APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

Chasing the Moon’s Shadow

Explanation: Chasing the shadow of a New Moon, NASA’s WB-57F high altitude research aircraft took to the skies off the coast of Iceland on August 12 to observe a total solar eclipse. At 50,000 feet the aircraft was piloted along the precisely determined path of totality to maximize its time in the Moon’s shadow. A suite of high-resolution cameras on board was able to record eclipse data from above the clouds, dust, and atmospheric water vapor that interfere with observations made closer to the ground. This view from the cockpit, taken from an inflight video, captures the solar corona emerging at the beginning of totality. The sky appears dark in the shadow of the Moon. Venus is shining left of center in the video frame, while Jupiter and Mercury are just visible to the right of the eclipsed Sun. But the sky is bright along the distant horizon below, beyond the reach of the Moon’s shadow.

APOD’s main NASA site is moving: From apod.nasa.gov to science.nasa.gov/apod
Tomorrow’s picture: enhancing Pluto

Date	September 5, 2026
Credit:	NASA
Authors & editors:	Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, Keighley Rockcliffe
A service of:	ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U.

Source: science.nasa.gov

The fire department at NASA’s Ames Research Center in California’s Silicon Valley will perform training on the Moffett Federal Airfield beginning Tuesday, Sept. 8 through Friday, Sept. 11. The training will involve the use of a propane-fueled aircraft fire simulator and be conducted from 8 a.m. to 8 p.m. PDT.

Because the aircraft simulator is fueled by propane, very little smoke should be produced during the controlled training fires. However, flames may be visible to drivers on U.S. Highway 101. The training is intended to prepare Ames’ first responders to respond to a variety of realistic aircraft firefighting scenarios.

For more information about NASA’s Ames Research Center, visit:

http://www.nasa.gov/ames

-end-

Jeanne Neal
Ames Research Center, Silicon Valley
650-604-4789
[email protected]

To receive local NASA Ames news, email [email protected] with “subscribe” in the subject line. To unsubscribe, email the same address with “unsubscribe” in the subject line.

Source: www.nasa.gov

NASA will host a virtual webinar at 2 p.m. EDT on Friday, Oct. 2, titled “The RS-25 Engine and the Future of Artemis Missions: An Accessible Webinar for the Blind and Low-Vision Community.” This webinar is open to the public, however it is tailored specifically for a blind and low-vision audience.

The webinar will last about two hours and include an audio-described video of an RS-25 engine test, a Q&A session with an Artemis engineer, and a panel about accessibility in space and science. The event will be hosted on the Zoom platform. 

Participants in the session include:

• Dr. Kimberly Arcand, visualization scientist, NASA’s Chandra X-ray Observatory
• Josh Greiner, test director, NASA’s Stennis Space Center in Bay St. Louis, Mississippi
• Dr. Craig Moore, materials engineer, NASA’s Marshall Space Flight Center in Huntsville, Alabama
• Dr. Robert Shelton, lead simulation engineer, NASA’s Johnson Space Center in Houston
• Christine Malec, freelance writer and consultant

Those interested in attending the webinar must RSVP using this form by Friday, Sept. 25. Any questions can be directed to [email protected]. The details of the webinar will be emailed to registrants in the days leading up to the event.

NASA’s Artemis program will send astronauts on increasingly difficult missions to explore the Moon and establish a Moon Base on the lunar surface. For additional information on the Artemis missions, visit:

https://www.nasa.gov/artemis

Source: www.nasa.gov

On Wednesday, June 17, skywatchers across the United States—and parts of Canada—enjoyed a rare event: a daytime lunar occultation of Venus. A lunar occultation occurs when the Moon moves directly in front of another celestial object from our viewpoint on Earth, briefly hiding it from sight.

This time, the Moon slipped in front of Venus for the first of three occultations happening this year, creating a striking daylight moment for those who caught it. If you missed it, there will be two more opportunities to see Venus disappear behind the Moon in 2026: Sept. 14, visible from parts of Asia, Africa, Europe, and western Russia; and Nov. 7, visible from southern South America.

Source: www.nasa.gov

APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

Nā ʻUhane Māhoe Huki Pū i ke Ola

Explanation: Nā ʻUhane Māhoe Huki Pū i ke Ola, is the Hawaiian name given to this image of a pair of spiral galaxies locked in a mutual gravitational embrace. Some 200 million light-years distant toward the high flying constellation Pegasus their spectacular, galactic scale merger is captured in sharp detail in the image from the 8.1 meter Gemini North telescope on Maunakea, Hawai‘i. The galaxy pair, known as NGC 7253 and Arp 278, was chosen as a target, researched, and given an Hawaiian name by high school students in the joint Gemini Observatory and University of Hawaiʻi Project Hōkūlani internship program. The name translates to “The Twin Spirits Pulling Together Creating Life”. That’s both culturally and astronomically appropriate for galaxy collisions that trigger a cosmic maelstrom of star formation from galactic reservoirs of elemental building blocks of life. These merging galaxies are found within a region of Pegasus identified as the Hawaiian navigational constellation Ka Lupe o Kawelo.

APOD’s main NASA site is moving: From apod.nasa.gov to science.nasa.gov/apod
Tomorrow’s picture: chasing shadows

Date	September 4, 2026
Credit:	Image Credit: International Gemini Observatory / NOIRLab/NSF/AURA Image Processing: J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), D. de Martin & M. Zamani (NSF NOIRLab)
Authors & editors:	Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, Keighley Rockcliffe
A service of:	ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U.

Source: science.nasa.gov

When hurricane forecasters released their seasonal outlooks in spring 2026, the El Niño brewing in the Pacific contributed to predictions of below-normal activity in the Atlantic basin but above-normal activity in the northeastern and central Pacific basins. In early September, near the climatological peak of hurricane season, those spring outlooks were on target, with the eastern Pacific buzzing with activity and the Atlantic notably quiet.

As of September 3, the Northeast Pacific had produced 15 named storms and six hurricanes, well above the norm for that point in the season. The Atlantic basin, meanwhile, laboring under unfavorable wind shear conditions, had produced just five named storms and no hurricanes. El Niño typically enhances hurricane activity in the eastern and central Pacific basins because of the unusually warm water temperatures it brings to those parts of the ocean. It tends to suppress hurricane activity in the Atlantic basin by shifting large-scale circulation patterns in a way that makes it harder to sustain storms there.

At 1:14 p.m. Pacific Daylight Time (20:14 Universal Time) on September 1, NASA’s EPIC (Earth Polychromatic Imaging Camera) on the DSCOVR (Deep Space Climate Observatory) satellite captured an image of three tropical cyclones churning simultaneously in the Pacific, along with one in the Atlantic. A band of clouds and thunderstorms associated with the Intertropical Convergence Zone (ITCZ) is visible to the south of the storms. The spacecraft was nearly 1 million miles from Earth and just shy of 93 million miles from the Sun when the image was acquired.

The trio of storms in the Pacific were Lowell, Karina, and Marie. Of the three, Lowell became the strongest, with winds reaching category 5 strength for several hours on September 2. Around the same time, Karina, spinning a few thousand kilometers to the east, achieved category 4 strength, a rare case of category 4 and 5 hurricanes occurring simultaneously in the area. Marie, spinning southwest of Baja California, was still a tropical storm when the image was acquired but was strengthening as it moved northwest.

In the Atlantic, Tropical Storm Edouard was visible to EPIC over Louisiana and Texas, shortly after the short-lived storm made landfall. It brought torrential rains and strong winds that downed trees and power lines. Some areas received 15 to 24 inches (38 to 61 centimeters) of rain, according to National Weather Service meteorologists.

As of September 3, the Atlantic basin’s total accumulated cyclone energy (ACE) index was 4.4, about 9 percent of normal for that date, according to statistics compiled by Colorado State University meteorologists. Meanwhile, the Northeast Pacific basin’s ACE was 130, about 50 percent above normal. The ACE index incorporates both the intensity and longevity of storms, making it easier to compare individual storms and seasons.

Several NASA Earth-observing platforms provide data that can aid in emergency preparedness before landfall and damage assessment and response afterward. Use the “Events” tab on NASA’s Worldview browser to track current hurricanes and explore related NASA data products.

NASA Earth Observatory image by Lauren Dauphin, using data from DSCOVR EPIC. Story by Adam Voiland.

Downloads

September 1, 2026

JPEG (1.49 MB)

References & Resources

• AccuWeather (2023, June 6) Experts say this metric is a more reliable way to quantify the true strength of hurricane season. Accessed September 3, 2026.
• Colorado State University (2026, September 3) Northern Hemisphere Tropical Cyclone Activity for 2026. Accessed September 3, 2026.
• NASA Earthdata, Hurricanes. Accessed September 3, 2026.
• NASA, El Niño. Accessed September 3, 2026.
• NASA Space Place (2025, April 3) How Do Hurricanes Form? Accessed September 3, 2026.
• National Hurricane Center (2026, September 3) Top News of the Day. Accessed September 3, 2026
• Newsweek (2026, September 2) El Niño is Reshaping this Year’s Hurricane Season. Accessed September 3, 2026.
• NOAA (2026, June 2) How does El Niño Impact Atlantic Hurricane Season. Accessed September 3, 2026.
• NOAA (2026, May 21) NOAA 2026 Eastern Pacific Hurricane Season Outlook. Accessed September 3, 2026.
• Yale Climate Connections (2026, September 2) Edouard delivers an outsized flash-flood punch to eastern Texas. Accessed September 3, 2026.

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NASA awarded Blue Origin a contract Tuesday to develop the agency’s Mars Telecommunications Network, a next-generation communications system that will enable reliable, high-bandwidth communications and navigation services for current and future Mars missions.

The firm-fixed-price contract has a maximum potential value of approximately $700 million to deliver a high-performance Mars telecommunications orbiter to NASA no later than Dec. 31, 2028.

Blue Origin will design, develop, integrate, launch, and operate the network as a part of the agency’s broader space communications and navigation infrastructure. The architecture will consist of a high-performance telecommunications spacecraft orbiting Mars, transmitting science data, imagery, navigation information, and critical mission communications for spacecraft operating on and around the planet.

The award marks a milestone in NASA’s strategy to expand communications and navigation services beyond Earth and the Moon, establishing the foundation for sustained exploration of Mars in the coming decades.

Under the Artemis program, NASA is sending astronauts to explore the Moon and prepare for missions to Mars. Robotic missions will pave the way for human exploration of the Red Planet, and as these missions expand, demand for data will continue to increase. To meet this need, NASA is pursuing a purpose-built network capable of supporting a growing number of missions while providing greater capacity, reliability, and operational flexibility.

The selection follows NASA’s request for proposal issued in May. As the agency increasingly taps commercial partners for transportation and communications services in Earth orbit and to develop the Moon Base, the Mars Telecommunications Network initiative similarly seeks to harness private-sector capabilities while enabling NASA to focus on exploration and scientific discovery.

The network, managed by NASA’s Space Communications and Navigation program, is expected to be operational at Mars by 2030 and will support both current and future missions to the Red Planet, as NASA ventures deeper into space.

For more information about NASA’s space communications efforts, visit:

https://www.nasa.gov/communicating-with-missions

-end-

Rob Margetta
Headquarters, Washington
202-358-0918
[email protected]

Rob Garner
Goddard Space Flight Center, Greenbelt, Md.
301-286-5687
[email protected]

Source: www.nasa.gov

NASA’s Deep Space Network facility in California is marking the addition of a brand new 34-meter-wide (114-foot-wide) radio frequency antenna to the agency’s deep space communications and navigation system. The network uses giant dish antennas located at three global facilities to support more than 40 spacecraft exploring the solar system and interstellar space.

The new Deep Space Station 23 (DSS-23) is located at the Goldstone Deep Space Communications Complex, near Barstow, and is managed by NASA’s Jet Propulsion Laboratory in Southern California.

NASA leadership and personnel as well as dignitaries gathered at the complete DSS-23 antenna for a ceremonial ribbon cutting. It’s the latest to be added as part of the Deep Space Network’s Aperture Enhancement Project, which began in 2009 to upgrade and expand the network by adding six new 34-meter multifrequency beam-waveguide antennas. These versatile dishes can enhance many missions operating over different radio frequencies.

“By expanding the Deep Space Network, we are strengthening the communications foundation NASA needs for the bold missions ahead — from exploring more of the Moon than ever before to peering deeper into the solar system,” said James Kenyon, associate administrator of the Research and Technology Mission Directorate at NASA Headquarters in Washington. “This new antenna will help us deliver on our national goals for space exploration and push beyond the limits of what once seemed impossible.”

After completing a testing campaign from May through July to demonstrate its capabilities, the new DSS-23 began operations on Aug. 3, tracking NASA’s Chandra X-ray Observatory. Since then, it has been communicating with dozens of missions such as NASA’s Mars Reconnaissance Orbiter, Psyche, Juno, Voyager 1, and other robotic spacecraft in deep space.

“The addition of this next-generation antenna brings us closer to a completely modernized network that embraces advanced technology to ensure NASA’s leadership in deep space communications,” said Dave Gallagher, director of JPL. “After over 60 years of continuous operations supporting consequential missions, these upgrades prime the network for a new era of exploration. The teams that designed, planned, and built DSS-23 should be proud.”

Enhanced capabilities

Construction of DSS-23 began in February 2020. After the 133-ton metal reflector framework was placed and bolted atop the antenna’s pedestal in December 2024, engineers installed the panels to the framework that reflect radio frequency signals transmitted to and received from spacecraft. Then came the careful process of calibrating the antenna so it can work in concert with the rest of the network.

It is the fifth antenna at Goldstone (joining three 34-meter antennas and one 70-meter, or 230-foot, antenna) and the fifth enhancement project antenna to join the network, which includes antennas at the DSN’s Goldstone, Madrid, and Canberra, Australia, complexes. Multifrequency beam waveguide antennas direct signals down to a stable, climate-controlled underground room, rather than housing heavy, sensitive electronic equipment on the moving antenna dish. In addition to offering versatility, this design allows easy access for maintenance and upgrades to the system.

“The biggest challenge wasn’t actually constructing the antenna. It was transforming a complex collection of mechanical, electrical, software, radio frequency, and infrastructure systems into a single, mission-ready asset,” said Germaine Aziz, manager of the Deep Space Network Aperture Enhancement Project at JPL. “Every subsystem must be integrated, calibrated, and verified to operate with extraordinary precision and reliability before it can support NASA’s deep space missions.”

The enhancement project will be complete when a sixth enhancement-project antenna, Deep Space Station 33, comes online at the Canberra facility in 2029, bringing the total number of 34-meter antennas across the network to 13. The 34-meter antennas can be arrayed (combined and operated together) to provide an equivalent communications backup for each facility’s single 70-meter antenna, which, after more than 50 years of near-continuous operation, are getting increasingly costly to maintain and repair.

Managed by Caltech for NASA, JPL manages the agency’s Deep Space Network with the oversight of NASA’s SCaN (Space Communications and Navigation) Program within NASA’s Research and Technology Mission Directorate. More than 100 NASA and non-NASA missions rely on the Deep Space Network and Near Space Network. They include missions that support astronauts aboard the International Space Station and future Artemis missions, monitoring Earth, exploring the Moon, and exploring the solar system and beyond. 

For more information about the Deep Space Network, visit:

https://www.nasa.gov/communicating-with-missions/dsn

Source: www.nasa.gov

Copernicus, a generalized spacecraft trajectory design and optimization system, is capable of solving a wide range of trajectory problems such as planet or moon centered trajectories, libration point trajectories, planet-moon transfers and tours, and all types of interplanetary and asteroid/comet missions.

Latest News

• August 21, 2026: Copernicus Version 5.4.2 is now available. This is a bugfix release.
• May 26, 2026: Copernicus Version 5.4.1 is now available. This is a bugfix release with a few new features.
• March 23, 2026: Copernicus Version 5.4 is now available. This update includes numerous new features, enhancements, and bug fixes. This is also the first release with native support for Macs with Apple Silicon processors. Other updates include: New altitude and eclipse ramping/buffer engine model options; New propagation model to simulate a finite burn segment with a series of Kepler arcs & impulses; New circular restricted three-body problem (CR3BP) parameterization and propagation mode; New shadowing/eclipse model upgrades; New two-body rotating frame definition options; Many new GUI enhancements, usability upgrades, & improvements; Many enhancements and upgrades to the Copernicus Python API.
• August 13, 2024: Copernicus Version 5.3.2 is now available.
• December 18, 2023: Copernicus Version 5.3.1 is now available. This is a bugfix release.
• November 15, 2023: Copernicus Version 5.3 is now available. This update includes many bug fixes and various new features and refinements. Including: a new Copernicus mission file format, updates to kernels, a significant expansion of the beta Python API, and various new integration methods. In addition, we have upgraded to Python 3.10, and all dependencies are now obtained via conda.
• January 21, 2022: Copernicus Version 5.2 is now available. This update includes many bug fixes and various new features and refinements.
• June 17, 2021: Copernicus was selected as winner of the 2021 NASA Software of the Year Award.
• March 4, 2021: Copernicus Version 5.1 is now available. This update includes many bug fixes and various new features and refinements.
• June 26, 2020: Copernicus Version 5.0 is now available. This is a significant update to Copernicus and includes: A new modern Python-based GUI that is now cross-platform and fully functional on Windows, Linux, and macOS, 3D graphics upgrades including antialiasing and celestial body shadowing, a new Python scripting interface, many other new features and options, and bug fixes.
• May 1, 2018: Copernicus Version 4.6 is now available. The release includes the following changes: a new cross-platform JSON kernel file format, various new reference frame features, including new capabilities for user-defined reference frame plugins, and numerous bug fixes and other minor enhancements.
• January 24, 2018: Copernicus Version 4.5 is now available. The new version includes a new experimental Mac version, faster exporting of segment data output files (including the addition of a new binary HDF5 format), some new GUI tools, new plugin capabilities, and numerous other new features and bug fixes.
• October 1, 2016: Copernicus Version 4.4 is now available. The new version includes 3D graphics improvements and various other new features and bug fixes.
• February 8, 2016: Copernicus Version 4.3 is now available. The new version includes updates to the plugin interface, a new differential corrector solution method, updated SPICE SPK files, updates to the Python interface, new training videos, as well as numerous other refinements and bug fixes.
• July 21, 2015: Copernicus Version 4.2 is now available.  The update includes further refinements to the new plugin feature, as well as various other new features and some bug fixes.
• April 13, 2015: Copernicus Version 4.1 is now available.  This update includes a new plugin architecture to enable extending Copernicus with user-created algorithms.  It also includes a new Python interface, as well as various other new features and bug fixes.
• August 13, 2014: Copernicus Version 4.0 is now available.  This is an update to version 3.1, which was released in June 2012.  The new release includes many new features, bug fixes, performance and stability improvements, as well as a redesigned GUI, a new user guide, and full compatibility with Windows 7.  The update is recommended for all Copernicus users.

Development

The Copernicus Project started at the University of Texas at Austin in August 2001. In June 2002, a grant from the NASA Johnson Space Center (JSC) was used to develop the first prototype which was completed in August 2004. In the interim, support was also received from NASA’s In Space Propulsion Program and from the Flight Dynamics Vehicle Branch of Goddard Spaceflight Center. The first operational version was completed in March 2006 (v1.0). The initial development team consisted of Dr. Cesar Ocampo and graduate students at the University of Texas at Austin Department of Aerospace Engineering and Engineering Mechanics. Since March 2007, primary development of Copernicus has been at the Flight Mechanics and Trajectory Design Branch of JSC.

Request Copernicus

The National Aeronautics and Space Act of 1958 and a series of subsequent legislation recognized transfer of federally owned or originated technology to be a national priority and the mission of each Federal agency. The legislation specifically mandates that each Federal agency have a formal technology transfer program, and take an active role in transferring technology to the private sector and state and local governments for the purposes of commercial and other application of the technology for the national benefit. In accordance with NASA’s obligations under mandating legislation, JSC makes Copernicus available free of charge to other NASA centers, government contractors, and universities, under the terms of a US government purpose license.  Organizations interested in obtaining Copernicus should click here to request it.

Current Version

The current version of Copernicus is 5.4.1 (released May 26, 2026).

References

Publications about Copernicus

• C. A. Ocampo, “An Architecture for a Generalized Trajectory Design and Optimization System”, Proceedings of the International Conference on Libration Points and Missions, June, 2002.
• C. A. Ocampo, “Finite Burn Maneuver Modeling for a Generalized Spacecraft Trajectory Design and Optimization System”, Annals of the New York Academy of Science, May 2004.
• C. A. Ocampo, J. Senent, “The Design and Development of Copernicus: A Comprehensive Trajectory Design and Optimization System”, Proceedings of the International Astronautical Congress, 2006. IAC-06-C1.4.04.
• R. Mathur, C. A. Ocampo, “An Architecture for Incorporating Interactive Visualizations into Scientific Simulations”, Advances in the Astronautical Sciences, Feb. 2007.
• C. A. Ocampo, J. S. Senent, J. Williams, “Theoretical Foundation of Copernicus: A Unified System for Trajectory Design and Optimization”, 4th International Conference on Astrodynamics Tools and Techniques, May 2010.
• J. Williams, J. S. Senent, C. A. Ocampo, R. Mathur, “Overview and Software Architecture of the Copernicus Trajectory Design and Optimization System”, 4th International Conference on Astrodynamics Tools and Techniques, May 2010.
• J. Williams, J. S. Senent, D. E. Lee, “Recent Improvements to the Copernicus Trajectory Design and Optimization System”, Advances in the Astronautical Sciences, 2012.
• J. Williams, “A New Architecture for Extending the Capabilities of the Copernicus Trajectory Optimization Program”, Advances in the Astronautical Sciences, 2015, volume 156.
• J. Williams, R. D. Falck, and I. B. Beekman. “Application of Modern Fortran to Spacecraft Trajectory Design and Optimization“, 2018 Space Flight Mechanics Meeting, AIAA SciTech Forum, (AIAA 2018-1451)
• J. Williams, A. H. Kamath, R. A. Eckman, G. L. Condon, R. Mathur, and D. Davis, “Copernicus 5.0: Latest Advances in JSC’s Spacecraft Trajectory Optimization and Design System”, 2019 AAS/AIAA Astrodynamics Specialist Conference, Portland, ME, August 11-15, 2019, AAS 19-719
• J. Williams, J. S. Senent, R. Mathur, and S. M. Stewart, “A History of Copernicus: The Origin, Development, and Evolution of JSC’s Spacecraft Trajectory Design and Optimization System”, AAS/AIAA Astrodynamics Specialist Conference, Boston, MA, August 2025, AAS 25-576.

Some studies that have used Copernicus

• C. L. Ranieri, C. A. Ocampo, “Optimization of Roundtrip, Time-Constrained, Finite Burn Trajectories via an Indirect Method”, Journal of Guidance, Control, and Dynamics, Vol. 28, No. 2, March-April 2005.
• T. Polsgrove, L. Kos, R. Hopkins, T. Crane, “Comparison of Performance Predictions for New Low-Thrust Trajectory Tools”, AIAA/AAS Astrodynamics Specialist Conference, August, 2006.
• L. D. Kos, T. P. Polsgrove, R. C. Hopkins, D. Thomas and J. A. Sims, “Overview of the Development for a Suite of Low-Thrust Trajectory Analysis Tools”, AIAA/AAS Astrodynamics Specialist Conference, August, 2006.
• M. Garn, M. Qu, J. Chrone, P. Su, C. Karlgaard, “NASA’s Planned Return to the Moon: Global Access and Anytime Return Requirement Implications on the Lunar Orbit Insertion Burns”, AIAA/AAS Astrodynamics Specialist Conference and Exhibit, August, 2008.
• R. B. Adams, “Near Earth Object (NEO) Mitigation Options Using Exploration Technologies”, Asteroid Deflection Research Symposium, Oct. 2008.
• J. Gaebler, R. Lugo, E. Axdahl, P. Chai, M. Grimes, M. Long, R. Rowland, A. Wilhite, “Reusable Lunar Transportation Architecture Utilizing Orbital Propellant Depots”, AIAA SPACE 2009 Conference and Exposition, September 2009.
• J. Williams, E. C. Davis, D. E. Lee, G. L. Condon, T. F. Dawn, “Global Performance Characterization of the Three Burn Trans-Earth Injection Maneuver Sequence over the Lunar Nodal Cycle”, Advances in the Astronautical Sciences, Vol. 135, 2010. AAS 09-380
• J. Williams, S. M. Stewart, D. E. Lee, E. C. Davis, G. L. Condon, T. F. Dawn, J. Senent, “The Mission Assessment Post Processor (MAPP): A New Tool for Performance Evaluation of Human Lunar Missions”, 20th AAS/AIAA Space Flight Mechanics Meeting, Feb. 2010.
• J. W. Dankanich, L. M. Burke, J. A. Hemminger, “Mars sample return Orbiter/Earth Return Vehicle technology needs and mission risk assessment”, 2010 IEEE Aerospace Conference, March 2010.
• A. V. Ilin, L. D. Cassady, T. W. Glover, M. D. Carter, F. R. Chang Diaz, “A Survey of Missions using VASIMR for Flexible Space Exploration”, Ad Astra Rocket Company, Document Number JSC-65825, April 2010.
• J. W. Dankanich, B. Vondra, A. V. Ilin, “Fast Transits to Mars Using Electric Propulsion”, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 2010.
• S. R. Oleson, M. L. McGuire, L. Burke, J. Fincannon, T. Colozza, J. Fittje, M. Martini, T. Packard, J. Hemminger, J. Gyekenyesi, “Mars Earth Return Vehicle (MERV) Propulsion Options”, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 2010, AIAA 2010-6795.
• J. S. Senent, “Fast Calculation of Abort Return Trajectories for Manned Missions to the Moon”, AIAA/AAS Astrodynamics Specialist Conference, August 2010.
• D. S. Cooley, K. F. Galal, K. Berry, L. Janes, G. Marr. J. Carrico. C. Ocampo, “Mission Design for the Lunar CRater Observation and Sensing Satellite (LCROSS)”, AIAA/AAS Astrodynamics Specialist Conference, August, 2010.
• A. V. Ilin, L. D. Cassady, T. W. Glover, F. R. Chang Diaz, “VASIMR Human Mission to Mars”, Space, Propulsion & Energy Sciences International Forum, March 15-17, 2011.
• J. Brophy, F. Culick, L. Friedman, et al., “Asteroid Retrieval Feasibility Study,” Technical Report, Keck Institute for Space Studies, California Institute of Technology, Jet Propulsion Laboratory, April 2012.
• A. V. Ilin, “Low Thrust Trajectory Analysis (A Survey of Missions using VASIMR for Flexible Space Exploration – Part 2), Ad Astra Rocket Company, Document Number JSC-66428, June 2012.
• P. R. Chai, A. W. Wilhite, “Station Keeping for Earth-Moon Lagrangian Point Exploration Architectural Assets”, AIAA SPACE 2012 Conference & Exposition, September, 2012, AIAA 2012-5112.
• F. R. Chang Diaz, M. D. Carter, T. W. Glover, A. V. Ilin, C. S. Olsen, J. P. Squire, R. J. Litchford, N. Harada, S. L. Koontz, “Fast and Robust Human Missions to Mars with Advanced Nuclear Electric Power and VASIMR Propulsion”, Proceedings of Nuclear and Emerging Technologies for Space, Feb. 2013. Paper 6777.
• J. Williams, “Trajectory Design for the Asteroid Redirect Crewed Mission”, JSC Engineering, Technology and Science (JETS) Contract Technical Brief JETS-JE23-13-AFGNC-DOC-0014, July, 2013.
• J.P. Gutkowski, T.F. Dawn, R.M. Jedrey, “Trajectory Design Analysis over the Lunar Nodal Cycle for the Multi-Purpose Crew Vehicle (MPCV) Exploration Mission 2 (EM-2)”, Advances in the Astronautical Sciences Guidance, Navigation and Control, Vol. 151, 2014. AAS 14-096.
• R. G. Merrill, M. Qu, M. A. Vavrina, C. A. Jones, J. Englander, “Interplanetary Trajectory Design for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study”, AIAA/AAS Astrodynamics Specialist Conference, 2014. AIAA 2014-4457.
• J. Williams, G. L. Condon. “Contingency Trajectory Planning for the Asteroid Redirect Crewed Mission”, SpaceOps 2014 Conference (AIAA 2014-1697).
• J. Williams, D. E. Lee, R. J. Whitley, K. A. Bokelmann, D. C. Davis, and C. F. Berry. “Targeting cislunar near rectilinear halo orbits for human space exploration“, AAS 17-267
• T. F. Dawn, J. Gutkowski, A. Batcha, J. Williams, and S. Pedrotty. “Trajectory Design Considerations for Exploration Mission 1“, 2018 Space Flight Mechanics Meeting, AIAA SciTech Forum, (AIAA 2018-0968)
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Source: www.nasa.gov