Starship Asterisk*

http://apod.nasa.gov/apod/ap090601.html wrote:
Explanation: Will Spirit be able to free itself from soft ground on Mars? The robotic Spirit rover currently rolling across Mars ran into unexpectedly soft ground last month while exploring the red planet. A worry is that the ground is so soft that Spirit won't be able to free itself, will have to stay put and thereafter study what it can from its current position near an unusual martian land feature named Home Plate. Pictured above, the front left wheel appears to be primarily digging itself in when spun, while on the other side, the front right wheel no longer spins and is dragged by the five year old mechanical explorer. NASA continues to study the situation, and engineers and scientists have not yet run out of ideas of how to use Spirit's six wheels. Far across Mars, Spirit's twin Opportunity continues on its two year trek toward Endeavour crater.

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My Cousin Vinny (1992)

Vinny Gambini: Ms. Vito, it has been argued by me, the defense, that two sets of guys met up at the Sac-O-Suds, at the same time, driving identical metallic mint green 1964 Buick Skylark convertibles. Now, can you tell us by what you see in this picture, if the defense's case holds water?

[Lisa examines the picture]

Vinny Gambini: Ms. Vito, please answer the question: does the defense's case hold water?

Mona Lisa Vito: No! The defense is wrong!

Vinny Gambini: Are you sure?

Mona Lisa Vito: I'm positive.

Vinny Gambini: How could you be so sure?

Mona Lisa Vito: Because there is no way that these tire marks were made by a '64 Buick Skylark convertible. These marks were made by a 1963 Pontiac Tempest.

D.A. Jim Trotter: Objection, Your Honor! Can we clarify to the court whether the witness is stating opinion or fact?

Judge Chamberlain Haller: This is your opinion?

Mona Lisa Vito: It's a fact!

Vinny Gambini: I find it hard to believe that this kind of information could be ascertained simply by looking at a picture!

Mona Lisa Vito: Would you like me to explain?

Vinny Gambini: I would love to hear this!

Judge Chamberlain Haller: So would I.

Mona Lisa Vito: The car that made these two, equal-length tire marks had positraction. You can't make those marks without positraction, which was not available on the '64 Buick Skylark!

Vinny Gambini: And why not? What is positraction?

Mona Lisa Vito: It's a limited slip differential which distributes power equally to both the right and left tires. The '64 Skylark had a regular differential, which, anyone who's been stuck in the mud in Alabama knows, you step on the gas, one tire spins, the other tire does nothing.

[the jury members nod, with murmurs of "yes," "that's right," etc]

Vinny Gambini: Is that it?

Mona Lisa Vito: No, there's more! You see? When the left tire mark goes up on the curb and the right tire mark stays flat and even? Well, the '64 Skylark had a solid rear axle, so when the left tire would go up on the curb, the right tire would tilt out and ride along its edge. But that didn't happen here. The tire mark stayed flat and even. This car had an independent rear suspension. Now, in the '60's, there were only two other cars made in America that had positraction, and independent rear suspension, and enough power to make these marks. One was the Corvette, which could never be confused with the Buick Skylark. The other had the same body length, height, width, weight, wheel base, and wheel track as the '64 Skylark, and that was the 1963 Pontiac Tempest.

Vinny Gambini: And because both cars were made by GM, were both cars available in metallic mint green paint?

Mona Lisa Vito: They were!

Vinny Gambini: Thank you, Ms. Vito. No more questions. Thank you very, very much.

[kissing her hands]

Vinny Gambini: You've been a lovely, lovely witness.
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Spirit doesn't have the equivalent of 4WD???? One tire is spinning while the other is not??
Don't tell me that the engineers for the motor control system were incapable of designing a simple synchrounous drive. Why didn't they? I bet the managers didn't let them or they had to perform 1,000's of hours of reliability calculations so that they had no time to design it correctly. That's just pathetic. No, that needs shouting. That's just PATHETIC.

Sorry, i cant agree. 55,785,006 kilometers. Is pretty much un-PATHETIC in my book. Go for a walk in Morcombe bay England when the tide is out.. Well see how long before you get stuck....

Mark

mark swain wrote:Sorry, i cant agree. 55,785,006 kilometers. Is pretty much un-PATHETIC in my book. Go for a walk in Morcombe bay England when the tide is out.. Well see how long before you get stuck....

• Unwholesome sandflats waited to suck his treading soles, breathing upward sewage breath. He coasted them, walking warily. A porter-bottle stood up, stogged to its waist, in the cakey sand dough. A sentinel: isle of dreadful thirst. - James Joyce » Ulysses » Episode 3 - Proteus

hgldr wrote:Spirit doesn't have the equivalent of 4WD???? One tire is spinning while the other is not??
Don't tell me that the engineers for the motor control system were incapable of designing a simple synchrounous drive. Why didn't they? I bet the managers didn't let them or they had to perform 1,000's of hours of reliability calculations so that they had no time to design it correctly. That's just pathetic. No, that needs shouting. That's just PATHETIC.

Sorry you have it all wrong. It is six wheel drive, after five years one of the wheel drive motors froze up and now it is thought that a small rock is wedged between two of the remaining five driving wheels. In the "baby powder" like soft soil the three working wheels don't have the traction to drag the other three wheels stuck in a locked position.

http://en.wikipedia.org/wiki/MER-A

Being that the rovers lasted 20X longer than expected; I'd say mission accomplished. 8) Still; where's that tow truck when you need it?
In other words I'd like to see them get out of the soft soil.

Orin

http://en.wikipedia.org/wiki/Iron(III)_sulfate wrote:
<<Ferric sulfate & jarosite have been detected by the two martian rovers Spirit and Opportunity. These substances are indicative of strongly oxidizing conditions prevailing at the surface of Mars. On May 1, 2009, the Spirit rover became stuck when it drove on a soft spot of ferric sulfate hidden under a veneer of normal-looking soil. For the rover mobility, iron sulfate is an harmful stuff with very little cohesion, so that it is very tough for the rover wheels to get a grip on it. The rover had sunk so deep that part of its belly could be resting on top of the dust, which makes it very hard for its wheels to gain traction. If JPL team fails to recover the mobility of Spirit, it could signify the end of the journey for the rover.>>

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http://www.mclendons.com/item.asp?sku=10375030&from=search wrote:
<<It has now been found that ferric ammonium sulfate-ammonium sulfate double salts are effective for the control of lawn moss in turf.>>

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http://antwrp.gsfc.nasa.gov/apod/ap991227.html wrote:
Explanation: This spongy-looking stuff has a temperature of 2 million degrees Fahrenheit ... and has been dubbed "Solar Moss". The false-color TRACE image above was recorded in extreme ultraviolet light on October 18. It shows the solar moss associated with hot magnetic plasma loops arching above one of the Sun's active regions. The moss is the dark blue and white fluff that seems to cover areas between the bright white bases of the loops. Solar moss has been seen to spread, typically persisting for tens of hours, and may form rapidly following a solar flare. Solar moss isn't found growing only on the Sun's north side, but as a rule seems to lie above the photosphere or visible surface, in the transition region of the solar atmosphere. Complex and previously unknown, this feature may provide a clue to the long sought mystery mechanism responsible for heating the Sun's outer atmosphere.

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They should have aired down the tires before hitting the sand. Everyone who drives a 6WD should know that.

Give me the mean to go there and back safely and i will go push it out and i will include all 6 tires change with it.

Spirit's wheels operate similar to those of the Lightning electric Car's where there is an independant motor for each wheel. The wheels are hard though and require no inflation/deflation. The trick might be to raise the two (front/rear) wheels on the stuck side and try to roll slowly backwards on 4. It is tough having your spirit mired though

BMAONE23 wrote:It is tough having your spirit mired though

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. A Midsummer Night's Dream > Act III, scene I

TITANIA: And I will purge thy mortal grossness so
. That thou shalt like an airy Spirit go.
...................................................
. A Midsummer Night's Dream > Act II, scene I

PUCK: How now, Spirit! whither wander you?

Fairy: Over hill, over dale,
. Thorough bush, thorough brier,
. Over park, over pale,
. Thorough flood, thorough fire,
. I do wander everywhere,
. Swifter than the moon's sphere;
. And I serve the fairy queen,
. To dew her orbs upon the green.
-----------------------------------------------
. Hamlet > Act I, scene I
.
MARCELLUS: And then, they say, no Spirit dares stir abroad;
. The nights are wholesome; then no planets strike,
............................................
. Hamlet > Act I, scene IV
.
HORATIO: then it draws near the season
. Wherein the Spirit held his wont to walk.
.
HAMLET: Angels and ministers of grace defend us!
. Be thou a Spirit of health or goblin damn'd,
............................................
. Hamlet > Act I, scene V
.
HAMLET: Rest, rest, perturbed Spirit!
-----------------------------------------------
. The Taming of the Shrew > Act II, scene I
.
BAPTISTA: For shame, thou helding of a devilish Spirit,
-------------------------------------------
. The Tempest > Act I, scene II
.
PROSPERO: This blue-eyed hag was hither brought with child
. And here was left by the sailors. Thou, my slave,
. As thou report'st thyself, wast then her servant;
. And, for thou wast a Spirit too delicate
. To act her earthy and abhorr'd commands,
. Refusing her grand hests, she did confine thee,
. By help of her more potent ministers
. And in her most unmitigable rage,
. Into a cloven pine; within which rift
. Imprison'd thou didst painfully remain
. A dozen years; within which space she died
. And left thee there; where thou didst vent thy groans
. As fast as mill-wheels strike. Then was this island--
. Save for the son that she did litter here,
. A freckled whelp hag-born--not honour'd with
. A human shape.
.
ARIEL: I will be correspondent to command
. And do my Spiriting gently.

MIRANDA: What is't? a Spirit?
. Lord, how it looks about! Believe me, sir,
. It carries a brave form. But 'tis a Spirit.
.
PROSPERO: Spirit, fine Spirit! I'll free thee
. Within two days for this.
-----------------------------------------------
. Love's Labour's Lost > Act V, scene II
.
KATHARINE: He made her melancholy, sad, and heavy;
. And so she died: had she been light, like you,
. Of such a merry, nimble, stirring Spirit,
.
ROSALINE: Why, that's the way to choke a gibing Spirit,
... But if they will not, throw away that Spirit,
-----------------------------------------------
. King Lear > Act III, scene IV
.
Fool: A Spirit, a Spirit: he says his name's poor Tom.
.
KENT: What art thou that dost grumble there i' the straw?
. Come forth.
...................................................
. King Lear > Act IV, scene VII

KING LEAR: You are a Spirit, I know: when did you die?
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. Antony and Cleopatra > Act IV, scene XV
.
MARK ANTONY: Now my Spirit is going; I can no more.
.
CLEOPATRA: Let's do it after the high Roman fashion,
. And make death proud to take us. Come, away:
. This case of that huge Spirit now is cold:
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The Merchant of Venice > Act V, scene I

LORENZO: The motions of his Spirit are dull as night
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. Romeo and Juliet > Act III, scene I
.
BENVOLIO: That gallant Spirit hath aspired the clouds,
. Which too untimely here did scorn the earth.
-----------------------------------------------
. Measure Fore Measure > Act III, scene I
.
CLAUDIO: Ay, but to die, and go we know not where;
. To lie in cold obstruction and to rot;
. This sensible warm motion to become
. A kneaded clod; and the delighted Spirit
-----------------------------------------------
. King Henry IV, part II > Act IV, scene V
.
KING HENRY IV: Let there be no noise made, my gentle friends;
. Unless some dull and favourable hand.
. Will whisper music to my weary Spirit.
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. King Henry VI, part II > Act I, scene II

HUME: This they have promised, to show your highness
. A Spirit raised from depth of under-ground,
. That shall make answer to such questions
. As by your grace shall be propounded him.
-----------------------------------------------
. King John > Act IV, scene III
.
ARTHUR: O me! my uncle's Spirit is in these stones:
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If the left front wheel is mired and the right front wheel is being dragged, is Spirit coming down? Why is there no indication of a rut from the left wheel before the soft sinking? Normally one considers the front as being the lead. If so why is there a rut going up toward home plate?

The rover has been driving backwards for going on two years now, since the front wheel failed.

hgldr wrote:Spirit doesn't have the equivalent of 4WD???? One tire is spinning while the other is not??
Don't tell me that the engineers for the motor control system were incapable of designing a simple synchrounous drive. Why didn't they? I bet the managers didn't let them or they had to perform 1,000's of hours of reliability calculations so that they had no time to design it correctly. That's just pathetic. No, that needs shouting. That's just PATHETIC.

Independent wheeling has advantages, including turning.

They should alternately lift and press down with the outside Turn wheels allowing soft soil to fall in the depressions then alternately compressing this soil and effectively gradually lifting the rover above the sticky point.

http://marsrover.nasa.gov/gallery/press/spirit/
http://www.nasa.gov/mission_pages/mer/s ... pdate.html