Question

clearing out junk in space
\dont forget to take out the garbage!\ many teenagers hear this familiar parental reminder on a daily or weekly basis, depending on where they live. disposing of common household trash is a fairly simple task, but on spacecraft, astronauts must use a more sophisticated method for clearing out junk.
during u.s. space shuttle missions from 1981 to 2011, astronauts had to perform many tasks, including cleaning windows, doing dishes, and taking out the trash. once they filled their allotted waste bins, crews moved the garbage to an area separate from their living quarters. there, the trash remained until the shuttle returned to earth. to eliminate odors from decaying refuse, astronauts used a special vacuum to vent foul smells into space.
today, the international space station (iss) uses a different process for trash disposal. since astronauts reside there for up to six months at a time, a large quantity of garbage accumulates. astronauts need to avoid a smelly pile because some waste can grow microbes that pose health risks. to solve this, a garbage truck of sorts visits the spacecraft periodically. this unmanned spaceship arrives with food, equipment, and other supplies, then it is launched back to earth carrying hazardous waste like used batteries and medical supplies, as well as harmless trash—discarded food and dirty clothes. upon reaching earths atmosphere, the cargo and spacecraft incinerate. using expendable vehicles keeps manned crews safe by limiting their exposure to noxious substances, including chemical and biological waste.
one of the biggest problems with garbage in space is not the garbage itself...
davion wayne wright, id#******
which sentence best expresses the central idea of the passage?

1. spacecraft can maneuver to avoid colliding with space junk.
2. collisions in space increase the amount of junk that is in orbit.
3. reducing space junk is important to the success of future space missions.
4. astronauts use a sophisticated system to dispose of used batteries and supplies.

Explanation:

• Option 1 focuses on spacecraft avoiding space junk collisions, but the passage is about disposing of space junk, not avoiding collisions.
• Option 2 talks about collisions increasing space junk, but the passage's main focus is on disposing of space junk, not how it's increased.
• Option 3: The passage discusses methods of disposing space junk (like on shuttles and ISS) to ensure safe future space missions (avoiding health risks, etc.), so reducing space junk is important for future missions' success.
• Option 4 is too narrow as it only mentions disposing of used batteries and supplies, while the passage covers general space junk disposal.

Answer:

1. Reducing space junk is important to the success of future space missions.