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Deep Space Digest – June 6
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Venus Express encounters resistance, Opportunity studies dirt, Rosetta approaches its target, Cassini bounces radio waves off Titan, and New Horizons does a dry run.

In the News:

 

Venus Express

Venus Express continued the ‘walk-in’ phase of its Venus aerobraking campaign. On May 27, the ESA reported that Venus’s atmospheric density was slightly higher than expected, leading to a reboost to slow the probe’s descent. Otherwise, things continue as planned for the aerobraking campaign, which is still expected to begin on June 17.

Time since launch: 3132 days
Time elapsed time in Venus orbit: 2979 days
Light travel time to Earth: 10 minutes, 19 seconds

 

Opportunity

The general area that Opportunity is studying has been named Pillinger Point after Colin Pillinger, head scientist on the failed 2003 Beagle 2 mission. He died on May 7 of a brain hemorrhage, two days before his 71st birthday. At Pillinger Point, Opportunity has been busy studying clay minerals that appear to have been deposited in freshwater. Much of its time has been performing mineralogical studies with its Alpha Particle X-ray Spectrometer (APXS). Targets include a vein of light-colored rock named Bristol Well and another target named Sarcobatus Flat. On evenings when the rover is not performing mineralogical studies with the APXS, it uses the instrument to measure atmospheric argon levels.

NASA continues to update Opportunity’s internal clock by approximately 1 second each sol. Although the rover is in generally good health, with plenty of power feeding its solar arrays, it did experience a flash memory reset overnight on May 25. The problem is intermittent, and appears to be an annoyance rather than a danger to the survival of the rover.

Time since launch: 3988 days
Total elapsed time on Mars: 3684 sols (3785 Earth days)
Total roving distance: 39.41km (24.49 miles)
Light travel time to Earth: 6 minutes, 52 seconds

 

Rosetta

On June 4-5, Rosetta performed the second “Big Burn”, a maneuver designed to slow down the probe’s velocity relative to 67P/Churyumov-Gerasimenko. This thruster burn took over 6 1/2 hours to complete and used 196kg of propellant to change the probe’s velocity by ~270 m/s. The burn was necessary to slow the closing speed of 67P, which is rapidly catching up to Rosetta from behind. With this burn, Rosetta has completed three of the eight major burns needed to position itself for orbital insertion around 67P in August. Rosetta is now less than 400,000 km (248,000 mi) from the comet, or around the average separation of the Earth and Moon.

Time since launch: 3749 days
Current distance from 67P/Churyumov-Gerasimenko: 380,000km (239,000 miles)
Current distance from Earth: 461 million km (287 million miles); light travel time: 25 minutes 38 seconds

 

Cassini

From May 16 to May 20, Cassini spent much of its time observing Titan. As it approached the moon, it spent much of its time observing Alkaid, the star on the end of the Big Dipper’s handle. Titan passed in front of Alkaid as seen from Cassini, turning the star into a tool that can be used to gauge the properties of Titan’s atmosphere. Using its ultraviolet spectrometer, Cassini measured changes in the star’s light, allowing scientists on Earth to construct a high-resolution profile of the atmosphere’s chemistry and density.

During the flyby, Cassini performed a radio science experiment. A visualization of this experiment can be seen here. As Cassini skimmed Titan’s surface as seen from Earth, it sent radio transmissions through Titan’s atmosphere. Some of these transmissions bounced off the surface of Titan before being received on Earth. By measuring how much the waves are scattered when they bounce, scientists can figure out some of the basic properties of Titan’s surface over a much wider area than was possible with the Huygens lander.

The maneuvers performed for the radio science experiment changed Cassini’s orbit, shortening it from 36 to 32 days and making it more steeply inclined to Saturn’s equator. Although this change was planned, small variations in Titan’s gravity meant that Cassini required a short (13 second) course correction maneuver to put it on the proper trajectory. Cassini’s orbit brings it high over Saturn’s poles, which give it a bird’s-eye view of Saturn’s auroras. On May 14 and 15, Cassini observed auroras over Saturn’s south pole, and on May 21, 22, 24 and 29th it observed auroras over Saturn’s north pole.

Time since launch: 6079 days
Total time at Saturn: 3628 days
Light travel time: 1 hour, 14 minutes

 

New Horizons

On May 29-30, New Horizons performed a test of its Pluto flyby sequence. Not all of the spacecraft’s instruments can be pointed in the same direction at the same time due to the need to balance New Horizons’ rotational axis. The flyby sequence is a carefully choreographed program that tells New Horizons where to be pointing and when, allowing its array of instruments to perform observations. The test was a full dress rehearsal, which involved taking pictures, making environmental observations, and communicating with Earth. The data from the test will be transmitted back to Earth, allowing the New Horizons team to find any problems with the sequence well ahead of its flyby of Pluto on July 14, 2015. Once the data is downlinked, New Horizons will be put back into hibernation until early next year.

Time since launch: 3061 days
Current distance from Pluto: 514 million kilometers (319 million miles)
Current distance from Earth: 4.28 billion kilometers (2.66 billion miles); light travel time: 3 hours, 58 minutes

 

Other missions:

 

MESSENGER

MESSENGER is in its last year of operation at Mercury. End of Mission is slated for sometime mid-2015.

Time since launch: 3594 days
Total elapsed time in Mercury orbit: 1177 days
Light travel time to Earth: 5 minutes, 16 seconds

 

Chang’e 3/Yutu

No news on Chang’e 3 and Yutu this update. The sun was down at the landing site at Mare Imbrium, so the two would have spent the period in hibernation.

Time since launch: 188 days
Time since landing: 175 days

 

MAVEN

Currently en route to Mars, which it is expected to reach September 22, 2014.

Time since launch: 200 days
Current distance from Mars: 28.8 million kilometers (17.9 million miles)
Current distance from Earth: 96.2 million kilometers (59.8 million miles); light travel time: 5 minutes, 20 seconds

 

Mangalyaan-1

On June 2, ISRO released a short statement that Mangalyaan-1 was in good health, and may perform a small course correction maneuver on or around June 11. India’s first Mars mission is currently en route to the Red Planet, which it is expected to reach September 24, 2014.

Time since launch: 213 days
Current distance from Mars: 29.8 million kilometers (18.5 million miles)
Current distance from Earth: 95.9 million kilometers (59.6 million miles); light travel time: 5 minutes, 19 seconds

 

Curiosity

After wrapping up geologic work at The Kimberley waypoint, Curiosity is again traveling towards the foot of Mt. Sharp.

Time since launch: 924 days
Total elapsed time on Mars: 652 sols (669 Earth days)
Light travel time to Earth: 6 minutes, 52 seconds

Dawn

Currently en route to the asteroid Ceres, which it is expected to reach in February 2015.

Time since launch: 2445 days
Time since Vesta departure: 640 days
Current distance from Ceres: 11.6 million kilometers (7.2 million miles)
Current distance from Earth: 286 million kilometers (178 million miles); light travel time: 15 minutes 58 seconds

 

Juno

Currently en route to Jupiter, which it is expected to reach in August 2016.

Time since launch: 1031 days
Current distance from Jupiter: 365 million kilometers (227 million miles)
Current distance from Earth: 542 million kilometers (337 million miles); light travel time: 30 minutes, 11 seconds

 

Voyager 1

Time since launch: 13,424 days
Current distance from Earth: 19.02 billion kilometers (11.82 billion miles); light travel time: 17 hours, 37 minutes

 

Voyager 2

Time since launch: 13,440 days
Current distance from Earth: 15.61 billion kilometers (9.70 billion miles); light travel time: 14 hours, 27 minutes

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About The Author
Justin Cowart
Justin Cowart is a geologist interested in Earth and Solar System history. As a geologist, he spends hist time looking at the ground, but in his free time he looks to the skies as an amateur astronomer.

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