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Crédit image: Steve Squyres [credit: NASA]

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Signalé
BooksInMirror | 10 autres critiques | Feb 19, 2024 |
Steve Squyers, the Principle Investigator on the Spirit and Opportunity Mars rover missions, takes readers through the development of those missions, from early discussions about what to do next on Mars, through the planning, design and building of the rovers, to their scientific adventures on Mars up through their first shutdown for the Martian winter.

He goes into a lot of detail about all the various trials and tribulations involved: convincing people at NASA to do the two-rover mission, funding and scheduling problems (so many scheduling problems!), technical problems that cropped up both before and after launch... And, to be honest, many of those details are not quite as interesting as you might want them to be. But Squyres' account does give a good general sense of what it's like to scramble desperately to get a something like this off the ground and onto Mars, and it does leave me impressed that they got it to work at all, never mind as incredibly well as they did.

And there's no denying that both Spirit and Opportunity were immense successes. It's rather amusing to read Squyres words here, writing in 2004 or 2005 and anticipating the rovers' future: "Surely they'll die before long... within months, perhaps, or in a year or two at the outside. Even in the most optimistic scenario, it's hard to believe that Spirit can survive a second winter on Mars. And Opportunity, the good-luck rover in the warm and sunny climate of Meridiani Planum, will succumb, too, one way or another." Spirit, of course, ended up functioning for over six years on Mars, and good-luck rover Opportunity made it nearly fifteen. Fifteen! Not bad for machines whose nominal operational lifetime was supposed to be 90 days!

So, even though this book held my attention much, much better at some points than at others, the rovers themselves, and the folks behind them, have my complete and unflagging respect.
… (plus d'informations)
½
 
Signalé
bragan | 10 autres critiques | Aug 31, 2022 |
This is like Andy Weir's "The Martian," but it's all true! A whole series of problems arise, and Squyres and the JPL team have to engineer their way through them. I loved it.

> But back during the earliest days of the project Glenn realized that someday we might need the flexibility to deal with a broken flash file system, and he put INIT_CRIPPLED in the system and left it there. And when the anomaly hit, it saved the mission.

> it’s the Spirit guys who’ve consistently felt shortchanged by events ever since we landed. We rejoice when Spirit touches down safely, and then Opportunity rolls to a stop right in front of a stack of sedimentary rocks. We rejoice when Spirit drives 50 meters in a sol, and then Opportunity reels off 140. We rejoice when Spirit gets to Bonneville and finds a pretty view, and then Opportunity gets to Endurance and finds layered cliffs of sediments

> The Pathfinder system was a wonderful way to land on Mars, but it was definitely not rover-shaped on the inside. Using the Pathfinder lander would mean that we’d have to find a way to fold our rover up into a tetrahedron, and then do the same trick again in reverse once we landed.

> The original plan for the parachutes had been the same as for the airbags: use the Pathfinder chute. But by the time Adam showed up on the project, that idea was already dead. The lander had grown so much that there was no point in even testing the Pathfinder design to see if it might work. Simple calculations were enough to prove that the Pathfinder chute was too small to keep us from crashing

> Something wasn’t right. They flew an identical chute the next day, under perfect conditions again. Again the chute exploded. They had a problem. … when the forces that want to pop the chute open are repeatedly overcome by other forces that flap it closed again. Squidding had never been seen in a parachute like ours before, not in thirty years of testing. But now this chute, the one that Adam was betting would take us to Mars, was squidding … Adam found a tape measure, and sure enough, the vent hole in the middle of the parachute was too big. Something hadn’t been communicated quite right between JPL and the parachute vendor. … The chute still opened too slowly. Even more frustrating, measurements afterward showed that the vent hole was still bigger than he’d wanted it to be. Miscommunication and aerodynamics were conspiring against him

> But in 2005, the next chance to go to Mars, the geometry was terrible. If we launched in 2005, we’d arrive at Mars when the planet was far from the Sun, and when it was almost as far away from Earth as it ever gets. Solar power would be bad, and communication to Earth would be awful. The mission was so bad in 2005 that it wasn’t clear that it made sense to fly it at all.

> But that doesn’t mean that the rocks of the Columbia Hills aren’t older still. In fact, the water that once soaked the hills may date from some truly ancient epoch that has nothing whatsoever to do with the lake that brought us to Gusev Crater.

> At Meridiani, there’s no question that we found what we came looking for, and more. The rocks there were laid down in liquid water, in an environment that surely must have been suitable for some primitive forms of life.
… (plus d'informations)
 
Signalé
breic | 10 autres critiques | Apr 7, 2022 |
The Lead PI of the Mars Rovers Spirit and Opportunity tells his story.
Excellent book on the woolly world of government funded big science.
 
Signalé
Steve_Walker | 10 autres critiques | Sep 13, 2020 |

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