Engineering Papers⌕ Search

Engineering topics

Guit, William J.

Publications and source records attributed to Guit, William J..

12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

The Legacy and Future of the International Earth Science Constellation (ESC)

The most recent Decadal Survey placed high value on continuing constellation science. The ESC has evolved by seeing new missions joining and old missions retiring. Most recently, GCOM-W1, Landsat-8, and OCO-2 joined during 2012-2014. Landsat-9 is set to join in 2020. Each new mission provides new and improved suite of sensors. The new sensors also benefit both from the multitude of other existing on-orbit sensors as well as from the long-term cross-calibrated climate observations from the sensors that preceded them. At the same time, existing missions leave the constellation due to low fuel reserves or aging spacecraft subsystems. For example, CloudSat and CALIPSO left the ESC orbits in 2018, although they plan to continue making coordinated science observations at their new lower altitudes. This ESC evolution is expected to continue and this paper will discuss the opportunities for other new missions to join the ESC.

afternoon constellation↗
NASA NTRS2018

To Maneuver or Not to Maneuver that Is the Question

The Earth Observing System (EOS) missions, Terra, Aqua, and Aura, are NASA's flagship Earth Science missions and are part of the International Earth Science Constellation (ESC). The ESC is composed of satellites that fly in the Afternoon Constellation (also known as the A-Train) and the Morning Constellation. All missions fly in 705-kilometer altitude, polar sun-synchronous orbits that are inclined 98.2 degrees. NASA's key operational priorities are to keep the satellites safe and maintain open and cooperative communications between all member missions. As the NASA Mission Director for the EOS Aqua and Aura satellites since their respective launches in 2002 and 2004, Mr. Guit has been responsible for the safety and operations of the satellites as they have successfully operated in the A-Train. Mr. Guit will present a recent EOS Aqua debris avoidance maneuver planning and execution challenge, how it was overcome, and how it affected the other member missions of the A-Train constellation.

Orbital debris↗
NASA NTRS2018

Leverage Your Science Data Return by Flying with the International Earth Science Constellation (ESC)

Constellations have proven to be an effective and efficient way to acquire earth science data. By flying together, sensors on all satellites in a constellation take measurements of the same air, water, or land mass at essentially the same time. The sensors form a single "virtual satellite". The key to making a constellation effective and efficient is keeping the operations as independent as possible in order to minimize the operational burden and costs. The Earth Science Constellation (ESC) has been successful on all counts and continues to welcome new missions to continue its 18+ year record of coincidental earth science observations. The ESC also serves as a model for future constellation designs. This paper describes the ESC and its evolution from its initial launches in 1999 through the present and how new missions might benefit from joining the ESC.

Morning Constellation; Afternoon Constellation; Ea↗
NASA NTRS2018

Leverage Your Science Data Return by Flying with the International Earth Science Constellation (ESC)

Constellations have proven to be an effective and efficient way to acquire earth science data. By flying together, sensors on all satellites in a constellation take measurements of the same air, water, or land mass at essentially the same time. The sensors form a single "virtual satellite". The key to making a constellation effective and efficient is keeping the operations as independent as possible in order to minimize the operational burden and costs. The Earth Science Constellation (ESC) has been successful on all counts and continues to welcome new missions to continue its 18+ year record of coincidental earth science observations. The ESC also serves as a model for future constellation designs. This paper describes the ESC and its evolution from its initial launches in 1999 through the present and how new missions might benefit from joining the ESC.

leverage data↗
NASA NTRS2017

Relevance of the American Statistical Society's Warning on P-Values for Conjunction Assessment

On March 7, 2016, the American Statistical Association (ASA) issued an online editorial paper on the "context, process, and purpose of p-values." According to the paper, "the statement articulates in non-technical terms a few select principles that could improve the conductor interpretation of quantitative science, according to widespread consensus in the statistical community." This "consensus" statement was accompanied by 21 "commentaries" expressing a diversity of opinions among the panel of experts ASA convened. In the present work, we express our view that the ASA p-value warning has relevance to the space object Conjunction Assessment (CA) community.

p-values↗
NASA NTRS2017

Aqua Spacecraft Status Extended Mission

This will be presented at the Earth Science constellation Mission Operations Working Group meeting June 13-15, 2017 to discuss Aqua spacecraft status extended mission.

Aqua↗
NASA NTRS2016

International Earth Science Constellation (ESC) Introduction

This is the Welcome and Introduction presentation for the International Earth Science Constellation (ESC) Mission Operations Working Group (MOWG) meeting held in Albuquerque NM from September 27-29. It contains an org chart, charter, history, significant topics to be discussed, AquaAura 2017 inclination adjust maneuver calendar, a-train long range plans, upcoming events, and action items.

ECS↗
NASA NTRS2016

International Earth Science Constellations (ESC) Introduction

This presentation will discuss NASA HQ perspective, current state of the mission, Landsat 7 and Terra exit plans, long term plans for all mission, CARA updates, Spring 2016 IAM series plans and current status, CCS future release plans, and results of covariance calculation meetings.

Afternoon Constellation↗
NASA NTRS2016

EOS Aqua Mission Status at Earth Science Constellation MOWG Meeting @ LASP April 13, 2016

This presentation reflects the EOS Aqua mission status, spacecraft subsystem summary, recent and planned activities, inclination adjust maneuvers, propellant usage and lifetime estimate, orbital maintenance maneuvers, conjunction assessment high interest events, ground track error, spacecraft orbital parameters trends and predictions.

Aqua mission status↗
NASA NTRS2015

EOS Aura Mission Status

This PowerPoint presentation will discuss EOS Aura mission and spacecraft subsystem summary, recent and planned activities, inclination adjust maneuvers, propellant usage lifetime estimate. Eric Moyer, ESMO Deputy Project Manager-Technical (code 428) has reviewed and approved the slides on April 30, 2015.

propellant usage↗