SoylentNews

hubie [soylentnews.org] writes:

"You don't have to claim that they're aliens to make these exciting" [arstechnica.com]:

[...] Anyone who studies planetary formation would relish the opportunity to get a close-up look at an interstellar object. Sending a mission to one would undoubtedly yield a scientific payoff. There's a good chance that many of these interlopers have been around longer than our own 4.5 billion-year-old Solar System.

One study from the University of Oxford [skyatnightmagazine.com] suggests that 3I/ATLAS came from the "thick disk" of the Milky Way, which is home to a dense population of ancient stars. This origin story would mean the comet is probably more than 7 billion years old, holding clues about cosmic history that are simply inaccessible among the planets, comets, and asteroids that formed with the birth of the Sun.

This is enough reason to mount a mission to explore one of these objects, scientists said. It doesn't need justification from unfounded theories that 3I/ATLAS might be an artifact of alien technology, as proposed by Harvard University astrophysicist Avi Loeb [medium.com]. The scientific consensus is that the object is of natural origin.

Loeb shared a similar theory [arstechnica.com] about the first interstellar object found wandering through our Solar System. His statements have sparked questions in popular media about why the world's space agencies don't send a probe to actually visit one. Loeb himself proposed redirecting NASA's Juno spacecraft [medium.com] in orbit around Jupiter on a mission to fly by 3I/ATLAS, and his writings prompted at least one member of Congress [harvard.edu] to write a letter to NASA to "rejuvenate" the Juno mission by breaking out of Jupiter's orbit and taking aim at 3I/ATLAS for a close-up inspection.

The problem is that Juno simply doesn't have enough fuel to reach the comet, and its main engine is broken [arstechnica.com]. In fact, the total boost required to send Juno from Jupiter to 3I/ATLAS (roughly 5,800 mph or 2.6 kilometers per second) would surpass the fuel capacity of most interplanetary probes.

Ars asked Scott Bolton, lead scientist on the Juno mission, and he confirmed that the spacecraft lacks the oomph required for the kind of maneuvers proposed by Loeb. "We had no role in that paper," Bolton told Ars. "He assumed propellant that we don't really have."

[...] Loeb's calculations also help illustrate the difficulty of pulling off a mission to an interstellar object. So far, we've only known about an incoming interstellar intruder a few months before it comes closest to Earth. That's not to mention the enormous speeds at which these objects move through the Solar System. It's just not feasible to build a spacecraft and launch it on such short notice.

Now, some scientists are working on ways to overcome these limitations.

One of these people is Colin Snodgrass, an astronomer and planetary scientist at the University of Edinburgh. A few years ago, he helped propose to the European Space Agency a mission concept that would have very likely been laughed out of the room a generation ago. Snodgrass and his team wanted a commitment from ESA of up to $175 million (150 million euros) to launch a mission with no idea of where it would go.

ESA officials called Snodgrass in 2019 to say the agency would fund his mission, named Comet Interceptor, for launch in the late 2020s. The goal of the mission is to perform the first detailed observations of a long-period comet. So far, spacecraft have only visited short-period comets that routinely dip into the inner part of the Solar System.

[...] Long-period comets are typically discovered a year or two before coming near the Sun, still not enough time to develop a mission from scratch. With Comet Interceptor [esa.int], ESA will launch a probe to loiter in space a million miles from Earth, wait for the right comet to come along, then fire its engines to pursue it.

Odds are good that the right comet will come from within the Solar System. "That is the point of the mission," Snodgrass told Ars.

[...] "You don't have to claim that they're aliens to make these exciting," Snodgrass said. "They're interesting because they are a bit of another solar system that you can actually feasibly get an up-close view of, even the sort of telescopic views we're getting now."

[...] Snodgrass sees Comet Interceptor as a proof of concept for scientists to propose a future mission specially designed to travel to an interstellar object. "You need to figure out how do you build the souped-up version that could really get to an interstellar object? I think that's five or 10 years away, but [it's] entirely realistic."

Scientists in the United States are working on just such a proposal. A team from the Southwest Research Institute completed a concept study showing how a mission could fly by one of these interstellar visitors. What's more, the US scientists say their proposed mission could have actually reached 3I/ATLAS had it already been in space.

The American concept is similar to Europe's Comet Interceptor in that it will park a spacecraft somewhere in deep space and wait for the right target to come along. The study was led by Alan Stern, the chief scientist on NASA's New Horizons mission [arstechnica.com] that flew by Pluto a decade ago. "These new kinds of objects offer humankind the first feasible opportunity to closely explore bodies formed in other star systems," he said.

It's impossible with current technology to send a spacecraft to match orbits and rendezvous with a high-speed interstellar comet. "We don't have to catch it," Stern recently told Ars. "We just have to cross its orbit. So it does carry a fair amount of fuel in order to get out of Earth's orbit and onto the comet's path to cross that path."

[...] A mission to encounter an interstellar comet requires no new technologies, Stern said. Hopes for such a mission are bolstered by the activation of the US-funded Vera Rubin Observatory, a state-of-the-art facility high in the mountains of Chile set to begin deep surveys of the entire southern sky later this year. Stern predicts Rubin will discover "one or two" interstellar objects per year. The new observatory should be able to detect the faint light from incoming interstellar bodies sooner, providing missions with more advance warning.

"If we put a spacecraft like this in space for a few years, while it's waiting, there should be five or 10 to choose from," he said.

[...] "Each time that ESA has done a comet mission, it's done something very ambitious and very new," Snodgrass said. "The Giotto mission was the first time ESA really tried to do anything interplanetary... And then, Rosetta, putting this thing in orbit and landing on a comet was a crazy difficult thing to attempt to do."

"They really do push the envelope a bit, which is good because ESA can be quite risk averse, I think it's fair to say, with what they do with missions," he said. "But the comet missions, they are things where they've really gone for that next step, and Comet Interceptor is the same. The whole idea of trying to design a space mission before you know where you're going is a slightly crazy way of doing things. But it's the only way to do this mission. And it's great that we're trying it."

Original Submission