NASA’s Ralph and Lucy set to visit Jupiter’s Trojan asteroids in 2021: Facts on the non-human explorers

NASA’s Ralph and Lucy set to visit Jupiter’s Trojan asteroids in 2021: Facts on the non-human explorers

NASA’s Ralph and Lucy are all set to explore Jupiter’s Trojan asteroids, which are remnants from the earliest days of our solar system.
But Ralph and Lucy are not astronauts — Ralph is a space instrument that has travelled as far as Pluto, while Lucy is a mission payload, or the spacecraft which would be carrying various scientific instruments including Ralph to study the properties of the asteroids.

The mission will be launched in 2021 and would be the very first space mission to study the Trojans..

Lucy and Ralph are heading towards Jupiter’s Trojan asteroidsbut Lucy and Ralph aren’t astronauts. Ralph is a scientific instrument and Lucy is a mission payload which contains several different instruments for measuring the asteroids’ properties. (@NASA) November 7, 2018

About Jupiter’s Trojan asteroids

The Trojan asteroids are orbit Sun in two loose groups — one group is always ahead of Jupiter (called the Greek camp) in its path while the other is always behind (called the Trojan camp).
The two clusters are stabilized at these two Lagrange points in a gravitational balancing act between the Sun and Jupiter
As per the NASA website all of the Trojans are thought to be abundant in dark carbon compounds. Below an insulating blanket of dust, they are probably rich in water and other volatile substances.

What are Lagrange points?
Lagrange points are sweet spots in a planetary orbit where the pull of gravity working from two opposing celestial bodies is balanced due to the centripetal force of their orbits.

Asteroids of the inner solar system and JupiterGreen: Jupiter Trojans, Orange: Hilda asteroids, White: Asteroid belt, Blue: orbits of planets (Source:

The Trojan asteroids in Jupiter’s orbit could be made from the same material as the outer planets which were formed during the birth of the solar system more than 4 billion years ago.
Thus, the data collected on the Lucy mission could provide essential clues about how organic molecules form in primitive bodies, a process that might also have led to the emergence of life on Earth.

About mission Lucy to Jupiter’s Trojan asteroids
The name Lucy’ was taken from the name of the fossil of the earliest human ancestor yet discovered. Just like the finding of this skeleton had provided important insight into human evolution, scientists hope the Lucy mission will also be able to tell us more about our planetary origins.
The Lucy mission will comprise a 12-year journey with a fly-by to seven different asteroids — six Trojan asteroids and a Main Belt asteroid — more than any other previous asteroid mission.
The mission will get us up-close with both the clusters of Trojan asteroids.

Lucy’s orbital path. The spacecraft’s path (green) is shown in a frame of reference where Jupiter remains stationary. After launch in October 2021, Lucy has two close Earth flybys before encountering its Trojan targets. Credits: Southwest Research Institute, NASA

The Lucy mission payload will explore the Trojan asteroids using:

the Long Range Reconnaissance Imager (L’LORRI)
the Thermal Emission Spectrometer (L’TES)

L’LORRI will take high-definition photos of the Trojans, and L’TES will analyze the heat given off of the Trojans’ surface structures

About NASA’s scientific instrument Ralph

Ralph first launched aboard the New Horizons spacecraft in 2006 and obtained stunning flyby images of Jupiter and its moons

This was followed by a visit to Pluto where Ralph took the first high-definition pictures of the iconic minor planet
The instrument will fly by another Kuiper Belt object called 2014 MU69 — nicknamed Ultima Thule — in January 2019. Ralph’s observations of 2014 MU69 will provide unique insights into this small, icy world

Given a name and not an acronym, Ralph enables the study of the composition and atmospheres of celestial objects

NASA’s Ralph scientific instrument (source:

L’Ralph or Lucy Ralph’ and its function on the mission
In 2021, the Lucy spacecraft will carry a near-twin of Ralph, called L’Ralph (‘Lucy Ralph’), to investigate Jupiter’s Trojan asteroid, NASA said in a statement on Wednesday
L’Ralph will detect the Trojan asteroids’ chemical fingerprints, the statement said. It allows scientists to interpret data provided by Sun’s reflected light that are the fingerprints of different elements and compounds.
L’Ralph needs to have many capabilities in a small, light body structure to keep the spacecraft efficient and the mission productive.
L’Ralph’s instrument suite contains the Multi-spectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA). A single telescope collects and focuses the light used in both channels.
This means 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.
Ralph was originally paired with the ultraviolet spectrometer Alice. They were named after the married couple Ralph and Alice Kramden from the television show The Honeymooners’.
Since L’Ralph is using the same concept as the Ralph on New Horizons, Reuter said they wanted to connect the two. And so, Ralph’s lineage was born.

Difference between Ralph and L’Ralph
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.
(With inputs from PTI and IANS)

Read: 12 new moons discovered around Jupiter and one of them is a ‘wrong way driver’
Read: Juno completes one year in Jupiter orbit: Here’s what the NASA spacecraft found so far
Read: Jupiter is the largest and the oldest planet in solar system: Study
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