To prepare for an actual attempt to extract the Spirit rover from its sand-trapped predicament, engineers using test rovers on Earth have added a new challenge. Until last week, those commanding and assessing drives by the test rovers were usually in the same room as the sandbox setup simulating Spirit’s predicament, where they can watch how each test goes. That changed for the latest preparation, called an operational readiness test.
The team members commanding drives by a test rover last week stayed away from the building with the sandbox. They assessed the results of each commanded drive only from the images and other data communicated from the test rover, the same way the team does for daily operations of the rovers that are on Mars.
“We conducted this round of testing under more flight-like conditions to test the team’s ability to make very complex extraction driving decisions using only the data sent back from the rover,” said Mars Exploration Rover Project Manager John Callas of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
The test began on Oct. 12 and ran five days on an accelerated schedule of two Martian days’ worth of commanding every day. The rover team also operated both Spirit and its twin, Opportunity, while conducting this readiness test at JPL.
Spirit became embedded in soft soil at a site called “Troy” five months ago, more than five years into a mission on Mars that was originally scheduled to last for three months. The rover team suspended further driving attempts with Spirit while evaluating possibilities from tests performed at JPL simulating the Troy situation.
Current plans call for an independent panel to review Spirit driving plans in late October, following analysis of results from the readiness test. Unless that review recommends any further preparations, Spirit will probably begin extraction moves within two weeks after the review.
Spirit has spent much of its time at Troy actively examining its surroundings, including analysis of layered soil at the site. In September, a new issue began affecting operations. Data from Spirit indicated that a brake on the motor that rotates the rover’s dish-shaped high-gain antenna was not working correctly. The team has been getting more diagnostic data and developing a work-around strategy similar to work-arounds already used for rover-motor brakes that showed similar symptoms earlier.
Oh no! Hopefully the same folks who went nuts over the Bigfoot on Mars don’t see this one! Could there really be a dragon on Mars? Relax, its just a shadow from Opportunity’s camera mast, distorted by the unusual and bumpy fusion crust surface of the Shelter Island meteorite that the Mars rover has been studying the past few days. But it seems rather fitting: “Here Be Dragons” is a phrase used to denote unexplored territories, and that is certainly where Oppy and Spirit are in their explorations of Mars.
It’s amazing what a rover can find laying by the side of the road. The Mars Exploration Rover Opportunity has found a rock that apparently is another meteorite. Less than three weeks ago, Opportunity drove away from a larger meteorite called “Block Island” that the rover examined for six weeks. Now, this new meteorite, dubbed “Shelter Island,” is another fairly big rock, about 47 centimeters (18.8 inches) long, that fell from the skies. Block Island is about 60 centimeters (2 feet) across and was just 700 meters (about 2,300 feet) away from this latest meteorite find. At first look, the two meteorites look to be of a similar makeup; Opportunity found that Block Island was is made of nickel and iron.
This image was taken during Oppy’s 2,022nd Martian day, or sol, (Oct. 1, 2009).
See below for a 3-D version of this image created by Stu Atkinson.
About 18 months ago Doug Ellison from UnmannedSpaceflight.com created a flyover of the Columbia Hills on Mars using data from the Mars Reconnaissance Orbiter and Spirit, the Mars rover. He’s now done a 2.0 version to mark Spirit’s recent birthday — she’s been on Mars for 3 Martian years. Ellison made the skies a little hazier to mark the moderate dust storm that occurred recently and put Spirit in her current predicament, stuck in the sandy soil near Home Plate. Additionally, he added music and an intro credit page to avoid it being badly credited, (which happened when it was posted on Astronomy Picture of the Day in May of 2008) as well as a map at the end to show where Spirit has been all this time. If you saw the first version, this one is even better. If you haven’t seen it before, prepare to be amazed.
Not to leave out Opportunity, below you’ll find some incredible drive mosaics put together by James Canvin, also from UnmannedSpaceflight.com. Oppy is putting the pedal to the metal to reach Endeavour Crater and is covering a lot of territory these days.
This looks like a very interesting location, with rocks and scarps and all sorts of interesting stuff littering the dunes. James told me this mosaic was created with three different images and colorized by using R21 filters (red & blue then with artifical green made by mixing the two).
Canvin told me that the crater near the center-left, off in the distance, is Nautilus. The rocks in the near-field are the surroundings to Nereus crater to which is Oppy was right next to and is out of frame to the left. The rover has already driven in the direction of the center of the image (this is a ‘drive direction’ mosaic after all!), and a much larger mosaic of this is still being downlinked from the rover, which should be even more spectacular.
The Spirit rover has been stuck in loose soil on Mars for several months now, and just as the rover team is preparing to execute maneuvers to attempt to free Spirit, a dust storm hits. Is Mars an unforgiving planet or what? The amount of electricity generated by the solar panels on Spirit has been declining for the past several Martian days, or sols, because of the storm, and Spirit’s daily activities have been trimmed. Those watching over the rover are keeping an eye on weather reports from observations by NASA’s Mars Reconnaissance Orbiter. While the rover team at JPL are keeping their “spirits” up, a recent image from the rover indicates Spirit herself might be getting frustrated with her string of bad luck:
Thanks to Stuart Atkinson from Cumbrian Sky for his image spoof!
Spirit’s solar panels generated 392 watt-hours during the mission’s Sol 2006 (Aug. 24, 2009), down from 744 watt-hours five sols earlier, but still generous compared with the 240 watt-hours per sol that was typical before a series of panel-cleaning events about four months ago.
“We expect that power will improve again as this storm passes, but we will continue to watch this vigilantly,” said JPL’s John Callas, project manager for Spirit and its twin, Opportunity. “Spirit remains power positive with healthy energy margins and charged batteries. The weather prediction from the Mars Color Imager team is that the storm is abating, but skies will remain dusty over Spirit for the next few sols.”
Recent images from the Mars Color Imager camera on Mars Reconnaissance Orbiter showed this regional storm becoming less extensive Monday even as it shifted southward so that its southern edge covered the Gusev Crater area where Spirit is working. Malin Space Science Systems in San Diego, which operates that camera, provides frequent weather updates to the rover team. Check out weekly weather reports here.
Meanwhile, in JPL’s In-Situ Instrument Laboratory, the rover team is continuing testing of strategies for getting Spirit out of a patch of soft soil where it is embedded on Mars. On Sol 2005 (Aug. 23, 2009) Spirit used its panoramic camera to examine the nature of how soil at the site has stuck to the rover’s middle wheels. The team has also used Spirit’s rock abrasion tool as a penetrometer to measure physical properties of the soil around Spirit by pressing into the soil with three different levels of force. The team is aiming to start sending drive commands to Spirit in September.
Another milestone for the Mars Exploration Rovers: Spirit has been operating on Mars for 2000 sols, or Martian days. Who would have ever thought the rovers would last this long? But here they are, still going, um, pretty strong. Even though she’s got plenty of electrical power, Spirit is currently stuck in loose soil at her location, called Troy. But engineers are working hard to figure out how to set her free. Check out the latest on the efforts at the Free Spirit website.
One of the great things about the Mars Exploration Rovers is that we get to see these scrappy little vehicles ramble across the surface of Mars, and watch science in action. Case in point: the meteorite found by Opportunity, dubbed “Block Island.” Scientists are debating all sorts of things about this watermelon-sized rock. How old is it? What is it made of? Where could it have come from? But not only are we learning about this alien rock, we’re also learning about the Red Planet itself and its environmental history.
See below for a new 3-D version of Block Island created by Stu Atkinson.
Scientists calculate Block Island is too massive to have hit the ground without disintegrating unless Mars had a much thicker atmosphere than it has now when the rock fell. An atmosphere slows the descent of meteorites, and with today’s thin Martian atmosphere, this heavy rock would have plummeted to the surface.
Block Island is approximately 60 centimeters (2 feet) in length, half that in height, probably weighs about a half ton, and has a bluish tint that distinguishes it from other rocks in the area.
Opportunity found a smaller iron-nickel meteorite, called “Heat Shield Rock,” in late 2004. Block Island is roughly 10 times as massive as Heat Shield Rock and several times too big to have landed intact without more braking than today’s Martian atmosphere could provide.
“Consideration of existing model results indicates a meteorite this size requires a thicker atmosphere,” said rover team member Matt Golombek of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Either Mars has hidden reserves of carbon-dioxide ice that can supply large amounts of carbon-dioxide gas into the atmosphere during warm periods of more recent climate cycles, or Block Island fell billions of years ago.”
Additional studies also may provide clues about how weathering has affected the rock since it fell.
“There’s no question that it is an iron-nickel meteorite,” said Ralf Gellert of the University of Guelph in Ontario, Canada. Gellert is the lead scientist for the rover’s alpha particle X-ray spectrometer, an instrument on the arm used for identifying key elements in an object. “We already investigated several spots that showed elemental variations on the surface. This might tell us if and how the metal was altered since it landed on Mars.”
The microscopic imager on the arm revealed a distinctive triangular pattern in Block Island’s surface texture, matching a pattern common in iron-nickel meteorites found on Earth.
“Normally this pattern is exposed when the meteorite is cut, polished and etched with acid,” said Tim McCoy, a rover team member from the Smithsonian Institution in Washington. “Sometimes it shows up on the surface of meteorites that have been eroded by windblown sand in deserts, and that appears to be what we see with Block Island.”
Spectrometer observations have already identified variations in the composition of Block Island at different points on the rock’s surface. The differences could result from interaction of the rock with the Martian environment, where the metal becomes more rusted from weathering with longer exposures to water vapor or liquid.
“We have lots of iron-nickel meteorites on Earth. We’re using this meteorite as a way to study Mars,” said Albert Yen, a rover team member at JPL. “Before we drive away from Block Island, we intend to examine more targets on this rock where the images show variations in color and texture. We’re looking to see how extensively the rock surface has been altered, which helps us understand the history of the Martian climate since it fell.”
When the investigation of Block Island concludes, the team plans to resume driving Opportunity on a route from Victoria Crater, which the rover explored for two years, toward the much larger Endeavour Crater. Opportunity has covered about one-fifth of the 19-kilometer (12-mile) route plotted for safe travel to Endeavour since the rover left Victoria nearly a year ago.
When your rover has abundant energy but can’t go anywhere, what’s a scientist to do? How about making observations of the evening and night skies on Mars? With the benefit of a boost in electrical power from a wind gust cleaning off her solar panels, the Spirit rover has more energy available than she’s had for a couple of years. But unfortunately, Spirit is stuck in a patch of loose soil in the Home Plate region on Mars. While the engineers at JPL work hard at figuring out how to “Free Spirit” (see the new website dedicated to their efforts) scientists are making observations of her surroundings to aid in the effort to get her out. But there’s also enough power to do additional observations, and astronomy was a logical choice. “Certainly, a month or more ago, no one was considering astronomy with the rovers,” said Mark Lemmon, planetary scientist at Texas A&M University and member of the rover team. “We thought that was done. With the dust cleanings, though, everyone thinks it is better to use the new found energy on night time science than to just burn it with heaters.” Besides, Lemmon added, using all the energy in the daytime might lead to overheating.
The image above was taken on Spirit’s sol 1943 (June 22 on Earth)showing the night sky above her location.
But most of the “stars” in this raw image are not really stars, just hot pixels. “We use long and multiple exposures to make stars stand out,” Lemmon told Universe Today. “We can only see bright stars, looking through the dust, but can pick out most of the major stars in Orion for instance.”
But a star is visible in this image. “That streak in the 1943 images is the bright star Canopus,” said Jim Bell, planetary scientist at Cornell University and lead for the rovers’ Pancam team. “We’re monitoring stars to search for evidence of night-time clouds, fog, and hazes. We’re also occasionally trying to image Earth and Venus as they set in the west after sunset. We’ve had some success, but the twilight sky is so bright we’re still working on tweaking the exposure times.”
Of course, this isn’t the first time Spirit has done astronomy on Mars. She also made night sky observations back in 2005. In an article Bell wrote for Sky and Telescope in 2006 he described Spirit’s astronomy as “stone-knives and bear-skins backyard astronomy–but from Mars!” And certainly, this is exciting to have an additional opportunity to make astronomical observations from the surface of another world.
Bell added that the current astronomy campaign with Spirit has many similarities with the one four years ago, and Lemmon said they are focusing on a few different goals for looking at the twilight and night skies.
“The Canopus images may become a regular occurrence, as a way to monitor dust and/or ice in the sky at night–much as we use Sun images in the day,” Lemmon said. “For something like that, we can pick an aim (Canopus, Orion, etc.) and choose filters. We might use color filters to look for any differences that show up, or the clear filter for the most sensitive measurement. Star exposures can go up to 5.5 minutes (compare to 0.1-0.5 sec for a normal day image). We cannot track stars, so they trail after 10 seconds or so–as you see Canopus doing. In longer exposures, hot pixels and cosmic rays show up as points or cluster of light.”
Lemmon said attempting to image Earth and Venus has been challenging. “We’ve imaged both before, farther from the Sun. They are in the twilight, limiting the exposure we can use, and they are in a “bright” part of the sky.”
Lemmon added his personal favorite right now is actually the twilight imaging — not looking at stars but at how fast the twilight glow fades after sunset. “That is proving to be quite helpful in terms of understanding the distribution of dust in the atmosphere –which is closely tied to how weather works on Mars,” he said.
In 2005, the Pancam team was able to capture images of Mars’ two moons, Phobos and Deimos. “They are much brighter and let us use more filters if desired. We may pick this up again. I’m a fan of eclipse imaging, so we would need several quick images to see how fast the moon fades as sunlight is blocked by dust around Mars.”
The moons should start becoming more visible soon, and Lemmon said they will continue to take more images of Canopus and maybe other star fields. The team is not specifically looking for meteors or the orbiters around Mars, but there’s always the prospect of something fascinating showing up on future images.
“We’ve taken some recent images I hope will have new, interesting things in them,” Lemmon said. “But they are still on board the rover so we’ll have to wait and see what they show later.”
The Spirit rover on has been stuck in Martian soil, going nowhere, but that doesn’t mean she hasn’t been busy or hasn’t been making new discoveries. Just the opposite. Scientists have taken advantage of what could be a bad situation to learn more about the Red Planet’s environmental history. “By serendipity, Troy (the region where Spirit is stuck) is one of the most interesting places Spirit has been,” said Ray Arvidson, deputy principal investigator for the science payloads on the two Mars rovers. “We are able here to study each layer, each different color of the interesting soils exposed by the wheels.”
While the rover team remains optimistic about getting Spirit unstuck, they have also acknowledged the possibility that the rover might not ever be able to leave Troy. But engineers at JPL are pulling out all the stops, and will be conducting test at the Mars Yard with the engineering rover. (More on that below.)
But Spirit is also benefiting from increased power from wind events in April and May that blew away most of the dust accumulated on the rover’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.”
While engineers are working on a plan for getting Spirit extracted from her predicament, scientists have been studying images and data the rover has sent back. 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?”
Water seems to have played a role in the different colors seen at the location, and perhaps differences in tints at Troy observed by the panoramic camera may come from differences in the hydration states of iron sulfates.
Meanwhile back on Earth, 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. 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.”
Here’s a rover update: Spirit remains stuck in her location on the west side of Home Plate, and work continues at JPL for testing on how to extract the rover from being embedded in soft soil. A rock may be underneath Spirit, keeping her from moving, but more images are being taken by the microscopic camera at the end of the robotic arm to try and determine exactly what is going on under and around the rover. But with a boosted power supply, Spirit has also been busy making scientific observations of her surroundings. And one more thing, which would be extremely fun, rover driver Scott Maxwell hinted on Twitter that Spirit has so much power now from a recent wind event that cleared off her solar panels that she may attempt to make overnight observations. So stay tuned for PANCAM images of the Martian night sky!
As of Sol 1932 (June 9, 2009), Spirit’s solar array energy production is at 828 watt-hours. Total odometry remains at 7,729.93 meters (4.80 miles).
Meanwhile over on the other side of the planet, Opportunity continues to drive south on the way to Endeavour crater. On Sol 1906 (June 4, 2009), the rover completed a 69-meter (266-foot) drive due south. Elevated actuator currents with the right-front wheel continue to cause concern. On Sol 1910 (June 8, 2009), the planned drive stopped early because a multi-wheel current limit threshold was exceeded. A diagnostic maneuver on the next sol was successful indicating the cause on the previous sol was due to the elevated right-front wheel motor currents.
A long, backward drive was performed on Sol 1912 (June 10, 2009). Driving backwards is one technique to mitigate the elevated wheel currents. However, wheel currents continued to be elevated after that 72-meter (236-foot) drive. Further resting of the rover’s actuators is being considered.
The plan ahead includes opening the shroud of the miniature thermal emission spectrometer (Mini-TES) to expose the instrument’s dust-contaminated elevation mirror to the environment. This is an attempt to allow the wind environment to clean dust off the mirror.
As of Sol 1912 (June 10, 2009), Opportunity’s solar array energy production is 431 watt-hours. Opportunity’s total odometry is 16,569.05 meters (10.3 miles).