
Now Playing: NASA Spacecraft Set to Explore Giant Asteroid That Could Destroy Earth
Now Playing: NASA’s OSIRIS-REx spacecraft arrives at asteroid Bennu after long journey
Now Playing: Bigger stores without cashiers may be on the way
Now Playing: NASA is looking for contractors for the next moon mission
Now Playing: Amazon faces complaints over sponsored products placed in registries
Now Playing: Facebook executives considered charging companies for user data
Now Playing: Doctor behind first genetically modified babies: ‘I feel proud’
Now Playing: How to protect your privacy when getting rid of old phones
Now Playing: Researcher in middle of gene controversy defends his work
Now Playing: Alleged bias in Google searches prompts congressional hearing
Now Playing: Are genetically-edited babies ethical?
Now Playing: Cyber Monday smashes sales records
Now Playing: Donald Trump’s trade war with China could raise the price of your iPhone
Now Playing: Getting to know Mars, the ‘red planet’
Now Playing: NASA’s Insight lander successfully touches down on Mars
Now Playing: NASA’s InSight lander touches down on Mars
Now Playing: NASA spacecraft expected to touch down on Mars
Now Playing: NASA probe to touch down on Mars today
Now Playing: Experts say this Cyber Monday could be biggest shopping day in history
Now Playing: Historic mission to Mars