A new study based on data from Sloan Digital Sky Survey (SDSS) shows how certain exoplanets are dominated by minerals like olivine and garnet. Credit: NASA
The hunt for exoplanet has revealed some very interesting things about our Universe. In addition to the many gas giants and “Super-Jupiters” discovered by mission like Kepler, there have also been the many exoplanet candidate that comparable in size and structure to Earth. But while these bodies may be terrestrial (i.e. composed of minerals and rocky material) this does not mean that they are “Earth-like”.
For example, what kind of minerals go into a rocky planet? And what could these particular compositions mean for the planet’s geological activity, which is intrinsic to planetary evolution? According to new study produced by a team of astronomers and geophysicists, the composition of an exoplanet depends on the chemical composition of its star – which can have serious implications for its habitability.
The Apache Point Observatory Galactic Evolution Experiment (APOGEE), which collects spectrographic information on distant stars. Credit: astronomy.as.virginia.edu
Using the Apache Point Observatory Galactic Evolution Experiment (APOGEE), which is part of the Sloan Digital Sky Survey (SDSS) Telescope at Apache Point Observatory, they examined spectrographic information obtained from 90 star systems – which were also observed by the Kepler Mission. These systems are of particular interest to exoplanet hunters because they have been shown to contain rocky planets.
As Teske explained during the course of the presentation, this information could help scientists to place further constraints on what it takes for a planet to be habitable. “[O]ur study combines new observations of stars with new models of planetary interiors,” she said. “We want to better understand the diversity of small, rocky exoplanet composition and structure — how likely are they to have plate tectonics or magnetic fields?”
Focusing on two star systems in particular – Kepler 102 and Kepler 407 – Teske demonstrated how the composition of a planet has a great deal to do with the composition of its star. Whereas Kepler 102 has five known planets, Kepler 407, has two different planets – one gaseous and the other terrestrial. And while Kepler 102 is quite similar to our Sun (slightly less luminous), Kepler 407 has close to the same mass (but a lot more silicon).
In order to understand what consequences these differences could have for planetary formation, the SDSS team turned to a team of geophysicists. Led by Cayman Unterborn from Arizona State University, this team ran computer models to see what kinds of planets each system would have. As Unterborn explained:
“We took the star compositions found by APOGEE and modeled how the elements condensed into planets in our models. We found that the planet around Kepler 407, which we called ‘Janet,” would likely be rich in the mineral garnet. The planet around Kepler 102, which we called ‘Olive,’ is probably rich in olivine, like Earth.”
Artist rendition of interior compositions of planets around the stars Kepler 102 and Kepler 407. Credit: Robin Dienel/Carnegie DTM
This difference would have considerable impact on planetary tectonics. For one, garnet is lot more rigid than olivine, which would mean “Janet” would experience less in the way of long-term plate tectonics. This in turn would mean that processes that are believed to be essential to life on Earth – like volcanic activity, atmospheric recycling, and mineral exchanges between the crust and mantle – would be less common.
This raises additional questions about the habitability of “Earth-like” planets in other star systems. In addition to being rocky and having strong magnetic fields and viable atmospheres, it seems that exoplanets also need to have the right mix of minerals in order to support life – life as we know it, at any rate. What’s more, this kind of research also helps us to understand how life came to emerge on Earth in the first place.
Looking forward, the research team hopes to extend their study to include all the 200,000 stars surveyed by APOGEE to see which could host terrestrial planets. This will allow astronomers to determine the mineral composition of more rocky worlds, thus helping them to determine which rocky exoplanets are “Earth-like”, and which are just “Earth-sized”.
NASA’s new announcement entails awarding an additional four crew rotation missions each to commercial partners, Boeing and SpaceX, on top of the two demonstration fights previously awarded to each company under the agency’s Commercial Crew Program (CCP) initiative, in a Jan. 3 statement.
However, the newly awarded crew rotation missions will only take place after NASA has certified that each provider is fully and satisfactorily meeting NASA’s long list of stringent safety and reliability requirements to ensure the private missions will be safe to fly with humans aboard from NASA and its partner entities.
And NASA officials were careful to point out that these orders “do not include payments at this time.”
In other words, NASA will pay for performance, not mere promises of performance – because human lives are on the line.
“They fall under the current Commercial Crew Transportation Capability contracts, and bring the total number of missions awarded to each provider to six,” NASA officials announced.
Hull of the Boeing CST-100 Starliner Structural Test Article (STA)- the first Starliner to be built in the company’s modernized Commercial Crew and Cargo Processing Facility high bay at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
The goal of the CCP program is to ensure robust and reliable crew transportation to the International Space Station in this decade and beyond – using American rockets and capsules launching from American soil.
A further goal is to end America’s sole reliance on Russia for transporting American astronauts to and from the space station using Russia’s Soyuz crew capsules.
Since the forced retirement of NASA’s Space Shuttle’s in July 2011, NASA astronauts and its partners have been 100% dependent on Russia for rides to space – currently to the tune of over $80 million per seat.
By awarding these new contracts, Boeing and SpaceX should be able to plan further ahead in the future, order long lead time hardware and software, and ultimately cut costs through economy of scale.
“Awarding these missions now will provide greater stability for the future space station crew rotation schedule, as well as reduce schedule and financial uncertainty for our providers,” said Phil McAlister, director, NASA’s Commercial Spaceflight Development Division, in a statement.
“The ability to turn on missions as needed to meet the needs of the space station program is an important aspect of the Commercial Crew Program.”
Boeing and SpaceX are building private spaceships to resume launching US astronauts from US soil to the International Space Station in 2018. Credit: NASA
Boeing and SpaceX were awarded contracts by NASA Administrator Charles Bolden in September 2014 worth $6.8 Billion to complete the development and manufacture of the privately developed Starliner CST-100 and Crew Dragon astronaut transporters, respectively, under the agency’s Commercial Crew Transportation Capability (CCtCap) program and NASA’s Launch America initiative.
The CCP initiative was started back in 2010 under the Obama Administration to replace NASA’s outgoing space shuttle orbiters.
However, launch targets for first fight by the Boeing Starliner and SpaceX Crew Dragon have been repeatedly postponed from 2015 to 2018 – in the latest iteration – due to severe and extremely shortsighted funding cutbacks by Congress year after year.
Thus NASA has been forced to order several years more additional Soyuz taxi seat flights and send hundreds and hundreds of millions of more US dollars to Putin’s Russia – thanks to the US Congress.
Congress enjoys whining about Russia on one hand, while at the same time they put America’s aerospace workers on the unemployment line by curtailing NASA’s ability to move forward and put Americans back to work. There is ample bipartisan blame for this sad state of affairs.
The Boeing Starliner and SpaceX Crew Dragon are both Made in America.
The Boeing Starliner is being manufactured at the Kennedy Space Center inside a repurposed and renovated former Space Shuttle Orbiter Processing hangar. This author has visited the C3PF facility periodically to observe and assess Boeing’s progress. The honeycombed upper dome of a Boeing Starliner spacecraft on a work stand inside the company’s Commercial Crew and Cargo Processing Facility at NASA’s Kennedy Space Center in Florida. The upper dome is part of Spacecraft 1 , the first flightworthy Starliner being developed in partnership with NASA’s Commercial Crew Program. Credit: Ken Kremer/kenkremer.com
Indeed, Boeing has already started construction of the first flight worthy Starliner – currently dubbed Spacecraft 1- at KSC this past summer 2016.
Looking inside the newly upgraded Starliner mockup with display panel, astronauts seats, gear and hatch at top that will dock to the new International Docking Adapter (IDA) on the ISS. Credit: Ken Kremer/kenkremer.com
The SpaceX Crew Dragon is being manufactured at company headquarters in Hawthorne, California.
Blastoff of the first SpaceX Crew Dragon spacecraft on its first unmanned test flight, or Demonstration Mission 1, is postponed from May 2017 to November 2017, according to the latest quarterly revision just released by NASA last month in Dec. 2016.
Liftoff of the first piloted Crew Dragon with a pair of NASA astronauts strapped in has slipped from August 2017 to May 2018.
Launch of the first uncrewed Boeing Starliner, known as an Orbital Flight Test, has slipped to June 2018.
Liftoff of the first crewed Starliner is now slated for August 2018, possibly several months after SpaceX. But the schedules keep changing so it’s anyone’s guess as to when these commercial crew launches will actually occur.
Boeing’s uncrewed flight test, known as an Orbital Flight Test, is currently scheduled for June 2018 and its crewed flight test currently is planned for August 2018.
“Once the flight tests are complete and NASA certifies the providers for flight, the post-certification missions to the space station can begin,” NASA official said.
Fiery blastoff of a United Launch Alliance (ULA) Atlas V rocket like this one will launch the Boeing CST-100 Starliner to the ISS. Note the newly installed crew access tower and crew access arm and white room. Here is is carrying the EchoStar XIX satellite from Space Launch Complex-41 on Cape Canaveral Air Force Station, Fl., at 2:13 p.m. EST on Dec. 18, 2016. Credit: Ken Kremer/kenkremer.com
Meanwhile the rockets and launch pads for Boeing and SpaceX are also being developed, modified and refurbished as warranted.
The launch pads for both are located on Florida’s Space Coast.
The SpaceX Crew Dragon will launch on the company’s own Falcon 9 from Launch Pad 39A at NASA’s Kennedy Space Center.
SpaceX is renovating Launch Complex 39A at the Kennedy Space Center for launches of commercial and human rated Falcon 9 rockets as well as the Falcon Heavy, as seen here during Dec 2016 with construction of a dedicated new transporter/erector. Credit: Ken Kremer/kenkremer.com
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
A crane lifts the Crew Access Arm and White Room for Boeing’s CST-100 Starliner spacecraft for mating to the Crew Access Tower at Cape Canaveral Air Force Station’s Space Launch Complex 41 on Aug. 15, 2016. Astronauts will walk through the arm to board the Starliner spacecraft stacked atop a United Launch Alliance Atlas V rocket. Credit: Ken Kremer/kenkremer.com
Composite view of the collision between galaxy clusters Abell 3411 and Abell 3412 . Credit: X-ray: NASA/CXC/SAO/R. van Weeren et al./NAOJ/Subaru
This week, the 229th Meeting of the American Astronomical Society (AAS) kicked off in Grapevine, Texas. Between Monday and Friday (January 3rd to January 7th), attendees will be hearing presentations by researchers and scientists from several different fields as they share the latest discoveries in astronomy and Earth science.
One of the highlights so far this week was a presentation from NASA’s Chandra X-ray Observatory, which took place on the morning of Wednesday, January 5th. In the course of the presentation, an international research team showed some stunning images of two of the most powerful cosmic forces seen together for the first time – a supermassive black hole and two massive galaxy clusters colliding.
The galaxy clusters are known as Abell 3411 and Abell 3412, which are located about two billion light years from Earth. Both of these clusters are quite massive, each possessing the equivalent of about a quadrillion times the mass of our Sun. Needless to say, the collision of these objects produced quite the shockwave, which included the release of hot gas and energetic particles.
X-ray image of the collision between Abell 3411 and Abell 3412. Credit: NASA/CXC/SAO/R. van Weeren et al.
This was made all the more impressive thanks to the presence of a supermassive black hole (SMBH) at the center of one of the galaxy clusters. As the team described in their paper – titled “The Case for Electron Re-Acceleration at Galaxy Cluster Shocks” – the galactic collision produced a nebulous outburst of x-rays (shown above), which were produced when hot clouds of gas from one cluster plowed through the hot gas clouds of the other.
Meanwhile, the inflowing gas was accelerated outward into a jet-like stream, thanks to the powerful electromagnetic fields of the SMBH. These particles were accelerated even further when they got swept up by the shock waves produced by the collision of the galactic clusters and their massive gas clouds. These streams were detected thanks to the burst of radio waves they released as a result.
By seeing these two major events happening at the same time in the same place, the research team effectively witnessed a cosmic “double whammy”. As Felipe Andrade-Santos of the Harvard-Smithsonian Center for Astrophysics (CfA), and co-author of the paper, described it in a Chandra press release:
“It’s almost like launching a rocket into low-Earth orbit and then getting shot out of the Solar System by a second rocket blast. These particles are among the most energetic particles observed in the Universe, thanks to the double injection of energy.”
Image of radio waves produce by the collision between Abell 3411 and Abell 3412. Credit: NASA/CXC/SAO/R. van Weeren et al.
Relying on data obtained from the Chandra X-ray Observatory, the Giant Metrewave Radio Telescope (GMRT) in India, the Karl G. Jansky Very Large Array, the Keck Observatory, and Japan’s Subaru Telescope, the team was able to capture this event in the optical, x-ray, and radio wave wavelengths. This not only led to some stunning images, but shed some light on a long-standing mystery in galaxy research.
In the past, astronomers have detected radio emissions coming from Abell 3411 and Abell 3412 using the GMRT. But the origins of these emissions, which reached for millions of light years, was the subject of speculation and debate. Relying on the data they obtained, the research team was able to determine that they are the result of energetic particles (produced by the clouds of hot gas colliding) being further accelerated by galactic shock waves.
Or as co-author William Dawson, of the Lawrence Livermore National Lab in Livermore, California, put it:
“This result shows that a remarkable combination of powerful events generate these particle acceleration factories, which are the largest and most powerful in the Universe. It is a bit poetic that it took a combination of the world’s biggest observatories to understand this.”
Many interesting finds have been shared since the 229th Meeting of the AAS began – like the hunt for the source of a Fast Radio Burst – and many more are expected before it wraps up at the end of the week. These will include the latest results from the Sloan Digital Sky Survey (SDSS), and new and exciting research on black holes, exoplanets, and other astronomical phenomena.
And be sure to check out this podcast from Chandra as well, which talks about the collision between Abell 3411 and 3412 and the cosmic forces it unleashed.
An artist’s conception of the Lucy spacecraft (left) flying by the Trojan Eurybates, and Psyche (Right) Psyche, the first mission to the metal world 16 Psyche.
Credits: SwRI and SSL/Peter Rubin
It’s a New Year, with new challenges and new opportunities! And NASA, looking to kick things off, has announced the two new missions that will be launching in the coming decade. These robotic missions, named Lucy and Psyche, are intended to help us understand the history of the early Solar System, and will deploy starting in 2021 and 2023, respectively.
While Lucy’s mission is to explore one of Jupiter’s Trojan asteroids, Psyche will explore a metal asteroid known as 16 Psyche. And between the two of them, it is hoped that they will answer some enduring questions about planetary formation and how the Solar System came to be. More than that, these mission represent historic firsts for NASA and human space exploration.
NASA’s Discovery Program, of which Lucy and Psyche are part, was created in 1992 to compliment their larger “flagship” programs. By bringing scientists and engineers together to design missions, the Discovery Program’s focus has been to maximize scientific research by creating many smaller missions that have shorter development periods and require less in the way of operational resources.
Artist’s concept of the Lucy spacecraft flying by Eurybates, one of the six diverse and scientifically important Trojans it will study. Credit: SwRI
The Lucy mission is scheduled to launch in October of 2021, and is expected to arrive at its first destination (a Main Belt asteroid) in 2025. It will then set course for Jupiter’s Trojans, a group of asteroids that are trapped by Jupiter’s gravity and share its orbit. These asteroids are thought to be relics of the early Solar System; and between 2027 and 2033, Lucy will study six of them.
In addition to being the first mission to explore Jupiter’s Trojan population, Lucy is also of historic importance because of the number of asteroids it will visit. Throughout the course of its mission, it is will investigate six Trojans, which is the total number of Main Belt asteroids that have been studied to date. The nature of these six asteroids is also expected to tell us much about the early history of the Solar System.
As Harold F. Levison – the principal investigator of the Lucy mission from the Southwest Research Institute (SwRI) in Boulder, Colorado – explained during a NASA call-in briefing:
“One of the surprising aspects of this population is their diversity. If we look at them through telescopes on the Earth, we see that they are very different from one other in their color, in their spectra. And so, we believe that’s telling us something about how the Solar System formed and evolved… This diversity in these objects, we believe, are due to the fact that they actually formed in very different regions of the Solar System, with very different physical characteristics. And something occurred in the history of the Solar System where these objects started off at very different distances, but during the formation and evolution of the Solar System, they got moved around and placed in these stable reservoirs near Jupiter’s orbit.”
Illustration of the Lucy spacecraft’s orbit around Jupiter, which will allow it to study its Trojan population. Credit: SwRI
The six Trojans that Lucy is intended investigate were selected because the diversity of their physical characteristics show that they are from different locations throughout the Solar System. As Levison put it, “These small bodies really are the fossils of planet formation, and that’s why we named Lucy after the human ancestor known as Lucy.”
In addition, Lucy will build on the success of missions like New Horizons and OSIRIS-REx., which includes using updated versions of instruments they used to explore Pluto, the Kuiper Belt, and the asteroid Bennu -i.e. the RALPH and LORRI instruments and the OTES instrument. In addition, several members of the New Horizons and OSIRIS-REx science teams will be lending their expertise to the Lucy mission.
Similarly, the Psyche mission will of be immense scientific value since it will visit the only metal asteroid known to exist. This asteroid measures about 210 km (130 mi) in diameter and is believed to be composed entirely of iron and nickel. In this respect, it is similar to Earth’s metallic core, as well as the cores of every terrestrial planet in the Solar System.
It is for this reason why scientists believe it may be the exposed core of a Mars-sized planet. According to this theory, 16 Psyche experienced several major collisions during the early history of the Solar System, which caused it to shed its rocky mantle. The robotic probe will launch in 2023 and is expected to arrive by 2030 – after receiving an Earth gravity-assist maneuver in 2024 and a Mars flyby in 2025.
By measuring its composition, magnetic field, and mapping its surface features, Lucy’s science team hopes to learn more about the history of planetary formation. As Lindy Elkins-Tanton – the Principal Investigator of Psyche and the Director of the School of Earth and Space Exploration at Arizona State University – said during the NASA call-in briefing:
“Humankind has visited rocky worlds and icy worlds and worlds made of gas. But we have never seen a metal world. Psyche has never been visited or had a picture taken that was more than a point of light. And so, its appearance remains a mystery. This mission will be true exploration and discovery. We think that Psyche is the metal core of a small planet that was destroyed in the high-energy, high-speed, first one-one-hundredth of the age of our Solar System. By visiting Psyche we can literally visit a planetary core the only way humanity can… Psyche let’s us visit inner space by visiting outer space.”
Not only are planetary cores thought to be where magnetic fields originate (which are necessary for the emergence of life), but they are entirely inaccessible to us. The very edge of Earth’s outer core is roughly 2,890 km (1790 mi) from our planet’s surface. But the deepest humanity has ever dug has been to a depth of 12 km (7.5 mi), which took place at the Kola Superdeep Borehole, in Russia.
In addition, within the Earth’s core, temperature and pressure conditions are estimated to reach 5700 K (5400 °C; 9752 °F) and 330 to 360 gigapascals (over three million times normal air pressure). This makes exploring the core of our planet (or any other planet in the Solar System, for that matter) completely impractical. Hence why a robotic mission to a world like Pysche is such an opportunity.
And since Psyche is the only rounded body of metal that is known to exist in the Solar System, the asteroid is as improbably as it is unique. And since no missions have ever taken place to explore its surface, and no pictures exist that can tell us what its surface features would look like, the Psyche mission is sure to shed some serious light on what a metal world looks like.
“What do we think it might look like?” asked Tanton. “Does it have surface sulfur lava flows on its surface? Is it covered with towering cliffs created when solidifying metal shrank and the exterior of the body broke into fault? Is its surface a combination of iron metal and green mineral crystal as iron meteorites are? And what does an impact crater in metal look like? Could its edges or its metal flashes become frozen in the cold of space before they fell back on the surface. We don’t know.”
Jim Green, NASA’s Planetary Science Director, expressed enthusiasm for the Discovery 13 and 14 missions in a recent NASA press release:
“These are true missions of discovery that integrate into NASA’s larger strategy of investigating how the solar system formed and evolved. We’ve explored terrestrial planets, gas giants, and a range of other bodies orbiting the sun. Lucy will observe primitive remnants from farther out in the solar system, while Psyche will directly observe the interior of a planetary body. These additional pieces of the puzzle will help us understand how the sun and its family of planets formed, changed over time, and became places where life could develop and be sustained – and what the future may hold.”
Lucy and Psyche were chosen from five finalists that were selected for further development back in September 2015. These in turn were chosen from 27 mission concepts that were submitted back in November of 2014. Examples of past and present Discovery missions include the Kepler space probe, the Dawn spacecraft, the Mars Pathfinder, and the InSight lander (which is scheduled to launch in 2018).
Gemini composite image of the field around FRB 121102, the only repeating FRB discovered so far. Credit: Gemini Observatory/AURA/NSF/NRC.
For about 10 years, radio astronomers have been detecting mysterious milliseconds-long blasts of radio waves, called “fast radio bursts” (FRB).
While only 18 of these events have been detected so far, one FRB has been particularly intriguing as the signal has been sporadically repeating. First detected in November 2012, astronomers didn’t know if FRB 121102 originated from within the Milky Way galaxy or from across the Universe.
A concentrated search by multiple observatories around the world has now determined that the signals are coming from a dim dwarf galaxy about 2.5 billion light years from Earth. But astronomers are still uncertain about exactly what is creating these bursts.
“These radio flashes must have enormous amounts of energy to be visible from that distance,” said Shami Chatterjee from Cornell University, speaking at a press briefing at the American Astronomical Society meeting this week. Chatterjee and his colleagues have papers published today in Nature and Astrophysical Journal Letters.
The globally distributed dishes of the European VLBI Network are linked with each other and the 305-m William E. Gordon Telescope at the Arecibo Observatory in Puerto Rico. Credit:?Danielle?Futselaar.
The patch of the sky where the signal originated is in the constellation Auriga, and Chatterjee said the patch of the sky is arc minutes in diameter. “In that patch are hundreds of sources. Lots of stars, lots of galaxies, lots of stuff,” he said, which made the search difficult.
The Arecibo radio telescope, the observatory that originally detected the event, has a resolution of three arc minutes or about one-tenth of the moon’s diameter, so that was not precise enough to identify the source. Astronomers used the Very Large Array in New Mexico and the European Very Large Baseline Interferometer (VLBI) network, to help narrow the origin. But, said co-author Casey Law from the University of California Berkeley, that also created a lot of data to sort through.
“It was like trying to find a needle in a terabyte haystack,” he said. “It took a lot of algorithmic work to find it.”
Finally on August 23, 2016, the burst made itself extremely apparent with nine extremely bright bursts.
“We had struggled to be able to observe the faintest bursts we could,” Law said, “but suddenly here were nine of the brightest ones ever detected. This FRB was generous to us.”
The team was not only able to pinpoint it to the distant dwarf galaxy, co-author Jason Hessels from ASTRON/University of Amsterdam said they were also able to determine the bursts didn’t come from the center of the galaxy, but came from slightly off-center in the galaxy. That might indicate it didn’t originate from a central black hole. Upcoming observations with the Hubble Space Telescope might be able to pinpoint it even further.
Gemini composite image of the field around FRB 121102 (indicated). The dwarf host galaxy was imaged, and spectroscopy performed, using the Gemini Multi-Object Spectrograph (GMOS) on the Gemini North telescope on Maunakea in Hawai’i. Data was obtained on October 24-25 and November 2, 2016. Credit: Gemini Observatory/AURA/NSF/NRC.
What makes this source burst repeatedly?
“We don’t know yet what caused it or the physical mechanism that makes such bright and fast pulses,” said said Sarah Burke-Spolaor, from West Virginia University. “The FRB could be outflow from an active galactic nuclei (AGN) or it might be more familiar, such as a distant supernova remnant, or a neutron star.”
Burke-Spolaor added that they don’t know yet if all FRBs are created equal, as so far FRB 121102 is the only repeater. The team hopes there will be other examples detected.
“It may be a magnetar – a newborn neutron star with a huge magnetic field, inside a supernova remnant or a pulsar wind nebula – somehow producing these prodigious pulses,” said Chatterjee. “Or, it may be a combination of all these ideas – explaining why what we’re seeing may be somewhat rare.”
Image showing nearly 50,000 galaxies in the nearby universe detected by the Two Micron All Sky Survey (2MASS) in infrared light. Credit: 2MASS/ T. H. Jarrett/J. Carpenter/R. Hurt
Scientists have known for some time that the Milky Way Galaxy is not alone in the Universe. In addition to our galaxy being part of the Local Group – a collection of 54 galaxies and dwarf galaxies – we are also part of the larger formation known as the Virgo Supercluster. So you could say the Milky Way has a lot of neighbors.
Of these, most people consider the Andromeda Galaxy to be our closest galactic cohabitant. But in truth, Andromeda is the closest spiral galaxy, and not the closest galaxy by a long shot. This distinction falls to a formation that is actually within the Milky Way itself, a dwarf galaxy that we’ve only known about for a little over a decade.
Closest Galaxy:
At present, the closet known galaxy to the Milky Way is the Canis Major Dwarf Galaxy – aka. the Canis Major Overdensity. This stellar formation is about 42,000 light years from the galactic center, and a mere 25,000 light years from our Solar System. This puts it closer to us than the center of our own galaxy, which is 30,000 light years away from the Solar System.
Illustration of the Canis Dwarf Galaxy and its associated tidal (shown in red) in relation to our Milky Way. Credit: R. Ibata (Strasbourg Observatory, ULP) et al./2MASS/NASA
Characteristics:
The Canis Major Dwarf Galaxy Dwarf Galaxy is believed to contain one billion stars in all, a relatively high-percentage of which are in the Red Giant Branch phase of their lifetimes. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy, the previous contender for closest galaxy to our location in the Milky Way.
In addition to the dwarf galaxy itself, a long filament of stars is visible trailing behind it. This complex, ringlike structure – which is sometimes referred to as the Monoceros Ring – wraps around the galaxy three times. The stream was first discovered in the early 21st century by astronomers conducting the Sloan Digital Sky Survey (SDSS).
It was in the course of investigating this ring of stars, and a closely spaced group of globular clusters similar to those associated with the Sagittarius Dwarf Elliptical Galaxy, that the Canis Major Dwarf Galaxy was first discovered. The current theory is that this galaxy was accreted (or swallowed up) by the Milky Way Galaxy.
Other globular clusters that orbit the center of our Milky Way as a satellite – i.e. NGC 1851, NGC 1904, NGC 2298 and NGC 2808 – are thought to have been part of the Canis Major Dwarf Galaxy before its accretion. It also has associated open clusters, which are thought to have formed as a result of the dwarf galaxy’s gravity perturbing material in the galactic disk and stimulating star formation.
Images of a few examples of merging galaxies taken by the Hubble Space Telescope. Credit: NASA/ESA/STScI/A. Evans/NRAO/Caltech
Discovery:
Prior to its discovery, astronomers believed that the Sagittarius Dwarf Galaxy was the closest galactic formation to our own. At 70,000 light years from Earth, this galaxy was determined in 1994 to be closer to us than the Large Magellanic Cloud (LMC), the irregular dwarf galaxy that is located 180,000 light years from Earth, and which previously held the title of the closest galaxy to the Milky Way.
All of that changed in 2003 when The Canis Major Dwarf Galaxy was discovered by the Two Micron All-Sky Survey (2MASS). This collaborative astronomical mission, which took place between 1997 and 2001, relied on data obtained by the Mt. Hopkins Observatory in Arizona (for the Northern Hemisphere) and the Cerro Tololo Inter-American Observatory in Chile (for the southern hemisphere).
From this data, astronomers were able to conduct a survey of 70% of the sky, detecting about 5,700 celestial sources of infrared radiation. Infrared astronomy takes advantage of advances in astronomy that see more of the Universe, since infrared light is not blocked by gas and dust to the same extent as visible light.
Because of this technique, the astronomers were able to detect a very significant over-density of class M giant stars in a part of the sky occupied by the Canis Major constellation, along with several other related structures composed of this type of star, two of which form broad, faint arcs (as seen in the image close to the top).
An artist depicts the incredibly powerful flare that erupted from the red dwarf star EV Lacertae. Credit: Casey Reed/NASA
The prevalence of M-class stars is what made the formation easy to detect. These cool, “Red Dwarfs” are not very luminous compared to other classes of stars, and cannot even be seen with the naked eye. However, they shine very brightly in the infrared, and appeared in great numbers.
The discovery of this galaxy, and subsequent analysis of the stars associated with it, has provided some support for the current theory that galaxies may grow in size by swallowing their smaller neighbors. The Milky Way became the size it is now by eating up other galaxies like Canis Major, and it continues to do so today. And since stars from the Canis Major Dwarf Galaxy are technically already part of the Milky Way, it is by definition the nearest galaxy to us.
As already noted, it was the Sagittarius Dwarf Elliptical Galaxy that held the position of closest galaxy to our own prior to 2003. At 75,000 light years away. This dwarf galaxy, which consists of four globular clusters that measure some 10,000 light-years in diameter, was discovered in 1994. Prior to that, the Large Magellanic Cloud was thought to be our closest neighbor.
The Andromeda Galaxy (M31) is the closest spiral galaxy to us, and though it’s gravitationally bound to the Milky Way, it’s not the closest galaxy by far – being 2 million light years away. Andromeda is currently approaching our galaxy at a speed of about 110 kilometers per second. In roughly 4 billion years, the Andromeda Galaxy is expected to merge with out own, forming a single, super-galaxy.
Future of the Canis Major Dwarf Galaxy:
Astronomers also believe that the Canis Major Dwarf Galaxy is in the process of being pulled apart by the gravitational field of the more massive Milky Way Galaxy. The main body of the galaxy is already extremely degraded, a process which will continue as it travels around and through our Galaxy.
In time, the accretion process will likely culminate with the Canis Major Dwarf Galaxy merging entirely with the Milky Way, thus depositing its 1 billion stars to the 200 t0 400 billion that are already part of our galaxy.
For more information, check out this article from the Spitzer Space Telescope‘s website about the galaxies that are closest to the Milky Way Galaxy. And here is a video by the same author on the subject.
Artist's impression of ice age Earth at glacial maximum. Credit: Wikipedia Commons/Ittiz
Scientists have known for some time that the Earth goes through cycles of climatic change. Owing to changes in Earth’s orbit, geological factors, and/or changes in Solar output, Earth occasionally experiences significant reductions in its surface and atmospheric temperatures. This results in long-term periods of glaciation, or what is more colloquially known as an “ice age”.
These periods are characterized by the growth and expansion of ice sheets across the Earth’s surface, which occurs every few million years. By definition we are still in the last great ice age – which began during the late Pliocene epoch (ca. 2.58 million years ago) – and are currently in an interglacial period, characterized by the retreat of glaciers.
Definition:
While the term “ice age” is sometime used liberally to refer to cold periods in Earth’s history, this tends to belie the complexity of glacial periods. The most accurate definition would be that ice ages are periods when ice sheets and glaciers expand across the planet, which correspond to significant drops in global temperatures and can last for millions of years.
The Antarctic ice sheet, which expanded during the last ice age. Credit: Wikipedia Commons/Stephen Hudson
During an ice age, there are significant temperature differences between the equator and the poles, and temperatures at deep-sea levels have also been shown to drop. This allows for large glaciers (comparable to continents) to expand, covering much of the surface area of the planet. Since the Pre-Cambrian Era (ca. 600 million years ago), ice ages have occurred at widely space intervals about about 200 million years.
History of Study:
The first scientist to theorize about past glacial periods was the 18th century Swiss engineer and geographer Pierre Martel. In 1742, while visiting an Alpine valley, he wrote about the dispersal of large rocks in erratic formations, which the locals attributed to the glaciers having once extended much further. Similar explanations began to emerge in the ensuing decades for similar patterns of boulder distribution in other parts of he world.
From the middle of the 18th century onward, European scholars increasingly began to contemplate ice as a means of transporting rocky material. This included the presence of boulders in coastal areas in the Baltic states and the Scandinavian peninsula. However, it was Danish-Norwegian geologist Jens Esmark (1762–1839) who first argued the existence of a sequence of world wide ice ages.
This theory was detailed in a paper he published in 1824, in which he proposed that changes in Earth’s climate (which were due to changes in its orbit) were responsible. This was followed in 1832 by German geologist and forestry professor Albrecht Reinhard Bernhardi speculating about how the polar ice caps may have once reached as far as the temperate zones of the world.
Overlook of the Grinnell Glacier in Glacier National Park, Montana. Credit: USGS
At this same time, German botanist Karl Friedrich Schimper and Swiss-American biologist Louis Agassiz began independently developing their own theory about global glaciation, which led toSchimper coining the term “ice age” in 1837. By the late 19th century, ice age theory gradually began to gain widespread acceptance over the notion that the Earth cooled gradually from its original, molten state.
By the 20th century, Serbian polymath Milutin Milankovic developed his concept of Milankovic cycles, which linked long-term climate changes to periodic changes in the Earth’s orbit around the Sun. This offered a demonstrable explanation for ice ages, and allowed scientists to make predictions about when significant changes in Earth’s climate might occur again.
Evidence for Ice Ages:
There are three forms of evidence for ice age theory, which range from the geological and the chemical to the paleontological (i.e. the fossil record). Each has its particular benefits and drawbacks, and has helped scientists to develop a general understanding of the effect ice ages have had on geological record for the past few billion years.
Geological: Geological evidence includes rock scouring and scratching, carved valleys, the formation of peculiar types of ridges, and the deposition of unconsolidated material (moraines) and large rocks in erratic formations. While this sort of evidence is what led to ice age theory in the first place, it remains temperamental.
For one, successive glaciation periods have different effects on a region, which tends to distort or erase geological evidence over time. In addition, geological evidence is difficult to date exactly, causing problems when it comes to getting an accurate assessment of how long glacial and interglacial periods have lasted.
Horseshoe-shaped lateral moraines at the margin of the Penny Ice Cap on Baffin Island, Nunavut, Canada. Lateral moraines are accumulations of debris along the sides of a glacier formed by material falling from the valley wall. Credit: NASA/Michael Studinger
Chemical: This consists largely of variations in the ratios of isotopes in fossils discovered in sediment and rock samples. For more recent glacial periods, ice cores are used to construct a global temperature record, largely from the presence of heavier isotopes (which lead to higher evaporation temperatures). They often contain bubbles of air as well, which are examined to assess the composition of the atmosphere at the time.
Limitations arise from various factors, however. Foremost among these are isotope ratios, which can have a confounding effect on accurate dating. But as far as the most recent glacial and interglacial periods are concerned (i.e. during the past few million years), ice core and ocean sediment core samples remain the most trusted form of evidence.
Paleontological: This evidence consists of changes in the geographical distribution of fossils. Basically, organisms that thrive in warmer conditions become extinct during glacial periods (or become highly restricted in lower latitudes), while cold-adapted organisms thrive in these same latitudes. Ergo, reduced amounts of fossils in higher latitudes is an indication of the spread of glacial ice sheets.
This evidence can also be difficult to interpret because it requires that the fossils be relevant to the geological period under study. It also requires that sediments over wide ranges of latitudes and long periods of time show a distinct correlation (due to changes in the Earth’s crust over time). In addition, there are many ancient organisms that have shown the ability to survive changes in conditions for millions of years.
As a result, scientists rely on a combined approach and multiple lines of evidence wherever possible.
Ice ages are characterized by a drop in average global temperatures, resulting in the expansion of ice sheets globally. Credit: NASA
Causes of Ice Ages:
The scientific consensus is that several factors contribute to the onset of ice ages. These include changes in Earth’s orbit around the Sun, the motion of tectonic plates, variations in Solar output, changes in atmospheric composition, volcanic activity, and even the impact of large meteorites. Many of these are interrelated, and the exact role that each play is subject to debate.
Earth’s Orbit: Essentially, Earth’s orbit around the Sun is subject to cyclic variations over time, a phenomenon also known as Milankovic (or Milankovitch) cycles. These are characterized by changing distances from the Sun, the precession of the Earth’s axis, and the changing tilt of the Earth’s axis – all of which result in a redistribution of the sunlight received by the Earth.
The most compelling evidence for Milankovic orbital forcing corresponds closely to the most recent (and studied) period in Earth’s history (circa. during the last 400,000 years). During this period, the timing of glacial and interglacial periods are so close to changes in Milankovic orbital forcing periods that it is the most widely accepted explanation for the last ice age.
Tectonic Plates: The geological record shows an apparent correlation between the onset of ice ages and the positions of the Earth’s continents. During these periods, they were in positions which disrupted or blocked the flow of warm water to the poles, thus allowing ice sheets to form.
The Earth’s Tectonic Plates. Credit: msnucleus.org
This in turn increased the Earth’s albedo, which reduces the amount of solar energy absorbed by the Earth’s atmosphere and crust. This resulted in a positive feedback loop, where the advance of ice sheets further increased the Earth’s albedo and allowed for more cooling and more glaciation. This would continue until the onset of a greenhouse effect ended the period of glaciation.
Based on past ice-ages, three configurations have been identified that could lead to an ice age – a continent sitting atop the Earth’s pole (as Antarctica does today); a polar sea being land-locked (as the Arctic Ocean is today); and a super continent covering most of the equator (as Rodinia did during the Cryogenian period).
In addition, some scientists believe that the Himalayan mountain chain – which formed 70 million years ago – has played a major role in the most recent ice age. By increasing the Earth’s total rainfall, it has also increased the rate at which CO² has been removed from the atmosphere (thereby decreasing the greenhouse effect). Its existence has also paralleled the long-term decrease in Earth’s average temperature over the past 40 million years.
Atmospheric Composition: There is evidence that levels of greenhouse gases fall with the advance of ice sheets and rise with their retreat. According to the “Snowball Earth” hypothesis – in which ice completely or very nearly covered the planet at least once in the past – the ice age of the late Proterozoic was ended by an increase in CO² levels in the atmosphere, which was attributed to volcanic eruptions.
Image of the Harding Ice Field on Alaska’s Kenai Peninsula. Credit: US Fish and Wildlife Service
However, there are those who suggest that increased levels of carbon dioxide may have served as a feedback mechanism, rather than the cause. For example, in 2009, an international team of scientists produced a study – titled “The Last Glacial Maximum” – that indicated that an increase in solar irradiance (i.e. energy absorbed from the Sun) provided the initial change, whereas greenhouse gases accounted for the magnitude of change.
Major Ice Ages:
Scientists have determined that at least five major ice ages took place in Earth’s history. These include the Huronian, Cryogenian, Andean-Saharan, Karoo, and the Qauternary ice ages. The Huronian Ice Age is dated to the early Protzerozoic Eon, roughly 2.4 to 2.1 billion years ago, based on geological evidence observed to the north and north-east of Lake Huron (and correlated to deposits found in Michigan and Western Australia).
The Cryogenian Ice Age lasted from roughly 850 to 630 million years ago, and was perhaps the most severe in Earth’s history. It is believed that during this period, the glacial ice sheets reached the equator, thus leading to a “Snowball Earth” scenario. It is also believed that ended due to a sudden increase in volcanic activity that triggered a greenhouse effect, though (as noted) this is subject to debate.
The Andean-Saharan Ice Age occurred during the Late Ordovician and the Silurian period (roughly 460 to 420 million years ago). As the name suggests, the evidence here is based on geological samples take from the Tassili n’Ajjer mountain range in the western Sahara, and correlated by evidence obtained from the Andean mountain chain in South America (as well as the Arabian peninsula and the south Amazon basin).
Floating ice at the calving front of Greenland’s Kangerdlugssuaq glacier, photographed in 2011 during Operation IceBridge. Credit: NASA/Michael Studinger
The Karoo Ice Age is attributed to the evolution of land plants during the onset of the Devonian period (ca. 360 to 260 million years ago) which caused a long-term increase in planetary oxygen levels and a reduction in CO² levels – leading to global cooling. It is named after sedimentary deposits that were discovered in the Karoo region of South Africa, with correlating evidence found in Argentina.
The current ice age, known as the Pliocene-Quaternary glaciation, started about 2.58 million years ago during the late Pliocene, when the spread of ice sheets in the Northern Hemisphere began. Since then, the world has experienced several glacial and interglacial periods, where ice sheets advance and retreat on time scales of 40,000 to 100,000 years.
The Earth is currently in an interglacial period, and the last glacial period ended about 10,000 years ago. What remains of the continental ice sheets that once stretched across the globe are now restricted to Greenland and Antarctic, as well as smaller glaciers – like the one that covers Baffin Island.
Anthropogenic Climate Change:
The exact role played by all the mechanisms that ice ages are attributed to – i.e. orbital forcing, solar forcing, geological and volcanic activity – are not yet entirely understood. However, given the role of carbon dioxide and other greenhouse gas emissions, there has been a great deal of concern in recent decades what long-term effects human activity will have on the planet.
For instance, in at least two major ice ages, the Cryogenian and Karoo Ice Ages, increases and decreases in atmospheric greenhouse gases are believed to have played a major role. In all other cases, where orbital forcing is believed to be the primary cause of an ice age ending, increased greenhouse gas emissions were still responsible for the negative feedback that led to even greater increases in temperature.
The addition of CO2 by human activity has also played a direct role in climatic changes taking place around the world. Currently, the burning of fossil fuels by humans constitutes the largest source of emissions of carbon dioxide (about 90%) worldwide, which is one of the main greenhouse gases that allows radiative forcing (aka. the Greenhouse Effect) to take place.
In 2013, the National Oceanic and Atmospheric Administration announced that CO² levels in the upper atmosphere reached 400 parts per million (ppm) for the first time since measurements began in the 19th century. Based on the current rate at which emissions are growing, NASA estimates that carbon levels could reach between 550 to 800 ppm in the coming century.
If the former scenario is the case, NASA anticipates a rise of 2.5 °C (4.5 °F) in average global temperatures, which would be sustainable. However, should the latter scenario prove to be the case, global temperatures will rise by an average of 4.5 °C (8 °F), which would make life untenable for many parts of the planet. For this reason, alternatives are being sought out for development and widespread commercial adoption.
What’s more, according to a 2012 research study published in Nature Geoscience – titled “Determining the natural length of the current interglacial” – human emissions of CO² are also expected to defer the next ice age. Using data on Earth’s orbit to calculate the length of interglacial periods, the research team concluded that the next ice (expected in 1500 years) would require atmospheric CO² levels to remain beneath around 240?ppm.
Learning more about the longer ice ages as well the shorter glacial periods that have taken place in Earth’s past is important step towards understanding how Earth’s climate changes over time. This is especially important as scientists seek to determine how much of modern climate change is man-made, and what possible counter-measures can be developed.
Once again, science fiction television and movies has let you down. They try to recreate what it might be like on an alien world, but surprise surprise, they mostly get it wrong. That’s because a truly alien world would be different in so many ways, it would blow your mind. Today we’ll help you figure out if you’re on a movie set, or you’ve actually crashlanded on an alien planet.
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Upgraded SpaceX Falcon 9 blasts off with Thaicom-8 communications satellite on May 27, 2016 from Space Launch Complex 40 at Cape Canaveral Air Force Station, FL. 1st stage booster landed safely at sea minutes later. Credit: Ken Kremer/kenkremer.com
Upgraded SpaceX Falcon 9 blasts off with Thaicom-8 communications satellite on May 27, 2016 from Space Launch Complex 40 at Cape Canaveral Air Force Station, FL. 1st stage booster landed safely at sea minutes later. Credit: Ken Kremer/kenkremer.com
“Targeting return to flight from Vandenberg with the @IridiumComm NEXT launch on January 8,” SpaceX announced on their website today, Monday, Jan. 2., 2017.
“Our date is now public. Next Sunday morning, Jan 8 at 10:28:07 pst. Iridium NEXT launch #1 flies!” Iridium Communications CEO Matt Desch quickly confirmed by tweet today, Jan 2.
SpaceX has been dealing with the far reaching and world famous fallout from the catastrophic launch pad explosion that eviscerated a Falcon 9 and its expensive $200 million Israeli Amos-6 commercial payload in Florida without warning, during a routine preflight fueling test on Sept. 1, 2016, at pad 40 on Cape Canaveral Air Force Station.
The first ten IridiumNEXT satellites are stacked and encapsulated in the Falcon 9 fairing for launch from Vandenberg Air Force Base, Ca., in early 2017. Credit: Iridium
After the Sept. 1 accident at pad 40, SpaceX initiated a joint investigation to determine the root cause with the FAA, NASA, the US Air Force and industry experts who have been “working methodically through an extensive fault tree to investigate all plausible causes.”
“We have been working closely with NASA, and the FAA [Federal Aviation Administration] and our commercial customers to understand it,” said SpaceX CEO Elon Musk.
Via the “fault tree analysis” the Sept. 1 anomaly has been traced to a failure in one of three gaseous helium storage tanks located inside the second stage liquid oxygen (LOX) tank of the Falcon 9 rocket, according to a statement released by SpaceX today which provided some but not many technical details.
The failure apparently originated at a point where the helium tank “buckles” and accumulates oxygen – “leading to ignition” of the highly flammable liquid oxygen propellant in the second stage.
SpaceX Falcon 9 rocket moments after catastrophic explosion destroys the rocket and Amos-6 Israeli satellite payload at launch pad 40 at Cape Canaveral Air Force Station, FL, on Sept. 1, 2016. A static hot fire test was planned ahead of scheduled launch on Sept. 3, 2016. Credit: USLaunchReport
The helium tanks – also known as composite overwrapped pressure vessels (COPVs) – are used in both stages of the Falcon 9 to store cold helium which is used to maintain tank pressure.
“The accident investigation team worked systematically through an extensive fault tree analysis and concluded that one of the three composite overwrapped pressure vessels (COPVs) inside the second stage liquid oxygen (LOX) tank failed.”
“Each COPV consists of an aluminum inner liner with a carbon overwrap.”
“Specifically, the investigation team concluded the failure was likely due to the accumulation of oxygen between the COPV liner and overwrap in a void or a buckle in the liner, leading to ignition and the subsequent failure of the COPV.”
SpaceX says investigators identified “an accumulation of super chilled LOX or SOX in buckles under the overwrap” as “credible causes for the COPV failure.”
Apparently the super chilled LOX or SOX can pool in the buckles and react with carbon fibers in the overwrap – which act as an ignition source.
As part of the most recent upgrade to the Falcon 9, SpaceX changed their fueling procedure to include the use of densified oxygen – or super chilled oxygen – in order to load more propellant into the same volume, at a lower temperature of about minus 340 degrees Fahrenheit for SOX vs. about minus 298 degrees Fahrenheit for LOX.
In essence SpaceX gets more gallons of super chilled oxygen into the same tank volume because of the higher density – and they don’t have to change the rocket’s dimensions.
This temperature change enables the Falcon 9 to launch heavier payloads.
However the side effect of the superchilling process is that the oxygen is now very close to its freezing point – with the potential to partially solidify , rather than being a completely free flowing liquid. Then the resulting friction with carbon fibers can ignite the pooled oxygen resulting in an instantaneous fireball and destruction of the rocket – as happened to Falcon 9 and Amos-6 at pad 40 on Sept. 1, 2016.
“Investigators concluded that super chilled LOX can pool in these buckles under the overwrap. When pressurized, oxygen pooled in this buckle can become trapped; in turn, breaking fibers or friction can ignite the oxygen in the overwrap, causing the COPV to fail.”
Very concerning to this author is the fact that the helium loading conditions are confirmed to be so low that they can actually freeze the liquid oxygen into solid form. Thus it cannot flow freely and significantly increases the chances of a “friction ignition.”
This same Falcon 9 rocket will be used to launch our astronauts to the ISS in 2018 – seated inside a Crew Dragon atop the helium tank bathed in super chilled LOX.
“Investigators determined that the loading temperature of the helium was cold enough to create solid oxygen (SOX), which exacerbates the possibility of oxygen becoming trapped as well as the likelihood of friction ignition.”
SpaceX says they will address the causes of the mishap through a mix of both short term and long term “corrective actions.”
“The corrective actions address all credible causes and focus on changes which avoid the conditions that led to these credible causes.”
The short term fixes involve simpler changes to the COPV configuration and modifying the helium loading conditions.
“In the short term, this entails changing the COPV configuration to allow warmer temperature helium to be loaded, as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads.”
So it remains to be seen if SpaceX continues the use of densified oxygen or not in the near term.
The long term fixes involve changing the COPV hardware itself and will take longer to implement. They are also likely to be more effective – but only time will tell.
“In the long term, SpaceX will implement design changes to the COPVs to prevent buckles altogether, which will allow for faster loading operations.”
Liftoff of the SpaceX Falcon 9 with the payload of 10 identical next generation IridiumNEXT communications satellites will take place from Space Launch Complex 4E on Vandenberg Air Force Base in California – assuming the required approval is first granted by the Federal Aviation Administration (FAA).
No Falcon 9 launch will occur until the FAA gives the ‘GO.’
Furthermore, in anticipation of announcing the targeted ‘Return to Flight’ launch date, technicians have already processed the Falcon 9 rocket for the ‘Return to Flight’ blastoff with the vanguard of a fleet of IridiumNEXT mobile voice and data relay satellites for Iridium Communications – as I reported last week in my story here – and subsequently tweeted by Iridium CEO Matt Desch saying “Nice recap.”
IridiumNEXT satellites being fueled, pressurized & stacked on dispenser tiers at Vandenberg AFB for Falcon 9 launch. Credit: Iridium
Last week, the first ten IridiumNEXT mobile voice and data relay satellites were fueled, stacked and tucked inside the nose cone of the Falcon 9 rocket designated as SpaceX’s ‘Return to Flight’ launcher in order to enable a blastoff as soon as possible after an approval is received from the FAA.
“Iridium is pleased with SpaceX’s announcement on the results of the September 1 anomaly as identified by their accident investigation team, and their plans to target a return to flight on January 8 with the first Iridium NEXT launch” Iridium Communications said on their website today, Jan. 2.
Another milestone to watch for is the first stage engine static fire test that SpaceX routinely conducts several days prior to the launch. Thats exactly the same type test where the Falcon 9 blew up in Florida some five minutes before the short Merlin 1D engine ignition to confirm readiness for the real launch that had been planned for 2 days later.
Iridium’s SpaceX Falcon9 rocket in processing at Vandenberg Air Force Base, getting ready for launch in early Jan. 2017. Credit: Iridium
The Iridium 1 mission is the first of seven planned Falcon 9 launches – totaling 70 satellites.
“Iridium is replacing its existing constellation by sending 70 Iridium NEXT satellites into space on a SpaceX Falcon 9 rocket over 7 different launches,” says Iridium.
The goal of this privately contracted mission is to deliver the first 10 Iridium NEXT satellites into low-earth orbit to inaugurate what will be a new constellation of satellites dedicated to mobile voice and data communications.
Iridium eventually plans to launch a constellation of 81 Iridium NEXT satellites into low-earth orbit.
“At least 70 of which will be launched by SpaceX,” per Iridium’s contract with SpaceX.
SpaceX is renovating Launch Complex 39A at the Kennedy Space Center for launches of commercial and human rated Falcon 9 rockets as well as the Falcon Heavy, as seen here during Dec 2016 with construction of a dedicated new transporter/erector. Credit: Ken Kremer/kenkremer.com
Meanwhile pad 40, which was heavily damaged during the Sept. 1 explosion, is undergoing extensive repairs and refurbishments to bring it back online.
It is not known when pad 40 will be fit to resume Falcon 9 launches.
In the interim, SpaceX plans to initially resume launches from the Florida Space Coast at the Kennedy Space Center (KSC) from pad 39A, the former shuttle pad that SpaceX has leased from NASA.
Commercial SpaceX launches at KSC could start from pad 39A sometime in early 2017 – after modifications for the Falcon 9 are completed.
Up close look at a SpaceX Falcon 9 second stage and payload fairing from the JCSAT-16 launch from pad 40 at Cape Canaveral Air Force Station, FL. Both Falcon 9 rocket failures took place inside the second stage. Credit: Ken Kremer/kenkremer.com
The Sept. 1 calamity was the second Falcon 9 failure within 15 months time and called into question the rockets overall reliability. Both incidents involved the second stage helium system, but SpaceX maintains that they are unrelated.
The first Falcon 9 failure involved a catastrophic mid air explosion in the second stage about two and a half minutes after liftoff, during the Dragon CRS-7 cargo resupply launch for NASA to the International Space Station on June 28, 2015 – and witnessed by this author. The accident was traced to a failed strut holding the helium tank inside the liquid oxygen tank. The helium tank dislodged and ultimately ruptured the second stage as the first stage was still firing resulting in a total loss of the rocket and payload.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
