Though NASA's Opportunity Mars rover remains silent after a massive global dust storm, the space agency has managed to locate the robotic explorer. Images returned by the NASA Mars Reconnaissance Orbiter (MRO) show Opportunity as a tiny object on the slopes of Perseverance Valley, where it has sat since radio contact was lost over 100 days ago.
NASA says the new image was taken by the MRO HiRISE camera from an altitude of 166 mi (267 km). It's very hard for the unaided eye to see Opportunity in the released image, but NASA has also released an animated GIF image that compares Perseverance Valley as it is today with another image taken a year ago. The result is a dramatic "now you see it, now you don't" effect.
Though reassuring, the image is of little direct help in NASA's efforts to rescue Opportunity after the rover's solar-powered batteries were exhausted when the giant dust storm blotted out the sun for weeks. Data sent back by MRO shows that the tau or opacity of the air over the rover is now 1.3 – low enough to allow the sunlight through to the solar panels. Whether the solar panels are free of dust and the robot's systems have escaped severe damage is another matter.
NASA is presently carrying out rescue operations with the Opportunity team at the Jet Propulsion Laboratory (JPL) in California, sending radio signals to the rover several times per day using the Deep Space Network. Meanwhile, the Radio Science Group at JPL is listening for any return transmissions.
Having started over ten days ago, the signals will continue for at total of 45 days. If no reply is heard by then, this could indicate that the electronics aboard Opportunity have frozen during the Martian night, killing the spacecraft, though it's more likely that the panels are simply not getting enough light due to dust settling on them. Even so, JPL will continue to listen for any transmissions in the event that Opportunity manages to reawaken on its own.
Source: NASA
Yeah, a literal whistle to blow Martian atmosphere through at varying velocities. Include a microphone and a speaker in the package. The purpose of the experiment would be to directly measure things like gas viscosity and how it affects sound propagation. Running the tests at different temperatures would also produce interesting data.