From previous studies, lymphocyte DNA from human leukemias and DNA from involved tissues of patients with Hodgkin's disease or Burkitt's lymphoma contain sequences that are absent from their normal counterparts. These sequences are related to those found in particulate elements associated with these neoplasias and possessing biochemical properties characteristic of RNA tumor viruses. Similar ob...

For the safe operation of a complex system like a (manned) launch vehicle, real-time information about the state of the system and potential faults is extremely important. The on-board FDDR (Failure Detection, Diagnostics, and Response) system is a software system to detect and identify failures, provide real-time diagnostics, and to initiate fault recovery and mitigation. The ERIS (Evaluation ...

Abstract The assessment of thermal loads occurring on reusable launch vehicles during the entire trajectory is essential for correct dimensioning protection system. Due to costs and limitations ground-based testing large-scale vehicles, these predictions rely intensively numerical simulations (CFD). need aero-thermal databases, as a fast-response surrogate model aero-thermodynamic heating, aris...

Activated DNA-directed DNA synthesis catalyzed by Rauscher leukemia virus (RLV) and other type C mammalian retroviral DNA polymerases is uniquely stimulated by biologically active polyamines. Cationic trypanocides may act as antagonists of polyamine function. As described here, several cationic trypanocides stimulate RLV polymerase-catalyzed DNA-directed DNA synthesis at concentrations signific...

Current methods for defining the operational support requirements of new systems are data intensive and require significant design information. Methods are being developed to aid in the analysis process of defining support requirements for new launch vehicles during their conceptual design phase that work with the level of information available during this phase. These methods will provide supp...

1 0-7803-6599-2/01/$10.00 © 2001 IEEE. Abstract— This paper presents an adaptive guidance system approach applied to hypersonic Reusable Launch Vehicles (RLVs). After an effector failure, it is assumed that the inner-closed-loop system utilizes a reconfigurable control algorithm to recover nominal maneuvering capabilities to the extent possible. However, nominal performance will typically not b...

Flexible inhibitors are generally used in solid rocket motors (SRMs) as a means to control the burning of propellant. Vortices generated by the flow of propellant around the flexible inhibitors have been identified as a driving source of instabilities that can lead to thrust oscillations in launch vehicles. Potential coupling between the SRM thrust oscillations and structural vibration modes is...

Methods exist to define the logistics support requirements for new aircraft concepts but are not directly applicable to new launch vehicle concepts. In order to define the support requirements and to discriminate among new technologies and processing choices for these systems, NASA Langley Research Center (LaRC) is developing new analysis methods. This paper describes several methods under deve...

Designers of space launch systems should be cognizant of the impact of their design assumptions on operational characteristics. Operational metrics such as turnaround time, recurring cost, and headcount are critical factors for the future viability of such systems. The results presented here are from a study that seeks to determine in what manner design approaches can improve the operability of...