Final stage Cassini - Saturn mission. Next mission will go to Jupiter in 2022

While less than in 8 months Cassini spacecraft will burn in Saturn atmosphere, it coninues to send us fantastic views of gas giant, its rings and satellites. This raw photo was made on Jan 16, three days ago: it shows tiny 8 km Daphnis satellite, flying in the Saturn Ring A. Daphnis gravity has ripped ring, creating Keeler gap (named after American astronomer James Edward Keeler). Clearly seen as Daphnis makes  "waves" on the edges of Keeler gap: wave on the internal edge goes ahead of Daphnis while wave n the external side of the ring trails behind.

And this photo Saturn North Pole and rings was taken in October 2016. Seems nothing special, but photo from such angle is impossible to obtain from Earth - Cassini was at 25 grad angle to rings plane.

Next Saturn mission was postponed for indefinite time in favor of Jupiter system deep exploration. According to present plans, two separate missions will go to Jupiter system in 2020th - ESA (European Space Agency) JUICE mission  and NASA Europa mission (Europa is second close to Jupiter satellite after Io, not Earth's Europe).

JUICE  (JUpiter ICy moons Explorer) is reformulated version of earlier LAPLACE mission. With price tag more than 1 Billion Euro, it will launched in 2022 with Ariane-5 rocket, arriving at Jupiter planned on January 2030.

Image: ESA

After several dozens Europa and Callisto flybys, it'll orbit Ganymede - the largest Jupiter's satellite and will investigate it from height 500 km during minimum one year. It is highly possible that under icy surface there is water ocean. 

Image: NASA

NASA Europa Mission - NASA mission, launch date still to be defined, but approximately it will happen in 2022 - 2025 with arriving in 2030th. Unlike Ganymede, existence of liquid water ocean under its surface is proved by Galileo spacecraft with probability close to 100%.

Europa - much more interesting object for exploration than Ganymede, because icy surface is thin and tidal forces from Jupiter often break ice, so water plumes go outside. But from the other side, Europa is in the middle of Jupiter's radiation belts and spacecraft's electronics will be subjected to strong radiation.

Image: NASA

Regretfully, budget restrictions have stripped both mission from proposed landers.

Besides, after September 2017 there will be minimum 13 years gap in giant planets investigations, altough filled with Mars and asteroids exploration. 

It seems that for successful Solar System exporation, especially its far outskirts, we need new propulsion systems - chemichal jet thrusters are too inefficient. This is time to bring innovations to space industry, because almost all technologies human use, maybe except of  ion thrusters (they also lack powerful energy sources), had not changed for almost 80 years since Wernher von Braun and his V-2 technologies. 

Interesting that such technologies  are already available: Project Prometheus was started in 2003, but cancelled in 2005. 

Image: NASA

According to info from Russian specialized forum Novosti-Kosmonavtiki, similar project of 1 MWt nuclear energy source for space research is  under development by Russia Roscosmos

There is no detailed info about this project, altough it seems quite realistic.

I personally think that instead spending  money for complex 20 years long projects, it would be more reasonable to develop such transport spacecraft. With it JUICE and Europa Orbiter mission goals could be achieved with one spacecraft, throwing to low orbits dozens of small and cheap cubesat satellites.