Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFlight in the Jovian Stratosphere. Engine Concept and Flight Altitude Determination
140
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
An effective method for detailed observation of the Solar System planets is the use of vehicles that can perform flight in their atmospheres, with the most promising of them being Flyers (aircraft for other planets atmospheres). Besides the advantage of probing the atmosphere directly, they have the ability to fly on selected direction and altitude, making them suitable for collecting information over large areas. Equipping the Flyer with nuclear propulsion will allow it to conduct flight for months without the need of combustible fuel or oxidizer to be carried on board. Among the planets of the Solar System and their satellites, Jupiter is a viable target for exploration, since it features thick atmosphere suitable for aerodynamic flight, there is no solid surface that can be contaminated after end of the mission, and the atmospheric data for designing a Flyer is readily available. This paper proposes a mathematical model for evaluating the thrust, the lift and the maximum allowable mass for horizontal steady flight as functions of the altitude and different heat chamber temperatures.
rate research
Read More
This paper discusses the analysis performed on a supersonic ramjet engine inlet for flight in the atmosphere of Jupiter. Since the Jovian atmosphere lacks oxygen, the thrust will be generated by nuclear fission heating in the heat chamber. The first task to solve in the design in a ramjet engine is to design the supersonic inlet. The developed design methodology utilizes theoretical calculations and Computational Fluid Dynamics (CFD) simulations. The analytical model used to calculate the gas parameters in front of the heat chamber, and the CFD analysis, used to define the inlet geometry, are discussed. The results from the analytical model and CFD are compared and used for validation of the design approach. The calculated pressure losses and the mass flow allow the determination of important parameters required for the design of the aircraft, such as the reactor power, the thrust, the maximum mass, and the overall external dimensions.
The Terrestrial Planet Finder Coronagraph (TPF-C) mission presented here is an existence proof for a flagship-class internal coronagraph space mission capable of detecting and characterizing Earth-like planets and planetary systems at visible wavelengths around nearby stars, using an existing launch vehicle. TPF-C will use spectroscopy to measure key properties of exoplanets including the presence of atmospheric water or oxygen, powerful signatures in the search for habitable worlds.
The LOng Range Reconnaissance Imager (LORRI) is a panchromatic (360--910 nm), narrow-angle (field of view = 0.29 deg), high spatial resolution (pixel scale = 1.02 arcsec) visible light imager used on NASAs New Horizons (NH) mission for both science observations and optical navigation. Calibration observations began several months after the NH launch on 2006 January 19 and have been repeated annually throughout the course of the mission, which is ongoing. This paper describes the in-flight LORRI calibration measurements, and the results derived from our analysis of the calibration data. LORRI has been remarkably stable over time with no detectable changes (at the 1% level) in sensitivity or optical performance since launch. By employing 4 by 4 re-binning of the CCD pixels during read out, a special spacecraft tracking mode, exposure times of 30 sec, and co-addition of approximately 100 images, LORRI can detect unresolved targets down to V = 22 (SNR=5). LORRI images have an instantaneous dynamic range of 3500, which combined with exposure time control ranging from 0ms to 64,967 ms in 1ms steps supports high resolution, high sensitivity imaging of planetary targets spanning heliocentric distances from Jupiter to deep in the Kuiper belt, enabling a wide variety of scientific investigations. We describe here how to transform LORRI images from raw (engineering) units into scientific (calibrated) units for both resolved and unresolved targets. We also describe various instrumental artifacts that could affect the interpretation of LORRI images under some observing circumstances.
The ESA PLATO space mission is devoted to unveiling and characterizing new extrasolar planets and their host stars. This mission will encompass a very large field of view, granting it the potential to survey up to one million stars depending on the final observation strategy. The telemetry budget of the spacecraft cannot handle transmitting individual images for such a huge stellar sample at the right cadence, so the development of an appropriate strategy to perform on-board data reduction is mandatory. We employ aperture photometry to produce stellar light curves in flight. Our aim is thus to find the mask model that optimizes the scientific performance of the reduced data. We considered three distinct aperture models: binary mask, weighted Gaussian mask, and weighted gradient mask giving lowest noise-to-signal ratio, computed through a novel direct method. An innovative criterion was adopted for choosing between different mask models. We designated as optimal the model providing the best compromise between sensitivity to detect true and false planet transits. We determined the optimal model based on simulated noise-to-signal ratio and frequency of threshold crossing events. Our results show that, although the binary mask statistically presents a few percent higher noise-to-signal ratio compared to weighted masks, both strategies have very similar efficiency in detecting legitimate planet transits. When it comes to avoiding spurious signals from contaminant stars however the binary mask statistically collects considerably less contaminant flux than weighted masks, thereby allowing the former to deliver up to $sim$30% less false transit signatures at $7.1sigma$. Our proposed approach for choosing apertures has been proven to be decisive for the determination of a mask model capable to provide near maximum planet yield and substantially reduced occurrence of false positives.
The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2 mission that was launched in November 2009. LYRA acquires solar irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ray to MUV, that have been chosen for their relevance to solar physics, space weather and aeronomy. In this article, we briefly review the design of the instrument, give an overview of the data products distributed through the instrument website, and describe the way that data are calibrated. We also briefly present a summary of the main fields of research currently under investigation by the LYRA consortium.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
