ROSETTA DATE FIXED FOR COMET LANDING
The European Space Agency (Esa) has confirmed the date for the landing attempt on Comet 67P as Wednesday 12 November, which is one day later than discussed in provisional planning.
http://www.bbc.co.uk/news/science-environment-29380448
The extra time will give controllers more latitude to get Rosetta into the best position to send the 100kg lander Philae to the comet surface.
Philae will free-fall towards the comet, making contact with the chosen landing site J at 15.35 GMT. Radio signal will take 28 minutes and 20 seconds to reach Esa's ground station on Earth, so confirmation of the landing will come shortly after 16.00 MT.
Philae has no thrusters to control or alter its descent trajectory, so it will land where it will land. Philae could sink into a soft powder or impact ice as hard as rock, or even bounce back into space.
Comment: This is an extraordinarily risky mission, but if successful should provide spectacular results.
Showing posts with label ESA. Show all posts
Showing posts with label ESA. Show all posts
Tuesday, 30 September 2014
Tuesday, 26 August 2014
ROSETTA LANDING SITES CHOSEN
ESA project managers have now selected a longlist of five potential landing sites on Comet 67P:
http://www.bbc.co.uk/news/science-environment-28923010
If the comet is considered to look like a rubber duck, three of the sites are on the head, two are on the body. The neck region has been ruled out
The decision was made principally on operational grounds, where engineers believe the Philae landing probe can touch down on the comet surface with least risk. Other considerations included the need for a location that experiences a day/night cycle, and a place free from boulders and fissures.
Philae is described as 'washing machine-sized'. Comet 67P has a maximum dimension of about 4.5 km.
Landing on a comet has never been attempted before.
A final decision on the landing site is expected by mid-October. The landing attempt is scheduled for 11 November 2014. Due to the distance from Earth, real-time radio control will be impossible. The landing commands will be uploaded several days in advance.
Comment: This is a dramatic and risky mission, but if successful promises to yield valuable scientific understanding about the nature of the comet. The impossibility of real-time control due to the distance involved and the speed of the radio signals is an interesting feature of operating at large distances from Earth. It is significant when, as in this case, important decisions may be required on a timescale short compared to the travel time of the signals.
ESA project managers have now selected a longlist of five potential landing sites on Comet 67P:
http://www.bbc.co.uk/news/science-environment-28923010
If the comet is considered to look like a rubber duck, three of the sites are on the head, two are on the body. The neck region has been ruled out
The decision was made principally on operational grounds, where engineers believe the Philae landing probe can touch down on the comet surface with least risk. Other considerations included the need for a location that experiences a day/night cycle, and a place free from boulders and fissures.
Philae is described as 'washing machine-sized'. Comet 67P has a maximum dimension of about 4.5 km.
Landing on a comet has never been attempted before.
A final decision on the landing site is expected by mid-October. The landing attempt is scheduled for 11 November 2014. Due to the distance from Earth, real-time radio control will be impossible. The landing commands will be uploaded several days in advance.
Comment: This is a dramatic and risky mission, but if successful promises to yield valuable scientific understanding about the nature of the comet. The impossibility of real-time control due to the distance involved and the speed of the radio signals is an interesting feature of operating at large distances from Earth. It is significant when, as in this case, important decisions may be required on a timescale short compared to the travel time of the signals.
Wednesday, 13 August 2014
ROSETTA ORBITS COMET
The European Space Agency spacecraft Rosetta arrived at Comet 67P/Churyumov-Gerasimenko on 6 August on schedule more than 10 years after launch from Earth.
http://www.bbc.co.uk/news/science-environment-28659783
Rosetta is now 550 million kilometres from earth. Signals take 22 minutes between Earth and Rosetta.
Rosetta is now travelling alongside the comet, some 100 kilometres distant, and will continue to follow the comet for the next 15 months. In November a harpoon is planned to anchor a lander Philae to the surface of Comet 67P.
Rosetta carries a thermal imaging spectrometer VIRTIS which has recorded temperatures on the comet around -70 degrees C, about 20 degrees warmer than expected.
Comment: This is a remarkable mission carrying out an important and unique detailed scientific study of a comet. If Philae lands successfully it will be a wonderful technical achievement with potentially significant results for our understanding of comets. Interestingly, because of the small size and low gravity of 67P, Rosetta is not actually in orbit, but is maintained in a triangular path around the comet by firing thrusters.
The European Space Agency spacecraft Rosetta arrived at Comet 67P/Churyumov-Gerasimenko on 6 August on schedule more than 10 years after launch from Earth.
http://www.bbc.co.uk/news/science-environment-28659783
Rosetta is now 550 million kilometres from earth. Signals take 22 minutes between Earth and Rosetta.
Rosetta is now travelling alongside the comet, some 100 kilometres distant, and will continue to follow the comet for the next 15 months. In November a harpoon is planned to anchor a lander Philae to the surface of Comet 67P.
Rosetta carries a thermal imaging spectrometer VIRTIS which has recorded temperatures on the comet around -70 degrees C, about 20 degrees warmer than expected.
Comment: This is a remarkable mission carrying out an important and unique detailed scientific study of a comet. If Philae lands successfully it will be a wonderful technical achievement with potentially significant results for our understanding of comets. Interestingly, because of the small size and low gravity of 67P, Rosetta is not actually in orbit, but is maintained in a triangular path around the comet by firing thrusters.
Tuesday, 29 July 2014
NEW IMAGES OF ROSETTA'S COMET
New images of comet 67P/C-G from the Rosetta probe appear to show the nucleus of the comet is two objects - a smaller 'head' connected by a 'neck' to a larger 'body'.
http://www.bbc.co.uk/news/science-environment-28460702
On 20 July Rosetta was about 5,500 km from the comet. The ESA probe is due to move into orbit on 6 August, when it will be 70 km from the surface of comet 67P, a 4.5 km wide ball of ice.
Then surface mapping of the comet will help select a touchdown zone for a small landing robot called Philae in November.
Dr Holger Sierks from the Max-Planck-Institute in Germany said 'The only thing we know for sure at this point is that this neck region appears brighter compared to the head and the body of the nucleus.' The team say this could be due to a different surface composition or topography in the neck region.
Rosetta will be the first space mission to rendezvous with a comet, follow it and attempt to send a lander to its surface.
Comment: Fascinating detail of 67P from Rosetta which should increase our understanding of the nature of comets.
New images of comet 67P/C-G from the Rosetta probe appear to show the nucleus of the comet is two objects - a smaller 'head' connected by a 'neck' to a larger 'body'.
http://www.bbc.co.uk/news/science-environment-28460702
On 20 July Rosetta was about 5,500 km from the comet. The ESA probe is due to move into orbit on 6 August, when it will be 70 km from the surface of comet 67P, a 4.5 km wide ball of ice.
Then surface mapping of the comet will help select a touchdown zone for a small landing robot called Philae in November.
Dr Holger Sierks from the Max-Planck-Institute in Germany said 'The only thing we know for sure at this point is that this neck region appears brighter compared to the head and the body of the nucleus.' The team say this could be due to a different surface composition or topography in the neck region.
Rosetta will be the first space mission to rendezvous with a comet, follow it and attempt to send a lander to its surface.
Comment: Fascinating detail of 67P from Rosetta which should increase our understanding of the nature of comets.
Thursday, 22 May 2014
ROSETTA INITIATES BIG BURN TOWARDS COMET
The European Space Agency's (Esa) Rosetta spacecraft has lit its thrusters for a near-eight-hour burn to put it on just the right path to meet up with Comet 67P/C-G in August.
http://www.bbc.co.uk/news/science-environment-27498534
There will be eight further manoeuvres, but yesterday's was the big one.
Rosetta is currently 500 million km from Earth. Comet 67P/C-G is travelling round the sun on a big loop that takes it out beyond the orbit of Jupiter and then back in to just inside the orbit of Mars.
Comment: Plenty of chances for things to go wrong before the August rendezvous, but hopefully this exciting mission will be successful.
The European Space Agency's (Esa) Rosetta spacecraft has lit its thrusters for a near-eight-hour burn to put it on just the right path to meet up with Comet 67P/C-G in August.
http://www.bbc.co.uk/news/science-environment-27498534
There will be eight further manoeuvres, but yesterday's was the big one.
Rosetta is currently 500 million km from Earth. Comet 67P/C-G is travelling round the sun on a big loop that takes it out beyond the orbit of Jupiter and then back in to just inside the orbit of Mars.
Comment: Plenty of chances for things to go wrong before the August rendezvous, but hopefully this exciting mission will be successful.
Tuesday, 20 May 2014
CRYOSAT DATA CONFIRM ANTARCTIC ICE LOSS
A new European Space Agency (Esa) Cryosat satellite study shows that Antarctica is now losing about 160 billion tonnes of ice a year to the ocean, twice as much as in the last survey.
http://www.bbc.co.uk/news/science-environment-27465050
Cryosat was launched by Esa in 2010. It has two antennas slightly offset from each other, enabling the detection of not just the height of the ice sheet but the shape of its slopes and ridges. Cryosat is thus more sensitive to details at the steep edges of the ice sheet, where the thinning is most pronounced.
The ice loss is sufficient to increase global sea levels by around 0.43 mm per year. By comparison, total loss of the Antarctic ice could cause a 58 metre sea level rise.
The new study divides Antarctica into three regions; West Antarctica, East Antarctica and the Antarctic Peninsula. All three regions are losing ice, but the Western ice sheet predominates. In particular, the six huge glaciers in the Amundsen Sea Embayment are all being eroded, with the Smith Glacier surface lowering by 9 metres per year.
Professor Andy Shepherd of Leeds University said 'The peninsula is extremely rugged and previous satellite altimeters have always struggled to see its narrow glaciers. With Cryosat, we get remarkable coverage - better than anything that's been achieved before'
Comment: Two other recent studies have focused on the melting of the Amundsen ice sheet. These increasingly accurate measurements of the rate of ice loss in Antarctica are important in understanding the future impact of global climate change.
A new European Space Agency (Esa) Cryosat satellite study shows that Antarctica is now losing about 160 billion tonnes of ice a year to the ocean, twice as much as in the last survey.
http://www.bbc.co.uk/news/science-environment-27465050
Cryosat was launched by Esa in 2010. It has two antennas slightly offset from each other, enabling the detection of not just the height of the ice sheet but the shape of its slopes and ridges. Cryosat is thus more sensitive to details at the steep edges of the ice sheet, where the thinning is most pronounced.
The ice loss is sufficient to increase global sea levels by around 0.43 mm per year. By comparison, total loss of the Antarctic ice could cause a 58 metre sea level rise.
The new study divides Antarctica into three regions; West Antarctica, East Antarctica and the Antarctic Peninsula. All three regions are losing ice, but the Western ice sheet predominates. In particular, the six huge glaciers in the Amundsen Sea Embayment are all being eroded, with the Smith Glacier surface lowering by 9 metres per year.
Professor Andy Shepherd of Leeds University said 'The peninsula is extremely rugged and previous satellite altimeters have always struggled to see its narrow glaciers. With Cryosat, we get remarkable coverage - better than anything that's been achieved before'
Comment: Two other recent studies have focused on the melting of the Amundsen ice sheet. These increasingly accurate measurements of the rate of ice loss in Antarctica are important in understanding the future impact of global climate change.
Thursday, 8 May 2014
ROSETTA CLOSING IN ON 67P
The Rosetta spacecraft carried out a manoeuvre yesterday moving towards an orbit rendezvous with Comet 67P/Churyumov-Gerasimenko on 6 August.
http://www.bbc.co.uk/news/science-environment-27315877
The European Space Agency (ESA) launched Rosetta in 2004. Rosetta carries a lander called Philae due to touch down on the comet in mid-November.
Philae will report back on changes that occur on the surface o 67P as gas and dust lift away from the comet when the icy surface is heated as it moves closer to the Sun.
Comment: As with many of the science probes sent to study distant objects in the solar system, patience is the name of the game. The Rosetta mission is already ten years away from launch, and yet to start the crucial part of its scientific research.
The Rosetta spacecraft carried out a manoeuvre yesterday moving towards an orbit rendezvous with Comet 67P/Churyumov-Gerasimenko on 6 August.
http://www.bbc.co.uk/news/science-environment-27315877
The European Space Agency (ESA) launched Rosetta in 2004. Rosetta carries a lander called Philae due to touch down on the comet in mid-November.
Philae will report back on changes that occur on the surface o 67P as gas and dust lift away from the comet when the icy surface is heated as it moves closer to the Sun.
Comment: As with many of the science probes sent to study distant objects in the solar system, patience is the name of the game. The Rosetta mission is already ten years away from launch, and yet to start the crucial part of its scientific research.
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