question,propositions,labels,justification,answerable,uid
True or False? An object that is not accelerating or decelerating has no forces acting on it.,"['True', 'False', 'Impossible to say without more information']","[0, 1, 0]","According to Newton's first law: ""In the absence of a force, a body either is at rest or moves in a straight line with constant speed"". However, the opposit is not true. A body can have forces acting on it and not accelerate if the resulting force is zero.",True,ff0e8305-73e0-404a-a775-4e7be538d99b
"Complete the following: During its orbital period, as a planet moves farther away from the sun, the orbital velocity of the planet ...","['remains the same', 'increases', 'decreases']","[0, 0, 1]",,True,40a73e51-5eb4-46d3-baab-8acd624f2287
Which affirmation is true when talking about Earth’s potential energy?,"['The potential energy is positive', 'The potential energy is constant', 'The potential energy is negative', 'None of the above answers']","[0, 0, 1, 0]",This is because the Earth potential energy is expressed as Epot = - mu / r,True,883f8ed7-8b2a-4671-80d3-f68791fa4118
Why do we talk about microgravity in LEO?,"['All the external forces are not cancelling exactly', 'In LEO orbits, the Earth’s gravity is not exactly zero', 'The free-fall trajectory gets perturbed', 'None of the above answers']","[0, 0, 1, 0]",,True,7667b6ef-31e5-4ff3-87e2-65f9a4467551
To what wavelength is the atmosphere the most transparent?,"['X-rays', 'Visible light', 'Infra Red', 'Radio Waves']","[0, 0, 0, 1]",,True,b855830d-0498-4c21-8aca-ac69c917178c
"In the atmosphere and space environment, what best describes the so-called airglow?","['Photo ionization of oxygen', 'Northern lights', 'Diffraction of the Sun light in the upper layers of the atmosphere', 'Photo Ionization of Hydrogen']","[1, 0, 0, 0]",,True,e8663499-3be2-4284-88b1-6bada5682f75
"A rocket is launched from ESA spaceport in Kourou, French Guyana. Through which layers of the atmosphere and in what order the rocket will pass through?","['thermosphere, troposphere, stratosphere, mesosphere', 'troposphere, mesosphere, thermosphere, stratosphere', 'troposphere, stratosphere, mesosphere, thermosphere', 'troposphere, mesosphere, stratosphere, thermosphere']","[0, 0, 1, 0]",,True,1b6dbef8-074c-47b0-aba9-5b291196850d
What are the Van Allen belts?,"['The region between 90 and 100 km altitude', 'Low radiation regions', 'Much used orbits for telecommunication', 'Radiation belts']","[0, 0, 0, 1]","These are regions in which you have an increased density of charged particles, mainly protons and electrons, and they are moving to the North and to the South. They are trapped in these regions of increased flux of protons and electrons. Electrons are not too harmful, but protons could be.",True,9d24c8a3-5a62-4b10-a5c6-82a9a7173042
"Why is the inner radiation belt harmful for satellites, and more so than the outer belt ?","['Inner radiation modify the magnetic field and will damage optical system of satellites.', 'Inner radiation traps space debris which damage the structure of satellites.', 'Inner radiation traps protons which are more likely to damage on-board electronics.', 'the question is not correct, the outer belt is more harmful for satellites.']","[0, 0, 1, 0]","On top of electrons the inner radiation traps a significant amount of protons whose mass is much higher than the electrons. Because those protons carry more energy, they are also more likely to cause critical damage to the on-board electronics. One way to mitigate this problem is to harden the circuitry by applying redundancy as needed or by shielding the components.",True,45402b06-b7b3-46b0-ae5c-1d3ad697d8b4
"The sunspot number is a value that changes with time, with a period of approximately...","['7 years', '9 years', '11 years', '13 years']","[0, 0, 1, 0]",,True,920728e6-584b-46bd-b596-80aaab4ccfad
"True or False: the latitude of sunpots during a solar cycle stays uniform and constant, regardless of the sun activity","['True', 'False']","[0, 1]",,True,32387be2-0b71-47c8-abbf-b06d60781657
Which of the following statement(s) is or are correct(s) with respect to the solar cycle effect on satellite lifetime at a given altitude?,"['At solar maximum, you have higher atmosphere density, which means more drag, and reduced satellite lifetime', 'At solar maximum, you have lower atmosphere density, which means less drag, and and increased satellite lifetime', 'At solar minimum, you have higher atmosphere density, which means more radiation, and reduced satellite lifetime', 'At solar minimum, you have lower atmosphere density, when means less lift for the satellite, and reduced lifetime']","[1, 0, 0, 0]",,True,433d3c7b-4f56-4934-ac4b-d513d975c33b
"Based on your understanding of the solar cycle, where would be the best place to see auroras? (select all that apply)","['Close to Antarctic and Arctic circles', 'Near the equator', 'Iceland or northern Scandinavia', 'Latin America']","[1, 0, 1, 0]",,True,e8128a5b-c008-49cd-ba2e-e859042da89d
What would be the most appropriate time to observe auroras?,"['2018', '2023', 'anytime', '2029']","[0, 1, 0, 0]",,True,81c4c4ae-b178-4a9d-8f2d-1f9b1a2b4d52
What is the main driver of the shape of solar prominences ?,"['Van Allen radiation belts', 'Earth', 'Magnetic fields generated by the sun', 'The orbital forces of Mercury']","[0, 0, 1, 0]",,True,a5a8edfe-c124-4b53-99f4-bca48e0f12fc
What is the difference between CMEs (Coronal Mass Ejections) and prominences ?,"['CMEs do not reconnect towards the sun. They also emit in lower wave-lengths.', 'There is no difference', 'Prominences and CMEs appear at different times of the day', 'CMEs are only caused by radiation belt']","[1, 0, 0, 0]",,True,04ad623a-86b3-46ac-8762-ce379d9258cf
What is the typical lower boundary of the Van Allen belts?,"['Below the ISS altitude', 'Half-way to the Moon', '500-600 km, roughly the altitude of the Hubble Space Telescope', '200-300 km, roughly the altitude of the Hubble Space Telescope']","[0, 0, 1, 0]",,True,88326631-7955-4fcd-8bb7-1a2c73fd5dd0
What is the global shape of the Earth radiation belts?,"['Spherical', 'Rectangular', 'Toroidal', 'Triangular']","[0, 0, 1, 0]",,True,e7426a1d-3e9f-4a96-bf76-e39df49b5458
What is the sectional profile of the Earth radiation belts?,"['Banana-shaped, with the extremities away from the Earth', 'Banana-shaped, with the extremities close to the surface of the Earth', 'Rectangular', 'Disk']","[0, 1, 0, 0]",,True,6249156c-13d9-4ce4-9abf-46bf65e50b60
The activity of the Sun has a periodicity of 11 years. What are the methods to observe it? (Select all that apply),"['Count the number of sun spots', ""Measure the Sun's bolometric flux (i.e. the flux over the whole spectrum)"", ""Measure the Sun's flux in a spectral band called H-alpha"", ""Measure the Sun's flux at a wavelength of 10.7 cm""]","[1, 0, 0, 1]",,True,e61de4a5-23be-4d82-92d0-fea5117b41a1
The solar prominence are bright features extending far into space. They can last from a few dozen hours to months. What can be their size?,"['Up to the distance from the Sun to Mercury', 'Up to the distance from the Sun to Earth', ""A siginificant fraction of the Sun's radius"", 'Up to the size of the Earth']","[0, 0, 0, 1]",,True,2f361e84-1b61-42b8-85e7-382e098b3512
Coronal Mass Ejections (CMEs) are huge ejections of plasma from the Sun. What is their manifestation at a far distance (e.g. somewhere in the vicinity of Earth) from the Sun?,"['The flux of light from the Sun is lowered.', 'The Sun darkens from the observer point of view', ""None, it's too far away"", 'A gust of charged particles']","[0, 0, 0, 1]",,True,04660f0a-19fc-4b41-82c2-9f4c2245bf07
What is the magnetosphere?,"['A spherical object composed solely of magnetic material', 'A region that surrounds an object that has a magnetic field, usually a dipole which is distored by charged particles', 'A region in Indonesia', 'A region that surrounds an object that has a magnetic field, which tunnels neutral particles away from the object']","[0, 1, 0, 0]",,True,a279f385-4896-4877-8c32-c265ae0f6b31
"Some of the solar flux is reflected off the surface of the Earth. The fraction of sunlight reflected is given by the albedo. If the albedo increases, how will the amount of reflected light change?","['It increases', 'It descreases', 'It stays the same', 'Impossible to say, we need more information to answer']","[1, 0, 0, 0]",,True,dea1ba45-fcb4-454c-ab94-8a06a4d4f2f4
Crossing the South Atlantic Anomaly (SAA) with a satellite can greatly restrict its performance. Why?,"['The SAA is a region of permanent shadow over the South Atlantic, thus there is no power generated by the solar panels.', 'The SAA is a region of extremely high radiation. Radiations create errors in the onboard electronics which can potentially be permanent.', 'The SAA is a region of extremely low radiation. This induces large currents in the onboard electronics which degrades the performance.', 'The SAA is a region which is not covered by any array of antenna, which renders any communication between the ground and the satellite impossible.']","[0, 1, 0, 0]",,True,8b9f71e4-c6db-45d7-8199-a83a58c31074
An object X and an object Y are in orbit (at the same altitude). X has a Drag Coefficient of 2 while Y has a drag Coefficient of 2.2. Which object will first fall back to Earth?,"['Object X', 'Object Y', 'Both at the same time', 'Impossible to say']","[0, 0, 0, 1]",The masses and cross-sections have to be given to be able to estimate which will fall back first.,True,274915a7-1ad4-49f5-979e-c38c3994eba4
"Space debris mitigation rule states that after end of nominal operations, a satellite has to fall back to Earth or to be put on a graveyard orbit within","['23 years', '24 years', '25 years', '42 years']","[0, 0, 1, 0]",,True,20566fe9-5314-4bb3-a0b7-4e9f01f8c396
Hubble's solar arrays were damaged because of collisions with:,"['Orbital debris', 'Meteorites with a 10e-5 cm diameter', 'Meteorites with a 10e-2 cm diameter', 'Meteroites with a 10 cm diameter', 'The famous cosmos-irridium breakup that destroyed the primary mirror of the telescope']","[1, 1, 1, 0, 0]",,True,80824e85-50b6-4981-9056-5f91e3bd6326
The International Space Station (ISS) is placed on an elliptical orbit around the Earth. The orbital apogee is 417 km and orbital perigee is 401 km. What is the gravitational acceleration created by the Earth at the orbit perigee?,"['1.72 m/s^2', '8.68 m/s^2', '0 m/s^2', '7.78 m/s^2']","[0, 1, 0, 0]",,True,2772845a-52cb-4686-8cfe-b19647b0ad18
"What is the escape velocity from the surface of the moon Europa (mass M = 4.8e22 kg, radius 1560 km)? (answer in km/s)","['Approximately 1', 'Approximately 2', 'Approximately 3', 'Approximately 4', 'Approximately 5']","[0, 1, 0, 0, 0]",The escape velocity of Europa is simply computed from Vesc = sqrt( 2*mu / R) which is approximately 2 km/s,True,90c76998-7060-491c-a0fb-3ae580a72a22
The escape velocity out of the solar system from Jupiter's orbit is 18.5 km/s while the average orbital velocity is 13.1 km/s. What is the transfer velocity in km/s?,"['0.2', '1.4', '2.7', '3.6', '5.4']","[0, 0, 0, 0, 1]","The transfer velocity, for a given planet, is the velocity that has to be added to the planet's circular velocity for a transfer to infinity from this location in the Sun's gravitational well. Therefore, the transfer velocity out of the solar system is 18.5 - 13.1 = 5.4 km/s.",True,6df3d9f1-800e-4b7d-b9ca-ce2ef8090718
The comet 67P/Churyumov-Gerasimenko has an escape velocity close to 1 m/s. What would be sufficient in the following to escape its surface and never come back ?,"['You, by jumping the equivalent of 50 cm on Earth.', 'A tennis ball hit by Roger Federer.', 'A bullet shot by a pistol.', 'None of the above.']","[1, 1, 1, 0]",,True,dcd48a6f-2c96-42e6-b75e-b5cb28b2c1fa
"The Rosetta spacecraft launched by the European Space Agency successfully entered the orbit of the comet 67P/Churyumov-Gerasimenko in August 2014. November 12 2014, the Philae lander was released and touched down 7 hours later at a speed of 0.98m/s. The harpoon mechanism which was supposed to secure the lander failed and it bounced off the comet. Assuming purely elastic impact, will the lander leave the comet or return at some point?","['For sure, the lander is lost.', ""The lander's chances are fair, but there is a significant risk."", 'All is good, not to worry, Philae will come down for sure.']","[0, 1, 0]",,True,6570bf60-a707-4f9b-ad31-d7bf390a306f
Telecommunications satellites are often on geostationary orbits (GEO) at an altitude of 35786 km above the surface of the Earth. What is the Earth escape velocity from that orbit? (answer in km/s),"['4.7', '5.0', '5.3', '5.6', '5.9']","[1, 0, 0, 0, 0]",,True,cfaa1256-9ed3-460b-b6d4-2a79e2b335f2
"Which formula gives the work to be performed in order to bring a unit mass from the Earth's surface to infinity? Assume that g0 is the standard gravitational acceleration for the surface of the Earth, R is the radius of the Earth, and p the atmospheric pressure.","['g0 * R * p^2', 'g0 * R * p', 'g0 * R', 'g0 * R^2']","[0, 0, 1, 0]",,True,bef97b27-a677-488c-9088-b835c0f3d1a8
"What is the formula to compute the escape velocity given mu (standard gravitational parameter), and r (the distance to the center of the central body)?","['V = mu * r', 'V = sqrt( 2 * mu / r^3 )', 'V = sqrt( mu / r )', 'V = sqrt( 2 * mu / r )', 'V = sqrt( mu / 2r )']","[0, 0, 0, 1, 0]",,True,57080b4d-b331-4816-985f-c76f499662f6
"The gravitational acceleration at the altitude of the ISS is about 8.68 m/s. However, the astronauts onboard the station are in weightlessness. Why?","['The ISS is constantly rotating around its main axis, creating the illusion of weightlessness.', 'The ISS is constanly falling towards the Earth, but with enough horizontal speed to create an opposing acceleration and equal in magnitude to the gravitational acceleration.', 'Thrusters are in constant use which generate a force such that there is weightlessness.', 'None of the above.']","[0, 1, 0, 0]",,True,808bd743-7703-452b-a0bb-05516948c7d4
A spacecraft is on a free trajectory in the vicinity of the Earth. From which statement can it be deduced that this spacecraft has sufficient energy to leave Earth's gravitational well (i.e. it is not on orbit around the Earth)? Assumption: Etot refers to the total energy of the spacecraft.,"['Etot >= 0', 'Etot < 0', 'Etot is close to + infinity', 'Etot is close to - infinity']","[1, 0, 0, 0]",,True,0d0d9c07-d33a-4624-9597-1222c4479572
The transfer velocity from an 1 AU orbit (i.e. Earth's orbit) is about 12 km/s. The transfer velocity from Mercury's orbit is 20 km/s. A probe is on an 1 AU orbit with the objective of going towards Mercury. What action must be taken?,"['Decrease the energy of the probe.', 'Increase the velocity by 12 km/s.', 'Wait until the orbit is perturbed enough to flyby Mercury.', 'Increase the energy of the probe.']","[1, 0, 0, 0]",,True,169dbc4a-48cf-40f8-b67b-654da412029f
What is the orbital velocity of the Hubble Space Telescope which is on a circular orbit at 555 km altitude? (answer in km/s),"['4.00', '6.21', '7.58', '8.02']","[0, 0, 1, 0]",,True,5f013dd6-d16e-4e1f-91f2-84dd2711e47c
What is the strength of the Earth’s acceleration in LEO?,"['Same acceleration than on the surface of the Earth', 'No acceleration, that’s why you can float in space', '90% of the acceleration on the surface of the Earth', '10% of the acceleration on the surface of the Earth']","[0, 0, 1, 0]",,True,7b343016-967c-4a4c-a892-be3e07a6992b
Which of the following proportionnality relation with the orbital period T with respect to the semi-major axis a is correct?,"['T^2 is proportional to a', 'T^2 is proportional to a^2', 'T is proportional to a', 'T is proportional to a^(3/2)']","[0, 0, 0, 1]",,True,503e9f15-7799-4813-b0ad-b87c053b9cc3
An artificial Earth satellite is in an elliptical orbit with a perigee altitude of hp = 250 km and an apogee altitude of ha = 800 km. What is the correct expression of the orbital period?,"['T = 2*pi * sqrt( a^3 / mu )', 'T = 2*pi * sqrt( a^2 / mu )', 'T = 2*pi * sqrt( a^(1/2) / mu )', 'T = 2*pi * a^3 / mu']","[1, 0, 0, 0]",,True,176ce268-f5ed-4c3e-bf98-b53c8c63fed0
"An artificial Earth satellite is in an elliptical orbit with a perigee altitude of hp and an apogee altitude of ha. How do you express the semi major of the axis of the satellite orbit ""a""  in function of hp, ha, and R where R is the Earth's radius?","['a = R ( hp + ha ) / 2', 'a = R ( ha - hp ) / 2', 'a = 2R + (ha + hp) / 2', 'a = R - (hp + ha) / 2', 'a = R + (ha + hp) / 2']","[0, 0, 0, 0, 1]",,True,874c48df-381b-4887-a2b8-fa09963fbb2f
An artificial Earth satellite is in an elliptical orbit with a perigee altitude of hp = 250 km and an apogee altitude of ha = 800 km. What is its orbital period expressed in minutes?,"['18.0', '89.5', '95.0', '100.9']","[0, 0, 1, 0]",,True,6ef8b7da-7aea-4809-95ce-c17f64866bee
A geostationary orbit is defined as an orbit were the satellite is always pointing towards the same point on the Earth's surface. What is its eccentricity?,"['0', '1', '1.3', '0.5']","[1, 0, 0, 0]","Since the Earth's rotation is constant, the eccentricity of the orbit is zero, otherwise its orbital velocity would not be constant.",True,5064e3a3-16e9-431c-816e-3d8cd10c9331
A geostationary orbit is defined as an orbit were the satellite is always pointing towards the same point on the Earth's surface. What is its inclination?,"['7.01°', '0°', '3.2°', '45°']","[0, 1, 0, 0]",The inclination is also zero otherwise the satellite's pointing would oscillate across the equator.,True,6192c62d-489d-45e4-acf6-23083a809273
"In orbital mechanics, what is the meaning of the mean motion n = sqrt( mu / a^3 )?","['It is the average angular rate over one full orbit, in rad/s', 'It can be defined only for parabolic orbits.', 'It corresponds to the instantaneous angular rate for a non-circular orbit.', 'In the specific case where the eccentricity e tends to zero, the mean motion and the true anomaly tend to be equal.', 'The mean motion relates to the true position of a body moving along a Keplerian orbit.']","[1, 0, 0, 0, 0]",,True,bc2f3517-6e5a-4b39-89c6-fb11c2209392
What reference frame is the best suited for an interplanetary probe?,"['Geographic coordinate system', 'Geo-centric coordinate system', 'Heliocentric-inertial coordinate system']","[0, 0, 1]","The center of the heliocentric-inertial coordinate system is the Sun. The two other coordinate systems use the Earth as center, and are not appropriate to for an interplanetary probe.",True,8d7cc580-c7b9-4875-9ba6-bf468df0a61d
The complete precessional cycle of the Earth lasts about 26000 years. What is the precession rate? (in degrees per year),"['0.00384', '0.01384', '0.02384', '0.03384', '0.04384', '0.05384']","[0, 1, 0, 0, 0, 0]",The precession rate per year is 360°/26000 years = 0.0138°/years.,True,e4fda0e7-b147-48fd-bcea-fbc007d2ee9b
What is the RAAN?,"['The inclination of the orbital plane.', 'The time of the periapsis transit.', 'The angle from a reference direction to the point where the satellite crosses the plane of reference, towards the south.', 'The angle from a reference direction to the point where the satellite crosses the plane of reference, towards the north.']","[0, 0, 0, 1]","The longitude of the ascending node (Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude, to the direction of the ascending node, measured in a reference plane.",True,7c7013ed-cb14-4298-a435-259072390c40
How long is a sideral day?,"['24h00min', '24h04min', '11h56min', '23h56min']","[0, 0, 0, 1]","The sidereal day, is the time it takes for the Earth to make one full rotation with respect to the stars, 23h56'04''.",True,e5939e55-2802-4753-b849-2efdd4aafa9a
Where is an orbital maneuver Delta-V adding energy to a spacecraft on orbit best performed?,"['Along the orbital velocity', 'Radially', 'Along the orbit angular momentum', 'Any direction of the Delta-V vector will add energy to the spacectaft on orbit.']","[1, 0, 0, 0]","In the impulsive case, only maneuvers along the velocity will impact the energy. Radial and cross-track maneuvers will only change the direction of the speed without changing its norm.",True,3e8adab1-90a8-4d92-a636-f514f12d90cf
What is the Hohmann transfer for small Delta-V useful for?,"['Interplanetary trajectories', 'Earth-Moon transfer', 'Manoeuvers around small bodies (e.g. comets)', 'Orbital rendez-vous']","[0, 0, 0, 1]",,True,b706586d-50b8-4d17-b9f2-890c679ff6e8
Where is the Delta-V for an inclination change smaller?,"['at low altitudes', 'at high altitudes', 'at the equator', 'at the poles']","[0, 1, 0, 0]","The Delta-V for inclination change is proportional to the orbital velocity. Thus, the smaller the orbital velocity is, the less is required to change the inclination and RAAN. The orbital velocity decreases with the square of the distance from the center of the body, thus higher altitudes are better.",True,a972601f-0015-48b8-8747-5e5dd8e92e12
What is the difference between geostationary and geosynchronous orbits?,"['Geostationary has an orbital period of 24h whereas geosynchronous orbits is 23h56', 'The orbital parameters for geostationary are inclination = 0° and eccentricity = 0', ""A geosynchronous satellite orbits the same location over Earth's surface while a geostationary satellite remains on average at the equator"", 'All of the above']","[0, 1, 0, 0]","A geostationary satellite orbits the same location over Earth's surface while a geosynchronous satellite remains on average at the equator. The definition of geostationary orbits is orbital period is Earth's sideral day, e = 0 and i = 0°",True,e723f537-9123-4794-99c4-6dc0f39f9e8f
The ground tracks for a satellite in LEO (typical orbital period is 90 min) is shifting to the west from one equator crossing to the next. What is the typical value of the shift in degrees?,"['12.5', '15', '17.5', '20', '22.5']","[0, 0, 0, 0, 1]","At LEO altitudes, the typical orbital period is 90 min. In an hour the Earth rotates by 15° (= 360° / 24h), thus in 90 min, we have a shift of 22.5°",True,60f3877b-24ba-45fe-af9e-d67d14170174
"For a circular orbit of a given inclination, at what altitude will a satellite be impacted the most by nodal regression?","['200 km', '2000 km', '500 km', '12000 km']","[0, 0, 0, 0]","The lower the satellite, the stronger the effects of the nodal regression.",True,f9c603e5-f517-4636-849f-350a2759fcdc
"Among the following assertion about Lagrange points, which one is true?","['The Sun-Earth system does not have any Lagrange points because of the Moon', 'The distance between the Lagrange points and the Earth varies drastically with the seasons', ""The Lagrange points orbit the Sun with the same orbital period as the Earth's"", 'None of the above']","[0, 0, 1, 0]",The Lagrange points orbit the Sun with the same orbital period as the Earth's. The mass of the satellite on a Lagrange point is adjusted (lessened in the case of L1 and highthened for L2) such that the orbital period remains one year.,True,41c719d0-9f62-40da-abeb-8bd99a86ef8b
"A spacecraft is below and behind the ISS, both are on circular orbits. What will happen to their relative position?","['The spacecraft will overtake the ISS', 'The ISS has a larger velocity than the spacecraft, so it will leave the spacecraft behind', 'Nothing, they will stay at their initial distance', 'The spacecraft will get to an higher altitude than the ISS']","[1, 0, 0, 0]",The orbital velocity decreases with altitude (with the square root of the inverse to the distance to Earth's center). Thus the spacecraft moves faster and will catch-up with the ISS and eventually overtake it.,True,a2db30ce-3528-4548-a228-c27b103a545c
What is the effect of a posigrade burn on a circular orbit?,"['There is no effect', 'The altitude 90° from the burn point is decreased', 'The altitude 180° from the burn point is decreased', 'The altitude 180° from the burn point is increased']","[0, 0, 0, 1]","At the burn point, the velocity is increased. It means that the energy of the spacecraft changes and the geometry of the orbit changes. The altitude of the burn point will not change, but becomes the minimal altitude if the initial orbit is circular. Its maximum will be reached at the apogee, 180° from the perigee. Thus the altitude 180° from the burn point is increased.",True,11665c59-aacf-437d-b83e-16aaa6921ced
What is the reference point of the rendezvous profile diagram?,"['The chaser', 'The target', 'The center of the Earth', 'The control center']","[0, 1, 0, 0]",The rendezvous profile diagram is centered and relative to the target.,True,a28c168f-3f6a-4edb-b0c0-2ae974963858
"What is the shape of a circular orbit, for the chaser, in a rendezvous profile diagram? (assuming the target is higher than the chaser).","['A point', 'A periodic wavy and pointy curve', 'A line', 'A sinusoidal', 'A cycloid']","[0, 0, 1, 0, 0]","On a circular orbit, the altitude does not change, so the value of the R axis does not change. The V axis does not stay the same as the velocity of the two spacecraft are not the same. The chaser will move along an horizontal line in the diagram.",True,e8b2cae4-92f6-48e6-9436-c5f33a5ac832
A spacecraft on a circular orbit at 400 km does a retrograde burn of 1 m/s. What will be the change in the altitude (in km) of the perigee?,"['1.5', '2.5', '3.5', '4.5']","[0, 0, 1, 0]",This can be computed in a straightforward way using the equation Delta-r is close to 3.5 * Delta-V where Delta-r is in km and the burn value in m/s.,True,61e3c07e-fd5e-4429-aeb1-66afe0919eda
A chaser is on a circular orbit at the same altitude as the target and few kilometers behind. Where will the chaser be one orbit after a posigrade burn ?,"['The chaser will be much further ahead', 'The chaser will be behind the target, further away than it was initally', 'The chaser will be higher than the target', 'The chaser will be lower than the target']","[0, 1, 0, 0]","Since there is a posigrade burn, the altitude of the semi-major axis is increased, the orbital velocity is decreased. If the change of altitude is sufficient, the chaser will drift behind the target further away than it was initially.",True,9fc96902-8398-4630-b53b-6d3049c8254e
What is the definition of the Astronomical Unit (AU)?,"['It is the average distance between the Earth and the Sun', 'It is the average radius of the solar system', 'It is the average radius of the Sun', 'It is the average distance betwteen the Moon and the Earth']","[1, 0, 0, 0]","An Astronomical Unit is the mean distance between the Earth and the Sun. In 2012, the International Astronomical Union defined the distance to be 149,597,870,700 meters.",True,3fedeb91-5ab5-45de-be70-a2ce8ad59e10
What is the sphere of influence?,"['A region in space that can be controlled by a spacecraft', 'The region around the Sun in which only planets have a gravitational influence', 'A sphere around each planet inside which the motion of a spacecraft must be considered a three-body Keplerian problem', 'A sphere around each planet inside which the motion of a spacecraft is considered to be two-body Keplerian']","[0, 0, 0, 1]","For the Earth, the radius of the sphere of influence is about 924 000 km.",True,6a0ff5bb-46cb-4b10-a12b-4573589bb59f
What is the hyperbolic excess velocity?,"['The velocity required to get into a LEO orbit from the surface of the Earth', 'The velocity at which we cross the sphere of influence', 'The velocity needed to reach the arriving planet', 'The velocity needed to reach the sphere of influence']","[0, 1, 0, 0]",It is the speed in excess of the minimum velocity required to reach the sphere of influence.,True,f274dd2f-9811-4424-abca-f3c6e4c61bd8
"A interplanetary probe is in the sphere of influence of the Earth, in transit towards an inner planet. What is its energy with respect to the Earth?","['E <= 0', 'E < 0', 'E = 0', 'E > 0']","[0, 0, 0, 1]","The energy for the hyperbola is epsilon = + mu / 2a (energy per unit mass), thus positive. Another way to see this, is that the probe is no longer gravitationally bounded to the Earth, ergo its energy is positive.",True,42d75d3d-7aed-4cc3-a784-814bfc3e0fd6
"What is the ideal shape of the transfer trajectory between two planets, and why?","['A Hohmann transfer orbit, because it is the less expensive orbit in terms of energy', 'A straight line, because is it the shortest path', 'A Hohmann transfer orbit, because it is the shortest path', 'A straight line, because it is the less expensive orbit in terms of energy']","[1, 0, 0, 0]","The Hohmann transfer is the optimal and ideal trajectory in terms of time of flight and fuel. However, in reality, different trajectories are preferred. For Mars transfer, more energetic trajectories are usually preferred to shorten the time of flight.",True,b2345b77-cb06-476f-82f4-092f001b8356
"An interplanetary probe is in transit towards an inner planet, very close to the arrival planet. How is the velocity of the planet with respect to the velocity of the probe?","['faster', 'identifical', 'slower']","[0, 0, 1]","The transfer ellipse ressemble a Hohmann transfer to go from a high to a lower orbit, thus the velocity of the probe is higher than the arrival planet. When leaving the Earth, the probe should also reduce its heliocentric speed. This can be done by crossing the sphere of influence with the velocity vector of the spacecraft in the opposite direction of Earth's velocity vector.",True,e344b8fb-a2cc-42b2-979c-544644a2a5b0
There is no burn during the slingshot maneuvers and yet the speed in the heliocentric reference frame increases. How is that possible?,"['At the periapsis of the slingshot, some massive object is jettisoned', 'An ion thruster is systematically switched on and this type of propulsion is only efficient in planetary neighborhood', 'The velocity vector of the probe is not changed in norm, but in direction in the planetocentric reference frame']","[0, 0, 1]","The norm of the velocity vector stays constant, there is no acceleration in the direction of the velocity vector. However, the direction of the trajectory of the spacecraft in the sphere of influence of the planet is a hyperbola. The direction of the velocity vector changes when the spacecraft is inside the sphere of influence.",True,6012cf0f-5cb3-440a-a35b-91c61539f393
What can Gravity-assist be used for? (more than one answer possible),"['Increase the heliocentric velocity', 'Decrease the heliocentric velocity', 'Make communications between the probe and Earth easier', 'Explorations of ""worlds"" during the transit flight to the destination']","[1, 1, 0, 1]","The most common application of gravity assist is to increase the heliocentric velocity. However, it can be reduced if the direction of the spacecraft velocity vector is well chosen when entering the sphere of influence. Voyager and Pioneer probes took advantage of their multiple gravity assist maneuvers to explore and take close-up images of all the planets in our solar system. This was made possible due to a particularly favorable alignement of the planets.",True,bb3def0d-b962-4777-84f9-bdd55055516a
"In space propulsion, what is true about the specific Impulse (Isp)?","['It is expressed in seconds', 'it changes with the gravity value g', 'it is an expression of the propulsion system efficiency', 'It is related to the exhaust velocity', 'It expresses the impact of the local gravity on the launcher capability to reach orbit.']","[1, 0, 1, 1, 0]",The Isp is related to the exhaust velocity by multiplying its value always by g=9.81. This relation is not dependant on the local value of the gravitational acceleration.,True,63bea71f-58f0-4e0a-a5c1-1ba58f8c927c
There are various combinations of fuel and oxidizer which exist. Which combination gives the biggest Isp among the following?,"['LOX/LH2', 'N2H4/LOX', 'N2H4/N2O4', 'Kerosene/N2O4', 'MMH/N2O4']","[1, 0, 0, 0, 0]",The LH2/LOX mixture provides an Isp of ~450s in vacuum. It was used for the Space Shuttle main engine and for the Ariane 5 vulcain engine for instance.,True,19654539-bab9-49dc-96ce-3bf60d2aa5be
Why is electric propulsion system more efficent than chemical propulsion?,"['It does not generate heat.', 'It produces a higher exhaust velocity.', 'Because of the recombination of ions and electrons to form neutral atoms.', 'Because of the production of electrodynamics shock waves at the exhaust.']","[0, 1, 0, 0]",,True,1397b4df-ea27-4305-9089-6292f6408abc
In the process of Orbit insertion what does MECO refer to?,"['Micro-Elliptic Catapult Orbit', 'Main Engine Cut-Off', 'It does not mean anything relevant']","[0, 1, 0]",,True,9f48dd27-ffa4-4042-8bbd-b9ff30e365c4
Which of the following statements are true?,"['LVLH is a coordinate system', 'LVLH is a french luxury clothing brand', 'LVLH is an inertial coordinate system', 'In the LVLH system, the z-axis points towards the center of the Earth', 'LVLH stands for Local Vertical, Local Horizontal.']","[1, 0, 0, 1, 1]","The LVLH, Local Vertical, Local Horizontal, is a local reference frame which is linked to the Earth's ground. x is in the direction of travel and z towards the center of the Earth.",True,bde40118-169c-4667-b624-b4742c2e3348
"In orbital manoeuvres, is the order of the Euler sequence commutative? (i.e. can you inverse two or more rotations)","['Yes', 'No']","[0, 1]",,True,2c39dc9e-9e69-4c79-b23f-2c28cce8dd83
How does a magnetic torquer work ?,"['The needle of a compass presses on the thruster button to correctly orient the spacecraft', ""A coil is wrapped around an elongated rod. An electrical current runs through the the coil generating a magnetic field which has the tendency to align itself with Earth's magnetic field"", 'Permanent magnets are placed at strategic places in the spacecraft, keeping it correctly oriented']","[0, 1, 0]",,True,b9b75cd4-9c1f-4195-b471-25be0cd57a14
"Solar arrays should be oriented towards the Sun with a very low accuracy. The angle Theta from the normal of the solar array to the Sun, however, is directly linked to the power generated. Why is the requirement the pointing of the solar arrays to the Sun so loose?","['The power generated is proportional to sine of Theta', 'The power generated is proportional to the cosine of Theta', 'The individual solar cells can points each towards the exact direction of the sun', 'We cannot point a higher precision']","[0, 1, 0, 0]","cos(10°) ~ 0.985, still very close to 1, the supplementary computational, electrical and even consumable needed to increase the power generated by 1 point is not always worth the effort. This lessen also the constraints on the attitude of the spacecraft to give more possibilities to the payload.",True,554f161d-df31-425b-aaa6-c95ef48d9b48
Select all propositons that applies to attitude maneuvers with thrusters,"['It is the most precise technique', 'It can be used to desaturate other attitude maneuver systems', '6 thrusters are needed to have pure rotations', 'A minimum of 12 thrusters are needed to have pure rotations', 'All thrusters systems need to have a ignition system']","[0, 1, 0, 1, 0]","Thruster is a very simple and quite crude method.
Thrusters are used to desaturate reaction wheels.
12 thrusters (4 per axis) are needed to be able to rotate and brake without translation.
All thrusters systems don't need to have a ignition system:  for example MMH/N2O4 is a hypergolic reaction and does not need an ignition system. For mono-propellant thrusters, the Hydrazine is catalysed on a berilium substrat.",True,fc1295d7-07f9-4a04-b7d7-f0d9a27720df
What is the fundamental principle that is used when working with rotation wheels?,"['Conservation of momentum', 'Conservation of angular momentum', 'Conservation of electric charge', 'Freedom']","[0, 1, 0, 0]","When the rotation wheel starts to rotate, the spacecraft will counter-rotate in order to conserve its total angular momentum, thanks to this, the attitude of a spacecraft can be modified",True,a4854768-4cb1-4483-a41e-e2565d01ebbc
What was the main power source of the Space Shuttle?,"['Solar arrays', 'Fuel cells', 'Radioisotope Thermoelectric Generators (RTG)', 'Hamsters running in a wheel', 'Astronaut bicycle ergometer with a generator']","[0, 1, 0, 0, 0]",,True,d9a55108-1a19-48eb-9069-a847b7a02f0b
A tether deployed from the Space Shuttle with a passive satellite at the end can be used as ...,"['Electrical Generator', 'Space elevator', 'Electrical motor', 'Dipole antenna']","[1, 0, 1, 0]",,True,b13d3f2d-ed82-43fc-a442-7276c41661d2
Which effect dominates the forces on a tethered systems?,"['Drag disturbances', 'Radiation pressure', 'Gravity gradient', 'Collision with other spacecraft']","[0, 0, 1, 0]",A collision with another spacecraft is very unlikely. The dominant effect is the gravity gradient which tends to align the system along the orbital radius.,True,84b8c9af-0b86-4e27-b1c9-eeff18b5dcd5
What elements were part of selected configuration of the Space Shuttle? (Select all that applies),"['An orbiter', 'A capsule', '3 main engines', 'Two solid rocket boosters', 'An external tank', 'A third stage']","[1, 0, 1, 1, 1, 0]",,True,102c8ce4-14c0-4b6b-a584-cdc889e6f12b
During which year the Shuttle approach and landing tests took place?,"['1974', '1975', '1976', '1977', '1978']","[0, 0, 0, 1, 0]",,True,f16dafd8-ba8c-4f1f-992b-f5c46867e858
Up to how many crew-members could participate in Space Shuttle Missions?,"['2', '5', '7', '10', '11']","[0, 0, 1, 0, 0]",,True,7809da4f-3612-4c97-b146-440b5425bca2
Which abbreviations correspond to real Space Shuttle Missions? (Select all that applies),"['STS-1', 'STS-432', 'STS-75', 'STS-51L', 'STS-137', 'STS-118']","[1, 0, 1, 1, 0, 1]","STS-1 was the first Shuttle flight in 1981, STS-51L corresponds to the Challenger accident in 1986, STS-75 was Claude Nicollier's third flight in 1996 with a tethered satellite. The last Shuttle flight was STS-135 so STS-137 and STS-432 do not make sense.",True,6167effd-5661-488b-a91b-01856dc8a560
What changes did occur after the Challenger accident? (Select all that applies),"['The design of some components of the Space Shuttle Transportation System was modified', 'Crew to the ISS were sent only with Soyuz spacecraft', 'The Launch and Entry Suit was introduced', 'The Shuttle was not used by the Department of Defense or for commercial flights', 'Nothing']","[1, 0, 1, 1, 0]",,True,e26b1a0e-e633-43a7-9191-84614aaaa4ee
When did the ISS start to be assembled?,"['2001', '1995', '1998', '2011']","[0, 0, 1, 0]",,True,e5d95638-231a-474a-912a-c7880d3db90d
"Which of the following vehicles were able to bring crews to the ISS, until 2011? (Select all that applies)","['Soyuz', 'Progress', 'Dragon', 'Space Shuttle', 'Shenzhou']","[1, 0, 0, 1, 0]","Only Soyuz spacecraft and the Space Shuttle were able to bring crews to the ISS. Shenzhou is the Chinese manned spacecraft which have been able to bring Chinese crews onboard the Chinese Space Station. Progress and Dragon are supply vehicles, not manned.",True,79d76e22-fdf1-4988-a33d-4eb00f028fb7
What year did the first spacewalk take place?,"['1962', '1963', '1964', '1965']","[0, 0, 0, 1]","The first spacewalk, realized by Alexei Leonov, took place on March 18, 1965 during the Voskhod 2 mission and lasted for 12 minutes.",True,3f36e2d1-f565-4e93-a265-d47774d48919
What new item was introduced in Apollo 15 to explore the Moon?,"['A second, scientific, deck to the LEM', 'A Lunar Roving Vehicle', 'A tent-like structure to analyze boulders', 'The spacesuits featured cold gas thrusters to fly small distances']","[0, 1, 0, 0]","The A Lunar Roving Vehicle called ""buggy"" was electrically powered and was driven on Apollo 15, 16 and 17, the last three flights. During Apollo 17, it was driven on the surface for more than 20 km!",True,df3bd299-9a98-41e0-910c-2bc81b057023
Which of the following is NOT a branch within the European Cooperation for Space Standardization (ECSS) system?,"['Policy branch (P-branch)', 'System description branch (S-branch)', 'Environmental Sustainability branch (E-branch)', 'Configuration and information management branch (D-branch)']","[0, 0, 1, 0]","The ECSS system includes several branches that cover a wide range of standardization disciplines, but an Environmental Sustainability branch (E-branch) as described is not one of them. The actual E-branch within ECSS refers to the Engineering branch, which defines standard engineering processes and technical requirements for space systems. The ECSS space sustainability branch (U-branch), was initiated in 2012, and defines two disciplines: space debris mitigation and planetary protection.",True,e1cb1e26-e334-478b-9cdb-2a4786585402
Which ECSS standard series focuses specifically on the product assurance aspects of space projects?,"['E-branch', 'S-branch', 'Q-branch', 'P-branch']","[0, 0, 1, 0]",The ECSS product assurance branch (Q-branch) defines the methods and requirements relevant to assure the safety and reliability of space products.,True,53550861-e6fe-46fb-ab3d-a059fda50de8
The South Atlantic Anomaly (SAA) is an area where the Earth's inner Van Allen radiation belt comes closest to the Earth's surface. What does it lead to?,"['A screening from sun light.', 'A decreased flux of energetic particles.', 'An increased flux of energetic particles.', 'A high number of auroras.']","[0, 0, 1, 0]",It leads to an increased flux of energetic particles in this region and exposes orbiting satellites to higher than usual levels of radiation. The effect is caused by the non-concentricity of the Earth and its magnetic dipole.,True,d1daaa31-090c-450f-a947-5fbe99bdcf52
What might be the effect of the impact of a cosmic ray with the onboard electronics? (More than one answer possible),"['Change the position of the satellite.', 'Create single event upsets.', 'Create single event latchups.', 'Cause the loss of performance of the system.']","[0, 1, 1, 1]","Single-event effects (SEE), mostly affecting only digital devices. When a high-energy particle travels through a semiconductor, it leaves an ionized track behind. This ionization may cause a highly localized effect. Single event upsets can be fixed by rebooting the system while single event latchups create a permanent localised failure, which in turn can result in loss of performance (that's why all electronic component are redundant on satellites).",True,96aee273-ea94-47ef-bb24-2748f7d7efae
What causes the difference between the spectral irradiance at the top of the atmosphere and at sea level?,"['The passage of airplanes', 'The presence of water in the atmosphere', 'The presence of CO2', 'The high albedo (about 0.9) at the poles']","[0, 1, 1, 0]",A lot of the solar flux is absorbed by different molecules present in the atmosphere. Certain regions of the atmosphere (in the UV for example) are opaque as the water molecule absorb all the available energy at that wavelength.,True,5cbdcce5-5cb1-489e-8750-cf2778362dfa
A probe is leaving the vicinity of Earth to fly to Mercury. Where will the solar panels generate the most power?,"['In the vicinity of Earth.', 'Mid-flight from the Earth to Mercury.', 'In the vicinity of Mercury.', 'The distance to the Sun does not matter.']","[0, 0, 1, 0]","The solar irradiance decreases with the square of the distance to the Sun. Closer objects will receive more solar flux, thus more power is generated in the vicinity of Mercury than in the vicinity of Earth.",True,04ac75a0-ba3b-4c49-bf33-8105794ad710
The Earth receives an almost constant flux from the Sun of S = 1361 W/m^2. Which of the following is correct?,"['All the energy received is funnelled to the core of the Earth to keep it at a constant temperature.', 'The Earth reflects most of the energy received and is kept in its thermal equilibrium by the heat source in its core.', 'The Earth is in constant shadow due to the multitude of satellites that orbit, such that it is in thermal equilibrium.', 'The Earth is in thermal equilibrium because some of the heat received is reflected back to space and the Earth radiates away energy, mostly in the IR.']","[0, 0, 0, 1]",There is an Earth energy budget. The input of energy are the Sun irradiance and the internal energy provided by the molten core. Some of the energy of the Sun is immediately reflected off the surface (via the albedo coefficient) and another output is the black body radiation of the Earth that peaks in the IR.,True,a59daf71-d948-4d60-b7a4-ace8e86205b3
The exterior of a satellite must be covered with a coating. What would be the best choice such that the temperature of the satellite is the lowest possible?,"['Gold (alpha = 0.299, epsilon = 0.023)', 'White Epoxy (alpha = 0.248, epsilon = 0.924)', 'Titanium (alpha = 0.448, epsilon = 0.129)', 'Aluminum (alpha = 0.379, epsilon = 0.0346)']","[0, 1, 0, 0]","The best coating is the one that has the lowest alpha/epsilon ratio, because alpha describes the ability of the material to absorb heat while epsilon describes the capacity to radiate heat away. Among the proposed materials white epoxy is the best choice here. It has an alpha/epsilon ratio of about 0.27.",True,2afb1154-4608-47bd-9176-2b3503a1e8a6
"Which modulation method can have a combination of 2 bits per symbol, a code rate of 0.5 and a spectral efficiency of about 1.0","['BPSK', 'QPSK', '8-PSK', '16-PSK']","[0, 1, 0, 0]",,True,caf7a503-ce34-4d2e-a11a-a8eec2b04dbc
Which of the following statements are true about Precipitation Losses for Communication Link Analysis?,"['precipitation losses attenuates RF signals by absorption', 'precipitation losses attenuates RF signals by scattering (depolarization)', 'Geographic databases of rainfall are needed for link analysis', 'precipitation losses are inversely proportional to the humidity in the atmosphere']","[1, 1, 1, 0]","Precipitation in the form of rain and wet snow attenuates RF signals through both absorption and scattering (depolarization). Precipitation-induced losses are dependent upon the product of a rate-dependent attenuation coefficient and the path length that the RF signals are required to traverse through rainfall regions within the atmosphere. Because losses are a function of the concentration of water in the atmosphere, precipitation-induced losses are heavily dependent upon a geographic and seasonal variation in weather. To provide a means for predicting rain precipitation effects, the ITU has created a geographic database of rainfall rates. This helps for link analysis.",True,61719260-46e9-444f-875e-8ea04e07f2bf
Which of the following influence the total power at the receive amplifier in communication link analyses?,"['EIRP, the Equivalent Isotropic Radiated Power', 'mu, the Standard gravitational parameter', 'Ls, the Free-Space Losses', 'Lin, the input losses to the receiver', 'Ltx, the transmitter pointing losses', 'Na, the avogadro number']","[1, 0, 1, 1, 1, 0]","The total power at the receive amplifier can be expressed as C = EIRP + Gr - Ls - Latm - Lprec - Lin - Ltx - Lrx where EIRP is the Equivalent Isotropic Radiated Power, Gr is the gain of the receive antenna, Ls are the free-space losses, Latm and Lprec are the losses due to the atmosphere and precipitation, Lin the input losses to the receiver, Ltx the transmitter pointing losses, and Lrx the depointing losses of the receiver. The standard gravitational parameter has to do with orbital mechanics but not with communication link analysis and the avogadro number is used in chemistry, not in this context.",True,8a4c5031-a489-4d16-95b6-1049aa4806a3
In spacecraft link analysis which is the name used to refer to the signal transmitted from end users (for instance military troops) to the satellite?,"['Forward uplink', 'Forward downlink', 'Return downlink', 'Return uplink']","[0, 0, 0, 1]","Forward communications links carry information toward user terminals, while return communications links carry information away from user terminals. Both forward and return links include uplinks and downlinks",True,2af4081d-5cf9-4a96-8177-f47711c45929
"What does an engineer means when she say that ""the link closes"" in communication link analysis?","['The communication is finished and there are no more signal passing through the communication chain', 'The difference between the power-to-noise ratio and the detection threshold is positive', 'The difference between the power-to-noise ratio and the detection threshold is negative', ""The energy received by the receiving antenna is strictly equal to the emitted energy (outputting the emitter's amplifier)"", 'The link margin is negative']","[0, 1, 0, 0, 0]","The difference between the power-to-noise ratio and tabulated detection thresholds refer to a parameter called the link margin. When the link margin is positive, the received signal can be detected, and the link is said to ""close"". When it is negative however the signal cannot be detected and the link does not close.",True,a82da0e7-861e-420a-9cec-97be967adbc0
Which satellite band in the electromagnetic spectrum correspond to the highest frequencies?,"['C-band', 'V-band', 'Ka-band', 'Q-band']","[0, 1, 0, 0]","V-band, mostly used for inter-satellite links uses frequency between 40 GHz and 75 GHz, then Q-band (30-40 GHz), then are Ka-band (18 to 30 GHz). C-band are of much lower frequencies, in the range of 4 to 7 GHz.",True,2e40b8b7-9830-4de0-b220-d77ad8c90abf
Which of the following satellite band is associated with its correct frequency range?,"['Ka-band (18 to 30 GHz)', 'Ku-band (11 to 18 GHz)', 'S-band (7 to 11 GHz)', 'C-band (4 to 7 GHz)', 'Q-band (2 to 4 GHz)', 'V-band (1 to 2 Gz)']","[1, 1, 0, 1, 0, 0]","S-band frequencies are within 2 to 4 GHz, Q-band frequencies are within 30 to 40 GHz (much higher than those reported), and V-band are even higher frequencies, above 40 GHz. It is L-band which correspond to frequencies between 1 and 2 GHz.",True,e55ec36c-b9b5-45fe-8136-5d52273b54bd
True or False: an electromagnetic wave to that is RHCP means it is right-handed circular polarised and the electric field vector rotates anticlockwise as viewed from the direction of propagation?,"['True', 'False']","[0, 1]",It False because RHCP means it is right-handed circular polarised and the electric field vector rotates clockwise (not anticlockwise) as viewed from the direction of propagation.,True,c2afbc6a-6128-49e9-b339-1ed9933da5a0
Why are Decibels used for communication links analyses?,"['In hommage of George Mikari Decibels, the inventor of the mechanical speaker', 'This is a standard introduced by German scientist in Huntsville, Alabama, during Rocket Engine Fire test and was kept for legacy purpose and now introduced in the ECSS', 'Because link analyses involves calculations with numbers that may differ by many orders of magnitude, decibel is simpler, faster and less error-prone.', 'Because of Aristote']","[0, 0, 1, 0]",,True,c41b75d1-8c13-49d1-ab68-ddf74eb73d52
What is the decibel equivalent of a 135 W amplifier output power relative to a 1 W reference?,"['16.0', '18.2', '21.3', '23.4']","[0, 0, 1, 0]",The power in Decibels is given by P(dB) = 10 * LOG10( P / Pref ) = 10 * LOG10( 135 / 1 ) = 21.3,True,7aec6699-a608-4ed4-8140-446f0d5117dd
How do you express the antenna gain G as a function of the antenna directivity D and various losses L?,"['G = D / L', 'G = D^2 / L', 'G = (D - L) / L', 'G = D - L']","[0, 0, 0, 1]","The total amplification factor of an antenna is given by its gain G, a value that includes both the focusing effect of the antenna (directivity D), which is a mesure of the antenna's ability to concentrate energy in a given direction, and various losses (including ohmic transmission-line losses, L for example). The formula is G = D - L",True,d1553f22-46fe-4dd8-9c35-a1df88727d49
What does A refer to in the formula G = etha * (4*pi / lambda^2 ) * A for communication link analyses,"['A relates to the absorptivity of the emitting medium (dimensionless)', 'A relates to the physical size of the antenna aperture (m^2)', 'A to the antenna volume (m^3)']","[0, 1, 0]",,True,604dfbb9-035f-4144-968e-4fc8259362e6
"How do you compute theta (in degrees), the half-power beamwidth in link analyses?","['You cannot, you need to measure it', 'Theta = frequency / Diameter', 'Theta = - k*frequency, k is a tablulated constant', 'Theta = 21 / (frequency * Diameter)']","[0, 0, 0, 1]",,True,883be593-9c9c-4437-a718-a0699882cc4c
Which is a major contribution to the antenna pointing error on-board satellite?,"['thermal distortions', 'atmospheric residual drag', 'fixed misalignment']","[1, 0, 0]","Atmospheric drag is negligible and fixed misalignment is usually mitigated on-ground and static. However, a source for variable pointing error is related to thermal distortion that results from variable heating of different antenna and spacecraft structures, changing with as the orientation of the satellite and its antennas changes with respect to the Sun, Earth, and other satellite structures like solar panels and other antennas?",True,b774f04e-e3a3-43a1-ab0b-d9bf87639636
What does typical design allow for maximum satellite antennas pointing errors?,"['Usually up to 50% of the beamwidth because it is sized to account for that loss', 'Usually around 10% of the beamwidth, so 0.1 degree for 1 degree beamwidth', 'Usually maximum 1% of the beamwidth, because beyond 1% the power-to-noise ratio decays exponentially minus infinity']","[0, 1, 0]",,True,d7b25114-55fc-4143-bb47-9196a2a31f46
Who is not a European Astronaut?,"['Thomas Pesquet', 'Christina Koch', 'Jeremy Hansen', 'Samantha Cristoforetti']","[0, 1, 1, 0]",,True,7b251f74-511d-4057-8ed3-decd500f6bb6
What is the key difference between a jet engine and a liquid rocket engine?,"['The jet engine is in general more expensive', 'The liquid rocket engine has to carry the oxidizer', 'The jet engine produce a long flamme tail after combustion']","[0, 1, 0]","The difference between a jet engine and a rocket engine, the jet engine only needs to carry its own fuel. A rocket, on the other hand, has to carry not only its own fuel but also the oxidizer, which in most cases is oxygen, either a compressed gas or liquid oxygen.",True,ae4e517f-c4a6-440c-98ff-c3d8d11faf09
"How do satellite communication missions usually cover irregular areas such as the United States, without providing bandwidth to unwanted areas (oceans, prohibited areas)?","['Increasing satellite altitude', 'Utilising higher frequency bands', 'Encrypting the signal', 'Using shaped beam reflector antennas']","[0, 0, 0, 1]","Increasing the altitude would actually broaden the signal. Higher frequency bandas can offer more focused beams, but don't inherently prevent signal spill-over into unwanted areas. The key is the shape and direction of the beam, not the frequency. Finally, encrypting the signal does not prevent it from being broadcast over unwanted area, it only controls who can access the content of the signal.",True,c2a98060-6a75-4353-9d4a-2e157218c1d0
Assuming that D_ideal is the ideal antenna maximum directivity and A_theta is the coverage area in deg^2: Which of the following is a valid formula expressing the maximum directivity achievable for an ideal antenna that covers a small solid angle?,"['D_ideal = 10 * log (A_theta)', 'D_ideal = exp(-A_theta)', 'D_ideal = A_theta / log(A_theta)', 'D_ideal = 46.15 - 10 * log(A_theta)']","[0, 0, 0, 1]",This provides a first level approximation for the link equation.,True,2a970ab4-5fd5-4e03-8e66-abaa2094b2cf
"In space communication link analyses, the ideal directivity calculations do not include antenna radiated efficiency, which is a measure of the power being radiated outside of the desired coverage area. What is the typical range of antenna efficiencies to adjust the ideal directivity?","['20 to 40%', '55 to 75%', '80 to 99%', '98 to 99.5%']","[0, 1, 0, 0]",,True,33c67e43-0041-4b8f-b867-37165c71c612
"For ground or satellite antennas, which of the following are typical contributing components to the noise temperature?","[""noise temperature that originates from the thermally radiated energy of objects that appear within the antenna's field of view"", 'noise temperature that originates from the temperature of the antenna feed structure and transmission losses within the antenna and feed assembly itself', 'noise temperature that originates high energy ionizing particles deposited energy hitting the antenna structure', 'noise temperature that originates from the delta-phi (smalled boresight angle possible) product with the Earth reflected magnetic field when crossing of the south atlantic anomaly (SAA)']","[1, 1, 0, 0]","noise temperature that originates high energy ionising particles deposited energy hitting the antenna structure is negligible and the following ""noise temperature that originates from the delta-phi (smallest bore-sight angle possible) product with the Earth reflected magnetic field when crossing of the South Atlantic Anomaly (SAA)"" is not a concept used or reference in space mission engineering.",True,c41bef86-8e11-4f1d-a082-abbcecf64bd4
What are realistic mission objectives for a missions to Mars?,"['ISRU Technology Demonstration', ""Geological and topological study to understand the historical Mars-Earth collision which led to the creation of Earth's Moon."", 'Oild fields scoutting for future super tanker missions', 'Search for scientific evidence for past life on Mars']","[1, 0, 0, 1]",,True,815136a9-3969-44c6-87d5-8bcea3f9517c
How long would a typical human crewed mission to Mars last (only the duration of the trip to reach Mars) for conjunction-type missions?,"['3 to 4 months', '6 to 9 months', '3 to 4 years', 'more than 7 years']","[0, 1, 0, 0]",,True,cc48db84-1b81-4670-a195-076dee267592
How are the two types chemical compounds of bipropellant propulsion systems called?,"['Igniter and fuel', 'igniter and oxidizer', 'fuel and oxidizer']","[0, 0, 1]",,True,73bf0237-afac-4dd9-a330-d8fcb3580379
"Which of the following rocket engine(s) is / were manufactured by ""Aerojet"" ?","['MONARC-445', 'MR-111C', 'CHT-20']","[0, 1, 0]",The MR-111C is a flight proven monopropellant hydrazine thruster.,True,64fc0fa7-43af-41d6-b8c4-268ba0c928c8
"Having stages in space launchers is advantageous because it disposes the the mass of the expended stage (tank, engine, etc...). But are there single stage launchers that are operational as of today in 2024 capable of launching a payload to Low Earth Orbit?","['Yes', 'No']","[0, 1]",,True,41456ac5-fe9b-4178-9e48-70deaca2a5b1
Select all the combinations of propulsion system and applications that are typical among the following?,"['Cold Gas propulsion for orbit insertion', 'Solid propulsion for orbit insertion', 'Liquid monopropellant for orbit insertion', 'Liquid monopropellant for attitude control', 'Electric propulsion for orbit maintenance and maneuvering', 'Liquid bipropellant for orbit insertion']","[0, 1, 0, 1, 1, 1]",,True,ea7c422b-60f6-4178-9732-0d615939c26f
What is the typical range of specific impulse for liquid monopropellant systems?,"['45 - 75s', '200 - 235s', '274 - 467s', '500 - 3000s']","[0, 1, 0, 0]",,True,3f9f6c75-740b-4c5f-a010-231506efad98
Select all the advantages of monopropellant hydrazine propulsion systems over bipropellants propulsion systems?,"['system simplicity', 'long term storability', 'capability to restart', 'higher specific impulse', 'lower toxicity']","[1, 1, 1, 0, 0]","Hydrazine monopropellant systems have lower Isp (max 230s) not higher than most bipropellants systems. Also hydrazine toxicity poses several challenges, and research is being conducted to find alternatives which are safer to handle.",True,beefd301-4e93-4e57-923b-3d992f6e8030
How does the combustion takes place for hydrazine monoprop system?,"['Hydrazine ignites spontaneous in contact of an hydrogen isotope, typically deuterium', 'Hydrazine decomposes on a micro-fluidic chip, typically made of palladium enriched carbon nanotubes in a sillicon wafer', 'Hydrazine ignites spontaneous in presence of an high-voltage electric discharge, typically 20,000 - 30,000 Volts', 'Hydrazine decomposes on a catalyst material, typically iridium']","[0, 0, 0, 1]",,True,2870f350-5488-40da-bd0c-e026b991b01f
"What is the name of the nozzle cooling technique, sometimes using in expander cycles, where one of the propellant (usually the fuel but not always) passes around the nozzle to cool it?","['Regenerative cooling', 'Ablative cooling', 'Film cooling']","[1, 0, 0]",,True,1a348c80-de10-43bc-ba82-d74ad7fd1f69
What does ablative cooling in rocket engine propulsion systems refer to?,"['chamber walls made of ablative material which decomposes into gas when heat up, hence acting as a coolant', 'combustion-generated heat is conducted through the chamber walls and rejected through radiation', 'the heat is absorbed by a thin film coating made of ablatium']","[1, 0, 0]",,True,ebd8e218-ba8f-482c-b7e1-6ee1eb7c92ec
What does AOCS usually refer to in Astronautics?,"['Astronomical Observation and Calculation System', 'Advanced Orbital Communication Satellite', 'Aerodynamic Optimization for Crew Safety', 'Attitude and Orbit Control System']","[0, 0, 0, 1]",,True,19af499b-7a42-4a72-b393-e63bb4fd6e5c
Which axis of the coordinate system for the ISS AOCS is used in the direction of the velocity vector?,"['+X (roll)', '+X (pitch)', '+X (yaw)', '-X (roll)', '-X (pitch)', '-X (yaw)']","[0, 0, 0, 0, 0, 0]",The choice of the ISS fixed coordinate system is pretty much like in aviation where we have the forward portion of ISS oriented toward the velocity vector and that's a + X axis. X is also correspond to the roll.,True,07b3bd15-13d5-45ad-b0cc-9a64d5214561
"In the LVLH coordinate system that is often used for AOCS, what is the direction of each axis ofr a spacecraft on orbit around the Earth?","['X towards the center of the Earth, Y towards the rear of the spacecraft, Z towards the north of the orbit', 'X towards the Noth of the orbit, Y towards the center of the Earth, Z towards the spacecraft velocity vector', 'X towards the spacecraft velocity vector, Y towards the south of the orbit, Z towards the center of the Earth']","[0, 0, 1]",,True,70710915-a079-49fd-874a-28d9470489ea
"ISS and Space Shuttle euler sequence was Pitch, Yaw, Roll. This is difference from most spacecraft. Which Euler sequence do spacecrafts in general?","['Yaw Roll Pitch (YRP)', 'Yaw Pitch Roll (YPR)', 'Roll Pitch Yaw (RPY)', 'Roll Yaw Pitch (RYP)']","[0, 1, 0, 0]",,True,e904a2e2-67c6-4da6-820e-1861b040d617
How it is possible to maintain a certain orientation by spinning a spacecraft?,"['Due to the electron spin', 'Due to the gyroscopic effect', 'Due to the rotational speed being waved']","[0, 1, 0]",,True,c2bd96c1-08db-4bb3-bdc0-67097d6f174c
How is it possible to use gravity gradient for attitude control?,"['For an elongated object, the gravity force at the bottom of the object is greater than the force at the top', 'For an elongated object, the gravity force at the top of the object is greater than the force at the bottom', 'For a spherical rotating object, the gravity at the bottom of the sphere is greater than the gravity at the top', 'For a spherical rotating object, the gravity gradient originates from the fluid forces momentum in the intern structure.']","[1, 0, 0, 0]",,True,b185c125-a603-4e68-97bf-796ee0dd929a
Which of the following is the primary factor determine the voltage of a solar array?,"['The temperature of the environment where the solar array is in', 'The solar cell thickness', 'The number of cells connected in series to form a string', 'The mounting structure of the solar cell']","[0, 0, 1, 0]",,True,57f57993-5f84-46b7-82ab-37aba7f12d70
Which of the following time point is used to size a satellite photovoltaic system?,"['Beginning-of-life power requirements', 'Average life power requirements plus a 10 to 20 margin', 'End-of-life power requirements']","[0, 0, 1]","This is because power requirement have to be met, even at end-of-life otherwise the satellite would not be able to operate nominally at towards the end of its mission. This results in the system often being oversized for BOL requirements and can cause power problems if not taken care of.",True,ca57a7ff-3145-4c26-ad77-1e8b1ce2fcb1
Which of the following are the lower costs cells that could be in use for satellite solar arrays?,"['Thin film amorphous Silicon cells', 'Gallium-Arsenide Triple Junction cells', 'Indium Phosphide cells']","[1, 0, 0]",,True,848d888b-d844-46ad-a5db-7b9fbaf9cb93
Which of the following rechargeable battery technologies used for satellite has the higher energy density?,"['Li-ion', 'Ni-Cd', 'Ni-H2']","[1, 0, 0]","Ni-Cd has about 30 Wh/kg, Ni-H2 has about 60 Wh/kg and Li-ion more than 125 Wh/kg energy storage density",True,f84011f6-edb0-4748-ba0d-c5a01d1bee78
"Assuming a similar lifetime, and temperature maintained range, which of the following orbit would enable to use secondary batteries with a higher depth of discharge?","['Low-Earth Equatorial Orbit mission', 'Sun-Synchronous Polar Orbit mission', 'Geostationary Orbit mission']","[0, 0, 1]","Geostationary satellite experience less frequent eclipse than Low-Earth orbiting missing, reducing the number of charge/discharge cycle on the batteries. Relaxing the number of charge/discharge requirement enables usually to increase the depth-of-discharge.",True,4efab579-4b0a-4647-9dff-4aaaf6f12713
Which of the following are typical ranges of load input power requirements in satellite engineering?,"['Normal Steady State Voltage Range: 5 to 7 V DC', 'Normal Steady State Voltage Range: 25 to 21 V DC', 'Normal Steady State Voltage Range: 150 to 220 V DC', 'Max Current 60 Amp', 'Nominal Ripple 1 V peak to peak']","[0, 1, 0, 0, 1]",Typical max current is often around 15 Amp (even though not always!),True,a95ff8d7-d775-4602-a2b9-52aa613af262
Which are the most common power bus control techniques used in satellite electrical power subsystems?,"['Alternating Current Frequency Adjustment (ACFA)', 'Voltage Multiplication Regulation (VMR)', 'Capacitive Load Stabilization (CLS)', 'Direct Energy Transfer (DET)', 'Peak Power Tracker (PPT)']","[0, 0, 0, 1, 1]",,True,7bff3a67-9181-48dd-811b-48ca49851e30
Which of the following buck-boost derived regulator is the most complex among the following?,"['Full Bridge Regulator', 'Flyback', 'Two-switch Forward']","[1, 0, 0]","From least complex to most complex are the flyback, single switch forward, two switch forward, push-pull, and full-bridge regulators",True,ea3c5ee5-1439-4e00-9555-026fc3c8837f
Which technique used on spacecraft power regulators (buck-boost) enables to further enhance their efficiency?,"['Resonant Mode Switching', 'Continuous Current Calibration', 'Voltage Ripple Reduction']","[1, 0, 0]",,True,dda35b83-c23f-4682-b89c-b4d217366785
Which of the following power source in spacecraft design usually require storage in case of Eclipse?,"['Fuell cells', 'Nuclear reactor', 'Radioistope Thermoelectric Generator', 'Solar Thermal Dynamic', 'Solar Photovoltaic']","[0, 0, 0, 1, 1]",Both solar thermal dynamic and solar photovoltaic do not generate power during eclipse so storage is require to keep the satellite powered on.,True,8d14f358-de2e-46fa-8eb2-26edb2eee900
Which of these statements are true of solid rockets?,"['They are relatively simple to build and operate', 'They provide limited ability to control thrust', 'They inherently produce more thrust than liquid rockets', 'They generate a lot of noise and vibration']","[1, 1, 0, 1]",,True,6a41ebbc-8a34-4036-a1b0-8507b0164ac1
Which of these statements are true of liquid rockets? Tell all that apply.,"['They inherently produce less thrust than solid rockets', 'They must store the oxidizer and fuel propellant components onboard in separate compartments', 'To get high performance, they must use turbo pumps to direct the propellant into the combustion chamber', 'They encounter high temperatures and pressures during combustion']","[0, 1, 1, 1]",,True,10f3799c-63b3-4154-af37-bb371b1fee35
"When applying the idea rocket equation, which components usually comprise the the rocket initial mass ?","['Payload', 'Propellant', 'Structure']","[1, 1, 1]","The initial mass at launch consists of payload, propellant, and rocket structure. The final mass refers to when the propellant has been consumed, and thus consists of payload and structure.",True,195bc8ba-e67d-435d-b384-7d23ecc1e3c8
"When applying the idea rocket equation, which components usually comprise the the rocket final mass ?","['Payload', 'Propellant', 'Structure']","[1, 0, 1]","The initial mass at launch consists of payload, propellant, and rocket structure. The final mass refers to when the propellant has been consumed, and thus consists of payload and structure.",True,85b1737f-ce24-40eb-9cac-71220489ded7
"Consider a rocket in free space having two engines with identical Isp, connected to a single propellant system. Recall that the relationship between specific impulse and exhaust velocity is  Vexhaust  = go * Isp.
If one engine fails, what is the impact on the total  ΔV  that can be obtained from the system?","['ΔV will double', 'ΔV will be cut in half', 'ΔV will stay the same']","[0, 0, 1]","If one engine fails, there is no change in specific impulse, or in the total amount of propellant available. Therefore, the total ΔV that is obtainable from the system is the same. However, the thrust is cut in half, so it will take twice as long to achieve the same ΔV (until the propellant is consumed).",True,9c2d1b44-c462-4db4-9664-7625b8b054c6
"Consider a rocket carrying 100,000 kg of propellant, 10,000 kg of structure and 5,000 kg of payload. What is the structure fraction of this rocket?","['0.053', '0.075', '0.087', '0.019']","[0, 0, 1, 0]","The structure fraction is given by the ration of the mass of the structure (10,000 kg) divided by the sum of the structure, payload and propellant (100,000 + 10,000 + 5,000). The result is 10,000 / 115,000 which is approximately 0.087.",True,655147dd-fc22-4c82-a964-a234ef65c2b7
"Consider a rocket carrying 100,000 kg of propellant, 10,000 kg of structure and 5,000 kg of payload. Using the ideal rocket equation, and assuming a specific impulse of 450s, what would be value of the Delta V in m/s that this rocket would be able to produce if all the propellant is consumed in one stage?","['8991 m/s', '9991 m/s', '10991 m/s', '11991 m/s', '12991 m/s']","[1, 0, 0, 0, 0]","The ideal rocket equation gives ΔV = g0 * Isp * ln(mass_initial / mass_final).
g0 = 9.81 m/s^2
Isp = 450 s
We need to compute the initial mass of the rocket and the final mass of the rocket.

1. Initial mass of the rocket:
initial_mass = payload_mass + structure_mass + propellant_mass = 5,000 + 10,000 + 100,000 = 115,000 kg.

2. Final mass of the rocket (everything except the propellant that has been burnt)
final_mass = payload_mass + structure_mass = 5,000 + 10,000 = 15,000 kg

ΔV = 9.81 * 450 * ln( 115,000 / 15,000) = 8991 m/s",True,830a0d7a-0ce6-4c92-9a65-e7599ac1b700
What would be the Delta V in m/s of the first stage of a rocket under the following conditions?,"['1519', '2519', '3519', '4519', '5519']","[0, 1, 0, 0, 0]","The ideal rocket equation gives ΔV = g0 * Isp * ln(mass_initial / mass_final).
g0 = 9.81 m/s^2
Isp = 450 s
We need to compute the initial mass of the rocket and the final mass of the rocket.

1. Initial mass of the rocket before the first stage has brunt (all the propellant is remaining)
initial_mass = payload_mass + structure_mass + propellant_mass = 5,000 + 10,000 + 100,000 = 115,000 kg.

2. Final mass of the rocket after first stage burnt (everything is included except the half of the propellant that has been burnt)
final_mass = payload_mass + structure_mass = 5,000 + 10,000  + 100,000/2 = 65,000 kg

 ΔV = g0 * Isp * ln(115,000 / 65,000) = 2519 m/s",True,3cd7b8d6-030b-491f-a92a-85afac24d921
"What Delta V can be achieve by the second stage of a rocket, after first stage has been jettisoned and under the following assumptions?","['6910 m/s', '7910 m/s', '8910 m/s', '9910 m/s']","[0, 1, 0, 0]",,True,493d3084-22a2-475c-8227-aeba4bae1c27
What does ECLSS refer to in astronautics?,"['Engineering Calibration and Logistics Support Services', 'Extra-terrestrial Colonization and Landing Systems', 'Electrical Circuitry and Load Support Systems', 'Environmental Control and Life Support System']","[0, 0, 0, 1]",,True,e9c6d3d7-c413-49b8-9877-4f95294d4b70
"Which of the following environmental control requirements are in general specific to human spaceflight, hence not applicable to unmanned satellite missions?","['Atmospheric Pressure Control', 'Temperature Control', 'Waste Disposal', 'Water and Food']","[1, 0, 1, 1]",,True,326efd57-822c-45e9-a16e-707e7389f102
Which of the following is true about ECLSS Closed Loop System in comparison to Open-Loop ECLSS?,"['They are reliable because there are a few moving parts', 'Resource scale linearly with flight duration', 'They require less resupply', 'They are more complex and more expensive', 'Recycling equipment can increase the launch mass']","[0, 0, 1, 1, 1]",,True,e1058454-feef-4ace-9213-a4ebdffc01ca
What is the primary driver to choose between a closed-loop or an open-loop ECLSS?,"['Spacecraft Size', 'Crew Size', 'Mission Duration', 'Launcher reliability']","[0, 0, 1, 0]","Due to the additional mass from recycling equipement, open-loop ECLSS are more interesting for short-term missions. There is a crossover point in the mission duration after which the initial investment of bringing with you recycling equipment becomes more interesting (in terms of total mass) due to the recycled matter.",True,c90f0fdc-9909-403e-892b-5e0e24bfcd1c
Which of the following recycling is represent the more mass savings using a closed loop ECLSS?,"['Food production from wastes', 'Oxygen recovery from CO2', 'Water recycling', 'Leaks prevention']","[0, 0, 1, 0]",Recycling water is by far the most important source of mass saving,True,74a14b36-92c8-4971-b30e-7beaf23cb073
Which of the following are the most import source of water consumption on-board ISS missions?,"['Drinking water', 'Food preparation water', 'Clothes wash water']","[1, 0, 0]",Clothes are not washed onboard the ISS otherwise it would consume too much water. Food preparation water is usually half of drinking water requirements.,True,ae4ace16-3c61-48db-8670-78a4d51ee9da
"Assuming there are 3 sources of independent errors on the knowledge of the volume of a given reservoir. These independent errors are 0.1 L, 0.2 L and 0.5 L. Which is the combined errors of these 3 sources of errors?","['0.30 L', '0.50 L', '0.55 L', '0.80 L']","[0, 0, 1, 0]",If the errors are independent the combined error is given by the square root of the sum of individual error squared. sqrt(0.1ˆ2 + 0.2ˆ2 + 0.5ˆ2) = 0.547. L,True,b3098ceb-1287-4387-a56b-399b5a34ca53
"What is the formula used to combined errors (e1, e2, e3) which are depend from each other? Assume that all errors are given in absolute values.","['error = e1 + e2 + e3', 'error = e1ˆ2 + e2ˆ2 + e3ˆ2', 'error = max(e1, e2, e3)', 'error = sqrt(e1 + e2 + e3)', 'error = sqrt(e1ˆ2 + e2ˆ2 + e3ˆ2)']","[1, 0, 0, 0, 0]",,True,09f6c3fa-76f5-4d6b-97f0-aab965ae525b
How do you usually compute a risk score in aerospace risk management?,"['Division of severity by probability of occurrence', 'Summation of individual risk severity', 'Average probability of occurrence of all risks', 'Multiplication of probability of occurrence by risk']","[0, 0, 0, 1]",,True,b9ccd97e-47bc-4acd-979b-85027aefc4ec
What is usually true when talking about spacecraft active redundancy systems?,"['Often used in non-critical application', 'Often used in critical application', 'Suitable for digital systems but not for mechanical systems', 'Requires manual switching to backup components upon failure', 'No action is needed to ensure the service continuity after the failure']","[0, 1, 0, 0, 1]",,True,223e2e5e-34c6-4d14-9158-2122edc90d01
What are trade trees in astronautics?,"['A catalog of spacecraft components traded on international markets', 'A new class algorithms for optimizing fuel consumption during space missions', 'Mathematical models for predicting the trajectory of celestial bodies', 'A hierarchical decomposition of decisions to make the most important decisions first']","[0, 0, 0, 1]",,True,5b7a8008-b65d-44c0-99c8-7acb5ac6a59d
Which of the following best describe push broom scanning technique for electro-optical instruments?,"['Scanning a single detector element on the ground in the cross-track direction', 'Scanning covering a full swath width using a linear arrangement of detector elements', 'Scanning using a 2-dimensional array of detector element']","[0, 1, 0]",,True,4cea1cab-95b0-430e-91c3-13a4a67ba123
True of false: Active RF systems can be used in satellite observation payload to observe emission of the highest energy photons from astrophysical objects (including Sun and supernovae)?,"['True', 'False']","[0, 1]","False because, the capability to observe emission of the highest energy photons from astrophysical objects (including Sun and supernovae) is usually provided by gamma ray payloads while active RF system like radars and synthetic aperture radars (SARs) are used for RF imagery of precipitation in clouds, surface wakes on the ocean and detailed topography of Earth and other planetary solid surfaces.",True,81c196de-f705-44da-875d-10df8dc84c1b
Which of the following was the first known SAR in space?,"['CALIPSO', 'ICESAT', 'SEASAT', 'TRMM']","[0, 0, 1, 0]",SEASAT launched in 1978 is the first known SAR in space and operated in L-band .,True,a7800b29-9996-40ff-9b1f-f6a35588d522
Which of the following aberrations can be fully corrected by Doublet/Schmidt optical systems?,"['Lateral Chromatic', 'Length Chromatic', 'Astigmatism', 'Curvature of Field', 'Spherical']","[1, 1, 0, 0, 1]",,True,1e3d4af8-4eaf-4730-8155-fb1a9cab4ecf
Which of the following reflective optical system is analogous to the Tele-optic refractive optical system?,"['Lens Doublet', 'Schmidt', 'Cassegrain', 'TMA (Three-mirror anastigmatic)']","[0, 0, 1, 0]",,True,c68460d2-8cd8-4f88-a407-6cc47d3af00d
Which of the following best describe a spherical aberration?,"[""when a sharp image is formed on a focal surface which isn't flat"", 'when light from the periphery of a spherical lens or mirror is focused nearer the element than light from the center', 'when an otherwise sharp image is distorted in shape, such as when straight light on the surface being viewed appear curved on the focal plane', 'dispersion of the light due to the refractive index of a lens being a function of the wavelength']","[0, 1, 0, 0]",,True,881245b2-6dfa-4b39-93fa-454b10919ef7
"Assuming you are calculating parameters for a passive optical sensor, what would be the sensor dynamic range DR (with respect to cold space) assuming that the number of photocarriers available Ne = 7.3e6 (evaluated for an ideal detector) and number of read-out noise electrons is Nr = 5000?","['DR = Neˆ2 / Nr = 1.07e10', 'DR = Ne / Nr = 1460', 'DR = sqrt(Ne) / Nr = 0.54']","[0, 1, 0]",,True,6a6dcec7-6109-4832-8981-f221e2f9e28e
Which type of satellite sensor should you select for you AOCS if you need an accuracy of 0.1 deg and have string mass constraint?,"['Sun Sensor', 'Star Sensor', 'Magnetometer']","[1, 0, 0]",Sun sensors have a typical accuracy of 0.005 def to 3 deg with mass varying from 0.1 to 2 kg which is accurate but weight less than star sensors. Magnetometers are not accurate enough for this performance requirements,True,b5555ff7-242f-4fe4-8734-7148627758e7
Which of the following definition is correct in the domain of spacecraft mechanisms?,"['Deployables - devices used to provide optical adjustments for space instruments', 'Drives - devices requiring continuous or frequent operation for the life of the mission where wear, lubrication and life are critical', 'Instrument mechanisms - devices generally used to create spacecraft on-orbit configurations which are larger than can be packed in the launch vehicle fairing']","[0, 1, 0]",,True,34f1d6d5-a95f-4e56-b19c-8a54a8cb5da3
What is true about MLI for satellites?,"['MLI stands for Micro Layer Insulation', 'MLI stands for Multiple Layer Insulation', 'Composed of multiples layers of low-emittance films with low conductivity', 'Composed of micrometer thickness layers of high-emittance films sandwiched with carbon fiber reinforced mesh']","[0, 1, 1, 0]",,True,8c856182-3296-4088-b56f-9be8c16eb27e
Which of the following thermal dissipation mechanism is usually not accounted for for satellite thermal balance?,"['Conduction', 'Radiation', 'Convection']","[0, 0, 1]",,True,a63a44bc-930e-4048-986e-2a2f80bf4a53
Which of the following thermal control component is used to warmup the catalyst bed of hydrazine thrusters?,"['Surface finish', 'Louvers', 'Patch heater', 'Cartridge heater', 'Grooved Heat pipe']","[0, 0, 0, 1, 0]",,True,d03a4ef0-162b-470d-969e-b7a2b75d223b
Which of the following reviews according to European Space Agency space program life cycle comes last?,"['CDR', 'MCR', 'PDR', 'SRR']","[1, 0, 0, 0]",,True,af4a6b5c-618a-4ce9-bbeb-f3c3d6252467
Select all which are commonly accepted end item verification methods?,"['Verification by inspection', 'Verification by analysis', 'Verification by test', 'Verification by similarity']","[1, 1, 1, 1]",All 4 methods are widely recognized methods of formal verification. Some users add another category of verification method: demonstration.,True,ebd7de2e-9dea-4aad-be29-3587856b4e75
What are burn-in tests for spacecraft components?,"['application of radiation stesses simulating single events', 'application of electrical stresses above normal use, or rating, usually high voltage', 'application of pseudo-random vibration spectum predicted for launch and atmospheric ascent', 'sustained high temperature operation over pre-defined time span', 'application of transients simulating those resulting from sudden release of loads (staging/separation, deployment)']","[0, 0, 0, 1, 0]",,True,828838d1-992e-412b-91ea-fe10ed216ec5
"What type of environmental tests for units under tests correspond to rapid temperature transitions between defined extremes under normal atmospheric conditions, dwelling at extremes for hours at a time?","['Pyro-shock', 'Thermal vacuum', 'Burn-in', 'Thermal cycling', 'Enhanced low dose rate sensitivity (ELDRS)']","[0, 0, 0, 1, 0]",,True,2147b0f6-662f-4872-8b8e-18e280d5e29d
How can you compute the MTBF assuming you know the failure rate lambda?,"['lambdaˆ2', 'lambdaˆ(1/2)', '1 / lambda', 'lambda / (1 - lambda)']","[0, 0, 1, 0]",,True,beb8a417-4d86-44f1-b07b-e3ba7dbf6194
"Consider a propellant feed system with two valves in series. Valve one has a probability of failure in close position of 0.01 and the other valve has a probability of failure in close position of 0.02. If any of the valve fail in the close position, the propellant cannot flow anymore. What is the overall reliability R of the feed system to still be open?","['Approximately 0.95', 'Approximately 0.97', 'Approximately 0.03', 'Approximately 0.02', 'Exactly 0.87', 'Exactly 0.76']","[0, 1, 0, 0, 0, 0]",R = (1 - 0.01)*(1-0.02) = 0.99 * 0.98 = approx. 0.97,True,0908d052-016a-410e-a96c-ab10b813b4f6
Which of the following languages will you have to learn as a minimum if your are selected as an Astronaut?,"['French', 'Chinese', 'English', 'Japanese', 'Russian']","[0, 0, 1, 0, 1]",,True,1f9fc6c5-c327-4450-80bf-270c646f093d
Which of this center are knwon for Astronaut training?,"['Jet Propulsion Laboratory', 'Kennedy Space Center', 'Johnson Space Center', 'Star City', 'ESA/ESTEC', 'ESA/EAC']","[0, 0, 1, 1, 0, 1]",,True,fba43aad-6a08-4d7a-946e-d73a65a99742
Which of the following system enable astronaut to experience up to 20 seconds of weightlessness?,"['zero-G flight', 'Drop tower', 'Centrifuges', 'Water Buoyancy Lab']","[1, 0, 0, 0]",,True,cf12aa3a-38cc-4067-b829-0510a550874e
What should you do first when a non-confirmance is detected according to the ECSS?,"['Implement corrective and preventive actions', 'Call the supplier and fire them', 'Issue a non-conformance test plan (NCTP)', 'Organize an internal non-conformance review board (NRB)', 'Issue an internal Non-conformance report (NCR)', 'Notify the customer and call out for a customer non-conformance review board (NRB)']","[0, 0, 0, 0, 1, 0]",,True,793b77a7-204e-4acc-a252-b56ed5e25263
Which of the following are commonly accepted dispositions of minor non-conformances?,"['Return to supplier', 'Use ""As Is""', 'Rework', 'Repair', 'Scrap', 'Test again until test pass']","[1, 1, 1, 1, 1, 0]",,True,7e74f9c0-2899-40b3-a143-19cd380ebdd2
What type of orbit is famous for its long dwell time over North America and Russia while passeing quickly over the southern hemisphere?,"['Geostationary Orbit', 'Polar Orbit', 'Sun Synchronous Orbit', 'Korolev Orbit', 'Molniya Orbit', 'Kennedy Orbit']","[0, 0, 0, 0, 1, 0]",,True,6e49ffae-e12f-4053-b482-0f35294b805c
Which of the following gas is the main component of the Mars atmosphere?,"['N2', 'O2', 'CO2', 'CH4', 'Ar']","[0, 0, 1, 0, 0]",Mars Atmosphere is made up to 96% of CO2,True,80f3bfa3-5198-4c0f-a137-4c679b192a58
How long do Lunar night last near the Moon equator (period of time where your solar array will not generate electricity and where you would have to run on batteries),"['3.5 hours', '35 hours', '350 hours', '3500 hours']","[0, 0, 1, 0]",,True,73f86516-6e00-4668-91e8-9e15ebb3912e
Which can you find on the Moon surface?,"['Liquid methane', 'Lava tubes', 'Ilmenite', 'Iron, Titanium, and Aluminum oxides', 'A thin atmosphere']","[0, 1, 1, 1, 0]",,True,10a3f4eb-6269-41c8-9a78-410ff0189ffb
Which mission types to Mars often include a Venus fly-by?,"['Conjunction mission', 'Cross-trapped mission', 'Opposition mission', 'S-type mission', 'J-type mission']","[0, 0, 1, 0, 0]",,True,ed958ac6-616f-479d-b73c-203016fdf5d5
Which of the following methods are well known for propellant gauging in satellite propellant subsystems?,"['Pressure-Volume-Temperature', 'Entropy-Enthalpy-Gibbs', 'Book-keeping', 'Station-keeping']","[1, 0, 1, 0]",,True,1e79fa37-6af1-4a77-9b9d-5f448a7924e4