NASA Scientific and Technical Aerospace Reports

20040074322 NASA Langley Research Center, Hampton, VA, USA
Parametric Studies of Square Solar Sails Using Finite Element Analysis
Sleight, David W.; Muheim, Danniella M.; March 25, 2004; 13 pp.; In English; 45th AIAA/ASME/ASCE/AHS/ASC
Structures, Structural Dynamics, and Materials Conference, 19-22 Apr. 2004, Palm Springs, CA, USA
Contract(s)/Grant(s): 755-06-00
Report No.(s): AIAA Paper 2004-1509; No Copyright; Avail: CASI; A03, Hardcopy
Parametric studies are performed on two generic square solar sail designs to identify parameters of interest. The studies
are performed on systems-level models of full-scale solar sails, and include geometric nonlinearity and inertia relief, and use
a Newton-Raphson scheme to apply sail pre-tensioning and solar pressure. Computational strategies and difficulties
encountered during the analyses are also addressed. The purpose of this paper is not to compare the benefits of one sail design
over the other. Instead, the results of the parametric studies may be used to identify general response trends, and areas of
potential nonlinear structural interactions for future studies. The effects of sail size, sail membrane pre-stress, sail membrane
thickness, and boom stiffness on the sail membrane and boom deformations, boom loads, and vibration frequencies are
studied. Over the range of parameters studied, the maximum sail deflection and boom deformations are a nonlinear function
of the sail properties. In general, the vibration frequencies and modes are closely spaced. For some vibration mode shapes,
local deformation patterns that dominate the response are identified. These localized patterns are attributed to the presence of
negative stresses in the sail membrane that are artifacts of the assumption of ignoring the effects of wrinkling in the modeling
process, and are not believed to be physically meaningful. Over the range of parameters studied, several regions of potential
nonlinear modal interaction are identified.
Author
Solar Sails; Stresses; Vibration Mode; Design Analysis; Dynamic Structural Analysis; Membrane Structures; Computation
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SPACECRAFT INSTRUMENTATION AND ASTRIONICS
Includes the design, manufacture, or use of devices for the purpose of measuring, detecting, controlling, computing, recording, or
processing data related to the operation of space vehicles or platforms. For related information see also 06 Avionics and Aircraft
Instrumentation; for spaceborne instruments not integral to the vehicle itself see 35 Instrumentation and Photography; for spaceborne
telescopes and other astronomical instruments see 89 Astronomy.
20040068196 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, USA
NASA Space Cryocooler Programs: A 2003 Overview
Ross, R. G., Jr.; Boyle, R. F.; Kittel, P.; International Thermal Detectors Workshop (TDW 2003); February 2004, pp. 6-1 -
6-7; In English; See also 20040068186; No Copyright; Avail: CASI; A02, Hardcopy
Mechanical cryocoolers represent a significant enabling technology for NASA’s Earth and Space Science missions. An
overview is presented of ongoing cryocooler activities within NASA in support of current flight projects, near-term flight
instruments, and long-term technology development. NASA programs in Earth and space science observe a wide range of
phenomena, from crop dynamics to stellar birth. Many of the instruments require cryogenic refrigeration to improve dynamic
range, extend wavelength coverage, and enable the use of advanced detectors. Although, the largest utilization of coolers over
the last decade has been for instruments operating at medium to high cryogenic temperatures (55 to 150 K), reflecting the
relative maturity of the technology at these temperatures, important new developments are now focusing at the lower
temperature range from 4 to 20 K in support of studies of the origin of the universe and the search for planets around distant
stars. NASA’s development of a 20K cryocooler for the European Planck spacecraft and its new Advanced Cryocooler
Technology Development Program (ACTDP) for 6-18 K coolers are examples of the thrust to provide low temperature cooling
for this class of missions.
Author
Cryogenic Cooling; NASA Space Programs; General Overviews; Flight Instruments; Technology Utilization
20040068226 Northrop Grumman Space Technology, Redondo Beach, CA, USA
Space Cryocoolers
Tward, Emanuel; International Thermal Detectors Workshop (TDW 2003); February 2004, pp. 6-16; In English; See also
20040068186; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document
Cryogenic coolers for use in space require low power and minimum weight. In this paper we describe the typical
requirements and performance of a number of reliable, small, efficient, low-power, vibrationally balanced coolers designed and
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