NASA’s Kepler telescope is best known for looking for minuscule dips in brightness around stars to spot planets. But that’s not all Kepler is capable of doing. It proved it last month. Between September 7 and September 20 Kepler trained its optics on Comet 67P. The telescope assisted the orbiting Rosetta spacecraft in its final observations of the comet.
While Rosetta peered around the comet’s surface, Kepler looked at the big picture. From its Earth-trailing orbit, Kepler could see the comet’s entire structure – the nucleus and tail.
Did You Know: Kepler orbits the Sun, not the Earth. Telescopes like Kepler don’t want Earth getting in the way. Or, any stray light from the planet’s surface. NASA opted for an “Earth-trailing” orbit taking 372.5 days to complete. Since its launch in 2009, Kepler has fallen about 100 million miles behind Earth.
What can these distant observations tell scientists that Rosetta can’t? Seeing the big picture tells scientists how much material the comet is shedding each day. Every single day, the comet loses material as seen by its tail of gas and dust. As it approaches the sun (perihelion), the amount lost spikes. The more material lost, the more area there is to reflect sunlight. Scientists can measure this reflected sunlight and figure out how much material Comet 67P is losing each day as it coasts through the solar system.
For two weeks, Kepler snapped an image every 30 minutes. The GIF below shows 29.5-hour observation on September 17 and 18. Let’s take a look.
We can see the nucleus moving from top right to lower left with the tail extending behind it. The thin strip slicing through the black background is Kepler’s field of view. All of the other white dots surrounding it show areas Kepler studied during its 10th observing campaign.
The two-week study complements the months of data collected by Rosetta. Researchers will use this data in studies and papers for years to come.
The past six months or so have been a roller coaster for the Kepler team. Earlier this year, the telescope entered emergency mode suddenly. The team managed to fix the issue and get the telescope back to normal operations. Awesome job considering it takes 13 minutes for the spacecraft to receive and send back confirmation of each command. 13 long minutes to know if the command sent was the right one.
Today, Kepler’s systems are all green and the telescope is enjoying a two-year mission extension from NASA.
“With the emergency behind us, and fuel to last us into the summer of 2018 or beyond, the news of a two-year mission extension was a welcomed vote of confidence in the team,” said mission manager Charlie Sobeck.
More than 2,330 exoplanets spotted by Kepler have been confirmed. Look for that number to keep growing over the next couple of years.