While the orbiter would gather a great deal of interesting and valuable information, it falls short of what the flyby concept could deliver on a dollar-to-dollar basis, Senske said. For example, a $2 billion orbiter would not be able to carry an instrument that could investigate the composition and chemistry of Europa's surface and atmosphere (and, by extension, its ocean).
"In terms of an apples-to-apples comparison, Clipper really does rise to the top," Senske said.
The Europa Clipper
The Clipper would carry a number of scientific instruments, including ice-penetrating radar, a topographical imager, a magnetometer, an infrared spectrometer, a neutral mass spectrometer and a high-gain antenna.
To squeeze all of this gear aboard and still stay under the $2 billion cap, Clipper may need to be powered by solar arrays rather than advanced stirling radioisotope generators as originally envisioned, Senske said. Solar panels are considerably cheaper than ASRGs, which convert the heat from plutonium-238′s radioactive decay into electricity.