Space Sunday: a Martian sandwich

ExoMars unofficial logo
ExoMars unofficial logo (credit: DLR)

If all goes according to plan, at 09:31 GMT on Monday March 14th, a Russian Proton launcher is scheduled to lift-off from the Baikonaur Cosmodrome Kazakhstan, sending the first part of the European ExoMars mission on its way to Mars.

With its suite of high-tech instruments, the Trace Gas Orbiter (TGO) should arrive at the Red Planet on October 19th, 2016, after a journey of 496 million kilometres (308 million miles). While Its main mission is to photograph the Red Planet and analyse its air, the TGO is also carrying a small Mars lander, dubbed Schiaparelli, after the man who first thought he saw canali (as in “groves” or “channels”) on Mars in the 1870s, and thus inadvertently sparked the entire “canals on Mars mythos.

March 11th 2016: the Proton rocket with TGO and EDM on-board is hoisted to the vertical position at its launch pad in the Baikonaur Cosmodrome, Kazakhstan
March 11th 2016: the Proton rocket with TGO and EDM on-board is hoisted to the vertical position at its launch pad in the Baikonaur Cosmodrome, Kazakhstan

A key goal for the TGO mission is to analyse the methane gas which has frequently been detected on Mars by various missions. Methane can either be generated in a biological process, such as microbes decomposing organic matter, or geological ones involving chemical processes in hot liquid water under the surface. However, it also tends to be broken down by  ultraviolet radiation within a few hundred years, so for it to be detected at all on Mars means whatever is producing it is liable to be an active process, and identifying what that process actually is – organic or inorganic – is a crucial part of furthering our understanding of Mars, and could have major ramifications for future missions.

“TGO will be like a big nose in space,” according to Jorge Vago, an ExoMars project scientist. “It will analyse Mars’ methane in more detail than any previous mission and try to determine its origins.”

In addition, TGO will monitor seasonal changes in Mars’ atmospheric composition and temperature in order to create and refine detailed models of the Martian atmosphere. Its instruments will also map the subsurface hydrogen to a depth of a metre, with improved spatial resolution compared with previous measurements. This could reveal deposits of water-ice hidden just below the surface, which, along with locations identified as sources of the trace gases, could influence the choice of landing sites of future missions.

TGO’s findings will also be used to help plan the second phase of the ExoMars mission, due to fly in 2018 (or possibly 2020 due to budget concerns). This will be a solar-powered rover unit, slightly larger than NASA’s MER rovers, Spirit and Opportunity. It’s also a rover with a long gestation period, having been under development for almost 20 years.

Originally designed to be a much bigger vehicle, ExoMars was going to be a joint ESA / NASA undertaking, with ESA supplying the rover and NASA some of the science instruments and the launch vehicle. However, in 2012, NASA arbitrarily withdrew from the project, forcing Europe to go back to the drawing board and seek Russian support for the mission (Russia is supplying the launch vehicle and the landing platform for the rover, as well as some of the science instruments carried aboard both the rover and TGO).

Artist's impression of the ExoMars rover rolling off of its landing platform (credit: ESA)
Artist’s impression of the ExoMars rover rolling off of its landing platform (credit: ESA)

Unlike NASA’s Curiosity mission (but like NASA’s upcoming Mars 2020 mission), ExoMars is intended to directly seek out evidence of current or past microbial life on Mars. As such, the findings from TGO could be key in the selection of the final landing site for the rover. In addition, TGO will also act as the primary communications relay between the rover and Earth.

It is also as a communications relay that TGO will support the Schiaparelli lander. Officially named the Entry, Descent and Landing Demonstrator Module (EDM), Schiaparelli is intended to help ESA in developing the technology for landing on the surface of Mars with a controlled landing orientation and touchdown velocity. Obviously, a safe entry, descent and controlled landing capability is crucial to the success of the ExoMars rover mission, and Schiaparelli will help in determining the final design and development requirements for the rover’s landing systems.

The Schiaparelli EDM
The Schiaparelli EDM

Around 2.4 metres in diameter and 1.5 metres in height, Schiaparelli should operate via battery power for around 4 days following landing, allowing the on-board meteorological DREAMS (Dust Characterization, Risk Assessment, and Environment Analyser on the Martian Surface) package to gather the first measurements of electric fields on the surface of Mars, measure concentrations of dust in the Martian atmosphere and provide new insights into the role of electric forces on dust lifting, the mechanism that initiates dust storms.

Schiaparelli will hitch a lift to Mars aboard TGO, and the two will separate on October 16th, 2016. While TGO manoeuvres into orbit around Mars, the EDM unit will slam into the Martian atmosphere at around 21,000 kilometres per hour (13,000 mph) on October 19th, protected by its heatshield aeroshell. It will then descend through the atmosphere and use retro-rockets to slow the final phase of its descent before dropping the very last metre (3 ft) and relay on a crushable structure, designed to deform, to absorb the final touchdown impact.

Schiaparelli should touch down in the Meridiani Planum during the dust storm season
Schiaparelli should touch down in the Meridiani Planum during the dust storm season

Providing it makes a successful landing on Mars, Schiaparelli will be the second European lander vehicle to have done so. As I reported in January 2015, and over 10 years after it had arrived, it was confirmed that the British built Beagle 2 lander successfully made a soft landing on Mars in 2004, only to suffer a solar panel deployment failure, leaving it deaf and dumb.

A Total Eclipse As you’ve Never Seen It Before

We’re all familiar with solar eclipses, the times when the Moon in its orbit around the Earth comes between us and the Sun. In all, there are four types of solar eclipse, although one is exceedingly rare. They are:

  • A total eclipse, when the Moon completely covers the Sun, as seen from Earth, although totality can only be seen from a relatively small area, roughly 160 km (100 mi) wide and  about 16,100 km (10,00 mi) long. Areas outside this track may be able to see a partial eclipse of the Sun
  • A partial eclipse, when the Earth, Moon and Sun do not align in a perfectly straight line, and the Moon only partially covers the disc of the Sun
  • An annular solar eclipse, when the Moon appears smaller than the Sun as it passes centrally across the solar disk and a bright ring, or annulus, of sunlight remains visible during the eclipse
  • And the rarest of all: a hybrid eclipse, and occurs when an annular eclipse will develop into a total eclipse along its path.

The 8th / 9th March event took the form of a total solar eclipse visible from parts of the southern hemisphere. As usual for these events, it resulted in some remarkable images, such as the one below captured during a NASA webcast of the event, as the Moon and the Sun formed the famous “diamond ring”.

Credit: NASA webcast
Credit: NASA webcast

However, a very unique view of the March eclipse was also obtained from the Deep Space Climate Observatory (DSCOVR), a National Oceanographic and Atmospheric Administration Earth observation and space weather satellite.

Launched in February 2015, DSCOVR occupies a Lissajous orbit at the Sun-Earth L1 Lagrangian point, 1,5million km (930,000 mi) from Earth. From this position, it is able to monitor the solar wind, provide early warning of approaching coronal mass ejections and observe phenomena on Earth including changes in ozone, aerosols, dust and volcanic ash, cloud height, vegetation cover and climate, enjoying a continuous view of both the Sun and the sunlit side of the Earth.

Thus, during a total eclipse, it is in an ideal position not to witness the eclipse itself, but the passage of the Moon’s shadow across the face of the Earth as the Moon transits in front of the Sun; which is precisely what happened during the March 2016 event.

Dawn Images Ahuna

It is now a year since the NASA / ESA Dawn deep-space mission entered an initial orbit around its final destination: the dwarf planet / asteroid Ceres. In that time, the vehicle has been working at various altitudes above Ceres, imaging its surface and revealing some peculiarities along the way.

One of these has been a strange mountain rising from the surface of the tiny world. Dubbed “Ahuna”, the mountain has been the focus of the latest round of images returned by Dawn, taken from a point 120 times closer than when the mountain was first seen. What at first appeared to be pyramid-shaped has revealed itself to be a dome-shaped mountain with smooth, steep walls, with an average elevation of around 4 km (2.5 mi).

"Ahuna Mons" on Ceres perspective view
“Ahuna Mons” on Ceres perspective view (credit: NASA / UCLA)

The problem is, none of this explains why it is there. “No one expected a mountain on Ceres, especially one like Ahuna Mons,” said Chris Russell, Dawn’s principal investigator at the University of California. “We still do not have a satisfactory model to explain how it formed.”

Since moving into its closest orbit around Ceres in December, Dawn had also been unable to image the other major mystery people are keen to learn more about: the white “spots” inside the crate Occator.

First imaged from Earth orbit by the Hubble Space Telescope, and then confirmed in images taken by Dawn in its approach to Ceres and during its first two mapping orbits, the spots and Occator have, because of the Dawn’s mapping orbit and Ceres’ own rotation, remained tantalisingly out of view. However, that recently changed, and the science team are expected to reveal more about Occator and its strange white spots at an upcoming press conference later in March.

InSight Will Fly

And to complete the sandwich, back to Mars for a couple of final items.

In June 2015 I wrote about what had then been due to be NASA’s next mission to Mars: the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander mission. Intended to probe the deep interior of Mars, the mission had at that time been expected to launch this month, taking advantage of the Mars opposition (as is the case with ExoMars).

An artist's impression of InSight on Mars, showing the SEIS package deployed (credit: NASA / JPL)
An artist’s impression of InSight on Mars, showing the SEIS package deployed (credit: NASA / JPL)

However, as I (again) reported in December 2015, the mission’s launch date was put back to 2018, the next period of opposition, due to the repeated failure of the vacuum sphere forming a part of a set of seismometers crucial to the mission’s science package. For a time following the announcement the US $475 million international mission had been put back, there were fears it might even be cancelled.

On March 11th, 2016, NASA announced that the mission would now go ahead, with a target launch date of May 5th, 2018, and that an agreement had been reached between French space agency CNES, originally responsible for the entire seismic package, called the Seismic Experiment for Interior Structure (SEIS) experiment, and the Jet Propulsion Laboratory. This will see JPL design, build and test a new vacuum enclosure, while CNES will be responsible for integrating it into SEIS and testing the completed unit.

The mission critical vacuum sphere originally designed by CNES, and which kept failing tests, will now be replaced by a unit built by the Jet Propulsion Laboratory
The mission critical vacuum sphere originally designed by CNES, and which kept failing tests, will now be replaced by a unit built by the Jet Propulsion Laboratory

The seismometer instrument’s main sensors need to operate within a vacuum chamber to provide the exquisite sensitivity needed for measuring ground movements as small as half the radius of a hydrogen atom. The rework of the seismometer’s vacuum container will result in a finished, thoroughly tested instrument in 2017 that will maintain a high degree of vacuum around the sensors through rigours of launch, landing, deployment and a two-year prime mission on the surface of Mars.

The overall cost of the delay for the mission – which involves researchers from Austria, Belgium, Canada, France, Germany, Japan, Poland, Spain, Switzerland, the United Kingdom and the United States, is unclear. However, estimates suggest it will add between US $75 million and US $150 million to the overall cost of the mission, which covers the development, integration and testing of the new vacuum sphere and the costs associated with storing the completed lander under controlled conditions.

Happy Anniversary, MRO

Ten years ago, on March 10th, 2006, NASA’s Mars Reconnaissance Orbiter (MRO) arrived in orbit around the Red Planet. In the decade since, it has revealed in unprecedented detail a planet that held diverse wet environments billions of years ago and remains dynamic today.

Mars Reconnaissance Orbiter (MRO - credit: NASA / JPL
Mars Reconnaissance Orbiter (MRO – credit: NASA / JPL

Data from MRO have improved knowledge about three distinct periods on Mars. Observations of the oldest surfaces on the planet show that diverse types of watery environments existed, some more favourable for life than others. More recently, water cycled as a gas between polar ice deposits and lower-latitude deposits of ice and snow, generating patterns of layering linked to cyclical changes similar to ice ages on Earth.

as well as being a science platform in its own right, MRO provides crucial support for NASA’s rover and stationary lander missions to Mars. Its observations enable careful evaluation of potential landing sites and help rover teams choose routes and destinations. Together with NASA’s Mars Odyssey, which has been orbiting Mars since 2001, MRO is a crucial link in allowing data to be returned to Earth from surface missions.

MRO’s mission statistics are quite stunning: 1,529.6 million km (956 million miles) travelled since launch; 10 years of continuous operation around Mars; 45,000 orbits completed; 216,000+ images returned to Earth; more than 95% percent of the surface of Mars imaged at various resolutions, 2.4% using the HiRISE system, capable of picking out details the size of an office desk; 264 terabits of data transmitted to Earth – more than the combined total of every other NASA deep space mission.

All told, an impressive mission, and one not yet over. So, happy anniversary, MRO!