A new era of gold for space exploration?


"A bizarre object in the confines of the solar system." Ultima Thule captured by the New Horizons spacecraft. Photo: NASA / UPI / PA Images

I do not remember a year that started with as much enthusiasm about space as this, which explains in part why I found myself sitting in the BBC studios at an absurd hour on New Year's Day morning to talk about it. The Chinese space program was about to land its Chang & # 39; and 4 mission on the opposite side (not the dark side) of the Moon, while NASA's New Horizons spacecraft was fast approaching a bizarre object at the ends of the earth. solar system called Ultima Thule, revealing with a disconcerting seasonality that resembles nothing more than a giant snowman. And everything in the year that marks the 50º anniversary of the first landings of the Apollo moon.

There is more to come, though not so imminent. The BepiColombo mission, a collaboration between the European Space Agency (ESA) and Japan's Aerospace Exploration Agency (JAXA), is currently moving toward Mercury, the smallest and least exploited of our neighboring planets. But it will not be until 2025, because ESA space exploration consultant Mark McCaughrean explained to me while we ate soggy toast on the BBC. You must follow a tortuous route to spill all the speed you gather as you move inland. Sun, allowing it to orbit the planet. ESA also is due to launch a space telescope called CHEOPS this fall to investigate known planets around other stars, while NASA's Mars InSight probe, which landed on the red planet last November, will be working to drill the surface and detect seismic vibrations to better understand the interior of the planet. And JAXA's Hayabusa 2 spacecraft and rovers are currently busy investigating the asteroid 162173 Ryugu, in which the first two robots landed last September.

Humanity is now studying the solar system from its most internal to the most distant regions. And with the Moon and Mars under renewed scrutiny as we remember Neil Armstrong's first footprint in the lunar dust, there is likely to be a discussion about the prospect of getting a human presence once more beyond the Earth's orbit – perhaps first on the Moon, then in Mars. .

Chang and 4 landed safely on the Moon on January 3 – the first time a spacecraft landed on the other side, which had previously only been photographed in orbit. He has dispatched his jeep, called Yutu 2 ("Jade Rabbit", referring to the animal companion traditionally attributed to the Chinese moon goddess Chang? E). So far, the mission leaves no doubt about China's space capabilities, and one may be tempted to interpret the project's chief designer's remark as Yutu 2 descends its ramp – "a small step for the rover, but a great jump to the Chinese. nation "- as a trolling directed at NASA. The allegations of a new "space race" are rather exaggerated – there is more collaboration than competition these days, and ESA in particular is talking to China about a joint base of the Moon for humans in the distant future. But even so, the potential for some rivalry between China and the US can not be denied, even as both are currently led by "strong men" who like to come first. If the humans eventually returned to the Moon, my money would be for them calling home in Mandarin.

But New Horizons offers a remarkable alternative to all this enthusiasm of Apollo-redux. Only robotic missions could venture so far into our cosmic neighborhood (as Frank Close explained, beyond time and distance that humans would receive fatal doses of space radiation on such a long journey). And the New Horizons, in particular, has revealed that riches can be found at its limit. The images he took of Pluto in 2015, with mountains of frozen nitrogen and complex patterns on its icy surface, not only stunned planetary scientists, but began to show the intriguing environment of the Kuiper Belt – the halo of icy and rocky bodies beyond the last real planet Neptune – in fact it is.

Pluto itself, along with its moon Charon, are now recognized as belonging to this family of astronomical objects, named after the Dutch-American astronomer Gerard Kuiper. The main part of the Kuiper Belt extends from the orbit of Neptune to about 4.5 billion kilometers. distance of about 7.5 billion km. Pluto and Charon were the only bodies specifically identified within him until the discovery of another, called Albion, in 1992.

There may be up to a billion such objects, but they appear to be no larger than the size of Pluto's dwarf planet, and are mostly much smaller – too small, then, for the image in any detail of the Earth. . That is why, until New Horizons, Pluto itself was known only as a fuzzy blur. Other relatively large Kuiper Belt objects include Eris, Haumea, and Makemake, with diameters around two-thirds of Pluto, or less. They have been seen so far only as hazy points of light, although the Haumea form has been deduced indirectly as being an egg-like ellipsoid.

Ultima Thule is another of these objects, and now reveals how deeply non-spherical they can be. It seems to consist of two coarse spherical bodies, glued together like the head and body of a snowman, reaching about 33 km from one end to the other. The two-lobed, gravity-welded object rotates every 15 hours, and has a red-rusty surface due to the chemicals formed by the effects of space radiation on the frozen methane and the nitrogen thought to coat it. (Charon has spots of similar hue.)

New Horizons flyby, McCaughrean said, "is the first mission to reach the limit of our solar system" and was able to visualize the objects of the Kuiper Belt in close-up. These bodies "were not affected by the four and a half billion years since the sun was formed," he added, "and therefore contain a record of the early evolution of the solar system." That's why they're scientifically interesting: New Horizons gives us a chance to actually rummage through the original things from which the solar system is made.

This illustrates the fundamental difference between human space flight and the missions unrolled. The first attempts to explore notions of a kind of manifest destiny to venture into the stars – the myth of Columbus rewritten for the space age. But it is the latter who are the real vehicles for science, and who have done more to broaden our horizons and deepen our knowledge about our own corner of the universe.


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