ESA's Rosetta Probe Catches Target Comet 67P Releasing 10 Ounces Of Water Every Second
June 30, 2014

ESA’s Rosetta Probe Catches Target Comet 67P Releasing 10 Ounces Of Water Every Second

Brett Smith for - Your Universe Online

As the European Space Agency’s Rosetta probe drew closer to its target – comet 67P/Churyumov–Gerasimenko – it was able to pick up data that showed the comet is releasing the equivalent of two small glasses of water into space every second, the space agency said.

The Rosetta probe was able to detect the rate of water vapor being released through the use of the Microwave Instrument for Rosetta Orbiter (MIRO) from nearly 220,000 miles away.

“We always knew we would see water vapour outgassing from the comet, but we were surprised at how early we detected it,” said Sam Gulkis, the instrument’s principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, California.

“At this rate, the comet would fill an Olympic-size swimming pool in about 100 days. But, as it gets closer to the Sun, the gas production rate will increase significantly,” Gulkis added. “With Rosetta, we have an amazing vantage point to observe these changes up close and learn more about exactly why they happen.”

In addition to water, comets are also usually comprised of ammonia, carbon monoxide and methanol. MIRO is built to help ascertain the abundance of each of these compounds, to determine the nature of the comet’s nucleus, the process behind out-gassing and where it occurs on the surface.

These gases emanate from the nucleus along with dust, which forms the comet’s surrounding ‘coma’ or tail. As the comet moves nearer to the Sun, its coma will increase in size and eventually strain from the solar wind will cause the material to stream out even longer. The comet and Rosetta will get closest to the Sun in August 2015, at a point between the orbits of Earth and Mars.

Determining the shifts in the rate of water vapor and other gas release as the icy rock moves around the Sun is crucial for comet science, yet also important for future missions.

“Our comet is coming out of its deep-space slumber and beginning to put on a show for Rosetta’s science instruments,” says Matt Taylor, ESA’s Rosetta project scientist. “Rosetta’s engineers will also be using MIRO’s observations to help them plan for future mission events when we are operating close to the comet’s nucleus.”

As of Monday, Rosetta is within 45,000 miles of its destination. The ESA pilots still need to perform 6 out of 10 total approach maneuvers to make sure Rosetta’s flight path properly aligns with the comet’s orbit.

Earlier this month, the ESA released an image of the comet taken from Rosetta on June 4 that is helping to fine-tune Rosetta’s navigation toward the comet.

“The comet is now almost within our reach – and teaching us to expect the unexpected,” said Holger Sierks from the Max Planck Institute for Solar System Research in Germany.

As Rosetta draws closer to the comet, it will start collecting gas and dust particles from the coma to analyze in its miniaturized on-board laboratories.

“It’s great to have started regularly receiving science data, especially after a long 10 year journey towards our destination,” Taylor said earlier this month. “The variable activity of the comet shows it definitely has personality, which makes us all the more eager to get there to learn just how it ticks.”