Future Timeline

The short answer is, unfortunately, we are too late now with our existing technology. Although 'Oumuamua is moving at a velocity of 26km/s, factoring in Earth's velocity vector, the delta-v between a spacecraft in Earth orbit and the object is closer to 60km/s. "Chemical propulsion just doesn’t close the case in this scenario," Rogers said. "It’s not feasible."

But what if NASA had worked feverishly after detection of the object on October 19 and already sent a probe into space? The problem with our primary propulsion methods is that, while chemical rockets are very good at getting stuff out of Earth's orbit, they're gas guzzlers in space. Most of our existing in-space propulsion systems are based on chemicals, and they need a lot of fuel—often hydrogen—to move a spacecraft about. In this case, Kos calculated the specific impulse needed for chemical rocket engines to catch 'Oumuamua at about 450 seconds.

If artificial, then the possibility of an old derelict or even an automated derelict would be exciting. The best case scenario for both humanity knowing it's not alone anymore and reverse engineering the technology without worry of a potential hostile space power.

There currently does not exist any hypothesis that explains the anomalous properties of ‘Oumuamua without invoking either impossible or speculative formation mechanisms. I would personally love to see new theories about ‘Oumuamua. But we probably have to wait for the next one.

Mr Wright, any comments to the recent news that Oumuamua is not a nitrogen iceberg? What can it be?

Not really my field, but I think the N2 iceberg hypothesis still works well. We're working from very limited data on a new phenomenon, so nothing will seem to fit exactly until we see another one and can get better data on it.

Most likely there are lots of Oumuamua's floating around, but we can't detect them yet.

(Sky & Telescope) At the Division for Planetary Sciences meeting in October, Ari Heinze (now at University of Washington) reported preliminary results for an asteroid, 2016 AK193, that behaves remarkably like ‘Oumuamua: It tumbles like the interstellar object did, and it seems to be just as elongated to boot.

But unlike ‘Oumuamua, this asteroid is not a new arrival; it has probably been going around the Sun for billions of years. Time will tell if its origins shed light on ‘Oumuamua’s mysteries.
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“‘Oumuamua was a huge mystery because there has literally never been anything like that seen before,” says Darryl Seligman (University of Chicago), who was not involved in the observations. “So if there's anything that's close to that in the solar system, just from that standpoint, it's worth following up.”

Follow-up will take some patience, though — 2016 AK193 is a near-Earth object, but that doesn’t mean it’s near Earth at all times. It won’t come close enough to observe again until 2029, Heinze says. When it does, it’ll approach within 0.05 astronomical unit of Earth, appearing at about 18th magnitude.

“Hopefully there will be some detailed studies then (e.g., radar imaging plus lots more photometry),” Heinze says, “but there is very little prospect for additional useful measurements in the intervening seven years.”