This Echo is READ ONLY !   NO Un-Authorized Messages Please!
 ~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

ESA Science News
http://sci.esa.int

03 Dec 2002

When more data can mean more fun
================================

Tomorrow's spacecraft will be capable of generating more data than 
they can transmit to Earth. In some cases, this could be more data 
than can even be comfortably handled by today's computational methods. 
What benefits are there for us in this flood of data?

If you know how to transfer huge quantities of data, you could 
revolutionise some Earthly applications. In the entertainment 
industry, you could transmit films via satellite to waiting cinemas. 
Since the information is digital, audiences would see a perfect 
picture every time.  Film distributors would no longer need endless 
rolls of celluloid film. The menu at cinemas would not be limited to 
feature films either. You could beam sporting events, musical 
concerts, and even news reports into cinemas, showing them live.

ESA scientists may have less fun with the challenges of transferring 
bulk data from space. In 2008, for example, ESA's Eddington will study 
'starquakes' and search for planets, generating a 70-megabyte image 
every few seconds. However, the data link to Earth runs several
hundred times slower, at just 130 kilobytes per second.  Fabio Favata, 
project scientist for Eddington, has an ace up his sleeve. "We know 
which stars we want to observe," he says. On-board computers can send 
back only the information relating to the stars, not the black sky in 
between. This avoids unnecessary transfer.

Sometimes astronomers need information about the whole sky, not just 
about the pinpointed stars. This is the problem facing ESA's 
scientists in the Planck mission.  Planck will survey the whole sky, 
mapping the leftover radiation from the Big Bang. Jan Tauber, Planck's
project scientist says, "We have to retrieve our information in a 
smart way." Planck will compare the data with a computer prediction 
and send back only the differences between the two, thereby 
transmitting smaller numbers, which you can send faster. On Earth, the 
same computer prediction reconstructs the full data record.

Around 2010, another ESA mission, Gaia, will have to work out how to 
manage very large amounts of data. Engineers designed Gaia to discover 
new objects as well as collect data about known ones. To cut down its 
data stream, its on-board software will detect every object that 
enters the spacecraft's field of view. After that, it defines a small
area around the object, and transmits data from that area only. Data 
compression software reduces the size by a factor of five also.

Gaia will generate a staggering amount of usable data, that is, 1 
petabyte (one thousand million million bytes) that scientists need to 
search and process. Even if you could search an individual data record 
each second, searching all the records could easily take 30 years. 
Michael Perryman, Gaia's project scientist admits, "Clearly we have to 
set up a system that will handle this amount of data in sensible 
times." The Gaia team are working with commercial software producers 
to construct one of the most sophisticated, indexed databases in 
history.

Once such a database is developed, we could have huge benefits in 
Earthly applications. Why? Since the Internet itself is one huge 
database, Gaia's advanced techniques could translate into better, 
faster Internet search engines.

Note

At the turn of the third millennium, the Human Genome Project, to map 
the genetic code of a human being, had generated 25 gigabytes (a 
thousand million bytes) of information. At one petabyte, Gaia's 
database will be 40,000 times as large.

USEFUL LINKS FOR THIS STORY

* More about Eddington
  http://sci.esa.int/home/eddington/
* More about Planck
  http://sci.esa.int/planck/
* More about Gaia
  http://sci.esa.int/gaia/
* More about digital cinema
  http://www.esa.int/export/esaSA/ESA8R1OED2D_telecom_0.html

 - End of File -
================

---