Engineering topics
Publications and source records attributed to Baker, V..
ASE has successfully demonstrated that a spacecraft can be driven by science analysis and autonomously controlled. ASE is available for flight on other missions. Mission hardware design should consider ASE requirements for available onboard data storage, onboard memory size and processor speed.
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The Autonomous Sciencecraft Experiment (ASE) has been selected for flight demonstration by NASAs New Millennium Program (NMP) as part of the Space Technology 6 (ST6) mission. NASA has identified the development of an autonomously operating spacecraft as a necessity for an expanded program of missions exploring the Solar System. The versatile ASE spacecraft command and control software, image formation software, and science processing software will be uploaded to the Earth Observer 1 (EO-1) spacecraft in early 2004 to detect surface modification related to volcanism, ice formation and retreat, and flooding.
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In mid-2003, we will fly software to detect science events that will drive autonomous scene selectionon board the New Millennium Earth Observing 1 (EO-1) spacecraft. This software will demonstrate the potential for future space missions to use onboard decision-making to detect science events and respond autonomously to capture short-lived science events and to downlink only the highest value science data.
The centers work of Anderson et al. (2001) [1] identified two prominent centers in the Tharsis region, Syria Planum and Alba Patera (Stage 2 and Stage 4 respectively). Because of their perceived influence on the geologic and possible paleoclimatic histories of Mars, Mars Orbiter Laser Altimetry (MOLA) along with published stratigraphic and paleotectonic information (including the centers information) were analyzed using Geographic Information Systems (GIS) to perform a comparative investigation of their strain histories through time. This investigation highlights their similarities and distinctions, including their topographic and morphologic signatures, deformational extent, and intensities and durations of activity.
The search for surface and near-surface liquid water on Mars is a central part of current and planned future exploration, which include radar sounders on Mars Express and MRO and proposed synthetic aperture radar (SAR) imagers. In order to penetrate sand and dust cover, these systems are proposed for longer wavelengths (e.g, from [2]: 24 cm / L-band and 74 cm / P-band) than those considered optimal for the detection of soil moisture (6 cm / C-band). However, there has been some success in detecting soil moisture at longer wavelengths. Given the size and mass constraints for Mars missions, the optimization of radar instrument parameters for meeting science objectives, such as searching for liquid water, is essential. In this on-going study, we are using repeat coverage of Mars analog sites with multifrequency (C, L and P band) airborne radar and ground truth soil sample data to assess the detectability of soil moisture.
NASA has identified the development of an autonomously operating spacecraft as a necessity for an expanded program of missions exploring the Solar System. The Autonomous Sciencecraft Experiment (ASE) has been selected for flight demonstration by NASA s New Millennium Program (NMP) as part of the Space Technology 6 (ST6) mission. ASE is scheduled to fly on the US Air Force Research Laboratory (AFRL) Techsat-21 constellation in 2006. Tech- Sat-21 consists of three satellites flying in a variable-geometry formation in Earth orbit. Each satellite is equipped with X-band Synthetic Aperture Radar, yielding high spatial resolution images (approx. 3 m) of the Earth s surface. The constellation will fly at an altitude of 550 km, in a 35.4 inclination circular orbit, yielding exact repeat-track observations every 13 days. Prior to full deployment, elements of the versatile ASE spacecraft command and control software, image formation software and science processing software will be utilized and tested on two very different platforms in 2003: AirSAR and EO-1 (described below). Advantages of Autonomous Operations: ASE will demonstrate advanced autonomous science data acquisition, processing, and product downlink prioritization, as well as autonomous spacecraft command and control, and fault detection. The advantages of spacecraft autonomy are to future missions include: (a) making the best use of reduced downlink; (b) the overcoming of communication delays through decisionmaking in situ, enabling fast reaction to dynamic events; (c) an increase of science content per byte of returned data; and (d) an avoidance of return of null (no-change/no feature) datasets: if there is no change detectable between two scenes of the same target, there is no need to return the second dataset.
The Autonomous Sciencecraft Constellation-Techsat 21 mission is a NASA New Millennium Program mission selected for flight in 2004. ASC will autonomously perform science analyses of X-band radar data, while in Earth orbit. Additional information is contained in the original extended abstract.
It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing.
The Autonomous Sciencecraft Constellation flight demonstration (ASC) will fly onboard the Air Forces's TechSat-21 constellation. Demonstration of its capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreadable without this technology.
Preliminary analysis of Amazonian structures indicate that Mars may still be tectonically active. Additional information is contained in the original extended abstract.
Paleotopographic reconstructions reveal the potential existence of an enormous Noachian drainage basin in the eastern part of the Tharsis region of significant geologic and paleohydrologic implications. Additional information is contained in the original extended abstract.
The concept of the hydrological cycle is one of the greatest achievements in the understanding of nature. Leonardo da Vinci seems to have held two concurrent views of the cycle: an external process in which evaporation from ponded areas leads to precipitation and runoff from the land; and an internal process in which subsurface pressures from within the Earth force water upward. Endogenetic hypotheses for valley genesis on Mars maintain the necessary prolonged ground water flows by hydrothermal circulation associated with impact cratering or with volcanism. Ocean formation on Mars was episodic, mostly evidenced by the latest episodes. Coincident cataclysmic flood discharges to the northern plains, probably triggered by Tharsis volcanism, would lead to immense consequences. Potential volumes of ponded water are summarized. The outflow channels have a complex history of flooding events over a prolonged period of planetary history. It is hypothesized that episodic outbursts of concurrent discharge was triggered by planetary scale volcanism. The consequences of such episodes are summarized.
Exhaust nozzles for expendable supersonic turbojet engine missile propulsion systems are required to be simple, short and compact, in addition to having good broad-range thrust-minus-drag performance. A series of convergent-divergent nozzle scale model configurations were designed and wind tunnel tested for a wide range of free stream Mach numbers and nozzle pressure ratios. The models included fixed geometry and simple variable exit area concepts. The experimental and analytical results show that the fixed geometry configurations tested have inferior off-design thrust-minus-drag performance in the transonic Mach range. A simple variable exit area configuration called the Axi-Quad nozzle, combining features of both axisymmetric and two-dimensional convergent-divergent nozzles, performed well over a broad range of operating conditions. Analytical predictions of the flow pattern as well as overall performance of the nozzles, using a fully viscous, compressible CFD code, compared very well with the test data.