The current steady-state performance-based system studies are not adequate to evaluate certain advanced technologies for the challenges associated with meeting the transient performance requirements without better definition and control of component operating margins. Additional...

This software conducts preliminary design studies for spacecraft missions. It supports a collaborative work environment that allows multiple engineers to work simultaneously on the same design. When designing a spacecraft or mission, it is important that each engineer has concurrent...

Binary protograph codes are state-of-the-art codes over the binary field Galois Field GF(2). These codes were invented by JPL in 2003 and proposed to CCSDS (Consultative Committee for Space Data Systems) recently as a channel-coding standard for space communications. It is...

Bandwidth and power-coded modulation schemes are very desirable for many applications in high-data-rate transmission over a given allocated bandwidth. The goal is to design such coded modulation system for a given throughput with the lowest possible signal-to-noise ratio for not only a channel...

The most common way to generate a rate-compatible family of codes is puncturing. In this method, one starts with a low-rate mother code and then selectively discards some of the coded bits to arrive at higher-rate codes. This approach is simple, but is not free of problems. Specifically, the mother...

Many of the most challenging aspects of propulsion system development are related to the prediction of interacting effects among fluid loads, thermal loads, and structural deflection. A typical design practice might ignore the interaction between the physical phenomena where...

The Evolutionary Mission Trajectory Generator (EMTG) is a global trajectory optimization tool for designing interplanetary missions that perform multiple flybys and either low-thrust or high-thrust propulsive maneuvers on the way to destinations in the solar system. Some targets, such as Mars and Venus, are...

Automation and autonomy are key elements in realizing the vision for space exploration. The NASA Exploration Technology Development Program (ETDP) has been developing several core autonomy capabilities, one of which is called a procedure representation language (PRL). PRL can be automatically...

A paper describes a process for imposing safety constraints on a spacecraft trajectory design. The conventional process has the ACS (Attitude Control System) team define geometric constraints, then the NAV (Navigation) team produces a compliant thrust direction...

Accurate assessment of circuits at cold temperatures is extremely difficult due to lack of models and tools that can simulate circuit behavior at cryogenic temperatures. A library of cryogenic temperature models was built, as well as a circuit simulator that can use those models and simulate...

Atmospheric turbulences are fractional order, and because of that, it is difficult to simulate these disturbances. Past models fall short in providing sufficiently accurate simulation of atmospheric turbulence, especially at high altitudes, for control designs of high-speed atmospheric vehicles. In...

Biologically inspired autonomous and autonomic systems (AAS) are essentially about creating self-directed and self-managing systems based on metaphors such as that of the autonomic nervous system. Agent technologies have been identified as a key enabler for engineering autonomy and autonomicity in systems, both in terms of...

Dr. Vadim Smelyanskiy is a principal scientist for physics-based methods in the Exploration Technology Directorate at NASA Ames Research Center. During his tenure at NASA, he has been the principal investigator on several projects funded by NASA and other government...

Available guidance approaches for large numbers (i.e., swarms) of artificial agents are currently very limited. Swarms in nature (e.g., bees, birds, ants) typically contain hundreds to thousands of agents. The problem is how to mimic nature, and develop guidance laws for artificial (manmade)...