TeamIndus quiz on Spacecraft Guidance, Navigation and Control

1. GNC quiz
Sample questions

2. Rules
• 3 rounds:
• Round 1: 13 x General – 2 points each
• Round 2: 8 x Anagrams- 1 point each
• Round 3: 2 x Connect questions- 4 points each

3. Identify X
“The Apollo computer used 2k
of magnetic core RAM and 36k
wire rope [...]. The CPU was built
from ICs [...]. Clock speed was
under 100 kHz [...]. The fact that
the MIT engineers were able to
pack such good software (one of
the very first applications of the
X filter) into such a tiny
computer is truly remarkable.”
— Interview with Jack Crenshaw,

4. Identify X
Rudolf Kalman (Kalman
filter)
https://en.wikipedia.org/
wiki/Rudolf_E._K%C3%A1
lm%C3%A1n

5. Identify mission
(where this guidance was used)

6. Chang’e 3
https://www.researchgate.net/publication/28434
5092_Guidance_Summary_and_Assessment_of_t
he_Chang'e-3_Powered_Descent_and_Landing

7. What are these called?

8. ‘Feelers’
http://heroicrelics.org/info/lm/lunar-surface-
probe.html

9. What is being shown in the figure below?

10. Falcon 9 booster landings

11. Name and explain this effect,

12. Sagnac effect
• Relates the change in path length to change in wavelength due to a
rotation rate

13. Identify mission?
Arrived at Moon
May 30, 1966 landed on Oceanus Procellarum
September 20, 1966 crashed near Copernicus crater
April 17, 1967 landed on Oceanus Procellarum
July 14, 1967 crashed on Sinus Medii
September 8, 1967 landed on Mare Tranquillitatis
November 7, 1967 landed on Sinus Medii
January 7, 1968 landed near Tycho crater

14. Surveyor
Arrived at Moon
July 14, 1967 crashed on Sinus Medii
September 8, 1967 landed on Mare Tranquillitatis
November 7, 1967 landed on Sinus Medii
January 7, 1968 landed near Tycho crater

15. Identify X and Y

16. X, Y= Luna 9 and
Surveyor 1

17. Connect
• Academy of Science, Saint Petersburg

18. Lyapunov
https://en.wikipedia.org/wiki/Lyapunov_function
https://en.wikipedia.org/wiki/Aleksandr_Lyapunov
• Academy of Science, Saint Petersburg

19. Identify X
• It was determined that the chain of events that led to the spacecraft's loss began
with its X. The attitude control system attempted to use Hitomi's reaction
wheels to counteract the non-existent spin, which caused the spacecraft to rotate
in the opposite direction. Because the X continued to report faulty data, the
reaction wheels began to accumulate excessive momentum, tripping the
spacecraft's computer into taking the vehicle into "safe hold" mode. Attitude
control then tried to use its thrusters to stabilise the spacecraft; the sun
sensor was unable to lock on to the Sun's position, and continued thruster firings
caused Hitomi to rotate even faster due to an incorrect software setting. Because
of this excessive rotation rate, early on 26 March several parts of the spacecraft
broke away, likely including both solar arrays and the extended optical bench.

20. X=IRU/Gyro
• It was determined that the chain of events that led to the spacecraft's loss began
with its X. The attitude control system attempted to use Hitomi's reaction
wheels to counteract the non-existent spin, which caused the spacecraft to rotate
in the opposite direction. Because the X continued to report faulty data, the
reaction wheels began to accumulate excessive momentum, tripping the
spacecraft's computer into taking the vehicle into "safe hold" mode. Attitude
control then tried to use its thrusters to stabilise the spacecraft; the sun
sensor was unable to lock on to the Sun's position, and continued thruster firings
caused Hitomi to rotate even faster due to an incorrect software setting. Because
of this excessive rotation rate, early on 26 March several parts of the spacecraft
broke away, likely including both solar arrays and the extended optical bench.
• https://en.wikipedia.org/wiki/Hitomi_(satellite)

21. Connect

22. Attitude estimation using Kalman filter
https://arc.aiaa.org/doi/10.2514/3.56190
Markley, Schuster,Kalman Filter

23. What is happening here?

24. Hayabusa touchdown
Documentary:
https://www.youtube.com/watch?v=1GWsIzU-bm0

25. Identify X
On the basis of the outcome of the investigations performed, the SIB
members identified four main root causes that led to the X failure: -
1. Insufficient conservative modelling of the parachute dynamics
which led to expect much lower dynamics than observed in flight; -
2. Inadequate persistence time of the IMU saturation flag and
inadequate handling of IMU saturation by the GNC;
3. Insufficient approach to FDIR and design robustness;
4. Mishap in management of subcontractors and acceptance of
hardware, (the persistence of IMU saturation time was not
recorded at acceptance and instead believed to be 15 ms).

26. X: Schiaparelli
On the basis of the outcome of the investigations performed, the SIB
members identified four main root causes that led to the X failure: -
Insufficient conservative modelling of the parachute dynamics which led to
expect much lower dynamics than observed in flight; - Inadequate
persistence time of the IMU saturation flag and inadequate handling of IMU
saturation by the GNC; - Insufficient approach to FDIR and design robustness;
- Mishap in management of subcontractors and acceptance of hardware,
(the persistence of IMU saturation time was not recorded at acceptance and
instead believed to be 15 ms).
http://exploration.esa.int/science-e/www/object/doc.cfm?fobjectid=59175

27. What?

28. LM Powered-flight Attitude Control

29. Anagrams

30. Anagrams: 1 word
NadaAnarchy
Hint: Mission

31. Anagrams: 1 word
Chandrayaan
Hint: Mission

32. Anagrams: 1 word
Naga Layman
Hint: Mission

33. Anagrams: 1 word
Mangalyaan
Hint: Mission

34. Anagrams: 3 word
Advantaged Anointing Councilor
Hint:

35. Anagrams: 3 word
Guidance, Navigation and Control
Hint:

36. Anagrams: 3 words
Alan Refundment Tickles

37. Anagrams: 3 words
Unscented Kalman Filter

38. Anagrams: 3 words
Adele clouding scoop

39. Anagrams: 3 words
Closed loop guidance

40. Anagrams: 1 word
can soup

41. Anagrams: 1 word
Canopus

42. Anagrams: 4 word
announcer pile reshuffle
Hint: 60, 000 km

43. Anagrams: 4 word
Lunar sphere of influence
Hint: 60, 000 km

44. Anagrams: 1 word
• Rendezvous

45. Anagrams: 2 words
Garland Indra

46. Anagrams: 2 words
Landing radar

47. Connect
https://www.vanderbilt.edu/usli/2017/01/04/imu-mishaps-plague-recent-nasa-esa-missions/

48. Connect
StereoB, Schiaparelli, Hitomi
Recent missions suspected to fail due to gyro/IMU problems
https://www.vanderbilt.edu/usli/2017/01/04/imu-mishaps-plague-recent-nasa-esa-missions/

49. Connect

50. Connect
Moon Impact probe, Shackleton Crater, Minerology discovered by
Chandrayaan mission. Evidence of water-ice on the moon.