ESA Rosetta mission: Crippled Philae lander endeavours to transmit relevant data

Animator's picture of Philae on the comet 67/P now appears more idealistic and hugely optimistic.

A report on the Philae spacecraft's verified Twitter feed suggests the probe has successfully "hopped" into a new position which may enable its solar panels to work

There was fresh hope for the Rosetta mission after scientists reconnected with the probe which could be holding key information about how life on Earth began.

The 25-year mission was thrown into jeopardy after the Philae craft bounced away from its landing site on the comet 67P/Churyumov-Gerasimenko and became stuck under a cliff.

Scientists had been working on attempts to find and move the probe before it ran out of battery power.

But on Friday those plans were abandoned and instead they began drilling beneath the surface of the comet in an attempt to get some samples on board for analysis.

ESA Philae landers' instruments listed. Consert, Romap, SD2 and Mupus have been initiated but results are unknown.

Contact with the lander was lost before the data could be sent back to Earth, but late last night Philae re-established radio contact with its orbiting Rosetta satellite and is sending data from the surface.

However, less than an hour later scientist confirmed the lander was "getting tired" and the battery voltage was approaching the limit.

Daniel Scuka, Senior Editor for Spacecraft Operations at ESOC, said on the mission blog: "While the search for the final landing site is still on-going, the lander is racing against the clock to meet as many of the core science goals as possible before the primary battery is exhausted.

"Under the low illumination conditions at Philae's location, it is unlikely that the secondary batteries will charge up enough to enable extended surface operations."

They confirmed that they had received data from Philae, and that the drill had moved up and down, but they were unsure what data they had.

A report on the spacecraft's verified Twitter feed, Philae Lander @Philae2014, suggests the craft has successfully "hopped" into a new position, possibly one that will enable more sunlight to shine on its solar panels.

The first of two messages at about 11pm read: "I just started lifting myself up a little and will now rotate and try and optimise the solar power."

This was quickly followed by another which said: "My rotation was successful (35 degrees). Looks like a whole new comet from this angle."

Philae has imaged three different spots on the comet, it was confirmed.

This may be the sum total of knowledge taken out of the Rosetta Philae lander chapter of the mission.

However, in a less optimistic update just before midnight Mr Scuka added: "On board Philae, system voltage has fallen very close to 21.5V; below that, the battery won't last much longer. At this time, there is insufficient sunlight to provide power."

Rosetta The comet is a remnant from the early solar system and may hold clues about how life on Earth began.

Many scientists believe that comets were the driving force, delivering water and amino acids to the planet during the "bombardment phase" about four billion years ago.

If the link with the probe is lost, there is a faint possibility that the solar panels will begin working again when the comet's orbit brings it closer to the Sun.

"We can only hope that as we approach the Sun, maybe in August, if we don't have dust or a huge coma [a dust cloud around the comet] blocking the Sun, then perhaps there would be a chance we could come back and at least see how the lander is doing," said Valentina Lommats, of the German Space Agency.

Crucially, the team had still not located the lander on Friday. On Thursday, team members said they believed Philae had bounced twice before settling in a crater east of the original landing site.

However, scans by the Osiris camera on board the Rosetta mother ship failed to locate the probe.

Rosetta has now started scanning other areas.

An animated gif of the Philae lander departing from Rosetta on its risky but calamitous journey onto the comet 67/P.

However, scientists were confident that they had collected a huge amount of a data, around 90 per cent of what they were hoping for before the solar panels were needed to extend the mission.

Even if Philae's job is finished, the Rosetta mission is to continue.

Rosetta will remain alongside the comet as it moves closer to the Sun.

Instruments on board will analyse the gases of the tail and the comet's interior, measure dust grains and study its atmosphere and gravity.

The comet will reach its closest distance to the Sun on Aug 13 next year, at about 115 million miles, roughly between the orbits of Earth and Mars.

Robot with brush, water, wiper tackles solar panel cleaning

Credit: Sinfonia Technology (previously known as Shinko Electric Company)

At large-scale solar plants, keeping the surfaces of solar panels free from dust, sand and bird droppings is not just a matter of finicky housekeeping.

It can be a matter of plant profitability. Dirty panels lower power generation efficiencies.

Bird droppings on panels, for example, block the sunlight.

A Tokyo-based company has a solution. Sinfonia Technology announced late last month that it has developed a robot with camera and sensors that can move autonomously and clean solar panels at large-scale solar power plants.

Sinfonia's robot has a distinction in being "autonomous" in that, rather than tethered to rails, the robot is able to move from panel to panel, to tackle the panels' dirt and debris.

The robot is equipped with scrub brush, wiper and detergent; and also sprinkles water stored in its tank. The robot can work in the dark; it has LEDs, having wavelengths in the infrared range.

Aside from autonomy, another key distinction is that Sinfonia's robot can handle the fact that not all solar panels are alike; the robot is designed to tackle panels that tilt in different ways.

To clean tilted solar panels on a mounting system, the robot can move on a planes tilted at 5-30°. If there is a gap between panels, the robot can go over a gap of 50cm or less and can deal with a height difference of 30cm or less.

The robot is powered by a battery and is capable of wireless data transmission. A tablet can be used to check the robot's status—to check if, for example, it has enough water or to check the battery charge remaining.

Sinfonia Technology, in promoting the benefits of its panel-cleaning robots, also noted cost advantages over using manpower for cleaning panels.

Generally, experts say that, for large-scale solar panel installations, attention to keeping the panels clean makes sense.

Earlier this year, however, a study out of the Jacobs School of Engineering at University of California San Diego, in quantifying losses of electricity output due to dirty solar panels, found panels that hadn't been cleaned, or rained on, for 145 days during a summer drought in California lost on average a little less than 0.05 percent of their overall efficiency per day.

The overall conclusion was, that cleaning the panels often was not worth the cost, according to the study's engineers.

They cautioned, though, that their study focused on smaller systems and that, for very large installations, economies of scale may mean that washing panels was worth it.

Sharp, meanwhile, is another Japan-based company showing interest in devising automatic ways to clean solar panels.