That comet landing could save us all from an asteroid-y death one day

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On November 12, the European Space Agency (ESA) made space history when it landed a probe on a comet. The news swept the Internet by storm (even holding our attention over Kim Kardashian's Internet-breaking behind,) but will likely be forgotten as the news-cycle cycles on. That probe, however, is worth remembering, for several reasons — including that it could help save us from an asteroid-y death.

The Philae lander, which was launched from the Rosetta orbiter hours before it became the first to touch down on a comet ( sadly, it may already be on its last legs) is largely designed to help scientists learn more about Earth’s history. “With Rosetta we are opening a door to the origin of planet Earth and fostering a better understanding of our future,” says ESA chief Jean-Jacques Dordain in a press release. ESA Rosetta project scientist Matty Taylor adds, “Rosetta is trying to answer the very big questions about the history of our Solar System. What were the conditions like at its infancy and how did it evolve? What role did comets play in this evolution? How do comets work?”

With material gathered from Philae, scientists hope to learn about the early days of our planet. The New York Times explains that “ one of the central mysteries that Rosetta will explore is whether Earth’s oceans are filled with melted comets. Since the rocky bits that came together to form the planet were dry, water has to have come from somewhere else. One possibility is that comets slamming into the Earth early on seeded it with water.”


The mission will also provide us with views from and of comet 67P/Churyumov–Gerasimenko, plus “on-the-spot analysis of the composition of the comet’s surface materials," measurements of “ the electrical and mechanical characteristics of the surface,” and comet songs, among other things.

The ESA’s successful comet-chasing mission has indirect implications for it’s Near-Earth Object (NEO) mission, as well. That’s the the arm of the ESA tasked with figuring out what to do if an asteroid, or a comet, is found to be on a collision course with the Earth.

ESA scientist Detlef Koschny, who works on the NEO team as well as on the Rosetta team, explains that though the projects are not related, the information gathered by Philae will be useful for NEO. Analysis from data drawn from Philae “will tell us a lot about the gravitational field on the comet. That’s definitely something we need to understand if we needed to characterize an asteroid that could hit our planet,” says Koschny, adding, “Our NEO programme follows Rosetta very closely… While most of the NEOs we are worrying about are asteroids, not comets, the basic scientific results are important anyway: How does the information we get with remote instrumentation compare to what the object really looks like?… Basically for all NEOs all we have are remote observations, ground based — now we can see how accurate these are.”

Koschny, who works on both projects, is in a unique position. “The Rosetta Mission was purely done as a science mission. Our near-earth object program, which we are doing now, is done to save the world, to protect the world, to make the world a safer place. That’s not in the science program in ESA — it’s located in the operational directorate.”


He adds that though it’s unusual for scientists to work on two projects in tandem, there is a sequential option: Scientists who work on Rosetta now could work on NEO next. “There is a common study between ESA and NASA for an asteroid deflection mission, called AIDA (Asteroid Impact Deflection Assessment). The idea is to go to binary asteroid Didymos, observe the system for a while, then impact the secondary asteroid. By the change in the orbital period about the primary we can assess the efficiency of the deflection. Rosetta, and in paricular the landing, teaches us a lot about how to navigate around such a small object… Currently this is only a study, but we are already talking to our Rosetta colleagues for planning the mission. If the mission were really approved to be launched, I'd definitely want the people that now did all the navigation for Rosetta and the Philae lander in the team!”

Just another reason to love Philae.

Danielle Wiener-Bronner is a news reporter.

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