Engineering topics

Kennedy, John J.

Publications and source records attributed to Kennedy, John J..

4 records

NASA NTRS2018

Balancing Public & Private Partnerships for Future Human Spaceflight

Privatization is key to America's current and future interests in Space and is consistent with the 2010 Title 51 "National Aeronautics and Space Act" which states "COMMERCIAL USE OF SPACE. - Congress declares that the general welfare of the United States requires that the Administration seek and encourage, to the maximum extent possible, the fullest commercial use of space." With this thought in mind, this paper discusses several key considerations when entering into a Human Spaceflight Public/Private partnership, with particular attention to the engineering team engagement. NASA's historically develops technology and capability in areas that are not commercially profitable but can enable future commercial opportunities. By leveraging the experiences and lessons learned from the past, we can improve our opportunities for success in the future. We have made great strides in these areas, but there is significant room for improvement. This paper intends to highlight many of the thoughts and considerations, which are necessary when developing a public/private partnership for "Human Spaceflight". Although this paper is being developed with an emphasis on "Human Spaceflight", many of the thoughts may have applicability to un-crewed missions. This paper does not attempt to define specific lines between government and private entities, since those lines vary based on many factors such as allocation of roles, responsibilities and accountabilities between participants and risk tolerance for both safety of flight and mission success.

Kennedy, John J.↗

DOE OSTI2013

Global analysis of night marine air temperature and its uncertainty since 1880

An updated version of the Met Office Hadley Centre's monthly night marine air temperature data set is presented. It is available on a 5° latitude-longitude grid from 1880 as anomalies relative to 1961–1990 calendar-monthly climatological average night marine air temperature (NMAT). Adjustments are made for changes in observation height; these depend on estimates of the stability of the near surface atmospheric boundary layer. In previous versions of the data set, ad hoc adjustments were also made for three periods and regions where poor observational practice was prevalent. These adjustments are re-examined. Estimates of uncertainty are calculated for every grid box and result from measurement errors, uncertainty in adjustments applied to the observations, uncertainty in the measurement height, and under-sampling. The new data set is a clear improvement over previous versions in terms of coverage because of the recent digitization of historical observations from ships' logbooks. However, the periods prior to about 1890 and around World War II remain particularly uncertain, and sampling is still sparse in some regions in other periods. A further improvement is the availability of uncertainty estimates for every grid box and every month. Previous versions required adjustments that were dependent on contemporary measurements of sea surface temperature (SST); to avoid these, the new data set starts in 1880 rather than 1856. Overall agreement with variations of SST is better for the updated data set than for previous versions, supporting existing estimates of global warming and increasing confidence in the global record of temperature variability and change.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2012

Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 data set

Recent developments in observational near-surface air temperature and sea-surface temperature analyses are combined to produce HadCRUT4, a new data set of global and regional temperature evolution from 1850 to the present. This includes the addition of newly digitized measurement data, both over land and sea, new sea-surface temperature bias adjustments and a more comprehensive error model for describing uncertainties in sea-surface temperature measurements. An ensemble approach has been adopted to better describe complex temporal and spatial interdependencies of measurement and bias uncertainties and to allow these correlated uncertainties to be taken into account in studies that are based upon HadCRUT4. Climate diagnostics computed from the gridded data set broadly agree with those of other global near-surface temperature analyses. Fitted linear trends in temperature anomalies are approximately 0.07°C/decade from 1901 to 2010 and 0.17°C/decade from 1979 to 2010 globally. Northern/southern hemispheric trends are 0.08/0.07°C/decade over 1901 to 2010 and 0.24/0.10°C/decade over 1979 to 2010. Linear trends in other prominent near-surface temperature analyses agree well with the range of trends computed from the HadCRUT4 ensemble members.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1987

The preloadable vector sensitive latch for orbital docking/berthing

The workings and function of the Preloader Vector Sensitive Latch are described. A discussion of docking systems used in the U.S. manned space flight programs is included to show how docking systems have evolved, and to highlight the potential advantages of a preloadable vector sensitive latch in such systems.

Acres, William R.↗