Artist concept depicts multiple-transiting planet systems - stars with more than one planet orbiting it - that have been discovered recently by NASA's Kepler mission. )(NASA)

Artist conception of multiple transiting planet systems – stars with more than one planet orbiting it – discovered recently by NASA’s Kepler mission. (NASA)

NASA’s planet-hunting Kepler mission stirred up excitement this week when mission officials announced they’d hit the proverbial jackpot – discovering and confirming a record 715 new planets orbiting 305 stars.

Nearly 95 percent of these newly found planets are smaller than Neptune, but four are about 2.5 times bigger than Earth and are located within what scientists call the habitable zone, meaning they are just the right distance from their parent stars for liquid surface water, an important element of life, to form.

Artist rendering of NASA's TESS - Transiting Exoplanet Survey Satellite in space (NASA)

Artist rendering of NASA’s TESS – Transiting Exoplanet Survey Satellite in space (NASA)

Even though the spacecraft was hobbled last summer after experiencing problems with accurately pointing its telescope, Kepler accumulated so much observational data during its operational time that astronomers will have plenty of information to wade through which could lead to possible new discoveries.

Meantime, NASA and the European Space Agency (ESA) aren’t wasting any time preparing the next generation of planet-hunting missions.

NASA plans a 2017 launch of its Transiting Exoplanet Survey Satellite (TESS). The TESS space telescope, which will be equipped with an array of telescopes, will conduct an all-sky survey.

TESS will be on the lookout for a variety of transiting exoplanets – planets that are detected when their host stars dim as they pass – that orbit the nearest and the brightest stars the sky.

TESS will look for and identify gas giant planets as well as Earth-like planets orbiting within their host stars’ habitable zone.

WFIRST-AFTA (Wide Field Infrared Survey Telescope - Astrophysics Focused Telescope Assets) rendering of on-orbit situation. (Mark Melton, NASA/GSFC)

Artist rendering of WFIRST – Wide Field Infrared Survey Telescope (NASA)

Sometime in the early 2020s, NASA plans to launch an ambitious mission called The Wide Field Infrared Survey Telescope (WFIRST).

The WFIRST is an infrared space observatory that will not only join the search for potentially habitable extrasolar planets, but will help scientists learn more about the nature of dark energy and why the universe is rapidly expanding.

Scientists are also hoping WFIRST will help them learn more about how stars, galaxies and black holes form and evolve.

Just last week, ESA announced it has green-lighted an initial six-year mission that will join the search for alien planets orbiting within neighboring star systems.

The Planetary Transits and Oscillations of stars (PLATO), a space-based observatory, will launch on a Soyuz rocket from Europe’s Spaceport in Kourou, French Guiana, sometime between 2022 and 2024.

An artist's drawing of one of ESA's proposed PLATO space telescopes - notice the bank of 34 telescopes.(© ESA)

An artist’s drawing of one of ESA’s proposed PLATO space telescopes. Notice the bank of 34 telescopes.(© ESA)

PLATO will feature 34 separate telescopes  searching for planets among up to a million stars.

ESA said PLATO will observe and monitor stars that are relatively nearby and will look for planets, especially those that are Earth-like and super-Earth-like, that transit in front of them.

Along with looking for planets located in a star’s habitable zone, PLATO will also examine seismic activity in a discovered planet’s host star enabling scientists to learn more factors such as its mass, radius and age.

ESA officials are also planning to couple various measurements made by PLATO along with ground-based radial velocity observations. Joining data from these two sources should help scientists calculate an exoplanet’s mass and radius so they can get an idea its composition.