Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ESA spacecraft may help unravel cosmic mystery

16.11.2009
When Europe's comet chaser Rosetta swings by Earth tomorrow for a critical gravity assist, tracking data will be collected to precisely measure the satellite's change in orbital energy. The results could help unravel a cosmic mystery that has stumped scientists for two decades.

Since 1990, scientists and mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they exchange with Earth during planetary swingbys.

The unexplained variation is noticed as a tiny difference in speed gained or lost during the swingby when comparing that predicted by fundamental physics and that actually measured after the event.

Tiny unexplained speed variations

The unexplained speed variations are extremely small: NASA's Galileo satellite experienced an increase of just 3.9 mm/s above the expected value when it swung past Earth in December 1990. The largest unexpected variation - a boost of 13.0 mm/s - was observed with NASA's NEAR spacecraft at its Earth swingby in January 1998. On the other hand, variations seen at the swingbys of NASA's Cassini in 1999 and Messenger in 2005 were so small that they lay within the bounds of uncertainty.
ESA's Rosetta has made two Earth swingbys, in 2005 and 2007. It too, experienced the strange anomaly. Frustratingly, Rosetta sped up by an unexplained 1.8 mm/s during the first passage, but experienced no slowing or speeding in 2007. No one knows what will happen on 13 November 2009 for Rosetta's third and last Earth swingby: scientists are stumped.
"It's a mystery as to what is happening with these gravity events. Some studies have looked for answers in new interpretations of current physics. If this proves correct, it would be absolutely ground-breaking news," says Trevor Morley, lead flight dynamics specialist working on Rosetta at ESOC, ESA's European Space Operations Centre, Darmstadt, Germany.

ESA researchers study Rosetta

Together with ESA colleague and orbital mechanics specialist Frank Budnik, Morley co-authored a scientific report in 2006 that studied the Rosetta anomaly during the 2005 swingby and listed possible causes.

These range from tidal effects peculiar to the near-Earth environment, atmospheric drag, or the pressure of radiation emitted or reflected by the Earth, to much more extreme possibilities, such as dark matter, dark energy or previously unseen variations in General Relativity, one of the most fundamental and well-tested theories of modern physics.

One American research team, led by ex-NASA scientist John Anderson, is even looking at the possibility that Earth's rotation may be distorting space-time - the fundamental fabric of our Universe - more than expected, thus affecting nearby spacecraft. But there is as yet no explanation how this could happen.

Before even considering such exotic explanations, all the usual causes of spacecraft speed errors have been thoroughly eliminated by numerous investigations conducted over the years at both ESA and NASA. Software bugs, calculation errors, tracking uncertainties and other, much more mundane, causes have all been systematically eliminated or accounted for, leaving the speed anomaly maddeningly unexplained.

NASA's Pionneer 10 & 11 similarly affected

Scientists at a number of universities and research centres in Europe, the US and Japan have worked on the anomaly problem over the past years. The Earth swingby anomaly has been compared to another unexplained anomaly - one experienced by NASA's Pioneer 10 and 11 spacecraft.
As they travel on trajectories that will take them eventually into interstellar space, both have experienced an unexpected acceleration directed toward the Sun, which has yet to be explained.

Watching through the night

At ESOC on 13 November, the mission control and flight dynamics teams will be watching closely as ESA's 35m New Norcia station in Australia tracks Rosetta during the closest approach, expected at 08:45:40.0 CET, followed - after a visibility gap of 20 minutes - by ESA's 15m Maspalomas station.
The tracking activity will generate highly precise data that will record whether the spacecraft speeds up or slows down more or less than expected. Deep space ground stations operated by NASA, at Canberra, Australia, and Goldstone, California, will also observe the spacecraft before and after closest approach.

ESA/NASA Cassini-Huygens swings by Earth 1999, slowing unexpectedly
"We are using as many ground stations as are available to maximise the amount of swingby data we record. The more data we get, the better the chance that we may eventually come up with an answer," says Morley.
The data is keenly awaited by scientists on a number of continents, who are hoping to see whether the anomaly is present and whether an explanation is finally possible.

"As it stands now, no one knows what's behind this - it really is a mystery. And your prediction as to whether Rosetta will experience any swingby speed anomaly at all on 13 November is as good as anyone's," says Morley.

Jocelyne Landeau-Constantin | EurekAlert!
Further information:
http://www.esa.int
http://www.esa.int/SPECIALS/Rosetta/SEMUCV3VU1G_0.html

Further reports about: ESA ESOC Earth swingby Earth's magnetic field NASA cosmic mystery speed variations

More articles from Physics and Astronomy:

nachricht Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH

nachricht Spin liquids − back to the roots
22.06.2017 | Universität Augsburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>