(CNN) -- The surviving pilot of Virgin Galactic SpaceShipTwo told authorities he was unaware the feather system had been unlocked early by his co-pilot.

The spaceship disintegrated 45,000 feet above the Mojave Desert on October 31, killing co-pilot Michael Tyner Alsbury and injuring co-pilot Peter Siebold, who managed to parachute to the ground.

Siebold was interviewed last week by the National Transportation Safety Board. He described being "extracted from the vehicle as a result of the break-up sequence and unbuckled from his seat at some point before the parachute deployed automatically," according to a release from the NTSB.

Earlier this month, the NTSB tweeted that Alsbury "moved the lock/unlock handle into unlock position."

...the copilot, who was in right seat, moved the lock/unlock handle into unlock position; he did not survive accident. #SpaceShipTwo

But that mishap alone doesn't explain why the feathering started, since no one moved the feathering handle.

During feathering, two pieces on the back of the vehicle -- the "feathers" -- lift up perpendicular to the spaceship, making the vehicle look as though it's arching its back as it descends.

The wreckage has been recovered and will be used for follow-up examinations.

Test pilot's workplace a cold, harsh environment

Answer the following questions:
1. How many feet above ground did the spaceship disintegrate?
2. Who survived the accident?
3. Who was killed?
4. When did this happen?
5. Who moved the lock/unlock handle according to the NTSB?
6. What system was unlocked?
7. What does NTSB stand for?
8. What happens during feathering?
9. Has the wreckage been found?
10. What did Siebold say deployed automatically?
11. What desert were they over?
12. Did anyone move the feathering handle?
13. What does feathering make the spaceship look like when it's coming down?
14. What was the name of the spaceship?
15. Was Siebold injured?
16. Did he break his leg?
17. What will happen with the wreckage that was found?
18. When was Siebold interviewed?
19. When did the NTSB tweet about Alsbury?
20. Who was in right seat?

Numbered answers:
1. 45,000 feet
2. Peter Siebold
3. Michael Tyner Alsbury
4. October 31
5. Alsbury
6. Feather system
7. National Transportation Safety Board
8. Two pieces on the back of the vehicle lift up
9. Yes
10. Parachute
11. Mojave Desert
12. No
13. As though it's arching its back
14. Virgin Galactic SpaceShipTwo
15. Yes
16. unknown
17. Will be used for follow-up examinations.
18. Last week
19. Earlier this month
20. Alsbury