Space Sunday: Pluto calls, Mars mystifies, Starliner prepares

new-horizonIt’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.

NASA Deep Space Network facility near Canberra, Australia
NASA Deep Space Network (DSN)  is a set of three communications facilities operated by NASA in Spain, Australia (shown above) and California. They are tasked with maintaining communications with NASA’s deep space and planetary missions. Located roughly 120-degrees apart around the Earth, the three facilities can between them maintain a constant radio observation on any spacecraft under their command as the Earth rotates.

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.

An artist's impression of what a wet Mars may have looked like, based on the ratio of deuterium contained within the Martian polar caps
An artist’s impression of what a wet Mars may have looked like, based on the ratio of deuterium contained within the Martian polar caps

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).

Nili Fossae is a region of Mars which is of significant interest o scientists and geologists, not only for this mineral deposits, but also because of its striking, fractured terrain, possibly split by whatever caused the nearby Isidis impact basin, thought to be the last such massive impact basin formed on the planet, probably around 3.9 billion years ago
Nili Fossae is a region of Mars of significant interest to scientists and geologists not only for this mineral deposits, but also because of its striking, fractured terrain, thought to have been created as the same time as the massive and nearby Isidis impact basin, which is itself thought to be the last such massive impact basin formed on the planet, probably around 3.9 billion years ago (image: ESA)

However, a recent study of data on Nili Fossae gathered from a number of instruments flown aboard various space vehicles over the last two decades suggests the total amount of carbonates contained in the region amounts to around twice a much carbon as found in the present day Martian atmosphere.

The study of Nili Fossae used spectrograph data gathered from several instruments flown on various craft in Mars orbit, including the CRISM instrument on NASA’s Mars Reconnaissance Orbiter, in which carbonates in the region are indicated by the green colouring
The study of Nili Fossae used spectrograph data gathered from several instruments flown on various craft in Mars orbit, including the CRISM instrument on NASA’s Mars Reconnaissance Orbiter, in which carbonates in the region are indicated by the green colouring (image: NASA / JPL)

While that sounds a lot, it’s actually not enough to account for sequestering having played a major role in the disappearance of Mars’ atmosphere.

In fact, the study shows that if all of the carbonate deposits mapped across the surface of Mars were combined, they still wouldn’t be enough to account for the kind of warm, dense atmosphere that has been theorised as existing when the various water features were forming on Mars. Rather, it would actually take around 35 regions the size of Nili Fossae to achieve this – and these haven’t been found.

So it would seem that the study, carried out by Bethany Ehlmann of the California Institute of Technology and NASA’s JPL and Christopher Edwards, a former Caltech researcher now with the U.S. Geological Survey, may have pushed the sequestration theory well off to one side when trying to account for the loss of Mars’ atmosphere. However, in doing so, it also raises another conundrum: was the ancient atmosphere on Mars necessarily as warm for as long as has been theorised?

“Maybe the atmosphere wasn’t so thick by the time of valley network formation,” Edwards said. “Instead of Mars [being] wet and warm, maybe it was cold and wet with an atmosphere that had already thinned. How warm would it need to have been for the valleys to form? Not very. In most locations, you could have had snow and ice instead of rain. You just have to nudge above the freezing point to get water to thaw and flow occasionally, and that doesn’t require very much atmosphere.”

If this is the case, it could have interesting implications for climate and other models relating to early Mars.

Boeing Name their Crew Vehicle

Following the retirement of the space shuttle fleet, NASA has been left without the means to launch crews into space. In order to allow the space agency to focus on developing a new launch capability theoretically capable of taking humans back to the Moon and / or to Mars, the job of developed vehicles capable to launching crews to the International Space Station has been contracted-out to SpaceX and Boeing, in what is known as the Commercial Crew Programme.

SpaceX have already named their vehicle: Dragon 2, it being an evolution of their current, unmanned Dragon spacecraft used to ferry supplies up to the space station, but Boeing have simply referred to their vehicle as the CST-100 (“Commercial Space Transport”).

All that changed on Friday, September 4th, 2015, when Boeing announce their vehicle will be called the CST-100 Starliner.

CST-100 Starliner will be used to launch up to 6 people on flights to the International Space Station and return up to 6 to Earth
CST-100 Starliner will be used to launch up to 6 people on flights to the International Space Station and return up to 6 to Earth

The name is intended to reflect the company’s long history of aerospace development (it will celebrate its 100th anniversary in 2016) by reflecting the Dreamliner title applied to their 787 airliner, and also acknowledge future generations of crewed space vehicles which will hopefully follow it.

Boeing announced the new name at a grand opening ceremony for its Commercial Crew and Cargo Processing Facility at NASA’s Kennedy Space Centre. The building was previously one of three Orbiter Processing Facilities used to refurbish the space shuttle vehicles between their flights, and will be used by Boeing to assemble and test the CST-100 Starliner spacecraft before launching them to the ISS atop Atlas 5 rockets.

The CST-100 Starliner will be prepared for flight using a refitted Orbiter Processing Facility, once used to refurbish and prepare the shuttle shuttle vehicles for flight at NASA's Kennedy Space Centre
The CST-100 Starliner will be prepared for flight using a refitted Orbiter Processing Facility, once used to refurbish and prepare the space shuttle vehicles for flight at NASA’s Kennedy Space Centre

The Commercial Crew Transport Programme was recently hampered when both Congress and the Senate pushed for cuts in NASA’s 2016 budget which directly impacted the programme. Both Houses essentially demanded that the funds saved be redirected into NASA’s Orion / Space Launch System programmes – despite the fact neither of those programmes actually needed additional 2016 funding.

As a result of this, it is unlikely the either Boeing’s CST-100 Starliner or SpaceX’s Dragon 2 will enter service until late 2018, forcing NASA to spend additional money in purchasing flight seats aboard Russia’s Soyuz vehicles, currently the only means to fly crews to the ISS.

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