American academics have decided: after Mars, which was chosen ten years ago, they have defined Uranus as the new priority for astronomers and planetary scientists for the years to come. The promise of stunning new discoveries… but we’ll have to be patient.
Every ten years, the most eminent scientists of the American Academy of Sciences, Engineering and Medicine collaborate to produce a very prestigious report which explores both the advances in research since the last edition, but also and above all the avenues that still remain to be explored. In the cosmological chapter of this new version, these specialists have placed a new priority in the foreground: it is aboutUranus, the seventh planet in the solar system.
If this panel of very influential scientists is so interested in this ice giant, it is because it has not been given all the attention it deserves so far. The 2011 version of the report identified another much closer priority, namely Mars. And the least we can say is that this recommendation was followed to the letter.
The next big space exploration project
Since the beginning of the decade, it has been the focus of all attention. In addition to the tirades of Elon Musk who never ceases to proclaim his love for the red planet, we were able to follow heaps of work there, each more impressive than the other; at this very moment, several machines including Curiosity, Perseverance and Ingenuity continue to survey the red planet to discover its secrets.
The last two come fromarrive in the famous delta which constitutes the main objective of their mission, namely to try to find traces of past life. There is therefore reason to be particularly enthusiastic for the rest of the events. But in the shadow of this cosmic superstar, there is no doubt that other celestial bodies also hide real scientific treasures, while NASA and other agencies do not show them the same love.
This preferential treatment is mainly explained by the distances in play. Mars orbits about 211 million kilometers from the Sun; Uranus, on the other hand, is located nearly… Three billion kilometers from the Sun on average. A number that obviously makes it a object particularly difficult to reach; at present, Voyager 2 remains the only craft to have visited this planet. Out of sight out of mind…
…for now, anyway. Because if NASA follows the recommendations of academics as it has once again done for Mars, we can expect that an armada of first-rate scientific instruments will begin to take an interest in it. And that will probably start with the design of a new probe specially dedicated to this purpose.
A fascinating object of study
And the least we can say is that the arguments in favor of this trip are not lacking. Because if Uranus remains very mysterious in many respects, the little information available to researchers is already enough to raise a lot of questions.
The first of these peculiarities concerns its nature. Uranus is considered a giantess of ice, which means that it is mainly composed of gas and liquid. It therefore has no real surface, strictly speaking. A probe could theoretically approach it, but it would be immediately reduced to dust by the dantesque pressure.
On the other hand, it also means that fascinating phenomena take place there; like its close cousin Neptune, we know for example that it shelters real “diamond showers” in the intermediate layers of its atmosphere!
In addition, its axis of rotation also raises many questions. The majority of planets rotate around an axis relatively close to the “vertical” (or to be more precise, perpendicular to the plane defined by the orbit). In Uranus, on the other hand, this axis of rotation is almost parallel to the plane; so she is “lying” in its orbit, as if it had been knocked on its side by a violent impact. In any case, this is one of the hypotheses that will be explored by the researchers.
A host of additional elements to study
Moreover, Uranus also has a nice collection of distinctive elements. It starts with its two sets of rings, although they are not as remarkable as those of Saturn. It also has 27 satellites which have all inherited names taken from works by William Shakespeare or Alexander Pope. And these objects are all very interesting in themselves. They are divided into three categories; there are thirteen small so-called “inner” satellites, nine so-called “irregular” satellites.
But we also and above all find five major moons. Of these, four show evidence of geological processes, active cryovolcanism and fluid circulation; elements that naturally make them priority targets for these future missions.
Suffice to say that the arguments are not lacking, especially since the necessary technology is already perfectly mastered. Among all the projects reviewed by the academicians, the exploration of Uranus therefore appeared as the most mature and pragmatic major space project to date. The report therefore proposes that the logistical and financial bases of the mission be laid as early as 2024.
20 years before the first results… at least
But we will have to wait well beyond this deadline to see the first news from Uranus arrive. To begin, we will have to wait for a appropriate launch window. Indeed, a spacecraft cannot leave when it wishes. It must take into account the respective positions of the departure and arrival planets in their respective orbits.
It can thus save time and resources, but also greatly simplify maneuvers at the end of the race. This is already very important for destinations like the Moon or Mars; but it is even more so when we are talking about such distant objects, where the travel time is counted in decades at best.
Indeed, under optimal conditions, the vehicle could reach Uranus by… 13 years old minimum. And this duration implies being able to play on an effect called “gravitational slingshot” to propel oneself towards Uranus thanks to the gravitational field of Jupiter. Suffice to say, the mission could easily be delayed for decades if it leaves at the wrong time.
To benefit from this gravitational slingshot and reach Uranus in a respectable time, we will have to wait for the planets to align, literally. The next compatible window will not arrive before 2031; this means that in the most optimistic scenario possible, the craft will not reach Uranus before 2043.