* Astronomy

OPPORTUNITY UPDATE: Getting Closer to 'Victoria Crater' - sol 867-871, July 11, 2006:

Opportunity is healthy. This week, Opportunity continued uplinking its new flight software load and driving toward "Victoria Crater." Opportunity completed three more drives toward the large crater on sols 869 (July 4, 2006), 870 and 871.
As of Sol 870, Opportunity is approximately 115 metres from "Beagle Crater" and about 600 meters from Victoria Crater.

Sol-by-sol summaries:

Sol 867 (July 2, 2006): Opportunity took a panoramic camera tau, which is a measurement of opacity, and then a panoramic camera image of the target referred to as "Austin." The miniature thermal emission spectrometer was used for a sky and ground observation and to investigate the target "McKinney."

Sol 868: The panoramic camera aboard Opportunity was busy this sol, imaging targets McKinney, "Baxter Springs" and "Fort Gibson." The miniature thermal emission spectrometer looked at McKinney, the sky and ground, as well as the calibration target on the rover. The panoramic camera also took a tau before communicating with the Mars Odyssey spacecraft. In the morning, a miniature thermal emission spectrometer drift check was conducted to calibrate the instrument's elevation actuator (to remove any drift).

Sol 869: This sol saw Opportunity on the move again. The rover first took a tau with its panoramic camera, stowed its robotic arm and then drove. After the drive, the rover unstowed its arm and completed post-drive imaging with its panoramic and navigational cameras. The miniature thermal emission spectrometer examined the sky and ground.

Sol 870: Opportunity essentially repeated the previous sol's activities, completing a panoramic camera tau, robotic arm stow, drive, unstow, post-drive imaging and use of the miniature thermal emission spectrometer to examine the sky and ground. A drift check was also conducted on the miniature thermal emission spectrometer's elevation actuator.

Sol 871: The morning of this sol involved using the rover's panoramic camera to do an intensive systematic ground survey. Opportunity also drove again this sol after taking a panoramic camera tau. After the drive was completed, the rover took images with its navigation camera and a tau with the panoramic camera. The miniature thermal emission spectrometer examined the sky and ground. In the morning, the panoramic camera was used to quantify sky brightness in the west and, in the afternoon, another drift check was conducted on the miniature thermal emission spectrometer's elevation actuator.

Odometry total as of Sol 870 (July 5, 2006): 8,421.65 meters.

Sol 867

This imagery from the panoramic camera on NASA's Mars Exploration Rover Opportunity shows the outcrop-rimmed "Beagle Crater" appearing on the horizon as Opportunity approaches it. The top version is vertically stretched to make horizon details easier to see. The lower version has normal proportions. The image is a mosaic of frames taken during Opportunity's 855th Martian day, or sol (June 20, 2006).

Beagle Crater is 35 meters in diameter. The Opportunity science and engineering teams hope to have the rover visit it on the way to "Victoria Crater." Beagle Crater was 310 meters away from Opportunity when this picture was taken. Even at this distance, blocks of ejecta can be seen around the prominent, raised rim of Beagle crater, suggesting that it may be among the youngest craters visited by Opportunity.


Exand (1.4mb, 3868 x 2369)
Credit: NASA/JPL-Caltech/MSSS/Cornell University

When scientists using orbital data calculated that they should be able to detect Victoria's rim in rover images, they scrutinised frames taken in the direction of the crater by the panoramic camera. To positively characterise the subtle horizon profile of the crater and some of the features leading up to it, researchers created this vertically-stretched image (top). The stretched image makes mild nearby dunes look like more threatening peaks, but that is only a result of the exaggerated vertical dimension. This vertical stretch technique was first applied to Viking Lander 2 panoramas by Philip Stooke, of the University of Western Ontario, Canada, to help locate the lander with respect to orbiter images. Vertically stretching the image allows features to be more readily identified by the Mars Exploration Rover science team.

Though difficult to discern without labels, the southeast rim of Victoria Crater is visible, as well as two small craters on the dark "annulus," or ring, around Victoria Crater.

OPPORTUNITY UPDATE: Three Sols of Driving Gain 138 metres - sol 852-858, June 23, 2006:

Opportunity is healthy. The rover has started receiving a new flight software load. It also advanced 138.1 metres toward "Victoria Crater" in three sols of driving and observed outcrop targets. As of sol 855 (June 20) Opportunity was 780 metres from Victoria Crater and about 300 metres from "Beagle Crater."

Engineers are uploading new flight software to both Opportunity and Spirit. The upload process is expected to take several weeks before the new software is installed and used. To expedite this process, the team is gradually increasing the duration of Opportunity's high-gain antenna uplink sessions. No files of the new flight software were uplinked via UHF this week. However, beginning with sol 864 (June 29, 2006), Opportunity will begin receiving flight software files via its daily UHF-band communication window as well as via the X-band high-gain antenna.

Sol-by-sol summaries:

Sol 852 (June 17): Files were loaded for the new flight software via a 20-minute window of communication via the high-gain antenna. Targeted remote sensing with the panoramic camera included an assessment of the clarity of the atmosphere ("tau") and imaging of targets called "Holberg" and "Blixen." The miniature thermal emission spectrometer was used for observations of Holberg, Blixen, sky and ground.

Sol 853: A flight software upload used a 20-minute high-gain antenna window. The rover drove 42.1 metres. Untargeted remote sensing included post-drive imaging by the navigation camera and the panoramic camera, an assessment of tau by the panoramic camera, a check for clouds with the navigation camera, and sky and ground observations with the miniature thermal emission spectrometer.

Sol 854: Another flight software upload was accomplished during a 20-minute high-gain antenna communication window. The panoramic camera checked tau. The navigation camera looked back in the direction toward where sol 853's drive began.

Sol 855: During a 30-minute high-gain antenna session, more of the new flight software was transmitted. Opportunity drove 39.4 metres. The navigation camera and panoramic camera made observations from the new location. The panoramic camera checked tau. The miniature thermal emission spectrometer completed a sky and ground observation.

Sol 856: During a one-hour window, another flight software upload was accomplished. Untargeted remote sensing included a panoramic camera observation of the ground's brightness, a panoramic camera assessment of tau, and a miniature thermal emission spectrometer observation of sky and ground.

Sol 857: More flight software files were uploaded during a 30-minute high-gain antenna window. The rover drove 56.6 metres. Opportunity also conducted a panoramic camera assessment of tau, a panoramic camera calibration, and a miniature thermal emission spectrometer observation of sky and ground.

Sol 858 (June 23, 2006): A two-hour high-gain antenna session allowed for the upload of more flight software updates. The navigation camera looked back in the direction toward where sol 857's drive began. The panoramic camera checked tau and made a calibration observation. The miniature thermal emission spectrometer observed sky and ground.

Opportunity's total odometry as of the end of the drive on sol 855 (June 20, 2006) was 8,190.89 metres.