A key element of NASA's Europa Clipper is being put through its paces as a prototype of the deep-space probe's High-Gain Antenna (HGA) undergoes testing at the space agency's Experimental Test Range (ETR) at the Langley Research Center in Hampton, Virginia. The HGA will be used to keep the Clipper in contact with mission control as it conducts a series of flybys of Jupiter's moon Europa.

Scheduled to launch sometime between 2022 and 2025, the Europa Clipper mission, as its name suggests, is tasked with making the first up-close, detailed study of the smallest of Jupiter's four Galilean moons. Scientists are particularly interested in Europa because it's believed to possess an ocean sealed beneath its icy crust that is twice the volume of all of Earth's seas and is arguably the most likely place in the solar system to find life outside of our planet.

The problem is that studying Europa is actually a much more complex job than visiting, for example, Mars, so the Europa Clipper is still undergoing a lot of basic design work as NASA determines exactly what its mission objectives and parameters will be.

However, one thing is clear, the Clipper will not go into orbit around Europa. Not only would that be much too expensive in terms of propellant, but the area is far too radioactive for the probe's electronics. Instead, the spacecraft will orbit Jupiter and carry out a series of 45 close flybys of the moon, during which it will study the characteristics and chemistry of the ice crust and the Europan world ocean, as well as the general geology of the moon.

One of the most important bits of equipment on the Clipper is the HGA, which will act as the primary communications link with Earth as the unmanned probe takes up to seven years to reach Jupiter and conducts its over three-year science mission after arrival. Resembling a domestic satellite dish, the HGA is 10 ft (3 m) tall and is being tested by engineers from NASA's Jet Propulsion Laboratory in Pasadena, California, the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and Langley.

The goal is to make sure that the HGA is built to standard and has the required accuracy to keep pointed at Earth across 460 million mi (740 million km). The ETR was chosen to ascertain this because it has the ability to make the close tests required.

"Several years ago we scoured the country to find a facility that was capable of making the difficult measurements that would be required on the HGA and found that the ETR clearly was it,"says Thomas Magner, assistant project manager for Europa Clipper at the Applied Physics Laboratory. "The measurements that will be performed in the ETR will demonstrate that the Europa Clipper mission can get a large volume of scientific data back to Earth and ultimately determine the habitability of Europa."

NASA says that the current tests will end soon, but will resume next year as the design matures.

Source: NASA