Tag Archives: Europa Clipper

NASA cancels overbudget instrument for Europa clipper

Because its budget had ballooned to three times its original estimate, NASA has decided to cancel a science instrument for its Europa Clipper probe to Jupiter’s moon.

[Thomas Zurbuchen, NASA associate administrator for science] said in the memo that, at the time of the February review, ICEMAG’s estimated cost has grown to $45.6 million, $16 million above its original cost trigger and $8.3 million above a revised cost trigger established just a month earlier. That cost was also three times above the original estimate in the ICEMAG proposal. “The level of cost growth on ICEMAG is not acceptable, and NASA considers the investigation to possess significant potential for additional cost growth,” Zurbuchen wrote in the memo. “As a result, I decided to terminate the ICEMAG investigation.”

The contrast between how NASA operates in its unmanned planetary science programs with how the agency operates in its manned programs is striking. The agency’s planetary program is probably its most successful achievement, and has been for decades. Spacecraft almost always get built close to budget, launch on time, and accomplish amazing things when their arrive at their planetary targets, either the Moon, Venus, Mars, Jupiter, Saturn, or Pluto and beyond. Part of the reason for this success is a willingness by NASA to make hard decisions, such as the one above, even if it might ruffle some political feathers. The result is that everyone focuses on getting the job done, on budget and on time. They know that if they screw up, as the ICEMAG team did here, they might find themselves on the chopping block.

In contrast, as I noted in my previous post, NASA allows things to get out of control in its manned program. In fact, they might consider this a feature of the system, not a bug. The goal is not to accomplish anything, but to funnel cash to the states and districts of elected officials. The result is that nothing ever flies, or if it does, it does so very late, very over budget, and often with technical difficulties. Worse, the focus on pleasing corrupt lawmakers like Senator Richard Shelby (R-Alabama) means that NASA is often hostile to the success in manned space by others, such as SpaceX.

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Giant ice pinnacles on Europa

In a new paper scientists note that getting the congressionally mandated Europa Clipper safely to the surface of Jupiter’s moon might be threatened by the existence there of forests of giant five-story high ice pinnacles.

Probes have shown that Europa’s ice-bound surface is riven with fractures and ridges, and new work published today in Nature Geosciences suggests any robotic lander could face a nasty surprise, in the form of vast fields of ice spikes, each standing as tall as a semitruck is long.

Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called “pentinentes,” for their resemblance to devout white-clad monks. First described by Charles Darwin, pentinentes are sculpted by the sun in frozen regions that experience no melt; instead, the fixed patterns of light cause the ice to directly vaporize, amplifying minute surface variations that result in small hills and shadowed hollows. These dark hollows absorb more sunlight than the bright peaks around them, vaporizing down further in a feedback loop.

This work is based on computer models, so it has a lot of uncertainty. It also appears to assume that these pentinentes will be widespread across Europa’s equatorial regions, something so unlikely I find it embarrassing that they even imply it. I guarantee Europa’s surface will be more varied than that. If they are designing Europa Clipper properly, it will go into orbit first to scout out the best landing site, and will be able to avoid such hazards.

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Radiation maps of Europa

By culling together data from Voyager 1 and the Galileo orbiter, scientists have created a radiation map of the surface of Europa.

Using data from Galileo’s flybys of Europa two decades ago and electron measurements from NASA’s Voyager 1 spacecraft, Nordheim and his team looked closely at the electrons blasting the moon’s surface. They found that the radiation doses vary by location. The harshest radiation is concentrated in zones around the equator, and the radiation lessens closer to the poles.

Mapped out, the harsh radiation zones appear as oval-shaped regions, connected at the narrow ends, that cover more than half of the moon.

…In his new paper, Nordheim didn’t stop with a two-dimensional map. He went deeper, gauging how far below the surface the radiation penetrates, and building 3D models of the most intense radiation on Europa. The results tell us how deep scientists need to dig or drill, during a potential future Europa lander mission, to find any biosignatures that might be preserved.

The answer varies, from 4 to 8 inches (10 to 20 centimeters) in the highest-radiation zones – down to less than 0.4 inches (1 centimeter) deep in regions of Europa at middle- and high-latitudes, toward the moon’s poles.

This model, which by the way probably has large margins of error, will be used as a guide by the Europa Clipper scientists now planning that orbiter’s mission.

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