Space Sunday: to touch the face of the Sun

Ignition! The three main stages of the Delta 4 Heavy fire, starting the Parker Solar Probe on its mission to examine the Sun up close and personal. Credit: NASA

On the morning of Sunday, August 12th, 2018, NASA launched the Parker Solar mission, which it describes as being “to touch the face of the Sun”. It will be the first mission to fly through the Sun’s corona – the hazardous region of intense heat and solar radiation in the Sun’s atmosphere that is visible during an eclipse, and it will gather data that could help answer questions about solar physics that have puzzled scientists for decades. Over the course of its initial 7-years the Parker Solar Probe mission will allow us to better understand the fundamental processes going on in, on, and around the Sun, improving our understanding how our solar system’s star influences, affects and changes the space environment, through which we travel as the Earth orbits the Sun.

The probe and mission are named for Dr Eugene Parker, an American solar astrophysicist, who in 1958 first posited  the theory of the supersonic solar wind, and who also predicted the Parker spiral shape of the solar magnetic field in the outer solar system. Now 91, he was present at NASA’s Kennedy Space Centre as a distinguished guest of the agency, to witness the probe’s launch, the mission (and vehicle) being the first in NASA’s history to be named after a still-living person.

The Delta 4 Heavy carrying the Parker Solar Probe sits on the pad of Space Launch Complex (SLC) 37 at Canaveral Air Force Station, Florida, following the aborted launch attempt of Saturday, August 11th, 2018. Credit: Vikash Mahadeo / SpaceFlight Insider

Lift-off came at 03:31 EDT (6:31 GMT / 7:31 BST) on Sunday, August 12th, after the initial launch attempt was scrubbed on Saturday, August 11th, when a troubled countdown was halted just one-minute, 55 seconds before the engines on the United Launch Alliance (ULA) Delta 4 Heavy rocket were to ignite. The halt was called following a gaseous helium red pressure alarm, and investigations into its cause extended beyond the 65-minute launch window, resulting in the launch scrub.

The Sunday morning launch countdown proceeded without any significant hitches, and the Delta 4 Heavy – the most powerful rocket in ULA’s fleet of launch vehicles, comprising 3 Delta 4 first stages strapped side-by-side, the outer two functioning as “strap-on boosters” – lit up the Florida coastline as it took to the early morning skies.

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Although a flight to the Sun might sound an easier proposition than reaching the outer solar system, it actually isn’t; it actually requires 55 times more launch energy than a launch to Mars. Hence why the relative small and light Parker Solar Probe, weighing just 685 kg (1,510 lb) at launch, required the massive Delta 4 and a rarely-used Star 48BV variant of the Payload Assist Module (PAM).

Originally developed as the upper stage for Delta 2 launch vehicles in the 1965, the Star family of solid-fuel PAM units were commonly used with the space shuttle for satellite launches from orbit: the shuttle would carry them aloft, release the PAM / Satellite combination, then move to a safe distance before the PAM motor was ignited to push the satellite on to its require Earth orbit. For the Parker Solar Probe, the Star 48BV was used to impart as much velocity as possible into the vehicle at is starts on it journey.

Dr. Eugene Parker, now 91, watches the launch of the probe named in his honour as it lifts-off from SLC-37, Sunday, August 12th, 2018. Credit: NASA / Glenn Benson

What makes a flight to the Sun so hard is that the Earth is moving “sideways” relative to the Sun at about 107,000 km/h (67,000 mph), and the probe has to cancel out a whopping 84,800 km/h (53,000 mph) of that “sideways” motion as it makes its way to the Sun in order to achieve orbit. At the same time, the probe needs to gain velocity as it moves in towards the centre of the solar system in order for it to balance the Sun’s enormous gravitational influence and achieve the required elliptical orbit.

The use of the Delta 4 / Star 48BV combination got both of these requirements started, by pushing the probe towards Venus in an arc that will both start to shed the “sideways” velocity, whilst also accelerating the craft in towards the Sun. But it will be Venus that does the real grunt work for the mission.

On October 1st, 2018, the probe will make the first of a series of flybys of Venus, where it will use the Venusian gravity to shed still more of the angular velocity imparted by Earth’s orbit and increase its velocity towards the Sun.

In all, seven such fly-bys of Venus will occur  over the 7 year primary mission for the probe, and while only the first is required to shunt the vehicle into its core heliocentric orbit, the remaining six play an important role in both maintaining the vehicle’s average velocity across the span of the mission and in gradually shrinking its elliptical orbit around the Sun as the mission progresses.

The first pass around the Sun  – and the start of the science mission – will occur in November / December 2018. At perihelion, the vehicle will be just 6.2 million km (3.85 million mi) from the Sun’s photosphere (what we might call its “surface”). During this time, the vehicle will be well within the corona, and will also temporarily become the fastest human-made vehicle ever made, achieving a velocity of around 700,000 km/h (430,000 mph) – that’s 200 km per second (120 mi/s), or the equivalent of travelling between London and Tokyo in around 50 seconds! At aphelion – the point furthest from the Sun, and brushing Earth’s orbit, the craft will be travelling a lot slower.

The corona is a very hot place – hotter than the “surface” of the Sun, however, it is also comparatively thin as far as an “atmosphere” goes. The distance at which Parker Solar Probe will be travelling from the Sun at perihelion, combined with its speed, mean that the ambient heat of the corona isn’t a significant issue. Direct sunlight radiating out from the Sun, however, is a significant problem.

Continue reading “Space Sunday: to touch the face of the Sun”


Space Sunday: questions of life, and the “Commercial Nine”

A computer generated terraformed Moon. While it may not have looked like this in its past, the Moon may once not only have had an atmosphere and liquid water on its surface, it may have had conditions suitable for life. Credit: unknown, via Lunar wikia

Throughout human history – and outside of flights of fancy – the Moon has always been thought of as an airless ball of rock, tidally locked to Earth so that it shows the same, almost never-changing face to us in the night sky. But it may not always have been so.

In recent years, our perceptions of the Moon have been changing as a result of a number of studies and missions. In 2009, for example, India’s first lunar mission, Chandrayaan I, produced a detailed chemical and mineralogical map of the lunar surface, revealing the presence of water molecules in the lunar “soil”. In that same year, NASA launched a pair of missions to the Moon, the Lunar Reconnaissance Orbiter (LRO) mission and the Lunar Crater Observation and Sensing Satellite (LCROSS).

LCROSS was a small satellite designed to follow the upper stage of the rocket used to launch it and LRO to the Moon and analyse the plume of debris created by the impact of the upper stage with Cabeus crater in the Moon’s south polar region. The impact came with a kinetic energy equivalent of an explosion created using 2 tons of TNT, and LCROSS recorded strong evidence of water within the resultant impact plume.

For its part, LRO entered lunar orbit to commence a comprehensive campaign of mapping, imaging and probing the Moon’s surface and environment. In doing so, it further confirmed the presence of abundant concentrations of water in the lunar south polar regions. At the same time and LRO has been studying the Moon, an ongoing analysis of the rock samples brought back by the Apollo astronauts has revealed strong evidence for a large amount of water being present in the lunar mantle – possibly as much as is present in Earth’s upper mantle.

An artist’s impression of the 2009 LCROSS satellite “shadowing” the Centaur upper stage used to launch both it and the Lunar Reconnaissance Orbiter (LRO), as the upper stage heads towards its lunar impact. Credit: NASA

These results and findings have given rise to the idea that very early on in the Moon’s history conditions could have been very different to how it is now. In the immediate period following the Moon’s creation (roughly four billion years ago), there are a period when it was very volcanically active (about 3.8-3.5 billion years ago), releasing considerable amounts of superheated volatile gasses, including water vapour, from its interior. This outgassing could have given rise to an atmosphere around the Moon dense enough to support that water vapour condensing out into liquid on the surface which could have conceivably lasted for several million years whilst the atmosphere remained dense enough to support it, before it either (largely) evaporated or retreated underground to eventually freeze.

In their new study, published in July 2018, Dirk Schulze-Makuch, a professor of astrophysics at Washington State University, USA, and Ian A. Crawford, a professor of planetary science and astrobiology at Birkbeck College, University of London, UK, review the evidence for liquid water to have been present on the Moon and examine the potential for it to have been life-bearing. In particular, they note that when all is said and done, if the early conditions on the Moon did give rise to a dense atmosphere and a water-bearing surface, then the conditions there wouldn’t have been that different to those being experienced on Earth when life here was starting up, and would have occurred in the same time frame.

A false-colour image of the Moon’s south pole highlights areas that are in permanent shadow. These account for around 3% of the south polar region, and could be places where frozen water exists beneath the surface (note the blue colour is not indicative of water, but simply a means of highlighting the shadow spots). Credit: NASA Goodard Space Centre

It looks very much like the Moon was habitable at this time. There could have actually been microbes thriving in water pools on the Moon until the surface became dry and dead.

Dirk Schulze-Makuch, co-author of Was There an Early Habitability Window for Earth’s Moon?,
quoted in Astrobiology Magazine

So does that mean life, however transient, got a start on the Moon? Possibly; however, some have suggested rather than giving rise to life directly, the conditions on that early Moon might have been ideal for life from Earth to gain a toe-hold.

As noted, the period when the Moon may have had its dense atmosphere coincided with life starting on Earth in a period referred to as the Late Heavy Bombardment, (4.1 and 3.8 to 3.5 billion years ago). During that time, bacteria such as cyanobacteria were believed to be already present on Earth, even as it was being bombarded by frequent giant meteorite impacts (hence the period’s name). So the suggestion is that this bombardment could have thrown chunks of bacteria-laden rock into space, where they were “swept up” by the Moon, transferring the bacteria to its surface, where it might have taken hold.

It’s unlikely that if it go started, life on the Moon got very far; within a few million years after the end of the Moon’s volcanic period the atmosphere would have been lost, and conditions would have become far too harsh for life to endure. However, in noting this, Crawford and Schulze-Makuch use their study as a call for a more robust study on the potential ancient habitability of the Moon, including a hunt for possible biomarkers.

Not related to the article: this image taken by LRO in 2011 highlights the Apollo 17 landing site and areas explored by Gene Cernan and Harrison Schmitt in 1972. Credit: NASA / NASA Goddard Space Centre.

Such an endeavour would likely be focused on the lunar south polar regions, simply because of the potential abundance of subsurface frozen water there. And as it is, NASA, India and China are already committed to studying the region in great detail. NASA will initially do so from orbit, while the Indian Chandrayaan-2 mission will attempt to place a lander and rover close to the Moon’s south pole in 2019. Also in 2019, China will send its  Chang’e 5 mission to the Moon’s north polar regions to gather and return around 2 kg of rock samples for detailed analysis on Earth.

Continue reading “Space Sunday: questions of life, and the “Commercial Nine””

Space Sunday: an eclipse, a space ship, lasers and a birthday

The total lunar eclipse as seen over the columns of the acropolis. Greece, on July 27th, 2018. Credit: Valerie Gache / AFP Getty Images

Friday, July 27th marked the longest lunar eclipse of the 21st century, which was visible from southern Africa, Australia, and Madagascar, Europe, South Asia and South America. Although many of us in the UK largely (and typically!) missed out, as the summer heat wave gave way to rain and clouds, a bit of a double blow, given we were just outside the reach of totality.

For about half the world, the Moon was partly or fully in Earth’s shadow from 17:14 to 23:28 GMT; six hours and 14 minutes in all, with the period of totality – when the Moon lies entirely within the Earth’s shadow, and so is at its darkest – lasting from 19:30 to 21:13 GMT.

Another view of the eclipse from Greece: the Moon appears between the ancient gods Apollo and Hera in Athens. Credit: Aris Messinisaris / AFP / Getty Images

In a special treat, Mars, which is currently at opposition, sitting on the same side of the Sun as Earth, and thus at its closest to Earth (roughly 92 million km /  57 million mi), was visible just below the eclipsed Moon, appearing as a bright “star”. Those blessed with clear skies also had the treat of Saturn, Jupiter and Venus being visible in the sky as well.

The reason the eclipse lasted so long was that the alignment between Sun, Earth and Moon meant that the Moon was passing right across the middle of the disc of shadow cast by the the Earth. This also meant this eclipse created a particularly strong blood Moon. This is a phenomena caused by the lensing effect of the Earth’s atmosphere scatters blue light from the Sun outwards, whilst refracting red light inwards, so the Moon appears rusted as  seen from Earth.

The July 2018 blood moon, seen from Siliguri, India, on July 28th, 2018 (local time). Credit: Diptendu Duttadiptendu Dutta / AFP /Getty Images

Virgin Galactic Reach Mesosphere for the 1st Time

VSS Unity took to the skies on July 26th, 2018, and reached its highest altitude yet: 52,000 metres (170,800 ft), the highest any Virgin Galactic vehicle has thus far reached.

VMS (Virgin Mother Ship) Eve, the WhiteKnightTwo carrier aircraft, took off from the Mojave Spaceport at 15:45 GMT and climbed to an altitude of 14,000 metres (46,500 ft), prior to releasing Unity, which dropped clear prior to its single rocket motor being ignited. The engine burned for some 42 seconds, powering the vehicle into a near vertical ascent and a speed that reached Mach 2.47.

This was enough to propel Unity on a parabolic flight that topped-out at 52,000 m, inside the mesosphere, which spans heights from approximately 10 km (33,000 ft; 6.2 mi) to 100 km (62 mi; 330,000 ft), representing the heights to which Virgin Galactic flights will typically carry fare-paying passengers so they can enjoy around 5 minutes of weightlessness.

VSS Unity mid-flight on July 26th, 2018, as seen from a chase plane. Credit: Virgin Galactic / / Trumbull Studios

It was a thrill from start to finish. Unity’s rocket motor performed magnificently again, and Sooch [co-pilot Mike Masucci] pulled off a smooth landing. This was a new altitude record for both of us in the cockpit, not to mention our mannequin in the back, and the views of Earth from the black sky were magnificent.

– Virgin Galactic’s chief pilot, Dave Mackay

The mesosphere is sometimes referred to the “ignorosphere”, as it sits above the range of instrument carrying balloons, but well below the height from which it can be studied from space, and so remains one of the least-studied parts of the atmosphere. As well as carrying passengers aboard their vehicles, Virgin Galactic plan to change this by also flying experiments up to the mesosphere that might be used to probe it.

VSS Unity about to touch down, July 26th, 2018. Credit: Virgin Galactic

As with previous flights, today’s test flight was designed in part to gather additional data about conditions in the cabin during flight, but it also marks a significant step closer to the company starting commercial tourist flights, which are currently earmarked to commence in 2019, or possibly the end of 2018. Before that, however, the company will make at least one flight  with Unity’s motor fuelled for a full duration burn of 60 seconds. When that might be, and whether it might follow  directly on from this flight (which represented an 11 second longer engine burn than previous flights) or be worked up to, has yet to be stated.

When operational, VSS Unity will be joined by at least two more SpaceShipTwo vehicles, and – at some point in the next couple of years – an additional WhiteKnightTwo carrier vehicle, given the company are looking to operate flights out of Italy as well.

Continue reading “Space Sunday: an eclipse, a space ship, lasers and a birthday”

Space update special: the lake on Mars

An artist’s impression of Mars Express probing Mars using its MARSIS instrument superimposed on a radar cross-section of the southern polar layered deposits. The continuous white line at the top of the radar results above marks the beginning of the South Polar Layered Deposit; a layered accumulation of water ice and dust. The blue spots are areas of very high reflectivity and thought to be water. Credit D. Coero Borga/ESA / INAF

Whether or not liquid water exists on Mars has long been a source of study with regards to the Red Planet. There are many signs that the surface of Mars was once affected by free-flowing liquid – most likely water – in the planet’s ancient past. Curiosity, NASA’s Mars Science Laboratory rover, has confirmed the crater it has been exploring was home to several lakes during the early part of Mars’ history. What’s not clear is whether and how much of the remnants of that water still survives in liquid form today under the planet’s surface. Now a group of European scientists believe they have found direct evidence a sub-surface lake of liquid water on Mars.

The news comes via a paper published on Wednesday, July 25th in the Journal Science by a team of researchers involved in analysing the data from the European Space Agency’s Mars Express orbiter – something of a “forgotten mission” around Mars, given the volume of US missions on and orbiting the planet.

Mars Express arrived at Mars on December 25th, 2003. Since then, it has been quietly working away, observing Mars, gathering data about the planet’s atmosphere, surface and sub-surface, using a range of instruments including the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) package capable of “seeing” what lies under the surface of the planet. It is data from MARSIS which points to the presence of the subsurface lake.

An artist’s impression of Mars Express over Mars. The long booms (40m in length) extending from the vehicle are the deployed radar emitters for MARSIS. Credit: ESA

The story actually begins in 2007, when data from a MARSIS survey of a region near the Martian south pole revealed very strong differences in the radar returns (“echoes”) of two subsurface layers. On Earth, such a strong differentiation in returns typically tends to be the result of one of the layers being subsurface water. Analysis of the data from MARSIS initially suggested the “bright” return from the region on Mars might be caused by a layer of carbon dioxide ice. However, as further data was gathered on the region, researchers noticed something odd: the measurements of the layer kept changing over relatively short periods of time, rather than remaining relatively constant as might be expected from a body of subsurface ice.

Investigations of the apparent fluctuations in different radar returns of the same area revealed something unexpected: such was the volume of data point being collected by MARSIS, the software aboard Mars Express to initially process the returns was effectively averaging things out – giving the impression whatever the radar was encountering beneath the surface of Mars was somehow fluctuating: present in quantity during one pass, all but gone a few passes later, only to suddenly return in volume.

A composite image showing the south pole of Mars (r) and the region where the MARSIS radar reflections have been found (l). Credit: ESA

With their understanding of what was happening with the MARSIS processing, researchers were able to work out a means of compensating for it, and began a campaign of gathering data from the region, which ran for three years between mid-2012 mid mid-2015. It is the Earth-based analysis of this data over the last couple of years that has led to the conclusion that not only had MARSIS discovered something under the surface of Mars, but that it is very likely liquid water sitting under a covering of relatively cleat ice.

It is unclear if the body, some 20 km (12 mi) across and at least 2 metres deep and lying some 1.6 km (1 mile) beneath the surface, is actually an ice-covered body of water, or if it is an aquifer created by water filling interconnected pores in Martian rock beneath the ice.

However, given the extremely low temperatures on Mars, any water under the surface of the planet would require high concentrations of salt held in suspension within it, because salt helps reduce the temperature at which water freezes (a 20% solution lowers the freezing point of water to -16oC (-2oF), for example).  The data gathered by MARSIS is consistent with the liquid containing high concentrations of salts.

The discovery also has possible repercussions for the idea of Martian life.

For Life to get started, it needs three things: liquid water, an energy source such as minerals leeching into the water, and a biological seed. As noted at the top of this article, the evidence for water once having existed on Mars is strong. What’s more, NASA’s Curiosity rover has already found evidence for the second requirement – an energy source in the form of leeching minerals – was present at the time the planet had liquid water on its surface. So, if the third element – the biological seed – was available, then it is possible that microbial life may have started on Mars. Thus, there is the tantalising question of whether those Martian microbes might have followed the water into places like the south polar lake. However, we’re still a very, very long way from answering this particular question.

From what I think we have learned about this sub-glacial lake, the most likely analogue for this environment is the sub-glacial lake that was recently discovered in Canada… in which the lake itself is in contact with a deposit of salt, and so it is very, very salty. There are micro-organisms that are capable of surviving well below zero even without being in contact with water, and there are micro-organisms that can use the salt, presumably the salt in the water on Mars… for their metabolism.

– Roberto Orosei, MARSIS instrument co-investigator, and co-author of the lake study

Continue reading “Space update special: the lake on Mars”

Space Sunday: British space ports and some female space firsts

The United Kingdom is to gain a vertical launch space port in what might at first appear to be one of the most unlikely of locations: the A’Mhoine peninsula in Sutherland, Scotland, one of the most northerly points in the UK’s mainland.

The announcement that the UK Space Agency has selected the location, sitting between the Scottish coastal villages of Tongue and Durness, was made on July 16th, 2018. The new facility will be kick-started by a new £2 million fund established to boost vertical space port development across Britain.  In addition, the Highlands and Islands Enterprise (HIE), a Scottish government agency, will be given £2.5m from the UK government to develop the space port which could be up and running by the early 2020s.

In all, the HIE claims to have secured a total of £17.3m to develop the facility: £10 million through the HIE itself, and the remainder being put forward by “other sources”. It was selected over proposed sites at Unst in Shetland, and North Uist in the Western Isles.

The UK’s first vertical launch facilities will be developed on the north coast of Scotland and serve the polar orbit market. Credit: The Guardian

Given that most launch facilities try to be as close to the equator as possible in order to gain and additional “boost” from the Earth’s rotational speed of 1,600 km/h when launching a space vehicle, siting a space port so far north might at first sound odd. However, the facilities to be built at A’Mhoine, which will initially employ around 40 people on-site and provide supply chain jobs for up to 400 more, is not designed to place payloads in near-equatorial orbits. Instead, it will offer a means to reach the highly sought-after polar orbit, so-called because the payload circles the Earth pole-to-pole.

This is an increasingly valuable orbital path as a payload in such an orbit can, over time, pass over just about every point on the surface of the Earth, thanks to both its orbit and the Earth’s own rotation. Thus, it’s an ideal orbit in which to place Earth observing satellites, weather satellites, climate observing satellites – even communications relays.

A high northern latitude launch centre is also ideal for placing satellites in Sun-synchronous orbits, which allow their solar panels to remain in permanent sunlight. Such orbits are popular again with weather and climate observing payloads and also spy and ELINT (electronic intelligence) gathering satellites.

The primary launch vehicle for use at the new site has already been selected. It will be provided by a consortium of US aerospace firm Lockheed Martin and start-up business Orbex. They plan to use the New Zealand developed Electron rocket, designed by Rocket Labs.

Newquay Airport, Cornwall, could become one of a number of horizontal launch centres in the UK, and has announced a strategic partnership with Virgin Orbit to fly 747 / LauncherOne missions out of the airport, possibly starting in 2021. Credit: Cornwall Council

In addition, the UK government is also looking to develop so-called “horizontal spaceplane operations” centres across the UK. One of the prime contenders for this type of operation is “Spaceport Cornwall”, focused on Newquay Airport. Coinciding with the Scottish launch facility announcement, it was confirmed by Cornwall Council, operators of the airport, that Virgin Orbit and the airport’s management had entered into a strategic partnership which could see the airport become a base of operations for Virgin Orbit’s LauncherOne / 747 carrier aircraft combination.

If all goes according to plan, the first 747 / LauncherOne flight from UK soil could take place in 2021. The agreement itself marks the second such arrangement Virgin Orbit has entered into with a European country – as I reports in my previous Space Sunday update, the company has also entered into an agreement with the Taranto-Grottaglie airport in southern Italy to operate flights from that airport, alongside possible tourist flights by Virgin Galactic.

Virgin Orbit could be operating its LauncherOne rocket at carrier 747 out of Newquay Airport, Cornwall, from 2021. Credit: Virgin Orbit

The UK is a leading developer and constructor of satellites and other space systems, both on its own, through the likes of Surrey Satellite Technology, BAE Systems, ADS, and so on, and through the European Space Agency.

Name Sought for ExoMars Rover

The UK is the prime contractor for the European Mars rover, due to lift-off for the Red Planet in 2020 and set to commence operations there in 2021. A part of the European Space Agency’s ExoMars campaign, the rover is within a formal name. So, to correct this, on July 20th, 2018, the UK Space Agency launched a public competition to give the rover a name.

Entries are open to all EU citizens and limited to one entry per person. Entrants must offer a name for the rover and give a 150-word explanation of why they think it should be used. Entries must be submitted no later than 23:59pm BST on October 10th, 2018, and the winner and three guests will be able to tour the Airbus facility where the rover is being built.

The UK is the second largest European contributor to the ExoMars mission, behind Italy, having invested around £270 million into the programme. Airbus Defence and Space UK is leading the build of the rover, with the Mullard Space Science Laboratory at University College London, developing the rover’s major “eyes”, a high-resolution 3D camera which will be used to look at the terrain and rocks to try to detect signs of life. In addition, Leicester University and UK-based Teledyne e2v are involved in developing the Raman Spectrometer on the rover, while the Science and Technology Facilities Council’s Rutherford Appleton Laboratory will be responsible for processing the data it delivers.

British astronaut Tim Peake announces the launch of the competition to name the ExoMars rover, with a full-scale mock-up behind him. Credit:

Those wishing to enter the competition to name the rover can do so via the link above. The full terms and conditions for the project are available here. However, for those so inclined, “Marsy McMarsface” has already been ruled out as an option! (If you don’t get the reference see here – and I should probably note that Boaty McBoatface will sail with the Sir David Attenborough as well!)

Continue reading “Space Sunday: British space ports and some female space firsts”

Space Sunday: of rockets and planets

SpaceX Crew Dragon (l) and the Boeing CST-100 Starliner: Further delays could threaten US access to the ISS. Credit: SpaceX / Boeing

The first SpaceX Crew Dragon (aka Dragon 2) vehicle destined to fly in space has arrived in Florida ahead of its launch, due in August 2018. The capsule is intended to be part of an uncrewed first flight to test the vehicle’s flight test systems.

Prior its transfer to Kennedy Space Centre (KSC), the capsule and service module were the subject of extensive thermal vacuum chamber tests at NASA’s Plum Brook Station in Ohio. The world’s only facility capable of testing full-scale upper-stage launch vehicles and rocket engines under simulated high-altitude conditions, the chamber is a vital part of pre-launch testing – although by the date of the capsule’s arrival at KSC, the results of the Ohio testing had not been made public.

SpaceX’s first Crew Dragon spacecraft is prepared to undergo testing at the In-Space Propulsion Facility of NASA’s Plum Brook Station in Sandusky, Ohio on June 13th, 2018. Credit: SpaceX

No official date for the first Crew Dragon flight has been released, but SpaceX are pushing ahead with work to prepare the vehicle for launch, in anticipation of the flight being given the green light for August. The test flight should see the uncrewed test vehicle fly to the International Space Station (ISS), with a follow-up 14-day crewed test flight due to take place in late 2018 / early 2019.

The arrival of the Crew Dragon test article at KSC came at the same time as a further US government report raised concerns about both SpaceX and Boeing – the other company contracted to make crewed flights to / from the ISS using their CST-100 Starliner capsule – being able to meet the current schedule for commencing formal operations.

A July 11th, 2018, report from the independent Government Accountability Office (GAO) points out that if any significant issues arise with either / both vehicles prior to their formal certification, it could see one or other or both companies being unable to commence active crew launches within the anticipated time frames specified by NASA. Were this to be the case, America would effectively be without the means to send astronauts to the Space Station, as the current contract to fly US crew aboard Russian Soyuz vehicles expires in November 2019.

Under the original schedule, the Boeing CST-100 was to have been certified for crew operations in January 2019, and the Crew Dragon in February 2019. However, both these dates were recently revised: the CST-100 certification slipping to December 2019 and Crew Dragon’s to February 2020.

With crew rotations to the ISS lasting 6 months, this slippage – which moved the first official crewed flights of both CST-100 and Crew Dragon to several months after the Soyuz contract ends – were not seen as a significant issue. However, the GAO report warns that certification of both vehicles could slip to around August 2020 should difficulties with either / both vehicles be encountered as a result of the test flights (or other reasons). This would potentially see a nine-month gap open between the last of the planned US Soyuz flights and a commencement of CST-100 / Crew Dragon flights, more than the span of a crew rotation, with no contingency currently in place to allow continued US access to the ISS until either of the new vehicles is ready to fly.

A “Temperate” Exoplanet?

Ross 128 is a red dwarf star just 11 light-years away from our Sun that over the years has been a source of interest for astronomers. First catalogued in 1926, the star is too faint to be seen with the naked eye, but is classified an old disk star with a low abundance of elements other than hydrogen and helium. Like most red dwarf stars, Ross 128 is given to violent flare activity, although its extreme age makes such events a lot less frequent than “younger” red dwarfs.

In mid-2017, Ross 128 caused something of a stir when a mysterious burst of signals was recorded apparently coming from its general vicinity. Dubbed the “Weird!” signals, the series of unusual “transmissions” were received by the  Arecibo radio telescope, Puerto Rico on May 12th/13th, 2017.

The 2017 Weird! signal that seemed to come from Ross 128 (but has never been re-acquired). Credit: UPR Aricebo

At the time, the signals caused a lot of excitement and talk of “aliens” being involved – although no planets had actually been detected around Ross 128. As I reported in July 2017, after further study, it was determined that the most likely explanation for the signals was that they’d been accidentally picked up from satellites occupying the same part of the sky as Ross 128 at the time Aricebo happened to be listening; all attempts to re-acquire them by numerous radio telescoped failed to do so.

While there is no reason to change the view that the odd signals of May 2017 were from local satellites rather than originating with Ross 128, in November 2017 it was confirmed the star does in fact have a planet orbiting it.

Referred to as Ross 128 b, the planet was first detected in July 2017 by a team operating the High Accuracy Radial velocity Planet Searcher (HARPS) instrument at the La Silla Observatory in Chile. However, it was not until November of 2017 that the astronomers were able to confirm that had located the planet.  Since then, the planet has been the subject of indirect scrutiny to try to better determine its characteristics, and the results are interesting.

The HARPS data initially suggested the planet to be roughly around the size of Earth and orbiting in the star’s habitable zone. However, further characterisation of the planet – including whether or not it has an atmosphere – has been hampered by the fact that its orbit around its parent star means it doesn’t actually transit between Ross 128 and Earth.

An artist’s impression of Ross 128 b orbiting its parent star. Credit: ESO/M. Kornmesser

As this presents a barrier to analysing the planet directly by the effect it and its atmosphere (if it has one) has on light coming from its parent star, astronomers instead turned to studying Ross 128 itself in their attempts to better understand the potential nature of Ross 128 b.  In particular, a team led by Diogo Souto of Brazil’s Observatório Nacional used Sloan Digital Sky Survey‘s APOGEE spectroscopic instrument to measure the star’s near-infrared light to derive abundances of carbon, oxygen, magnesium, aluminium, potassium, calcium, titanium, and iron.

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