NASA Scientific and Technical Aerospace Reports

20040071043 NASA Langley Research Center, Hampton, VA, USA
Development and Ground Testing of a Compactly Stowed Scalable Inflatably Deployed Solar Sail
Lichodziejewski, David; Derbes, Billy; Reinert, Rich; Belvin, Keith; Slade, Kara; Mann, Troy; April 19, 2004; 16 pp.; In
English; AIAA Gossamer Spacecraft Forum, 10-23 Apr. 2004, Palm Springs, CA, USA
Contract(s)/Grant(s): NAS8-03046
Report No.(s): AIAA Paper 2004-4659; Copyright; Avail: CASI; A03, Hardcopy
This paper discusses the solar sail design and outlines the interim accomplishments to advance the technology readiness
level (TRL) of the subsystem from 3 toward a technology readiness level of 6 in 2005. Under Phase II of the program many
component test articles have been fabricated and tested successfully. Most notably an unprecedented section of the conically
deployed rigidizable sail support beam, the heart of the inflatable rigidizable structure, has been deployed and tested in the
NASA Goddard thermal vacuum chamber with good results. The development testing validated the beam packaging and
deployment. The inflatable conically deployed, Sub Tg rigidizable beam technology is now in the TRL 5-6 range. The
fabricated masses and structural test results of our beam components have met predictions and no changes to the mass
estimates or design assumptions have been identified adding great credibility to the design. Several quadrants of the Mylar sail
have also been fabricated and successfully deployed validating our design, manufacturing, and deployment techniques.
Author (revised)
Product Development; Solar Sails; Ground Tests
20040073445 NASA Glenn Research Center, Cleveland, OH, USA
An Introduction to Logic for Students of Physics and Engineering
Kolecki, Joseph C.; May 2004; 32 pp.; In English
Contract(s)/Grant(s): WBS-22-755-60-04
Report No.(s): NASA/TP-2004-212491; E-14037; No Copyright; Avail: CASI; A03, Hardcopy
A physicist with an engineering background, the author presents a brief tutorial on logic. In his work at NASA and in his
encounters with students, he has often found that a firm grounding in basic logic is lacking - perhaps because there are so many
other demands on people that time simply cannot be taken to really examine the roots of human reasoning. This report provides
an overview of this all-too-important subject with the dual hope that it will suffice insofar as it goes and that it will spur at
least some to further study.
Author
Logic; Hypothetical Particles; Equivalence; Mathematics; Algebra
20040074263 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Cryogenic Technology: Ongoing Developments for the Next Decade
DiPirro, Michael; New Concepts for Far-Infrared and Submillimeter Space Astronomy; April 2004, pp. 447-453; In English;
See also 20040074260; No Copyright; Avail: CASI; A02, Hardcopy
To obtain optimum sensitivity a submillimeter space observatory will require low temperature mirrors (approx. 3K) and
very low temperature detectors (< or approx. 0.1 K). Both of these temperatures have been achieved by space cryogenic
systems, but neither for a 10 year duration. Past systems used superfluid helium to provide direct cooling in the 1 to 2 K range
(IRAS, COBE, IRTS, ISO) or as an upper stage for an adiabatic demagnetization refrigerator to achieve temperatures down
to 0.06 K (Astro-E/XRS). Boiloff vapor may be used to cool an otherwise warm telescope as in the Space InfraRed Telescope
Facility (SIRTF). In SIRTF a 0.85 m telescope is cooled to 5.5 K by absorbing about 6 mW in the cold vapor. This residual
heat is due to both radiation from a helium vapor cooled outer shield at about 20 K and from conduction through a structure
mounting the cold telescope and instruments to the warm spacecraft. The boil off rate required to cool the telescope results
in a 2.6 to 5 year lifetime, depending on whether other parasitic heat sources such as thermoacoustic oscillations are also
present. A helium dewar results in a very heavy system to achieve 2 to 5 year lifetimes. For example it takes roughly 400 kg
for XRS to achieve 0.06 K for two year life with a 250 K boundary temperature, and approx. 300 kg (including thermal
shielding) for SIRTF to achieve 1.3 K for 5 year life with a 35 K boundary temperature. To go to longer duration and to lower
the weight, active cooling methods are required combined with more aggressive passive cooling techniques. It is possible, with
some development, to provide cooling for detectors to 0.05 K and telescopes and instruments to < 4 K for a 10 year mission
with a 100 kg system including power sources, structural support, and vacuum enclosures for critical portions of the
instruments.
Author
Cryogenic Equipment; Cryogenic Cooling; Astronomical Satellites
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