Category: Space Sunday

Space Sunday: “impossible” propulsion, biosigns and life, and taking flight

Posted on by Inara Pey
The NASA Eagleworks EmDrive prototype. Credit: NASA Eagleworks / NASSA Spaceflight Forum
The NASA Eagleworks EmDrive prototype. Credit: NASA Eagleworks / NASA Spaceflight Forum

The radio frequency (RF) resonant cavity thruster, or EmDrive (pronounced “M-drive”) as it is more popularly known, has been a source of much controversy since the idea first came into the public eye around 16 years ago, and the debate has been heating up again over the last few months.

First proposed by British engineer Roger Shawyer in 1999, the EmDrive is supposed to be the world’s first working reactionless drive, a means of generating thrust without the use of any propellant.  Over the years, it has undergone investigation and testing by a number of organisations and agencies before being quietly pushed aside, while some critics have been publicly scathing of the whole idea, labelling it the “impossible drive” as it violates the fundamental law of conservation of momentum (summed up in Newton’s third law, “for every action, there is an equal and opposite reaction”). Even so, research and testing has continued.

The EmDrive supposedly generates thrust by reflecting microwaves between opposite walls of a cone-shaped cavity. In principle, no microwaves or anything else leaves the device, and so it is considered reactionless – although Shawyer states that it isn’t, because the propulsive force is created by a “reaction between the end plates of the waveguide and the Electromagnetic wave propagated within it.”

The attraction of the drive is that were it to work, it could provide an almost endless supply of thrust for satellites and other spacecraft, opening the door to flights to Mars in just 70 days as opposed to the 180-234 days currently required using conventional means. The problem is no-one has actually got the idea to work. Researchers at the at the Northwestern Polytechnical University (NWPU) in Xi’an, China, thought they had in 2012, but further testing in 2014 revealed the thrust apparently created by their EmDrive test rig was actually due to a faulty power connector causing false readings.

Now, however, it seems that a test rig operated by NASA’s Eagleworks Laboratory might actually have demonstrated that in principle an EmDrive could work. News on the testing has actually been leaking out of the laboratory for the past 2-3 months – and has rightfully been met with a healthy dose of scepticism. However, a paper from the team carrying out the research was submitted for peer-review through the Journal of Propulsion and Power, a publication maintained by the American Institute of Aeronautics and Astronautics (AIAA) – and is said to have passed muster.

NASA's Johnson Space Centre, Texas, the home of the Eagleworks Laboratory. Credit: NASA / James Blair
NASA’s Johnson Space Centre, Texas, the home of the Eagleworks Laboratory. Credit: NASA / James Blair

So, does this mean the EmDrive works? Well – no. The peer-review process means that no discernible flaws have been found in the methodology and testing carried out by the Eagleworks team, meriting the idea worthy of further investigation and research. It doesn’t mean fault or error may not yet be found going forward.

One major means of testing the theory of the EmDrive would be to build a working unit and place it in space and see if it works. This is precisely what US engineer Guido Fetta hopes to do. He is planning to place a small  version of his Q-Drive (derived from the EmDrive) in orbit for 6 months aboard a CubeSat (between 10×20×30 cm and 12×24×36 cm in size), and then try over six months to manoeuvre the CubeSat using the drive. He’s not alone; China similarly plans an on-orbit test of an EmDrive prototype, although no dates have been specified for them mission.

Did Spirit Find Signature of Past Martian Life?

NASA's MER rover, Spirit (MER-A) and Opportunity (MER-B) arrived on Mars in January 2004, and Opportunity continues to explore the planet today. Credit: NASA / JPL
NASA’s MER rover, Spirit (MER-A) and Opportunity (MER-B) arrived on Mars in January 2004, and Opportunity continues to explore the planet today. Credit: NASA / JPL

In January 2004, NASA landed two solar-powered rovers, Spirit and Opportunity on Mars. There primary mission was scheduled to last just 90 days – but Opportunity is still operating today, almost 13 years after it arrived on Mars. Sadly, Spirit was not so lucky; in May 2009, it became stuck in a “sand trap” and unable to free itself, eventually losing power as its solar panels could not be oriented towards the winter Sun on Mars, and falling silent in May 2010.

Nevertheless, Spirit gathered a huge amount of data and images, some of which is being re-examined by scientists Steven Ruff and Jack Farmer from Arizona State University as a result of their field expeditions to Chile – and they believe the rover may have come across evidence for past Martian life.

While examining images of a plateau of layered rocks dubbed “Home Plate”, examined by Spirit in 2006, Ruff and Farmer noticed the ground was covered in multiple nodular masses of opaline silica with digitate structures strikingly similar to structures they have encountered within active hot spring/geyser discharge channels at a site in northern Chile called El Tatio.

This is a region which, due a rare combination of high elevation, low precipitation rate, coupled with a high ultraviolet irradiance, is regarded as a potential analogue for past conditions on Mars. What’s more, as a volcanic are, it shares much in common with “Home Plate”, which is believed to be an explosive volcanic deposit created when hot basalt rock came into contact with liquid water. Part of the formation may actually be an extinct Martian fumarole.

An image of "Home Plate" showing a mass of opaline silica nodules, captured by NASA's Spirit rover in 2006, and a photograph showing similar formations at El Tatio, Chile Credit: ASU/Ruff & Farmer
An image of “Home Plate” showing a mass of opaline silica nodules, captured by NASA’s Spirit rover in 2006, and a photograph showing similar formations at El Tatio, Chile Credit: ASU/Ruff & Farmer

The opaline silica Ruff and Farmer found at El Tatio have been shown to be largely of biotic origin; that is, created by microbes. Could this be the same for those Spirit saw at “Home Plate” in 2006? Ruff and Farmer believe it might.

“Although fully abiotic (physical rather than biological) processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures,” the researchers state in a paper on their work. A biosignature is defined by NASA as “an object, substance and/or pattern that might have a biological origin and thus compels investigators to gather more data before reaching a conclusion as to the presence or absence of life.”

A closer view of the structures as images by Spirit in 2006, and a an image of the opaline silica at El Tatio taken at the same distance and resolution. Credit: ASU/Ruff & Farmer
A closer view of the structures as images by Spirit in 2006, and a an image of the opaline silica at El Tatio taken at the same distance and resolution. Credit: ASU/Ruff & Farmer

Ruff and Farmer note that while they cannot prove nor disprove a biological origin for the structures imaged by Spirit at “Home Plate”, they should be regarded as a potential biosignature by NASA’s own definition of the term. They go on to state that the only way to be sure would be for a robust examination to be made of the “Home Plate” location, perhaps by NASA’s upcoming Mars 2020, were it to be sent to that region, or through the examination of another region of Mars which is identified as being geographically and geologically similar.

Virgin SpaceShipTwo Flies

Virgin Galactic’s SpaceShipTwo vehicle, VSS Unity completed its first free flight test on Saturday, December 3rd, after a month’s delay due to a combination of high winds and an unspecified technical issue, which combined to leave the vehicle able to make just a single captive / carry flight with its carry / launch aircraft, WhiteKightTwo.

VSS Unity seen from a chase plane as it glides towards touch-down on Saturday, December 3rd, 2016. Credit: Virgin Galactic
VSS Unity seen from a chase plane as it glides towards touch-down on Saturday, December 3rd, 2016. Credit: Virgin Galactic

The unpowered flight, took place over the Mojave Air and Space Port in California  and was the first in a series of around 10 – the precise number will depend on how well the targets for each flight are met – such tests the vehicle will make before Virgin Galactic move to powered flight tests using their new rocket motor for the vehicle, which has so far only been tested on the ground.

“It’s a happy day to be here,” Virgin Galactic’s founder, Sir Richard Branson said just before WhiteKnightTwo lifted SpaceShipTwo aloft. “We’ve got an exciting year ahead, and this is just the start of it.”

VSS Unity comes to rest on the runway after a successful first first flight test. Credit: Virgin Galactic
VSS Unity comes to rest on the runway after a successful first flight test. Credit: Virgin Galactic

As TGO Flexes Its Muscles, More Ice Found on Mars

ESA’s Trace Gas Orbiter (TGO), which arrived in orbit around Mars in October, has yet to reach its primary science orbit but it is already flexing its muscles.

On November 22nd, as TGO swept over Mars on one of its current 4.2 day elliptical orbits, a test was carried out on its ability to relay data from the Martian surface to Earth, acting as a go-between for both the Curiosity and Opportunity rovers.  As well as carrying a suite of science instruments and camera systems, TGO also carries a communications relay package from NASA called Electra, which allows the spacecraft to successful receive and store communications from NASA’s surface vehicles and then relay them to Earth.

Currently, TGO’s orbit carries it from just 300km (200 mi) above the surface of Mars all the way out to 98,000 km (60,000 mi), limiting its effectiveness  as a communications relay. However, this will be lowered and circularised in the coming months to just 400 km (250 mi) above the planet, at which point TGO will be perfectly positioned to carry out its primary science mission and act as a relay for current and future surface missions, including Europe’s own ExoMars rover.

The relay test came at a time when ESA were working on calibrating TGO’s instruments during the close flights over Mars in each of it current orbits around the planet. These calibration tests included initial use of the orbiter’s “eyes”, the Colour and Stereo Surface Imaging System (CaSSIS), which yielded, in the mission team’s words, “spectacular” results.

CaSSIS is an impressive system, capable of capturing still images and video across a number of colour wavelengths, and in 3D if required. All of CaSSIS’s capabilities were exercised during the test as the orbiter passed over Hebes Chasma, an eight km (5 mi) deep trough just to the north of the mighty Valles Marineris. The images collected during the pass have a resolution of 2.8 metres per pixel. To put that in perspective, it’s the equivalent of flying over New York city at 15,000 km/h (9,375 mph) and simultaneously getting sharp pictures of cars in Philadelphia.

The stereo capabilities of CASSIS will allow scientists to build topographical 3D images of the surface on Mars, such as this test model, built from images of the Noctis Labyrinthus at the north-eastern end of the Vallis Mariners. Credit: ESA / Roscosmos / CaSSIS / UniBE
The stereo capabilities of CaSSIS will allow scientists to build topographical 3D images of the surface on Mars, such as this test model, built from images of the Noctis Labyrinthus at the north-eastern end of the Vallis Mariners. Credit: ESA / Roscosmos / CaSSIS / UniBE

Once TGO reaches its operational orbit towards the end of 2017, CaSSIS will be capable of acquiring 12-20 high-resolution stereo and colour images of selected targets per day.

Meanwhile, NASA’s Mars Reconnaissance Orbiter (TGO) has located another gigantic water ice deposit lying just under the Martian surface. The ice, lying beneath the planet’s Utopia Planitia, was located using MRO’s ground-penetrating Shallow Radar (SHARAD) instrument.

Utopia Planitia: home of a massive water ice deposit the size of New Mexico, and sitting just below the surface of Mars
Utopia Planitia: home of a massive water ice deposit the size of New Mexico, and sitting just below the surface of Mars – click for full size. Credit: NASA

Estimated to be bigger than the US state of New Mexico and containing more water than Lake Superior, it is the second massive ice deposit SHARAD has found in just over a year. The first exists as a deposition averaging 40 metres (604 ft) think, extending almost all the way from the planet’s mid latitudes up to north polar region and covers an area the size of Texas and California combined.

The ice under Utopia Planitia – the landing site for NASA’s Viking 2 mission of the 1970s – is between 80 to 170 metres (260 feet to 560 ft) in thickness, comprises around 85% water ice (the rest being dirt and other deposits), and – most crucially – lies between 1 and 10 metres (3 and 30 ft) beneath the surface, potentially making it an accessible resource for  future human missions to Mars.

NASA Considering Foreshortening Orion Crewed Flight

NASA is considering a shorter mission for the first crewed flight of its Orion Multi-Purpose Crewed Vehicle.

Originally, the flight was to have comprised a “slow cruise” out to the Moon of between 3 and 6 days, followed by three days in lunar orbit before making a similar 3-6 day “slow cruise” back to Earth. However, under the new plans being considered, Orion and its crew would be placed in a high Earth orbit (HEO) with an apogee of 35,000km (21,875 mi), where it would remain for a day, before separating from the Exploration Upper Stage (EUS) of its Space Launch System rocket and suing its Service Module motor to enter a trans-lunar injection orbit, for a single free-return flight around the Moon without ever going into orbit there.

Orion's first mission may now only comprise a flight around the Moon, rather than orbiting it. Credit: Cosmic Pearl
Orion’s first mission may now only comprise a flight around the Moon, rather than orbiting it. Credit: Cosmic Pearl

“We’ve effectively designed this mission to be commensurate with the amount of risk we’re taking with crew on the vehicle for the first time,” Bill Gerstenmaier, NASA associate administrator for human exploration and operations said when announcing the new plan. “We’ve tailored the mission to be appropriate with the risk we’re willing to take.”

Two particular risks worried mission planners: a failure with the Orion’s life support system in what would be its first space-based test with a crew aboard, or a failure with the Service Module’s engine which might leave them stranded in Lunar orbit. The redesigned mission means the life support system can be tested whilst in HEO, and the service module motor only needs to be fired once, when boosting Orion towards the Moon.

The revised Exploration Mission 2 flight plan. Credit: NASA
The revised Exploration Mission 2 flight plan (click to enlarge). Credit: NASA

The change in approach does not affect the Exploration Mission 1 flight, scheduled for 2018. That mission is expected to last around 25 days, with an uncrewed Orion vehicle placed in lunar orbit for several days before it returns to Earth. However, it does open the door to a more gradual approach to extending Orion’s capabilities, with NASA now planning one Exploration Mission a year being flown between 2023 and 2030.

Most of these flights will be cislunar operations, with EM-6 (2026) earmarked as the asteroid rendezvous mission originally scheduled to take place in 2023 as EM-3, but which has been pushed back as a result of delays in the Asteroid Redirect Mission (ARM), its necessary precursor.  EM-10 would mark the likely transition from cislunar missions to BEO (“Beyond Earth Orbit”) missions directed towards Mars, utilising Orion and expanded capabilities such as habitat modules and possible nuclear-powered propulsion units.

Space Sunday: from Earth orbit to Pluto, via Mars

Posted on by Inara Pey
The "supermoon" of November 14th rises over the MS-03 spacecraft the Baikonur Cosmodrome in Kazakhstan, where it was being prepared for launch to the International Space Station
The “supermoon” of November 14th rises over the Soyuz MS-03 spacecraft the Baikonur Cosmodrome in Kazakhstan, where it was being prepared for launch to the International Space Station. Credit: NASA

The second of the three so-called “supermoons” which see out 2016 produced some dramatic photographs and video from around the world. Perhaps one of the most stunning  came from cameras at the Baikonur Cosmodrome in Kazakhstan, monitoring Soyuz MS-03 as it stood on the pad at Launch Complex 1.

As I noted in my last Space Sunday Report, a “supermoon” occurs when the Moon is both full and at perigee – the point in its orbit when it is closest to the Earth as it travels around our planet in an elliptical orbit. Such events occur around every 14 months, and can see the Moon appear to be 14% bigger than its average size in our sky, particularly when seen low on the horizon.

The “supermoon” of November 14th was special because the Moon was about at its closest point to Earth in its orbit – “just” 356,509 kilometres (221,524 miles) from us and the Earth / Moon system is approaching the time of year when it is closest to the Sun (which will occur on January 4th, 2017), thus making the full Moon “extra” bright for those who were able to see it. The next time this will occur will be in 2034. However, December 14th will see another “supermoon”, albeit one at a slightly greater distance away from the Earth, so those who missed November’s – weather permitting – may still get to see one before the year is out. In the meantime, here’s NASA’s footage from Baikonaur  – the film obviously speeded-up 🙂 .

Soyuz MS-03 lifted-off from Baikonur on Friday, November 18th, carrying aloft Russian cosmonaut Oleg Novitskiy, American astronaut  Peggy Whitson and rookie French astronaut Thomas Pesquet. It successfully docked with the International Space Station on Saturday, November 19th, marking the start of the Expedition 50/51 mission aboard the station, the crew sharing space with the Expedition 49/50 crew of mission commander Shane Kimbrough of NASA and Russian cosmonauts Sergey Ryzhikov and Andrei Borisenko, who have been aboard the station since October and who are due to return to Earth in February 2017.

For Whitson, this is a double first: she is the oldest woman to ever fly to the ISS – she will celebrate her 57th birthday in orbit – and, come February, she will be the first woman to command the space station for a second time in its 16-year operational history, having already become the very first woman to take command during Expedition 16 in 2007. She is also NASA’s most experienced female astronaut, with nearly 377 days logged in space, including six space walks totalling 39 hours 46 minutes. By the time she returns to Earth, she will have spent more time in space than any other US astronaut, surpassing the 534-day record set by Jeff Williams in September 2016.

Peggy Witson with Oleg Novitsky and Thomas Pesquet posing for photographs prior to launch. Via: Peggy Whitson
Peggy Witson with Oleg Novitskiy and Thomas Pesquet posing for photographs prior to launch. Via: Peggy Whitson

During their time aboard the station, Whitson, Novitskiy and Pesquest will conduct hundreds of experiments and studies in biology, biotechnology, physical science and Earth science. A particular focus will be recording how lighting impacts the overall health and well-being of station crew members, and how the microgravity environment in orbit affects tissue regeneration in humans and the genetic properties of space-grown plants.

The crew carry with them some special meal time treats as well. Taking a leaf from British astronaut Tim Peake’s book, Pesquest requested fellow countrymen and renowned chefs Alain Ducasse and Thierry Marx develop a special menu for the crew. Highlights include beef tongue with truffled foie gras and duck breast confit.

Soyuz MS-03, piloted by Oleg Novitsky, closes for a docking with the Russian-built Rassvet module on Saturday, November 19th. In the foreground is the Cygnus resupply vehicle which recently arrived at the space station, together with one of its circular solar power arrays
Soyuz MS-03, piloted by commander Oleg Novitskiy, closes for a docking with the Russian-built Rassvet module on Saturday, November 19th. In the foreground is the Cygnus resupply vehicle which recently arrived at the space station, one of its circular solar power arrays partially blocking the view of the incoming Soyuz. Credit: NASA

“We have food for the big feasts: for Christmas, New Year’s and birthdays. We’ll have two birthdays, mine and Peggy’s,” the Frenchman said at the astronauts’ last press conference before the launch.

Pesquest,  a former commercial airline pilot with Air France, is also set to offer some entertainment for the crew: a keen musician, he’s taken his saxophone to the ISS. As part of his work on the station, he has special responsibility for the Proxima research programme of 50 experiments developed by the European Space Agency and the French national space agency, CNES. The programme’s name was suggested by 13-year old Samuel Planas from Toulouse, France, following a nationwide competition among school children. It is taken from Proxima Centauri, with the X in the name both representing the unknown, and the fact that Pesquest is the tenth French astronaut to fly in space.

Oleg Novitskiy, a 45-year-old lieutenant colonel in the Russian Air Force, is also on his second mission aboard the ISS, having previously served as the Soyuz TMA-06M commander during the flight to the ISS, and as the station’s flight engineer during Expedition 33/34. He has spent 143 days 16 hours and 15 minutes in space.

Continue reading “Space Sunday: from Earth orbit to Pluto, via Mars” →

Space Sunday: “super Earth”, “supermoon”, and Orion’s future

Posted on by Inara Pey
An artist's impression of a "super Earth" type planet in orbit around a red dwarf star. Credit: NASA / Dana Berry.
An artist’s impression of a “super Earth” type planet in orbit around a red dwarf star. Credit: NASA / Dana Berry.

In a couple of recent Space Sunday reports, I covered the discovery of an Earth-size planet orbiting  our nearest stellar neighbour, the red dwarf Proxima Centuari (see here and here). Red dwarfs  are a class of star which has proven rich ground for planet hunters  –  and this has once again proved the case.

The European Southern Observatory ESO), one of the leading hunters of exoplanets, has  reported the discovery of a “super Earth”, a sold planetary body with roughly five times the mass of Earth. It is orbiting GJ 536, an M-class red dwarf star some 32.7 light years from the Sun. The planet is orbiting its parent once every 8.7 days, at a distance of 0.06661 AU.

The planet was discovered using a pair of instruments operated by ESO: the High Accuracy Radial velocity Planet Searcher (HARPS), mounted on ESO’s 3.6 metre telescope at the La Silla Observatory in Chile, and its sister instrument, HARPS-N, at the La Palma Observatory in Spain. The findings from these instruments were combined with photometric data from the All Sky Automated Survey (ASAS), which has observatories in Chile and Maui, to confirm the existence of the planet.

Red dwarf stars are entirely convective in nature, making them extremely volatile in nature, and subject to massive stellar flares. Credit: NASA/CXC/M.Weiss
Red dwarf stars are entirely convective in nature, making them extremely volatile in nature, and subject to massive stellar flares. Credit: NASA/CXC/M.Weiss

However, its was no rapid-fire discovery. In all, data from over eight years of observations of the star went into confirming the presence of the planet. Such is the extended period of observations, that the science team were able to gather a huge amount of spectroscopic data on the star. This has revealed it has a rotational period of about 44 days, and magnetic cycle that lasts less than three years. By comparison, the Sun has a rotational period of 25 days and a magnetic cycle of 11 years.

This indicates that GJ536 is, in keeping with most red dwarf stars, exceptional volatile. Such stars are so small, all activity within them is entirely convective in nature, which gives rise to massive stellar flares. So while the new planet may well have “earth” in its description, it is unlikely to be “Earth like”, particularly given its relatively close proximity to its parent star.

Not much more is known about the planet at this point, but this is liable to change over time, and in the meantime, the survey team will continue to gather data on GJ 536 to see if it is home to other planets, such as gas giants further away from it.

November’s Supermoon

A dramatic supermoon is seen behind the Christ the Redeemer statue in Rio de Janeiro, in May 2012. Credit: AP Photo/Victor R. Caivano
A dramatic supermoon is seen behind the Christ the Redeemer statue in Rio de Janeiro, in May 2012. Credit: AP Photo/Victor R. Caivano

The last three months of 2016 are marked by three so-called “supermoons”, and the biggest will be in the night skies on Monday 14th November 2016.

The Moon is in an elliptical orbit around the Earth, at apogee, the point furthest from the Earth, it is between 404,000–406,700 km (252,500-254,187 mi) from Earth. At perigee, the point closest to the Earth, the Moon is between 356,400–370,400 km (222,500-231,500 mi) away. A “supermoon” occurs when the Moon is both full and at perigee, when it can appear up to 14% large in diameter than “normal” full moons.

Apogee and preigee in the Moon's orbit around Earth. Credit: NASA
Apogee and perigee in the Moon’s orbit around Earth. Credit: NASA

“Supermoons” aren’t actually rare events; they take to occur once every 14 months on average.  However, the supermoon on November 14th, scores double. Not only will be “just” 356,509 kilometres (221,524 miles) from Earth, pushing it to that 14% increase in apparent size, but also because the Earth/Moon system is approaching the time of year when it is closest to the Sun (which will occur on January 4th, 2017). Therefore, the Moon will be receiving more sunlight than average, further boosting its apparent brightness.

Together, these two events mean that the Moon will be at its “largest” and brightest in the sky since 1948. The next comparable event will not occur again until 2034 – although there will be a further “supermoon” on December 14th, when the Moon again reaches its full phase, but it will be slightly further away from the Earth in its orbit at that time, so not quite as “super”.

How the Moon can appear to differ i size at apogee (the point furthest from Earth in its orbit) and perigee (the point in its orbit closest to Earth). Credit: Catalin Paduraru
How the Moon can appear to differ in size at apogee (the point furthest from Earth in its orbit) and perigee (the point in its orbit closest to Earth). Credit: Catalin Paduraru

Continue reading “Space Sunday: “super Earth”, “supermoon”, and Orion’s future” →

Space Sunday: of moons, storms and rockets

Posted on by Inara Pey
A joint Belgian-French-Japanese study has provided the strongest evidence yet for the Martian moons being the result of a massive collision between the planet and other object very early in the solar system's history
The traditional theory of the Moon’s formation is that a Mars-sized body grazed the young Earth, throwing of a cloud of material which  eventually condensed into the Moon. Credit: NASA

We’re all familiar with the Moon, Earth’s cosmic companion. So familiar with it in fact, that we probably all think we know the theory behind how it got to be where it is – the result of a “giant impact” far back in Earth’s early history. However, a new study, published on October 31st in Nature, suggests what actually led to the creation of the Moon was possibly a lot  more elegant than previously realised.

The Moon is actually quite unique among the solar system’s satellites. It’s relatively large when compared to its parent planet, and it is a made of pretty much the same stuff, minus some more volatile compounds that evaporated long ago. Other moons tend to be a lot more chemically diverse when compared to one another and their parent worlds.

The accepted theory of lunar formation has it that not long after primordial Earth formed, a Mars-sized object grazed it, throwing off a mass of material from which the Moon subsequently condensed. This impact set the angular momentum for the Earth-moon system, and gave the early Earth a five-hour day. Then, over the aeons, the Moon slowly receded from the Earth (as it continues to do so to this day), and Earth’s rotation has slowed to our current 24-hour day.

The Moon is is an elliptical orbit around the Earth which varies from 364,397 km at its closest, to 406,731 km at its most distant. When it’s full and at its closest point to Earth (perigee), the Moon can look over 10% bigger, and 30% brighter than when it’s at a more distant point in its orbit (apogee). However, such is the momentum of the Moon's oribt, it is actually slowly moving further and further away from Earth, as it has been throughout its history
The Moon is in an elliptical orbit around the Earth which varies from 364,397 km at its closest, to 406,731 km at its most distant. When it’s full and at its closest point to Earth (perigee), the Moon can look over 10% bigger, and 30% brighter than when it’s at a more distant point in its orbit (apogee). However, such is the momentum of the Moon’s orbit, it is actually slowly moving further and further away from Earth, as it has been throughout its history. Credit: Wikipedia

It’s a theory all worked out be a combination on mathematics based on the moon’s current orbit, the angular momentum of the Earth-Moon system, the influence of various tidal forces, a little bit of guesswork, etc.  However, it does have a couple of holes in it.

The first is that if the Moon was formed as a result of material set free during a slight collision between Earth and another body, then that material should have been a mix of debris from both Earth and the other body, giving rise to a lunar composition that should be at least somewhat different to that of Earth. The second is that if the Moon condensed from a disk of material rotating around Earth’s equator, it should be in orbit over the equator – but instead, its orbit is tilted 5 degrees off the equator.

Both of these issues have previously been explained in terms of “intervening steps” between what we see today and the original  “giant impact”. However, a team of scientists led by Sarah Stewart, professor of earth and planetary sciences at the University of California, have posited an alternative explanation, which requires no “intervening steps”, but always natural mechanics to explain everything.

In their model, the “giant impact” still occurs –  but it completely destroys the nascent Earth and whatever hit it, leaving a mass of vaporised and molten material  orbiting the Sun, which eventually condenses to form a “new” Earth and the Moon – thus giving them similar chemical compositions. Initially, the Earth would have likely been tipped so its axis was pointing towards the Sun while spinning in a two-hour day.

Then, as angular momentum was dissipated through tidal forces, the Moon started receding from Earth, eventually reaching a point called the “LaPlace plane transition”. At this point the forces from the Earth on the Moon became less important than gravitational forces from the sun, resulting in some of the angular momentum of the Earth-Moon system transferring to the Earth-Sun system, causing the Earth to tip “upright”, while leaving the Moon in a very highly inclined orbit relative to Earth’s equator. However, as the Moon continued to slowly and naturally recede from the Earth, it eventually reached the Cassini transition, gradually reducing the Moon’s angle of inclination relative to the Earth’s equator, bringing it to the five-degree offset we see today.

Thus, with this model, no exotic intermediary steps are required to account for the Moon’s composition or why it is where it is today; everything can be explained through the application of mathematics and planetary mechanics, offering a compelling alternative to the accepted theory of lunar evolution.

China Launches the Long March 5 Heavy Lifter

China's Long March 5 (l) and Long March 7 (r) next generation launch vehicles
China’s Long March 5 heavy lift launch vehicle (l) is the centrepiece of China’s long-term space ambitions alongside the medium lift Long March 7 (r), which entered service earlier in 2016. Credit: CCTV

China’s newest and biggest heavy-lift rocket, the Long March 5 (Chang Zheng-5) lifted-off from the Wenchang launch centre on Hainan Island, off China’s southern coast, at 12:43:14 UT or 20:43 Beijing time on Thursday, November 3rd, carrying an experimental satellite designed to test electric-propulsion technology.

With a 25 tonne low Earth orbit payload capacity, the Long March 5 stands on a par with the current crop of heavy lift launch vehicles in operation around the world. The product of two decades of research and development, it is destined to become a centrepiece of China’s growing space ambitions.

Among its may missions, the Long March 5 will play a leading role in the construction of China’s upcoming space station, starting with the launch of the core Tianhe (“Harmony of the Heavens”) module in 2018. When completed in 2022, the 60-tonne station will comprise the core module supported by the Wentian (“Quest for the Heavens”) and Mengtian (“Dreaming of the Heavens”) pressurised experiments modules, all of which will be linked by a multi-port adaptor / EVA airlock.

Continue reading “Space Sunday: of moons, storms and rockets” →

Space Update: Planet Nine, “signalling” stars and a quick round-up

Posted on by Inara Pey
Planet Nine, if it exists,could equal Neptune in size, and orbits the Sun 200 times further away than Earth. Credit: Caltech / R. Hurt
Planet Nine, if it exists,could equal Neptune in size, and orbit the Sun 200 times further away than Earth. Credit: Caltech / R. Hurt

In January and February 2016, I wrote about Planet Nine (or Planet X, George, Jehoshaphat, or Planet of the Apes, depending  your preference), the Neptune-sized world believed to be orbiting the sun on the very edge of the solar system in a highly eccentric orbit. Since then, the search for this mysterious world has continued, and while it has yet to be located, evidence that it exists has been mounting. Not only that, but astronomers now believe it might explain why the solar system is “tipped”.

The Hunt started after Mike Brown, a leading planetary astronomer at the California Institute of Technology (Caltech), and his colleague Konstantin Batygin developed a computer model which showed that the very eccentric orbits of six Trans-Neptunian Objects (TNOs) located in what is called the scattered disk,  a sparsely populated region of space between 30 100 AU from the sun, overlapping with the Kuiper belt, could have been due to the influence of a massive, distant planet. At the time, they noted that if the model was correct, other TNOs would likely  occupy equally distinct orbits.

A planet averaging about 10 times as massive as Earth, called Planet Nine could explain the paths of six distant objects in the solar system with mysterious orbits
A planet averaging about 10 times as massive as Earth, called Planet Nine could explain the paths of six distant objects in the solar system with mysterious orbits. Credit: Caltech / R Hurt

At the joint European Planetary Science Congress (EPSC) and American Astronomical Society’s Division for Planetary Sciences (DPS) in October, it was revealed more TNOs fitting the model have been discovered over the past several months. Two of them,  2013 FT28 and 2014 SR349, precisely fit the same type of orbit seen the original six objects used by Brown and Batygin model. Five more have been found in orbits which are effective perpendicular to Planet Nine’s believed orbit around the Sun, something predicted by the computer model.

All of this is helping to narrow down Planet Nine’s potential orbit around the Sun, and the arc of that orbit where it might be found. So much so that Batygin, Brown have teamed with original proponents for Planet Nine Chad Trujillo and Scott Sheppard to use the 8-metre Subaru Telescope atop Mauna Kea in Hawaii to carry out a  search of the night sky. Sheppard and Trujillo are also using two telescopes in Chile to search the possible sweep of the planet through the southern hemisphere’s night sky. And they are not alone.

The Brown / Batygin model for Planet Nine indicated the planet would cause some TNOs to ine in orbits perpendicular to the planet's own eccentric orbit around the Sun - and five such object have now been discovered (shown in teal, with the original TNOs possibly influenced shown in magenta. Credit: Caltech
The Brown / Batygin model for Planet Nine indicated the planet would cause some TNOs to lie in orbits perpendicular to the planet’s own eccentric orbit around the Sun – and five such object have now been discovered (shown in teal, with the original TNOs possibly influenced shown in magenta. Credit: Caltech

Also at the planetary conference, graduate student Elizabeth Bailey, using Brown and Batygin’s data presented a paper proposing how the odd tilt to the solar system’s major planets relative to the Sun might be due to Planet Nine.

With the exceptional of Mercury, all the major planets in the solar system orbit along a plane tilted by about six degrees from the Sun’s equator. This suggests either the Sun was somehow tipped on its axis in the past, or the planets have been pulled from their original alignment along the Sun’s equatorial plane. Of these two ideas, the preferred option has been for exotic interactions between the early Sun’s magnetic field and the primordial disk of gas surrounding it, inclining the latter, which then formed the planets. However, Bailey’s simulations suggest that a large body occupying Planet Nine’s predicted orbit could have had sufficient influence on the Sun over some 4 billion years to have slowly tipped it over by six degrees. Bailey’s hypothesis was supported by a  Brazilian team of astronomers, who used a different analytical method while working independently from her, and reached the same conclusion.

As it might be: estimates concerning Planet Nine's possible size, mass, etc., should it exist. Credit: Space.com / Karl Tate
As it might be: estimates concerning Planet Nine’s possible size, mass, etc., should it exist. Credit: Space.com / Karl Tate

Even so, some remain sceptical that the mysterious world exists. “I give it about a 1% chance of turning out to be real,” says astronomer JJ Kavelaars, of the Dominion Astrophysical Observatory in Victoria, Canada. Interestingly, his fellow researcher and collaborator Cory Shankman,  has created models with the exact orbits of the original six TNOs used by Brown and Batygin, and found that a massive planet would not maintain their tell-tale clustering for long periods.

Thus, the search for the solar system’s mysterious Planet Nine, continues.

ETs Phone Home?

Are aliens sending signals using their own stars? That’s what might be happening, according to astrophysicists Ermanno Borra and Eric Trottier, from Laval University in Quebec; although they admit it’s only one possible explanation for what they appear to have discovered.

It was in 2012 that Borra predicted intelligent aliens might use the light from their own stars to signal their existence to the cosmos. Using data from the Sloan Digital Sky Survey, Borra and Trottier analysed the spectra of 2.5 million stars to see if this might be the case – and found 234  which seem to be broadcasting a signal of the kind predicted by Borra.

The “signals” are pulses in the stars’ light, separated by a constant time interval. What’s more, all 234 stars are predominantly in the F2 to K1 spectral range, which is the small range of stars centred on the spectrum of our own life-supporting Sun, and thus the broad group of stars thought might support life on planets orbiting them.

The Sloan Digital Sky Survey telescope, New Mexico. Credit: SDSS / Fermilab Visual Media Services / NASA
The Sloan Digital Sky Survey telescope, New Mexico. Credit: SDSS / Fermilab Visual Media Services / NASA

However, as Borra and Trottier note in their paper – which has yet to be comprehensively peer-reviewed – the pulses could be the result of natural factors such as rotational transitions in molecules or the Fourier transform of spectral lines. It might even be due to rapid pulsations in the stars themselves. Nevertheless Borra and Trottier have tended to dismiss rotational transitions on the grounds that such behaviour isn’t common to these types of star. They also think it unlikely a Fourier transform is responsible.

Instead, they lead towards either the “signals”  being an artefact produced by data reduction on the part of the Sloan instrument, or the work of ET, with a slight emphasis towards the ET side of their thinking.  Others, having read their paper, are far more sceptical.

“It seems unlikely that 234 separate alien societies would be sending out such similar signals more or less simultaneously” Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California said. “It would be like expecting us to send the same signals as the Abyssinians — it doesn’t make a whole lot of sense.” Instead, Shostak leans towards the data reduction explanation; as does Occam’s Razor.

But a further possible explanation has been suggested: that the signals are due to highly peculiar chemical compositions in a small fraction of galactic halo stars which has  never been previously encountered. While not as exotic as aliens using their stars as signalling devices, should this prove to be the case, it would still be a remarkable new discovery.

Continue reading “Space Update: Planet Nine, “signalling” stars and a quick round-up” →

Space Sunday: success, loss and safe modes

Posted on by Inara Pey
A colour-enhanced image of Jupiter's south pole, created by "citizen scientist" Alex Mai, as a part of the public Junocam project. using data from Juno's JunoCam instrument. Credit: NASA/JPL / SwRI / MSSS / Alex Mai - see later in this article for an update on the Juno mission
A colour-enhanced image of Jupiter’s south pole, created by “citizen scientist” Alex Mai, as a part of the public JunoCam project. Credit: NASA/JPL / SwRI / MSSS / Alex Mai – see later in this article for an update on the Juno mission

On Wednesday, October 19th, 2016, the European Space Agency (ESA) attempted, for them, a double first: placing a vehicle successfully in orbit around Mars (the Trace Gas Orbiter, or TGO) and landing a vehicle on the planet’s surface (the Schiaparelli demonstrator).

Launched in March 2016, TGO is the second European orbiter mission to Mars, the first being Mars Express, which has been operating around the red planet for 12 years. TGO’s mission is to perform detailed, remote observations of the Martian atmosphere, searching for evidence of gases which may be possible biological importance, such as methane and its degradation products. At the same time, it will to image Mars, and act as a communications for Europe’s planned 2020 Mar rover vehicle.

October 16th, 2016: the Schiaparelli EDM separates from ESA's TGO, en-route for what had been hoped would be a safe landing on Mars. Credit: ESA
October 16th, 2016: the Schiaparelli EDM separates from ESA’s TGO, en-route for what had been hoped would be a safe landing on Mars. Credit: ESA

TGO’s primary mission won’t actually start until late 2017. However, October 19th marked the point at which the vehicle entered its preliminary orbit around Mars.  Orbital insertion was achieved following a 139-minute engine burn which slowed the vehicle sufficiently  to place  it in a highly elliptical, four-day orbit around Mars. Early next year, the spacecraft will begin shifting to its final science orbit, a circular path with an altitude of 400 km (250 mi), ready to start its main science mission.

On Sunday, October 16th, prior to orbital insertion, TGO had bid farewell to the 2-metre diameter Schiaparelli  Entry, Descent and Landing Demonstrator Module (EDM), which it had carried to Mars. The EDM was specifically designed to gather data on entry into, and passage through, the Martian atmosphere and test landing systems in preparation for ESA’s 2020 rover mission landing. 

Schiaparelli's route to the surface of Mars. Credit: ESA
Schiaparelli’s route to the surface of Mars (click for full size). Credit: ESA

Once separated from TGO, Schiaparelli travelled ahead of the orbiter, entering the Martian atmosphere at a speed of 21,000 km/h (13,000 mph; 5.8 km/s / 3.6 mi/s), at 14:42 UT on October 19th. After using the upper reaches of the Martian atmosphere to reduce much of its velocity, Schiaparelli should have proceeded to the surface of Mars using a mix of parachute and propulsive descent, ending with a short drop to the ground, cushioned by a crushable structure designed to deform and absorb the final touchdown impact. Initially, everything appeared to go according to plan. Data confirmed Schiaparelli had successfully entered the Martian atmosphere and dropped low enough for the parachute system to deploy. Then things went awry.

Analysis of the telemetry suggests Schiaparelli prematurely separated from its parachute, entering a period of free fall before the descent motors fired very briefly, at too high an altitude and while the lander was moving too fast. Shortly after this, data was lost. While attempts were made to contact the EDM using ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter (MRO) it was not until October 20th that Schiaparelli’s fate became clear.

Images taken by MRO  of Schiaparelli’s landing zone revealed a new 15x40m (49x130ft) impact crater, together with a new bright object about 1 kilometre south of it. The crater is thought to be Schiaparelli’s impact point, and the latter the lander’s parachute and aeroshell.

In releasing the NASA images on October 21st, the European Space Agency stated,”Estimates are that Schiaparelli dropped from a height of between 2 and 4 km (1.4-2.4 mi), impacting at a  speed greater than 300 km/h (186 mph). It is also possible that the lander exploded on impact, as its thruster propellant tanks were likely still full.”

Point of impact: on the left, images of Schiaparelli's landing zone taken in May 2016 and on October 20th, 2016, superimposed on one another, the October 20th image clearing showing an impact feature. On the right, an enlarged view of the same two images, showing the impact feature and, south of it, the white canopy of Schiaparelli's parachute. Credit: NASA/JPL / MSSS
Point of impact: on the left, images of Schiaparelli’s landing zone taken in May 2016 and on October 20th, 2016, superimposed on one another. The October 20th image clearly shows an impact feature with a bright object to the south, thought to be Schiaparelli’s parachute canopy. On the right, an enlarged view of the same two images. Credit: NASA/JPL / MSSS

While the lander carried a small suite of science instruments which would have been used to monitor the environment around it for a few days following the landing, the major part of the mission was to gather data atmospheric entry and the use of parachute and propulsive descent capabilities. ESA believe this part of the mission to have been a success, even with minimal data gathered on the propulsive element of the descent.

In the meantime, TGO is currently on a 101,000 km x 3691 km orbit (with respect to the centre of the planet). It is fully functional, and will undertake instrument calibration operations in November, prior to commencing the gentle aerobraking manoeuvres designed to reduce and circularise its orbit around Mars.

Continue reading “Space Sunday: success, loss and safe modes” →