David Dickinson, Author at Universe Today

April 30, 2013December 23, 2015 by David Dickinson

Watch for the Eta Aquarid Meteor Shower this Weekend

The radiant of the Eta Aquarids rising. Looking to the south east from latitude 30 degrees north about 3 hours before local sunrise on May 5th. (Created by the author in Stellarium).

An often ignored meteor shower may offer fine prospects for viewing this weekend.

The Eta Aquarid meteors provide a dependable display in early May. With a radiant very near a Y-shaped asterism in northern Aquarius, the Eta Aquarids are one of the very few major showers that provide a decent annual show for southern hemisphere residents.

This year, the peak of the Eta Aquarids as per the International Meteor Organization (IMO) comes on May 6^th at 1:00 UT, or 9:00 PM EDT on May 5th. This favors European longitudes eastward on the morning of Monday, May 6^th. The Eta Aquarid radiant rises just a few hours before dawn, providing optimal viewing in the same time frame.

Keep in mind, the shower is active from April 19^th to May 28^th. Predicting the arrival of the peak of a meteor shower can be an inexact science. North American observers may still see an early arrival of the Eta Aquarids on May 5^th or even the morning of the 4^th.

Could “the 4^th be with us” at least in terms of meteor shower activity?

The Eta Aquarids are one of two annual meteor showers associated with that most famous of comets: 1P/Halley. The other shower associated with Halley’s Comet is the October Orionids. This makes it one of the very few periodic comets associated with two established annual meteor showers.

Like the Orionids, the Eta Aquarid meteors have one of the highest atmospheric velocities of any shower, at 66 kilometres per second. Expect short, swift meteors radiating from low in the southeast (or northeast if you’re based south of the equator) a few hours before local dawn.

This year’s ZHR is expected to reach 55. This year also offers outstanding prospects, because the Moon is only a 17% illuminated waning crescent just 4 days from New at the shower’s peak. There’s some thought in the meteor observing community that this shower experiences a cyclical peak every 12 years.

If this is indeed the case, we could be headed towards a mild lull in this shower around the 2014 to 2016 time frame. Performances from the Eta Aquarids over the past few years as per data from the IMO seem to bear this out, with a peak around 2009;

2012=ZHR 69

2011=ZHR 63

2010=No data

2009=ZHR 90

2008=65

Still, 55 per hour is a respectable shower. Keep in mind, the ZHR stands for the “Zenithal Hourly Rate” and is an ideal number. This is the number of meteors an observer could expect to see under dark skies with no light pollution with the radiant directly overhead. Also, remember that no single observer can monitor the entire sky at once!

This is also one of the last big annual showers of the season until the Perseids in mid-August. The Gamma Delphinids (June 11^th) and the June Bootids (Jun 27^th and the June Lyrids (June 15^th) are the only minor showers in June. July also sees another minor shower radiating from the constellation Aquarius, the Delta Aquarids which peak on July 30^th. The daytime Arietids in June would put on a fine annual showing if they didn’t occur in… you guessed it… the daytime.

This weekend’s Eta Aquarids will put on a better display for the southern hemisphere, one of the very few showers for which this is true.

It’s a poorly understood mystery. Why does the northern celestial hemisphere seem to contain a majority of major meteor shower radiants? The Geminids, the Leonids, the Perseids, the Quadrantids… all of these showers approach the Earth from above the celestial equator, and even from above the ecliptic plane. The Eta Aquarids are one of the very few major showers that goes against this trend.

Is it all just a coincidence? Perhaps. Like total solar eclipses, meteor showers are as much a product of our position in time as well as space. New streams are shed as comets visit the inner solar system, some for the very first time. These older trails interact with and are dispersed by subsequent passages near planets. The 12 year fluctuation of the Eta Aquarids is thought to be related to the orbit of Jupiter which has a similar period.

For example, one meteor shower known as the Andromedids was prone to epic storm outbursts until the early 20^th century. Now the stream is a mere trickle. Meteor showers evolve over time, and perhaps their seeming affinity for the northern hemisphere of our planet is a mere perception of our epoch. Maybe a future study could discern a bias due to the number of prograde versus retrograde cometary orbits, or perhaps statistical scrutiny could reveal that no such partiality actually exists.

All food for thought as you keep vigil these early May mornings for the meteoric “Drops from the Water Jar…” Be sure to post those meteor pics to the Universe Today’s Flickr forum, report those meteor counts to the International Meteor Organization, and tweet those fireball sightings to #Meteorwatch!

April 29, 2013December 23, 2015 by David Dickinson

Debunking Comet ISON Conspiracy Theories (No, ISON is Not Nibiru)

ISON as seen from Hubble. (credit: NASA)

Comets always seem to bring ‘em out of the wood work.

There’s a scene from the 1998 movie Deep Impact where the president, played by Morgan Freeman, reveals a terrible truth… the U.S. government has known for over a year that a doomsday comet is headed straight towards Earth, with Hollywood CGI destruction sure to follow.

While dramatic, the scenario is also extremely implausible. On any given evening, amateur astronomers are sweeping the skies using telescopes mounted in backyard observatories that are the envy of many major universities. This effort to discover comets is collaborative and worldwide. If the “Big One” were headed our way, even the likes of Morgan Freeman couldn’t keep it secret.

Trouble is, many unfounded claims are already making their way around the internet about this years’ much anticipated “Comet of the Century,” C/2012 S1 ISON.

Many of these conspiracy theories seem to be a recycling of last years’ Nibiru nonsense. The train of thought runs something like this: Does NASA know something that they’re not telling us? Why are they so interested in this comet? We’ve even had folks ask us why certain patches of Google Earth are “blacked out!”

What ARE they hiding, man?

It’s funny how pseudoscience seems to bubble to the top on YouTube, but I won’t give these conspiracy videos the exposure of the Universe Today platform. With hundreds of thousands of hits, they certainly don’t seem to need it. A simple YouTube search of “ISON” will scare up many wacky ideas about the comet.

In any event, we’ve already fielded several questions from friends and the public on the “dangers” posed by this comet, so we can only imagine that these will grow in intensity as the comet approaches the inner solar system, especially if it performs up to expectations.

What are some of the conspiracy theories out there about Comet ISON?

One currently circulating claim states that Comet ISON has “companions” that have been imaged trailing it. While comets do indeed fragment on occasion, the culprits that can be seen in the .gif animation circulating the internet are easily identified by photography experts as hot pixels in the camera.

Another even more extravagant claim is that Comet ISON will somehow appear “as bright as the Sun.” Even if Comet ISON reaches an expected magnitude equal to that of the full Moon at -13, it will do so when it is less than a degree from the Sun. Our Sun shines at magnitude -26.74, or over 158,000 times brighter, so it would be very difficult for this comet to compete with the Sun’s brightness in the daytime!

Others seem to worry that this comet — or particles from ISON — could impact Earth. Comet ISON will be making its inner solar system passage safely 0.426 A.U., or a little over 63 million kilometers from Earth even on its closest approach on December 26th. Scientists have defined this comet’s orbit very precisely, and it won’t hit Earth. So, no Comet ISON is not Nibiru — that ‘tenth planet’ destined to destroy Earth that conspiracy lovers can’t seem to let go of.

The debris — which might create a very nice meteor shower — is made up of extremely tiny grains of dust, no more than a few microns wide. Since they will be hitting Earth’s atmosphere at speeds up to 200,000 km/hr (125,000 miles per hour), the particles will burn up.

Here’s a video NASA released about the potential meteor shower from ISON:

Other claims focus on how this comet may cause earthquakes or wreak other untold havoc on Earth. This type of comet hysteria is nothing new. Name a bright comet in history, and you can find a historical event for a convenient tie-in. When haven’t there been earthquakes, pandemics, and wars in history? Plus, according to the US Geological Survey, on any given day there will be an average of 2,750 earthquakes around the world of which 275 are large enough to be felt by humans. But only about 100 earthquakes a year are large enough to cause any damage.

And so, its too easy to tie the “causes” of earthquakes and other events to comets in the sky. Comets have been seen before and during the Norman invasion of England in 1066, an outbreak of the Black Plague in London in 1665, and much more. Gary Kronk maintains a wacky and wonderful list of historical (and sometimes comical) comet “signs and omens” on his Cometography site.

Comet Lovejoy as seen from the International Space Station. — Another brilliant sungrazer, Comet Lovejoy as seen from the International Space Station on December, 2011. (Credit: NASA).

Halley’s Comet produced one of the first great comet hypes of the 20^th century with its 1910 passage. Ironically, another comet made a brilliant passage just a few months prior, which became known as the Great Comet of 1910. In fact, many viewers in the general public actually saw this comet and confused it with Halley’s! The recent discovery of cyanogen in the comet’s spectra sparked a panic in the public as hucksters made a small fortune hawking “comet pills” and gas masks to panicked buyers. Never mind that folks ingest more toxic carcinogens from their daily environment than are ever seeded by the tenuous tails of comets.

Another curious bit of hype sprung up in 2011 around Comet Elenin, which promptly broke up and dissipated without even putting on a show. And the supposed earthquakes that conspiracy theorists predicted? Well, the evidence speaks loudly: nothing happened. And the same will be true of Comet ISON. It won’t cause any earthquakes or other disasters. As Don Yeomans from NASA said about Comet Elenin, “It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean’s tides than comet Elenin ever will.”

So, what’s the harm in all the comet hysteria? Well, one only has to look at the mass suicide of the Heaven’s Gate cult in 1997 to realize that it can be no laughing matter. The suicide was sparked by the idea popularized on the late night Coast to Coast with Art Bell radio show that a spacecraft had been spotted following Comet Hale-Bopp.

Dozens of comets are discovered every year. A great majority are tiny iceballs in unfavorable orbits that never rise above magnitude +10 and are thus of little interest to backyard observers. A couple of times a year, a comet might reach magnitude +6 to +10 and become a fine binocular object.

When a discovery is made — be it by amateur or professional — the first task is to gain enough observations of the object to ascertain its orbit. Once again, we see the international collaborative methods employed by modern science. Already, the cosmic cat’s out of the bag as observatories worldwide make follow up measurements. There are no secrets about Comet ISON that hundreds of astronomers could keep quiet.

You get the idea... a 1687 leaflet depicting the havoc that a comet is sure to bring. (Wikimedia Commons image in the Public Domain). — You get the idea… a 1687 leaflet depicting the havoc that a comet is sure to bring. (Wikimedia Commons image in the Public Domain).

But here are some facts about Comet C/2012 S1 ISON. It was discovered last September by Russian amateurs Vitali Nevski and Artyom Novichonok while making observations for the International Scientific Optical Network (ISON), hence the comet’s name. At the time, it was farther than Jupiter and impossibly faint, but once ISON’s orbit was determined, astronomers realized the comet would pass only 1.1 million miles from center of the Sun (680,000 miles above its surface) on November 28, 2013.

Comet ISON belongs to a special category of comets called sungrazers. As the comet performs a hairpin turn around the Sun on that date, its ices will vaporize furiously in the intense solar heat. Assuming it defies death by evaporation, ISON is expected to become a brilliant object perhaps 10 times brighter than Venus, or maybe even brighter. But that would only occur for a brief time around at perihelion (closest approach to the Sun).

In the end, Comet ISON may put on a good show, but don’t believe the hype.

Comets are notoriously unpredictable when it comes to brightness estimations. To quote comet-hunter David Levy, “Comets are like cats… they have tails, and they do exactly what they want.” But they cannot, however, violate the laws of orbital mechanics!

The orbit and orientation of Comet ISON the day after Christmas 2013 on closest approach to the Earth. (Credit: NASA/JPL's Small-Body Database Browser). — The orbit and orientation of Comet ISON the day after Christmas 2013 on it closest approach to the Earth. (Credit: NASA/JPL’s Small-Body Database Browser).

April 24, 2013December 23, 2015 by David Dickinson

Comet Lemmon, Now in STEREO

Animation of Comet 2012 F6 Lemmon as seen from NASA's STEREO ahead spacecraft. (Credit: NASA/GFSC; animation created by Robert Kaufman).

An icy interloper was in the sights of a NASA spacecraft this past weekend.

Comet 2012 F6 Lemmon passed through the field of view of NASA’s HI2A camera as seen from its solar observing STEREO Ahead spacecraft. As seen in the animation above put together by Robert Kaufman, Comet Lemmon is now displaying a fine ion and dust tail as it sweeps back out of the inner solar system on its 10,750 year plus orbit.

Comet Lemmon has been a dependable performer for southern hemisphere observers early in 2013. As we reported earlier this month for Universe Today, this comet is now becoming a binocular object low in the dawn sky for northern hemisphere astronomers.

Comet Lemmon passed perihelion at 0.73 astronomical units from the Sun on March 24th. It’s currently in the +4^th to +5 magnitude range as it heads northward through the constellation Pisces.

NASA’s twin Solar TErrestrial RElations Observatory (STEREO) spacecraft often catch sungrazing comets as they observe the Sun. Known as STEREO A (Ahead) & STEREO B (Behind), these observatories are positioned in Earth leading and trailing orbits. This provides researchers with full 360 degree coverage of the Sun. Launched in 2006, STEREO also gives us a unique perspective to spy incoming sungrazing comets. Recently, STEREO also caught Comet 2011 L4 PanSTARRS and the Earth as the pair slid into view.

Another solar observing spacecraft, the European Space Agencies’ SOlar Heliospheric Observatory (SOHO) has been a prolific comet discoverer. Amateur comet sleuths often catch new Kreutz group sungrazers in the act. Thus far, SOHO has discovered over 2400 comets since its launch in 1995. SOHO won’t see PanSTARRS or Lemmon in its LASCO C3 camera but will catch a glimpse of Comet 2012 S1 ISON as it nears the Sun late this coming November.

Like SOHO and NASA’s Solar Dynamics Observatory, data from the twin STEREO spacecraft is available for daily perusal on their website. We first saw this past weekend’s animation of Comet Lemmon passing through STEREO’s field of view on the Yahoo STEREOHunters message board.

Here’s a cool but largely unrecognized fact about comets. As they move back out of the solar system, their dust tail streams out ahead of them, driven by the solar wind. I’ve even seen a few science fiction flicks get this wrong. We simply expect comets to always stream their tails out behind them!

Another observatory in our solar observing arsenal has also moved a little closer to operability recently. The Interface Region Imaging Spectrograph (IRIS) arrived at Vandenberg recently in preparation for launch this summer on June 26^th. IRIS will be deployed from a Pegasus XL rocket carried aloft by an L-1011. NuSTAR was launched in a similar fashion in 2012. A Pegasus XL rocket will also launch the TESS exoplanet hunting satellite in 2017.

Keep an eye out for Comet Lemmon as it emerges from the dawn twilight in the days ahead. Also, be sure to post those pics to Universe Today’s Flickr community, and keep tabs on the sungrazing action provided to us by SOHO and STEREO!

April 23, 2013April 26, 2016 by David Dickinson

A ‘Shallow’ Lunar Eclipse Coming on April 25

The very early partial phase of the 2010 December solstice total lunar eclipse. This week's shallow eclipse will appear similar at its maximum. (Photo by author)

Eclipse season is upon us this week with the first eclipse of 2013, a brief partial lunar eclipse.

The lunar eclipse on April 25, 2013 is a shallow one, meaning only a paltry 1.47% of the lunar limb will be immersed in the dark umbra or inner shadow of the Earth. Observers can expect to see only a dark diffuse edge of the inner shadow nick the the Moon as is grazes the umbra.

A partial lunar eclipse this shallow hasn’t occurred since May 3^rd, 1958 (0.9%) and won’t be topped until September 28^th, 2034 (1.4%). This is the second slightest partial lunar eclipse for this century.

Another term for this sort of alignment is known as a syzygy, a great triple-letter word score in Scrabble!

A video simulation of the eclipse:

The eclipse will be visible in its entirety from eastern Europe & Africa across the Middle East eastward to southeast Asia and western Australia. The eclipse will be visible at moonrise from South America to Western Europe and occurring at moonset for eastern Australia and the Far East. The partially eclipsed Moon will be directly overhead just off the northeastern coast of Madagascar. The eclipse will not be visible from North America.

Two eclipse seasons occur each year when the nodal points of the Moon’s orbit intersect the ecliptic while aligned with the position of the Sun and the Earth’s shadow. The Moon’s orbit is inclined 5.15° degrees with respect to the ecliptic, which traces out our own planet’s path around the Sun. If this intersection occurs near New or Full Moon, a solar or lunar eclipse occurs.

The visibility region of Thursday's partial lunar eclipse. — The visibility region of Thursday’s partial lunar eclipse (Credit: NASA/GSFC/F. Espenak).

If the Moon’s orbit was not inclined to our own, we’d get two eclipses per lunation, one solar and one lunar.

2013 has 5 eclipses, 3 lunar and 2 annular. The minimum number of eclipses that can occur in a calendar year is 4, and the maximum is 7, as will next occur in 2038.

The 3 lunar eclipses in 2013 are this week’s partial eclipse on April 25^th and two faint penumbral eclipses, one on May 25^th and another on October 18^th. There is no total lunar eclipse in 2013. The last one occurred on December 10^th 2011, and the next one won’t occur until April 15^th 2014, favoring the Pacific Rim region.

This eclipse will also set us up for the first solar eclipse of 2013, an annular eclipse crossing NE Australia (in fact crossing the path of last year’s total eclipse near Cairns) and the south Pacific on May 10th. The only solar totality that will touch the surface of the Earth in 2013 is the hybrid eclipse on November 3rd spanning Africa and the South Atlantic with a maximum totality of 1 minute & 40 seconds.

Contact times for the April 25 shallow eclipse:

P1-The Moon touches the penumbra-18:03:41 UT

U1-The Moon touches the umbra-19:54:04 UT

Mid-Eclipse-20:08:37.5 UT

U4 -The Moon quits the umbra-20:21:04 UT

P4-The Moon quits the penumbra- 22:11:23 UT

The length of the partial phase of the eclipse is exactly 27 minutes, and the length of the entire eclipse is 4 hours, 7 minutes and 42 seconds.

This particular eclipse is part of saros series 112 and is member 65 of 72.

This saros cycle began in 859 C.E. on May 20^th and will end in 2139 on July 12^th with a penumbral lunar eclipse. One famous member of this series was 52. This eclipse was one of many used by Captain James Cook to fix his longitude at sea on December 4^th 1778. Christopher Columbus also attempted this feat while voyaging to the New World. It’s a fun project that anyone can try!

I also remember watching the last eclipse in this series from South Korea on April 15^th 1995, a slightly better partial of 11.14%.

An occultation of the bright star Spica occurs just 20 hours prior as seen from South Africa across the southern Atlantic. This the 5th in a series of 13 occultations of the star by the Moon in 2013.

Occultation of Spica — The visibility region for the April 25th occultation of Spica. (Created by the Author using Occult 4.1.0.2).

The +2.8^th magnitude star Zubenelgenubi (Alpha Librae) is occulted by the waning gibbous Moon just 15 hours after the eclipse for Australia and the South Pacific.

Another occultation of a bright star with potential this week is +4.7^th magnitude Chi Virginis across North America on the morning of Wednesday, April 24^th centered on 4:24 UT.

Chi Virginis occultation — Visibility region for the occultation of Chi Virginis on April 24th. (Created by the author using Occult 4.1.0.2 software).

Also keep an eye out for +0.1 magnitude Saturn near the Full Moon. Saturn reaches opposition this weekend for 2013 on April 28^th

Full Moon occurs near mid-eclipse at 20:00 UT/16:00 EDT on April 25^th. Colloquial names for the April Full Moon are the Pink, Fish, Sprouting Grass, Egg, Seed, & Waking Moon.

Sure, the penumbral phases of an eclipse are subtle and may not be noticeable to the naked eye… but it is possible to see the difference photographically. Simply take a photo of the Moon before it enters the Earth’s penumbra, then take one during the penumbral phase and then another one after. Be sure to keep the ISO/f-stop and shutter speed exactly the same throughout. Also, this project only works if the eclipsed Moon is high in the sky throughout the exposures, as the thick air low to the horizon will discolor the Moon as well. Compare the shots; do you see a difference?

A penumbral eclipse would offer a good proof of concept test for hunting for transiting exoplanets as well, although to our knowledge, no one has ever attempted this.

Finally, calling out to all Universe Today readers in Madagascar. YOU may just be able to catch a transit of the International Space Station in front of the Moon just as the ragged edge of the umbra becomes apparent on the limb of the Moon. Check CALSky a day or so prior to the eclipse for a refined path… it would be an unforgettable pic!

The position of the ISS on April 25th at 19:48UT, just minutes before the partial pahse of the eclipse begins. (Credit: Orbitron). — The position of the ISS on April 25th at 19:48UT, just minutes before the partial phase of the eclipse begins. (Credit: Orbitron).

And if any ambitious observer is planning to live stream the eclipse, let us know and we’ll add your embed to this post. We do not expect an avalanche of web broadcasts, but hey, we’d definitely honor the effort! Slooh is usually a pretty dependable site for live eclipse broadcasts, and as of this writing seems to have broadcast scheduled in the cue.

Happy eclipse-spotting!

April 22, 2013December 23, 2015 by David Dickinson

The Curious History of the Lyrid Meteor Shower

The 2013 Lyrid meteors as seen from Windy Point Vista on Mt. Lemmon, Tucson Arizona. (Credit & copyright Sean Parker Photography. In the Universe Today flickr gallery).

Today we residents of planet Earth meet up with a meteor stream with a strange and bizarre past.

The Lyrid meteors occur annually right around April 21^st to the 23^rd. A moderate meteor shower, observers in the northern hemisphere can expect to see about 20 meteors in the early morning hours under optimal conditions. Such has been the case for recent years past, and this year’s presence of a waxing gibbous Moon has lowered prospects for this April shower considerably in 2013.

But this has not always been the case with this meteor stream. In fact, we have records of the Lyrids stretching back over the past 2,600 years, farther back than any other meteor shower documented.

The earliest account of this shower comes from a record made by Chinese astronomers in 687 BC, stating that “at midnight, stars dropped down like rain.” Keep in mind that this now famous assertion that is generally attributed to the Lyrids was made by mathematician Johann Gottfried Galle in 1867. It was Galle along with Edmond Weiss who noticed the link between the Lyrids and Comet C/1861 G1 Thatcher discovered six years earlier.

Comet Thatcher was discovered on April 5^th, 15 days before it reached perihelion about a third of an astronomical unit (A.U.) from the Earth. Comet Thatcher a periodic comet on a 415 year long orbital period.

But in the early to mid-19^th century, the very idea that meteor showers were linked to comets or even non-atmospheric phenomena was still hotly contested.

One singular event more than any other triggered this realization. The Leonid meteor storm of 1833 in the early morning hours of November 13^th was a stunning and terrifying spectacle for residents of the U.S eastern seaboard. This shower produces mighty outbursts, often topping a Zenithal Hourly Rate (ZHR) of over a 1,000 once every 33 to 34 years. I witnessed a fine outburst of the Leonids from Kuwait in 1998, and we may be in for a repeat performance from this shower around 2032 or 2033.

There is substantial evidence that the Lyrids may also do the same at an undetermined interval. On April 20^th 1803, one of the most famous accounts of a “Lyrid meteor storm” was observed up and down the United States east coast. For example, one letter to the Virginia Gazette states;

“From one until three, those starry meteors seemed to fall from every point in the sky heavens, in such numbers as to resemble a shower of sky rockets.”

Another account published in the Raleigh, North Carolina Register states that:

“The whole hemisphere as far as the extension of the horizon seemed illuminated; the meteors kept no particular direction but appeared to move in every way.”

A study of the 1803 Lyrid outburst by W.J. Fisher cites over a dozen accounts of the event and is a fascinating read. Viewers were also primed for the event by the dramatic Leonid storm of 1799 four years earlier.

Interestingly, the Moon was only one day from New phase on the night of the 1803 Lyrids. Prime meteor watching conditions.

An unrelated meteorite fall would also occur four years later over Weston, Connecticut on December 14^th, 1807 as recounted by Kathryn Prince in A Professor, A President, and a Meteor. These events would place Yankee politics at odds with the origin of meteors and rocks from the sky.

An apocryphal quote is often attributed to President Thomas Jefferson that highlights the controversy of the day, saying that “I would more easily believe that two Yankee professors would lie than that stones would fall from heaven.”

While both are of cosmogenous origin, no meteorite fall has ever been linked to a meteor shower, which is spawned by dust debris from comets. For example, many in the media erroneously speculated that the Sutter’s Mill meteorite that fell to Earth on the morning of April 22^nd, 2012 was in fact a Lyrid meteor.

But a Lyrid may be implicated in another unusual 19^th century observation. On April 24^th 1874, a professor Scharfarik of Prague, Czechoslovakia was observing the daytime First Quarter Moon with his 4” refractor. The good professor was surprised by an “Apparition on the disc of the Moon of a dazzling white star,” which was “quite sharp and without a perceptible diameter.” Possible suspects are a telescopic meteor moving towards or along the observers’ line of sight or perhaps a Lyrid impacting the dark limb of the Moon.

Moving into the 20^th century, rates for the Lyrids have stayed in the ZHR=20 range, with notable peaks of 100+ per hour noted by Japanese observers in 1922 and 100 per hour noted by U.S. observers in 1982.

It should also be noted that another less understood shower radiates from the constellation Lyra in mid-June. First noted Stan Dvorak while hiking in the San Bernardino Mountains in 1966, the June Lyrids produce about 8-10 meteors per hour from June 10 to the 21^st. The source of this newly discovered shower is thought to be Comet C/1915 C1 Mellish.

A June Lyrid may have even made its way into modern fiction. As recounted in a July 2004 issue of Sky & Telescope, researchers Marilynn & Donald Olson note the following line from James Joyce’s Ulysses:

“A star, precipitated with great apparent velocity across the firmament from Vega in the Lyre above the zenith.”

Joyce seems to be describing a June Lyrid decades before the shower was officially recognized. The constellation Lyra rides high in the early morning sky for mid-northern latitudes in the early summer months.

All interesting concepts to ponder as we keep an early morning vigil for the Lyrids this week. Could there be more Lyrid storms in the far off future, as Comet Thatcher reaches perihelion once again in the late 23^rd century? Could more historical clues of the untold history of this and other showers be awaiting discovery?

Somewhat closer to us in time and space, Paul Wiegert of the University of Ontario has also recently speculated that Comet 2012 S1 ISON may provoke a meteor shower on January 12^th, 2014. Regardless of whether ISON turns out to be the “Comet of the Century,” this could be one to watch out for!

April 19, 2013December 23, 2015 by David Dickinson

How Micrometeoroid Impacts Pose a Danger for Today’s Spacewalk

Astronauts perform an EVA outside of the ISS during STS-110. (Credt: NASA).

Video streaming by Ustream

Our very own International Space Station is in the cosmic crosshairs.

As cosmonauts are to begin Extra Vehicular Activity (EVA) this morning to perform routine maintenance, an article reminding us of the hazards of such activity came to us via NASA’s Orbital Debris Quarterly Newsletter.

The problem is Micrometeoroid and Orbital Debris (MMOD) impacts. These are nothing new. Pits and tiny cratering has been observed during post-flight inspections of space shuttle orbiters. But this is the first time we’d seen talk of damage caused by tiny impacts on the exterior of the International Space Station.

The handrails are a particularly sensitive area of concern.

The study examined damage incurred on handrails exposed to the environment of space for years on end. These present a hazard to spacewalking astronauts who rely on the handles to move about. These craters often become spalled, presenting a sharp metal rim raised from the surface of the handle.

Close-up of a micro-meteoroid impact on a handrail. (Credit: NASA/JSC Image & Science Analysis Group).

Of course, these razor sharp rims present a problem, especially to space suit gloves. One 34.8 centimeter long handrail returned on the final Space Shuttle mission STS-135 had six impact craters along its length. The handrail had been in service and exposed to the vacuum of space for 8.7 years.

Craters as large as 1.85 millimetres (mm) in diameter with raised lips of 0.33mm have been observed on post-inspection. In studies conducted by NASA engineers, craters with lip heights as little as 0.25mm have been sufficient to snag and tear spacesuit gloves.

There have also been reported incidents of glove tears during EVAs conducted from the ISS over the years. For example, the report cites a tear noticed by astronaut Rick Mastracchio during STS-118 that cut the EVA short.

Analysis of an impact seen on STS-122. (Credit: NASA/JSC Image & Science Analysis Group).

To protect astronauts and cosmonauts during EVAs, the following measures have been instituted:

– Toughening space suit gloves by adding reinforcement to areas exposed to potential MMOD damage.

– Monitoring and analyzing MMOD impacts along handrails and maintaining a database of problem areas.

– Equipping spacewalkers with the ability to cover and/or repair hazardous MMOD areas during spacewalks.

The studies were carried out by the Johnson Space Center Hypervelocity Impact Technology Group in conjunction with a test facility at White Sands, New Mexico. Astronaut Rick Mastracchio can also be seen talking about the hazards of spacewalking on this video.

Today’s 6 hour EVA by cosmonauts Vinogradov & Romanenko begins at 14:06 UT 10:06AM EDT.

This will be the 32^nd Russian EVA from the International Space Station and will use the Pirs hatch on Zvezda.

Tasks include retrieving and installing experiment packages and replacing a defective retro-reflector device on the station’s exterior. The device is a navigational aid necessary for the Albert Einstein ATV-4 mission headed to the ISS on June 5th.

Progress 51P is also scheduled to launch towards the ISS next week on April 24 for docking on April 26th.

Debris in Low Earth Orbit is becoming an increasing concern. The Chinese anti-satellite test in 2007 and the collision of Kosmos 2251 and Iridium 33 in 2009 have increased hazards to the ISS. Many fear that a tipping point, known as an ablation cascade, could eventually occur with one collision showering LEO with debris that in turn trigger many more. The ISS was only finished in 2011, and it would be a tragic loss to see it abandoned due to a catastrophic collision only years after completion.

More than once, ISS crew members have sat out a debris conjunction that was too close to call in their Soyuz life boats, ready to evacuate the station if necessary. DAMs (Debris Avoidance Maneuvers) are now common for the ISS throughout the year.

Several ideas have been proposed to deal with space debris. In the past year, NanoSail-2D demonstrated the ability to deploy a solar sail from a satellite for reentry at the end of a spacecraft’s life span. Such technology may be standard equipment on future satellites.

Expect reentries to increase as we near the solar maximum for cycle #24 in late 2013 & early 2014. This occurs because the exosphere of Earth “puffs out” due to increased solar activity and increases drag on satellites in low Earth orbit.

All food for thought as we watch today’s EVA… space travel is never routine!

The April 2013 edition of the Orbital Debris Quarterly News is available for free online.

April 18, 2013April 26, 2016 by David Dickinson

Rise of the PhoneSats

Satellites can now fit in the palm of your hand.

Known as Cubesats, several of these tiny but cost-effective payloads use off-the-shelf technology that you may currently carry in your pocket. In fact, engineers have put out a call for app designers to write programs for these tiny micro-satellites. Four of this new breed of satellites are part of the Antares A-One mission and another four are slated to launch tomorrow atop a Soyuz rocket from Plesetsk along with the Bion M-1 payload.

Yesterday’s launch of Orbital Sciences’ Antares rocket was scrubbed with minutes to go due to the premature retraction of an umbilical. Current plans call for a 48 hour turnaround with a new launch window opening Friday night on April 19^th at 5:00 PM EDT/ 21:00 UT.

Cubesats are nothing new. As technology becomes miniaturized, so have the satellites that they’re contained in. Cubesats have even been deployed from the International Space Station.

The primary goal of the Antares A-One mission is to deploy a test mass into low Earth Orbit that simulates the Cygnus spacecraft. If all goes well, Cygnus is set to make its first flight to the ISS this summer.

But also onboard are the three unique payloads; the PhoneSat-1a, 1b & 1c cubesats and the Dove 1 cubesat.

As the name implies, the PhoneSat series of satellites are each constructed around a Nexus Smartphone and operate using Google’s very own Android operating system. The mission serves as NASA’s test bed for the concept. The phone system will monitor the orientation of the satellites. The PhoneSats will also use their off-the-shelf built-in cameras to take pictures of the Earth from orbit.

A separate watchdog circuit will reboot the phones if necessary. The PhoneSats are expected to last about a week in orbit until their batteries die. One of the PhoneSats is equipped with solar panels to test rechargeable technology for the platform.

Two of the nano satellites are built around a Samsung Nexus S and the other around a HTC Nexus Smartphone. The satellites will also use the SD card for info storage plus the 3-axis magnetometer and accelerometer incorporated into the phones for measurements and orientation.

A PhoneSat 1.0 during a balloon test flight. (Credit: NASA).

Dove-1 will test a similar technology. It is built around a low-cost bus using off-the-shelf components. Each of the three PhoneSats cost less than $3,500 dollars U.S. to build.

Amateur radio operators will also be able to monitor the satellites as well. The PhoneSats will transmit at 437.425 MHz. Information will also available to track them in real time on the web once they’re deployed.

The two PhoneSat 1.0 satellites are dubbed Graham and Bell and will transmit every 28 and 30 seconds, and the one PhoneSat 2.0 satellite is named Alexandre and will transmit every 25 seconds.

The PhoneSat 2.0 series will also employ magnets that interact with the Earth’s magnetic field. A future application of this could include use of a PhoneSat for a possible heliophysics mission.

Although the Antares A-One mission is aiming to place the Cygnus test mass and the Cubesats in an inclination of 51.6° degrees similar to the ISS, it will not be following the ISS in its orbit and won’t present a hazard to the station.

The goal of NASA’s PhoneSat team based out of the Ames Research Center at Moffett Field California is to “release early and often.” Missions like Antares A-One present a unique opportunity for the teams to get “piggyback payloads” into orbit. To this end, NASA’s Cubesat Launch Initiative (CSLI) issues periodic calls for teams across the nation to make proposals and build tiny satellites.

Basic dimensions of a cubesat are 10x10x14 centimetres (for comparison, a CD jewel case is about 14×12 cm) and must weigh less than 1.33 kilograms for 1U, 2U & 3U variants. Up to 14kg is allowed for 6U models. Cubesats are deployed from a Poly-Picosatellite Deployer, or P-Pod.

Another set of cubesats is also slated to launch tomorrow from Plesetsk. The primary payload of the mission is deployment of the Bion M-1 biological research satellite. Bion M-1 will carry an assortment of organisms including lizards, mice and snails for a one month mission to study the effects of a long duration spaceflight on micro-organisms.

The Bion M-1 mission will also deploy the AIST microsatellite built by students of Samara Aerospace University, & BeeSats 2 & 3 provided by the Technical University of Berlin. A twin of the Dove-1 satellite launching on Antares named Dove-2 is also onboard.

One of the micro-satellites named OSSI-1 is of particular interest to backyard satellite trackers. Part of the Open Source Satellite Initiative, OSSI-1 was developed by radio amateur and artist Hojun Song. In addition to a Morse Code beacon, OSSI-1 will also contain a 44 watt optical LED beacon that will periodically be visible to observers on Earth.

Another similar project, FITSAT-1, has been tracked and imaged by observers in recent months. Follow the AmSat-UK website for predictions and visibility prospects of OSSI-1 after launch and deployment. FITSAT-1 has been visible with binoculars only, but OSSI-1 may just be visible to the unaided eye during shadow passes while it’s operational.

It will be interesting to watch these “home-brewed” projects take to orbit. The price tag and the technology is definitely within reach of a sufficiently motivated basement tinker or student team with an idea. Hey, how about the world’s first free-flying “Amateur Space Telescope?” Just throwing that out there!

April 16, 2013December 23, 2015 by David Dickinson

How to Spot the Antares Launch from NASA Wallops on Wednesday

Sighting prospects for the US Eastern Seaboard during the ascent of Antares. (Credit: The Orbital Sciences Corporation).

A space launch marking a new era is departing from the Virginia coast this Wednesday evening, and if you live anywhere along a wide area of the US Eastern seaboard, you’ll have a great opportunity to witness the launch with your own eyes. Here’s all the information you’ll need to see it, plus some tips for capturing it with your camera.

Orbital Sciences’ Antares rocket will launch from Pad 0A at NASA’s Mid-Atlantic Regional Spaceport based on Wallops Island, Virginia. This will mark not only the first launch of Antares, but the first orbital launch of a liquid-fueled rocket from Wallops. The launch window runs from 5:00 to 8:00 PM EDT (21:00-24:00 UT).

There were some concerns when a technical anomaly shutdown a “Wet Dress Rehearsal” test this weekend at T-16 minutes, but Orbital Sciences has stated that the problems have been resolved and the launch is pressing ahead as planned.

Space shots are a familiar sight to the residents of the Florida Space Coast, but will provide a unique show for residents of the U.S. central Atlantic region. The launch of Antares from Wallops will be visible for hundreds of miles and be over 10° above the horizon for an arc spanning from Wilmington, North Carolina to Washington D.C. and north to the New York City tri-state area as it heads off to the southeast. Antares is a two stage rocket with a 1^st stage liquid fueled engine and a solid-fueled 2^ndstage. The primary mission for Wednesday’s Antares A-One flight will be to demonstrate the ability for the Antares rocket to place a payload into orbit. If all goes well, Orbital Sciences will join SpaceX this summer in the select club of private companies with the ability provide cargo delivery access to the International Space Station in Low Earth Orbit.

Antares heads to orbit. Artist's concept. (Credit: Orbital Sciences Corperation). — Antares heads to orbit. Artist’s concept. (Credit: Orbital Sciences Corporation).

Antares will deploy a dummy mass simulating the Cygnus module. Also onboard are the Phonesat-1a, -1b, and -1c micro-cubesats and the Dove 1 satellite.

Be sure to watch for the launch of Antares if you live in the region. Find a spot with a low uncluttered eastern horizon and watch from an elevated rooftop or hilltop location if possible. I live a hundred miles west of Cape Canaveral and I’ve followed launches all the way through Main Engine Cutoff and first stage separation with binoculars.

Be sure to also follow the launch broadcast live for any last minute delays via NASA TV or Universe Today will have a live feed as well. Antares is aiming to put the Cygnus test mass in a 250 x 300 kilometre orbit with a 51.6° inclination. This is similar to what will be necessary to head to the ISS, but this week’s launch will not be trailing the ISS in its path. This also means that the launch window can be extended over three hours rather than having to be instantaneous.

If the launch goes at the beginning of the window, the local sun angle over the launch facility will be 30° to the west. Sunset at Wallops on the evening of April 17^th occurs at 7:41PM EDT, meaning we could be in for a photogenic dusk launch of Antares if it stretches to the end of the target window.

And speaking of which, a pre-sunset launch means short daytime exposure settings for photography. Be prepared to switch over for dusk conditions if the launch extends into the end of the window. Conditions during twilight can change almost moment-to-moment. One of the most memorable launches we witnessed was the pre-dawn liftoff of STS-131 on April 5^th, 2010:

The predawn launch of STS-131 as seen from 100 miles west. (Photo by author).

Once in orbit, the launch of Antares should generate four visible objects; the test mass payload, the two clam-shell fairings, and the stage two booster. This configuration is similar to a Falcon 9/Dragon launch, minus the solar panel covers. These objects should be visible to the naked eye at magnitudes +3 to +5. The cubesat payloads are tiny and below the threshold of naked eye visibility.

Preliminary visibility for the objects will favor latitudes 0-30° north at dusk to 10-40° at dawn. Keep in mind these predictions could change as the launch window evolves. The next NORAD tracking ID in the queue is 2013-015A. Yesterday’s launch of Anik G1 from Baikonur was just cataloged today as 2013-014A plus associated hardware. The weather is forecast to be 45% “go” for tomorrow’s launch. In the event of a scrub, the next launch window for Antares is April 18-21st.

First orbit of the Cygnus test mass; shadow orientation of the Earth assumes a nominal launch at 22:00UT on April 17th. (Created by the author using Orbitron. TLEs courtesy of (name) — First orbit of the Cygnus test mass; shadow orientation of the Earth assumes a nominal launch at 22:00 UT on April 17th. (Created by the author using Orbitron. Two-Line Elements courtesy of Henry Hallam).

It’ll be exciting to follow this first flight of Antares and its first scheduled mission to the International Space Station this summer. Also watch for the first ever lunar mission to depart Wallops on August 12 with the launch of the Lunar Atmosphere and Dust Environment Explorer (LADEE).

Finally, if you’ve got a pass of the International Space Station this week, keep an eye out for Progress M-17M currently about 10 minutes ahead of the station in its orbit. The unmanned Progress vehicle just undocked yesterday from the station and will be conducting a series of experiments monitoring the interactions of its thrusters with the ionosphere before burning up on reentry over the South Pacific on April 21^st.

A pass of the ISS over UK tonite (April 16th) with Progress leading at 20:30UT. (Created by the author in Orbitron).

The ISS and more can be tracked using Heavens-Above. Also, we’ll be tweeting all of the updates and orbital action as it evolves as @Astroguyz. Let us know of those launch sightings both near and far. It’ll be interesting to see what, if any, impact launches visible to a large portion of the U.S. population will have on the public’s perception of spaceflight. Be sure to look up tomorrow night!

April 14, 2013April 26, 2016 by David Dickinson

Mysterious Moon Flashes: Could the Transient Lunar Phenomena be Linked to the Solar Cycle?

The Moon, our nearest natural satellite. (Photo by author).

A key mystery in observational lunar astronomy may be at least partially resolved.

An interesting study appeared recently in the British Astronomical Association’s (BAA) March 2013 edition of their Lunar Section Circular. The study is one of the most comprehensive looks at possible connections between Transient Lunar Phenomena and the Solar Cycle.

Collection of TLP reports analyzed by Barbara Middlehurst & Sir Patrick Moore. The red dots indicate reddish events, the yellow one other colored events. (Wikimedia Commons image in the Public Domain). — Collection of TLP reports analyzed by Barbara Middlehurst & Sir Patrick Moore. The red dots indicate reddish events. The yellow ones represent other colored events. (Wikimedia Commons image in the Public Domain).

Transient Lunar Phenomena (or TLPs) are observations collected over the years of flashes or glows on the Moon. Since these phenomena often rely on a report made by a solitary observer, they have been very sparsely studied.

The term itself was coined by Sir Patrick Moore in 1968. One of the very earliest reports of a TLP event was the flash seen on the dark limb of the waxing crescent Moon by Canterbury monks in 1178.

Other reports, such as a daylight “star near of the daytime crescent Moon” seen by the residents of Saint-Denis, France on January 13, 1589 was almost certainly a close conjunction of the planet Venus. Bright planets such as Venus can be easily seen next to the Moon in the daytime.

A daytime Moon and Venus as seen from France on January 13th, 1589. (Created by the author in Starry Night).

A stunning illusion also occurs when the Moon occults, or passes in front of a bright star or planet. In fact, there’s a name for this psychological phenomenon of a bright star seeming to “hang” between the horns of the Moon just prior to an occultation, known as the Coleridge Effect. This takes its name from a line in Coleridge’s Rime of the Ancient Mariner;

“Till clomb above the eastern bar, the horned Moon with one bright star,

Within nether tip.”

Okay, we’ve never seen the “horned Moon clomb,” either. But this does describe a real illusion often seen during an occultation. The mind thinks that gap between the horns of the Moon should be transparent, and the lingering planet or star seems to cross that space on the dark limb, if only for a second. Incidentally, South American residents will get to check this out during the next occultation of Venus this year on September 8th.

So, what does this have to do with the 11-year solar cycle? Well, when you strip away many of the dubious observations of TLPs over the years, a core of well- documented events described by seasoned observers remains. Anyone who has sketched such a complex object as the Moon realizes that fine detail becomes apparent on scrutiny that may be missed in a casual glance. But one persistent assertion that has gone around the astronomical community for years is that an increase in the number of TLP events is linked to the peak of the solar cycle.

This was first suggested in 1945 by H. Percy Wilkins. A later study by Barbara Middlehurst in 1966 disproved the idea, citing no statistical correlation between sunspot activity and TLPs.

Of course, pundits have tried unsuccessfully to link the solar cycle to just about everything, from earthquakes to human activity to booms and busts of the stock market. Most flashes on the dark limb of the Moon are suspected to be meteorite impacts. In fact, the advent of high-speed photography has been able to reveal evidence for lunar strikes during intense meteor showers such as the Leonids and Geminids.

Flash of a Leonid impact captured on the limb of the Moon in 2006. Click image to see animation. (Credit: NASA Meteoroid Environment Office).

What’s at little less clear are the source of luminous “hazes” or “glows” noted by observers. Keep in mind; we’re talking subtle effects noted after meticulous study. NASA even commissioned a study of TLPs named Project Moon-Blink during the early Apollo program. About a third of TLP events have been observed near the bright crater Aristarchus. Researchers even managed to get Neil Armstrong to make an observation of the crater during a pass on Apollo 11. He noted that “there’s an area that is considerably more illuminated than the surrounding area. It seems to have a slight amount of fluorescence.”

Aristarchus crater (arrowed) near Full Moon. Note how bright it is compared to the surrounding terrain. (Photo by Author). — A crater with a relatively high albedo (Proclus, arrowed) near Full Moon. Note how bright it is compared to the surrounding terrain. (Photo by Author).

But what’s interesting in the recent BAA study conducted by Jill Scambler is the amount of data that was available. The study was a comprehensive analysis of TLPs noted by the BAA, the Association of Lunar and Planetary Observers (ALPO) and NASA from 1700 to 2010. Observations were weighted from 1 to 5, with 1 for reports from inexperienced observers to 5 for definitive and unambiguous TLP events.

The periodogram analysis comparing the frequency of TLPs with the sunspot cycle utilized a tool available from NASA’s Exoplanet Database to evaluate the data. If there was any mechanism whereby TLPs were being generated by solar activity, it had been suggested previously by Wilkins that perhaps out-gassing was being caused be solar irradiation or lunar dust was becoming electrostatically charged and suspended.

In fact, Surveyor 7 witnessed such a phenomenon during lunar twilight. To date, no human has witnessed a sunrise or sunset from the surface of the Moon, although astronauts witnessed several from lunar orbit.

"Horizon glow" as imaged from the lunar surface during twilight. (Credit: NASA). — “Horizon glow” as imaged from the lunar surface during twilight. (Credit: NASA).

The final conclusion of the BAA study cites that “Although there are theories that might infer that TLP would be more frequent during solar activity, from a sunspot cycle perspective there is no evidence to support this.”

The report provides an interesting perspective on the topic, especially with solar cycle 24 peaking over the next year. It also seems that reports of TLPs have declined in past decades. One of the most famous examples was the flash imaged on the Moon (thought to be a Leonid) by Leon Stuart in 1953. But in the modern era of astrophotography with the Moon under nearly continuous scrutiny, where are all the images of TLPs?

Granted, a core number (2%) of events suggest evidence of real activity on a Moon that we most often think of as geologically dead. As for the spurious sightings, it helps to recall the number of “sightings” in the 19^th century of Vulcan transiting the face of the Sun. Where is Vulcan today, with the Sun being monitored around the clock?

We’re not immune to this sort of “echo effect” in the modern world of astronomy, either. For example, whenever an impact scar or flash is noted on Jupiter, as occurred in 2009 and 2012, other sightings are “seen” throughout the solar system. A similar psychological phenomenon occurred when Comet Holmes brightened in 2007. For a time, reports flying around the Internet suggested many comets where suddenly increasing in brightness!

It also interesting to note that many features such as Aristarchus and Ina Caldera also have a high brightness or albedo. Although the Full Moon seems pearly white, the albedo of the Moon is actually quite low at (13%), about that of worn asphalt. Bright ejecta and rays tend to stand out, especially approaching a Full Moon, such as occurs on May 25^th.

You can even enhance the saturation of those lunar pics to bring out subtle color and reveal that the Moon isn’t as monochromatic as it appears to the naked eye;

A false-colored gibbous Moon enhanced to bright out subtle color. (Photo by author). — A false-colored gibbous Moon enhanced to bring out subtle color. (Photo by author).

Kudos to the team at the BAA for casting a critical scientific eye on a little studied phenomenon. Perhaps missions such as the Lunar Atmosphere and Dust Environment Explorer (LADEE) departing for the Moon this summer will shed more light on the curious nature of Transient Lunar Phenomena.

-The study can be read in the March 2013 edition of the British Astronomical Association’s Lunar Section Circular available as a free pdf.

April 10, 2013December 23, 2015 by David Dickinson

New Exoplanet-Hunting Mission to launch in 2017

Artist's rendition of TESS in space. (Credit: MIT Kavli Institute for Astrophysics Research).

Move over Kepler. NASA has recently green-lighted two new missions as part of its Astrophysics Explorer Program.

These come as the result of four proposals submitted in 2012. The most anticipated and high profile mission is TESS, the Transiting Exoplanet Survey Satellite.

Slated for launch in 2017, TESS will search for exoplanets via the transit method, looking for faint tell-tale dips in brightness as the unseen planet passes in front of its host star. This is the same method currently employed by Kepler, launched in 2009. Unlike Kepler, which stares continuously at a single segment of the sky along the galactic plane in the direction of the constellations Cygnus, Hercules, and Lyra, TESS will be the first dedicated all-sky exoplanet hunting satellite.

The mission will be a partnership of the Space Telescope Science Institute, the MIT Lincoln Laboratory, the NASA Goddard Spaceflight Center, Orbital Sciences Corporation, the Harvard-Smithsonian Center for Astrophysics and the MIT Kavli Institute for Astrophysics and Space Research (MKI).

TESS will launch onboard an Orbital Sciences Pegasus XL rocket released from the fuselage of a Lockheed L-1011 aircraft, the same system that deployed IBEX in 2008 & NuSTAR in 2012. NASA’s Interface Region Imaging Spectrograph (IRIS) will also launch using a Pegasus XL rocket this summer in June.

An Orbital Sciences Pegasus XL rocket attached to the fuselage of an L1011 for the launch of IBEX. (Credit: NASA).

“TESS will carry out the first space-borne all-sky transit survey, covering 400 times as much sky as any previous mission. It will identify thousands of new planets in the solar neighborhood, with a special focus on planets comparable in size to the Earth,” said George Riker, a senior researcher from MKI.

TESS will utilize four wide angle telescopes to get the job done. The effective size of the detectors onboard is 192 megapixels. TESS is slated for a two year mission. Unlike Kepler, which sits in an Earth-trailing heliocentric orbit, TESS will be in an elliptical path in Low Earth Orbit (LEO).

TESS will examine approximately 2 million stars brighter than 12^th magnitude including 1,000 of the nearest red dwarfs. Not only will TESS expand the growing catalog of exoplanets, but it is also expected to find planets with longer orbital periods.

One dilemma with the transit method is that it favors the discovery of planets with short orbital periods, which are much more likely to be seen transiting their host star from a given vantage point in space.

TESS will also serve as a logical progression from Kepler to later proposed exoplanet search platforms. TESS will also discover candidates for further scrutiny by as the James Webb Space Telescope to be launched in 2018 and the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrometer based at La Silla Observatory in Chile.

Artist's conception of NICER on the exterior of the International Space Station. (Credit: NASA). — Artist’s conception of NICER on the exterior of the International Space Station. (Credit: NASA).

Also on the board for launch in 2017 is NICER, the Neutron Star Interior Composition Explorer to be placed on the exterior of the International Space Station. NICER will employ an array 56 telescopes which will collect and study X-rays from neutron stars. NICER will specialize in the study of a particular sub-class of neutron star known as millisecond pulsars. The X-ray telescopes are in a configuration utilizing a set of nested glass shells looking like the layers of an onion.

Observing pulsars in the X-ray range of the spectrum will offer scientists tremendous insight into their inner workings and structure. The International Space Station offers a unique vantage point to do this sort of science. Like the Alpha Magnetic Spectrometer (AMS-02), the power requirements of NICER dictate that it cannot be a free-flying satellite. X-Ray astronomy must also be done above the hindering effects of the Earth’s atmosphere.

NICER will be deployed as an exterior payload aboard an ISS ExPRESS Logistics Carrier. These are unpressurized platforms used for experiments that must be directly exposed to space.

Another fascinating project working in tandem with NICER is SEXTANT, the Station Explorer for X-ray Timing And Navigation Technology. This project seeks to test the precision of millisecond pulsars for interplanetary navigation.

“They (pulsars) are extremely reliable celestial clocks and can provide high-precision timing just like the atomic signals supplied through the 26-satellite military operated Global Positioning System (GPS),” said NASA Goddard scientist Zaven Arzoumanian. The chief difficulty with relying on this system for interplanetary journeys is that the signal gets progressively weaker the farther you travel from the Earth.

“Pulsars, on the other hand, are accessible in virtually every conceivable flight regime, from LEO to interplanetary and deepest space,” said NICER/SEXTANT principle investigator Keith Gendreau.

Both NICER and TESS follow the long legacy of NASA’s Astrophysics Explorer Program, which can be traced all the way back to the launch Explorer 1. This was the very first U.S. satellite launched in 1958. Explorer 1 discovered the Van Allen radiation belts surrounding the Earth.

(from left) William Pickering, James Van Allen, and Wernher von Braun hold aloft a mock up of Explorer 1 shortly after launch. (Credit NASA/JPL-Caltech. — (From left) William Pickering, James Van Allen, and Wernher von Braun hold aloft a mock up of Explorer 1 shortly after launch. (Credit NASA/JPL-Caltech).

“The Explorer Program has a long and stellar history of deploying truly innovative missions to study some of the most exciting questions in space science,” stated NASA associate administrator for science John Grunsfeld. “With these missions, we will learn about the most extreme states of matter by studying neutron stars and we will identify many nearby star systems with rocky planets in the habitable zones for further study by telescopes such as the James Webb Space Telescope.”

Of course, Grunsfeld is referring to planets orbiting red dwarf stars, which will be targeted by TESS. These are expected have a habitable zone much closer to their primary star than our own Sun. It has even been suggested by MIT scientists that the first exoplanets visited by humans on some far off date might be initially discovered by TESS. The spacecraft may also discover future targets for follow up spectroscopic analysis, the best chance of discovering alien life on an exoplanet in the next 50 years. One can imagine the excitement that a positive detection of a chemical exclusive to life as we know it such as chlorophyll in the spectra of a far of world would generate. More ominously, detection of such synthetic elements as plutonium in the atmosphere of an exoplanet might suggest we found them… but alas, too late.

But on a happier note, it’ll be exciting times for space exploration to see both projects get underway. Perhaps human explorers will indeed one day visit the worlds discovered by TESS… and use navigation techniques pioneered by SEXTANT to do it!