(CNN) -- Argentina's star-studded line-up began their World Cup campaign with a 1-0 victory over Nigeria in their Group B opener in Johannesburg on Saturday. A goal from defender Gabriel Heinze after six minutes was all that separated the two teams after an inspired display from Nigeria goalkeeper Vincent Enyeama. But South Korea ended the day on top of the group following a 2-0 victory over Greece in Port Elizabeth earlier on Saturday. Goals from Lee Jung-Soo and Park Ji-Sung gave the 2002 semifinalists a comfortable win over the 2008 European cvhampions. Argentina 1-0 Nigeria Enyeama could do little to stop Heinze's powerful early header from a Juan Sebastian Veron corner, but he kept his team alive with a string of acrobatic saves to deny World Player of the Year Lionel Messi. Diego Maradona was delighted to secure his first victory as a World Cup coach, but critical of his strikers for failing to make the game safe. "When you don't kill things off in front of goal you can pay a heavy price. They almost got a draw -- we missed loads of chances," Maradona told AFP. "Players such as Leo Messi and Higuain knocked in around 60 goals last season between them, yet today it was almost as if they couldn't set their sights on goal. "But the win means we can be calm -- we are in the right track."

Who are Argentina's strikers?

(CNN) -- The U.S. space shuttle program retired in 2011, leaving American astronauts to hitchhike into orbit. But after three long years, NASA's successor is almost ready to make an entrance. Orion, the agency's newest manned spaceship, is being prepared for its first mission in December. In future missions, it will journey into deep space -- to Mars and beyond -- farther than humans have ever gone before. Orion comes loaded with superlatives. It boasts the largest heat shield ever built and a computer 400 times faster than the ones on the space shuttles. It will be launched into space on the most powerful rocket NASA has ever made. No astronauts will be aboard the December flight, which will test the spacecraft's systems for future manned missions. Final work on the spacecraft is under way at the Kennedy Space Center in Florida. Orion came one step closer to completion this month with the stacking of the crew module atop the service module. "Now that we're getting so close to launch, the spacecraft completion work is visible every day," Orion Program Manager Mark Geyer said in a statement. A 3,600-mile journey When complete, the Orion capsule will resemble a fencing foil, with a tall spire shooting up from a rounded base. At the top will sit a launch abort system, with downward-facing thrusters that would save the crew from a jarring crash in the event of a rocket malfunction. The bottom portion, the service module, will perform various functions such as in-space propulsion and cargo storage. Nestled between the two will be the crew module, capable of supporting human life from launch until recovery. Attached to the service module will be a United Launch Alliance Delta IV Heavy rocket. For the first time since the space shuttle's debut launch in 1981, the crew compartment will ride on the tip of the rocket rather than hanging onto its side, evoking the configuration of the famous Apollo or Gemini missions.

Where will Orion journey?

Mechanical energy is a combination of the energy of motion or position. This type of energy describes objects that are moving or could move. A moving ball can have energy from motion. An arrow can also have the energy of motion. Both are types of mechanical energy. Can you think of some other examples? Where does the energy of motion come from? It comes from the energy created by position. This energy is stored energy. This means it is not moving yet, but it has the potential to move. How can you store energy? The arrow gains energy from the drawn bow. As the arrow is released, the bow releases its stored energy and puts the arrow into motion. Can you think of some other ways to store energy using position?
Is an object with mechanical energy always moving?