1997 $3 Mars Pathfinder
US #3178 measures 3 inches across and 1.5 inches tall.

On December 10, 1997, the USPS issued its largest postage stamp, honoring the Mars Pathfinder.

NASA launched the Mars Pathfinder on December 4, 1996. The rover landed on Mars on July 4, 1997. Over the next few months, the rover moved across the Martian surface analyzing the planet’s atmosphere, climate, geology, and the composition of its rocks and soil. In all, it sent back 2.3 billion bits of data, 16,500 pictures, and took 8.5 million measurements. Pathfinder sent back its last data transmission on September 27, 1997.

1997 $3 Mars Pathfinder Colorano Silk Cachet First Day Cover
US #3178 – Colorano Silk Cachet First Day Cover

To honor this achievement, the USPS planned a special stamp. Issued on December 10, 1997, the Mars Pathfinder Priority Mail stamp was the last stamp issued that year. The stamp pictures the first image sent from the Pathfinder, the remote-controlled vehicle, Sojourner, which collected data about the soil and rocks, with the Mars landscape in the background. The Mars Pathfinder’s robotic rover was named for Sojourner Truth, an abolitionist and women’s rights activist.

1865 5c Newspaper & Periodical Stamp - hard paper, no gum, dark blue
US #PR1 – The first Newspaper & Periodical stamp.

Measuring 3 inches across by 1.5 inches high, the Mars Pathfinder stamp is the largest US postage stamp ever issued. (Newspaper and periodical stamps issued in 1865 were larger.)  In addition to being the largest US postage stamp, the Mars Pathfinder stamp has several other interesting features.

1978 13¢ Indian Head Penny
US #1734 – America’s smallest postage stamp.

The Pathfinder stamp has special “USA” perforations on the bottom row of perfs. And the vertical perfs extend beyond the stamp to the bottom of the selvage for easier removal of the stamp. Hidden words were incorporated into the design and are visible with a stamp decoder. They read “USPS” and “MARS PATHFINDER • JULY 4, 1997” in alternating lines.

And in case you were curious, the smallest US postage stamp is #1734, the 1978 stamp picturing the Indian Head Penny. It was less than an inch wide!

Discover what else happened on This Day in History.

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  1. My then husband and I were on vacation and stayed up late to watch this on TV. My only problem with the stamp is that it was for Priority postage-had it been for first class rate I would have bought tons of them for my mail!

  2. Learnt something interesting today, about the largest and smallest postage stamps issued by the USPS (the Mars Pathfinder and the Indian Head Penny), both beautiful stamps in their own right…

  3. Look forward to your article every – very educational and brings back great memories. Mystic does more for Stamp Business than any other company – still helps beginners & the little guy. Thanks again –

  4. I will probably buy the Mars Land Rover stamp it looks really cool. I have the smallest stamp already placed in my collection.

  5. Any Chance in ordering these both gems of History. A great way of starting a conversation about Stamp Collecting.

  6. This is a great way of starting a conversation about Stamp Collecting. But most important, is owning a part of Americana. It makes me feel proud to have been around when the both stamps went on the market. Have any good deals on these gems of History?

  7. The Pathfinder project was a very small project at JPL, in the “better, faster, cheaper” era at NASA. The Sojourner was even smaller, an “experiment”, much like the Perseverance helicopter “Ingenuity”, now flying on Mars. The team overcame many obstacles and was very proud of their little rover.

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