Historic pictures sent from mars

A Nasa spacecraft has sent back historic first pictures of an unexplored region of Mars.

The Mars Phoenix lander touched down in the far north of the Red Planet, after a 680 million-km (423 million-mile) journey from Earth.

The probe is equipped with a robotic arm to dig for water-ice thought to be buried beneath the surface.

It will begin examining the site for evidence of the building blocks of life in the next few days.
A signal confirming the lander had reached the surface was received at 2353 GMT on 25 May (1953 EDT; 0053 BST on 26 May). The message took 15 minutes to travel to Earth from Mars at the speed of light.

Wait just a minute! What? "A signal confirming the lander had reached the surface was received??? At the speed of light???" How in the world can a signal be sent 423 million miles without some kind of signal booster? I mean, even the phone company has to have signal boosters. On top of a "signal" confirmation, there were phenomenal pictures, with high quality even! How can this be? Can someone explain this to me???