"At the moment it has gone to more than a few people, which amazes me that there is no official statement in the team about what is going on," she said when we spoke early on Thursday. "The people who have heard it in the Opportunity team are like: what's going on and not getting a reply from anyone, it makes everyone a little worried."
This Opportunity executive said the rumors prompted several of her colleagues to start tweeting in support of Opportunity earlier this week, in an attempt to show JPL leadership that the rover is popular and loved by the public. From Tuesday night tweets started popping up with #WakeUpOppy and #SaveOppy. A JPL spokesman told me that they did not know what prompted the sudden grassroots campaign.
"The campaign received a lot of attention from the higher groups," said this staff member of the occasion, "what is good, that was the intention."
When the new recovery plan was made public, there was "a lot of anger, some sadness, a shock" among the members of the team, she said.
NASA officials arrived at this conclusion based on their understanding of how opaque the Martian atmosphere is, a measure known as tau. The greater that value, the less sunlight penetrates the atmosphere to reach the surface. Before it became silent, the instruments of Opportunity recorded a tau of 10.8-greater than the usual tau in the southern hemisphere, which fluctuates between 1 and 2. (During the last major dust storm on Mars, in 2007, surpassed the tau barely 6.)
Without opportunities, NASA has relied on an instrument on the Mars Reconnaissance Orbiter to deliver measurements of the tau. They are less accurate, but they offer good estimates. According to the latest measurements by the orbiter tau is now 1.7. JPL officials believe that when that level drops to 1.5, enough sunlight must peep through the atmosphere to attack Opportunity. That's when they start the clock.
Former and current Opportunity team members and others say that the 45-day period is not long enough to take into account the potential of atmospheric phenomena known as dust-cleaning events. In the past dust dust grains have wiped away on the Opportunity solar panels. Sometimes the wind was so effective that the panels were restored to their original luster.
"I think our best hope has nothing to do with how much dust you have in the air, I think our best hope for the rover is when it gets windy, the dust blows off," says Mark Lemmon, an associate professor at the Texas A & M University, working on the daily operations of the Opportunity rover. "That happened with Opportunity in a reliable and repeated manner, and the season before that is approaching." Such dust-cleaning events are common between November and the end of January.
Engineers have performed simulations that predict the current conditions of Opportunity. But they can not explain how much dust remains – if any – on the Opportunity solar panels. "The first results [of the simulations] suggest that if tau was lower than about 1.5, there is a chance, depending on the dust load on the panels, that we might hear from Opportunity, "says Matt Golombek, the project scientist for the Mars Exploration Rover mission, which relates on Occasion and the now defunct Spirit. "Although we have an estimate of the dust in the atmosphere, we have no idea how much dust there is on the panels."
Source link