[Space] NASA - Mars Exploration Rover MER-A "Spirit" - Update Thread

[Rand]

800 W*ora

Life: messy. Rover: clean! While we prep for extrication testing on Earth, Spirit's solar-array energy has climbed above *800* Watt-hours.

[+Benito+]

W*h

[Rand]

[Rand]

sols 1913-1919, May 21-27, 2009: Recovery Efforts Continue

Spirit remains stationary, pending development of a recovery strategy to free her from the loose, soft terrain on the west side of Home Plate.

The rover continues to conduct extensive remote sensing observations of its local terrain. A 360-degree color panorama, called the Calypso panorama, is being collected, and includes the rover's deck. Additional mini-thermal emission spectrometer (TES) observations have been sequenced. Thanks to the extra energy made possible by recent solar array dust cleaning events, Spirit has been collecting measurements of atmospheric argon almost every day using its alpha-particle X-ray spectrometer (APXS).

The project continues to investigate the left middle wheel stall that occurred back on Sol 1899 (May 6, 2009). A small (4-degree) backward wheel motion test was sequenced on Sol 1913 (May 21, 2009). The wheel and motor performed satisfactorily. A second, larger test (16 degrees) was performed on Sol 1916 (May 24, 2009), and again, the wheel performed satisfactorily, showing no signs of a jam in the backward direction.

Pending the recertification of the robotic arm (the instrument deployment device, or IDD), a microscopic imager (MI) mosaic of Spirit's underbelly is planned for this coming weekend to assess the rover's embedded condition.

On the ground, testing with the surface system testbed (SSTB) rover at JPL is held up due to a computer server disk crash. That server is being restored from a huge backup tape, which is taking considerable time. In parallel, the SSTB-Lite rover (an alternate, lower-fidelity testbed rover) is being set up to conduct early tests of candidate soil simulants.

Spirit is very active, with abundant energy. Once again, Spirit has received a beneficial solar array dust cleaning. Dust factor (a measure of array cleanliness) improved about 10 percent on Sol 1918 (May 26, 2009). As of Sol 1919 (May 27, 2009), solar array energy production was 843 watt-hours, enough to run a 100-watt bulb for more than eight hours, with atmospheric opacity (tau) around 0.606. The dust factor increased to 0.774, meaning that about 77.4 percent of the sunlight hitting the solar array penetrates through the dust on the array.

Spirit's total odometry as of Sol 1919 (May 27, 2009) is 7,729.93 meters (4.8 miles).

4chr

[Rand]

Usando il Microscopic Imager Spirit ha fotografato la sua "pancia" (l'immagine è fuori fuoco a causa delle caratteristiche dello strumento):

Spirit took its first set of images of the ground beneath it on Saturday. It kept its arm a conservative distance away from the ground to avoid hitting the surface, but the resulting pictures were too out-of-focus to show much.

On Tuesday, Spirit's arm moved in to take a closer look and did not see any obvious sign that rocks were pushing up on the rover's belly. "It certainly doesn't look like the rover is bearing its weight on a mound of rocks, which was one of our early concerns," Callas told New Scientist.

The images did reveal one possible obstruction – a rock or mound of dirt near the middle of the rover. But it is not clear whether the object is actually touching the rover's belly. "We can't tell if it's underneath the lowest part of the belly pan or in front of it," Callas says. The team plans to take pictures at different angles to get a better sense of the shape and location of the obstruction.

In the meantime, the team is preparing a test-bed at JPL to simulate conditions on the Red Planet. Team members are currently looking for a substance that can simulate the Martian soil beneath Spirit (see How to make a Martian mud pie).

[Rand]

Shoot! Someone tripped on the camera cable in Sound Stage 25 again! I told them to put some duct tape on it. Thanks for point me to it. I will make some phone calls.

Paolo

[+Benito+]

Ma quindi? Sta andando in vacca?

[Rand]

Paolo Bellutta, Scott Maxwell (il guidatore di rover che scrive Mars and Me) e Kim Lichtenberg sono partiti in macchina e si sono procurati una ventina di Kg di farina fossile ad uso alimentare che gli serve per simulare il terreno dove è insabbiato Spirit:

During the investigation of this anomaly there are intense moments but also amusing ones. I want to share one with you. As soil simulant we are settling on a mix of diatomaceous earth and clay. Apparently there is a "food grade" DE used to deworm animals and as insecticide (among other things). Scott Maxwell, kim Lichtenberg and I hopped on a car and drove down to Lake Elsinore where there is a facility that sells food grade DE in bulk to get a small sample for testing.

Unfortunately I do not have pictures: the transaction of purchasing a 50lb bag of fine white powder happened at a gas station near a freeway exit.

Paolo

Queste persone che si scambiavano sacchetti di roba bianca in un area di servizio non devono aver fatto un ottima impressione

Originariamente inviato da +Benito+

Ma quindi? Sta andando in vacca?

Visto che ci scherzano sopra direi che sono solo dati arrivati parzialmente corrotti per un qualche motivo "normale".

[il Caccia]

qualche novità? ci sono speranze?

[Rand]

Originariamente inviato da il Caccia

qualche novità? ci sono speranze?

Stanno facendo delle prove nella "sandbox" (in parole povere è dove dove simulano il terreno di Marte e possono fare dei test per vedere come si comporta il rover) del JPL per determinare l'approccio migliore. Comunque ci vorrà ancora del tempo (a occhio almeno 2 o 3 settimane, forse di più) visto che vogliono essere ragionevolmente sicuri di non peggiorare la situazione invece di risolverla..

[Rand]

In attesa che si finisca di sviluppare e testare una tecnica per disinsabbiare Spirit si farà uso dell'energia sovrabbondante per effettuare osservazioni notturne del cielo:

Amazingly, we're planning *overnight* observations on Spirit. We've got *that* kind of energy. Stay tuned for PANCAMs of the night sky

[jumpjack]

Originariamente inviato da Rand

In attesa che si finisca di sviluppare e testare una tecnica per disinsabbiare Spirit si farà uso dell'energia sovrabbondante per effettuare osservazioni notturne del cielo:

Da non credere, ora abbiamo un robot IN VACANZA su marte che passa il tempo... sdraiato sulla sabbia a guardare le stelle!!!
E intanto a casa che chi si fa un mazzo tanto per riuscire a tirarlo fuori dalle... sabbiature!!!

[Rand]

[Rand]

Qualche buona notizia:

NASA readies 'sandbox' to plot Mars rover's escape

NASA plans to fill a 'sandbox' with simulated Martian soil this week to test escape manoeuvres for the Mars rover Spirit, which has been stuck in a sand trap called "Troy" since early May.

When the rover first became stuck, its wheels slipped so much in the fine, flour-like soil that Spirit moved just centimetres despite the fact that its wheels had rotated enough to move it about 10 metres away. Mission managers then stopped trying to drive the rover, whose wheels had already become buried halfway into the loose soil.

NASA now hopes to begin testing possible escape strategies this week, using a mock-up of the sand trap.

To simulate the conditions at Spirit's site, the rover team will use a cement mixer to combine several tonnes of clay and diatomaceous earth, a type of chalk-like rock made of the fossilised remains of diatoms, algae with cell walls made of silica. The team may also add sand to the mix.

A similar cocktail was used to test escape strategies for Spirit's twin, Opportunity, which was trapped for about five weeks in 2005 on a 30-centimetre-high ripple of soil, nicknamed "Purgatory Dune".

Once the simulated Martian soil is ready, the mixture will be shovelled into a test bed at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. It will then be landscaped to match the tilted terrain at Spirit's site, which is largely responsible for the fact that the rover is currently tilted by about 14 ° to the left.

Driving techniques

Engineers will then embed a model rover in the simulated Martian soil and used it to test escape manoeuvres. "What we want to do is run through the whole spectrum of possibilities in the test bed to see which one would work," says John Callas, the rover project manager at JPL.

The driving will likely consist of variations on two basic techniques: driving Spirit straight out of the sand pit and turning its wheels so that the rover moves sideways downslope, Callas says. If all goes well, NASA may begin commanding Spirit to move by mid-July.

Some of the team's worst fears seem to have abated since May, when mission members worried the rover might be so deeply embedded that its belly might actually be resting on rocks it had spotted earlier from a distance.

That could have meant there was not enough weight pressing down on the wheels to give them the traction needed for an escape.

Barely touching

But images taken using the microscopic imager on the end of Spirit's robotic arm in early June revealed a single, pointy object on the ground beneath the rover's belly. Further analysis suggests the rock-like object is just barely touching the underside of the rover but is not bearing any weight.

The rock also appears to be resting on top of the Martian soil, suggesting Spirit might be able to press it further into the ground if it does come into contact with the rock. "When we do start to move [Spirit], it's likely that rock won't be a hazard or obstruction. Right now it's a concern, but it's not considered a serious concern," Callas told New Scientist.

Another worry was Spirit's left-middle wheel, which seemed to have been jammed by another rock. But the wheel now seems to be rotating freely, suggesting the obstruction is gone. Callas says the team will proceed cautiously in case further churning of the soil causes the suspected rock to fall back in.

[+Benito+]

Fossi in loro studierei bene la possibilità di sollevare le gambe sotterrate appoggiando il robot sulla roccia sotto la pancia.

[Rand]

Se si appoggia la pancia, il peso del rover non è più sulle ruote. E' una situazione che vogliono evitare perché se succede c'è il serio rischio che le ruote non facciano più grip.

[+Benito+]

Originariamente inviato da Rand

Se si appoggia la pancia, il peso del rover non è più sulle ruote. E' una situazione che vogliono evitare perché se succede c'è il serio rischio che le ruote non facciano più grip.

Chiaro che non è più sulle ruote, ma se hai mai tolto una macchina impantanata più le ruote girano più la macchina va giù se c'è su peso.

[Rand]

Indipendentemente dalla correttezza dell'approccio che suggerisci in base alle analisi svolte la roccia non dovrebbe essere in grado di reggere il peso del rover (affonderebbe nel terreno), quindi non è una strada praticabile.

Riguardo alla correttezza a quanto ho capito il tipo di movimento dei rover (lento) non si presta bene ad analogie "automobilistiche". In questa lunga discussione si parla in diffusamente dei vari aspetti dell'insabbiamento.

[Rand]

Sezione dedicata sul sito dei MER.

[Rand]

Mars Rover Yielding New Clues While Lodged in Martian Soil

PASADENA, Calif. -- NASA's Mars rover Spirit, lodged in Martian soil that is causing traction trouble, is taking advantage of the situation by learning more about the Red Planet's environmental history.

In April, Spirit entered an area composed of three or more layers of soil with differing pastel hues hiding beneath a darker sand blanket. Scientists dubbed the site "Troy." Spirit's rotating wheels dug themselves more than hub deep at the site. The rover team has spent weeks studying Spirit's situation and preparing a simulation of this Martian driving dilemma to test escape maneuvers using an engineering test rover at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

A rock seen beneath Spirit in images from the camera on the end of the rover's arm may be touching Spirit's belly. Scientists believe it appears to be a loose rock not bearing the rover's weight. While Spirit awaits extraction instructions, the rover is keeping busy examining Troy, which is next to a low plateau called Home Plate, approximately 3.2 kilometers (2 miles) southeast of where Spirit landed in January 2004.

"By serendipity, Troy is one of the most interesting places Spirit has been," said Ray Arvidson of Washington University in St. Louis. Arvidson is deputy principal investigator for the science payloads on Spirit and its twin rover, Opportunity. "We are able here to study each layer, each different color of the interesting soils exposed by the wheels."

One of the rover's wheels tore into the site, exposing colored sandy materials and a miniature cliff of cemented sands. Some disturbed material cascaded down, evidence of the looseness that will be a challenge for getting Spirit out. But at the edge of the disturbed patch, the soil is cohesive enough to hold its shape as a steep cross-section.

Spirit has been using tools on its robotic arm to examine tan, yellow, white and dark-red sandy soil at Troy. Stretched-color images from the panoramic camera show the tints best.

"The layers have basaltic sand, sulfate-rich sand and areas with the addition of silica-rich materials, possibly sorted by wind and cemented by the action of thin films of water. We're still at a stage of multiple working hypotheses," said Arvidson. "This may be evidence of much more recent processes than the formation of Home Plate...or is Home Plate being slowly stripped back by wind, and we happened to stir up a deposit from billions of years ago before the wind got to it?"

Team members from NASA's Johnson Space Center in Houston feel initial readings suggest that iron is mostly present in an oxidized form as ferric sulfate and that some of the differences in tints at Troy observed by the panoramic camera may come from differences in the hydration states of iron sulfates.

While extraction plans for the rover are developed and tested during the coming weeks, the team plans to have Spirit further analyze the soil from different depths. This research benefits from having time and power. In April and May, winds blew away most of the dust that had accumulated on Spirit's solar panels.

"The exceptional amount of power available from cleaning of Spirit's solar arrays by the wind enables full use of all of the rover's science instruments," said Richard Moddis of the Johnson team. "If your rover is going to get bogged down, it's nice to have it be at a location so scientifically interesting."

The rover team has developed a soil mix for testing purposes that has physical properties similar to those of the soil under Spirit at Troy. This soil recipe combines diatomaceous earth, powdered clay and play sand. A crew is shaping a few tons of that mix this week into contours matching Troy's. The test rover will be commanded through various combinations of maneuvers during the next few weeks to validate the safest way to proceed on Mars.

Spirit's right-front wheel has been immobile for more than three years, magnifying the challenge. While acknowledging a possibility that Spirit might not be able to leave Troy, the rover team remains optimistic. Diagnostic tests on Spirit in early June provided encouragement that the left-middle wheel remains useable despite an earlier stall.

"With the improved power situation, we have the time to explore all the possibilities to get Spirit out," said JPL's John Callas, project manager for Spirit and Opportunity. "We are optimistic. The last time Spirit spun its wheels, it was still making progress. The ground testing will help us avoid doing things that could make Spirit's situation worse."

Images and further information about Spirit and Opportunity are available at: http://marsrovers.jpl.nasa.gov and http://www.nasa.gov/rovers .