Oh, I believe you are right. Look over on the upper right, below the boulder. You can see where Bigfoot did a face plant. There are the imprints or two eyes, a nose, and a mouth!
Posted on 11/13/2014 4:56:14 PM PST by NormsRevenge
After a historic but awkward comet landing, the robot probe Philae is now stable and sending pictures - but there are concerns about its battery life.
The lander bounced twice, initially about 1km back out into space, before settling in the shadow of a cliff, 1km from its intended target site.
It may now be problematic to get enough sunlight to charge its battery systems.
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The key issue vexing controllers right now is the lighting conditions.
Philae is receiving about 1.5 hours of illumination during every 12-hour rotation of the comet.
This will be insufficient to top up its battery system once the primary charge it had on leaving Rosetta runs out. That was some 60-plus hours.
It means Philae is unlikely to be operating in its present state beyond Saturday.
(Excerpt) Read more at bbc.com ...
I suppose that my suspicious theory that the harpoons actually did deploy, but into solid rock, probably would have sent Philae all the way back to Rosetta! (Especially in light of the downward thruster not working.)
I think your example confuses weight and mass. The initial speed imparted to a craft by the suggested mousetrap mechanisms depends on the mass of the craft, in this case ~100kg. The height attained due to this speed is then independent of the mass. As Galileo noted, any given mass may be considered as two smaller masses conjoined, and hence the motion of objects in a gravitational field must be independent of mass ( in so many words ! )
If a harpoon is ejected, then the lander reacts with and equal and opposite change in momentum. It shouldn't matter if the harpoon penetrates or not. This is assuming that the harpoon has some phase of free flight, however short.
Even so, I don't think your point can be gainsayed. I think it depends on the details of the event. They should have just landed!
It still would not take much impetus to move it off the surface. Yes, it has mass, but not too much force is needed to move it. Question then is how much force is stored in the mousetrap spring and how fast can it be applied? It may not need to be very much. The acceleration of gravity on that comet is merely 1.5mm/sec^2. They need a small bounce of a few meters to get the lander out into the sunlight for a longer exposure for each "day." How far? I certainly don't know. Maybe they need a "better mouse trap." By-the-way, those were rat traps. . . a bit larger than meese traps. heheheheh
i just looked it up and you can get a little over 3 Joules of energy out of a Rat Trap Spring at the lever end. . . hmmmm that's almost 10 Joules from three of them. Although I was posting facetiously there just might be enough there to get something accomplished. . . Perhaps bigger rat traps would have been enough. LOL!
I found a report that stated the gravity acceleration of 67P is only 1.5mm/sec^2. ESA publicly stated it "bounced 1km out into space and then 1km over," but that may be a wild, gassed guesstimate. . . or it was calculated from their knowing the approach velocity, the elasticity of the landing legs, mass of the lander and exactly what happened. I want to know why it bounced only once, since, according to reports the landing system—harpoon, thruster, ice screws, etc,—did not work at all.
I am pretty sure that it was in today’s press briefing that they spoke about the second bounce. I think they said the first bounced lasted 3hrs and the second bounce lasted 7mins. Just from memory, without double-checking.
It is a very low-g environment, and your rat traps are definitely not out of consideration.
If we take 10 joules at face value, this translates to v = sqrt( 2E/m ) = sqrt( 20/100 ) m/sec = .44 m/sec, and the height attained would be 1/2 X .442/10-3 m = 96.8 m
Correct me if I'm wrong! I mean that seriously.
Ah, thanks, I had not heard that. If there was a second bounce, then there was a third, fourth, perhaps a fifth, each with shorter, diminishing times and returns until abated and resting.
Thanks, Doc. . . looks good to me. I like it.
I think they should have included some spring devices, not necessarily rat traps, in the legs for just such an eventuality to allow moving the lander. But then I am a belt AND suspenders type of guy. With an achieved altitude (distance?) of ~100 meters or so, they should have been able to move the lander away from the shadowed cliffs some fraction of that distance. With some judicious timing of when the springs were triggered (moused?) they could grossly direct on which vector the lander heads.
Yeah, the landing was a complete fiasco, in terms of the objectives. They are playing rhetorical games saying that it "landed twice' etc. all this is due to the forgiveness of the low-g environment. It seems to me that they did not gain any of the scientific objectives of the lander, which on that account would have to be judged a complete failure. Well, it was fun.
The lander touched down right where they wanted it to. All it had to do was stay there, which in this case was a nontrivial objective. They were banking on the harpoons, and that didn't work out. There's gotta be an "I told you so" faction on the team! ... unless they got rid of them already ... it's been ten years, after all.
Oh lookie, it’s a conspiracy nutter. It was Bigfoot!
Dingus.
LOL! I am wondering how much of the lander's control electronics—such as the harpoon triggers and the nitrogen thruster controls—were fried in the electrical discharges between the comet and the lander as the potentials were attempting to be balanced as the lander approached. There were comments about contact and electrical issues as Philae approached 67P.
In the split second just before the Deep Impact mission 880 Lb. copper projectile impacted Comet Tempel 1 at 22,000 MPH, there was an intense double flash of lightning as huge electrical potentials exchanged between the comet and the impactor and blew out all the sensors on that probe.
Oh, I believe you are right. Look over on the upper right, below the boulder. You can see where Bigfoot did a face plant. There are the imprints or two eyes, a nose, and a mouth!
Ah yes. My difficulty is in understanding how such large potential differences could be maintained in the environment of the solar wind. I would be interested in your explanation.
In a way, they don't. It is what causes comets to be comets as they move through the electrical atmosphere of the sun. Think about it. As a comet moves closer to the sun, the temperature does not rise as much as does the electrical potential. Infact, the coma and tail of a comet form far before the temperature could possibly rise to even the melting point of H2O much less its boiling point, even in a vacuum, if there were water on a comet. Comets start forming these out beyond the orbit of Jupiter and beyond. Temperatures in space out there from the sun range from -128 to -190 C on objects in a vacuum. That is, shall we say, REALLY cold. As Hale-Bopp approached the orbit of Mars, its Coma was larger than the sun, and it grew even larger! How can this be, if it is merely out-gassing steam? It really cannot. It can only be if it is a huge plasma cloud of charge particles, each of which is attempting to get as far from other similarly charged particles as possible as fast as possible. . . and others are being pushed away from the sun by other similarly charged particles: the solar wind! This is the comet trying desperately to equalize its charge with the space around it!
What is another characteristic of any charged plasmas? Look at any neon light. Look at the aurorae borealis and australis. They glow. What do comets and their comas and tails do? They glow with the electrical discharge.
Every comet we have ever visited has been indistinguishable from an Asteroid. They are lumps of rock. The only difference is the electrical charge they carry. For example Halley, Tempel 1, and 67P/Churyumov-Gerasimenko have all shown no signs of H2O at all. These comets have had the appearance of a lump of coal or fresh Macadam. . . reflecting approximately 4% of the light that falls on them, not dirty ice. When the Deep Impact collision occurred, they did find OH radicals and H2O in the ejecta but those were found only in a spew almost 180º back from the point of impact and no where else. The Deep Impact lead scientist Dr. Sunshine was quoted as saying that the water found was "chemically pure, almost as if it had just been created!" The Solar Wind is essentially stripped Hydrogen atoms (Protons and electrons . . . plasmas) which when they encounter Oxygen electron machined from from the comet combine to for OH and H2O, just as the lead Deep Impact scientist said:
"In the Deep Impact data we're essentially watching water molecules form and then dissipate right in front of our eyes," said (Dr. Jessica M.) Sunshine, who said her first reaction to the M3 data was skepticism.
Note that free Hydrogen exists in space and ionized in the Solar wind as both Hydrogen and Deuterium and each can form water with equal alacrity. Add a very, very highly charged plasma field and you will get water signatures from a dry as the Sahara desert asteroid with a highly elliptic orbit which has picked up a HUGE charge that it discharges as it gets closer to the oppositely charged sun. No heat creating steam, but rather electric forces creating very highly charged plasma, the most common form of matter which we see everywhere we look in space.
Note also that some ordinary asteroids have suddenly spouted comas and tails in the solar wind when the sun is very active. Planets like mercury have tails and even some stars have tails as well.
Are the people working in this mission called Philae Landerers?
*facepalm*
I don't pick through vomit. Form some coherent thoughts and try again. Or better yet, go play with some shiny things in your happy place.
The comet has no ice and a pretty powerful argument for an orbitally induced charge accumulation, yet electrical potential differentials are not even addressed by the space scientists. Nevertheless, a big charge differential could easily have smacked the lander a mile away. And notice those lander feet, while having acknowledged purposes, also look like pretty good insulator technologies.
Is such a simple, obvious concept. For these scientists to refuse to acknowledge it while publicly drawing attention to it is really irritating.
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