A spacecraft glitch delayed the first scientific dig
The Phoenix lander's first dig into the Martian soil for scientific study has been delayed by a glitch on a communications satellite.
Nasa's new robotic craft on the Red Planet had been due to start its real work, after carrying out two practice scoops earlier this week.
But the Odyssey satellite orbiting Mars unexpectedly went into "safe mode" and failed to send the instructions.
Phoenix touched down successfully on Mars' northern plains on 25 May (GMT).
Phoenix landed near the Martian north pole, which is thought to hold large stores of water-ice just below the surface.
It will carry out a three-month mission to study Mars' geological history and determine whether the Martian environment could once have supported life.
Second time unlucky
This is the second time a communications problem has delayed the lander's schedule. The first glitch occurred two days after it touched down, when another satellite, the Mars Reconnaissance Orbiter, turned off its radio.
Phoenix has already taken some practice scoops
Engineers are working to fix the problem with Odyssey, which will remain offline until Saturday, said Chad Edwards, chief telecommunications engineer at Nasa's Jet Propulsion Laboratory in Pasadena.
A preliminary investigation revealed the safe mode was probably triggered by high-energy particles from space interrupting the satellite's computer memory.
With Odyssey temporarily out of service, engineers told the Mars Reconnaissance Orbiter to mediate between the lander and Earth.
Phoenix had planned to dig the first of three shallow pits north of where it landed this week. It would then shovel the soil into a tiny oven to be baked. The resulting gases would be analysed by a variety of scientific instruments.
The mission team has also had to work around a sticky oven door
The Phoenix mission team hope the science excavation work can start very soon.
The lander got its first touch of Martian soil on Sunday when it scooped up and then dumped a handful of soil in a region dubbed the "Knave of Hearts".
The scoop contained intriguing white specks that could be surface ice or salt.
For the second practice "dig and dump", engineers told the robot to go slightly deeper in the same region and use the camera on its arm to take photos in order to perfect its technique.