Category: Other Worlds and Tech

Space Sunday: total eclipse and exoplanet update

Posted on by Inara Pey
2016 total eclipse Credit: NASA Exploratorium webcast

On Monday, August 21st, the continental United States will experience its first total eclipse of the sun for 38 years (the last total eclipse visible from the USA having occurred in 1979). Providing the weather holds good along the path of the eclipse, an estimated 220 million people will be able to see the event – providing they take the proper precautions.

An eclipse is a periodic event, occurring when the Moon passes between the Sun and Earth and either fully or partially occults (blocks) the Sun’s light. This can happen only at new moon, when the Sun and the Moon are in conjunction as seen from Earth, in an alignment referred to as syzygy. There are actually four types of eclipse:

  • Partial – this occurs when the Sun and Moon are not exactly in line with the Earth, and so the Moon only partially obscures the Sun. Partial eclipses are virtually unnoticeable in terms of the sun’s brightness, as it takes well over 90% coverage to notice any darkening at all.
  • Annular – occurs when the Sun and Moon are exactly in line with the Earth, but because of the variations in the Earth’s distance from the Sun, and the variations in the Moon’s distance from the Earth, the apparent size of the Moon is smaller than that of the Sun. Hence the Sun appears as a very bright ring, or annulus, surrounding the dark disk of the Moon.
  • Total – occurs when the dark silhouette of the Moon completely obscures the intensely bright light of the Sun, allowing the much fainter solar corona to be visible. The complete coverage of the Sun’s disk by that of the moon – referred to as totality – occurs at its best only in a narrow track on the surface of Earth.
  • Hybrid (also called annular/total eclipse) – this shifts between a total and annular eclipse. At certain points on the surface of Earth, it appears as a total eclipse, whereas at other points it appears as annular. Hybrid eclipses are comparatively rare.

The last total eclipse took place in March 2016, and was visible from South/East Asia, North/West Australia, the Pacific and Indian oceans. The 2017 event will be visible in partial forms across every continent except Antarctica and Australia. However, the path of totality will only be visible across the continental United States.

Although totality slices through the U.S., partial phases of the eclipse touch on every continent except Antarctica and Australia. Credit: Michael Zeiler / The Great American Eclipse – click for full size

The path of totality will run from Oregon to South Carolina, as will be around 113 kilometres (70 miles) wide, offering people along it an unrivalled opportunity to view the eclipse  – weather permitting -, providing the right precautions are taken.

The most important aspect of viewing an eclipse “live” is never look directly at the Sun, even during the period of totality; you should at least use a solar filter or viewer. However, if you don’t have one or the other or any specialised kit, the best way to see the eclipse in the flesh is via pinhole projection. For those who are unable to see the eclipse first-hand, there are a wide variety of ways to watch the event on television or the Internet, including:

  • NASA Total Eclipse live stream is providing options to watch through NASA Edge, NASA TV, Ustream, YouTube and more. NASA’s Facebook page. These will show images of the eclipse, from 11 spacecraft, three aircraft and from more than 50 high-altitude balloons, and the astronauts on the International Space Station.
  • Slooh, the on-line community observatory, will run a webcast starting at 12:oo noon EDT (1600 GMT), as a part of a 3-day celebration of the eclipse.
  • The Virtual Telescope Project is hosting a free online observing session with views of the total solar eclipse beginning at 13:00 EDT (17:00 GMT).
  • The Eclipse Ballooning Project will be broadcasting live views of the eclipse from the edge of space via more than 57 cameras sent up on weather balloons.
  • CNN and Volvo will be providing a 360-degree view of the eclipse with 4K resolution from different locations along the eclipse path. The stream will also be viewable in virtual reality, which people can navigate by moving a phone or virtual reality headset. The live stream begins at 12:03 p.m. EDT (16:03 GMT).
  • ABC will air a two-hour special on the eclipse starting at 13:00 EDT (17:00 GMT). The broadcast will also be available on Facebook Live and YouTube

There are a number of terms common to eclipses which are worth mentioning for those who wish to follow the event, but are unfamiliar with the terminology. These include:

Eclipse Types (Moon and Sun not to scale). Credit: Cmglee
  • The umbra, within which the object in this case, the Moon) completely covers the light source (in this case, the Sun’s photosphere).
  • The antumbra, extending beyond the tip of the umbra, within which the object is completely in front of the light source but too small to completely cover it.
  • The penumbra, within which the object is only partially in front of the light source.
  • Photosphere, the shiny layer of gas you see when you look at the sun.
  • Chromosphere, a reddish gaseous layer immediately above the photosphere of the sun that will peak out during the eclipse.
  • Corona, the light streams that surround the sun.
  • First contact, the time when an eclipse starts.
  • Second contact, the time when the total eclipse starts.
  • Third contact, the time when the total eclipse ends.
  • Fourth contact, the time at which the eclipse ends.
  • Bailey’s beads, the shimmering of bright specks seen immediately before the moon is about to block the sun.
  • Diamond ring, the last bit of sunlight you see right before totality. It looks like one bright spot (the diamond) and the corona (the ring).

A total eclipse occurs when the observer is within the umbra (they are standing in the shadow cast by the Moon); an annular eclipse when the observer is within the antumbra, and a partial eclipse when the observer is within the penumbra.

As well as the passage of the Moon between the Earth and Sun, there are a number of Earthly effects to look for if you are in the path of totality, such as a the 360-degree sunset. This may also be accompanied by an “eclipse wind” as temperatures suddenly drop. And, of course, there is the rousing of nocturnal animals, fooled by the darkness, followed by a false dawn as the Moon moves away from between the Earth and the Sun, and an accompanying dawn chorus.

The period of totality lasts only a few minutes but offers a superb opportunity for observing the Sun and its corona – hence why NASA is using a chain of three aircraft to “chase” the eclipse as the Moon’s shadows travels at an average speed of 3,683 km/h (2,288 mph) west-to-east, enabling them to carry out an extended study of the corona.

The Moon’s shadow on Earth, as seen from the International Space Station on March 29th, 2006 as it passes over southern Turkey, Northern Cyprus and the Mediterranean Sea. Credit: NASA

As a point of historical interest, August 21st marks the 103rd anniversary of the 1914 total eclipse, which was seen from Scandinavia through to Turkey, the middle east and India. It was the subject of a number of expeditions being sent eastwards to the Baltic and Ukraine by Britain and other European nations with the intention of studying it – only for the conflagration of the First World War to erupt.

The war foiled attempts by a British expedition which intended to use the eclipse as a means to measure relativity; however, it did give rise to another mystery: whether or not a film of the eclipse apparently made in Sweden in 1914 is the real deal or not. If it is, it might be the oldest surviving footage of an eclipse.

If you are on the path of totality, and plan to view the eclipse, do please take the proper precautions and I hope the weather cooperates with you. I’ll be following things on-line.

Continue reading “Space Sunday: total eclipse and exoplanet update” →

Sansar and VR / AR in the press

Posted on by Inara Pey
AppliedVR: VR support for hospital patients. Credit: AppliedVR (see below)

This month has seen some interesting press pieces popping up concerning VR and Sansar since the opening of the Creator Beta. However, three in particular have so far caught my eye as they appeared, as they offer interesting perspectives and discussion points both on the Lab’s new platform and on VR and AR as a whole.

The first – and most recent, is Barely into Beta, Sansar is making social VR look good, by Alice Bonasio, which appeared in The Next Web on August 18th. The title caused some to question Sansar’s social capabilities, but the article itself was more about Sansar’s overall status and development, rather than zeroing directly into the medium of “social VR” per se. In this respect, it opens by clearly underlining the platform is still in its early days, and there is still much to be done, using a quote from Peter Gray, the Lab’s Director of Global Communications, to do so:

We wanted to make Sansar available to everyone as early as possible, and there are still a lot of features and capabilities that we’re excited to add to the platform soon, as well as many improvements to the current featureset.

Alice Bonasio: looking at Sansar

From here, Ms Bonasio makes the point that despite the lack of features and capabilities which will be needed to fulfil on its promise of being a social hub, it already looks good and offers a lot to see, much of which points to the platform’s potential.

The piece also delves into some of the technical and economic factors which set Sansar apart: such as Linden Lab’s partnerships with IKinema and Speech Graphics. The former is key to the Sansar avatars utilising Inverse Kinematics in an advanced way, and which are and will play a key role in the Sansar avatar’s development. The latter is key to synchronising facial animations automatically to match speech patterns, a capability key to many of the social interactions Linden Lab hope will be occurring within Sansar.

The article also touches on some of the key differences between Sansar and Second Life, the ability Linden Lab has to take fourteen years of running a virtual world to help shape the philosophy and approach it takes with Sansar. Passing – but important – mention is made of the Lab’s ability to self-finance Sansar; given the topsy-turvy situation with Altspace VR (which may have been saved from having to close), this is an important fact to keep in mind.

As noted above, the piece has received some feedback questioning the “social” element of Sansar at it stands at present, which given the broader thrust of the article might be considered a little out-of-context. However, it is fair to say that right now Sansar does currently lack elements which could be regarded as essential to supporting larger-scale social activities. Similarly, while social interactions are possible – as demonstrated through the daily meet-ups held “in-worlds” – it’s also fair to say these can be confusing and limiting for some. For example, undisciplined voice chat can mean that that multiple conversations in a single locale can overlay one another and become confusing to those not used to voice chat.

Hopefully these issues will be addressed, along with the provision of other social elements, and I’ll doubtless have more to say on them myself in the future 🙂 . In the meantime, this article provides a good summation of Sansar for the curious / those wishing to catch-up on things.

Samantha Cole examines VR’s role in conference calls

Over at The Fast Company, Samantha Cole uses Sansar to ask Will Virtual Reality Solve Your Conference Call Nightmares?

I’ll say up-front that I’m one of the non-believers that VR will become ubiquitous for business-style conference calls for a number of reasons, and its fair to say that Samantha Cole does a balanced job of presenting both sides of the argument – whilst also offering side pointers to those areas where VR is already showing benefits (and which I’d suggest Sansar could leverage).

Much has been made of VR’s abilities to add body language, hand movements, eye movement and contact – all vital elements in adding subliminal feedback / context to our day-to-day, face-to-face interactions to one another – to give more depth and meaning to tele- and video-style conferencing. In doing so, the likes of the telephone and “traditional” means of this type of conferencing have been somewhat “demonised”. Emphasis is laid on things like network latency, or the extra mental effort involved in reading into people’s words when you can only hear their voice or see their head / shoulders, as “limiting” such interactions.

But the truth is, we’ve been using the telephone for decades as a business tool. It’s fast and convenient, and as adults, we’re all pretty adept on picking-up on vocal nuances. We’re also, in a business context, far more prepared to communicate directly with colleagues; if there is something worrying / irksome within a work environment / business project, most of us are pretty willing to make thought known, be they over the ‘phone, face-to-face or via e-mail. So even with the faster, lighter, better VR technology we’re promised will be coming down the pipe, is it really any kind of “killer app” for business conferencing?

Eric Boyd, a professor of marketing at James Madison University points to emerging trends within the workplace as a whole being more a deciding factor here. Many companies have experimented with remote / home working over the past 2 or so decades, and the pendulum tends to swing back and forth. Right now, as the article points out, one of the first to enter the arena of remote working, IBM, is currently backing away from it. Thus, if working practices remain centralised, it’s hard to see VR overturning technologies already in place and supported by existing corporate infrastructure, no matter what the perceptions of their “limitations”. But for those organisations continuing to embrace remote working, VR could become a useful meeting tool.

Certainly there would seem to be far better uses VR could be put towards within a business environment: prototyping, training, simulations, and so on, which seem far more likely to drive its adoption by business and industry far more than the humble conference call. In this, Cole’s pointing to VR’s potential in training and simulation and in architecture is very salient; these are very much markets well suited to VR / AR / MR – perhaps more so that conference calls.

Amitt Mahajan – taking the temperature of the VR / AR market

Writing for Xconomy, Bernadette Tansey sits down with Amitt Mahajan, a Managing Partner at Presence Capital to take the temperature at VR / AR at mid-year., which also touches on the potential for both as business platforms / tools.

While Sansar is only mentioned in passing (together with the downs and ups of AltspaceVR), the article is interesting as it encompasses the viewpoint of a company investing in VR and AR start-ups with funding in the US $100,000-500,000 range – which is small when compared to the likes of the big players, but has allowed the company to bask some significant start-ups, including STRIVR, who are in the VR training a simulation field mentioned above.

The article opens which a rapid-fire overview of the VR / AR market – including its niche status at present, which could be said to be largely down to the limitations of the current hardware (or lack thereof in AR’s case, although that is beginning to change) rather than anything else. However, the meat of the piece is where Mahajan sees the technologies going over the next several years.

What’s interesting here is that within Presence Capital, they are moving away from consumer-focused VR endeavours and more towards business and business-to-business (B2B) / enterprise VR applications as well as for AR; he points to the likes of AppliedVR and their development of an immersive platform to help comfort patients  undergoing painful procedures, and also underlines VR’s application in training.

This year’s swing towards AR is also examined: Google, Apple and Facebook are all looking to develop AR platforms, and the discussion looks at these and at the questions of standards, formats, and enabling technologies. In this, Mahajan points somewhat towards the eventual merger of AR and VR to produce Mixed Reality, indirectly pointing to how AR – augmented reality – could actually become an enabler of VR (something the likes of Qualcomm are working towards with Android and their snapdragon chipset), simply because it will allow both to coexists as tools people can switch between according to needs.

All three article make for interesting reads, presenting a broad range of perspectives not just on Sansar (in the case of Alice Bonasio’s piece) but on VR and AR as whole.

AltspaceVR: the return

Posted on by Inara Pey
Courtesy of AltspaceVR

Following the announcement of its closure, Altspace VR is still open. I’d actually been holding off on this since Ciaran Laval first drew my attention to the news on August 16th, in case further details were forthcoming.

As I noted towards the end of July, the company had been planning to close shop on August 3rd. However, following the closure announcement, the company apparently received an outpouring of support – and with it, apparently the means to say open. This prompted an announcement on August 15th that the platform would be continuing:

It has been a roller coaster of a ride for our team and our community since we announced that AltspaceVR was coming to an end. We are elated to follow-up that dismal proclamation with some very good news: AltspaceVR is going to live on…

Thanks to that outpouring of support, we’re now deep in discussions with others who are passionate about AltspaceVR who want to guarantee that our virtual oasis stays open. We feel confident saying to our community that you don’t need to find another place to meet your friends in virtual reality. AltspaceVR is not closing down.

It’s not clear on exactly with whom the company has been in discussion – and that’s primarily the reason I’d been holding back on covering the news, lest further information was forthcoming on this matter. However, speculation following the announcement is the Oculus Rift co-founder Palmer Luckey may be involved in trying to maintain the company’s viability. He tweeted a poll following the news of the company’s intended shut-down, asking followers if he should step in. He then re-tweeted the news that Altspace VR would remain open, which further stoked speculation of his involvement.

AltspaceVR: avatar customisation

Techcrunch were perhaps the first news outlet to cover the evolving situation, with writer Lucas Matney noting:

It’s honestly unclear what to make of the sudden shutdown and un-shutdown announcements and whether they were just efforts to grab attention and put together a last-minute deal, but it is apparent that AltspaceVR still has their work cut out for them as they look to carve out a niche in a crowded social VR space that still has Facebook to compete with. 

He goes on to note that sources close to the company indicated that it had laid off several of its employees and had shut down the majority of its servers. However, the AltspaceVR clients all remain available for download, and the platform can be accessed and used (they’ll be hosting a solar eclipse event on Monday, August 21st as well).

Whatever the future of AltspaceVR, given its high-profile nature, the turmoil surrounding its survival highlights the risks associated with virtual reality when reliant on venture capital – and the benefits of being self-financed, as is the case with platforms such as Sansar – which is not so say there are no other risks involved in building a “social VR environment”.

High Fidelity reveal currency and IP protection roadmaps

Posted on by Inara Pey

In a pair of blog posts, Philip Rosedale of High Fidelity revealed the company’s plans to use blockchain technology as both a virtual worlds currency and for content protection.

The blockchain is described as “an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value” (Don Tapscott, Blockchain Revolution: How the Technology Behind Bitcoin Is Changing Money, Business, and the World). It allows transactions to be simultaneously anonymous and secure by maintaining a tamper-proof public ledger of value. While it is most recognised for its role in driving Bitcoin, the technology is seen by more than 40 of the world’s top financial institutions as a potential means to provide speedier and more secure currency transactions. However, the technology has the potential to have far wider application.

To understand the basics of the blockchain, think of a database duplicated across the Internet, allowing any part of it to be updated by anyone at any time, and the updates being immediately available across all the duplicates of the database. Information held on a blockchain exists as a shared — and continually reconciled — database existing across multiple nodes. The decentralised blockchain network automatically checks with itself every ten minutes, reconciling every transaction, with each group of transactions checked referred to as a”block”. Within the network, nodes all operate as “administrators” of the entire network, and are encouraged to join it through what is (mistakenly) referred to as “mining”  – competing to “win” currency exchanges, sometimes for financial reward to the node’s operators (High Fidelity indicate that node operators will not gain directly from “mining” activities, but will instead be paid in HFCs for their computing resources used by the network).

Centralised, distributed and de-centralised networks – blockchains utilised decentralised networks

The key points to all this is that the blockchain is both openly transparent – the data is embedded in the network as a whole, not in any single point, and is by definition “public”. The lack of any centralisation also means it cannot be easily hacked – doing so would require huge amounts of computing power; nor is there a single point of data which can be corrupted or reliant on a single point of management for its continued existence – as High Fidelity point out, this means that the service can continue, even if High Fidelity does not. Thus, blockchain networks are considered both highly robust and very secure.

An estimated 700 Bitcoin-like crypto-currencies are already thought to be in operation, although the potential use of blockchains goes far, far beyond this (identity management, data management, record-keeping, stock broking, etc., etc.).

High Fidelity plans, over the coming months, to deploy their own blockchain network which will support both a new crypto-currency, the HFC (presumably “High Fidelity Currency”), which will ultimately operate independently of High Fidelity’s control. In addition, the system will provide a mechanism to protect intellectual property by embedding object certification affirming item ownership into the blockchain. This means that creators of original digital content. As High Fidelity explain:

Digital certificates issued by the High Fidelity marketplace (and likely other marketplaces choosing to use HFC) will serve a similar function as patents or trademarks — creators will register their works to get the initial certificates, and these certificates will be given out only for work that is not infringing on other or earlier works…. Once granted, these durable certificates cannot be revoked and can then be attached to purchases on the blockchain to prove the origin of goods. The absence of an accompanying digital certificate and blockchain entry will make digital forgery more obvious and impactful than in the real world — for example, server operators may choose not to host content without certificates and end-users may choose not to ‘see’ content according to it’s certificate status.

This approach could provide an extremely durable and trusted means of sharing digital content, one which is more durable than other approaches to digital rights management, for the same reasons as the blockchain offers security, transparency and robustness to operating a crypto-currency.

That the HFC blockchain is designed to operate independently of High Fidelity means that it can become self-sustaining, providing a currency environment that can be traded with other crypto-currencies and which can be exchanged for fiat currency through multiple exchanges.

The two blog posts – Roadmap Currency and Content Protection and Roadmap: Protecting Intellectual Property in Virtual Worlds – are very much companion pieces to be read in the order given. The first provides an overview of the HFC blockchain system and currency management, including how High Fidelity hope to establish a stable exchange rate mechanism without running into the issues of speculative dabbling in the system, inflated ICOs, etc., and on the use of digital wallets and personal security. It also outlines the certification mechanism for content protection, which the second article takes a deeper dive into, explaining how the relative strengthen of a blockchain approach as very quickly sketched out above could be used in protecting creator’s IP and controlling how their products / creations are used.

The decentralised approach to currency and digital rights management is something that has been pointed to numerous times during High Fidelity’s development, but this is the first time the plans have been more fully fleshed out and defined in writing. It’s an ambitious approach, one likely to stir debate and discussion – particularly given the current situation regarding the Decentraland / Ethereum and the risk of speculation around ICOs (again, something High Fidelity hope to avoid).

it’s also one which again points to High Fidelity’s founders looking far more towards more of an “open metaverse” approach to virtual environments and goods than others might be considering.

Space Sunday: Voyager at 40

Posted on by Inara Pey
Voyager: 40 years on. Credit: NASA

August 20th 2017 marks the 40th anniversary of the launch of Voyager 2, which with its sister craft Voyager 1 (launched on September 5th, 1977) are humanity’s furthest-flown operational space vehicles, with Voyager 1 being the most distant human made object from Earth, at some 140 AU (AU= astronomical unit, the average distance between the Earth and the Sun; 140 AU equates to about 20.9 billion kilometres / 13 billion miles).

Despite being so far away from Earth, both craft are still sending data back to Earth as they fly through the interstellar medium in the far reaches of the solar system (the Pioneer 10 and Pioneer 11 craft which pre-date the Voyager programme by some 5 years, ceased transmissions to Earth in January 2003 and September 1995 respectively, although Pioneer 10 is the second most distant human made object from Earth after Voyager 1).

The Voyager programme stands as one of the most remarkable missions of early space exploration. Originally, the two vehicles were to be part of NASA’s Mariner programme, and were at first designated Mariner 11 and Mariner 12 respectively. The initial Mariner missions – 1 through 10 – were focused on studying the interplanetary medium and  Mars, Venus and Mercury (Mariner 10 being the first space vehicle to fly by two planets beyond Earth – Venus and Mercury – in 1974). Mariner 11 and Mariner 12 would have been an expansion of the programme, intended to perform flybys of Jupiter and Saturn.

A drawing of the Voyager vehicles. Credit: NASA/JPL (click for full size)

However, in the late 1960s Gary Flandro, an aerospace engineer at the Jet Propulsion Laboratory (JPL) in California noted that in the late 1970s, the outer planets would be entering a period of orbital alignment which occurs once every 175 years and which could be used to throw a series of probes out from Earth, which could then use the gravities of the worlds they encountered to “slingshot” them on to other targets. This led to the idea of a “Grand Tour” mission: sending pairs of probes which could use these gravity assists to fly by Jupiter, Saturn, Uranus, Neptune and Pluto in various combinations.

Funding limitations eventually brought an end to the “Grand Tour” idea, but the planetary alignment was too good an opportunity to miss, and so elements of the idea were folded into the Voyager Programme, which would utilise Mariner 11 and Mariner 12. However, as the mission scope required some significant changes to the vehicles from the basic Mariner design, they were re-designated as Voyager class craft.

(As an aside, the Mariner class is the longest-lived of NASA’s space probe designs; as well as the ten missions of the 1960s and 1970s which carried the design’s name,  the Mariner baseline vehicle – somewhat enlarged – was used for the Viking 1 and Viking 2 orbiter missions to Mars, and formed the basis of the Magellan probe (1989-1994)  to Venus and the Galileo vehicle (1989-2003) which explored Jupiter. And uprated and updated baseline Mariner vehicle, designated “Mariner Mark II”, formed the basis of the Cassini vehicle, now in the terminal phase of its 13-year study of Saturn and its moons.)

Each of the Voyager mission vehicles is powered by  three plutonium-238 MHW-RTG radioisotope thermoelectric generators (RTGs), which provided approximately 470 W at 30 volts DC when the spacecraft was launched. By 2011, both the decay of the plutonium and associated degradation of the thermocouples that convert heat into electricity has reduced this power output by some 57%, and is continuing at a rate of about 4 watts per year.

To compensate for the loss, various instruments on each of the vehicles have had to be turned off over the years. Voyager 2’s scan platform and the six instruments it supports, including the vehicle’s two camera systems, was powered-down in 1998. While the platform on Voyager 1 remains operational, all but one of the instruments it supports – the ultraviolet spectrometer (UVS) – have also been powered down. In addition, gyro operations ended in 2016 for Voyager 2 and will end in 2017 for Voyager 1. These allow(ed) the craft to rotate through 360 degrees six times per year to measure their own magnetic field, which could then be subtracted from the magnetometer science data to gain  accurate data on the magnetic fields of the space each vehicle is passing through.

However, despite the loss of capabilities, both Voyager 1 and Voyager 2 retain enough power to operate the instruments required for the current phase of their mission – measuring the interstellar medium and reporting findings back to Earth. This phase of the mission, officially called the Voyager Interstellar Mission, essentially commenced in 1989 as Voyager 2 completed its flyby of Neptune, when the missions as a whole was already into their 12th year.

A plume rises 160 km (100 mi) above Loki Patera, the largest volcanic depression on Io, captured in March 1979 by Voyager 1. Credit: NASA/JPL

Voyager 2 was launched on August 20th, 1977. Of the two vehicles, it was tasked with the longer of the planned interplanetary missions, with the aim of flying by Jupiter, Saturn, Uranus and Neptune. However, the latter two were seen as “optional”, and dependent upon the success of Voyager 1.

This was because scientists wanted the opportunity to look at Saturn’s moon Titan. But doing so would mean the Voyager craft doing so would have to fly a trajectory which would leave it unable to use Saturn’s gravity to swing it on towards an encounter with Uranus. Instead, it would head directly towards interstellar space.

So it was decided that Voyager 1, which although launched after Voyager 2 would be able to travel faster, would attempt the Titan flyby. If it failed for any reason, Voyager 2 could be re-tasked to perform the fly-past, although that would also mean no encounters with Uranus or Neptune. In the end, Voyager 1 was successful, and Voyager 2 was free to complete its surveys of all four gas giants.

Along the way, both missions revolutionised our understanding of the gas giant planets and revealed much that hadn’t been expected, such as discovering the first active volcanoes beyond Earth, with nine eruptions imaged on Io as the vehicles swept past Jupiter. The Voyager missions were also the first to find evidence that Jupiter’s moon Europa might harbour a subsurface liquid water ocean and to return the first images of Jupiter’s tenuous and almost invisible ring system. Voyager 1 was responsible for the first detailed examination of Titan’s dense, nitrogen-rich atmosphere, and Voyager 2 for the discovery of giant ice geysers erupting on Neptune’s largest moon, Triton. In addition, both of the Voyager vehicles added to our catalogues of moons in orbit around Jupiter and Saturn, and probed the mysteries of both planet’s atmospheres, whilst Voyager 2 presented us with our first images of mysterious Uranus and Neptune – and thus far remains the only vehicle from Earth to have visited these two worlds.

This is the last full planet image captured of Neptune. Taken by Voyager 2 on August 21st, 1989, from a distance of 7 million km (4.4. million mi). A true colour image white balanced to reveal the planet under typical Earth lighting conditions, it shows Neptune’s “Great Dark Spot” and surrounding streaks of lighter coloured clouds, all of which persisted through the period of Voyager 2’s flyby. More recent Hubble Space Telescope images suggest the “Great Dark Spot”, initially thought to be a possible cloud / storm formation, similar to Jupiter’s Great Red Spot, has vanished, leading to speculation that it may have actually been a “hole” in a  layer of Neptune’s layered clouds. Credit: NASA/JPL

The flyby of Neptune also sealed Voyager 2’s future. Scientists were keen to use the flyby of the planet to take a look at Triton, Neptune’s largest moon. However, because Triton’s orbit around Neptune is tilted significantly with respect to the plane of the ecliptic, Voyager 2’s course to Neptune  had to be adjusted by way of a gravitational assist from Uranus and a number of mid-course corrections both before and after that encounter, so that on Reaching Neptune, it would pass over the north pole, allowing it to bent “bent” down onto an intercept with Triton while the Moon was at  apoapsis – the point furthest from Neptune in its orbit – and well below the plane of the ecliptic. As a result, Voyager 2 passed over Triton’s north pole 24 hours after its closest approach to Neptune, its course now pointing it towards “southern” edge of the solar system.

Continue reading “Space Sunday: Voyager at 40” →

Space Sunday: Curiosity’s 5th, Proxima b and WASP-121b

Posted on by Inara Pey

On August 6th 2016, NASA delivered the Mars Science Laboratory (MSL) to the surface of Mars in what was called the “seven minutes of terror” – the period when the mission slammed into the tenuous Martian atmosphere to begin deceleration and a descent to the surface of the planet which culminated in the Curiosity rover being winched down gently from a hovering “sky crane” and then lowered until its wheels made firm contact with the ground.

The “seven minutes of terror” actually had a double meaning. Not only did it represent the time MSL would smash into Mars’ atmosphere and attempt its seemingly crazy landing, at the time of the event, the distance between Earth and Mars meant it took seven minutes to be returned to mission control from the red planet. Thus, even as the initial telemetry indicating the craft was entering the upper reaches of Mars’ tenuous atmosphere was being received, mission controls knew that in reality, the landing had either succeeded or failed.

Obviously, the attempt succeeded. Everything worked flawlessly, and Curiosity was delivered to the surface of Mars at 05:17 GMT on August 6th, 2012 (01:17, August 6th EDT, 22:17 PDT, August 5th). In the five years since that time, it is helped revolutionise our understanding of that enigmatic world – as well as adding somewhat to its mystery.

To call the mission a success is not an exaggeration; within weeks of its arrival inside the 154 kilometre (96 mile) wide Gale Crater, Curiosity was examining an ancient riverbed en route to a region of the crater dubbed “Yellowknife Bay”. It was there the rover made its first bombshell discovery: analysis of the area showed that billions of years ago it was home for the ideal conditions to potentially kick-start microbial life. It was, in essence, the achievement of mission’s primary goal: to identify if Mars may have once harboured the kind of conditions which might have given rise to life.

This 360-degree view was acquired on August 6th, 2016, by Curiosity’s Mastcam as the rover neared the “Murray Buttes” on lower “Mount Sharp”. The dark, flat-topped mesa seen to the left of the rover’s arm is about 15 metres (50 ft) high and about 61.5 metres (200 ft) long. Credit: NASA/JPL / MSSS

For the first year following its arrival on Mars, Curiosity continued to survey the regions relatively close to its landing zone, finding more evidence of a benign ancient environment. Then it started out on the next phase of its mission: the long traverse towards the massive bulk of “Mount Sharp” – officially called Aeolis Mons. A huge mound of rock deposited against the crater’s central impact peak, “Mount Sharp” rises from the crater floor to an altitude of some 5.5 km (3 mi), and imagining from orbit strongly suggested its formation was due, at least in part, to the presence of water in the crater at some point in Mars’ past.

The 8 km (5 mi) trip took the rover a year to complete, in part due to its relatively slow speed, in part due to the fact is had to travel a good way along the base of “Mount Sharp” to reach a point where it could commence an ascent up the slope; but mostly because there were a number of points of interest along the way where the mission scientists  wanted to have a look around, investigate and sample.

Mount Sharp as seen from Curiosity, on January 24th, 2017. The light grey banding befpre the sandy coloured slopes is the clay unit the rover will reach in about 2 years. In front of it is the “Vera Rubin Ridge”, the next location for study by the rover. Credit: NASA/JPL / MSSS

For the last three years, the rover has been slowly making its way up “Mount Sharp”, climbing around 180 metres (600ft) vertically above the surrounding crater floor and visiting numerous points of interest – such as “Pahrump Hills”, the mixed terrain where “Mount Sharp” merges with the crater floor. Along the way, Curiosity has both confirmed that “Mount Sharp” was most likely the result of sedimentary deposits laid down during several periods of flooding in the crater before the water finally receded and wind action took over, sculpting the mound into its present shape down through the millennia.

The lakes within Gale crater may have actually been relatively short-lived, perhaps lasting just 1,000 years at a time, but Curiosity has shown that even during the dry inter-lake periods, water was very much a feature of Gale Crater, finding evidence of compressed water channels within the layers of rock which sit naturally exposed on “Mount Sharp’s” flanks.

In December 2014, NASA issued a report on how “Mount Sharp” was likely formed. On the left, the repeated depositing of alluvial and wind-blown matter (light brown) around a series of central lakes which formed in Gale Crater, where material was deposited by water and more heavily compressed due the weight of successive lakes (dark brown). On the right, once the water had fully receded / vanished from the crater, wind action took hold, eroding the original alluvial / windblown deposits around the “dry” perimeter of the crater more rapidly than the densely compacted mudstone layers of the successive lake beds, thus forming “Mount Sharp”

Alongside the sedimentary layering of the mudstone comprising “Mount Sharp” and the compressed and long-dry water channels, a further sign that the region was once water rich comes in the form of the mineral hematite, which Curiosity has found on numerous occasions. Right now, the rover is making its way towards a feature dubbed “Vera Rubin Ridge” which orbital analysis shows to be rich in this iron-bearing mineral which requires liquid water to form. Beyond that is a clay-rich unit separating the hematite rich ridge from an area which show strong evidence for sulphates. These are also indicative of water having once been present, albeit less abundantly than along “Vera Rubin Ridge”, and thus hinting at a change in the local environment. Currently, Curiosity is expected to reach this area in about two years’ time, after studying “Vera Rubin Ridge” and the clay unit along the way.

Selfies from Mars: how Curiosity has weathered the dust on Mars over five years – the dates are given as Sols – Martian days, top left and the locations where the pictures were taken. Credit: NASA/JPL

Throughout the last five years, Curiosity has remained relatively healthy. There has been the odd unexpected glitch with the on-board computers, all of which have been successfully overcome. There has been some damage to the rover’s aluminium wheels. This did give rise to concern at the time it was noted, resulting in a traverse across rough terrain being abandoned in favour of a more circuitous and less demanding route up onto “Mount Sharp”. But overall, the wheels remain in reasonably sound condition.

The one major cause for concern at present lies with Curiosity’s drill mechanism. Trouble with this first began when vibrations from the drill percussive mechanism was noted to be having a negative impact on the rover’s robot arm.

More recently – since December 2016, in fact – all use of the drill has ceased, limiting Curiosity’s sample gathering capabilities. This has been due to an issue with the drill feed motor, which extends the drill head away from the robot arm during normal drilling operations, preventing the arm physically coming into contact with targets. Attempt to rectify the problem have so far been unsuccessful, so engineers are loot at ways to manoeuvre the rover’s arm and place the drill bit in contact with sample targets, avoiding the need to use the feed motor.

So with five years on Mars under its belt, and barring no major unforeseen incidents, Curiosity will continue its mission through the next five years, further enhancing our knowledge of Mars.

Continue reading “Space Sunday: Curiosity’s 5th, Proxima b and WASP-121b” →