Across
- 3. the nature of the sound
- 6. to be left in isolation
- 8. the science of flight
- 10. necessary to the maintenance of life
- 11. relating to the planet Mars or its hypothetical inhabitants
- 12. a victory
- 14. to undertake the risks and dangers
- 15. a guard that protects a spaceship from the heat of launching
Down
- 1. degree of mixture with base metals
- 2. settled on a precarious spot
- 4. an astronaut of the Soviet space program
- 5. important, or essential
- 7. first notable success
- 9. very great in size
- 13. drop from spacecraft in flight