- API data.nasa.gov | Last Updated 2018-07-19T07:37:24.000Z
One of the biggest problems facing spaceflight today is the accumulation of orbital debris because it threatens the successful operation and lifespan of existing satellites. The predominant cause of orbital debris is the jettisoning of launch vehicle upper stages after their usefulness is over once a rocket reaches orbit altitude. While their orbit slowly decays, these obsolete upper stages then share an orbit with valuable satellites presenting a danger to those satellites by either hitting them or hitting other rocket bodies and breaking into smaller pieces which can be just as dangerous but become much harder to track. These collisions potentially add an exponentially growing number of debris in orbit. One way to reduce the number of rocket bodies in orbit is to have a drag device connected to the upper stage of the launch vehicle that deploys once it is jettisoned from the payload. The intent of this device is to increase atmospheric drag and thus accelerate deorbit. By reducing the time debris is in orbit we will reduce the amount of debris thereby reducing the threat to satellites. When designing this device, it is important to minimize the packaged mass and volume of the final design to minimize the impact on the launch vehicle payload capacity. This project requires background research to accumulate data on upper stage sizes and masses, final orbits, and the current time it takes them to deorbit. An orbital mechanics review would be required to determine the effectiveness of the drag device compared to size. This research will help to develop initial requirements to start the design phase of the device. The design depends greatly on the materials and the dynamics of the device. It requires a flexible membrane to allow packaging, and foldable booms to stiffen the membrane once it is deployed. These will most likely be made from composite materials. The dynamics will be determined through computer models and simulations, followed by the building of various prototypes to test the deployment and folding configurations. Testing the deployment will occur in three phases. The first is by offloading the gravity within the lab to facilitate quick design iterations based on test results. The second is testing the deployment in a reduced gravity aircraft for higher fidelity testing. Finally, it will be tested in space on either a cubesat or launch vehicle upper stage. The results of each round of testing will allow the design and models to be improved. The research required for this device applies to the technology area 12.3 Mechanical Systems because of the subsection 12.3.1 Deployables, Docking and Interfaces. This lower level element emphasizes the importance of being able to overcome the constraints of launch vehicle fairing size. The area of deployable space structures is still a fairly new research topic with a lot of room for development and study. This project will definitely help to increase the body of knowledge on the dynamics, design techniques, and testing techniques. The necessity for a reliable restraint/release mechanism will benefit development research, as well, as this is a very important aspect of any deployment system. The flexible sail material will require development and research into how flexible membranes stow and respond to the environment of space. Finally, it is possible that the goal of this project will necessitate a fairly large deployable, which would increase research data for large lightweight stiff deployables.
Lightweight and Compace Multifunction Computer-Controlled Strength and Aerobic Training Device, Phase Idata.nasa.gov | Last Updated 2018-07-19T09:03:34.000Z
TDA Research proposes to develop a computer-controlled lightweight and compact device for aerobic and resistive training (DART) to counteract muscular atrophy and bone loss and to improve the overall wellness of astronauts operating in microgravity. The DART will be able to provide resistive loads up to 350 lbf and will accurately simulate the load profile of a mass in a 1-g environment. It will also be capable of applying custom load profiles such as eccentric overloading. In aerobic training mode, the DART will simulate the loads of a rowing machine with loads up to 175. The system will computer-controlled and can automatically calibrate to a user's range of motion. The total weight of the device will be less than 20 lbs and have a compact form factor to enable integration into a small crew module. By using a regenerative energy recovery system, the average power consumption of the DART will be less than 100 W during an exercise session. TDA is able to build on previous experience building exercise equipment for NASA and develop the DART in a short timeframe. TDA will prove the feasibility of providing effective aerobic and resistive training with a single device that is lightweight and compact in Phase I. At the end of Phase I a prototype will be delivered to NASA for evaluation. In Phase II we will advance the technology and provide the second generation prototype to NASA for testing on the International Space Station.
- API data.nasa.gov | Last Updated 2018-07-19T07:45:37.000Z
Physical Sciences Inc. (PSI) proposes to develop new solar cells based on a ferroelectric semiconductor absorber material that can yield a 30% increase in efficiency and a 20% increase in specific power compared with current triple-junction III-V cells. These gains will be realized by exploiting a unique charge separation mechanism in ferroelectrics that enables open-circuit voltages many times the band gap, leading to maximum power conversion efficiencies exceeding the conventional Shockley-Queisser limit (33%). PSI and team members will create photovoltaic cells based on Earth-abundant SnS stabilized in a ferroelectric state by epitaxial strain engineering. By combining above-gap cell voltages with the high absorption coefficient (<1 x 105 cm-1 at 500 nm), low density (5.22 g/cm3), and ideal band gap (1.1 eV) of SnS, a mass-specific power density of 120 kW/kg (mass of absorber material, 1 um absorber thickness) is projected. In addition, a maximum cell efficiency of >45% is anticipated to be achievable. Importantly, these cells will also offer improved radiation resistance due to the reduced carrier diffusion lengths required by the unique ferroelectric charge separation mechanism. During Phase I, PSI, guided by first-principles calculations conducted by the PARADIM Center at Cornell University, will demonstrate room-temperature ferroelectric ordering in SnS through epitaxial strain engineering. During Phase II, PSI and Lawrence Berkeley National Laboratory will demonstrate the potential of the proposed absorber by achieving above-band gap open-circuit voltages in prototype cells. During a Phase III effort, the efficiency of these cells will be increased to a target value of 45% through reduction of intrinsic defects, leading to substantial improvements in cell size, weight, and power output.
- API data.nasa.gov | Last Updated 2018-09-07T17:46:54.000Z
Scientific/Technical/Management Science Goals and Objectives: A major goal of the NASA planetary space program has been the search for life in our solar system. On Mars, this effort has been focused on the successful search for water and habitability. The next step will be searching specific locations for signs of past life. One of the most promising places are the hydrothermal sinter deposits in the Nili Patera caldera of the Syrtis Major volcano. These deposits would have been long-lived, with the suitable environmental conditions and provide a well-mapped feature for a targeted mission. To prepare for this type of mission, we propose a series of experiments and field operations to develop the required methodologies. Operating at an extinct hot spring deposit in a Martian analog and extreme life environment in Iceland, we will collect samples and in-situ measurements to determine the resolutions and data sets required to answer the key mission objectives. We will also test trafficability to determine the spacecraft capabilities required for mission success. The proposed advancements break down into the categories of Science, Science Operations and Technology. Science objectives will focus building on the extensive set of terrestrial literature to answer questions specific to this mission. For example, how do we identify all potential signs of life preserved in the sinters and how to sinters record signs of environmental and volcanic properties. Specific to this proposal will be to understand what spacecraft instruments will be required to answer these questions. Science Operations will focus on the suite of instruments needed to operate together to answer the mission goals and what type of samples and mobility will be required for success. The Technology section will be to develop the methods to meet the requirements determined by the science effort. This includes sample collection and handling methodology and determining a plan to develop currently available field instruments into planetary capable versions. Methodology: Dr. Skok will lead a diverse team of hydrothermal, biological and instrumental experts to study a comparable hot spring deposit in Iceland to examine all the potential mission issues and scenarios, along with sample requirements. A combination of lab analysis of collected samples and in-situ deployment of field instruments will be used to prepare for this future mission. Relevance to Planetary Science and Technology Through Analog Research: This proposal meets the stated PSTAR goal of funding projects to planetary analog sites to develop the technologies and methodologies required for future missions, especially to extreme environments. Hot spring environments are key habitats on Earth and provide a planetary independent energy source and habitable zone.
- API data.nasa.gov | Last Updated 2018-07-19T08:28:13.000Z
Managing teams of unmanned vehicles is currently time-consuming and labor intensive. There needs to be a way to control multiple UAV teams with minimal human oversight. The proposed innovation builds on and combines several technologies we have developed to create an architecture and set of software methods that will achieve this goal, significantly advancing the state of the art. The proposed innovations are based on our NASA-funded Aurora planning, resource allocation, and scheduling framework, which has proved optimal in many, many diverse domains, including UAV scheduling; a Probabilistic RoadMap Planner (PRMP) to plan detailed real-time UAV routes to rapidly satisfy and optimize a large number of simultaneous constraints and objectives; the asynchronous consensus-based bundle algorithm (ACBBA) for UAV-to-UAV task negotiation; and the concept of a play (from sports) represented using behavior transition networks (BTNs). The ultimate goal of this proposed effort is to allow intelligent UAV team coordination and control in an intelligent, predictable, and robust way, with little cognitive load on the human users. This will require intelligent real-time planning, role allocation, negotiation, and detailed path planning and, when communication is not possible, autonomous, intelligent, adaptive behavior by the UAVs. In Phase I, we will develop the required AI techniques to automate all aspects of intelligently executing, recommending, and/or automatically selecting appropriate plays, robustly assigning roles and planning routes, and adaptively executing each role, robustly and predictably in environments with varying levels of uncertainty. We will design the ultimate system and, to absolutely prove its feasibility, prototype all aspects of it in Phase I on *actual, physical UAVs*.
Integrated SiC Super Junction Transistor-Diode Devices for High-Power Motor Control ModulesOoperating at 500 C, Phase Idata.nasa.gov | Last Updated 2018-07-19T11:07:58.000Z
Monolithic Integrated SiC Super Junction Transistor-JBS diode (MIDSJT) devices are used to construct 500<sup>o</sup>C capable motor control power modules for direct integration with the exploration rovers required to operate in Venus-like environments. The Phase I of this proposed work will focus on the integrated MIDSJT device development and high-temperature packaging. Phase II will focus on the integration of the MIDSJT devices to construct full 3-Phase Inverter Motor Control Modules. Although SiC is the semiconductor material of choice for fabricating high-temperature (> 150 <sup>o</sup> C) power electronics, existing SiC MOSFET and JFET based transistor device technologies perform poorly at temperatures exceeding 200 <sup>o</sup> C. The proposed gate oxide-free Integrated MIDSJT device technology will overcome several problems associated with existing SiC device technologies by: (A) exhibiting desirable normally-OFF operation yet best-in-class on-state characteristics at temperatures as high as 500 <sup>o</sup> C, (B) eliminating parasitic inductances/capacitances associated with interconnecting discrete devices, and (C) eliminating high-temperature gate oxide reliability issues. Special device designs and fabrication processes will be investigated in this work for reliable device operation at 500 <sup>o</sup> C. Novel power device packaging techniques in the areas of power substrate, die-attach, chip metallization and wire bonds will be explored to demonstrate reliable module operation at 500 <sup>o</sup> C after several thermal cycles.
- API data.nasa.gov | Last Updated 2018-07-19T04:47:22.000Z
This data set contains CODMAC level 3 cometary, calibration, and instrument checkout data acquired by the Rosetta Orbiter ALICE UV Spectrometer during the first commissioning phase of the Rosetta mission, which occurred March 5, 2004 to June 6, 2004.
- API data.nasa.gov | Last Updated 2018-09-07T17:39:46.000Z
<p>Future astrophysics missions require efficient, low-temperature cryocoolers to cool advanced instruments or serve as the upper stage cooler for sub-Kelvin refrigerators. Potential astrophysics missions include Lynx, the Origin Space Telescope, and the Superconducting Gravity Gradiometer. Cooling loads for these missions are up to 300 mW at temperatures of 4 to 10 K, with additional loads at higher temperatures for other subsystems. Due to low jitter requirements, a cryocooler with very low vibration is needed for many missions. In addition, a multi-stage cooler, capable of providing refrigeration at more than one temperature simultaneously, can provide the greatest system efficiency with the lowest mass. Turbo-Brayton cryocoolers have space heritage and are ideal for these missions due to negligible vibration emittance and high efficiency at low temperatures. The primary limitation in implementing Brayton cryocoolers at temperatures below 10 K has been the development of high efficiency turbines. On the proposed program, Creare plans to leverage recent developments in gas bearing technology and low-temperature alternators to realize a high-efficiency, low-temperature turbine. On the Phase I project, we will perform a proof-of-concept demonstration of the turbine technology at temperatures down to 4 K. On the Phase II project, we will build and demonstrate an advanced low-temperature turbine at temperatures of 4 to 10 K.</p>
- API data.nasa.gov | Last Updated 2018-08-02T15:25:24.000Z
This grouping contains the incompressible-flow cases from the 1980-81 Data Library.
- API data.nasa.gov | Last Updated 2018-07-19T08:38:04.000Z
<p>We propose to enhance GSFC’s interplanetary mission design capability by designing a fully automated multi-spacecraft multi-objective interplanetary global trajectory optimization transcription. Advanced trajectory design technologies including the ability to design Distributed Spacecraft Missions (DSMs) are attracting increased interest but no mission design tool is currently capable of performing mission and systems design/optimization for an interplanetary DSM. This effort will deliver a software prototype capable of building the optimal design of a DSM-class mission where multiple spacecraft depart to the heliocentric regime from the same launch vehicle to perform coordinated science. This new capability will lay the groundwork for a follow-on proposal to implement this new capability into NASA Goddard's Evolutionary Mission Trajectory Generator (EMTG) where it will enable new announcements of opportunity for Distributed Spacecraft Missions.</p>