A few weeks ago, Donald Trump instructed the U.S. Department of the Treasury to stop producing one-cent (penny) coins. The decision was motivated by the excessively high cost of their production, which is more than three times the face value.
But while inflation has indeed made pennies unprofitable, some rare series coins are highly sought after by numismatists and can sell for seven-figure sums. One example is a 1943 penny mistakenly minted in bronze by the Denver Mint. In September 2010, it was sold at auction for a record 1.7 million dollars.
But there is a one-cent coin that would probably sell for even more money if it were to go to auction now. The fact is that it is not on Earth, but… on Mars. The penny is part of the calibration target of the MAHLI instrument on board the Curiosity rover.
The Martian penny was minted in 1909 in Philadelphia. It was the first year when one-cent coins with the image of Abraham Lincoln appeared in circulation. Their release was timed to coincide with the centennial of the birth of the 16th president of the United States. The choice of coins minted in 1909 was also partly because Curiosity was initially planned to launch in 2009. However, then the launch date was shifted to 2011, but NASA specialists did not change the coin to the mint in 1911.
But what did the penny on Mars require scientists to do? The MAHLI instrument is essentially a microscope: it is designed to take close-ups of rocks and soil. The use of a coin in its calibration target is an homage to an old geological tradition: placing an object of known scale (most often a coin) as a size reference in photographs of rocks so that their scale can be better understood. It also provides the general public with a familiar object that makes it much easier to see the pictures.
Source: NASA/JPL-Caltech/MSSS
Beyond calibration purposes, the penny also serves as a pretty good indicator of conditions on the surface of Mars. In more than 12 years on the surface of the Red Planet, Curiosity has survived dust storms, brutal cold, and sharp rocks that have damaged its wheels. The journey it has traveled is reflected in the penny. When it first arrived on Mars, it was perfectly clean – but has since become covered in a lot of dust.
Source: NASA/JPL-Caltech/MSSS
Now the 1909 penny in good condition is sold at auctions for an average of 10-15 dollars. But the Martian cent, existing in a single copy, of course, would cost much, much more expensive and would instantly become the dream of any numismatist. However, since it is state property and a historical artifact, even if some conqueror of the Red Planet in the future finds Curiosity and takes the coin, it will then be very difficult to legally sell it.
In conclusion, the 1909 penny is not the only coin aboard the spacecraft that might be of interest to collectors. The New Horizons spacecraft that explored Pluto carries a pair of quarters, one minted in Maryland (the state in which it was built) and the other in Florida (the state from which it was launched).
But, there is one important thing. During its journey, New Horizons has reached third space velocity. This means that it will leave the Solar System forever. The spacecraft is now more than 9 billion kilometers from Earth – and is moving another 430 million kilometers away from it every year. So it will be even harder for space numismatists to get quarters from Pluto than a Martian penny.
