Engineering topics

Lester, Dan

Publications and source records attributed to Lester, Dan.

8 records

NASA NTRS2013

Future In-Space Operations (FISO): A Working Group and Community Engagement

Long-duration human capabilities beyond low Earth orbit (LEO), either in support of or as an alternative to lunar surface operations, have been assessed at least since the late 1960s. Over the next few months, we will present short histories of concepts for long-duration, free-space human habitation beyond LEO from the end of the Apollo program to the Decadal Planning Team (DPT)/NASA Exploration Team (NExT), which was active in 1999 2000 (see Forging a vision: NASA s Decadal Planning Team and the origins of the Vision for Space Exploration , The Space Review, December 19, 2005). Here we summarize the brief existence of the Future In-Space Operations (FISO) working group in 2005 2006 and its successor, a telecon-based colloquium series, which we co-moderate.

Thronson, Harley↗

NASA NTRS2011

Human Space Exploration and Human Space Flight: Latency and the Cognitive Scale of the Universe

The role of telerobotics in space exploration as placing human cognition on other worlds is limited almost entirely by the speed of light, and the consequent communications latency that results from large distances. This latency is the time delay between the human brain at one end, and the telerobotic effector and sensor at the other end. While telerobotics and virtual presence is a technology that is rapidly becoming more sophisticated, with strong commercial interest on the Earth, this time delay, along with the neurological timescale of a human being, quantitatively defines the cognitive horizon for any locale in space. That is, how distant can an operator be from a robot and not be significantly impacted by latency? We explore that cognitive timescale of the universe, and consider the implications for telerobotics, human space flight, and participation by larger numbers of people in space exploration. We conclude that, with advanced telepresence, sophisticated robots could be operated with high cognition throughout a lunar hemisphere by astronauts within a station at an Earth-Moon Ll or L2 venue. Likewise, complex telerobotic servicing of satellites in geosynchronous orbit can be carried out from suitable terrestrial stations.

Lester, Dan↗

NASA NTRS2011

The Space Review

Human space flight in the US and other space-faring countries is faced with a twin challenge that is likely to persist for many years: flat or declining budgets along with an expectation of continuing, significant achievements. A partial solution may involve increased participation by multiple commercial competitors with the promise - albeit yet to be fully demonstrated - of much-reduced costs. That said, most commercial goals are concentrated on low-Earth orbit (LEO) for the time being, leaving human trips beyond Earth orbit (BED) as governmental initiatives. The past decade, beginning with the 1999/2000 Decadal Planning Team (DPT)/NASA Exploration Team (NExT) human space flight studies for the White House Office of Management and Budget (http://history.nasa.gov/DPT/DPT.htm), can arguably be described as a Golden Age of engineering design, strategic planning, technology capability prioritization, and development programs on the International Space Station (ISS). However, cynics have criticized the same period as little more than PowerPoint presentations, and unfocused technology investments with only limited progress toward a goal of human space flight beyond the immediate vicinity of the Earth. We disagree with the cynics. Experience with the ISS on increasingly sophisticated capabilities have prepared international partners to deploy a major "stepping stone" for human space flight: a habitation system in free space beyond low-Earth orbit. Such an achievement would be a major milestone in human space flight and, very likely, an essential demonstration site for subsequent, very ambitious exploration missions such as to Mars. Developing critical capabilities for human voyages beyond LEO, such as Earth-Moon libration points, offers, as just one example, easy return to Earth within days (see, e.g., Farquhar 1971 (Aeronautics & Astronautics, July, p. 59ff), Thronson, Lester, and Talay 2011 (http://www.thespacereview.com/article/1756/1), and Lester 2012 (http://www.thespacereview.com/article/1650/1). Use of Earth-Moon libration points as sites for early demonstrations of capabilities necessary for human missions to Mars, for example, contrasts sharply with using missions to near-Earth asteroids (NEAs) for that purpose.

Thronson, Harley↗

NASA NTRS2010

Human Operations Beyond LEO by the End of the Decade: An Affordable Near-Term "Stepping Stone"

For more than a decade, several teams have assessed designs for a long-duration free-space human habitat beyond low-Earth orbit (LEO), building upon years of hard-won experience with the International Space Station (ISS). These systems would enable multiple achievements for science and human space flight. Most were intended to be deployed using available or near-future capabilities within about a decade after funding begins and serve as the first major human "stepping stone" beyond LEO. Last year, Thronson and Talay summarized work up to that time on expandable or inflatable concepts for deployment at an Earth-Moon (E-M) L1 or L2 location. Here we summarize our team's more recent work both on a long-duration human habitat that could be deployed beyond LEO within a decade and on the priority goals that such a habitat might accomplish. Particulars of this and other concepts for human operations in cis-lunar space are posted on the web and will be presented at professional conferences, and detailed in future publications by our group.

Thronson, Harley↗

NASA NTRS2006

Science Promise and Conceptual Mission Design for SAFIR - the Single Aperture Far Infrared Observatory

We report on completion of the SAFIR Vision Mission study, as organized by the NASA Science Mission Directorate. This study resulted in a focused baseline design for this large aperture space observatory that capitalizes on architectures being actively developed for JWST and other missions. Special opportunities for achieving thermal performance of this <10K telescope are reviewed, as well as efforts to understand capabilities and needs for focal plane instrument and I&T on this large (10m-class) telescope.

telescopes↗

NASA NTRS1999

A High Spatial Resolution Study of Far IR Emission of Galaxies

This grant funded observations and data reduction on the Kuiper Airborne Observatory. The research project was successfully completed. New insights into the distribution of far infrared emission across star-forming galaxies was obtained, and student training was achieved. The efforts contributed towards new observing strategies that will impact future NASA missions. The results of the effort have been presented in several papers in the refereed literature, including: "Morphology of Far Infrared Emission in Galaxies". "Far Infrared Thermal Emission from the Inner Cooling Flow Region of NGC1275". "Distribution of Light in the'Dusty-Hand'Galaxy NGC2146". Presentations of the results of this program have also been given at the following meetings and symposia: "High Spatial Resolution Study of the Active Cooling Flow Galaxy NGC 1275" "The Extent of Far IR Emission in Luminous Galaxies".

Lester, Dan↗

NASA NTRS1997

Science in the Stratosphere

The Science in the Stratosphere program, first established in 1992, was conceived to introduce K-6 teachers to airborne infrared astronomy through the Kuiper Airborne Observatory (KAO), and to use this venue as a basis for seeing scientists at work in a mission-intensive program. The teachers selected for this program would bring their new perspectives back to their schools and students. Unlike the related FOSTER program, the emphasis of this program was on more intensive exposure of the KAO mission to a small number of teachers. The teachers in the Science in the Stratosphere program essentially lived with the project scientists and staff for almost a week. One related goal was to imbed the KAO project with perspectives of working teachers, thereby sensitizing the project staff and scientists to educational outreach efforts in general, which is an important goal of the NASA airborne astronomy program. A second related goal was to explore the ways in which K-5 educators could participate in airborne astronomy missions. Also unlike FOSTER, the Science in the Stratosphere program was intentionally relatively unstructured, in that the teacher participants were wholly embraced by the science team, and were encouraged to 'sniff out' the flavor of the whole facility by talking with people.

Lester, Dan↗

NASA NTRS1988

Infrared astronomy from the Moon

The Moon offers some remarkable opportunities for performing infrared astronomy. Although the transportation overhead can be expected to be very large compared with that for facilities in Earth orbit, certain aspects of the lunar environment should allow significant simplifications in the design of telescopes with background limited performance, at least in some parts of the thermal infrared spectrum. Why leave the Earth to perform infrared astronomy is addressed as is the reasons for going all the way to the Moon for its environment.

Lester, Dan↗