American space scientists are confident Mars Polar Lander touched down safely tonight. But they are still waiting to hear from the probe. It was due to send its first signal at about 8.40pm tonight, but nothing was received. Scientists speculated that the spacecraft may have gone into a "safe" mode and had not deployed its main antenna properly after landing. They said that another possibility was that it was transmitting, but on an unknown frequency that would take NASA's Deep Space Network of worldwide listening posts some time to locate.
