxide pollution observations representative of those potentially obtainable from a GEO satellite constellation with predicted measurement sensitivities based on current remote sensing capabilities. Part 1 of this study focuses on the production of simulated synthetic measurements for air quality OSSEs (Observing System Simulation Experiments). We simulate carbon monoxide nadir retrievals using a technique that provides realistic measurements with very low computational cost. We discuss the sampling methodology: the projection of footprints and areas of regard for geostationary geometries over each of the North America, East Asia and Europe regions; the regression method to simulate measurement sensitivity; and the measurement error simulation. A detailed analysis of the simulated observation sensitivity is performed, and limitations of the method are discussed. We also describe impacts from clouds, showing that the efficiency of an instrument making atmospheric composition measurements on a geostationary platform is dependent on the dominant weather regime over a given region and the pixel size resolution. These results demonstrate the viability of the "instrument simulator" step for an OSSE to assess the performance of a constellation of geostationary satellites for air quality measurements.

GEOS-5↗

NASA NTRS2017

First Time-Resolved Observations of Precipitation Structure and Storm Intensity with a Constellation of Smallsats (TROPICS) Mission Applications Workshop Summary Report

The National Aeronautics and Space Administration (NASA) Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of SmallSats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave sounders but with unprecedented temporal resolution. TROPICS is a cost-capped ($30 million) Venture-class mission funded by the NASA Earth Science Division (ESD) and led by principal investigator Dr. William Blackwell from the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). The mission is comprised of a constellation of six, three-unit (3U) Cube-Sats (approximately 10 by 10 by 34 centimeters), each hosting a 12-channel passive microwave spectrometer based on the Micro-sized Microwave Atmospheric Satellite 2 (MicroMAS-2) developed at MIT LL. TROPICS will provide imagery at frequencies near 91 and 205 gigahertz, temperature sounding near 118 gigahertz, and moisture sounding near 183 gigahertz. Spatial resolution at nadir will be around 27 kilometers for temperature and 17 kilometers for moisture and precipitation with a swath width of approximately 2,000 kilometers. Both the spatial resolution and swath width are similar to the Advanced Technology Microwave Sounder (ATMS) that is being flown as part of the Suomi National Polar-Orbiting Partnership and will fly starting in 2017 on the National Oceanic and Atmospheric Administration (NOAA) Joint Polar Satellite System (JPSS). In addition, TROPICS meets many of the requirements outlined in the 2007 Decadal Survey for the Precision and All-Weather Temperature and Humidity mission, which was originally envisioned as a microwave instrument in geostationary orbit. TROPICS enables temporal resolution similar to geostationary orbit but at a much lower cost, demonstrating a technology that could impact the design of future Earth-observing missions. The satellites for the TROPICS mission are slated for delivery to NASA in 2019 for launches planned no earlier than 2020. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity.

applied scienc↗

NASA NTRS2018

Options for the Continuing Evolution of the Earth Science Constellation

The International Earth Science Constellation (ESC) continues to evolve and has come a long way since the official formation in 1990. This poster describes the successful operations and the challenges and options being considered for the future evolution of the constellation. Space agencies face significant challenges in order to extend the current observation capabilities and long-term climate record from the Earth Science Constellation.

Machado, Michael↗

NASA NTRS2018

Trade-Space Analysis Tool for Designing Constellations (TAT-C)

While there is growing interest in implementing future NASA Earth Science missions as Distributed Spacecraft Missions (DSMs), there are currently no tool to help in the design of DSMs. The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. Our Trade-space Analysis Tool for Constellations (TAT-C) allows to investigate questions such as: "Which type of constellations should be chosen? How many spacecraft should be included in the constellation? Which design has the best cost/risk value?" This paper provides a description of the TAT-C tool and its components.

Image Processing↗

NASA NTRS2016

TAT-C: A Trade-Space Analysis Tool for Constellations

Under a changing technological and economic environment, there is growing interest in implementing future NASA Earth Science missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: Which type of constellations should be chosen? How many spacecraft should be included in the constellation? Which design has the best costrisk value? This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI and formulating Trade-space Search Requests for the Trade-space Search Iterator, which in collaboration with the Orbit Coverage, Reduction Metrics, and Cost Risk modules generates multiple potential architectures and their associated characteristics. UI will include Graphical, Command Line and Application Programmer Interfaces to respond to the demands of various levels of users expertise. Science inputs are grouped into various mission concepts, satellite specifications, and payload specifications, while science outputs are grouped into several types of metrics - spatial, temporal, angular and radiometric. Orbit Coverage leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data that are passed to Reduction Metrics. Then, for each architecture design, Cost Risk will provide estimates of the cost and life cycle cost as well as technical and cost risk of the proposed mission. Additionally, the Knowledge Base module is a centralized store of structured data readable by humans and machines. It will support both TAT-C analysis when composing new mission concepts from existing model inputs, and TAT-C exploration when discovering new mission concepts by querying previous results.

Science Data Processing↗

NASA NTRS2018

Magnetospheric Constellation: Leveraging Space 2.0 for Big Science

Earth's magnetosphere is a large magnetic cavity formed through the interaction of the solar wind and Earth's intrinsic magnetic field. Solar wind energy enters this cavity through a boundary - the magnetopause - separating Earth's field from the solar wind. This energy leads to many forms of "space weather", including the aurora, geomagnetic storms, and energization of the Van Allen radiation belts. Despite decades of research, we still do not understand the extent of dayside reconnection sites, nor do we have a quantifiable understanding of how much energy enters the magnetosphere during different solar wind conditions - necessary for space weather prediction. On the nightside, impulsive flows at various spatial and temporal scales occur frequently during storms and substorms, and couple to the ionosphere through still unresolved physical mechanisms. Because the magnetosphere is so large, it has been understood since the dawn of the space age that a full understanding of this complex region could only be achieved with a large fleet of in situ spacecraft. NASA has studied one such constellation, the socalled "Magnetospheric Constellation" (MagCon), since the1990's, but it is deemed too expensive to implement using traditional approaches. The CubeSat/ SmallSat revolution represents a fundamental disruption to traditional mission architectures, and in this paper I will discuss how, by leveraging innovation in spacecraft subystems, advanced manufacturing, and access to space, we can finally realize this long-term vision of exploration and discovery. The proposed modular approach, utilizing rideshare and propulsive ESPAs, would also enable worldwide participation in the mission, and is applicable to any constellation mission, including Earth Science missions.

Kepko, Emil Larry↗

NASA NTRS2021

Second Time-Resolved Observations of Precipitation Structure and Storm Intensity With a Constellation of Smallsats (TROPICS) Mission Applications Workshop

The NASA Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave (PMW) sounders but with unprecedented temporal resolution (Mission Website).1 TROPICS is a cost-capped ($30.2 million), Venture-class mission funded by the NASA Earth Science Division (ESD) and led by Principal Investigator Dr. William Blackwell from the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). The mission consists of a constellation of six, three-unit (3U) CubeSats (approximately 10×10×34 cm), each hosting a 12-channel PMW spectrometer based on the Micro-sized Microwave Atmospheric Satellite-2 (MicroMAS-2) developed at MIT LL, but with a substantially improved design. TROPICS will provide imagery near 91 and 205 GHz, temperature sounding near 118 GHz, and moisture sounding near 183 GHz. Spatial resolution at nadir will be around 27 km for temperature and 17 km for moisture and precipitation with a swath width of approximately 2,000 km from a 550-km orbit altitude. Both the spatial resolution and swath width are similar to the Advanced Technology Microwave Sounder (ATMS) that is being flown as part of the Suomi National Polar-orbiting Partnership (SNPP) and National Oceanic and Atmospheric Administration (NOAA) Joint Polar Satellite System (JPSS). In addition, TROPICS meets many of the requirements outlined in the 2007 Decadal Survey for the Precision and All-Weather Tempera-ture and Humidity (PATH) mission, which was originally envisioned as a microwave instrument in geostationary orbit. TROPICS enables temporal resolution approaching that of geostationary orbit but at a much lower cost, demonstrating a technology that could impact the design of future Earth-observing missions. The satellites for the TROPICS mission were delivered to NASA in 2019 for launches planned in the 2021–2022 timeframe. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity.

remote sensing↗

NASA NTRS2022

Distributed Observation Allocation for a Large-Scale Constellation

Increased space and ground sensing is enabling dramatic new measurements of a wide range of Earth Science and Applied Earth Science phenomena, including: volcanism, flooding, wildfires, and weather. Large scale observations constellations of hundreds of assets already exist (e.g. Planet) with several constellations with 10,000’s of assets planned. New challenges exist to rapidly assimilate available data and to optimize measurements (e.g. direct assets) to best observe these complex and dynamic spatiotemporal phenomena. We describe automated centralized and distributed Artificial Intelligence methods for allocating observations within a constellation.

Harrod, Ryan↗

NASA NTRS2022

Distributed Observation Allocation for a Large-Scale Constellation

Harrod, Ryan↗

NASA NTRSDate not supplied

Lessons Learned on Mega-Constellation Deployments and Impact to Space Domain Awareness

The breakneck expansion of multi-payload launches in low Earth orbit (LEO) has seen significant escalation over the last three years in the Space Domain Awareness (SDA) enterprise. The uptick in satellite deployment frequency, gradation of mega-constellation deployments utilizing electric propulsion, and surge in metric observation density from the Space Surveillance Network (SSN) have driven major system enhancements to ensure spaceflight safety. Beginning with the launch phase, new tactics, software, and procedures have been developed over the last few years to optimize the tasking of the SSN and ensure custody of all recently launched satellites that are added to the space catalog. Ensuring appropriate tasking levels were pivotal during the satellite separation phase, which necessitated updates to the mission systems for improved delineation between clustered satellites in a short window of time. The improved incorporation of utilizing satellite owner/operator-provided ephemeris coupled with critical code improvements have revolutionized how we maintain custody of Earth orbiting objects. The exponential population growth of Low-Earth orbiting satellites have also increased the quantity of Conjunction Data Messages sent out to partners such as the Trajectory Operations Group (TOPO) in Johnson Space Center. We will discuss the need for continued collaboration between the National Aeronautics and Space Administration (NASA) and other mega-constellation satellite operators to safeguard human spaceflight operations. Lastly, we will discuss how mega-constellations are driving best practices for safe operations across the space community.

Christian Ramos↗

NASA NTRS2025

Localization of Ad-Hoc Lunar Constellations in Communication Failure Modes for Distributed Spacecraft Autonomy

As Lunar missions increase in complexity, inspired by NASA’s Artemis Program, they will require reliable and sufficient Position, Navigation, and Timing (PNT) capability to support the upcoming Lunar users. The navigation service should also be compatible with the smaller platforms, like CubeSats, being sent by the public and private sectors. A non-dedicated, ad-hoc Lunar navigation constellation can provide PNT services on-demand using the non-dedicated swarm assets. Swarm members cooperatively and autonomously localize themselves with minimal interaction from Earth, freeing up valuable bandwidth and ground segment resources. The autonomous localization of Lunar constellations utilizes neighbor two-way intersatellite link (ISL) measurements in a distributed extended Kalman filter (DEKF) system to minimize operating costs. Because the decentralized Lunar PNT system relies on relay communication amongst the agents, network failures or loss of assets among ad-hoc Lunar constellations may impact localization performance. This study presents an evaluation of localization performance under increasing levels of network degradation. A simulation of an ad-hoc Lunar PNT swarm is augmented to include system faults and the impacts of intermittent and permanent failures on localization performance are evaluated. We investigate three potential causes of network degradation: single spacecraft loss, multiple spacecraft loss, and antenna failure. The numerical assessments from the simulation show that the LPNT system under study, based on an autonomous decentralized concept of operation, is highly robust and resilient to communication failures. Minor faults, such as single spacecraft loss, solar interference, technical malfunctions, message delays, and antenna outages, have minimal impact on state estimation, with only a 4.47% and 3.75% degradation in median position error for assets and a representative ground user, respectively, compared to an ideal communication scenario. However, major faults, such as hardware failures or meteor strikes leading to the loss of multiple spacecrafts, are more concerning. The permanent loss of three spacecraft results in a more severe performance degradation, with median position error increasing by 23.3% for assets and 11.7% for a representative ground user, despite the Lunar PNT system remaining functional.

Yeji Kim↗

NASA NTRSDate not supplied

Aqua A-Train Constellation Exit and End of Mission Plan

The Aqua Mission Director has requested the Aqua Flight Operations Team present the current status of the Aqua Constellation Exit Manaeuver (CEM) and End of Mission Plan (EMOP) to the Earth Science Constellation Mission Operations Working Group (MOWG) meeting planned as a virtual meeting from September 29 - October 2, 2020.

Earth Science Constellation Mission Operations Wor↗

NASA NTRS1999

Sattelite-Constellation Design

The importance of communications satellite constellations cannot be overstated. In one fell swoop, such a constellation can provide an under developed region without a modern communication infrastructure with an instant modern communications network.

constellation design communications satellite spac↗

NASA NTRS2005

Coverage and control of constellations of elliptical inclined frozen lunar orbits

A great deal of scientific interest exists regarding the permanently shadowed craters near the poles of the Moon where there may be frozen volatiles. These regions, particularly the Moon's South Pole, have been proposed for extensive robotic and human exploration. Unfortunately, they are typically not in view of Earth, and would require some form of communication relay to facilitate exploration via robotic and/or human missions. One solution for such a relay is a long-lived constellation of lunar telecommunication orbiters providing focused coverage at the pole of interest. Robust support requires this coverage to be continuous, redundant, and, in order to minimize costs, this constellation should consist of 3 satellites or fewer.

lunar constellation design↗

NASA NTRS2008

Workforce Transition Strategy: Initial Report. Space Shuttle and Constellation Workforce Focus

The transition from Space Shuttle to Constellation over the next few years provides a rare opportunity to reinvigorate the Nation's space exploration capabilities. During that time, NASA's greatest challenge and top priority will be to safely fly out the Space Shuttle manifest, complete assembly of the International Space Station (ISS), and honor commitments to our international partners prior to retiring the Shuttle in 2010, all while developing the new Constellation space systems and preparing them for flight as soon as possible after the Shuttles last mission.

Workforce Transition Strategy↗