Exam + Out of Scope Questions

Question 1

What is the first and second cosmic velocity and what ist their respective values or formulars?

I2S / OFM

Answer 1

1st: Lowest possible velocity around Earth (7.91 km/s or sqrt(μ/r_earth) )

2nd: Velocity to escape earth’s SOI (11.2 km/s or sqrt(2μ/r_earth) )

Question 2

What is the typical Δv that is required to reach LEO from the surface of Earth?

I2S / OFM

Answer 2

Typical value for transfer Earth-LEO is 9.5 km/s

Question 3

What is the difference between the term fuel and propellant?

I2S

Answer 3

• Propellant represents both Fuel and Oxidizer
• Fuel is a propellant component that is oxidized

Question 4

How is the Tsiolkovsky equation?

Formular

Answer 4

Δv = c_e * ln(m_o/m_f)

Question 5

What are the six orbital elements that define an orbit?

(Keplerian) (6)

I2S / OFM

Answer 5

1. semi-major axis (α)
2. eccentricity (e)
3. argument of periapsis (ω)
4. inclination (i)
5. longitude of ascending node (LAAN) (Ω)
6. True anomaly (v)

Question 6

At which point along an orbit does a manoeuvre have to take place in order to change the inclination (only)?

I2S / OFM

Answer 6

Either at the ascending node or the descending node of the orbit. Both points are at the intersection of the orbit with the reference plane.
(If not circular, at point with lower Δv)

Question 7

Name all planets from our solar system?

I2S / OFM

Answer 7

(Sun)
1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune

Mein Vater erklärt mir jeden Samstag unseren Nachthimmel

Question 8

What is the approximate orbital period of the ISS?

I2S / OFM

Answer 8

approx. 92min

Question 9

What is the approximate radius of the Earth, LEO, GEO?

OFM

Answer 9

1. Earth = 6378km (approx 6380km)
2. LEO = 6580 - 7380km (h=200-1000km)
3. GEO = 42240km (h=35860km)

Question 10

What is the height of the ISS?

I2S / OFM

Answer 10

h = 350km
r = 6730km

Question 11

What was the name of the first artificial satellite and which country launched it?

I2S

Answer 11

Sputnik 1, launched by Russia

Question 12

Which are the 2 most common staging?

I2S

Answer 12

Serial and parallel staging

Question 13

What is a SSO?

I2S

Answer 13

A SSO is a sun-synchronous orbit. It has a very high incliniation (i-98°) and a spacecraft in a SSO is always flying over the same spot on the Earth at the same local time. Therefore, if various images of the same spot on Earth are taken on different days, the shadows of any object is the same.

Question 14

What are the different types of these conical intersections and state the algebraic sign of their respective orbital energy.

I2S

Answer 14

1 > e > 0: elliptic
e = 0: circular
e = 1: parabolic
e > 1: hyperbolic

Question 15

A spacecraft is on an elliptical orbit. At which point on its orbit does it have its highest and lowest velocity?

I2S

Answer 15

Highest: Periapsis
Lowest: Apoapsis

Question 16

How does thrust and effective exhaust velocity of a rocket engine change if they are operated on sea level or in space?

I2S

Answer 16

With decreasing ambient pressure p_a, thrust F and the effective velocity c_e is increasing. Hence, thrust and c_e will be higher in space than at sea level.

Question 17

Order the following engine types according to their typical specific impulse (starting with the lowest)

I2S

Answer 17

1. Cold gas
2. Liquid propellant engines
3. Nuclear
4. Electro-static engine

Question 18

Name 3 launchers which are currently operational (have flown in the past 5 years)

I2S

Answer 18

Ariane 6, Vega, SLS, Falcon 9, Falcon Heavy, Atlas V, Vulcan Centaur, H3, Electron, Soyuz-2, Proton-M, Angara A5, GSLV, PSLV, Long March 2F, Long March 3B