Time is running out for NASA鈥檚 Opportunity rover. A dust storm that has been raging on Mars since early June is starting to subside, potentially giving the rover enough sunlight to charge its batteries, but NASA has set a before it gives up trying to wake it.
The Opportunity rover is run entirely on solar power, so a dust storm like this one, which has blocked out upwards of 99 per cent of sunlight on the surface, can be catastrophic. The last signal received from Opportunity was on 10 June. Since then, it has been in sleep mode, using any power it had left to keep its batteries warm enough to weather the frigid, sunless surface of Mars.
Now that the planet-encircling storm has begun to clear, rover operators are sending Opportunity wake-up calls three times a week with orders to send back a beep if it鈥檚 alive. The hope is that sleep mode kept the battery safe, and now a Martian dust devil could come along and blow the sand off the rover鈥檚 solar panels, allowing it to charge up again.
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But on 30 August, NASA announced that those wake-up calls will only last for 45 days, a much shorter rescue effort than the one for the Spirit rover in 2010 and 2011.
鈥淲e listened actively for 11 months to try to find Spirit,鈥� says former Opportunity flight director Mike Siebert. 鈥淭he recovery attempt for Spirit was much less likely, but we gave it more time.鈥� Plus, he says, the 45 days will not get us to Martian dust devil season, which starts around December, when the solar panels would most likely get cleared off.
In mid-October, operators will switch to several months of 鈥減assive listening鈥�, in which they continue to monitor Mars for any signals from Opportunity but do not send it any commands. 鈥淚t鈥檚 much less likely for Opportunity to contact us on its own in the passive listening phase,鈥� says Siebert.
The Opportunity and Spirit rovers were designed to last for 90 days on the Martian surface. Spirit lasted over 20 times longer than that, and Opportunity is in its 15th year now. But this dust storm has been one of the most intense we鈥檝e ever observed on Mars, and it may have spelled the end of the rover鈥檚 long mission.
