Late last night the Mars Phoenix Lander put itself to sleep after experiencing a malfunction brought on by its deteriorating power supply.
The craft also unexpectedly switched over to its backup electronics and shut off one of its batteries.
The news was surely a disappointment, but not entirely a surprise, for NASA engineers, who had been expecting problems with the rugged lander right about now.
That’s because the Martian arctic is moving into fall, and as the days get shorter, poor Phoenix has been losing its fire [in the form of sunlight to power its instruments].
An image from the Mars Reconnaissance Orbiter shows the Martian north pole, with the Phoenix lander at about the 10 o’clock position
—Image courtesy NASA/JPL-Caltech/Malin Space Science Systems
It’s not just the scientific equipment that needs power.
Mars is pretty frigid even in summer, and right now it doesn’t get much warmer than -50 degrees Fahrenheit (-45 degrees Celsius) during the day, with overnight temperatures plummeting to -141 degrees Fahrenheit (-96 degrees Celsius).
Phoenix needs a system of “survival” heaters to keep the whole craft from freezing to death, and those heaters need electricity.
Shortly after touchdown in May, the craft was generating 3,500 watt-hours worth of electricity a day from its solar panel “wings.”
That number has been dropping since August, and in the coming months the lack of sunlight will likely spell doom for the lander.
It’s been a good run for Phoenix, which was originally slated to work for 90 days but recently completed its fifth month of scientific study in the Martian arctic, proving it’s made of the same mettle as its older cousins, the long-lived rovers Spirit and Opportunity.
But unlike the hardy rovers roaming Mars’s equatorial region, the stationary lander was set down in a spot in the north that will soon experience numbing temperatures and almost a hundred consecutive days with no sunlight.
(Watch video of Phoenix seeing snow on Mars!)
Yesterday NASA engineers had announced plans to make an attempt to prolong Phoenix’s life a tad by cutting off its arm and nose.
More precisely, the team was slated to turn off heaters one by one, starting with the heater that warms the robotic arm and the lander’s “bake and sniff” oven, the thermal and evolved-gas analyzer.
The robotic arm camera seen with all its LED lights on
—Image courtesy NASA/JPL-Caltech/University of Arizona/Texas A&M University
Shutting off that one heater would save 250 watt-hours of power a Martian day, NASA says.
Following the malfunction, the team decided to turn off two heaters, the one warming the arm and oven and another warming the craft’s pyrotechnic initiation unit (the bit that turns on its landing thrusters).
With just two heaters left, Phoenix will mostly be a weather monitor, and its meteorological instruments should keep collecting data into December.
When NASA shuts off the weather station’s heater, the lander will have just one left to keep itself running.
“At that point, Phoenix will be at the mercy of Mars,” Chris Lewicki, NASA’s lead mission manger at the Jet Propulsion Laboratory, said in a press release.
“It could be a matter of days, or weeks, before the daily power generated by Phoenix is less than needed to operate the spacecraft,” he added.
In keeping with its namesake, the regenerating phoenix bird of myth and legend, the Mars lander is programed with a “Lazarus mode”—if by some miracle the craft’s solar cells are still working in the spring, it could wake up again and “phone home” to let NASA know it’s ready for more.
Sadly, Phoenix scientist Michael Hecht told Wired Science in September, “while that’s theoretically possible, I don’t think that there is anyone on the engineering team who thinks that is going to happen.”