#### Answer

If the astronaut throws the big wrench away from the ship, the wrench will gain momentum directed away from the ship. By conservation of momentum, the astronaut must gain the same magnitude of momentum toward the ship.

#### Work Step by Step

The astronaut can apply conservation of momentum to return to the ship. If the astronaut throws the big wrench away from the ship, the wrench will gain momentum directed away from the ship. By conservation of momentum, the astronaut must gain the same magnitude of momentum toward the ship.