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Posts Tagged ‘ESA’

New images of the European Space Agency’s Beagle 2 have emerged recently, suggesting that it came closer to success than has long been thought. These new images have been analysed more thoroughly and carefully than previous images of Beagle 2, and with the help of a computer simulation it is being suggested that Beagle 2 did not crash land. Instead, this team led by Professor Mark Sims of Leicester University are arguing that Beagle 2 deployed, but not completely correctly. They suggest that, due to not deploying correctly, that it may well have done science for a period of about 100 days, before shutting down due to lack of power. They even suggest that there is a very slim possibility that it is still working.

I do have to take issue, however, with the way this story is worded on the BBC website. It implies that we now know, with certainty, that Beagle 2 operated for some period on the surface of Mars. This is not true. One study has argued that it did. One swallow does not make a summer. This particular team’s analysis and study will need to be looked at by others before we can say with any reasonable certainty that Beagle 2 survived its landing.

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New images of Beagle 2 taken by NASA’s Mars Reconnaissance Orbiter have been analysed by a computer model, suggesting it may have actually worked for a short period of time.

As with any suggestion which flies in the face of conventional wisdom, this claim will need to be checked and followed up by others. But, if the evidence is sufficiently strong that Beagle 2 did not crash, then it will come as a relief to those who worked on it and have long felt that it failed in a crash. Sadly, even if it did work, we have not received any data back from it; and that is not going to change.

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The Schiaparelli space probe has been in the news quite a lot this last week or so. It was due to land on the surface of Mars last Wednesday (19 October), but lost contact about one minute before this. On Friday (21 October) NASA released images taken by its Mars Reconnaissance Orbiter which have led ESA to conclude that Schiaparelli exploded on impact, probably due to a failure of the thruster rockets which were meant to guide it gently down over its last few kilometres of descent. For more on that story, see here. This separate story suggests that the failure of the thruster rockets to burn correctly was due to a computer glitch, and that they only burned for 3 seconds instead of the intended 29 seconds.

What has received far less attention than Schiaparelli is the larger spacecraft which transported it to Mars – the Trace Gas Orbiter (TGO). The TGO was successfully put into orbit about Mars after it and Schiaparelli separated. Whilst ESA scientists worried about the silence of Schiaparelli, they were nevertheless jubilant that the TGO had successfully manoeuvred into orbit about the red planet.

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ESA’s Trace Gas Explorer (TGO) transported the lander Schiaparelli to Mars, and is now successfully in orbit about the red planet.

The TGO’s primary scientific mission is to look for traces of methane emanating from Mars. This is of great scientific interest, because methane could be due to life on Mars. Many bacteria on Earth, in particular those that respire anaerobically, emit methane. The best known example are the bacteria which help digest food in the stomachs of many animals, including us. This is why cows are one of the primary sources of methane emission, the gas is coming from the bacteria in their stomachs.

Methane was first detected in the Martian atmosphere in 2003 by NASA scientists. The following year NASA’s Mars Express Orbiter and some ground-based observations detected methane at the level of about 10 parts per billion. Large temporal and positional variations in the methane concentration were measured between 2003 and 2006, which suggests that the methane is  both seasonal and local.

The other possible source of methane is geological activity. Any methane in the Martian atmosphere is quickly broken down by ultraviolet light from the Sun (there is no ozone layer to protect the molecules from UV light, as there is on Earth). This means that any methane present in the Martian atmosphere but have been recently produced. So, how can we tell the difference between methane due to bacteria and methane due to geological activity?

The key is to look for the presence of other gases along with the methane. If the methane is geological in origin it will be accompanied by sulphur dioxide. If, however, it is due to bacteria it will be accompanied by ethane and other similar molecules. The TGO will be able to measure both the methane and these other gases, and so hopefully will help us determine the origin of the methane. In addition, it will be able to measure and image other things, including sub-surface hydrogen down to a depth of a metre. This will help us better map out the amount and extent of subsurface water ice on Mars.

In all, the TGO has four scientific instruments on it, namely

  1. The Nadir and Occultation for Mars Discovery (NOMAD). This instrument has two infrared and one ultraviolet spectrometer channels.
  2. The Atmospheric Chemistry Suite (ACS) has three infrared spectrometer channels.
  3. The Colour and Stereo Surface Imaging System (CaSSIS) is a high-resolution colour stereo camera which will be able to resolve down to a resolution of 4.5 metres on the Martian surface. Being stereo, it will be able to create an accurate elevation map of the Martian surface.
  4. The Fine-Resolution Epithermal Neutron Detector (FREND), a neutron detector which can indicate the presence of hydrogen in the form of water or hydrated minerals. FREND can detect hydrogen down to a depth of 1 metre in the Martian surface.

NOMAD and ACS are the two instruments which will measure the methane and other trace molecules in the atmosphere. Twice each orbit, when the Sun is both rising and setting as seen from the TGO, it will use the passage of the Sun’s light through the Martian atmosphere to detect and measure the presence of trace molecules, down to a few parts per  billion (ppb).

The TGO will orbit Mars at an altitude of 400 km, in a circular orbit taking only 2 hours to orbit once. The orbit will be inclined at 74 degrees to the Martian equator.  It was launched on the 14 March, so took just over 6 months to get to Mars. In 2021 ESA plans to land a rover on the Martian surface, but whether this schedule is delayed due to the failure to successfully land Schiaparelli remains to be seen.

 

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As of 7:30am BST (06:30 GMT) this morning (Thursday 20 October), it is not looking hopeful for the European Space Agency’s Schiaparelli probe. ESA will make a press announcement at 08:00 GMT, when hopefully we will have a better idea of what has happened. As Schiaparelli was descending it should have been sending telemetry data to its mother ship, the Trace Gas Orbiter (TGO). Those telemetry data were relayed back to Earth overnight, so they should be able to give us a much clearer picture of Schiaparelli’s descent to the surface. 

A large ground-based radio telescope in India was able to detect some of the signals that Schiaparelli was sending to the TGO, and certain key events such as the parachutes opening seem to have occurred. But, communication seems to have ceased some 30-60 seconds before Schiaparelli was expected to reach the surface. That, and its subsequent silence, are not good signs and the fear is that the probe has crashed during its final descent. 

I will update this blogpost when we know more, later this morning. In the meantime, keep your fingers crossed. 

***UPDATE***

I’ve just finished watching the live ESA press announcement. The bottom line is that we still don’t know what has happened to the probe. From the telemetry analysed, ESA say that the parachute opened, and all seemed fine until the parachute detached. Loss of signal happened about 50 seconds before the expected touchdown. Nothing has been heard from Schiaparelli since. ESA also suggested that they knew that the rockets to slow its final descent had fired, but at this point in time they do not know how many of the rockets fired or for how long. 

In addition to various satellites which are in orbit around Mars, in addition to the TGO, trying to communicate with Schiaparelli, NASA’s Mars Reconnaissance Orbiter will take images of the landing site to try to find the probe. The same satellite successfully spotted Beagle 2 a few years ago after it went missing in 2003. 

ESA very much put a positive spin on events, emphasising the success of the TGO, and that the telemetry data from Schiaparelli’s decent should help them fully understand what went wrong. They therefore feel that its possible failure should not alter the schedule to send the ExoMars Rover in a few years. 

I will blog more about the science that the TGO plans to do next week, and give an update (if there are any development) on Schiaparelli. 

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Tomorrow (Wednesday 19 October) the European Space Agency (ESA) will attempt to land its probe Schiaparelli on the surface of Mars. Schiaparelli is named after the 19th Century Italian astronomer  Giovanni Schiaparelli who is most famous for observing “canali” on the surface of Mars in 1877. Whereas the word means “channels” in English, it got mis-translated as “canals”, and led to a furore of interest in the possible existence of artificial irrigation channels which it was suggested had been built by Martians to transfer water from the poles to the arid equatorial regions.

All of this was, of course, wrong; but it led to a surge of interest in Mars, including Percival Lowell establishing his observatory in Flagstaff and spending decades observing the red planet. It was this observatory which in the 1910s found the first evidence for the redshift of spiral nebulae (Vesto Slipher), and where, in 1930, Pluto was discovered.

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Tomorrow (Wednesday 19 October) the European Space Agency will attempt to land its probe Schiaparelli on the surface of Mars.

ESA has only attempted once before to land a spacecraft on the surface of Mars; Beagle 2 crash landed in December 2003 and failed to operate. Schiaparelli is a 600-kg lander which is being transported to Mars by its mother ship, the Trace Gas Orbiter. Both are part of ESA’s ExoMars project, which will put a rover on the surface of Mars in 2021.

Schiaparelli is what is referred to as a “demonstrator”, as its purpose is to test various technologies for the landing of the ExoMars rover in 2021. It is planned that Schiaparelli will only operate for a few days, but I suspect that it will end up operating for longer than this. Let us hope that it has a better landing that Beagle 2!

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On Friday (30 September 2016) the European Space Agency’s Rosetta mission ended by crashing the space probe into comet 67P. This was done deliberately. With the comet moving further and further from the Sun, Rosetta’s solar panels were getting to the point where they could not supply enough power to the spacecraft to operate its instruments. Mission scientists had to choose between putting Rosetta into hibernation, with the risk that the probe would not wake up properly when it next came near enough to the Sun, or to deliberately crash the probe into the comet and gain some extra science. They chose to do the latter.

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On Friday (30 September 2016) the highly successful Rosetta mission came to a dramatic end when the space probe was deliberately crashed into the surface of comet 67P.

As Rosetta gently approached the surface of comet 67P (remember, the gravity of the comet is so weak that the fastest that it “fell” was only about 1 metre per second) it took pictures in ever increasing detail. The last image it took is shown above, when the probe was only some 20 metres from the surface.

Rosetta has been a hugely successful mission, and it will take scientists many years to analyse all the data which it and Philae have returned to us. I have blogged about Rosetta before, here, here, here and here.

Some of the most important findings so far are

  • that comet 67P is spongy, with about 70% of its volume being empty space
  • complex organic molecules have been found on the comet’s surface, supporting the theory that the building blocks of life on Earth may have been brought by comets
  • the composition of the water jets emanating from comet 67P was found to be different to water on Earth. This seems to contradict the idea that water on Earth was brought here by comets

There are thousands of images and spectra taken by Rosetta, so there is far more science to come in the future. But, perhaps Rosetta’s greatest success was the way in which the mission captured the public imagination. Surely Rosetta will be just the first mission that we send to orbit and land on a comet.

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Earlier this week it was announced that NASA’s Hubble Space Telescope had observed evidence for water geysers shooting from the surface of Europa, one of Jupiter’s larger moons. Here is a link to NASA’s press release. I was on BBC TV talking briefly about this on Tuesday (27 September), the day after NASA’s announcement.

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NASA has announced that the Hubble Space Telescope has observed water geysers emanating from the south pole of Jupiter’s moon Europa.

In fact, this announcement was additional evidence to add to a finding which had first been announced in 2013. In December 2012, astronomers used a spectroscope on Hubble to look in ultraviolet wavelengths at Europa. They found auroral activity near the moon’s south pole, and upon analysis of the spectrum of the UV emission from this auroral activity they found the spectral signatures of hydrogen and oxygen, the constituents of water.

Those 2012 observations have since been followed up using a different method. This time astronomers have observed how the Sun’s light, which is reflected from Jupiter, is affected as it passes Europa. As Europa transited in front of its parent planet, astronomers looked for signs of absorption of this light near the limb of the moon, which would be due to gases associated with Europa. Such a technique can, for example, be used to find and study the atmosphere of an extra-solar planet as it passes in front of its parent star.

Whilst not finding any evidence that Europa has an atmosphere, what the team found was that absorption features were seen near the moon’s south pole. When they calculated the amount and extent of material required to produce these absorption features they found that their results were consistent with the 2012 finding. They calculate that water jets are spewing out from the surface of Europa and erupting to a height of about 160 km from the moon’s surface.

We have had evidence since the Voyager mission in the 1980s that Europa has an ocean of water below its icy surface. This evidence was further enhanced during the Galileo mission in the 1990s. Where there is water there may be life, so it is possible that Europa’s ocean is teeming with microbial life. To find out, we need to directly study the water in this sub-surface ocean.

Unfortunately, due to the thickness of the icy crust covering its ocean, studying this water directly poses a huge challenge. We currently don’t have the capability to drill through such a large thickness of ice, although it is certainly something we would hope to do in the future. This discovery of water jets provides a much easier way to sample the water directly, and so it is quite feasible that NASA and/or ESA could send a probe to fly through the jet, take a sample of the water, and analyse it to see whether there are any signs of microbial life. This is very exciting, and is why this discovery of water geysers erupting on Europa is so important.

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The European Space Agency’s JUICE mission to Jupiter moved a step closer recently with the signing of an important contract between ESA and Airbus. JUICE stands for JUpiter ICy moon Explorer, and is an ESA mission to send a probe to explore Jupiter and her moons, with a launch date of 2022 and an arrival at Jupiter in 2029. The contract signed with Airbus will see them lead the development and construction of this satellite. There will also be some involvement from NASA and the Japanese space agency JAXA.

Upon arrival at Jupiter, JUICE will manoeuvre to achieve close passes of its moons Callisto and Europa, before settling into orbit about its largest moon Ganymede. Ganymede, together with Europa and possibly Callisto, is believed to have a liquid ocean beneath an icy crust.

 

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Airbus have recently signed a contract with the European Space Agency (ESA) to lead the construction of JUICE, a probe which will be sent in 2022 to study Jupiter’s moons.

The main focus of the JUICE mission will be to see how habitable Ganymede is for microbial life. With liquid water, and heating from the tides caused by Jupiter’s tides, Ganymede, Europa and Callisto are believed to be amongst the most likely places in our solar system for life to have developed. Longer term plans are to build a probe which will be able to burrow through the icy crust of one of these moons and actually look directly for life in their oceans.

 

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