Tag: New Horizons

NASA and the Applied Physics Laboratory (APL) at John Hopkins University kept their promise a little earlier than expected.

With the resumption of image and data transmissions from New Horizons, at the start of September, they had indicated that Fridays would henceforth, and for the course of the next 12 months, be known as Pluto Friday, the day on which the latest raw images from the mission to that distant tiny world and its companions would be released.

However, the first set of images came a little sooner than advertised: on Thursday, September 10th, and they continue to show two tiny worlds which continue to astound and have planetary scientists rethinking much about their understanding of dwarf planets.

“Pluto is showing us a diversity of landforms and complexity of process that rival anything we’ve seen in the solar system,” New Horizons’ principal investigator Alan Stern, from the Southwest Research Institute in Colorado, said in a statement. “If an artist had painted this Pluto before our flyby, I probably would have called it over the top — but that’s what is actually there.”

The images render details as small as 400 metres / 440 yards per pixel on the surface of Pluto, and reveal features that have scientists agog with excitement; so much so that at a NASA press conference, the images were summarised thus, “it’s complicated!”

In them, we can see a rich complexity of features: nitrogen ice flows which have apparently oozed (and might still be slowly oozing) out of mountain ranges and across broad plains; mountain ranges which are themselves reminiscent of chaotic regions on Mars and Jupiter’s Europa; complex valley systems which might have been carved by the action of material flowing across the planet; and even – perhaps most curiously of all –  what seem to be wind-blown fields of dunes.

What is also particularly striking about these images of Pluto is the way that they reveal some of the oldest  (geologically speaking) regions yet seen on the planet sitting right alongside what are the youngest locations on the planet, adding further emphasis to the idea that Pluto has been, and might still be, an active world.

But what about those dunes mentioned above? If they are indeed what the images released on September 10th suggest, Pluto has once again served up a surprise.

“Seeing dunes on Pluto, if that is what they are would be completely wild!” William McKinnon from the mission’s Geology, Geophysics and Imaging (GGI) team, said, “because Pluto’s atmosphere today is so thin. So either Pluto had a thicker atmosphere in the past, or some process we haven’t figured out is at work. It’s a head-scratcher!”

More is also being discovered about Pluto’s atmosphere, which is also proving to be a lot more complex than had originally been thought, having many more layers within its thin haze than had been thought. However, these layers of haze have allowed the science team to glimpse surface features which might otherwise have remained unseen as sunlight caught by the haze over the terminator – the divide between the day and night sides of the planet – cast a soft glow over part of Pluto’s night side. When enhanced through careful processing, this glow could be used to reveal what lay below.

Continue reading “Space Sunday: of Pluto, Mars and crowdfunding space outreach” →

It’s been a little quiet on the new images front where the New Horizons mission is concerned. The spacecraft, which performed the first ever flyby of Pluto and Charon in July, gathered a wealth of data, around 95% of which has remained aboard the spacecraft awaiting transmission back to Earth.

There have been a number of reasons this has been the case. First off, for the period following the close encounter, New Horizons continued to gather data and images of the Pluto-Charon system. Such is the design of the vehicle that while doing this, it couldn’t actually transmit information back to Earth. Also, once the data had been gathered it required sorting and prioritising ready for transmission back to Earth, and this again took time to do.

However, on Saturday, September 5th, New Horizons oriented itself to make contact with the Deep Space Network (DSN) operated by NASA for what was the start of a year-long “intensive” download of the 10 gigabits of data gathered by the craft, starting with information the science team regard as the highest priority data sets.

The reason the transfer will take so long is not only because the enormous distance between New Horizons and Earth, which takes radio signals moving at the speed of light over 4.5 hours to cross (a time which is slowly increasing), but also because the rate at which the data can be transmitted is limited.

Currently, the nuclear “battery” powering New Horizons can only produce around 2-10 watts of electrical power, which has to keep all of the various electrical systems warm and running. So to conserve power, the vehicle only transmits data at between 2-4 kbps. To put that in perspective, it would take you about 2 hours to download a single photo from your cellphone to your computer at those speeds.

Discussing the start of the extended data download from New Horizons, Alan Stern, the mission’s Principal Investigator, said, “this is what we came for – these images, spectra and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time.”

He continued, “and what’s coming is not just the remaining 95 percent of the data that’s still aboard the spacecraft – it’s the best datasets, the highest-resolution images and spectra, the most important atmospheric datasets, and more. It’s a treasure trove.”

To mark the receipt of data and images, NASA / JPL and John Hopkins’ APL have designated Friday as Pluto Friday, when they’ll be publishing that latest images, unprocessed, received from the spacecraft the previous week. The images will be available on the LORRI image catalogue, operated by JHU / APL, starting on Friday, September 11th, 2015.

In the meantime, here’s an animated video from NASA, showing the Pluto flyby, just to whet appetites.

Mars’ Atmosphere: Where did It Go?

One of the many mysteries of Mars is what happened to its atmosphere. All of the evidence gathered over the years about the Red Planet is that it once had an atmosphere dense enough to support free-flowing liquid water, and that potentially as much of 20% of the planet’s surface may have been submerged.

So what happened? There are a number of theories. One of these is that over time, the action of the solar wind, combined with Mars’ relatively weak gravity, effectively “scooped” much of the atmosphere away into space.   Measurements of heavy and light carbon ratios in the present day atmosphere lend considerable weight to this theory.

Another idea is that carbon dioxide, the major constituent of Mars’ atmosphere may have been “sequestered” – that is, “pulled” out of the atmosphere to be stored in rocks and subsurface deposits by various chemical reactions, forming carbonate minerals in the process.

This theory was given its own boost when a region of Mars called Nili Fossae, approximately as big as the US state of Arizona, was found to have huge deposits of carbonates (more recently this region has been of interest to scientists due to the discovery of impact glass, helping to mark the region as a candidate target for the Mars 2020 rover mission).

Continue reading “Space Sunday: Pluto calls, Mars mystifies, Starliner prepares” →

New Horizons is continuing outbound from the Pluto-Charon system, its primary mission  complete. A new phase of the mission has now begun: returning all the data gathered safely to Earth; a process that is going to take an estimated 16 months to complete. Even so, and as indicated in my last report, what has already been received has been enough to turn much of planetary science on its head.

During a mission briefing on July 24th, 2015, Alan Stern, the New Horizons principal investigator and members of the science team provided a further update on the mission, and revealed some of the more stunning images captured by the spacecraft during the close approach phase of the mission. One of the most striking of these was a picture snapped by New Horizons just seven hours after close approach, when it was already 2 million kilometres (1.2 million miles) from Pluto.

The image shows the dark disc of Pluto’s night side (which will not see the light of the Sun for another 20 years), surrounded by a halo of atmosphere, 130 kilometres (80 miles) thick, backlit by the distant Sun. Within the atmosphere sit two bands of thick haze, one around 50 kilometres (30 miles) altitude and the second at around 80 kilometres (50 miles) altitude.

These bands of haze are believed to be the result of ultraviolet sunlight striking the upper reaches of Pluto’s atmosphere, breaking apart the methane gas there, giving rise to more complex hydrocarbon gases such as ethylene and acetylene. These heavier gases then descend into the colder regions of Pluto’s atmosphere, condensing as ice particles, which are seen by New Horizon’s instruments as the bands of haze.

The ice particles are further acted upon by ultraviolet sunlight so that tholins are formed. Tholins are large complex organic aerosols thought to contain some of the chemical precursors of life. These gradually fall out of the atmosphere to mix with hydrocarbons on Pluto’s surface, giving it the distinctive colouring we see in images like those given below.

The July 24th briefing also revealed some of the most detailed images of Pluto’s sunlit side yet published, starting with the true colour image shown above. This shows Pluto in twice the level of detail as the July 13th image published by NASA, revealing surface features as small as two kilometres across (the ultra-high resolution images LORRI has captured will eventually reveal surface features as small as 50 metres across). Featured prominently and unmistakably in the image is Pluto’s light-coloured “heart”, informally named the “Tombaugh Regio” in honour of Pluto’s discoverer, Clyde Tombaugh.

This huge region is divided into two parts, defined by the two “lobes” of the heart. On the left (west side) is the relatively smooth expanse of the “Sputnik Planum”, roughly the size of Texas.The is largely composed of a thick layer of nitrogen, methane and carbon monoxide ice. That it is almost completely without craters suggests it is much younger than the rest of Pluto’s visible surface; but how it formed has yet to be determined.

The right side of the “heart” is also brightly-coloured, indicating the presence of ices similar in nature to those in “Sputnik Planum”, but it also shows a much rougher terrain as well. Further bright, icy material also extends from the “point” of the “heart” into the southern polar regions of Pluto, again mixing with rougher terrain.

While it is not clear what actually gave rise to the icy expanse of “Sputnik Planum”, it is not believed the same mechanism is responsible for the ice in either eastern lobe or which extends southwards from the “heart”. These are believed to be the result of material from “Sputnik Planum” being carried into these areas, where it is gradually “painting over” surface features there.

Continue reading “Space update: Pluto, Mars, and Earth’s big cousin” →