Question

to the naked eye, mars seems as distant as the stars. but humans may set foot on the red planet in the near future, according to scientists at the national aeronautics and space administration (nasa). to make it happen, nasa is pursuing creative solutions to the problems posed by deep space. specially designed habitats and spacesuits may offer a defensive shield to protect astronauts from extended exposure to radiation. nasa is also working on an electric propulsion system that draws energy from the sun. this system would let ships refuel in deep space, without space stations nearby. most ambitious of all, nasa is studying supersonic retropropulsion, a process that fires engines during landing, to help spacecraft land on mars’s surface without crashing.
match the problems with their solutions.
problem
spacecraft expose astronauts to dangerous levels of radiation.
spacecraft cannot refuel in deep space.
large spacecraft are difficult to land safely.
solution
spacecraft may draw energy from the sun.
nasa may equip ships with special habitats.
spacecraft can use supersonic retropropulsion.

Explanation:

To solve the problem - matching, we analyze each problem and solution:

1. Problem: Spacecraft can use supersonic retropropulsion.

Solution match: "Most ambitious of all, NASA is studying supersonic retropropulsion, a process that fires engines during landing, to help spacecraft land on Mars’s surface without crashing." This matches the problem of spacecraft landing safely (Large spacecraft are difficult to land safely) as retropropulsion aids in safe landing.

1. Problem: NASA may equip ships with special habitats.

Solution match: "Specially designed habitats and spacesuits may offer a defensive shield to protect astronauts from extended exposure to radiation." This matches the problem of spacecraft exposing astronauts to dangerous radiation (Spacecraft expose astronauts to dangerous levels of radiation).

1. Problem: Spacecraft may draw energy from the sun.

Solution match: "NASA is also working on an electric propulsion system that draws energy from the sun. This system would let ships refuel in deep space, without space stations nearby." This matches the problem of spacecraft not being able to refuel in deep space (Spacecraft cannot refuel in deep space).

So the correct matches are:

• "Spacecraft can use supersonic retropropulsion." → "Large spacecraft are difficult to land safely."
• "NASA may equip ships with special habitats." → "Spacecraft expose astronauts to dangerous levels of radiation."
• "Spacecraft may draw energy from the sun." → "Spacecraft cannot refuel in deep space."

Answer:

• "Spacecraft can use supersonic retropropulsion." matches "Large spacecraft are difficult to land safely."
• "NASA may equip ships with special habitats." matches "Spacecraft expose astronauts to dangerous levels of radiation."
• "Spacecraft may draw energy from the sun." matches "Spacecraft cannot refuel in deep space."