patrickfleith/Astro-mcqa huggingface dataset:
Question: True or False? An object that is not accelerating or decelerating has no forces acting on it.
Options:
True, False, Impossible to say without more information
Answer key (one line per option, 1 = correct):
0
1
0
Justification: 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.
Question: Complete the following: During its orbital period, as a planet moves farther away from the sun, the orbital velocity of the planet ...
Options:
remains the same, increases, decreases
Answer key (one line per option, 1 = correct):
0
0
1
Question: Which affirmation is true when talking about Earth’s potential energy?
Options:
The potential energy is positive, The potential energy is constant, The potential energy is negative, None of the above answers
Answer key (one line per option, 1 = correct):
0
0
1
0
Justification: This is because the Earth potential energy is expressed as Epot = - mu / r
Question: Why do we talk about microgravity in LEO?
Options:
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
Answer key (one line per option, 1 = correct):
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1
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Question: To what wavelength is the atmosphere the most transparent?
Options:
X-rays, Visible light, Infra Red, Radio Waves
Answer key (one line per option, 1 = correct):
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0
0
1
Question: In the atmosphere and space environment, what best describes the so-called airglow?
Options:
Photo ionization of oxygen, Northern lights, Diffraction of the Sun light in the upper layers of the atmosphere, Photo Ionization of Hydrogen
Answer key (one line per option, 1 = correct):
1
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Question: 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?
Options:
thermosphere, troposphere, stratosphere, mesosphere, troposphere, mesosphere, thermosphere, stratosphere, troposphere, stratosphere, mesosphere, thermosphere, troposphere, mesosphere, stratosphere, thermosphere
Answer key (one line per option, 1 = correct):
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Question: What are the Van Allen belts?
Options:
The region between 90 and 100 km altitude, Low radiation regions, Much used orbits for telecommunication, Radiation belts
Answer key (one line per option, 1 = correct):
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0
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1
Justification: 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.
Question: Why is the inner radiation belt harmful for satellites, and more so than the outer belt ?
Options:
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.
Answer key (one line per option, 1 = correct):
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Justification: 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.
Question: The sunspot number is a value that changes with time, with a period of approximately...
Options:
7 years, 9 years, 11 years, 13 years
Answer key (one line per option, 1 = correct):
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0
1
0
Question: True or False: the latitude of sunpots during a solar cycle stays uniform and constant, regardless of the sun activity
Options:
True, False
Answer key (one line per option, 1 = correct):
0
1
Question: 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?
Options:
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
Answer key (one line per option, 1 = correct):
1
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Question: Based on your understanding of the solar cycle, where would be the best place to see auroras? (select all that apply)
Options:
Close to Antarctic and Arctic circles, Near the equator, Iceland or northern Scandinavia, Latin America
Answer key (one line per option, 1 = correct):
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Question: What would be the most appropriate time to observe auroras?
Options:
2018, 2023, anytime, 2029
Answer key (one line per option, 1 = correct):
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Question: What is the main driver of the shape of solar prominences ?
Options:
Van Allen radiation belts, Earth, Magnetic fields generated by the sun, The orbital forces of Mercury
Answer key (one line per option, 1 = correct):
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Question: What is the difference between CMEs (Coronal Mass Ejections) and prominences ?
Options:
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
Answer key (one line per option, 1 = correct):
1
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Question: What is the typical lower boundary of the Van Allen belts?
Options:
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
Answer key (one line per option, 1 = correct):
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Question: What is the global shape of the Earth radiation belts?
Options:
Spherical, Rectangular, Toroidal, Triangular
Answer key (one line per option, 1 = correct):
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Question: What is the sectional profile of the Earth radiation belts?
Options:
Banana-shaped, with the extremities away from the Earth, Banana-shaped, with the extremities close to the surface of the Earth, Rectangular, Disk
Answer key (one line per option, 1 = correct):
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1
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Question: The activity of the Sun has a periodicity of 11 years. What are the methods to observe it? (Select all that apply)
Options:
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
Answer key (one line per option, 1 = correct):
1
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Question: 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?
Options:
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
Answer key (one line per option, 1 = correct):
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Question: 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?
Options:
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
Answer key (one line per option, 1 = correct):
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Question: What is the magnetosphere?
Options:
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
Answer key (one line per option, 1 = correct):
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1
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Question: 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?
Options:
It increases, It descreases, It stays the same, Impossible to say, we need more information to answer
Answer key (one line per option, 1 = correct):
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Question: Crossing the South Atlantic Anomaly (SAA) with a satellite can greatly restrict its performance. Why?
Options:
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.
Answer key (one line per option, 1 = correct):
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Question: 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?
Options:
Object X, Object Y, Both at the same time, Impossible to say
Answer key (one line per option, 1 = correct):
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Justification: The masses and cross-sections have to be given to be able to estimate which will fall back first.
Question: 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
Options:
23 years, 24 years, 25 years, 42 years
Answer key (one line per option, 1 = correct):
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Question: Hubble's solar arrays were damaged because of collisions with:
Options:
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
Answer key (one line per option, 1 = correct):
1
1
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Question: 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?
Options:
1.72 m/s^2, 8.68 m/s^2, 0 m/s^2, 7.78 m/s^2
Answer key (one line per option, 1 = correct):
0
1
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Question: What is the escape velocity from the surface of the moon Europa (mass M = 4.8e22 kg, radius 1560 km)? (answer in km/s)
Options:
Approximately 1, Approximately 2, Approximately 3, Approximately 4, Approximately 5
Answer key (one line per option, 1 = correct):
0
1
0
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Justification: The escape velocity of Europa is simply computed from Vesc = sqrt( 2*mu / R) which is approximately 2 km/s
Question: 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?
Options:
0.2, 1.4, 2.7, 3.6, 5.4
Answer key (one line per option, 1 = correct):
0
0
0
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1
Justification: 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.
Question: 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 ?
Options:
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.
Answer key (one line per option, 1 = correct):
1
1
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Question: 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?
Options:
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.
Answer key (one line per option, 1 = correct):
0
1
0
Question: 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)
Options:
4.7, 5.0, 5.3, 5.6, 5.9
Answer key (one line per option, 1 = correct):
1
0
0
0
0
Question: 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.
Options:
g0 * R * p^2, g0 * R * p, g0 * R, g0 * R^2
Answer key (one line per option, 1 = correct):
0
0
1
0
Question: 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)?
Options:
V = mu * r
V = sqrt( 2 * mu / r^3 )
V = sqrt( mu / r )
V = sqrt( 2 * mu / r )
V = sqrt( mu / 2r )
Answer key (one line per option, 1 = correct):
0
0
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Question: 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?
Options:
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.
Answer key (one line per option, 1 = correct):
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1
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Question: 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.
Options:
Etot >= 0
Etot < 0
Etot is close to + infinity
Etot is close to - infinity
Answer key (one line per option, 1 = correct):
1
0
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Question: 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?
Options:
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.
Answer key (one line per option, 1 = correct):
1
0
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Question: What is the orbital velocity of the Hubble Space Telescope which is on a circular orbit at 555 km altitude? (answer in km/s)
Options:
4.00, 6.21, 7.58, 8.02
Answer key (one line per option, 1 = correct):
0
0
1
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Question: What is the strength of the Earth’s acceleration in LEO?
Options:
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
Answer key (one line per option, 1 = correct):
0
0
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Question: Which of the following proportionnality relation with the orbital period T with respect to the semi-major axis a is correct?
Options:
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)
Answer key (one line per option, 1 = correct):
0
0
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1
Question: 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?
Options:
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
Answer key (one line per option, 1 = correct):
1
0
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Question: 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?
Options:
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
Answer key (one line per option, 1 = correct):
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0
0
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1
Question: 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?
Options:
18.0, 89.5, 95.0, 100.9
Answer key (one line per option, 1 = correct):
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0
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0
Question: 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?
Options:
0, 1, 1.3, 0.5
Answer key (one line per option, 1 = correct):
1
0
0
0
Justification: Since the Earth's rotation is constant, the eccentricity of the orbit is zero, otherwise its orbital velocity would not be constant.
Question: 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?
Options:
7.01°, 0°, 3.2°, 45°
Answer key (one line per option, 1 = correct):
0
1
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0
Justification: The inclination is also zero otherwise the satellite's pointing would oscillate across the equator.
Question: In orbital mechanics, what is the meaning of the mean motion n = sqrt( mu / a^3 )?
Options:
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.
Answer key (one line per option, 1 = correct):
1
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Question: What reference frame is the best suited for an interplanetary probe?
Options:
Geographic coordinate system, Geo-centric coordinate system, Heliocentric-inertial coordinate system
Answer key (one line per option, 1 = correct):
0
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Justification: 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.
Question: The complete precessional cycle of the Earth lasts about 26000 years. What is the precession rate? (in degrees per year)
Options:
0.00384, 0.01384, 0.02384, 0.03384, 0.04384, 0.05384
Answer key (one line per option, 1 = correct):
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1
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0
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Justification: The precession rate per year is 360°/26000 years = 0.0138°/years.
Question: What is the RAAN?
Options:
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.
Answer key (one line per option, 1 = correct):
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Justification: 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.
Question: How long is a sideral day?
Options:
24h00min, 24h04min, 11h56min, 23h56min
Answer key (one line per option, 1 = correct):
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Justification: The sidereal day, is the time it takes for the Earth to make one full rotation with respect to the stars, 23h56'04''.
Question: Where is an orbital maneuver Delta-V adding energy to a spacecraft on orbit best performed?
Options:
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.
Answer key (one line per option, 1 = correct):
1
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Justification: 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.
Question: What is the Hohmann transfer for small Delta-V useful for?
Options:
Interplanetary trajectories
Earth-Moon transfer
Manoeuvers around small bodies (e.g. comets)
Orbital rendez-vous
Answer key (one line per option, 1 = correct):
0
0
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1
Question: Where is the Delta-V for an inclination change smaller?
Options:
at low altitudes, at high altitudes, at the equator, at the poles
Answer key (one line per option, 1 = correct):
0
1
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Justification: 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.
Question: What is the difference between geostationary and geosynchronous orbits?
Options:
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
Answer key (one line per option, 1 = correct):
0
1
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Justification: 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°
Question: 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?
Options:
12.5, 15, 17.5, 20, 22.5
Answer key (one line per option, 1 = correct):
0
0
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Justification: 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°
Question: For a circular orbit of a given inclination, at what altitude will a satellite be impacted the most by nodal regression?
Options:
200 km, 2000 km, 500 km, 12000 km
Answer key (one line per option, 1 = correct):
0
0
0
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Justification: The lower the satellite, the stronger the effects of the nodal regression.
Question: Among the following assertion about Lagrange points, which one is true?
Options:
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
Answer key (one line per option, 1 = correct):
0
0
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Justification: 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.
Question: A spacecraft is below and behind the ISS, both are on circular orbits. What will happen to their relative position?
Options:
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
Answer key (one line per option, 1 = correct):
1
0
0
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Justification: 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.