NASA's Ralph to Explore Jupiter's Trojan Asteroids in 2021

NASA's Ralph, one of the most well-travelled scientific instruments, is set to explore Jupiter's Trojan asteroids aboard the Lucy spacecraft in 2021, the US space agency said.

Ralph has made many discoveries since it first launched aboard the New Horizons spacecraft in 2006. Given a name and not an acronym, Ralph enables the study of the composition and atmospheres of celestial objects.

In 2021, the Lucy spacecraft will carry a near-twin of Ralph, called L'Ralph ("Lucy Ralph"), to investigate Jupiter's Trojan asteroids, which are remnants from the early days of the solar system, NASA said in a statement on Wednesday.

The L'Ralph instrument suite will study this diverse group of bodies. Lucy will fly by six Trojans and one Main Belt asteroid, more than any other previous asteroid mission.

L'Ralph will detect the Trojan asteroids' chemical fingerprints, the statement said. L'Ralph allows scientists to interpret data provided by the Sun's reflected light that are the fingerprints of different elements and compounds.

This data could provide clues about how organic molecules form in primitive bodies, a process that might also have led to the emergence of life on Earth.

L'Ralph needs to have many capabilities in a small, light body structure to keep the spacecraft efficient and the mission productive.

Its instrument suite contains the Multi-spectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA), both of which are fed by the same optics, meaning that Ralph can observe both visible and infrared wavelengths.

These dual capabilities are what makes Ralph and its cousin L'Ralph so special, according to Dennis Reuter, the instrument principal investigator for L'Ralph.

"Most instruments can image visible or infrared wavelengths, but L'Ralph can do both," said Reuter.

Compared to the Ralph that flies with New Horizons, Lucy's L'Ralph has enhanced technology. It can detect a broader spectrum of electromagnetic radiation, it has a moving mirror that reflects light into L'Ralph instead of requiring movements of the entire spacecraft.

Ralph's infrared detectors are 2,000 pixels square, compared to New Horizons Ralph's 256 by 256, allowing for images with more detail.