Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

primary issues for it’s adaptation to interstellar precursor applications include the nuclear reactor that would be required and the
engine lifetime. A propulsion system concept for the proposed Interstellar Probe mission will be described for each.
Author
Transportation; Interstellar Space; Space Missions; Space Exploration; Nuclear Electric Propulsion; Propulsion System Performance
20000067685 NASA Marshall Space Flight Center, Huntsville, AL USA
Manufacturing and NDE of Large Composite Structures for Space Transportation at MSFC
McGill, Preston, NASA Marshall Space Flight Center, USA; Russell, Sam, NASA Marshall Space Flight Center, USA; [2000];
41p; In English; 9th; 2000 ASNT Spring Conference, 29 Mar. 2000, Birmingham, AL, Birmingham, AL, USA, USA; No Copyright;
Avail: CASI; A03, Hardcopy; A01, Microfiche
This paper presents the Marshall Space Flight Center’s (MSFC’s) vision to manufacture, increase safety and reduce the cost
of launch vehicles. Nondestructive evaluations of large composite structures are tested for space transportation at MSFC. The
topics include: 1) 6 1/2 Generations of Airplanes in a Century; 2) Shuttle Safety Upgrades; 3) Generations of Reusable Launch
Vehicles; 4) RLV Technology Demonstration Path; 5) Second Generation; 6) Key NASA Requirements; 7) X-33 Elements; 8)
Future-X Pathfinder Projects and Experiments; 9) Focus Area Technical Goals; 10) X-34 Expanded View; 11) X-38 Spacecraft
with De-Orbit Propulsion Stage (DPS); 12) Deorbit Module (DM) Critical Design Review (CDR) Design; 13) Forward Structural
Adapter (FSA) CDR Design; 14) X-38 DPS CDR Design; 15) RLV Focused Propulsion Technologies; and 16) Challenges in
Technology. This paper is presented in viewgraph form.
CASI
Composite Structures; Manufacturing; Nondestructive Tests; Reusable Launch Vehicles; Space Transportation
17
SPACE COMMUNICATIONS, SPACECRAFT COMMUNICATIONS, COMMAND AND TRACKING
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20000063381 NASA Glenn Research Center, Cleveland, OH USA
Radiation Hardened, Modulator ASIC for High Data Rate Communications
McCallister, Ron, SICOM, Inc., USA; Putnam, Robert, SICOM, Inc., USA; Andro, Monty, NASA Glenn Research Center, USA;
Fujikawa, Gene, NASA Glenn Research Center, USA; June 2000; 12p; In English; 18th; Communication Satellite Systems, 10-14
Apr. 2000, Oakland, CA, USA; Sponsored by American Inst. of Aeronautics and Astronautics, USA
Contract(s)/Grant(s): NAS3-99096; RTOP 632-6E-51
Report No.(s): NASA/TM-2000-210045; E-12246; NAS 1.15:210045; No Copyright; Avail: CASI; A03, Hardcopy; A01, Microfiche
Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support
high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient
Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values.
High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA
efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint
on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency,
but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which
can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with
high power-efficiency (negligible HPA backoff).
Author
Telecommunication; Application Specific Integrated Circuits; Modulators; Power Efficiency
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