Essential Antenna on the ‘Jupiter Icy Moons Explorer’ (Finally) Deploys
When critical radar gear aboard JUICE (Jupiter Icy Moons Explorer) fails because of a stuck pin, engineers try various tricks to fix the problem.
Ever since its invention and deployment in World War II, radar has become an essential backbone of the modern world, with applications ranging from marine navigation to adaptive cruise control. Originally an acronym for radio detecting and ranging, radar technology sends and receives reflected electromagnetic waves to determine the location of objects of interest.
While radar is very useful here on Earth, it also has extensive applications to space exploration. Recently, the European Space Agency (ESA) launched the JUICE mission, which stands for Jupiter Icy Moons Explorer.
Scientists believe Europa, one of Jupiter’s moons, has a subsurface ocean. Image used courtesy of NASA
The goal of the JUICE mission is to explore habitable zones within several moons of Jupiter: Ganymede, Europa, and Callisto. Importantly, the spacecraft is carrying an instrument called RIME—Radar for Icy Moons Exploration. This instrument is specifically designed to penetrate deep into the planetary surface.
RIME Fails to Deploy Properly Due to Stuck Pin
Meanwhile, the goal of RIME is to characterize the surface of Jupiter’s moons as a planetary object and potential habitat for humans in the future. The RIME antenna is an ultra-light Carbon Fiber Reinforced Polymer (CFRP) antenna. CFRP allows RIME to be both lightweight but also durable, making it ideal for an expedition such as JUICE.
According to SpaceTech, the company which designed and manufactured RIME, RIME can withstand temperatures as high as 191℃, which will occur as it passes by Venus, to as low as -269℃. The antenna is connected to circuitry provided by Italy and the United States to process and format the received data.
Internal block diagram of associated processing circuitry connected to RIME. Image used courtesy of the Lunar and Planetary Institute
As SpaceTech demonstrates in their testing video, RIME uses a hinge design to open the antenna. With the recent launch of the JUICE mission, however, the antenna failed to deploy due to a stuck pin. Scientists and engineers at the ESA believed that the stuck pin was causing RIME to not fully deploy.
Without RIME, the JUICE mission would not be able to gather the critical characterization data it set out to, so it was important that engineers determine how to fully deploy it using the limited resources they had at their disposal.
Engineers Use Non-explosive Actuator to Free RIME
According to the ESA, engineers tried a variety of means to move the stuck pin by just enough—as little as a few millimeters—to be able to deploy RIME. From shaking JUICE using its thrusters to warming it with sunlight, results
looked promising but did not free the antenna. Finally, engineers decided to fire a non-explosive actuator (NEA) in the jammed bracket.
Illustration of the JUICE spacecraft at Jupiter. Image used courtesy of ESA
This moved the stuck pin just enough to allow RIME to unfold. In simple terms, an NEA is a device which is used to generate rapid motion without using pyrotechnics to create an explosion (which can be potentially unsafe to the rest of the system). This makes NEAs especially useful for spacecraft applications as it is essential for the system to remain undamaged for a successful mission.
Release of NEA and subsequent damping before the antenna stabilizes in its final position. Image used courtesy of ESA. (Click image to enlarge)
Now that RIME has been deployed, it will be a critical tool to learn more about the surface of Jupiter’s moons, and potentially pave the path to human exploration in the future. While there has been no direct evidence of life on otherplanets so far, there are promising signs of large oceans on moons such as Europa, deep beneath the surface.
The capability of RIME to penetrate deep into Europa’s icy surface could provide scientists with more insight into the geology and habitability of the moon.