Interview Questions.

Q1. What Is A Satellite ?

Circling the earth, high above our heads, satellites are messengers and observers in the sky. They relay phones calls, watch the weather, manual ships and aircrafts and perform duties that are impossible on the ground.

Q2. What Are Image Channels?

The satellites typically test the earth using distinct wave lengths (channels). Current INSAT geostationary meteorological satellites have three channel imager with the following channels:

VISIBLE wavelengths (0.55 - 0.Seventy five um) (pondered solar radiation).

IR (thermal infra-pink) (10.Five - 12.Five um). (emission channel. Each factor on the earth emits radiation in share to its hotness/coldness. So this channel offers a thermal picture of the earth)

WV (water-vapour) (five.7 - 7.1 um). (This is also an emission band. The image shows differences in water vapour absorption inside the surroundings).

Q3. What Is Satellite Orbit ?

A satellite tv for pc's orbit is the curved course it follows round earth. The pull of gravity is more potent towards the earth, so a satellite tv for pc in a low orbit need to tour quicker than one in a geostationary orbit.

Q4. What Is Earth Observation Satellite?

Earth statement satellites are satellites particularly designed to observe Earth from orbit, much like reconnaissance satellites however supposed for non-navy makes use of inclusive of environmental tracking, meteorology, map making etc. Geostationary satellites hover over the identical spot, imparting non-stop monitoring to a portion of the Earth’s floor. Polar orbiting satellites provide worldwide coverage, but only two times per day at any given spot.

Q5. What Are The New Geostationary Satellites That Will Be Launched By India?

INSAT –3-d meteorological geostationary satellite tv for pc will be released within the latter 1/2 of 2009 with the aid of ISRO.

Q6. Where Can I Find The Time On Satellite Pictures? What Time Zone Is This?

The date and time stamps are located at the top or bottom of each picture, at the side of other information. For instance, G-10 IMG 01 three Jun 00 TIME=00:30UTC RES=4km NWS/WR=SSD, is a typical date-time stamp which seems on satellite pix. The date and time, coloured blue in the above instance, is in Universal Coordinated Time (UTC). UTC is also referred to as Greenwich Mean Time (GMT) or Zulu Time (Z). Along the West Coast, we're about eight hours in the back of the UTC at some stage in Pacific Standard Time (PST).

During Daylight Saving Time (PDT), from mid April thru mid October, we're about7 hours at the back of the UTC. In the instance above, it’s June third 2000, half-hour past nighttime in Greenwich England. In order to get nearby time, you subtract7 hours to get June second 2000, 5:30PM PDT. The subsequent calendar day has already started out in Greenwich England!

Q7. Polar Orbiting Satellites ?

Due to the rotation of the Earth, it's far feasible to combine the advantages of low-altitude orbits with worldwide coverage, the use of close to-polar orbiting satellites, that have an orbital plane crossing the poles.

These satellites are launched into orbits at excessive tendencies to the Earth's rotation (at low angles with longitude strains), such that they pass throughout high latitudes close to the poles.

Q8. Explain Weather Satellite?

Weather Satellite is a sort of satellite that is often used to screen the climate and weather of the Earth. Satellites may be both polar orbiting, seeing the identical swath of the Earth each 12 hours, or geostationary, hovering over the identical spot on Earth with the aid of orbiting over the equator while shifting at the rate of the Earths rotation. These meteorological satellites, but, see more than clouds and cloud systems. City lighting, fires, results of pollutants, auroras, sand and dirt storms, snow cover, ice mapping, limitations of ocean currents, energy flows, and so on., are different styles of environmental records collected the use of climate satellites.

Q9. What Is A Geostationary Satellite?

Geostationary satellites are positioned at an peak above the earth approximately 36000 Km. At this top they rotate around the earth on the same velocity as the earth rotates round its axis, so in impact final stationary above a factor on earth (commonly directly overhead the equator).

As they continue to be desk bound they may be perfect to be used as communications satellites and also for remote imaging as they can repeatedly scan the equal factors on this planet underneath them.

Polar Orbiting satellites through assessment have a miles decrease orbit, transferring across the earth pretty swiftly, and scanning different regions of the earth at noticeably infrequent intervals.

Q10. What Is Tether Satellite?

Tether satellite tv for pc is a satellite tv for pc connected to any other with the aid of a skinny cable known as a tether. The space tether concept had its foundation inside the overdue 1800s. The concept have become extra popular in the 1960s, and sooner or later NASA examined the feasibility of the concept and gave path to the look at of tethered structures, in particular tethered satellites.

Q11. How Do I Interpret Infrared Satellite Pictures?

Clouds and atmospheric gases inclusive of water vapor radiate infrared electricity to area. The amount of energy radiated by clouds and gasses relates directly with its temperature. This relationship, understand as the Stephan-Boltzmann Law, allows us to “see” clouds at night. The atmosphere generally cools with top. A cloud that radiates low strength is higher within the troposphere than a cloud that radiates better power.

On a wellknown linear enhancement curve, vivid white represent cold ice-crystal clouds, while clouds coloured with mild sun shades of grey are warm water filled clouds inside the mid and lower troposphere. There are a number of enhancement curves that coloration pictures of clouds based totally on temperature. These curves accentuate temperature degrees that permit us to determine high clouds from mid and low clouds. At the bottom of every infrared picture there may be a key telling you the temperature variety for that coloration. For instance, on the infrared photographs provided in this internet web site, purple represents cloud tops with a temperature of -40C which in a popular environment is about 40,000 feet.

Q12. What Is A Sector ?

To take a look at the climate situation of a selected region, we can select that place that is referred to as sector. We are interested in the weather of India, so we pick that vicinity.

Q13. Which Products Are Being Derived From Operational Indian Geostationary Meteorological Satellites?

The following merchandise are being derived from INSAT satellites

Outgoing Longwave radiation (OLR)

Sea surface temperature (SST)

Quantitative precipitation estimate (QPE)

Cloud Motion vectors (CMV)

Water Vapour Wind (WVW)

Cloud Top Temperature (CTT)

Visible Channel Image

Infrared Channel Image

Colour Composite Channel Image

Water vapour Channel Image

Q14. Why Are Meteorological Satellites Needed?

Meteorological satellites offer essential records to be used in extra accurate weather forecasts and worldwide weather monitoring.

Q15. What Is The Difference Between Geostationary And Polar Orbiting Satellites?

A geostationary satellite tv for pc is located above the Equator and orbits the Earth on the same rotation speed because the Earth itself, making it appear desk bound from the factor of view of an observer on the Earth’s surface. It flies very high above the floor of the Earth (altitude almost 36000 kilometers), and accordingly is capable of capture the complete Earth disc right now. A polar orbiting satellite tv for pc circles the Earth at a close to-polar inclination, that means that it constantly passes nearly precisely above the poles.

The satellite passes the equator and every latitude at the identical local sun time every day, that means the satellite tv for pc passes overhead at basically the same solar time during all seasons of the 12 months. The low Earth orbit (800 - 850 kilometers) is a whole lot towards Earth than a geostationary orbit, and thus can see a smaller a part of the Earth below than a geostationary satellite, but in finer element.

Q16. What Is Communications Satellite?

A communications satellite tv for pc (on occasion abbreviated to COMSAT) is an synthetic satellite stationed in area for the motive of telecommunications. Modern communications satellites use a selection of orbits together with geostationary orbits, Molniya orbits, other elliptical orbits and low (polar and non-polar) Earth orbits.

Q17. What Is Validation?

In order to check the validity of the satellite measurements, it has to be in comparison in opposition to floor measurements (balloon soundings, lidar measurements, UV measurements and many others.). This technique is called validation.

Q18. Which Satellites Are Being Used To Monitor The Weather Of Indian Region ?

Kalpana-1 placed at Longitude seventy four° E and Insat-3A located at 93.5° E each geostationary satellites are getting used to screen the climate of Indian region.

For meteorological observation, INSAT-3A contains a three channel Very High Resolution Radiometer (VHRR) with 2 km resolution in the seen band and eight km decision in thermal infrared and water vapour bands. In addition, INSAT-3A consists of a Charge Coupled Device (CCD) digital camera which operates inside the seen, close to infra Red and short wave infrared bands presenting a spatial decision of 1 km. A Data Relay Transponder (DRT) running in UHF band is included for real-time hydro meteorological data series from unattended structures placed on land and river basins. The information is then relayed in prolonged C-band to a principal region. Kalpana -1 Satellite has a three- Channel VHRR and DRT similar to INSAT -3A Satellite.

Q19. What Is Gmt Or Utc?

GMT stands for Greenwich Mean Time, now referred to as UTC (Universal Coordinated Time), and is the nearby time at Greenwich-England, that is at 0° longitude. Weather observations, together with satellite tv for pc pics, are recorded in GMT as a way of solving the trouble of looking to use climate information from exclusive time zones.

Q20. How Do I Interpret Water Vapor Imagery?

Water vapor within the mid and upper troposphere absorbs infrared energy at discrete wavelengths. Using this data, water vapor can act like a tracer of atmospheric flow inside the mid and top troposphere. Dark areas on water vapor photographs are typically areas in which the air is sinking and drying. Light colored regions are regions of growing motion and moisture. Water vapor snap shots are useful in locating jet streams and quick-wave troughs and ridges within the mid and top troposphere, however are awful whilst trying to see clouds near the floor together with stratus.

Q21. What Is Anti-satellite tv for pc Weapon?

Anti-satellite tv for pc weapons (ASAT) are area weapons designed to incapacitate or break satellites for strategic military purposes. Currently, only the US, the previous USSR (now Russia) and the People’s Republic of China are recognized to have evolved these guns. On September thirteen, 1985, america destroyed US satellite P78-1 using an ASM-a hundred thirty five ASAT anti-satellite missile and malfunctioning US undercover agent satellite tv for pc USA-193 the usage of a RIM-161 Standard Missile 3 on February 21, two hundred@On January 11, 2007, China destroyed an antique Chinese orbiting weather satellite.

Q22. What Is Special About The Insat 3d Satellite?

It can have  payloads- a 6-channel Imager and a 19 –channel Sounder almost much like GOES satellites of USA. It can even have a Data Relay Transponder (DRT) similar to Kalpana-1 and INSAT-3A.

Unlike previous geostationary meteorological satellites released by India, this satellite will permit programmable scanning of a special quarter, with described N-S and E-W coordinates. Scanning will also be quicker and the data will be at a better resolution as compared to the presently operational satellites. So the geophysical products derived at some point of the scanning may be more accurate and of better decision.

Q23. How Are Water Vapor Satellite Images Used?

Basically, water vapor snap shots and loops/films show how wet or dry the center and higher environment is. They additionally show the air move within the middle and upper environment.

Q24. What Is A Satellite Image?

It is a pictorial illustration measuring the electromagnetic electricity recorded by way of a sensor, now not by pictures. A picture is normally taken within a positive spectral variety (visible light). Satellites take snap shots outdoor this restrained variety.

Q25. Sea Surface Temperature (sst)?

As we understand oceans are the foremost storage of heat inside the earth climate structures. Sea Surface Temperature (SST) is one of the key controllers of climate variability and acts as a big thermal reservoir. SST regulates the switch of lengthy wave radiation to the atmosphere as well as the latent and sensible heat fluxes into the lower environment.

Q26. What Is Miniaturized Satellite?

Miniaturized satellites or small satellites are artificial satellites of strangely low weights and small sizes, normally underneath 500 kg (1100 lb). While all such satellites may be known as small satellites, unique classifications are used to categorize them based on mass.

Q27. Quantitative Precipitation Estimate (qpe)?

It is one of the key meteorological parameter. A specific expertise of its distribution in space and time is important for understanding weather & climate. Information approximately rainfall is of brilliant price in style of discipline beside being manage to human survival scientifically The latent warmth launched throughout the system of condensation water into cloud and rain drops is one of the huge electricity source accountable for atmospheric warmth engine.

Q28. What Is Space Station?

A area station is an synthetic shape designed for humans to stay and work in outer area for a time period.

To date, most effective low earth orbital (LEO) stations had been applied, otherwise known as orbital stations. A space station is prominent from different manned spacecraft via its loss of major propulsion or landing facilities—rather, other motors are used as shipping to and from the station. Current and recent-records area stations are designed for medium-time period dwelling in orbit, for periods of weeks, months, or even years. The simplest area station presently in use is the International Space Station. Previous stations encompass the Almaz and Salyut series, Skylab and Mir.

Q29. What Is Biosatellite?

A biosatellite is a satellite tv for pc designed to carry existence in space.

NASA released three satellites mainly named Biosatellite (1, 2 & three) among 1966 and 1969.

Biosatellites include:

Bion series of satellites

the Mars Gravity Biosatellite.

Orbiting Frog Otolith

Q30. What Is Space Observatory?

A space observatory is any tool in outer area which is used for observation of distant planets, galaxies, and different outer area objects. This category is distinct from other observatories placed in space that are pointed towards the earth for the reason of reconnaissance and different varieties of facts gathering.

Q31. What Are The Types Of Satellite?

Types of Satellite are as underneath:

Anti-Satellite guns/”Killer Satellites”

Astronomical satellites

Biosatellites

Communications satellites

Miniaturized satellites

Navigational satellites

Reconnaissance satellites

Earth observation satellites

Space stations

Tether satellites

Weather satellites

Q32. Outgoing Long Wave Radiation (olr)?

Majority of meteorological sensors perform in lengthy wave range of radiation so that:

They operate day and night time

The hassle of low albedo is not encountered

The earth radiation is most and thermal IR and ocean emissive is nearly unity.

Keeping the above into mind the outgoing flux of lengthy wave radiation at the top of atmosphere is an vital parameter in the earth surroundings radiation finances. This parameter can be derived by way of physical/statistical set of rules from the slim band.

Q33. How Do I Interpret Visible Satellite Pictures?

The snap shots sent returned to us from Weather Satellites are without a doubt images taken from outer space. We get visible snap shots in the course of the daytime while the earth displays daylight lower back to outer area. Visible snap shots display the quantity of mild contemplated returned to outer space. Thick water wealthy clouds, consisting of stratus (commonplace along the North Coast at some stage in Summer months), show up as brilliant white on seen images. Snow p.C. Over the Sierra Nevada during the Winter is any other excellent reflector of sunlight. During the night time, visible pix are absolutely black as there may be little or no or no seen mild to mirror!

Q34. What Is Spy Satellite?

A undercover agent satellite officially referred to as a reconnaissance satellite is an Earth commentary satellite or communications satellite deployed for army or intelligence programs.

These are basically area telescopes which are pointed in the direction of the Earth in place of towards the celebrities. The first technology kind took pictures, then ejected canisters of photographic movie, which might descend to earth.

Q35. What Is Global Navigation Satellite System?

Global Navigation Satellite Systems (GNSS) is the standard frequent term for satellite tv for pc navigation structures (“sat nav”) that provide independent geo-spatial positioning with worldwide coverage. GNSS allows small digital receivers to decide their region (longitude, latitude, and altitude) to within some metres the usage of time alerts transmitted alongside a line-of-sight through radio from satellites. Receivers calculate the best time in addition to position, which can be used as a reference for scientific experiments.

Q36. How The Cmvs Generated?

In general, there are five steps inside the derivation of Cloud Motion Vectors :

Registration of Triplet

Cloud Tracers selection

Tracking of Cloud Tracer within the Target picture

CMV Computation

Height Assignment

Quality Control of Cloud Motion Vectors.

INSAT-based CMVs are specifically useful inside the evaluation of higher winds all through the monsoon season to look at the formation of eddies, move –equatorial waft, approach of the 2 separate branches of the monsoon.

Three levels of the INSAT CMV are:

Low Level CMV – one thousand hpa – seven hundred hpa.

Medium Level CMV – seven-hundred hpa – three hundred hpa

High Level CMV – 300 hpa and above.

Q37. What Do Ir And Vis Mean? What Do We See On Ir And Vis Images?

IR stands for infrared. On an photograph, IR is usually accompanied by a wavelength in micrometers (e.G. 10.7). In the IR spectrum, clouds at exceptional heights show up thoroughly as differences in radiances (amount of mild power detected) from ground stage (radiances range with cloud peak). Radiances can then be converted into temperatures with a few calculation. So what we see on an IR photograph is the distribution of temperatures as detected by way of the satellite's sensor, and the temperature in the legend corresponds to the temperature of regardless of the satellite tv for pc sensor "sees" (clouds at distinctive heights, sea surface, and earth floor).

VIS stands for visible. A VIS satellite photograph (taken inside the seen spectrum) is a picture of the earth from space, simply as you would see it in case you have been searching out the window from a spacecraft in orbit. During nighttime the picture is dark.

Q38. Why Are Some Images Missing?

There are times when there are system faults in our machine, but a more likely clarification is the hassle in reception or dissemination of the image. The problems in reception encompass, an artifact impact in the pictures, patch temperature variation, or satellite renovation troubles. However, these are exceptionally rare.

Q39. Geostationary Orbit ?

Satellite in a circular orbit approximately 36000 km above the equator move in time with earth. Satellites on this orbit are called geostationary due to the fact they're stationary with recognize to the earth and appear like constant in sky.

Q40. What Is Satellite Meteorology ?

Satellite Meteorology refers to the look at of earth's surroundings and oceans using facts acquired from faraway sensing gadgets flown onboard satellites orbiting the earth. Satellite make measurements in a roundabout way by using sensing electromagnetic radiations coming from the surfaces under.

Q41. What Are The Advantages / Disadvantages Of Geostationary Satellites For Remote Imaging?

As they are located at any such excessive altitude the spatial resolution (i.E. Amount of element shown) of their pix (generally 2.5 Km in step with pixel) has a tendency to be no longer as accurate as some polar orbiting satellites (typically 1 Km to 50m according to pixel), which might be lots towards the earth.

However the benefit of their brilliant peak is that they can view the whole earth disk underneath them, as opposed to a small subsection, and they can scan the equal vicinity very regularly (normally each half-hour). This makes them best for meteorological programs.

One huge hassle with Geostationary satellites is that seeing that they're always positioned above the equator they cannot see the north or south poles and are of restrained use for latitudes more than 60-70 levels north or south. The further from the equator the decrease the spatial resolution of every pixel and the more the opportunity of being hidden via the earth's curvature.