The space near Europa teems with gases. Some get knocked off Europa’s surface by Jupiter’s relentless radiation. Others might vent into space from Europa's suspected subsurface ocean, or from water trapped in the moon’s ice shell. The MAss Spectrometer for Planetary EXploration/Europa, or MASPEX, will identify those molecules with unparalleled precision.
MASPEX collects gases and converts them into charged particles called ions. It bounces the ions (atoms and molecules missing an electron) back and forth within the instrument. By timing their transit through the instrument, MASPEX determines the ions' mass. The mass reveals each molecule's identity to help determine whether Europa is habitable.How It Works
How It Works
MASPEX generates high-energy (fast moving) electrons to strip electrons from incoming gas molecules. That makes the gas molecules into positively-charged ions. The instrument accelerates the ions to a uniform amount of energy. The ionized gases are pulled into the "drift tube," which gives MASPEX its baguette-like length. The lighter the ion, the faster it can move through the drift tube.
MASPEX bounces the ions back and forth several times in the drift tube before the instrument detects them. The total distance they travel increases their difference in arrival time, magnifying their mass difference. It’s like two siblings in a footrace. Racing across their backyard they might finish at almost the same time. But if they run around the block, their difference in speed is easier to observe.
How We'll Use It“Only together can the instruments crack the mystery of whether Europa can support life.”
How We'll Use It
MASPEX will gain crucial answers from gases near Europa, such as the chemistry of Europa’s surface, atmosphere, and suspected ocean. MASPEX will study how Jupiter's radiation alters Europa's surface compounds and how the surface and ocean exchange material.
“MASPEX has a mass resolution hundreds of times finer than anything that’s flown to space before,” said MASPEX principal investigator James Burch, a planetary scientist and experimental space physicist at the Southwest Research Institute.
Carbon monoxide and molecular nitrogen have nearly equal atomic mass. But the energy binding their atoms alters their mass in telltale ways. MASPEX uses that mass defecit to identify molecules. It also differentiates isotopes – atoms with equal numbers of protons but a different number of neutrons.Meet the Team
Meet the Team
Life might be able to survive in the moon’s subsurface ocean, or in liquid water reservoirs in Europa’s ice. If an ocean or reservoir is erupting into space, MASPEX can analyze its chemistry. “Plumes or gas leakage are the most exciting possibility,” said Christopher Glein, MASPEX co-investigator and a planetary geochemist at the Southwest Research Institute. “We know microbes on Earth exploit any molecule that can serve as a food source. Mass spectrometers are great at sniffing out those molecules.
“We can believe Europa has plumes venting into space, or the right stuff for life,” Glein said. “But it’s like what Carl Sagan advocated: 'I don’t want to believe. I want to know.' Knowing is the goal, and Europa Clipper will be our truth teller,” he said.