Tag Archives: JPL

The air is clearing over Perseverance Valley – but what of Opportunity?

MER-B “Opportunity”, the little rover that could, obliterating all expectations for its longevity and roving for nearly 15 years on the surface of Mars….

The rover went silent back in June as one of Mars’ notorious planetwide dust storms kicked up.  Not all of the planet was equally affected, but the spot where Opportunity is trucking around, nicknamed Perseverance Valley for how damn tough this bot has proven to be, was severely affected.  It would be nearly as dark as night even in the middle of the day during the worst of the storm.  Even a nuclear-powered rover like Curiosity would struggle to be useful in those conditions (it was, ironically, much less dusty in Gale Crater), but for a solar-powered rover, such darkness is disastrous.  Opportunity likely completely depleted its batteries.  The good news is that it’s summer in Perseverance Valley, and the dust storm acted like a thermal blanket; the rover should have stayed warm enough that its batteries will not have frozen, as likely killed the Spirit rover when it got stuck in a position where it could not receive adequate sunlight over the long winter.  The bad news is . . . the rover’s been showing serious signs of age already, and it could be partially buried under dust now.  It’s hard to say what condition it’s in.

Still, the storm has been abating.  Soon, the tau (a measure of particulates in the atmosphere) is expected to drop below 1.5, at which point there should be enough light to charge the batteries up.  It is designed to recover from a complete power loss, and once it has sufficient power in its batteries, it should be able to phone home.  And to improve the odds some more, NASA is also sending regular “are you there?” signals to it, while listening for any signals via both the Deep Space Network and the orbiting assets such as Mars Odyssey 2001, Mars Reconnaissance Orbiter, MAVEN, and ESA’s Mars Express, all of which are designed to act as relays for any compatible lander on the surface of Mars.

But NASA cannot afford to listen forever.  Once the tau drops below 1.5, a clock will start to tick.  They will continue actively pinging the rover for 45 days.  After that, a passive listening campaign will continue for another 90 days, in hopes that the upcoming dust devil season may clean off any accumulated dust on the solar panels.  But if Opportunity does not respond by the end of that campaign, they may have to finally close the door on this astonishingly successful mission.

So cross your fingers that Oppy calls home!  😉



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5,000 Martian Sunrises

Mars Exploration Rover B “Opportunity” has blown away all predictions for longevity.  I mean, NASA/JPL/APL always design their spacecraft to last as long as possible within budget constraints, but even by their own high standards, this thing has lasted a long, long time.  And just a few days ago, it saw something nobody thought it ever would — it’s 5,000th Martian sunrise.

And it finally took its first selfie.  😉  Well, not exactly the first, since it has taken pictures from its mast before.  But this was the first selfie taken using Opportunity’s robot art, similarly to how Curiosity regularly takes selfies.  Opportunity’s arm doesn’t have as good of a camera; it’s really meant for up-close microscopic images.  But it was a nice way of commemorating Sol 5,000:

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A lost NASA satellite has been recovered!

This is an amazing story.  An amateur satellite hunter, Scott Tilley, was looking for signs that the Zuma spacecraft might have actually survived the Falcon 9 launch that supposedly dumped it into the ocean.  After all, the only word we have that it failed to separate was an unnamed congressional staffer; in these circles, that amounts to nothing more than rumor.  So Tilley was looking for unaccounted for radio signals that might be consistent with the Falcon 9 launch.  He didn’t find Zuma, but he did find something else: a NASA satellite named IMAGE that had lost contact years ago.

IMAGE was built as a highly capable space weather forecasting and research tool, but in 2005, it suddenly stopped communicating.  NASA had hoped that an upcoming eclipse season (where the spacecraft would spend relatively long periods in the Earth’s shadow) would cause its batteries to drain, forcing it to reboot, but no signal was recovered.  So eventually the project had to disband and move on.

Now, years later, it seems IMAGE has finally managed to reboot itself after all.  NASA is calling on old engineers, pulling up old drawings and specs, and preparing to try and regain routine control of the spacecraft.  If successful, it would be a huge benefit to space weather forecasting.  So cross your fingers!

Long Dead NASA Spacecraft Wakes Up

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Voyager 1’s main thrusters still work!

The Voyager 1 spacecraft has been flying for over 40 years now, an incredible history.  But recently, mission controllers at JPL have found that the attitude control thrusters appear to have degraded performance.  Concerned they might not last out the last few years of expected performance, JPL decided to try something else — to use the trajectory correction maneuver thrusters.  These thrusters were responsible for changes to the spacecraft’s actual trajectory, and are larger than the attitude control thrusters.  More importantly, they have a lot fewer hours of operation.  But there was a catch — the last time these thrusters fired, it was to set up the flyby of Saturn in 1980.  Could they still find the documentation to write a program to fire the thrusters in tiny pulses for attitude control?  And would the thrusters still work after being asleep for so long?

Well, the answer to both was “yes”, and JPL believes they’ve bought at least another 2-3 years for the spacecraft.  With the expected end of mission (or, end of extended-extended-extended-n-times-extended-mission) in 2020 or so, that’s pretty significant; this means they are back to expecting that declining electrical power output will be what kills the spacecraft.

At any rate, these magnificently engineered engines are working like a champ, and they will continue to be used, possibly for the remainder of the mission, with the attitude control thrusters now relegated to a backup role.  Meanwhile, they are exploring the same option for Voyager 2, although its attitude control thrusters still appear healthy.



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Cassini’s last images have been taken

Cassini took its last pictures, including a stirring set of images showing Enceladus off the limb of Saturn, and has been downlinking them to Earth.  JPL is putting them up as quickly as possible.  The main communications currently are still through the big Mars antenna at Goldstone, but the big dish at Canberra has started to pick up the carrier signal and will soon take over the task of talking to Cassini; that dish will be dedicated to Cassini for the remainder of the mission.  Around midnight here in Central Daylight Time, Cassini will pass the orbit of Enceladus and begin moving once more into the domain of the ring system.  Finally, at 5:32 CDT, Cassini is expected to lose its lock on Earth due to excessive aerodynamic forces, and at 6:55 CDT, the signal received on Earth will cut off.  It will be over.

But it will not be soon forgotten.

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Cassini: just a little over a day left

The Cassini spacecraft has just one day and eight hours left to live, and after thirteen years in Saturn orbit, it’s hard not to feel a little choked up thinking about it.  I just rewatched this animation, and I gotta admit . . . it got awfully dusty in here . . . .

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Cassini’s “Goodbye Kiss” of Titan is complete

One step closer to the bittersweet end of a magnificent mission….  Cassini said goodbye to Titan today, where its companion, the Huygens probe, rests permanently.  There was a final sequence of images taken, which have now been downlinked to Earth.  Here’s one of the raw images in the sequence, this one taken through the CL1 and CB3 filters, which allows it to peer a bit through the smog to make out a hazy glimpse of Titan’s surface features:

Goodbye, Titan….I hope we visit again soon.  😉

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