In its recent 2016 budget request, the White House allocated $18.5 billion to NASA. Of this proposed amount, $30 million will be set aside in a additional funding to fulfill one of the most highly anticipated missions astrobiologists have long sought to realize: sending a spacecraft to study the icy moon Europa for signs of alien life.
Europa has captivated the fascination and intrigue of scientists and star gazers for decades. Europa, which is one of Jupiter’s 67 known moons, is suspected of harboring an ocean underneath its icy surface, which shows visible signs of striated cracks and streaks. It has also been observed spewing plumes of water vapor as high as 125 miles (200 km) above Europa’s surface, which NASA’s proposed mission to Europa hopes to study and analyze.
NASA’s Hubble Space Telescope first spotted these water vapor plumes in 2012. Although scientists are still debating the frequency and existence of these plumes, if true, they offer the best chance we have of sampling the chemical composition of Europa’s liquid water.
The Europa Clipper
While landing a rover capable of drilling beneath the icy shell of Europa is ideal, NASA is planning a more modest approach by using the $30 million to develop and launch a space probe meant “to measure and map the moon’s ice shell.” Tentatively called the Europa Clipper, this $2 billion unmanned probe will take approximately 8 years to reach and enter into Jupiter’s orbit, which it will then use to make 45 flybys of Europa “at altitudes ranging from 16 miles to 1,700 miles (25 km to 2,700 km).”
Over 3.5 years, the Europa Clipper will analyze Europa’s subsurface ocean, with a focus on studying the “water’s depth, salinity and other characteristics.” Grunsfeld has also expressed interest in using the probe to fly through Europa’s water vapor plumes with the hope of collecting sample materials that an onboard instrument can analyze for existing biomolecules and amino acids. The discovery of such compounds would definitely hint at the existence of alien life. According to astrobiologist Chris McKay, “If you get 20 amino acids, all with the same chirality [a property of asymmetry], that would be, I think, compelling.”
The existence of Europa’s water vapor plumes are still in question, and even if they do exist, timing the probe’s fly-through poses significant logistical challenges of timing, direction and orientation. NASA is planning to confirm the existence of these water vapor plumes this May when the Hubble Space Telescope will perform additional observations of Europa’s southern pole region, where the plumes are expected to exist.
If NASA’s budget gets approved and all goes accordingly, the mission should launch in 2022 and arrive in 2030. Duration of travel, however, may be shortened should NASA decide to use its Space Launch System megarocket.