Sissejuhatus kosmonautikasse (Introduction to Astronautics), YFT0060

Revision questions

Note: questions are given for revision of the corresponding material only. These are not examination questions. You need not to be able to answer each question nor give absolutely exact answers. However, it is nice if you have general idea about the issue and you are able to give an answer to most of these questions.

1. Main goals and methods of Astronautics. Ways to space
   • Main areas where achievements of Astronautics are used
   • Role of global navigation and positioning.
   • Which scientific researches are possible only in space and why?
   • How did the first communication satellite Echo 1A look like? What it was?
   • When was the first active communication satellite launched? (Approximately, you do not need to remember exact years, "mid 1960th is enough".)
   • When was the first geostationary satellite launched?
   • What global navigation and positioning systems do you know?
   • What was the Tiros I?
   • Why weather satellites are placed mostly into polar orbits?
   • What has the first US satellite discovered?
   • What space telescopes do you know? What types of space telescopes exist?
   • Why Hubble space telescope is so famous?
   • What advantages do space telescope have?
   • What were the Luna-3, Luna-9, Luna-16, Luna-17?
   • What was the Mariner 10?
   • What spacecraft first sent close-by photos of the Jupiter and the Saturn? Of the Uranus and the Neptune? When?
   • What space probes made the most important contributions to our knowledge about the Mars?
   • What space probes made the most important contributions to our knowledge about the Venus?
   • What were the Vega space probes? What was the Magellan?
   • What was the Galileo? What is the Cassini/Huygens?
   • What large bodies of the Solar System remain unvisited by space probes? Do you know when they will be visited?
   • What alternatives to rockets as launch vehicles do you know?
   • What advantages do space gun and mass driver have?
   • What problems do space gun and mass driver have? Where these problems may be reduced?
   • What is the idea of space planes? What problems are connected with them?
   • What projects of space planes do you know?
   • What is ramjet/scramjet? What are their advantages and problems?
   • How does space elevator work? What other ways to use tethers do you know?
   • What was the first space rocket?
   • What were the biggest space rockets?
   • What is the Sea Launch? What is the Pegasus?
2. History of Astronautics
   • What did Architas demonstrated?
   • What were fire arrows? What was hwacha?
   • Who's works have given first theoretical explanations to the rocket motion? When they appeared?
   • What were the Congrave rockets? What was their improvement compared to earlier fire arrows?
   • How could Hale remove the guiding rod?
   • What applications of rockets in 19th century do you know?
   • What were Tsiolkovsky's most important contributions?
   • Why Goddard is considered one of the fathers of the modern Astronautics?
   • What are advantages of liquid-fueled rocket engines compared to solid rocket motors?
   • Who was the leader of practical rocket engineering in Germany in 1930th?
   • Who's contribution to the rocket technique is the most important? In Germany? In USSR?
   • What was V-1?
   • What was V-2? How large was it? How was it steered? Why is it so famous? Was it effective weapon?
   • What was Penemünde? Mittelwerk?
   • How did Americans and Soviets use the German rocket legacy?
   • Why the USSR concentrated its efforts in ICBMs and US did not?
   • Why ICBMs are not effective with conventional warheads?
   • What is the R-7 "Semyorka"? Why it is so famous? What is its importance for the history of Astronautics?
   • What can you tell about the construction of R-7? How many stages does it have? Why steering engines were used instead of gas vanes? What was its launch weight and range?
   • What is the role of the International Geophysical Year in the history of Astronautics?
   • What was the reason to launch the Soviet "Object D"? The first Soviet satellite?
   • When was the first satellite launched? What was it (shape, weight, construction)?
   • Why von Brauns' opportunities in US were limited?
   • What was the Redstone rocket? The Jupiter-C? The Juno?
   • What was the project Vanguard? When was the first US satellite launched?
   • Who was Laika? What were the Luna-1, Luna-2, Luna-3?
   • When was the first man launched to space? What is the name of this man?
   • What was the first American crewed spacecraft?
   • What were the Telstar 1, Tiros 1, Syncom 2 & 3?
   • What were the Voskhod spacecraft? What was done at its launches? Who is Aleksey Leonov?
   • What were the Rangers? What was the Luna-9? The Luna-10? What were the Surveyors?
   • What was the Moon Race? What was it motivated with?
   • When did the first docking in space occurred? What was the Gemini spacecraft, what new functionality did it have?
   • What was the Saturn rocket family? What was the Saturn V? How large was it?
   • What crewed spacecraft was the first to orbit the Moon? When? When were the first men walked on the Moon? What are their names?
   • What was the N1? What were the Zonds?
   • What was the Luna 16? What were the Lunokhodes? How did these space probes look like?
   • What was the first space station? What was the first US space station, how was it built?
   • What are the most significant achievements of Venera space probes?
   • What were the Vikings? What were the Pioneers 10/11? What was the Mariner 10?
   • What was the Salyut-6?
   • What is the Space Shuttle? When was it launched for the first time? What happened to the Challenger & the Columbia?
   • What was Mir space station? What was Energia launch vehicle? The Buran spacecraft?
   • What were the Voyagers, why are they so famous? What was the Galileo? The Magellan?
   • What is the Hubble space telescope?
   • What latest Martian space probes do you know? What was the first successful Mars rover?
   • What is the International Space Station? Who are the principle participants of this project?
   • What is the Cassini? The New Horizons?
   • What were the first three members of the Space Club?
   • What other members of the Space Club can you mention?
   • What can you tell about efforts of China in space?
   • What other countries may enter the Space Club soon?
3. Basics of orbital mechanics
   • Put down Newton's law of gravity and centripetal acceleration.
   • What is gravitational parameter?
   • Deduce the formula for circular velocity and the orbital period for a circular orbit.
   • What are the circular velocity and the period for the Earth's zero-altitude orbit?
   • What is the escape velocity? Deduce the formula for it. How is it related to the circular velocity?
   • What is the velocity at an elliptical orbit? Put down the equation of ellipse in polar coordinates.
   • What are apsides, periapsis, apoapsis, semi-major axis, eccentricity, true anomaly?
   • Formulate Kepler's Third law and the Kepler's Equation. What are mean anomaly and eccentric anomaly?
   • Deduce the height of apoapsis and apoapsis velocity from the height of the periapsis and periapsis velocity.
   • What is vis viva equation? What is the total energy of spacecraft on an elliptical orbit?
   • What is hyperbolic velocity? What is hyperbolic excess?
   • What types of orbits exist in central gravity field? How are they related to conic sections? What are real orbits of satellites?
   • What is specific energy of a spacecraft? What specific energy should be provided to put a spacecraft to a circular orbit?
   • What is ideal velocity of a rocket?
   • What is mission characteristic velocity? What is the characteristic velocity for sending a spacecraft to a low circular orbit?
   • How does mission characteristic velocity depends on mission planning? What is the Oberth's effect?
   • Why mission characteristic velocity is crucial for mission planning?
   • Why each ~2.5 km/sec doubles the weight of the rocket or spacecraft? Why actual launch vehicles put only ~4 % of their launch mass to LEO as payload?
   • How do launch losses (gravity drag, atmospheric drag etc.) influence characteristic velocities of launch vehicles? What is the role of the Earth's rotation?
   • Compute the characteristic velocity for a mission where a spacecraft leaves the Solar system.
   • Compute the characteristic velocity for a Moon soft-landing.
   • Why a Moon soft-landing mission needs a higher characteristic velocity than a Mars soft-landing?
   • Why a direct fall to the Sun needs so high characteristic velocity?
4. Orbital elements & types of orbits
   • What are the Keplerian elements and what is the meaning of each of them?
   • What other elements are in use?
   • What elements are used for solar satellites?
   • Describe the circular equatorial orbit. What is its ground track?
   • What is the ground track of circular orbits with intermediate inclination?
   • What is geosynchronous orbit? How may its ground track look like?
   • What is Molniya orbit? What defines its inclination?
   • What causes nodes regression?
   • Why polar orbits are useful?
   • What are Sun-synchronous orbits? How are they provided? How are they used?
   • Why the latitude of the launch site is so important? What latitudes have most advantages?
   • What is the idea of the Sea Launch?
   • How the number of launch windows is related to the latitude of the launch site and the inclination of the target orbit?
   • What are Low Earth Orbits? What are their advantages?
   • Why most of manned missions are sent to LEO?
   • How is it possible to organize communications through LEO satellites?
   • What are Medium Earth Orbits? Which satellites use them? Why MEO may be problematic?
   • What is Geostationary Orbit? Why are they so suitable for communication satellites?
   • Why GSO satellites have to spend delta-v of ~50 m/s per year? What is Graveyard Orbit?
   • What are the basic disadvantages of GSO?
   • What is Geostationary Transfer Orbit? Why launch vehicles usually do not carry their payload to GSO?
   • What are High Earth Orbit and Highly Elliptical Orbit?
   • What are Escape Orbit? Hyperbolic Orbit? Capture Orbit? Heliocentric Orbit?
   • What are Lagrangian points? Which of them are stable and which are unstable? What does their (in)stability mean? What are Halo orbits?
5. Orbital perturbations
   • How do real satellites move? How their motion is analyzed in celestial mechanics?
   • What are orbital perturbations? What are secular and periodic perturbations?
   • What is the cause of atmospheric drag? How does it depend on the orbital height and why? Why are long-term predictions of this perturbation not very precise?
   • How do the formulae of the drag force & acceleration look like? What is ballistic coefficient? How it depends on size of the object?
   • What are typical BC values and drag acceleration values on orbits of different heights?
   • Estimate annual delta-v needed to maintain the orbital height. What is the minimal height at which a satellite may stay at least one revolution?
   • Estimate altitude change per one revolution caused by drag. How do the period and the velocity change?
   • What is the satellite paradox? What is its explanation?
   • How is it possible to give a rough estimate of the lifetime?
   • How do lateral forces influence the orbit? What is their cause?
   • How does drag influence the eccentricity and why? How is it possible to estimate the eccentricity change per revolution?
   • What are the main factors influencing the atmospheric conditions from the point of view of drag force?
   • How is uneven shape of the Earth considered in celestial mechanics? What are spherical harmonics? Zonal harmonics? Sectorial & tesseral harmonics? What do they account for?
   • Why J2 is so important, what does it account for?
   • What are the main results of perturbations from J2?
   • How does regression of nodes depend on the inclination? Why is it zero for polar orbits? How is it used for Sun-synchronous orbits?
   • What is the result of rotation of apsides? How can it be avoided?
   • When is resonance with the Earth's rotation possible?
   • Why do stable and unstable points exist for GSO satellites? What is libration?
   • How does the Moon and the Sun influence the orbits? For which orbital heights their influence is important? What perturbs satellites more, the Sun or the Moon?
   • What is the influence of lunisolar perturbations on circular orbits? What elliptical orbits are sensitive to these perturbations? What happens if the apogee is very high?
   • What is the general formula for Solar Radiation Pressure? What is the solar constant? How is radiation absorbed and reflected?
   • How do SRP perturbations depend on the size of the satellite? On the orbital height? On the attitude and reflectance of the satellite?
   • At what height is the SRP role comparable with the role of drag? Where is it higher and where is lower?
   • How does SRP change orbital eccentricity?
   • What is solar sail? How can SRP be used?
   • What is the role of the Earth's albedo, when may it be important? Why magnetic fields may influence the motion of a satellite?
   • What is the role of General Relativity effects in the satellites motion? What is residual exhaust?
6. Orbital maneuvers
   • What are the standard assumptions of astrodynamics? How are they fulfilled in reality?
   • What basic rules are fulfilled if the standard assumptions are taken?
   • Why if only one burn is performed, the spacecraft will return to the point of this burn?
   • What is delta-v, why this characteristic is so important for space maneuvers?
   • What is the Oberth's effect, how can it be explained physically?
   • Why horizontal thrust application is generally desirable?
   • Why the thrust should be applied tangentially?
   • Derive the formula for the delta-v of a plane-change maneuver.
   • Why mission planners try to avoid plane change maneuvers?
   • Why it is better to perform inclination change maneuvers in the apoapsis?
   • What are bi-parabolic and bi-elliptic transfers? How they may be applied to inclination change? When are such maneuvers reasonable?
   • How is it possible to use the Moon for plane changes?
   • What is the Ulisses? What was the role of the Jupiter in its mission?
   • What are Hohmann transfers? Why are they so important? What is their main disadvantage?
   • What is one-tangent burn, when are they used?
   • What is the peculiarity of maneuvers performed with electric propulsion? Is their delta-v larger or smaller than that of the Hohmann transfer?
   • Why bi-elliptic transfers are not a good alternative to Hohmann transfers?
   • What are multiple burn transfers? What are they used for?
   • What is the parking orbit and when it may be useful? Why?
   • To what complications leads the decision to use a parking orbit?
   • What is aerocapture? When it may be used?
   • What is aerobraking? Has it been ever used in practice? When and why?
   • What is rendezvous?
   • What are the roles of the target and of the interceptor in a rendezvous?
   • Why launch windows are short for rendezvous? Why rendezvous are rarely performed on the very first orbit?
   • What is phasing orbit? What is it used for? How may it look like in the cases of the leading target or the leading interceptor?
   • How is final approximation performed? What are the advantages and disadvantages of the direct pointing method and the free trajectories method?
   • When did the first international rendezvous in space happen?
7. Lunar & planetary missions
   • What is the patched conics method? What simplifications does it include?
   • What is the sphere of influence of a celestial body?
   • Why does not the Moon escape to a solar orbit, being accelerated by the Sun more than by the Earth?
   • Why the sphere of influence of the Neptune is larger than that of the Jupiter?
   • From which latitudes it is possible to launch a probe to the Moon with the angular distance of 180 deg? Why?
   • What circumstances should be taken into account to perform a direct launch to the Moon?
   • Why parking orbits are useful for lunar launches?
   • What is the role of the eccentricity of the lunar orbit for lunar missions?
   • What circumstances should be taken into account when choosing the duration of for a lunar transfer?
   • How launch errors influence the trajectory and what is the tolerance of transfer orbits to different errors? How can they be corrected?
   • What is the effective radius of a planet? On what factors does it depend?
   • How does the Moon change the trajectory of a probe that entered its sphere of influence?
   • What is the Ulisses? What was the role of the Jupiter in its mission? Why the leading hemisphere of the Moon is more accessible than the trailing hemisphere?
   • What are the requirements if the probe should be put into a lunar orbit?
   • How is it possible to return from the Moon to the Earth?
   • From what parts does an interplanetary transfer trajectory consist from the point of view of the patched conics method?
   • What is the circle of orbital launches and the circle of direct launches? Is it possible to perform a direct launch to any direction from any latitude (taking into account efficiency considerations)?
   • How the velocity required for an interplanetary transfer may be calculated? What are advantages and disadvantages of Hohmann transfers?
   • What is the configuration angle? What is it for the inner and for the outer planets? How frequently does the launch opportunity occur? What is the synodic month?
   • What problems should be solved to elaborate the optimal strategy of orbital corrections?
   • What possibilities does the electric propulsion offer for interplanetary flights?
   • What is the impact parameter? How can aerobraking and aerocapture be used to save propellant?
   • How does a fly-by trajectory look like in planetocentric coordinates? What is the deflection angle? Why does it have a minimum value?
   • What is the change of the probe planetocentric and heliocentric velocity during a fly-by? What is the maximum change? What deflection angle does it correspond to?
   • What is the gravity assist? How can it be used for interplanetary missions? What was the first probe that used it in an interplanetary mission? Why is this maneuver so common today? What are its disadvantages?
   • How was used the gravity assist by space probes?
   • What is the active gravity slingshot? What is the essence of the aerogravity assist? Why aerogravity assist have not been applied so far?
8. Basics of the rocket propulsion
   • What is the effective exhaust velocity? Why it is not equal to the real exhaust velocity?
   • Derive the ideal rocket equation from the considerations of the law of momentum conservation.
   • What is the mass ratio? What is its role in the ideal rocket equation?
   • Why characteristic velocity is so critical in mission planning?
   • Why missions with high characteristic velocities are non achievable with a one-stage rocket?
   • What are the mass fraction, the payload ratio and the structure coefficient? What are the typical values of the structure coefficient?
   • What characteristic velocities are achievable with a one-stage rocket? How does the multi-stage design help to achieve higher velocities?
   • What elements may be discarded in flight? What are additional advantages of jettison of these elements?
   • Why rise of the number of stages to high values does not help to achieve even higher characteristic velocities? What is the role of cost and reliability?
   • Why lunar landers perform soft landings in one stage? What is the optimum number of stages to send a probe from the Martian surface to the Earth?
   • On what factors does the optimum number of stages depend for launching a satellite to LEO?
   • What a strap-on boosters? How should be calculated the characteristic velocity of a launch vehicle with serial staging? With parallel staging?
   • o What is the optimum distribution of characteristic velocities between the stages of a rocket having identical escape velocities and the structure coefficients on all stages?
   • What is the optimization criterion for real rockets? What are the advantages of rocket families? Is each member of the family weight- or cost-optimized?
   • What factors define the thrust of a rocket engine? How does the thrust change when a rocket ascends in the atmosphere? What is the vacuum thrust?
   • What is the specific impulse? How is it related to the effective exhaust velocity? What is the relation between the mass flow rate, the specific impulse and the thrust?
   • What are the typical values of the specific impulse of common chemical propellants? What are the problems of the CH₄ and F? Of nuclear propulsion?
   • What are the principle factors on which specific impulse depends? Why oxidizer to fuel ratio is often not stoichiometric?
   • What is the role of the propellant density? Why denser propellants are more desirable?
   • What are the most pronounced advantages of solid propellants?
   • When is the thrust important? Why? What is the thrust-to-weight ratio?
   • Why high thrust-to-weight ratio may be problematic? What problems may be related with it?
   • What is g-force? How is it related with the thrust? When it becomes especially critical for a launch vehicle? How the problem may be overcome?
   • How are drag losses at launch related with the thrust? What is the possible solution of the problem?
   • What are typical thrust-to-weight ratios for launch vehicles? What exceptions exist and how are they explained?
   • What sets values of the thrust-to-weight ratio for space probes? How does choice of engine depend on the required maneuvers?
   • What are special demands to the thrust of lunar soft-landing missions? How are they met?
9. Liquid propellant rocket engines
   • What are advantages and disadvantages of liquid propellant engines? What are basic elements of a LRE?
   • What are monopropellants? What are their advantages and drawbacks? What monopropellants do you know, where and why are they used?
   • What are bipropellants? What are their advantages and drawbacks?
   • What are hypergolic propellants? What are cryogenic propellants? What propellant mixtures do you know?
   • Why LOX/LH2 is rarely used on the first stages?
   • How are pressure-fed engines built? What are their advantages and drawbacks?
   • What are pump-fed engines? Why are they most common? What are their drawbacks?
   • What is gas generator cycle? Staged combustion cycle? Expander cycle? What is characteristic for each of these cycles?
   • What are the main parts of a LRE?
   • How cooling of the thrust chamber and the nozzle is organized? What cooling methods exist?
   • What is the working principle of the cooling jacket? Of film cooling? What is tubular wall?
   • Why combustion stability highly depends on the injector? What types of combustion instabilities exist? What is characteristic for these instabilities?
   • Why throttling of an LRE may cause problems, what problems these are, how are they solved in practice?
   • What operations are performed to start an LRE? To cut off an LRE?
   • What is underexpansion, overexpansion, ideal expansion? What are the conditions for nozzles of first stages, of upper stages? Why extendable nozzles are applied?
   • What is de Laval nozzle? What is throat of nozzle? How specific impulse depends on molar mass? On chamber temperature? On chamber pressure?
10. Solid and hybrid rocket motors
    • What are advantages and disadvantages of solid propellant motors? What are basic elements of a SRM?
    • What propellants are used for SRMs? What requirements should it fulfill?
    • Which is the importance of propellant regression rate? How should it depend on pressure and why?
    • How is it possible to set the thrust profile? How different thrust profiles may be organized? Why star-shaped bores are common?
    • Is it possible to change thrust profile in flight? Why standardization of SRM boosters is so important?
    • What is erosive burning? What are slivers?
    • What instabilities are present in burning of a SRM and how is it possible to dampen them?
    • How thermal protection of the nozzle is organized?
    • How SRMs are ignited? How are they cut off? Is it possible to restart a SRM, what problems exist with restart?
    • What constructions of SRM nozzles are the most common?
    • What are advantages and disadvantages of hybrid motors? What are basic elements of a hybrid motor?
    • What propellants are used for hybrid motors? Why problems with the mixture ratio arise?
    • Compare hybrid motors with LREs on one hand and hybrid motors with SRMs on the other hand.
11. Non-chemical propulsion methods
    • What kinds of nuclear propulsion do you know?
    • What is nuclear thermal propulsion? What common does it have with chemical propulsion and what are the differences?
    • What limits the specific impulse when thermal propulsion is used? What types of cores are possible and what specific impulses are achievable?
    • What are the main drawbacks of thermal propulsion? What practical developments do you know from the history?
    • What is pulse propulsion? How it works? What are its advantages and drawbacks?
    • How does radioisotope propulsion works?
    • How does electric propulsion works? What is its advantages and disadvantages? What methods of electric propulsion do you know?
    • How do electrothermal methods work?
    • How do electrostatic methods work? What are the main components of an ion thruster? What propellant is most common and why?
    • What are Hall thrusters?
    • What are cold gas thrusters? When are they used and why?
    • What is the working principle of a solar sail? How is it possible to operate with it? Is it possible to go towards the Sun with a solar sail? What are the main problems related to its use? Is it possible to use a solar sail on LEO?
12. Navigation, guidance & steering
    • Why rockets are not stable? Are rockets with front engines more stable? Are rockets with multiple engines more stable?
    • What are pitch, yaw & row axes? What rotational directions are positive?
    • How does aerodynamic stabilization work? When is it available? Does it work better for larger or smaller rockets?
    • How does spin stabilization work? What advantages does in have? What are yo-weights?
    • How do movable air vanes work? When are they applicable?
    • What are jet vanes? What are their disadvantages?
    • What is the working principle of steering by gas/liquid injection into the nozzle?
    • What is the working principle of steering by gimbaled engines? What are the advantages and limitations of this method?
    • How is steering performed with vernier engines/nozzles? What is thrust differentiating? Why is it used rarely?
    • What are the tasks of navigation, guidance and control?
    • What are the working principles of autonomous navigation? What hardware is used for it? What is inertial navigation system and inertial guidance platform?
    • What non-inertial and non-autonomous methods of navigation are also applied in rocketry?
    • How does a guidance system work? What simplifications are used sometimes and why? What was special in guidance of the Lambda-4S? Of the Juno I? In the Luna-9 landing? In the Luna-16/20/24 ascent rocket guidance?
    • What is the open-loop control and the close-loop control? What is the open-loop navigation and the close-loop navigation? What advantages does the close-loop navigation have? How was it applied on the Saturn V?
13. Principle systems of rockets
    • What are principle designs of propellant tanks? What is frame structure and what is monocoque? What structures carry launch loads?
    • Why common bulkhead is sometimes applied? What is the task of slosh & vortex baffles? What shapes do propellant tanks have?
    • What is the problem to start an engine in the conditions of weightlessness? What methods are used to solve this problem?
    • Why propellant reserve is required? Why fuel is often loaded in excess? How does a propellant consumption control system work? How does close-loop navigation aids to reduce propellant reserves? Why some propellant still remains unburnt?
    • How does parallel staging usually organized? What are the reasons to use parallel staging? What are drawbacks of this solution?
    • What is serial staging? What are possible advantages of propellant transfusion between stages? What are the drawbacks?
    • What are mechanisms used to separate stages? What are the requirements of a safe separation? How are parallel stages jettisoned?
    • What is fire-in-the-hole separation method? What are its advantages and problems, how are these problems solved?
    • What is cold separation? What are is advantages and disadvantages? Why retrorockets are used? What is the task of ullage motors?
    • How length of interstages may be reduced?
    • What is Range Safety System?
    • What is the task of the nose fairing? When is it jettisoned?
    • What is the task of the Launch Escape System? How is it constructed? How does it work? What were the safety provision methods on the Vostoks and the Gemini? What are the safety provisions on the Shuttle? Have Launch Escape System ever saved lives of crew?
14. Systems of satellites & spacecraft
    • What are main power supply sources on spacecraft?
    • What are advantages and disadvantages of batteries and fuel cells? What is the working principle of fuel cells?
    • What are solar cells? What are their advantages and limitations? How are they organized on spacecraft? What are typical power rates on geostationary satellites? How quickly do solar cells degrade?
    • What types of nuclear energy sources exist? What are RTGs? When are they applied? Why they should be shielded? What is their degradation rate? What are RHUs?
    • What are advantages and disadvantages of nuclear reactors as power source? Where they have been used? How safety was ensured? What episodes with nuclear power sources do you know?
    • What are peculiarities of thermal control in space? What are mean heat sources and heat sinks? What passive and active methods of thermal control do you know?
    • What is multi-layer thermal insulation? What is its working principle? What roles does it play? How paints are used for thermal control? What are Optical Solar Reflectors?
    • What active thermal control methods do you know? What is the working principle of cooling and heating loops?
    • How thrust is used for attitude control? What is the Reaction Control System, what roles does it play? What engines does it include?
    • What are reaction control wheels and moment control wheels? What is their working principle, what advantages to they have? What are CMGs, what are their advantages and drawbacks? What is saturation of wheels and CMGs, why desaturation is required? How desaturation is performed?
    • What is gravity-gradient stabilization? When is it effective? How its efficiency may be increased? What is magnetic stabilization, what are Magnetic Torquers? How aerodynamic pressure may be used for attitude control, what are limitations of this method? How solar pressure may be used for attitude control?
    • What devices does communication system include? What tasks does this system perform?
    • What frequency range is used for communications and why? How does a transmitter and receiver work? Why Phase-lock loop is applied? What is transponder?
    • What is a high-gain antenna? What roles may it play? Why medium-gain and low-gain antennas are used as well? What happened to HGA of the Galileo probe and how the problem was resolved?
    • what are requirements space computer should meet? What are the most serious problems with digital computers in space? Why not the most powerful computers are installed on spacecraft?
    • What is the spacecraft clock? What data storage devices were used in the past and what devices are in use now? What is safing? How a spacecraft react to anomalies? What procedures are performed to restore normal work?
    • Why common buses are used to build satellites and space probes? What examples do you know? Why magnetometers need a long boom? Why RTGs need shielding? Why independently articulated platforms are used? How spacecraft basic systems may be used as science instruments?
    • What is the role of Life Support System? What tasks should it perform? How water is recycled on space stations? How oxygen is produced? What consumables are delivered? What is the importance of studies of closed-cycle Life Support Systems?
15. Launch
    • How latitude influences choice of a launch site? Why launch sites and azimuths are restricted geographically?
    • Why most of rockets are launched vertically? What rockets may be launched from a ramp?
    • What advantages and drawbacks does air launch have? What air-launched space rockets do you know? Why some space rockets are launched from submarines?
    • What are the advantages and disadvantages of vertical & horizontal assembly methods? How rockets are transported to launch pad?
    • What structures include a launch pad? What tasks does Launch Tower have? How is rocket secured to the launch pad? What are acoustic loads? What for are flame trenches & deflectors used? Why water is poured at launch of large rockets?
    • What are the propulsive losses? What is gravity loss, how does it depend on the pitch angle and ascent time?
    • What are the drag losses? At what heights are they most significant? What are steering losses, on what parameters does they depend?
    • How does characteristic velocity gain from the Earth rotation depend on latitude of the launch site and the azimuth of launch?
    • What is gravity turn? When is it applied?
16. Descent and landing
    • What are the factors influencing the choice of direct landing or landing from orbit scheme? How does landing scheme influence landing precision?
    • Give examples of intentional crash-landings. What are penetrators?
    • How atmosphere help to soft-land a spacecraft? What is deorbit burn? Why is it so important for manned spacecraft?
    • How g-loads of descent and total heat loads depend on entry angle? Why? What is skip reentry
    • Why is it impossible to convert totally orbital energy of a spacecraft into heat? How does orbital energy dissipate, what physical processes are involved? What is communication blackout and why does it occur?
    • What is the working principle of ablative protection and of heat sink? What is heatshield? Why is it jettisoned frequently after the orbital speed is canceled? How does heat shield of the Space Shuttle and Buran work?
    • What shapes of entry capsules are in use? What is ballistic descent? Why non-zero lift force is used? How steering is performed with the aid of the lift force? What roles does steering play? What are the advantages and drawbacks of wings?
    • Why parachutes are needed? What are drogue chute, pilot chute, stabilization chute? What braking devices Venus soft-landers applied? What are the problems of using chutes on Mars? What methods of increasing chute system reliability are applied on manned spacecraft?
    • How is landing on a celestial body without atmosphere performed? Why large-thrust and small-thrust engines, or a deeply throttled engine are required? Why rocket-powered descent is used on Mars? What equipment is used to determine position and velocity in respect to the celestial body?
    • What landing velocities are usually safe when landing on ground and on water? Why US manned capsules landed on water? How terminal velocity is canceled at a rocket-powered descent? What methods are applied at a parachuting descent? What are airbags, how do they work? What soft-lander has pioneered in using airbags?