All posts by Tom

Hubble Looks at Saturn

Such a gem. Nice structure in .

ESA: The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on 20 June 2019 as the planet made its closest approach to Earth this year, at approximately 1.36 billion kilometres away.

Saturn hosts many recognisable features, most notably its trademark ring system, which is now tilted towards Earth. This gives us a magnificent view of its bright icy structure. Hubble resolves numerous ringlets and the fainter inner rings. Dutch astronomer Christiaan Huygens first identified the rings in 1655 and thought they were a continuous disk encircling the planet, but we now know them to be composed of orbiting particles of ice and dust. Though all of the gas giants boast rings, Saturn’s are the largest and most spectacular.

The age of Saturn’s ring system continues to be debated. And, even more perplexingly, it’s unknown what cosmic event formed the rings. There is no consensus among planetary astronomers today.

Image: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley); CC BY 4.0

Comet Borisov

An interplanetary visitor.

Credits: Canada-France-Hawaii Telescope

From NASA: A newly discovered comet has excited the astronomical community this week because it appears to have originated from outside the solar system. The object — designated C/2019 Q4 (Borisov) — was discovered on Aug. 30, 2019, by Gennady Borisov at the MARGO observatory in Nauchnij, Crimea. The official confirmation that comet C/2019 Q4 is an interstellar comet has not yet been made, but if it is interstellar, it would be only the second such object detected. The first, ‘Oumuamua, was observed and confirmed in October 2017.

The new comet, C/2019 Q4, is still inbound toward the Sun, but it will remain farther than the orbit of Mars and will approach no closer to Earth than about 190 million miles (300 million kilometers).

After the initial detections of the comet, Scout system, which is located at NASA’s Jet Propulsion Laboratory in Pasadena, California, automatically flagged the object as possibly being interstellar. Davide Farnocchia of NASA’s Center for Near-Earth Object Studies at JPL worked with astronomers and the European Space Agency’s Near-Earth Object Coordination Center in Frascati, Italy, to obtain additional observations. He then worked with the NASA-sponsored Minor Planet Center in Cambridge, Massachusetts, to estimate the comet’s precise trajectory and determine whether it originated within our solar system or came from elsewhere in the galaxy.

The comet is currently 260 million miles (420 million kilometers) from the Sun and will reach its closest point, or perihelion, on Dec. 8, 2019, at a distance of about 190 million miles (300 million kilometers).

“The comet’s current velocity is high, about 93,000 mph [150,000 kph], which is well above the typical velocities of objects orbiting the Sun at that distance,” said Farnocchia. “The high velocity indicates not only that the object likely originated from outside our solar system, but also that it will leave and head back to interstellar space.”

Currently on an inbound trajectory, comet C/2019 Q4 is heading toward the inner solar system and will enter it on Oct. 26 from above at roughly a 40-degree angle relative to the ecliptic plane. That’s the plane in which the Earth and planets orbit the Sun.

C/2019 Q4 was established as being cometary due to its fuzzy appearance, which indicates that the object has a central icy body that is producing a surrounding cloud of dust and particles as it approaches the Sun and heats up. Its location in the sky (as seen from Earth) places it near the Sun — an area of sky not usually scanned by the large ground-based asteroid surveys or NASA’s asteroid-hunting NEOWISE spacecraft.

C/2019 Q4 can be seen with professional telescopes for months to come. “The object will peak in brightness in mid-December and continue to be observable with moderate-size telescopes until April 2020,” said Farnocchia. “After that, it will only be observable with larger professional telescopes through October 2020.”  

Observations completed by Karen Meech and her team at the University of Hawaii indicate the comet nucleus is somewhere between 1.2 and 10 miles (2 and 16 kilometers) in diameter. Astronomers will continue collect observations to further characterize the comet’s physical properties (size, rotation, etc.) and also continue to better identify its trajectory.

The Minor Planet Center is hosted by the Harvard-Smithsonian Center for Astrophysics and is a sub-node of NASA’s Planetary Data System Small Bodies Node at the University of Maryland. JPL hosts the Center for Near-Earth Object Studies. All are projects of NASA’s Near-Earth Object Observations Program and elements of the agency’s Planetary Defense Coordination Office within NASA’s Science Mission Directorate.

A Space Bubble

Now here is fun topic – space bubbles. Fun and with VERY complicated physics!

ESA: Things got heated on the International Space Station this week after the Multiscale Boiling experiment, known as Rubi, was successfully switched on.  

ESA astronaut Luca Parmitano installed the shoe box-sized container studying the boiling process in the Fluid Science Laboratory of the Columbus module after its arrival on a Dragon cargo resupply mission in August. 

The experiment is now in full swing and generated its first bubble under controlled conditions.

While the bubbles form, a number of measurements are taken. The temperature sensor in the left of this image measures bubble temperature  while a high-speed camera records how the bubbles behave and an infrared camera tracks the temperature of the heated region.

Scientists will also observe and quantify the effect of external forces on the boiling process.

Rubi is equipped with an electrode to assess the effect of the electric field on the bubbles, as well as a small pump that, when activated, will get the liquid moving to evaluate flow on the boiling process.

Why space bubbles?

Scientists are investigating the boiling process in space mainly for two reasons.

Running this experiment in weightlessness has the advantage that the boiling process takes place in slow motion and the bubbles generated are much larger than on Earth allowing researchers to investigate details of the process in high resolution.

Boiling is a common process in many applications such as refrigeration or cooling of high-performance electronic devices. This research will provide valuable information for designing thermal management systems in a more efficient way, both in space as well as on Earth.

Rubi will run for five months on the International Space Station, during which time more than 600 test runs are planned.

Follow the Rubi experiment on social media for regular updates and more bubbly images and videos. 

Titan’s Lakes

The Saturn moon we know to have lakes made of liquid methane and ethane and not water. Now the formation of the lakes is being studied. Are they made from explosions? We can seriously ask these kinds of question thanks to on of the greatest planetary missions of all time — Cassini.

Image: NASA/JPL-Caltech

NASA: Using radar data from NASA’s Cassini spacecraft, recently published research presents a new scenario to explain why some methane-filled lakes on Saturn’s moon Titan are surrounded by steep rims that reach hundreds of feet high. The models suggests that explosions of warming nitrogen created basins in the moon’s crust.

Titan is the only planetary body in our solar system other than Earth known to have stable liquid on its surface. But instead of water raining down from clouds and filling lakes and seas as on Earth, on Titan it’s methane and ethane — hydrocarbons that we think of as gases but that behave as liquids in Titan’s frigid climate.

Most existing models that lay out the origin of Titan’s lakes show liquid methane dissolving the moon’s bedrock of ice and solid organic compounds, carving reservoirs that fill with the liquid. This may be the origin of a type of lake on Titan that has sharp boundaries. On Earth, bodies of water that formed similarly, by dissolving surrounding limestone, are known as karstic lakes.

The new, alternative models for some of the smaller lakes (tens of miles across) turns that theory upside down: It proposes pockets of liquid nitrogen in Titan’s crust warmed, turning into explosive gas that blew out craters, which then filled with liquid methane. The new theory explains why some of the smaller lakes near Titan’s north pole, like Winnipeg Lacus, appear in radar imaging to have very steep rims that tower above sea level — rims difficult to explain with the karstic model. 

The radar data were gathered by the Cassini Saturn Orbiter — a mission managed by NASA’s Jet Propulsion Laboratory in Pasadena, California — during its last close flyby of Titan, as the spacecraft prepared for its final plunge into Saturn’s atmosphere two years ago. An international team of scientists led by Giuseppe Mitri of Italy’s G. d’Annunzio University became convinced that the karstic model didn’t jibe with what they saw in these new images.

“The rim goes up, and the karst process works in the opposite way,” Mitri said. “We were not finding any explanation that fit with a karstic lake basin. In reality, the morphology was more consistent with an explosion crater, where the rim is formed by the ejected material from the crater interior. It’s totally a different process.”

The work, published Sept. 9 in Nature Geosciences, meshes with other Titan climate models showing the moon may be warm compared to how it was in earlier Titan “ice ages.”

Over the last half-billion or billion years on Titan, methane in its atmosphere has acted as a greenhouse gas, keeping the moon relatively warm — although still cold by Earth standards. Scientists have long believed that the moon has gone through epochs of cooling and warming, as methane is depleted by solar-driven chemistry and then resupplied.

In the colder periods, nitrogen dominated the atmosphere, raining down and cycling through the icy crust to collect in pools just below the surface, said Cassini scientist and study co-author Jonathan Lunine of Cornell University in Ithaca, New York.

“These lakes with steep edges, ramparts and raised rims would be a signpost of periods in Titan’s history when there was liquid nitrogen on the surface and in the crust,” he noted. Even localized warming would have been enough to turn the liquid nitrogen into vapor, cause it to expand quickly and blow out a crater.

“This is a completely different explanation for the steep rims around those small lakes, which has been a tremendous puzzle,” said Cassini Project Scientist Linda Spilker of JPL. “As scientists continue to mine the treasure trove of Cassini data, we’ll keep putting more and more pieces of the puzzle together. Over the next decades, we will come to understand the Saturn system better and better.”

The Cassini-Huygens mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.

JAXA’s HTV – 8 Launch

Whoa! Well that was interesting! No word yet on what the fire was all about. Here’s the replay.

No word on the recycle time for launch either.

Mission: HTV-8 Cargo-spaceship to the ISS

Agency: JAXA

Spaceport: Tanegashima Space Center, Japan

Launch Time (scheduled): 21:33 UT / 17:33 ET

Well there is certainly a problem with the scheduling software here. I can work around it for the most part – I think.

Vikram FOUND!

Well, it seems that the Vikram lander DID land more-or-less intact! Good news to be sure. It’s a bit tilted from what we have heard. More details should be coming in the days ahead and hopefully communications can be initiated.

Until then, congratulations to the ISRO and mission team!

There will be a launch later today. The launch will be the JAXA HTV-8 cargo-spaceship to the International Space Station. I plan to schedule a feed, although I should be right here; The idea is to see what is going on with scheduling.

ExoMars Coming Together

Look at that clean-room! Brings back memories; I worked in a clean-room (not that one) years ago.

ESA: The ExoMars landing platform Kazachok is seen here atop of the rear jacket of the descent module, during integration activities in Turin, Italy.  A front shield will also be placed on top.
The descent module is also now integrated with the carrier module will move on to Cannes, France for environmental testing, while the Rosalind Franklin rover undergoes environmental testing in Toulouse, France.

Tbanks to ESA and Thales Alenia Space for the nice image.

Landing Sites

Just a couple short videos today both are landing sites.

The first is the site of India’s Chandrayaan 2 Vikram lander. Communications with the lander was lost moments before landing. We do not know if the craft actually landed successfully or not. There is a pretty good chance it did and the ISRO is attempting to make contact. The contact attempts will last a reasonable amount of time.

The area looks quite interesting so let’s wish them good luck. The video from Solar System Exploration Research Virtual Institute was make with NASA’s Moon Trek, very nice bit of work too, it took a bit of time to load – your load time may vary.

The second video is a 3D rendering of the four candidate landing sites on Asteroid Bennu for the OSIRIS-REx spacecraft: