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Posts Tagged ‘European Space Agency’

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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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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Yesterday (Monday the 20th of January 2014), at 10am (Universal Time) the European Space Agency’s (ESA) space probe Rosetta woke itself up from a 30-month hibernation. Over the next several months Rosetta will travel towards the comet 67P/Churyumov-Gerasimenko, with a planned rendezvous with the comet in August. The rendezvous includes, for the first time, trying to land a probe (called Philae) on the surface of a comet, which is scheduled to happen in November. This is to analyse the comet’s composition and tell us about the nature of the early Solar System. The mission will also monitor the changes which happen to the comet as it gets closer to the Sun on its journey into the inner Solar System.

Comet 67P/Churyumov-Gerasimenko was discovered in 1969. Tracing back its orbital properties, we have found that prior to 1959 it had a different orbit, but its orbit was altered by the gravitational effect of Jupiter. Its current orbit gives it an orbital period of nearly 6.5 years, and it will reach perihelion (closest approach to the Sun) on the 13th of August 2015, when it will come to within 1.25 AUs (about 188 million kms) of the Sun.



The story as covered by the BBC

The story as covered by the BBC



This is one of the ESA’s most ambitious missions. Rosetta was launched way back in 2004, and is currently out near the orbit of Jupiter, some 800 million km from the Earth. It was decided in June 2011 to put the space probe to sleep to save on power, as its solar panels were picking up so little light from the Sun.



A summary of the Rosetta mission.

A summary of the Rosetta mission.



Although Rosetta was scheduled to wake up at 10am UT, the signal that the space probe had successfully woken up was not received back on Earth until 18:16 UT. The faint signal was received by a 70-metre radio dish in California operated by NASA as part of its deep space network.

Analysing the composition of comets is one of the few ways we have to learn about the nature of the early Solar System. In addition, some scientists have argued that many of the complex organic molecules necessary for life were brought to the Earth by comets. It also seems likely that the Earth’s water was brought to our planet by comets, so understanding comets’ composition may be vital in unravelling the mystery of how life got started here on Earth.

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