* Astronomy

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RE: Mars Exploration Rover Spirit

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SPIRIT UPDATE: Spirit Continues Work on Winter Panorama - sol 1657-1662, August 31-September 05, 2008:

Spirit continues to conserve power during the waning Martian winter while performing light science activities. As power permits, Spirit continues to acquire the individual frames of an image mosaic known as the "Bonestell panorama," which will portray a full-colour view of the rover's winter outpost.
Spirit is healthy, with all subsystems performing as expected as of the most recent report from Mars sent by NASA's Odyssey orbiter on sol 1658 (Sept. 1, 2008). Solar-array energy had increased slightly from 235 to 245 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour). Tau -- a measure of atmospheric opacity caused by suspended dust -- dropped from 0.274 to 0.218, meaning the skies were slightly clearer.

Sol-by-sol summary:
In addition to taking daily measurements of dust-related changes in atmospheric opacity (tau), Spirit completed the following activities:

Sol 1657 (Aug. 31, 2008): Spirit acquired column 13, part 1 of the so-called "Bonestell panorama" of the rover's winter surroundings, using all 13 colour filters of the panoramic camera.

Sol 1658: Spirit relayed data from Mars to NASA's Odyssey orbiter to be transmitted to Earth.

Sol 1659: Spirit received new instructions from Earth via the rover's high-gain, X-band antenna.

Sol 1660: Spirit recharged the batteries.

Sol 1661: Spirit recharged the batteries.

Sol 1662 (Sept. 5, 2008): Spirit recharged the batteries.

Odometry:
As of sol 1658 (Sept. 1, 2008), Spirit's total odometry remained at 7,528.0 metres.

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Southern Half of Spirit's 'Bonestell' Panorama

Credit: NASA/JPL/Cornell

This 180-degree panorama shows the southward vista from the location where Spirit is spending its third Martian winter inside Mars' Gusev Crater. The rover's overwintering location is on the northern edge of a low plateau informally called "Home Plate," which is about 80 meters or 260 feet in diameter.

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SPIRIT UPDATE: Waiting Out the Winter - sol 1628-1634, August 01-07, 2008:

Spirit's battery levels are slowly edging upward, thanks to a slight decrease in atmospheric dust (Tau) and a gradual increase in sunlight as winter gives way to spring.
Early in the week, Spirit spent two Martian days carrying out contingency plans following a temporary delay in data transmission from Earth. Spirit implemented the so-called "runout" portion of an earlier master sequence on sols 1628 and 1629 (Aug. 1-2, 2008). Subsequent relays of new instructions from Earth on sols 1629 and 1632 (Aug. 2 and Aug. 5, 2008) went off without a hitch.
Spirit remains healthy, with all subsystems performing as expected as of sol 1630 (Aug. 3, 2008).

Sol-by-sol summary:
In addition to using the panoramic camera to make daily measurements of dust-related changes in atmospheric clarity, Spirit completed the following activities:

Sol 1628 (Aug. 1, 2008): Spirit implemented the runout portion of the master sequence of commands already on board the rover.

Sol 1629: Upon awakening, Spirit continued to implement the runout portion of the master sequence sent earlier. Spirit then received new instructions directly from Earth via the rover's high-gain antenna.

Sol 1630: Spirit acquired column 13 of the "Bonestell panorama" using all 13 color filters of the panoramic camera. The rover relayed fresh data from Mars at UHF radio frequencies to NASA's Odyssey orbiter to be transmitted to Earth.

Sol 1631: Spirit recharged the batteries.

Sol 1632: Spirit received new instructions from Earth via the rover's high-gain antenna.

Sol 1633: Spirit acquired six freeze frames for a time-lapse movie in search of Martian clouds using the navigation camera. The rover took spot images of the sky for calibration purposes with the panoramic camera and monitored dust on the panoramic-camera mast assembly.

Sol 1634 (Aug. 7, 2008): Spirit transmitted fresh data to Odyssey to be relayed to Earth.

Odometry:
As of sol 1634 (Aug. 7, 2008), Spirit's total odometry remained at 7,528.0 metres.

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SPIRIT UPDATE: With Batteries Charged, Spirit is Ready for More Science - sol 1621-1627, July 25-31, 2008:

Spirit has fully recovered from a recent rundown in battery power. Energy has improved to levels not seen since sol (Martian day) 1604 (July 7, 2008). The hit in battery energy was primarily the result of data transmissions taking place later in the day, when less solar energy was available.
During the past week, rover planners eliminated the late communications sessions. Spirit is not scheduled to have another one until sol 1636 (Aug. 9, 2008). To mitigate the impact that one will have on power, rover planners plan to shorten the duration of data transmission from 20 minutes to only 10 minutes. This will allow sufficient time to get new instructions on board the rover while minimizing battery drain.
A transmitter problem thwarted data transmission on sol 1625 (July 29, 2008). The uplink from Earth was to have loaded activity plans and maintenance instructions for sols 1626, 1627, 1628 and 1629 (July 30-Aug. 2, 2008). The sequences already on board Spirit were designed with built-in contingency plans to handle just such an event. As a result, while Spirit continues the "runout" portion of the earlier master sequence, rover operators will send a new set of commands for sols 1630, 1631 and 1632 (Aug. 3-5, 2008) on sol 1629 (Aug. 2, 2008).
Spirit remains healthy, with all subsystems performing as expected as of sol 1626.

Sol-by-sol summary:
In addition to using the panoramic camera to make daily measurements of dust-related changes in visibility, Spirit completed the following activities:

Sol 1621 (July 25, 2008): Spirit recharged the batteries.

Sol 1622: Spirit received instructions from Earth via the rover's high-gain antenna and relayed data to NASA's Odyssey orbiter via the rover's UHF antenna.

Sol 1623: Spirit acquired images of sand formations with the rear hazard-avoidance and navigation cameras. The rover took six, time-lapse, movie frames in search of clouds with the navigation camera, as well as images of the sky (called "sky flats") for calibration purposes.

Sol 1624: Spirit recharged the batteries.

Sol 1625: Spirit took spot images of the sky for calibration purposes with the panoramic camera and acquired movie frames in search of clouds with the navigation camera.

Sol 1626: Spirit completed a horizon survey with the panoramic camera and relayed data to Odyssey for transmission to Earth.

Sol 1627 (July 31, 2008): Spirit recharged the batteries.

Odometry:
As of sol 1626 (July 30, 2008), Spirit's total odometry remained at 7,528.0 metres.

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Image taken by the Spirit rover on Sol 1630

Spirit Sol 1630

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Credit NASA

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SPIRIT UPDATE: Biding Time - sol 1594-1600, June 27-July 03, 2008:

Spirit continues to ride out the Martian winter by doing minimal activities to conserve power. The rover conducts very light science activities every three to four Martian days, or sols, and relays data to NASA's Odyssey orbiter for transmission to Earth every 4 sols. The rest of the time, Spirit mostly sleeps.
As it has been some time since Spirit's operators were able to synchronise the spacecraft clock to Earth time, they wished to determine how far the spacecraft clock had drifted (how much it had changed over time). Synchronization of the clock is a process that requires a power-intensive, two-way, X-band communications link. When the power situation allowed it, they decided to perform an X-band "beep" (a five-minute, low-gain communication session) to estimate the amount of drift. The transmission of plans to do so on sol 1594 (June 27, 2008) were not detected by the ground station. Engineers hoped to make another attempt on sol 1604 (July 7, 2008).
Spirit is healthy and all subsystems were performing as expected as of the Odyssey downlink on sol 1598 (July 1, 2008). Solar-array energy has been steady within the range of 225 watt-hours to 230 watt-hours (100 watt-hours is the amount of energy needed to light a 100-watt bulb for one hour).

Sol-by-sol summary:
During the past week, Spirit completed the following activities:

Sol 1594 (June 27, 2008): Plans called for Spirit to perform a five-minute "beep" at X-band frequencies after relaying data to Earth via the Odyssey orbiter.

Sol 1595: Spirit recharged the battery and measured atmospheric dust opacity, known as Tau, using the panoramic camera.

Sol 1596: Spirit recharged the battery and measured atmospheric dust opacity with the panoramic camera.

Sol 1597: Spirit recharged the battery and measured atmospheric dust opacity with the panoramic camera.

Sol 1598: Spirit received new instructions from Earth via the rover's high-gain, X-band antenna and relayed data to Odyssey at UHF frequencies for transmission of the latest Martian data to Earth. The rover measured atmospheric darkness caused by suspended dust particles with the panoramic camera.

Sol 1599: Spirit conducted light remote sensing.

Sol 1600 (July 3, 2008): Spirit recharged the battery and again measured atmospheric dust with the panoramic camera.

Odometry:
As of sol 1598 (July 1, 2008), Spirit's total odometry remained at 7,528.0 meters.

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SPIRIT UPDATE: New Tricks for an Old Rover - sol 1574-1579, June 6-12, 2008:

To conserve energy and protect one of the on-board spectrometers, spacecraft operators have established the first major change to planning for the Mars Exploration Rover mission since the end of the primary mission, which lasted for 90 days in early 2004.
Spirit's scientists have declared that their highest priority for the winter is preserving the miniature thermal emission spectrometer, an instrument that identifies minerals in rocks from a distance. To do this, the rover heats the instrument overnight and into the morning of every sol. These heaters have been running longer as winter temperatures have dropped and are now averaging about 55 watt-hours per sol.
Heating for Spirit's batteries has increased as well and is now averaging 29 watt-hours per sol. Together, the two heaters account for 84 watt-hours or about 37 percent of Spirit's total energy usage. Everything else, including on-board computers and memories, radios, cameras, sensors and actuators, gets by on about 140 watt-hours -- enough energy to run a microwave oven for a scant 7 minutes.
In response, rover operators have further reduced Spirit's activity levels. The rover now transmits data to Odyssey to be relayed to Earth only every fourth sol. Instead of spending 20 minutes each sol using the rover's high-gain antenna to listen for new instructions from Earth, Spirit spends five minutes listening for instructions using the low-gain antenna on all but two sols per week.
Rover operators create new activity plans once a week, on Fridays, that cover seven sols at a time. Because Spirit isn't engaged in activities that require rover operators to have new images or other data for planning, the rover does not have to relay data to Odyssey just before a planning day. Despite changes to multiple procedures and software tools, the transition has been remarkably smooth.

Sol-by-sol summary:

Sol 1574 (June 6, 2008): Spirit recharged the batteries, listened to instructions from Earth for five minutes using the low-gain antenna, measured atmospheric opacity caused by dust using the panoramic camera, and relayed data to the Odyssey orbiter as it passed overhead.

Sol 1575: Spirit recharged the batteries and listened to instructions from Earth for 20 minutes using the high-gain antenna.

Sol 1576: Spirit recharged the batteries, listened to instructions from Earth for five minutes using the low-gain antenna, and measured atmospheric opacity caused by dust using the panoramic camera.

Sol 1577: Spirit recharged the batteries and listened to instructions from Earth for five minutes using the low-gain antenna.

Sol 1578: Spirit recharged the batteries, listened to instructions from Earth for five minutes using the low-gain antenna, measured atmospheric opacity caused by dust using the panoramic camera, and relayed data to Odyssey during the overhead pass of the orbiter.

Sol 1579 (June 12, 2008): Spirit recharged the batteries and listened to instructions from Earth for five minutes using the low-gain antenna.

Odometry:
As of sol 1578 (June 11, 2008), Spirit's total odometry remained at 7,528.0 metres.

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SPIRIT UPDATE: Energy Levels Reach Record Low - sol 1559-1566, May 22-29, 2008:

Energy production reached a record low for Spirit this past week. On Sol 1560 (May 23, 2008), solar array input was 220 watt-hours (enough energy to light a 100-watt bulb for two hours and 12 minutes). On sol 1563, Spirit expended the highest amount of energy yet on running heaters to maintain minimum temperatures for batteries (30.6 watt-hours) and the miniature thermal emission spectrometer (54.0 watt-hours). Activity levels on Spirit have been kept low this week to compensate for the reduced energy production.
As was the case last week, Spirit had insufficient energy to transmit data to Earth each day. As a result, the operations team selected which Martian days, or sols, would be used for data downlinks to Earth.
Uplinks of communications from Earth have also been curtailed. Spirit typically has a daily communications window when the rover wakes up and points its High-Gain Antenna toward Earth and listens for new commands. By passing up on some of these uplink opportunities, the rover is able to stay awake for shorter periods of time each sol. Rover operators still have the ability to send new commands if necessary.
Despite low energy levels, Spirit continues to be in good health. The rover continues to conduct atmospheric observations, especially measurements of atmospheric opacity. As explained in last week's report, these Tau measurements of the amount of dust in the atmosphere provide valuable data for science and operations planning because they affect the amount of solar energy that reaches the rover's solar panels.
All subsystems are performing as expected.

Sol-by-sol summary:
In addition to receiving direct-from-Earth instructions over the rover's high-gain antenna, Spirit completed the following activities:

Sol 1559 (May 22, 2008): Spirit received new commands from Earth, measured atmospheric opacity caused by dust (Tau) with the panoramic camera and sent data to NASA's Odyssey orbiter to be relayed to Earth.

Sol 1560: Spirit again measured atmospheric dust with the panoramic camera and recharged the batteries.

Sol 1561: Spirit received new commands from Earth. The rover measured atmospheric darkness caused by dust with the panoramic camera.

Sol 1562: Spirit recharged the batteries.

Sol 1563: Spirit measured atmospheric dust with the panoramic camera and transmitted data to Odyssey.

Sol 1564: Spirit received new commands from Earth.

Sol 1565: Spirit recharged the batteries.

Sol 1566 (May 29, 2008): Spirit measured atmospheric opacity caused by dust with the panoramic camera and sent data to Odyssey to be relayed to Earth.

Odometry:
As of sol 1566 (May 29, 2008), Spirit's total odometry remained at 7,528.0 metres.

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Flying Over Mars

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