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FAQs
Propellants
- What are propellants? Discuss various types of propellants.
- What are solid propellants? List its disadvantages.
- What is perforation?
- How are the solid propellants classified?
- Name the two important components of the propellant
- What are the advantages of liquid propellants over solid propellants?
- List the different techniques by which petroleum fuels are manufactured.
- How are the liquid propellants usually classified?Ans.: They are usually classified as: a) Monoliquid Propellants – In their propellants, only one chemical act as fuel as well as oxidizer. Eg: Hydrazine, Nitromethane. b) Biliquid Propellants – In this propellant, there is liquid fuel and liquid oxidizer. Eg: Liquid Hydrogen and liquid oxygen.
- Give the classification of liquid propellant on the basis of origin.
- What parameter decides the behavior of propellant? Ans.: Specific impulse. Higher the specific impulse better is the propellant.
- What are cryogenic propellants? State their advantages.
- What are hypergolic propellants?
- “Hypergolic propellants lead to burden on manned spacecraft”. Comment. Ans: Hypergolic propellants are very poisonous. They react with wing tissues and cause injuries. Hence, it is mandatory for technicians to wear full-body self-contained atmospheric protection ensemble suits. Thus, the comment is justified.
- How is the fuel used in space vehicles different from the household fuel?
Propulsion
- What are the two main laws of rocket propulsion?
- Why are the space agencies developing new propulsion techniques?
- What is the main source of energy for nuclear propulsion? Ans.: Nuclear propulsion uses nuclear reactions – Nuclear fusion • Nuclear fusion. Both these reactions liberate lot of energy because of mass defect. So, mass defect and mass energy equivalent relation are 2 main reasons for high energy is nuclear propulsion.
- Why fission propulsion technique is preferred over fusion propulsion technique? Ans.: Fission propulsion technique uses fission process whereas fusion propulsion uses fusion process. Fission occurs at room temperature but fusion requires very high temp. (Approx. 10 6 K), which is practically hard to implement is spacecraft. Thus, fission is preferred over fusion though energy is fusion is more as compared to fission.
- List the different types of electric propulsion techniques.
- What is the principle of electric propulsion?
- What is the principle of electromagnetic propulsion?
- How do laser differ from ordinary while light? Ans.: Lasers are monochromatic, coherent, intense beam of light consisting of only one wavelength where as white light is diffused and consists of many wavelengths
- Why antimatter spacecraft are not practically implemented? Ans.: Antimatter spacecraft are not practically implemented due to the lack of antimatter particles existing in the universe . Hence, it is very hard to implement this propulsion technique.
- What is conventional method of propulsion?
- What is the principle behind microwave propulsion?
- What are air-breathing rockets?
Space Shuttle
- What is spacecraft?
- What are the main parts of space shuttle? Ans.: Space shuttle consists mainly of 3 parts: (i) Orbiter Tank (ii) Solid Rocket Boosters (iii) Main propulsion systems (iv) Space shuttle main engine
- What is fuel cell? How does it differ from normal cell? Ans.: Fuel cell and normal cell both converts chemical energy to electrical energy but the by-products of fuel cell be used for various purposes while for normal cell, by products can not be used. Eg: of fuel cell is H2-O2 cell, which gives water as product, which can be used for human consumption. Thus, it not only acts as electric source but also act as source of clean water.
- What is meant by sub-system of spacecraft? Ans.: Before designing any spacecraft, it is desired to make a brief sketch of aircraft, it's components and their function, circuits to perform the intended function of spacecraft, it's protection etc. All these points are taken into consideration and various blocks are made to fulfill those consideration called as sub-system of a spacecraft.
- What are solar cells? It is a photovoltaic cell that converts solar energy into electricity. A photovoltaic cell consists of semiconductor layers as shown below: When light falls on the cell, a part of it is absorbed which knocks electrons and allows them to flow freely. Photovoltaic cells have electric field, which force the electrons to flow in a specified direction. This flow of electron is current, which can be drawn for external use. Anti reflecting coating is applied so that sunlight will not be reflected. Glass cover plate protects the cell.
- What are the different sub-systems of a space shuttle?
- State the significance of attitude & articulation control of spacecraft?
- What are rocket boosters?
- What are the three dimensions / sub-tasks of data handling?
- Name the part of the space shuttle which returns to earth.Ans: Orbiter is the only part of the shuttle, which returns to the earth. For more details see orbiter
- How does space shuttle generate power for its operations?
- How is the data collected by space shuttle telemetered to earth?
- How is the external fuel tank protected from aerodynamic and friction heating?
- List the main parts of orbiter
- In which part of the orbiter do astronauts stay? Ans: crew compartment. For more details see orbiter
- How many rocket boosters is the space shuttle equipped with? Ans: a space shuttle is equipped with two rocket boosters to provide thrust. For more details see solid rocket boosters.
- Which component of space shuttle supports the entire weight of the orbiter and fuel tank on the launch pad? Ans: Solid rocket booster. For more details see Solid rocket boosters.
- What are the stages of launching of a shuttle
- In which stage is the rocket booster jettisoned? A The rocket booster is jettisoned at the end of the first stage of launch. For more details see ascent.
- List the major events that take place during the second stage of launch.
- In case of an emergency what are the different abort modes that a shuttle follows?
- What are the different types of intact aborts and how do they differ from each other?
- What is a contingency abort? When is this mode adopted?
- List the main operations during orbital insertion
- What is meant by shuttle deorbiting?
- What is meant by the term “retro fire”? Ans. The spacecraft spins 180 0 and the thrusters fire to reduce the speed by 200mph. This process is termed as “retrofire”.
- What are the demerits of vertical landing?
- What is “ ionization blackout”? Ans. The hot ionized gases present in the atmosphere prevent radio communication with earth for about 12 minutes. This is referred to as “ ionization blackout”.
Types of spacecraft
- Why are atmospheric spacecrafts equipped with aeroshell?
- List the different types of spacecraft classified on the basis of their application
- What is the main function of communication spacecraft?
- What is meant by the term “Solar occultation”? Ans. Occultation is blockage of light due to intervention of another object. Thus solar occultation is blockage of sun's rays. During this period spacecraft is powered with the help of batteries.
- Why must penetrator spacecrafts have sturdy construction?
- What are fly by spacecraft?
- What is the main function of rover spacecraft?
Space station
- Why should space stations be built with the help of lightweight materials? Ans. Lightweight materials must be used for the construction of space station to reduce the transportation cost. Currently it takes $10,000 per pound to launch an object into space. Thus with the help of lightweight materials the launching cost can be reduced.
- How do space stations generate power for their operation?
- How is the movement between the space station and outer space enabled? Ans. To reach outside of the space station air locks are used. It is a chamber consisting of 2 airtight sealed doors one of which leads to outside empty space and the other to the inside of the space station.
- What are the various applications of space station?
- How is the air supply and heat regulated in the space station?
- Why is Space station designed with milk white colored or frosted windows? Ans. A milk white coloring or frosting of the window ensures that all the harmful radiations are filtered.
- Name the first space station. Which country launched it? Ans: The first space station was "Salyut" launched by Russia in 1981. for more details see salyut.
- Name the space station, which was launched by USA Ans: Space station Skylab was launched by Russia . For more details see Skylab.
- What were the objectives of MIR space station launched by Russia ?
- Which countries are participating in International space station (ISS) project? Ans: The International Space Station is a huge collaborative effort between 16 nations, including the United States , Canada , Japan , Russia and 11 participating member nations of the European Space Agency -- Belgium , Denmark , France , Germany , Italy , the Netherlands , Norway , Spain , Sweden , Switzerland and the United Kingdom . In addition, Brazil and Italy have signed on as payload participants.
- What are the various components of the ISS?
- Which was the first component of ISS to be launched? Ans.The first component to be launched was the Russian zarya module.
- What is the expected lifetime of ISS? Ans. The expected life of ISS is 10 years.
- How is space station waste disposed? Ans. Non-recyclable items are put on either a return vehicle, which will totally disintegrate re-entering Earth's atmosphere, or on one of the shuttles, which brings it all the way back to Earth for disposal.
- How has the ISS helped in research in the field of earth science?
- Why are the different modules of space station designed separately and assembled in space? Ans.The space station is constructed in separate modules, so that these components can be easily transported into space. The modules are then reassembled to form the space station.
- How does the experiment conducted by ISS on life science give an insight into the aging process?
Mission to mars
- Is MER sent to mars to detect martian life?
- What is the duration of the MER mission? Ans. The twin rovers, spirit and opportunity are expected to telemeter data to earth for atleast 90 martian “sols” (days). The deposition of dust on solar arrays could however alter the duration of the operation.
- How did the MER came to be named as “spirit” and “opportunity”? Ans. Nasa had conducted an essay contest to name these rovers. The contest winner sofi collis gave the name ‘spirit” and “opportunity” to the rovers.
- Why did NASA built both the rovers having same design? Ans. Both the rovers were designed identical to give many practical advantages. If there were 2 different designs for the rovers then the performance test would have to be carried out twice. Thus having identical design saved a lot of time.
- How is the information sent to earth during the entry, descent and landing stages?
- What are the various instruments the rover is equipped with?
- What is the landing site of these rovers? Ans. Spirit landed on mars on January 3 near the center of Gusev crater. Gusev crater is predicted to have been a lake. Opportunity landed on January 24 near Meridiani Planum. This region contains deposition of a mineral formed in presence of water.
- What is the reason that will lead to the disfunctioning of the rover? Ans. Rovers are equipped with solar panels capable of providing 140 watts of power for 4 hours per day. But due to the deposition of dust on solar panel, weaker sunlight due to seasonal change and low battery, the rover will be capable of generating only 50watts of power. This power will not be sufficient for the rover to carry out its operation.
- What were the reasons that led the scientist to believe that life existed on Mars?
- What are probes? List their functions.
- How are probes classified?
- Why were different launch vehicles used for launching of “spirit” and “opportunity”?
- List the various stages of the launching of the MER
- What is a payload fairing?
- What is the function of strap-on rockets?
- Which stage provides the rovers velocity to escape earth's gravitational pull?
- What are the major activities of the cruise stage?
- What is a “sol”? Ans: A “sol” is a Martian day. It is 40 minutes longer than the earth day.
- Discuss the methods, which are used to keep the rover warm.
- What are radioisotope heater units?
- What are the different parts of the cruise stage configuration?
- How do star scanners and sun sensor help in determining the position of the rovers?
- List the different equipments carried by the landing system
- How do aero shells protect the system during landing?
- List the parts of aero shell
- Why is nylon and polyester used for making parachutes?
- How do the airbags protect the lander during landing?
- What is the function of lander?
- Describe the procedure of the landing of rover
- List the main parts of the rover body
- How is the health of the rover monitored?
- How does aerogel help in maintaining the temperature of the rover body?
- What are different instruments mounted on the rover's arm?
- How does the rover communicate with earth?
- How many wheels does MER have?
- What is deep space network?
- What are the instruments used by the rover to communicate with earth during the cruise phase?
- Why are manned missions not sent to mars?
Mission to moon
- Name the first manned mission to moon. Who were the crewmembers?
- List the parts of Apollo-11 spacecraft
- What is a lunar module?
- Name the various rockets that make of the launch escape system.
- Where on the surface of moon did the lunar module land?
- Name the experiments performed by the spacecraft
- Which experiment helped in determining the distance between the earth and moon?
- What are the different minerals present in layers of moon?
- How was the solar wind composition experiment performed?
Mission to Venus
- Venera missions
- Which country launched the venera spacecraft? Ans. Russia . For more information see Venera missions
- Name the 2 main parts of venera spacecraft. Ans. Orbiter and lander. For more information regarding their working see orbiter and lander.
- What are the different instruments carried by the orbiter?
- Magellan spacecraft
- What are the different parts of Magellan spacecraft?
- How was the data transferred to the earth by the Magellan spacecraft?
- Name the subsystems incorporated into the Magellan spacecraft
- Despite having less fuel, how were the repetitive altitude changes accomplished? Ans. T he repetitive attitude changes were accomplished with reaction wheels that used Newton 's Third Law. When it was desired to turn Magellan in a particular direction, an electric motor inside the spacecraft was commanded to spin a reaction wheel in the opposite direction. By Newton 's Third Law, the spacecraft turns in the intended direction while the reaction wheel spins in the opposite direction.
- Which instruments were employed for keeping a track of the spacecraft's current orientation? Ans. Gyroscopes and star scanners. For more information see Magellan-altitude control
- What is the function of command and data handling system?
- How was the temperature of the Magellan spacecraft regulated?
Mission to other planets
- Cassini –huygens spacecraft
- Name the three space agencies which built the cassini-huygens spacecraft.
- What is the main aim of launching this spacecraft? Ans. The mission of this spacecraft is to orbit Saturn and its moons and study the atmosphere of the moons.
- What is the function of the various instruments carried by cassini?
- What is the function of spectral spectrometer carried by the huygen's probe?
- Jupiter icy moon orbiter
- What is the aim of this mission?
- When is this mission proposed to be launched?
- What is the major challenge faced by this spacecraft
- Which propulsion technique will be used to propel the spacecraft?
- Terrestrial path finder
- What is aim of this mission?
- What are the technologies proposed to be used by this spacecraft?
- Voyager
- What is the aim of the extended mission of voyager 1 and 2?
- What are the three phases in which mission is classified?
- What are the main parts of the spacecraft?
- List the various instruments integrated into the spacecraft
- What is the main function of altitude and articulation control system?
Space travel
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