Coming this March – Reentry of Chinese Space Station

Its inevitable, what goes up must come down. On average there is one large piece of equipment that re-enters our atmosphere every week. Some are controlled and planned decommissioning of satellites after their useful life. They are purposely commanded for re-entry and burn-up in the atmosphere to avoid adding debris to our already crowded space orbits or worse, cause a collision with another satellite creating an enormous field of debris. Other objects that re-enter are left to fall on their own such as discarded rocket bodies and old satellite that ceased to operate long ago or malfunctioned and can no longer be controlled.

Tiangong-1 : First Chinese space station launched in 2011

Tiangong-1 : First Chinese space station launched in 2011

This coming March the 8,500kg (18,700lbs) Tiangong-1 Chinese space station is coming back to Earth. Launched in September 2011 and used for two manned missions, it suffered a malfunction and the Chinese have not been in control of it since 2016. The space station has been in a decaying orbit ever since, and now below the 300km altitude  where Earth’s atmosphere is causing the space station to slow down due to aerodynamic drag it will soon make its re-entry.

Delta 2 rocket fuel tank surviving re-entry near Georgetown, TX, on 22 January 1997

Delta 2 rocket fuel tank surviving re-entry near Georgetown, TX, on 22 January 1997

Now there is no need to panic. Most of Earth is ocean, and we’ll probably not see anything let alone have a piece of it land in a city. However as this is a fairly large body, there is a good chance  not all pieces will burn up and some may make it to the surface.

This isn’t the first time a space station makes a re-entry.  The American Skylab at 77 tons re-entered in 1979, and Russian Mir (120 tons) made its re-entry in 2001.
For the Mir re-entry, Taco Bell even got it onto the re-entry buzz by anchoring a large

Taco Bell target for Mir re-entry (2001)
Taco Bell target for Mir re-entry (2001)

target off the Australian coast along the planned re-entry track, and should Mir crash into it there would be free tacos for all Americans. The fast food chain even took out an insurance policy just in case it would happen.

In early January 2018, Tiangong-1 is orbiting at an altitude of around 270-290km (to put that into perspective, ISS is at a 400km orbit) and in a 45 deg orbit, hence the re-entry will be within those latitudes.  The green area in the map below is where Tiangong-1 could make a re-entry, and also marks where the re-entry could be observed.

Tiangong-1 ground coverage - http://www.aerospace.org

Tiangong-1 ground coverage – http://www.aerospace.org

It’s still too early to determine the time and location of potentially crash site, as Earth’s atmosphere is influenced by space weather and swells based on our Sun’s moods, which alters the drag force on the space station.  However various space centers and organizations will continue to track the space station the coming weeks to improve the prediction.

You can follow everything at Aerospace.org for up to date information and predictions.

What could the re-entry look like?  Below is a video shot by NASA of the Japanese Hayabusa spacecraft during a controlled re-entry on June 13, 2010

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Star Trails, Plane, Meteor and Cosmic Ray

Simply setting up a camera to take a series of images of the night sky can pick up a lot more than a few stars.

trails_secondaries_smallIf you have a wide-angle lens, and live near a large city there is a good chance that some aircraft will fly into the field of view.  The linear streak and alternating lights are a dead give-away of a plane having crossed the camera’s field of view.  If you don’t have the alternating lights, it’s mostlikely an orbiting satellite reflecting sunlight.

Meteors are also somewhat of a common occurrence.  These are easily recognized by their characteristic increasing than decreasing brightness as they burn up in the upper atmosphere. The meteor in the image above is from the Geminid shower.

The last artifact comes for outside our solar system, it is cosmic rays.  The CCD or CMOS sensor of your camera works by performing an electric read-out of photons captured by the lens.  Cosmic rays are high-energy sub-atomic particles that have traveled through space and managed to make it through the atmosphere down to us.  The one in the photo above just happens to hit my camera sensor.  As the near light-speed sub-atomic particle smashes into atoms on the sensor it looses energy, freeing up electrons which register as “light” by the CCD.  Most of the time the cosmic ray will hit the sensor straight on,  but sometimes it impacts at a shallow angle and causes a series of pixels to “light” up, as in the photo above.

Take time to examine your photos, you never know what surprises you may find.

Does Earth Influence the Sun?

I recently came across an article in the french Science & vie magazine, where a reader asked if Earth influences the Sun. I found it rather interesting, and while I had my doubts I still wanted to know more about it.

sun-earth

The reader wasn’t the first to wonder if there was any interaction, various models and observations have been put forward since the late 1800s. We often read about two bodies interacting in space. The first exoplanet was discovered due to its gravitational influence on its star causing it to wobble. This type of gravitational influence works when two bodies have a mass within one or two orders of magnitude of each other.  But in the case of our Sun, it is 99.86% of the solar system’s mass, and most of the remaining is taken up by Jupiter and Saturn.  Therefore from a gravitational perspective Earth has no effect on the Sun.

But could the 11 year period in solar activity, characterized by the rise and fall of number of observed sun spots be caused by the planets? The exact source of that periodicity has yet to be clarified.  Well a team of researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) put out a paper in 2016 after demonstrating that every 11.07 years the planets Venus, Earth and Jupiter are aligned.  Coincidence?

They explained that while the effects are rather small, the repeated nudging could be enough to tip the Sun’s magnetic field instabilities one way or the other causing this 11 year solar cycle that we observe, much like an object entering into resonance.  In this case it’s the Sun’s magnetic field acting like a dynamo that would resonate due to the planet’s alignment every 11 years.

However many are skeptical about any real effect pointing that the source of the Sun’s magnetism comes from deep within, while the planet’s effect, if ever, would be limited to the Sun’s surface. But the crushing blow is when you look at fact that the solar cycle varies between 7 and 14 years, the number 11 just happens to be the average over the last 24 observed cycles.  Unfortunately the three planet’s alignment don’t vary by that amount.

In the end, the Sun is still king and does what it wants in this solar system, regardless what the planets say or do.

EXOPLANET SERIES – TRAPPIST-1

On Wednesday NASA made headlines by announcing that researchers had detected seven exoplanets orbiting a dim dwarf star.  These exoplanets are determined, based on measurements, to be approximately Earth-sized solid planets and three happen to fall in the “Goldilocks Zone” where water could exist in liquid form; not too hot, not too cold.  Lots of people started speculating that in a few years we’ll find out if one of those planets harbors life.  However that is just plain crazy-talk.  The importance of this discover is that complex exoplanet systems do exist; the Solar System is not an exception, and that life is also not an exception.

The TRAPPIST-1 system

The TRAPPIST-1 system contains a total of seven planets, all around the size of Earth. Three of them — TRAPPIST-1e, f and g — dwell in their star’s so-called “habitable zone.” [NASA/JPL]

0.60m Ritchey-Chrétien Reflector [TRAnsiting Planets and PlanetesImals Small Telescope–South / ESO]

0.60m Ritchey-Chrétien Reflector [TRAnsiting Planets and PlanetesImals Small Telescope–South / ESO]

The TRAnsiting Planets and PlanetesImals Small Telescope–South made the discovery back in May 2016 of three exoplanets around the small star.  But it was with the help of larger telescopes and the space-based Spitzer telescope that the count increased to seven and their orbits could be confirmed.  What I find interesting is the initial discover was done by a relatively “small” 0.60m telescope.  OK not your typical backyard astronomy gear, but scale that down by 1/3 and you have equivalent optics for about $3000.  Add a mount and CCD and for $10,000 you could probably have your very own exoplanet hunter!

Back to the crazy-talk of finding life in this exoplanet system… Anyone who has studied the history and formation of the Solar System knows that there have been a series of unlikely events that have led to where we are today.  Starting with the Sun, probably a 3rd generation star, where heavy elements like Calcium and Iron necessary for life as we know it were produced by previous stars and supernovas that used to exist in this spot of the galaxy we now occupy.  All elements beyond Hydrogen are produced by stars, either through fusion or when they dramatically explode as supernovas.  The atoms making up the air, the trees, the oceans, ourselves were not created in our Solar System during its formation.  The Sun is currently only generating Helium and Lithium out of Hydrogen through the wonders of fusion.  All the heavier atoms within us were created by previous stars that no longer exist.  Hence for solid Earth-like exoplanets to exists there needs to have been one to two previous generation of stars in the region.

An alien race observing our Solar System would surely first spot Jupiter.  One could almost say that it characterizes our home in this part of the galaxy.  With its strong gravity this gas giant plays the vital role of neighborhood vacuum cleaner.  It is either mopping up or launching away asteroids and comets that would otherwise impact Earth, bringing relative calm to the inner Solar System.  If Earth was constantly bombarded by solar objects, there is no way that life could suitably evolve from slimy unicellular organisms.  It took 3 billion years for multi-cellular organisms to show up once life appeared on Earth.  If cataclysmic comet and asteroid impacts are a frequent occurrences, then there is little chance that complex organisms would come to be.

Looking at another element, TRAPPIST-1 is described as an ultra-cool dwarf star just shy of 40 light years from Earth in the constellation Aquarius.  If we forget that it’s a fraction of our Sun’s size and brightness (hence heat generation), it is relatively young at 1 billion years old.  So while there may be three planets that could be habitable, life may not have even begun yet.  Our own Sun is 4.3 billion years old, and the animals we see around us have only been around for the last 14-16 million years.  So what could be in a 1 billion year old planetary system? Assuming all the ingredients are there for life to exist, you probably only have bacterial soup.

Now, my article was getting long, and I wanted to cover many more subjects, too many for a single article.  Hence I’ve decided to break them out into the EXOPLANET SERIES and will publish them over time.

 

2017 Event : Total Solar Eclipse for North America

Every given year there are between two and five solar eclipses, this upcoming one for August 21st will be special.  The last total solar eclipse for North America goes back to 2008.  As Earth is largely covered by water, many of the eclipses are over the ocean where the number of viewers are limited.  But this one will pass over millions of people, all with access to equipment and social media to share their experience.  Hence this one has lots of people planning and getting ready.  The eclipse is most impressive when you’re located in the path of totality; where the Moon completely blocks out the Sun.  Hence if you are able to travel to such a location along its path, it will be worth it.  I also suggest finding a local astronomy group or association as they will most-likely have telescopes and other special observing gear out for everyone to use.

August 2017 Total Solar Eclipse.

The total solar eclipse will only be viewed in the narrow path crossing the middle of the USA. North and south of that will get a partial eclipse. The green vertical lines indicate the time of maximum eclipse. Courtesy Michael Zeiler, GreatAmericanEclipse.com.

Observing the solar eclipse requires protective eye-wear and solar filters for any observing or photographic equipment.  For my telescope it’s a film solar filter, now branded SolarLite by Thousand Oaks Optical.  These can be purchased already mounted in an aluminium cell or in sheets for your own custom application.

Thousand Oaks Optical R-G Solar Filter

Thousand Oaks Optical R-G Solar Filter

The American Astronomical Society has created a web site just for the event with plenty of information on safe observation and suppliers of necessary optical filters.

Stay tuned…

JunoCam – Revealing Jupiter from New Angles

JunoCam onboard the Juno spacecraft is providing us with some great pictures of the Jupiter cloud top, but from the rarely seen polar angle.  Pretty much all spacecrafts that have visited Jupiter did so with a fly by along the equatorial plane, which is also the same plane we observe Jupiter here on Earth.  However with the Juno spacecraft, we now have a chance to enter into a polar orbit and take pictures of the polar regions.

Part of the reason behind JunoCam is to get the amateur astronomer community participating in selecting what parts of Jupiter the camera should be snapping pictures, and of processing the raw images.  The image below was captured by JunoCam during Juno’s 3rd swing around Jupiter at a distance of about 37,000km.  The south polar region is on the left.

Jupiter - December 11, 2016 JunoCam - Juno Spacecraft

NASA, JPL-Caltech, SwRI, MSSS; Processing: Damian Peach

The above was the PeriJove3 encounter (3rd pass), and voting on the next PeriJove4 will take place between January 19th and 23rd 2017.  This is where the community can propose and vote for Points of Interest to photograph with JunoCam during the rather quick (2 hours) close pass with Juno.  You can even submit images of Jupiter taken with your equipment to help plan the Points of Interest.

Ref: JunoMission

NASA Juno Mission Trailer: JOI

Video

Space-thriller themed mission trailer

Secrets lie deep within Jupiter, shrouded in the solar system’s strongest magnetic field and most lethal radiation belts. On July 4, 2016, NASA’s Juno spacecraft will plunge into uncharted territory, entering orbit around the gas giant and passing closer than any spacecraft before. Juno will see Jupiter for what it really is, but first it must pass the trial of orbit insertion. For more information: http://www.nasa.gov/juno and http://missionjuno.swri.edu