There's a particular agony that hollows out your heart, waiting on a call that's late, and might never come. It's worse when you know that on the other end of the line is danger, and you're too far away to offer any measure of protection beyond your watchful waiting, which is no safety at all.
Sounds Familiar! The red plant. Once we say so, you think of volcanic eruptions... Volcanoes... Volcanoes everywhere... Eruptions... Falling rocks, and Aand Storms !!
But actually, you rarely think of how many rovers we have lost because of these troublesome guests.
The Opportunity, the longest-running Mars rover, is currently in a bad spot. It's smack in the middle of an intensifying dust storm.
You rarely think of Opportunity…
And after long sought, hard work, and intense research.
We better call it a system that has a solution for any possible problem or challenge a rove could find on Mars
Mars exhibits a main radiation exposure of 20mrad/d = 73 mGy/a. JPL reported that MARIE-measured radiation levels were two to three times greater than at the International Space Station (which is 100-200mSv/a). That is why we decided to shield our rover with a thick aluminum and lead cover.
gravity on mars is about 38% of that on Earth. So, we used the following conversion to compete the mass of our sensor and rover in general:
Mass of designed instrument on Mars= 38 * Mass of the same instrument on Earth
Mars is famous for its large, planet-wide dust storms that is why we designed a remote sensing system to avoid such disturbances. In this system, we added a Wi-Fi module to the rover so that it connects with the satellites orbiting mars in order to get the locations of dust storms occurrence by receiving a map image every 30 seconds from NASA APIs. NASA API has been used to access the Mars Trek web service either directly on JSON format or image so further image processing is required to be applied for data extraction. The rover’s board then compares it to the reference pattern of a map that is recorded at normal environment (no dust storms or so), and reserved as a reference point. Depending on this simple comparison process, we set a code that directs the rover through the track whose comparison results are (Patterns are equivalent) and moves away from the regions which have comparison results of (Patterns do not match) because if they don’t match then the new pattern represents a map image that has a dust storm. AND WE DON”T WANT TO MEET SUCH GUEST. Moreover, if the dust storm is too near, that the rover has no escape but meet it, our proposed prototype is to be shielded by an instruction that the storm is too near (at distance less than 5 Km). The rover gets a cover around it and sends a signal to the space station (with the time and the specific location) that it will be in a stand-by system until the storm goes away. Something the space station observes, and the rover is not switched on again and doesn’t go out of the shield until the space center sends a signal to do so when they observe by the satellites that the storm has gone away from the location which the rover has sent right before it entered the stand-by mood. As a result we keep the rover safe, secure, and most importantly controllable.
As we know, Mars is inflamed and eruptive. So, you never rule out that a rock would attack you from nowhere. But we took our precaution, and after a literature review about sensors, we decided to use infra-red sensors that rotate on a 360 degrees with an active long range of 40 Km. this enables the rover to take action in a penalty of time before the rock falls on it. Also, based on the distance reading from the infra-red sensor, and using the gravity on mars which is 3.7 m/s2 we are able to detect the velocity by which the rock is falling towards the rover. As a proof of concept, we simulated this system in a small-scale prototype with an infra-red sensor of active range 120 cm. Further, we used an infra-red sensor because it operates on electromagnetic waves which require no medium to travel through and wouldn’t be disturbed by the thin atmosphere on Mars.
A - Environment on Mars versus Earth:
Mars has no protective magnetosphere, as Earth does. Scientists believe that at one time, Mars also experienced convection currents in its core, creating a dynamo effect that powered a planetary magnetic field. However, roughly 4.2 billion year ago – either due to a massive impact from a large object, or rapid cooling in its core – this dynamo effect ceased.
As a result, over the course of the next 500 million years, Mars atmosphere was slowly stripped away by solar wind. Between the loss of its magnetic field and its atmosphere, the surface of Mars is exposed to much higher levels of radiation than Earth. And in addition to regular exposure to cosmic rays and solar wind, it receives occasional lethal blasts that occur with strong solar flares.
NASA's 2001 Mars Odyssey spacecraft was equipped with a special instrument called the Martian Radiation Experiment (or MARIE), which was designed to measure the radiation environment around Mars. Since Mars has such a thin atmosphere, radiation detected by Mars Odyssey would be roughly the same as on the surface.
Through the span of around year and a half, the Mars Odyssey test distinguished continuous radiation levels which are 2.5 times higher than what astronauts encounter on the International Space Station – 22 millirads per day, which works out to 8000 millirads (8 rads) every year. The rocket likewise recognized 2 sun based proton occasions, where radiation levels crested at around 2,000 millirads in a day, and a couple of different occasions that got up to around 100 millirads.
The gravity of Mars is a natural phenomenon, due to the law of gravity, or gravitation, by which all things with mass around the planet Mars are brought towards it. It is weaker than Earth's gravity owing to the planet's smaller mass. The average gravitational acceleration on Mars is 3.72076 ms−2 (about 38% of that of Earth).
So, we used the following conversion to compete the mass of our sensor and rover in general:
Mass of designed instrument on Mars= 38*Mass of the same instrument on Earth
Average -81 degrees F
Mars is farther from the Sun than the Earth, so, as you would expect, the temperature of Mars is colder. For the most part it is very cold on Mars. The only exception is during the summer days close to or at the equator. Even at the equator, the night time temperatures fall well below zero. On those summer days, it can be around 20 degrees Celsius then plummet to -90 C at night.
Mars follows a highly elliptical orbit, so temperatures vary quite a bit as the planet travels around the Sun. Since Mars has an axial tilt similar to Earth’s (25.19 for Mars and 26.27 for Earth), the planet has seasons as well. Add to that a thin atmosphere and you can see why the planet is unable to retain heat. The Martian atmosphere is over 96% carbon dioxide. If the planet had an atmosphere to retain heat, the carbon dioxide would cause a greenhouse effect that would heat Mars to jungle like temperatures.
The relative humidity is high and the available water vapor is approximately 100 perceptible microns, is the equivalent of the drier parts of the Atacama Desert in Chile.
4) Dust storms:
Mars is famous for its large, planet-wide dust storms. Mars has an atmosphere which is much thinner than the atmosphere on Earth, but which still creates winds. When these winds pick up the fine, dry particles of dust on Mars, a dust storm can occur. Most dust storms cover an area for a few days and carry small particles of dust at speeds of 33 to 66 miles per hour. Sometimes, though rarely, dust storms on Mars can be fierce enough to cover the entire planet in a dusty haze for weeks. Our plan when a dust storm blow.
B- Infra-red sensors:
An infrared sensor is an electronic instrument that is used to sense certain characteristics of its surroundings. It does this by either emitting or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion.
Infrared waves are not visible to the human eye. In the electromagnetic spectrum, infrared radiation can be found between the visible and microwave regions. The infrared waves typically have wavelengths between 0.75 and 1000µm.
The infrared spectrum can be split into near IR, mid IR and far IR. The wavelength region from 0.75 to 3µm is known as the near infrared region. The region between 3 and 6µm is known as the mid-infrared region, and infrared radiation which has a wavelength greater higher than 6µm is known as far infrared.
1/ Thermal infrared sensors – use infrared energy as heat. Their photo sensitivity is independent of the wavelength being detected. Thermal detectors do not require cooling but do have slow response times and low detection capabilities. .
2/ Quantum infrared sensors – provide higher detection performance and faster response speed. Their photo sensitivity is dependent on wavelength. Quantum detectors have to be cooled in order to obtain accurate measurements.
That is why we chose the quantum infrared sensor in order to make our design more efficient.
1/ Planck’s radiation law: Every object at a temperature T not equal to 0 K emits radiation.
2/ Stephan Boltzmann Law: The total energy emitted at all wavelengths by a black body is related to the absolute temperature.
3/ Wein’s Displacement Law: Objects of different temperature emit spectra that peak at different wavelengths.
C- Remote sensing
Remote Sensing is the art and science of acquiring information about the earth surface without having any physical contact with it. This is done by sensing and recording of reflected and emitted energy.
In the process of Remote Sensing involves an interaction between the incoming radiation and interest of target. This is done by using imaging and non-imaging system.
a. Energy Sources:
The first and most important requirement for a Remote Sensing system is an ideal energy source or illumination which provides electromagnetic radiation to the Target interest.
b. Atmosphere and Radiation:
As the energy traveling from its source to Earth surface, it will come in contact with atmosphere when it passes through. This is also happening when the energy from target reflected bake to sensor.
c. Interaction with the Target and Recording of the Reflected Energy
Once the energy is passed through the atmosphere, it interacts with the target object and depending upon the physical and chemical properties of the Target the energy is reflected or emitted back the Sensor collect and record the Electromagnetic radiation.
d. Transmission and Ground level Processing
After the energy sensed it has to be transmitted in the form of electronic signals to the ground stations for processing and generate the output as image (Hard copy/Soft copy). The processing involves various steps that we will discuss in later.
e. Interpretation, Analysis and Application.
The processed image is interpreted visually and digitally using various interpretation Techniques to extract the information.
The final step is that we are applying the extracted information on various fields of our studies. It may reveal some new information about which the target. The data we gained through Remote Sensing may not be able to collect it through other conventional methods. The applications are infinite.
The five headings are the major elements in Remote Sensing from beginning to end. The following chapters will be covering these main headings.
The first and most important component of Remote Sensing is the Energy source to illuminate the Target. The energy is in the form of Electromagnetic Radiation. It is either natural originating from the Sun or earth by emission, or by artificial means. Electromagnetic energy refers to all the energy that moves with the velocity of light in a harmonic wave pattern.EMR consists of an Electrical field and Magnetic field. The electrical field varies magnitude in a direction perpendicular to the direction in which the radiation is travelling and magnetic field oriented to the right angles to the electrical field.
When the incoming solar radiation passes through the atmosphere it may come in contact with atmospheric particles and gases, leads to the mechanisms of scattering and absorption. The gases absorb the Electromagnetic radiation at specific wavelengths called absorption bands. However the high interviewing transmittance regions are often known as Atmospheric Windows.
So far, throughout this chapter we discussed various Remote Sensing techniques. There are two types of Remote Sensing Systems namely Active and Passive sensing. Passive sensing means the sensor uses Sun’s energy as the source of illumination and active sensing means the sensor emitting the energy to the target and collecting the reflected energy. Some examples of active sensors are fluorosensor and Synthetic Aperture Radar (SAR).
The main disadvantage of passive sensors is that they can collect or detect objects in the day time only because sun’s illumination is not there at night, however they can record the naturally emitted energy like Thermal infrared. On the other hand Active sensor gives own energy for illumination so it enables to detect and record the images at any time. They are weather independent also; artificial microwaves can penetrate clouds, light and shadow. But Passive sensors are not weather independent. Radar signals can penetrate into vegetation and soil and even can give you the surface information at mm to m depth level at the same time major disadvantage is that radar signals do not contain any spectral characters while Passive Remote Sensing signals have spectral characters. Unlike active sensors passive sensor have the ability to produce fine resolution image. Active Remote sensors are cost intensive also when compared to passive sensor.
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