Crescent of Enceladus

Cassini may be gone, but the legacy lives on.

NASA – The brightly lit limb of a crescent Enceladus looks ethereal against the blackness of space. The rest of the moon, lit by light reflected from Saturn, presents a ghostly appearance.

Enceladus (313 miles or 504 kilometers across) is back-lit in this image, as is apparent by the thin crescent. However, the Sun-Enceladus-spacecraft (or phase) angle, at 141 degrees, is too low to make the moon’s famous plumes easily visible.

This view looks toward the Saturn-facing hemisphere of Enceladus. North on Enceladus is up. The above image is a composite of images taken with the Cassini spacecraft narrow-angle camera on March 29, 2017 using filters that allow infrared, green, and ultraviolet light. The image filter centered on 930 nm (IR) was is red in this image, the image filter centered on the green is green, and the image filter centered on 338 nm (UV) is blue.

The view was obtained at a distance of approximately 110,000 miles (180,000 kilometers) from Enceladus. Image scale is 0.6 miles (1 kilometer) per pixel.

The Cassini spacecraft ended its mission on Sept. 15, 2017.

Credit: NASA/JPL-Caltech/Space Science Institute

NGC 6753 From Hubble

Galaxy NGC 6753, imaged here by the NASA/ESA Hubble Space Telescope, is a whirl of color — the bursts of blue throughout the spiral arms are regions filled with young stars glowing brightly in ultraviolet light, while redder areas are filled with older stars emitting in the cooler near-infrared.

But there is more in this galaxy than meets the Hubble eye. At 150 million light-years from Earth, astronomers highlighted NGC 6753 as one of only two known spiral galaxies that were both massive enough and close enough to permit detailed observations of their coronas. Galactic coronas are huge, invisible regions of hot gas that surround a galaxy’s visible bulk, forming a spheroidal shape. Coronas are so hot that they can be detected by their X-ray emission, far beyond the optical radius of the galaxy. Because they are so wispy, these coronas are extremely difficult to detect.

Galactic coronas are an example of telltale signs astronomers seek to help them determine how galaxies form. Despite the advances made in past decades, the process of galaxy formation remains an open question in astronomy. Various theories have been suggested, but since galaxies come in all shapes and sizes — including elliptical, spiral, and irregular — no single theory has so far been able to satisfactorily explain the origins of all the galaxies we see throughout the Universe.

For more information about Hubble, visit: www.nasa.gov/hubble

Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt
Text credit: European Space Agency

NROL-42 Launch – Replay

Early this morning the US launched a satellite, NROL-42, from Vandenberg Air Force Base aboard an Atlas V rocket.

The satellite and what it does is classified so is not public. What was public was the launch time. I’m not one for looking at the comments in most videos, but from the ones I did see, a few people were wondering what was gong on.

Video

Arecibo Observatory Damage

The Arecibo Observatory was damaged, along with the rest of Puerto Rico, by Hurricane Maria.

The National Geographic is reporting everyone is safe and that’s excellent! Initial reports indicated significant damage including:

“Because of the storm, a 96-foot line feed antenna—which helps focus, receive, and transmit radio waves—broke in half and fell about 500 feet into the huge dish below, puncturing it in several places, says Pennsylvania State University’s Jim Breakall, who talked with Vazquez.

A fixture of the observatory since 1966, that line feed weighs about ten thousand pounds and is easily visible in images of the telescope as the pointy thing hanging off the platform. It was once used to detect mountains on the surface of Venus, and it is still crucial for studies of the part of Earth’s atmosphere called the ionosphere, says former observatory director Frank Drake, who is also my dad.”

Read the National Geographic release by Nadia Drake, it’s very good and we appreciate the news.

Video: News – Around The World

September Equinox is Here!

Today is the September Equinox, that point where the the plane of Earths center of the Sun. Spring in the southern hemisphere and Autumn in the north.

Equinox time is 20:02 UT / 16:02 ET.

I’m not a big fan of the September Equinox. Shorter and colder days ahead.

Slingshot Day is Here

And so is the September Equinox!

Today OSIRIS-REx will fly to around 11,000 miles / 17,702 km to the Earth at 16:50 UT / 12:50 ET and will get a gravity assist to slingshot it to the near-Earth asteroid Bennu.

Hubble Sees a Binary Asteroid

It’s an asteroid pair and also classified as a main belt comet. Very nice work!

NASA — Hubble was used to image the asteroid, designated 300163 (2006 VW139), in September 2016 just before the asteroid made its closest approach to the Sun. Hubble’s crisp images revealed that it was actually not one, but two asteroids of almost the same mass and size, orbiting each other at a distance of 60 miles.

Asteroid 300163 (2006 VW139) was discovered by Spacewatch in November 2006 and then the possible cometary activity was seen in November 2011 by Pan-STARRS. Both Spacewatch and Pan-STARRS are asteroid survey projects of NASA’s Near Earth Object Observations Program. After the Pan-STARRS observations it was also given a comet designation of 288P. This makes the object the first known binary asteroid that is also classified as a main-belt comet.

The more recent Hubble observations revealed ongoing activity in the binary system. “We detected strong indications for the sublimation of water ice due to the increased solar heating — similar to how the tail of a comet is created,” explained team leader Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany.

The combined features of the binary asteroid — wide separation, near-equal component size, high eccentricity orbit, and comet-like activity — also make it unique among the few known binary asteroids that have a wide separation. Understanding its origin and evolution may provide new insights into the early days of the solar system. Main-belt comets may help to answer how water came to a bone-dry Earth billions of years ago.

The team estimates that 2006 VW139/288P has existed as a binary system only for about 5,000 years. The most probable formation scenario is a breakup due to fast rotation. After that, the two fragments may have been moved further apart by the effects of ice sublimation, which would give a tiny push to an asteroid in one direction as water molecules are ejected in the other direction.

The fact that 2006 VW139/288P is so different from all other known binary asteroids raises some questions about how common such systems are in the asteroid belt. “We need more theoretical and observational work, as well as more objects similar to this object, to find an answer to this question,” concluded Agarwal.

The research is presented in a paper, to be published in the journal Nature this week.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

For additional images, visit: http://hubblesite.org/news_release/news/2017-32

Credits: NASA, ESA, and J. DePasquale and Z. Levay (STScI)

 

Hurricane Maria Hits Puerto Rico

Puerto Rico has been run-over by a very powerful hurricane. Hurricane Maria hit the island head on with winds at 134 knots.

Reports are saying power is out everywhere and there is widespread damage.   This was a devastating hit.   Hopefully everyone on the island is safe.

No word yet on how the Arecibo Observatory made out.  The observatory made it through Irma, but that was a glancing blow.

Heat Shield Testing

I am trying to figure out how they keep the thermocouple wires to keep from burning off.

NASA – NASA heat shield material that could one day be used on an inflatable aeroshell during atmospheric entry on Mars recently underwent testing at Boeing’s Large Core Arc Tunnel in St. Louis, Missouri.

The inflatable aeroshell, using high temperature advanced flexible material systems, will enable atmospheric entry to planetary bodies and the landing of heavy payloads. The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) project is focused on development of the inflatable aeroshell technology and manufacturing capability at large scale, to support an orbital atmospheric entry flight experiment at Earth and Mars. HIAD overcomes size and weight limitations of current rigid systems by utilizing inflatable soft-goods materials that can be packed into a small volume and deployed to form a large aeroshell before atmospheric entry.

Critical to the development of the technology is development of flexible material systems whose performance must be verified through arc jet testing. During early August testing, small cutouts of the Flexible Thermal Protection System (F-TPS), about 2.5 inches (6.4 cm) in diameter and anywhere from a half-inch (1.3 cm) to 1 inch (2.5 cm) thick, were placed in a supersonic wind tunnel and blasted with jets of superheated plasma gas. The plasma gas hit the cutouts at speeds of Mach 4 or more, and heated the surfaces to temperatures up to approximately 2,700 F. Thermocouples embedded in the samples measured the material’s response to the superheated conditions.

Researchers calibrated tunnel pressure and temperature to be similar to the range of conditions HIADs would face during atmospheric entry on Earth and Mars. The data from these tests will be used to validate mathematical models used for design.

The test team included researchers Steven Tobin, Matt Wells and Andrew Brune of NASA’s Langley Research Center in Hampton, Virginia; and Grant Rossman, a Ph.D. candidate at the Georgia Institute of Technology in Atlanta.

HIAD technology is being developed by researchers at Langley through NASA’s Game Changing Development program, which is part of the agency’s Space Technology Mission Directorate. The program advances space technologies that may lead to entirely new approaches to space missions.

Image: Boeing / NASA

Last Light for Cassini

NASA —  This monochrome view is the last image taken by the imaging cameras on NASA’s Cassini spacecraft. It looks toward the planet’s night side, lit by reflected light from the rings, and shows the location at which the spacecraft would enter the planet’s atmosphere hours later.

A natural color view, created using images taken with red, green and blue spectral filters, is also provided (Figure 1). The imaging cameras obtained this view at approximately the same time that Cassini’s visual and infrared mapping spectrometer made its own observations of the impact area in the thermal infrared.

This location — the site of Cassini’s atmospheric entry — was at this time on the night side of the planet, but would rotate into daylight by the time Cassini made its final dive into Saturn’s upper atmosphere, ending its remarkable 13-year exploration of Saturn.

The view was acquired on Sept. 14, 2017 at 19:59 UTC (spacecraft event time). The view was taken in visible light using the Cassini spacecraft wide-angle camera at a distance of 394,000 miles (634,000 kilometers) from Saturn. Image scale is about 11 miles (17 kilometers).