Voyager 2 Finally Enters Interstellar Space
Voyager 2 has become the second probe to break through the Heliopause.
One of the most popular explorers of our age, Voyager 2, was launched on 20th August 1977 with the intentions of studying the outer planets. However, it exceeded all the expectations (just like its twin Voyager 1) and entered the interstellar space on 10th December (date of announcement), after examining our solar system for more than 40 years.
It is the only spacecraft to study Uranus and Neptune during planetary flybys. Researchers observed significant differences in the data provided by Voyager 2 in comparison to the first journey out (Voyager 1). Ed Stone, the Project Scientist for the Voyager Mission, described that to the world in the following words:
“Very different times, very different places, similar in characteristics. The next months ahead could be very revealing as well.”
The grand departure of Voyager 2 was being anticipated since late August as researchers observed that the spacecraft was approaching the Heliopause, a bubble of charged particles created by solar wind which is generally considered the boundary between our solar system and the interstellar space. Once a spacecraft crosses this bubble, it experiences much stronger cosmic rays than our neighborhood.
Voyager 2 is equipped with a couple of instruments that can detect these high-energy particles as they collide with the space probe. Scientists witnessed a transition from lower-energy particles to nearly none of them which was followed by a sudden surge of high-energy cosmic rays. This was the event which showed that Voyager 2 has now gone beyond the influence of our sun.
Despite the announcement, scientists acknowledge that this is a difficult transition to predict because Voyager 2 is only the second spacecraft to cross that part of space with operational instruments. The fact that the Heliopause never forms a perfect sphere and is dependent on the ebb and flow of solar wind makes it increasingly tough for the researchers to confirm a cosmic departure. That’s the reason why they waited for the data before announcing the grand exit. Rob Decker, a part of the Voyager Mission team, stated that they observed something weird on 5th of November. Later research clarified that that something was the event of crossing the Heliopause.
Scientists are much more excited for this crossing than the first one because an instrument, called the Plasma Science Experiment, is still working on Voyager 2 while it had stopped long before the Heliopause in case of Voyager 1. This effectively means that this space probe will not only create new data but it will also produce a new type of data. The comparison of both the trips also revealed how uneven this journey to interstellar space could be. Voyager 1 created a lot of dynamic data as it ran into flux tubes while its twin didn’t get any of that. However, it did get a strange bump in some of the data. Stone referred to them by saying,
“We haven’t yet sorted out what these features are.”
The good news is that both Voyager 2 and its twin spacecraft have quite a lot of life left in them. The world was informed about that at the Annual Meeting of the American Geophysical Union. Scientists expressed hope that these probes will continue to provide invaluable data about the interaction of solar wind with the interstellar wind. Suzanne Dodd, the Project Manager for the Voyager Interstellar Mission, mentioned that both the spacecraft are quite healthy if you consider them senior citizens and the journey could go on for years if all goes well.
Coping with the gradual loss of heat and power is the most important challenge for the mission team. Voyager 2 is currently operating in 3.6o C. The power production capabilities of the probe will decrease by 4 watts/year at this rate. Therefore, certain instruments of the spacecraft will have to be shut down to extract as much science out of this probe as possible. Dodd believes that these twin probes can survive for at least 5 years and their journey can possibly be extended to 10 years. She wants to complete full 50 years of these spacecraft since their launch in 1977. She said,
“I think that would be fantastic.”
Voyager 2 enjoyed a lot of success while it was exploring our solar system. Firstly, it is the only spacecraft to have visited all the gas giants (Jupiter, Saturn, Uranus, and Neptune). Similarly, it discovered a lot of amazing phenomena including the cracks in the ice shell of Europa and the Great Dark Spot on Neptune.
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