Nasa's first planet-hunter, Kepler space telescope, put to rest finally.
According to India Today Network The 'goodnight' command finalises the transition of NASA's planet-hunting Kepler space telescope into retirement. On Thursday evening (November 15), Kepler received its final set of commands to disconnect communications with Earth, the US space agency said in a statement late Friday.
Its retirement began from October 30, when NASA announced that Kepler had run out of fuel and could no longer conduct science.
Coincidentally, Kepler's 'goodnight' falls on the same date as the 388-year anniversary of the death of its namesake, German astronomer Johannes Kepler, who discovered the laws of planetary motion and passed away on November 15, 1630.
"Through its survey, we've discovered there are more planets than stars in our galaxy. As a farewell to the spacecraft, we asked some of the people closest to Kepler to reflect on what Kepler has meant to them and its finding of more planets than stars," NASA said.
The final commands were sent over NASA's Deep Space Network from Kepler's operations centre at the Laboratory for Atmospheric and Space Physics (LASP), at the University of Colorado in Boulder.
LASP runs the spacecraft's operations on behalf of NASA and Ball Aerospace & Technologies Corporation in Boulder, Colorado.
Things you must know about NASA's Kepler
Kepler space telescope is now drifting in a safe orbit around the Sun, 94 million miles away from Earth. It had a profound impact on mankind's understanding of the number of worlds that exist beyond our solar system.
Launched on March 6, 2009, the Kepler telescope combined cutting-edge techniques in measuring stellar brightness with the largest digital camera outfitted for outer space observations at that time.
Originally positioned to stare continuously at 150,000 stars in one star-studded patch of the sky in the constellation Cygnus, Kepler took the first survey of planets in our galaxy and became NASA's first mission to detect Earth-size planets in the habitable zones of their stars.
Kepler's contribution to science
In the 9.6 years in space, Kepler spacecraft completed two missions, observed 5,30,506 stars, discovered 2,662 planets, documented 61 supernovae and helped scientists collect 678 GB of science data. NASA has listed the top science results from Kepler Mission.
Planets outnumber stars
Kepler has proven there are more planets than stars in our galaxy and knowing that revolutionizes our understanding of our place in the cosmos.
Small planets are common
Kepler has shown us our galaxy is teeming with terrestrial-size worlds, and many of them may be similar to Earth in size and distance from their parent stars. The most recent analysis of Kepler's discoveries concludes that 20 to 50 per cent of the stars in the sky are likely to have small, possibly rocky planets that are in the habitable zones of their stars where liquid water could pool on the surface. We still have much to learn about whether any of them could host life.
Planets are diverse
Kepler has discovered a diversity of planet types, opening our eyes to new possibilities. The most common size of planet Kepler found doesn't exist in our solar system - a world between the size of Earth and Neptune - and we have much to learn about these planets.
Solar systems are diverse too
While our own inner solar system has four planets, Kepler found systems with considerably more planets - up to eight - orbiting close to their parent stars. The existence of these compact systems raises questions about how solar systems form: Are these planets 'born' close to their parent star, or do they form farther out and migrate in?
New insights revealed about stars
Besides launching us into the golden age of exoplanets, Kepler has reinvigorated the study of stars. Kepler observed more than a half million stars over the course of its nine years in operation.
Kepler's observations of so many stars have been essential to understanding the basic properties of the planets that orbit them and is enhancing our understanding of the history and structure of our galaxy and the universe.
In particular, Kepler has captured the beginning stages of exploding stars, called supernovae, with unprecedented precision, giving us new knowledge into how these stellar explosions begin.
TESS, the successor of first planet-hunter
Kepler's more advanced successor, the Transiting Exoplanet Survey Satellite (TESS), was launched this April.
TESS is the next step in the search for planets outside of our solar system, including those that could support life. The mission will find exoplanets that periodically block part of the light from their host stars, events called transits.
Built on Kepler's foundation with fresh batches of data, TESS will survey 200,000 of the brightest stars near the sun to search for transiting exoplanets.
What is Transit method: The transit method of detecting exoplanets looks for dips in the visible light of stars, and requires that planets cross in front of stars along our line of sight to them. Repetitive, periodic dips can reveal a planet or planets orbiting a star.
TESS scientists expect the mission will catalogue thousands of planet candidates and vastly increase the current number of known exoplanets. Of these, approximately 300 are expected to be Earth-sized and super-Earth-sized exoplanets, which are worlds no larger than twice the size of Earth.