News of the Comet-hunting Rosetta mission

[Mike]

Amazing images and completely different to how I expected a comet to look. I can't wait till the little lander gets dropped.

[Canadian Roger]

I had expected a smoother, almost sand-blasted, surface.

Perhaps when it gets closer, we'll see a surface more like the penitentes I saw above ALMA in Chile.  
http://en.wikipedia.org/wiki/Penitentes#mediaviewer/File:Penitentes_Ice_Formations.png

[Carole]

I remember when we were holding meetings at the school in Chislehurst (while High Elms was being re-built) that one of the scientists working on the Rosetta Mission came to give us a talk on it and brought along bits of material left over from the mission "build". 

I do recall him saying they were going to rendezvous at around Mars/Jupiter distance and land on the comet before it starts putting out dust and gas so it can observe when it does.  Though it seems the comet has already started doing this intermittently.

A fascinating project.

Carole

[Rick]

Rosetta: Landing Site Search Narrows

The European Space Agency's Rosetta mission has chosen five candidate landing sites on comet 67P/Churyumov-Gerasimenko for its Philae lander. Philae's descent to the comet's nucleus, scheduled for this November, will be the first such landing ever attempted. Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.

Choosing the right landing site is a complex process. It must balance the technical needs of the orbiter and lander during all phases of the separation, descent and landing, and during operations on the surface, with the scientific requirements of the 10 instruments on board Philae. A key issue is that uncertainties in navigating the orbiter close to the comet mean that it is possible to specify any given landing zone only in terms of an ellipse - covering up to six-tenths of a square mile (one square kilometer) - within which Philae might land.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-289

[Rick]

NASA Instrument aboard European Spacecraft Returns First Science Results

A NASA instrument aboard the European Space Agency's (ESA's) Rosetta orbiter has successfully made its first delivery of science data from comet 67P/Churyumov-Gerasimenko.

The instrument, named Alice, began mapping the comet's surface last month, recording the first far-ultraviolet light spectra of the comet's surface. From the data, the Alice team discovered the comet is unusually dark -- darker than charcoal-black -- when viewed in ultraviolet wavelengths.  Alice also detected both hydrogen and oxygen in the comet's coma, or atmosphere.

Rosetta scientists also discovered the comet's surface so far shows no large water-ice patches. The team expected to see ice patches on the comet's surface because it is too far away for the sun's warmth to turn its water into vapor.

"We're a bit surprised at just how unreflective the comet's surface is and how little evidence of exposed water-ice it shows," said Alan Stern, Alice principal investigator at the Southwest Research Institute in Boulder, Colorado.

More: http://rosetta.jpl.nasa.gov/news/nasa-instrument-aboard-european-spacecraft-returns-first-science-results

[Rick]

Rosetta and Philae snap selfie at comet

CIVA, the Comet Infrared and Visible Analyser, is one of ten instruments onboard Philae. The CIVA-P part of the instrument comprises seven micro-cameras that will take a 360 degree panoramic image of the landing site at visible wavelengths, once Philae is safely on the surface of 67P/C-G, including a section in stereo. CIVA-M is a visible/infrared microscope imager/spectrometer that will the study the composition, texture, and albedo of surface samples.

More: http://rosetta.jpl.nasa.gov/news/rosetta-and-philae-snap-selfie-comet

[mickw]

Comet Churyumov-Gerasimenko

Today's APOD

http://apod.nasa.gov/apod/ap140915.html

[Rick]

First Map of Rosetta's Comet

Scientists have found that the surface of comet 67P/Churyumov-Gerasimenko -- the target of study for the European Space Agency's Rosetta mission -- can be divided into several regions, each characterized by different classes of features. High-resolution images of the comet reveal a unique, multifaceted world.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-308

[Rick]

'J' Marks the Spot for Rosetta's Lander

The European Space Agency's Rosetta's lander, Philae, will target Site J, an intriguing region on comet 67P/Churyumov-Gerasimenko that offers unique scientific potential, with hints of activity nearby, and minimum risk to the lander compared to the other candidate sites. The 220-pound (100-kilogram) lander is scheduled to reach the surface on November 11, where it will perform in-depth measurements to characterize the nucleus. Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.

Site J is on the "head" of the comet, an irregular shaped world that is just over 2.5 miles (four kilometers) across at its widest point. The decision to select Site J as the primary site was unanimous. The backup, Site C, is located on the "body" of the comet.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-310

[Rick]

Rosetta to Deploy Lander on November 12

The European Space Agency's Rosetta mission will deploy its lander, Philae, to the surface of comet 67P/Churyumov-Gerasimenko on Nov. 12.

Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.

Philae's landing site, currently known as Site J, is located on the smaller of the comet's two "lobes," with a backup site on the larger lobe. The sites were selected just six weeks after Rosetta's Aug. 6 arrival at the comet, following the spacecraft's 10-year journey through the solar system.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-326

[Mike]

This video gives a nice overview of how Philae will land and what it will do when it gets there:

VIDEO

[Rick]

Rosetta Comet Fires Its Jets

The four images that make up a new montage of comet 67P/Churyumov-Gerasimenko were taken on September 26, 2014 by the European Space Agency's Rosetta spacecraft. At the time, Rosetta was about 16 miles (26 kilometers) from the center of the comet.

In the montage, a region of jet activity can be seen at the neck of the comet. These jets, originating from several discrete locations, are a product of ices sublimating and gases escaping from inside the nucleus.

The overlapping and slightly dissimilar angles of the four images that compose the montage are a result of the combined effect of the comet rotating between the first and last images taken in the sequence (about 10 degrees over 20 minutes), and the spacecraft movement during that same time.

More: http://www.jpl.nasa.gov/news/news.php?release=2014-335

[Rick]

Lutetia's dark side hosts hidden crater

Grooves found on Lutetia, an asteroid encountered by ESA's Rosetta spacecraft, point to the existence of a large impact crater on the unseen side of the rocky world.

Rosetta flew past Lutetia at a distance of 3168 km in July 2010, en route to its 2014 rendezvous with its target comet.

The spacecraft took images of the 100 km-wide asteroid for about two hours during the flyby, revealing numerous impact craters and hundreds of grooves all over the surface.

More: http://sci.esa.int/rosetta/54741-lutetias-dark-side-hosts-hidden-crater/

[Rick]

Rosetta's Comet Landing Site Close Up

A mosaic from the European Space Agency's Rosetta spacecraft shows "Site J," the primary landing site on comet 67P/Churyumov-Gerasimenko for the mission's Philae lander. Rosetta is the first mission to attempt a soft landing on a comet.

The mosaic comprises two images taken by Rosetta's OSIRIS narrow-angle camera on Sept. 14, 2014, from a distance of about 19 miles (30 kilometers). The image scale is 1.6 feet (0.5 meters) per pixel. The red ellipse is centered on the landing site and is approximately 1,600 feet (500 meters) in diameter.

Site J is located on the smaller of the comet's two lobes. On Nov. 12, the Rosetta spacecraft will release Philae at 01:03 a.m. PST/10:03 CET/09:03 UTC (the time the signal is received on Earth). Touchdown of Philae on Site J is expected about seven hours later, at around 8 a.m. PST/17:00 CET/16:00 UTC (Earth Received Time).

More (and the picture): http://www.jpl.nasa.gov/news/news.php?feature=4339

...oh, and another "selfie" on APOD: http://apod.nasa.gov/apod/ap141016.html

[Rick]

Rosetta's Comet Scrambling Its Jets

Images of the comet nucleus, taken by Rosetta earlier in the summer, showed that the distinct jets of dust and gas emanating from the comet were originated from the neck region, which connects the comet's two lobes. Images obtained by OSIRIS now show jets of dust along almost the entire length of the comet.

Rosetta and comet 67P are still more than 280 million miles (450 million kilometers) from the sun. Based on a rich history of ground-based observations, scientists have been expecting the comet's activity to pick up noticeably once it comes within 186 million miles (300 million kilometers).

More: http://www.jpl.nasa.gov/news/news.php?feature=4355