Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “clifford”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2

STS-76 Flight Day 3

On this third day of the STS-76 mission, the flight crew, Cmdr Kevin P. Chilton, Pilot Richard A. Searfoss, and Mission Specialists Shannon W. Lucid, Linda M. Godwin, and Ronald M. Sega, are shown performing the docking maneuvers for the Mir Space Station and the Atlantis in-orbit rendezvous. The Atlantis crew is shown greeting the Mir cosmonaut crew, Cmdr. Yuri Onufrienko and Flight Engineer Yuri Usachev. The docking procedure is shown from both outside and inside the Atlantis. An interview with Mission Control is shown from inside Mir with both crews present. There is footage of the Mir, both docked with Atlantis and free flying. Not shown is the EVA by Clifford and Godwin to attach several experimental packages to the exterior of the Mir docking module, although their packing preparation is shown.

Source record↗

STS-76 Flight Day 5

On this fifth day of the STS-76 mission, the flight crew, Cmdr. Kevin P. Chilton, Pilot Richard A. Searfoss, and Mission Specialists Shannon W. Lucid, Linda M. Godwin, Michael R. Clifford, and Ronald M. Sega, pay tribute to the late astronaut Bob Overmeyer with views from the Atlantis/Mir configuration with the Earth in the background. Atlantis astronauts, interviewed by reporters from NASA Centers and Russia during an in-orbit press conference, describe their observations of Comet Hyakutake as it continues its close pass by Earth, remarking on the comet's brilliance and visibility. The astronauts and cosmonauts also took time out from their transfer and resupply activities to talk with Charlie Gibson of 'Good Morning America'.

Source record↗

STS-76 Flight Day 4

On this fourth day of the STS-76 mission, the flight crew, Cmdr. Kevin P. Chilton, Pilot Richard A. Searfoss, and Mission Specialists Shannon W. Lucid, Linda M. Godwin, Michael R. Clifford, and Ronald M. Sega, are shown performing various experiments on the Middeck and transferring supplies to the Mir Space Station. Godwin explains the European Space Agency (ESA) Biorack investigations. Chilton, Lucid and Mir Cmdr. Yuri Onufrienko talk with NASA Administrator Dan Goldin via satellite link. Lucid will be joining the cosmonauts, Onufrienko and Flight Engineer Yuri Usachev, for a 140-day mission on Mir.

Source record↗

Walking to Olympus: An EVA Chronology

Spacewalkers enjoy a view of Earth once reserved for Apollo, Zeus, and other denizens of Mt. Olympus. During humanity's first extravehicular activity (EVA), Alexei Leonov floated above Gibraltar, the rock ancient seafarers saw as the gateway to the great unknown Atlantic. The symbolism was clear, Leonov stepped past a new Gibraltar when he stepped into space. More than 32 years and 154 EVAs later, Jerry Linenger conducted an EVA with Vladimir Tsibliyev as part of International Space Station Phase 1. They floated together above Gibraltar. Today the symbolism has new meaning: humanity is starting to think of stepping out of Earth orbit, space travel's new Gibraltar, and perhaps obtaining a new olympian view, a close-up look at Olympus Mons on Mars. Walking to Olympus: An EVA Chronology chronicles the 154 EVAs conducted from March 1965 to April 1997. It is intended to make clear the crucial role played by EVA in the history of spaceflight, as well as to chronicle the large body of EVA "lessons learned." Russia and the U.S. define EVA differently. Russian cosmonauts are said to perform EVA any time they are in vacuum in a space suit. A U.S. astronaut must have at least his head outside his spacecraft before he is said to perform an EVA. The difference is based in differing spacecraft design philoso- phies. Russian and Soviet spacecraft have always had a specialized airlock through which the EVA cosmonaut egressed, leaving the main habitable volume of the spacecraft pressurized. The U.S. Gemini and Apollo vehicles, on the other hand, depressurized their entire habitable volume for egress. In this document, we apply the Russian definition to Russian EVAS, and the U.S. definition to U.S. EVAS. Thus, for example, Gemini 4 Command Pilot James McDivitt does not share the honor of being first American spacewalker with Ed White, even though he was suited and in vacuum when White stepped out into space. Non-EVA spaceflights are listed in the chronology to provide context and to display the large num- ber of flights in which EVA played a role. This approach also makes apparent significant EVA gaps, for example, the U.S. gap between 1985 and 1991 following the Challenger accident. This NASA History Monograph is an edited extract from an extensive EVA Chronology and Reference Book being produced by the EVA Project Office, NASA Johnson Space Center, Houston, Texas. The larger work will be published as part of the NASA Formal Series in 1998. The authors gratefully acknowledge the assistance rendered by Max Ary, Ashot Bakunts, Gert-Jan Bartelds, Frank Cepollina, Andrew Chaikin, Phillip Clark, Richard Fullerton, Steven Glenn, Linda Godwin, Jennifer Green, Greg Harris, Clifford Hess, Jeffrey Hoffman, David Homan, Steven Hopkins, Nicholas Johnson, Eric Jones, Neville Kidger, Joseph Kosmo, Alexei Lebedev, Mark Lee, James LeBlanc, Dmitri Leshchenskii, Jerry Linenger, Igor Lissov, James McBarron, Clay McCullough, Joseph McMann, Story Musgrave, Dennis Newkirk, James Oberg, Joel Powell, Lee Saegesser, Andy Salmon, Glen Swanson, Joseph Tatarewicz, Kathy Thornton, Chris Vandenberg, Charles Vick, Bert Vis, David Woods, Mike Wright, John Young, and Keith Zimmerman. Special thanks to Laurie Buchanan, John Charles, Janet Kovacevich, Joseph Loftus, Sue McDonald, Martha Munies, Colleen Rapp, and Jerry Ross. Any errors remain the responsibility of the authors.

Portree, David S. F.↗

Third Annual HEDS-UP Forum

The HEDS-UP (Human Exploration and Development of Space-University Partners) program has been instituted to build new relationships between university faculty and students and NASA in support of the Human Exploration and Development of Space. The program provides a mechanism whereby university students can explore problems of interest to NASA through student design projects, led by a university professor or mentor, and aided by the HEDSUP staff. HEDS-UP advises on the type of project that is of interest and provides contacts to NASA and industry professionals who may serve as mentors to the student project. Students become acquainted with objectives, strategies, development issues, and technologic characteristics of space exploration programs. In doing so, they are preparing themselves for future engineering challenges and may well find that the program is on their critical path to professional advancement. Many of the ideas are novel and are of interest to NASA. Industry finds in HEDS-UP a mechanism to meet many bright and enthusiastic students who are about to enter the work force. The universities become more involved with space exploration and the students are encouraged to include an outreach element in their work, to bring their efforts and their excitement to others in their universities or in their communities. The climax of the HEDS-UP program each year is the HEDS-UP Forum, held at the Lunar and Planetary Institute. Here, the university teams bring their projects - written reports, oral reports, models, prototypes, and experiment demonstrations - to show to one another and to NASA and industry participants. NASA, industry, and academic professionals present discussions of problems of current interest to space exploration. All meet informally around the posters that each of the teams brings to the Forum. This year the HEDS-UP Forum was held May 4-5 at the Lunar and Planetary Institute in Houston. Thirteen university teams from twelve universities participated. Eleven teams were undergraduate teams; two were composed of graduate students. Each team contributed a 20-page written report, and these reports are reproduced in this volume. The specially invited NASA presenters included Mr. John Connolly, Dr. David McKay and Dr. Donald Henninger of the NASA Johnson Space Center, Dr. Paul Spudis and Dr. Steve Clifford of the Lunar and Planetary Institute, and Dr. Pascal Lee of the NASA Ames Research Center.

Duke, Michael B.↗

STS-53 TCDT Training and Press Q&A at Pad A

Footage shows the training activities for the crew of STS-53 (Commander David M. Walker, Pilot Robert D. Cabana, and Mission Specialists Guion S. Bluford, James S. Voss, and Michael R. Clifford), including Emergency Egress Training. Commander Walker introduces the crew and they answer questions from the press.

Source record↗

STS-53 TCDT O&C Exit

Footage shows the crew of STS-53 (Commander David M. Walker, Pilot Robert D. Cabana, and Mission Specialists Guion S. Bluford, James S. Voss, and Michael R. Clifford) leaving the Operations and Checkout (O&C) Building during the Terminal Countdown and Demonstration Test (TCDT).

Source record↗

STS-53 TCDT Activities

The crew of STS-53, Commander David M. Walker, Pilot Robert D. Cabana, and Mission Specialists Guion S. Bluford, James S. Voss, and Michael R. Clifford, is seen during Terminal Countdown Demonstration Test (TCDT) activities. Included is footage of Emergency Egress Training and a press question and answer session.

Source record↗

STS-59 Crew Arrival

The crew of STS-59, Commander Sidney M. Gutierrez, Pilot Kevin P. Chilton, Payload Commander Linda M. Godwin, and Mission Specialists Jay Apt, Michael R. Clifford, and Thomas D. Jones, emerge from several T-38 aircraft. Commander Gutierrez introduces the crew and they each make a brief statement about the upcoming Endeavour mission.

Source record↗

Evaluating Putative Shoreline Adjacent to the Dichotomy Boundary near Arabia Terra

In 1989, Parker et al. identified two geologic contacts, Contact #1 and Contact #2, which they believed demarcated two distinct highstands of a global ocean ponded within the northern lowlands. Since then, Clifford and Parker presented new nomenclature for Contact #1 and Contact #2, now known as the Arabia and Deuteronilus trends, respectively. To date, a total of nine putative shorelines have been identified by Parker et al., who categorized both global and regional scale trends. Our approx. 400,000 sq km study area is just north of Arabia Terra, contiguous to the dichotomy boundary and centered on Cydonia Mensae. It is significant in further testing the shoreline hypothesis because it contains both the global scale trends Arabia and Deuteronilus, along with a regional trend known as Acidalia.

Valeri E Webb↗

A Radiation Chemistry Code Based on the Greens Functions of the Diffusion Equation

Ionizing radiation produces several radiolytic species such as.OH, e-aq, and H. when interacting with biological matter. Following their creation, radiolytic species diffuse and chemically react with biological molecules such as DNA. Despite years of research, many questions on the DNA damage by ionizing radiation remains, notably on the indirect effect, i.e. the damage resulting from the reactions of the radiolytic species with DNA. To simulate DNA damage by ionizing radiation, we are developing a step-by-step radiation chemistry code that is based on the Green's functions of the diffusion equation (GFDE), which is able to follow the trajectories of all particles and their reactions with time. In the recent years, simulations based on the GFDE have been used extensively in biochemistry, notably to simulate biochemical networks in time and space and are often used as the "gold standard" to validate diffusion-reaction theories. The exact GFDE for partially diffusion-controlled reactions is difficult to use because of its complex form. Therefore, the radial Green's function, which is much simpler, is often used. Hence, much effort has been devoted to the sampling of the radial Green's functions, for which we have developed a sampling algorithm This algorithm only yields the inter-particle distance vector length after a time step; the sampling of the deviation angle of the inter-particle vector is not taken into consideration. In this work, we show that the radial distribution is predicted by the exact radial Green's function. We also use a technique developed by Clifford et al. to generate the inter-particle vector deviation angles, knowing the inter-particle vector length before and after a time step. The results are compared with those predicted by the exact GFDE and by the analytical angular functions for free diffusion. This first step in the creation of the radiation chemistry code should help the understanding of the contribution of the indirect effect in the formation of DNA damage and double-strand breaks.

Plante, Ianik↗

Electrolysis cell functions as water vapor dehumidifier and oxygen generator

Water vapor is absorbed in hygroscopic electrolyte, and oxygen generated by absorbed water electrolysis at anode is added simultaneously to air stream. Cell applications include on-board aircraft oxygen systems, portable oxygen generators, oxygen concentration requirements, and commercial air conditioning and dehumidifying systems.

Clifford, J. E.↗