lecture 9

Question 1

What is something that space agencies want to do with asteroids?

Answer 1

asteroid mining
- more specifically to drill past the ice on Europa and get to its surface
- we are not close to doing this
- many companies formed on the sole basis of asteroid mining

Question 2

Why do we want to mine asteroids?

Answer 2

• to retrieve precious metals that are not as common on earth for economic value (electronics)
• to retrieve helium-3 (powers the sun through the hydrogen -> helium process)

Question 3

What are the two companies that stand out the most when it comes to asteroid mining?

Answer 3

ARKYD-6
- tested how to identify best asteroids to mine; something worth the effort
- launched successfully in 2018 to demonstrate it was possible to check what mateirals the asteroids are abundant in

Astroforge
- Demonstrated (unsuccessfully) microgravity mining techniques
- 2 launched planned for 2025
- one will rendezvous with a near asteroid
- no other vehicle has communicated with electronics past LEO

Question 4

What is propulsion and why is it different in space

Answer 4

Propulsion is the fact that everything needs speed (energy) to move

space
- a lot of speed required in a short time to leave earths gravity
- the energy required to change direction can be done, but does not need to be done as quickly
- energy must be controlled; rocket is essentially a bomb, energy must be released in a controlled way (chemical, ion, solar)

Question 5

What are the 4 types of orbit?

Answer 5

• low earth orbit (LEO)
• medium earth orbit (MEO)
• geostationary orbit (GEO)
• high earth orbit (HEO)

Question 6

Name the characteristics of Low Earth Orbit

Answer 6

• easiest to reach; 2000km above surface
• telescopes, satellites
• most friction bc of atmosphere; causes satellites to eventually de orbit

Kessler syndrome/effect
- too many satellites; increases potential for collisions causing chain reactions
- increases space debris

Question 7

Name the characteristics of Medium Earth Orbit

Answer 7

• higher than LEO; 2,000 - 35,786 km
• van allen radiation belts; protects us from sun radiation
• GPS and Communication satellites use this region

Question 8

Name the characteristics of Geostationary Orbit

Answer 8

• Matches earths rotation; returns to the same location each day; E->W elliptical orbit
• sways up and down

Geostationary orbit
- appears to remain stationary from earths surface above the equator
- used by telecommunication satellites; antennas

Question 9

Name the characteristics of High Earth Orbit

Answer 9

• longer than 24 hours
• things here will never return to earth; not enough friction

Question 10

What is escape velosity (V esc)?

Answer 10

escaping earths gravitational field
- energy from rocket must be enough to escape earths velosity
- getting out of earths orbit is the hardest part bc of the weight from the fuel

formula
- V esc = √2GM / R