Wind Delays Aeolus Launch

In kind of an ironic twist, the Aeolus mission which will study the winds on Earth, the mission start has been delayed by – winds.

New launch date: 22 August 2018

Launch time: 18:20 French Guiana / 21:20 UTC

The image shows Aeolus in the tower prior to being mounted atop the rocket that will launch into orbit.  Image courtesy ESA/CNES /Arianespace.

From ESA:   Wind conditions in the atmosphere along the launcher’s trajectory are among the flight safety elements taken into account for every Arianespace mission. With this one-day postponement, the liftoff of Flight VV12 is now set for August 22 at exactly 6:20:09 p.m., local time in French Guiana.

The mission with Aeolus will be performed with a Vega launcher – provided by prime contractor Avio of Italy – marking the 12th flight of Arianespace’s light-lift vehicle since entering service at the Spaceport in February 2012.

Both the Vega launcher and its Aeolus payload for Flight VV12 are in stabilized configurations and under fully secure conditions at the Spaceport’s Vega Launch Complex.

Aeolus is a European Space Agency-organized mission to provide much-needed data in improving the quality of weather forecasts and contributing to long-term climate research. Built by Airbus Defence and Space, the satellite carries a laser Doppler wind LIDAR (Light Detection and Ranging) system called Aladin that will probe the lowermost 30 km. of the atmosphere in measuring winds around the Earth.

The Interior of Ceres

One of the interesting things about Ceres is it is actually less dense (2161 Kg/cubic meter) than the Jupiter moon Europa (3013 Kg/cubic meter). It does begin to make more sense after learning there may be some sort of brine making up the interior.

Knowing the density we should be able to figure out how fast something falls.  Let’s try (hopefully I get the maths right):

We are clumsy and fall so our initial velocity is zero.  So the formula would be:

distance = 0.5*g*time^2 (that is time squared) and velocity = g*time.

We have a 30 meter platform.  if we fell off here on Earth gravity (9.8 m/sec2) we would hit the ground in about 1.4 seconds at a velocity of 14 m/sec – a very hard hit indeed.

On the Moon it would be (1.6 m/sec2) about 3.5 seconds to fall and we would hit at a velocity of 5.7 m/sec – a hard hit also, not as bad as on Earth but still hard.

And on Ceres (0.3 m/sec), the time to hit the ground would be by comparison a leisurely 8.2 seconds, ha we could take in the sights, our velocity would be  a tiny bit less than 2.5 m/s.  About like jogging straight into a wall and provided we did not puncture our space suit we would probably not suffer too much in the way of serious injury.

Anyway, sorry I couldn’t help myself, back to the image.

NASA’s caption: This artist’s concept summarizes our understanding of how the inside of Ceres could be structured, based on the data returned by the NASA’s Dawn mission.

Using information about Ceres’ gravity and topography, scientists found that Ceres is “differentiated,” which means that it has compositionally distinct layers at different depths. The most internal layer, the “mantle” is dominated by hydrated rocks, like clays. The external layer, the 24.85-mile (40-kilometer) thick crust, is a mixture of ice, salts, and hydrated minerals. Between the two is a layer that may contain a little bit of liquid rich in salts, called brine. It extends down at least 62 miles (100 kilometers). The Dawn observations cannot “see” below about 62 miles (100 kilometers) in depth. Hence, it is not possible to tell if Ceres’ deep interior contains more liquid or a core of dense material rich in metal.


SLS RS-25 Engine Test

Note: The original version of this post was supposed to publish on the 16th. I am still trying to figure out what went wrong. Here’s a second try.

What an engine!

NASA (Valerie Buckingham): Stennis Space Center showcased what it does best for new NASA Administrator Jim Bridenstine on Aug. 14, hosting the agency leader for the first in another series of RS-25 rocket engine hot fire tests in support of NASA’s Space Launch System (SLS) Program.

Operators conducted a successful test of RS-25 developmental engine No. 0525 – complete with a new flight controller unit – on the A-1 Test Stand as Bridenstine and other agency officials watched. The visit was Bridenstine’s first to the south Mississippi center since he was confirmed as administrator in April.

“I have witnessed rocket launches before, but this was a new and unique experience,” Bridenstine said following the test. “It was like watching a launch, but it never leaves the ground, and you can feel the power of the engine within your body. And what the power of this RS-25 engine represents is America’s ability to fly deeper into space than we ever did before. This was a great test.”

“It was an honor to host Administrator Bridenstine and to provide him an opportunity to see the Stennis test team work,” Stennis Director Rick Gilbrech said. “It also is an honor to be part of the effort under way to help move this nation to the Moon again, then on to Mars.”

The Aug. 14 hot fire was the first RS-25 test at Stennis since February, when operators powered the engine to its highest operating level ever. It also was the first test of developmental engine No. 0525 since August 2015. It marked the first in a series of nine scheduled tests on engine No. 0525 through the rest of the year and into 2019. Each will feature an RS-25 flight controller for use on an actual SLS mission, as well as testing engine components made with innovative manufacturing designed to reduce the cost of future engines. All test objectives were met during the hot fire.

NASA is building the SLS rocket as the largest, most powerful space vehicle in history to return humans to deep space missions. The SLS rocket will launch crews of up to four astronauts aboard the Orion spacecraft to explore various deep-space destinations, including the Moon and Mars.

Each SLS rocket will be powered at launch by four RS-25 engines firing simultaneously to provide a combined 2 million pounds of thrust and working in conjunction with a pair of solid rocket boosters to provide more than 8 million pounds of thrust. RS-25 engines are being built by Aerojet Rocketdyne for the SLS flights.

The initial RS-25 engines are former space shuttle main engines. For initial SLS flights, the engines will be operated at 109 percent of rated power. For subsequent SLS flights, designed to carry larger, heavier cargos and the crew vehicle to deep space, the engines have been modified to operate at 111 percent of rated power. To date, Stennis has conducted 22 tests running with engines operating just over 10,000 cumulative seconds for SLS.

A key component of latest modification is the controller, which operates as the “brain” of the engine to help it communicate with the rocket and to provide precision control of engine operation and internal health diagnostics.

Stennis tested the first RS-25 flight controller in March 2017. For the testing, flight controller units are installed on a developmental engine and fired just as during an actual launch. Once tested and certified, the controllers are removed for installation on an RS-25 flight engine.

To get the most out of each test, NASA is not only testing the flight controllers, but also is testing parts of the engine that can be made using new manufacturing techniques. When new engines are produced, components can be made with these advanced processes, and the engine production cost can be reduced by more than 30 percent. This test featured a main combustion chamber fabricated using a bonding technique called hot isostatic pressing (HIP), which saves considerable time and money over more traditional methods. The HIP process uses high pressure and heat to create bonds that can withstand extreme stress. It already has been used on main combustion chambers in two other Aerojet Rocketdyne engines.

The Aug. 14 hot fire also represented the fifth test of a 3D-printed pogo accumulator assembly, a critical component that dampens potential engine propellant pressure oscillations that can cause a rocket to become unstable in flight. Testing of the 3D-printed component also is part of the ongoing effort to use advanced manufacturing to reduce engine construction costs. NASA and Aerojet Rocketdyne plan to test a number of 3D-printed components for the RS-25 engine.

In addition to testing individual RS-25 engines and components, Stennis is preparing to test the core stage for the first SLS flight – Exploration Mission-1 – which will showcase the new rocket and send an uncrewed Orion spacecraft into space beyond the Moon. For that testing, the flight core stage will be installed on the B-2 Test Stand at Stennis, and all four RS-25 engines will be fired simultaneously.

The first flight will be followed by Exploration Mission-2, which will carry humans aboard the Orion spacecraft, returning astronauts to deep space for the first time in more than 40 years. This mission will also be powered by Stennis-tested engines.

RS-25 tests at Stennis are conducted by a team of NASA, Aerojet Rocketdyne and Syncom Space Services engineers and operators. Aerojet Rocketdyne is the RS-25 prime contractor. Syncom Space Services is the prime contractor for Stennis facilities and operations.

Magnetic Field Lines

I would like to see more of this. Actually I’d also like to see this done from a more distant perspective. Good work though.

The dark areas by the way are a source of solar winds which are probably not not cause earthquakes here on Earth; we start hearing that because the “other” cause (which also cannot be correlated) are sunspots and solar flares. I guess when you don’t get one you can fall back on the other.

One other thing we can see is the absence of high latitude sunspots which would be the hallmark of a new solar cycle. So are we in a “Grand Solar Minimum? Maybe, come back in ten years or so and if we are still stuck at solar minimum levels we could possibly say yes. It’s WAY too early to make such claims at this point. So when you hear that on the internet be sure to take it with a box of salt.

NASA’s caption: NASA’s Solar Dynamics Observatory (SDO) scientists used their computer models to generate a view of the Sun’s magnetic field on August 10, 2018. The bright active region right at the central area of the Sun clearly shows a concentration of field lines, as well as the small active region at the Sun’s right edge, but to a lesser extent. Magnetism drives the dynamic activity near the Sun’s surface.

SDO is managed by NASA’s Goddard Space Flight Center, Greenbelt, Maryland, for NASA’s Science Mission Directorate, Washington. Its Atmosphere Imaging Assembly was built by the Lockheed Martin Solar Astrophysics Laboratory (LMSAL), Palo Alto, California.

Image Credit: NASA/GSFC/Solar Dynamics Observatory

Proba’s Solar Eclipses

ESA: Thanks to a quirk of our cosmos, the Moon’s average distance from Earth is just right for it to appear as the same size in the sky as the significantly larger Sun. Once in a while the Moon slides directly between Earth and the Sun such that it appears to cover our star completely, temporarily blocking out its light and creating a total solar eclipse for those along the narrow path cast by the Moon’s shadow.

But sometimes the alignment is such that the Moon only partially covers the Sun’s disc. Such a partial eclipse occurred on Saturday for observers located primarily in northern and eastern Europe, northern parts of North America, and some northern locations in Asia.

ESA’s Sun-watching Proba-2 satellite orbits Earth about 14.5 times per day and with its constant change in viewing angle, it dipped in and out of the Moon’s shadow twice during Saturday’s eclipse.

Selected views of the two partial eclipses are seen side-by-side here – the first (left) was captured at 08:40:12 GMT and the second (right) at 10:32:17 GMT on 11 August.

The images were taken by the satellite’s SWAP camera, which works at extreme ultraviolet wavelengths to capture the Sun’s hot turbulent atmosphere – the corona – at temperatures of about a million degrees, which can be seen in the background.

Watch the full image sequence here.

Image: ESA/Royal Observatory of Belgium

From The Travels of Cassini

Here’s sort of a throwback, one of Cassini’s great images newly processed.  The release title is “Translucent Arcs” and that is very descriptive. To me the image show the ring structure in terms of thickness density. Combined with the Sun-Saturn-Cassini angular configuration the rings seem to provide almost a “screen-door” effect to the scene.

This view is much different than what was published in 1622 by Fortunio Liceti in De Novis Astris et Cometis and much different than the sight from a backyard telescope.

Saturn is nothing short of breathtaking, if you’ve never seen it put it on your “bucket list” and look for suitable viewing opportunities — you might be surprised, local colleges and universities sometimes have public viewing and don’t overlook local astronomy clubs.

Here’s the caption from NASA:  Saturn’s rings are perhaps the most recognized feature of any world in our solar system. Cassini spent more than a decade examining them more closely than any spacecraft before it.

The rings are made mostly of particles of water ice that range in size from smaller than a grain of sand to as large as mountains. The ring system extends up to 175,000 miles (282,000 kilometers) from the planet, but for all their immense width, the rings are razor-thin, about 30 feet (10 meters) thick in most places.

From the right angle you can see straight through the rings, as in this natural-color view that looks from south to north. Cassini obtained the images that comprise this mosaic on April 25, 2007, at a distance of approximately 450,000 miles (725,000 kilometers) from Saturn.

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

Image: NASA/JPL-Caltech/Space Science Institute

The Origin of the Perseids

Ever wonder where the Perseids come from? Wonder no more because this is Comet Swift-Tuttle and it is the origin of the Perseids showers.

I have been stymied in my viewing thanks to persistent clouds. In the few breaks I have managed to see a few meteors. Yesterday morning mostly, trying to watch the meteors and the launch of the Parker Space Probe (from the outside and through a window) at the same time.

Here’s ESA’s caption for the image above (E.E. Barnard/Internet Archive ):Comet Swift–Tuttle, formally 109P/Swift–Tuttle, is an enormous, icy comet on a 133 year orbit around the Sun, and the reason for the spectacular annual Perseids meteor showers on Earth.

This image shows the comet photographed on 4 April 1892 (top) and 6 April 1892 (bottom) by Professor EE Barnard, taken from Plate III in A Popular History of Astronomy in the nineteenth century by Agnes M Clerke (third edition), courtesy of Internet Archive.

Once a year, Earth passes through a section of Swift–Tuttle’s cometary tail — a cloud of particles ejected from the comet, most of which have been in this formation for a thousand years. As these tiny particles enter Earth’s atmosphere at extremely fast speeds, they burn up, resulting in the wonderful show that is a meteor shower.

Every year from the middle of July to late August, observers are treated to the spectacle of glowing cosmic debris, streaming across the night’s skies. This year the shower will peak from the evening of Sunday 12 August to the early hours of Monday 13 August. The Moon will be a new crescent moon, fortunately setting before the show really gets underway and so leaving the skies dark for what is set to be the best shower of 2018.

Discovered in 1862, the ‘near-Earth comet’ Swift–Tuttle has a nucleus 26 km in diameter — that’s two-and-a-half times the size of the asteroid that wiped out the dinosaurs, and it is travelling four times as fast.

As the largest Solar System object (bar the Moon) to repeatedly pass close to Earth, comet Swift-Tuttle’s movements have been meticulously studied by scientists around the globe. It’s most recent ‘perihelion’ — the point in its orbit in which it comes closest to the Sun — was in 1992, and the next won’t be until 12 July 2126.

Fortunately all of comet Swift–Tuttle’s orbits for the next 2000 years have been intricately calculated, when Earth is 100% safe – passing for example 22.9 million km from Earth in 2126 and 22 million km in 2261.

A close encounter is expected around 15 September 4479, when Swift-Tuttle is expected to pass within 1.6 million km of Earth — more than 90 times closer than the Sun, or, only about four times the distance of the Moon.

So, for the foreseeable future we will continue to enjoy the beautiful show put on every year by the remnants of this Sun-grazer’s historic journeys to the centre of our Solar System. These stunning events also serve as a reminder that our planet has been visited before by huge cosmic space-rocks, and has the potential to be once again.