Now Reading
Deep Space Digest – May 23

Chang’e 4 delays, Opportunity finds clay, Curiosity drills, Rosetta works to meet a comet, Cassini observes auroras, and New Horizons looks for a target.

In the News:


Chang’e 3/Yutu

No news on Chang’e 3 and Yutu this update. The sun was up at the landing site at Mare Imbrium, but as most instruments on the rover have failed, the two spacecraft likely did very little except transmit engineering data. According to a post in the South China Morning Press, the premature failure may have caused a delay and a change in goals for China’s follow-up mission, Chang’e 4. Long Lehao, director of a committee of the Chinese Academy of Launch Vehicle Technology, suggested that Chang’e 4 would attempt to orbit the moon before returning to Earth safely. This would be a test of the technology needed for Chang’e 5, which is currently slated to be a sample return mission.

Time since launch: 174 days
Time since landing: 161 days



Opportunity finally reached an area of clay minerals detected by the Mars Reconnaissance Orbiter on May 8. As it entered the area, the rover checked out targets of opportunity (no pun intended), including sand ripples and small outcrops along its drive path. After arriving Opportunity began performing surveys the numerous small outcrops in the area with its panoramic camera and X-ray spectrometer, searching for clay deposits. On May 13, it went to the largest outcrop in the area to begin detailed study, seen here in a raw image from Opportunity.

The activity seems to have alleviated electrical issues with Opportunity’s right front wheel. During this period, Opportunity drove nearly 250 meters, much of it during drives on May 1 (95m) and May 4 (60m) and May 10 (26m). Wind has continued to clean the rover’s panels off, leaving them nearly spotless. In their most recent update, engineers reported a dust factor of 0.96, with 1 being a completely clean solar array.

On May 6, the rover’s operators began the process of correcting Opportunity’s internal clocks. The rover’s clocks have slowly drifted out of sync with Earth’s clocks over a decade on Mars, and the issue is beginning to affect some of the rover’s subsystems. To ensure the corrections don’t confuse the rover, NASA has to perform small corrections of just a second or two each day over several days.

Time since launch: 3974 days
Total elapsed time on Mars: 3668 sols (3771 Earth days)
Total roving distance: 39.41km (24.49 miles)
Light travel time to Earth: 6 minutes, 10 seconds



Curiosity continued work at the Windjana outcrop at the foot of Mt. Remarkable. After the hole was drilled on May 5, Curiosity fired several shots of its high-powered ChemCam laser into the hole. On May 15, JPL released an image of the drill hole that shows the small scorch marks left by ChemCam. Curiosity also delievered powdered rock to its battery of internal instruments, where it was stored awaiting further analysis with the SAM mass spectrometer during pauses in the rover’s journey to the foot of Mt. Sharp.

After confirming that samples from Windjana had successfully been stored, the rover’s operators announced that Curiosity would begin wrapping up field work at The Kimberley waypoint. Once finished at the waypoint, Curiosity will continue its trek to reach Mt. Sharp.

Time since launch: 910 days
Total elapsed time on Mars: 637 sols (653 Earth days)
Light travel time to Earth: 6 minutes, 10 seconds



Rosetta is closing in on 67P/Churyumov-Gerasimenko, and is now less than 1 million km (621,000 miles) from its target. The main story is a crucial series of thruster burns necessary to line up Rosetta’s orbit with that of 67P. The first of these burns occurred May 7, although this was a small burn to test out Rosetta’s main thrusters after 8 years of hibernation. The first large burn, involving a change in velocity of nearly 300m/s, occurred on May 21. At eight hours long, this was the longest burn in ESA history. The correction burn was also the largest of Rosetta’s braking sequence, but eight additional burns are scheduled between now and August 6, when Rosetta will enter orbit around 67P.

Although Rosetta is still too far from 67P to see the comet’s nucleus directly, it has already made several observations of the comet. Between March 27 and May 6, Rosetta’s main camera, OSIRIS, took a spectacular sequence of images that show the comet beginning to “turn on” as it races towards the Sun. The images were taken as part of a series of observations designed to pin down 67P’s rotation rate. The value obtained by Rosetta, 12.4 hours, is nearly 20 minutes shorter than less accurate observations made from Earth. The rotation rate is extremely important for Rosetta to pin down ahead of the landing of its Philae lander on the comet.

Time since launch: 3735 days
Current distance from 67P/Churyumov-Gerasimenko: 809,000km (502,000 miles)
Current distance from Earth: 494 million km (307 million miles); light travel time: 27 minutes 28 seconds



During this update period, Cassini was flying high over Saturn, inbound from the most distant leg of its roughly 36 day orbit. Cassini’s orbit is inclined 40.7 degrees to Saturn’s axis, making it ideally placed to study Saturn’s high latitudes. On April 30, May 9 and May 13, Cassini spent much of its day studying auroras around Saturn’s poles. Other imaging campaigns during this time period include observations of Titan on May 3, 4 and 7, Saturn’s rings on May 8, and Tethys on May 11.

When Cassini is far from Saturn, there is plenty of time to do prep-work and routine maintenance. On May 2, Cassini mission control tested out the radio subsystems that would be used for the T-101 flyby of Titan on May 17. This experiment involved bouncing radio signals from Cassini off of Titan’s lake before being received on Earth. This experiment will reveal the texture of Titan’s lakes – whether they’re liquid, solid, or somewhere in between. Cassini also received software upgrades to its CIRS instrument on May 6 and 7. Finally, Cassini scientists worked on refining the density profile of Saturn’s upper atmosphere on May 12. This is especially important prep-work for Cassini’s 2017 Proximal Orbits mission, which will take Cassini well inside the inner edge of Saturn’s ring system.

Time since launch: 6065 days
Total time at Saturn: 3614 days
Light travel time: 1 hour, 14 minutes


New Horizons

As New Horizons sails towards a 2015 flyby of Pluto, mission planners discussed the lack of a post-Pluto flyby target. During planning, it was expected that a Kuiper Belt object (KBO) capable of being visited by New Horizons would be found. Unfortunately, no targets were found by the citizen science campaign Ice Hunters. A follow-up ground-based search has been hampered by a combination of bad weather and dense Milky Way star fields behind Pluto. The New Horizons team is scrambling to book time on the already overloaded Hubble Space Telescope, which planners hope will turn up a suitable target. If not, New Horizons will be limited to long-range observations of already known KBOs.

Time since launch: 3047 days
Current distance from Pluto: 497 million kilometers (308 million miles)
Current distance from Earth: 4.28 billion kilometers (2.66 billion miles); light travel time: 3 hours, 58 minutes


Other missions:



Currently orbiting Mercury. MESSENGER is in its last year of operation at the innermost planet from the Sun, with End of Mission slated for sometime mid-2015.

Time since launch: 3580 days
Total elapsed time in Mercury orbit: 1163 days
Light travel time to Earth: 7 minutes, 13 seconds



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

Time since launch: 186 days
Current distance from Mars: 34.0 million kilometers (21.1 million miles)
Current distance from Earth: 79.6 million kilometers (49.5 million miles); light travel time: 4 minutes, 26 seconds



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: 199 days
Current distance from Mars: 35.2 million kilometers (21.9 million miles)
Current distance from Earth: 80.0 million kilometers (49.7 million miles); light travel time: 4 minutes, 26 seconds



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

Time since launch: 2431 days
Time since Vesta departure: 626 days
Current distance from Ceres: 13.0 million kilometers (8.1 million miles)
Current distance from Earth: 264 million kilometers (164 million miles); light travel time: 14 minutes 42 seconds



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

Time since launch: 1017 days
Current distance from Jupiter: 375 million kilometers (233 million miles)
Current distance from Earth: 505 million kilometers (314 million miles); light travel time: 28 minutes, 10 seconds


Voyager 1

Time since launch: 13,410 days
Current distance from Earth: 19.00 billion kilometers (11.81 billion miles); light travel time: 17 hours, 36 minutes


Voyager 2

Time since launch: 13,426 days
Current distance from Earth: 15.61 billion kilometers (9.69 billion miles); light travel time: 14 hours, 27 minutes

Like this article? Share it with your friends!
What's your reaction?
Love it!
Could be better.
Hate it!
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.

Leave a Response