Fifty years ago today, the Mariner 4 mission sent home the first images of Mars. Today, the New Horizons probe sent home gloriously detailed photos of Pluto. Despite the intervening decades, the vibrant excitement of the mission scientists staying up all night to see that first image is exactly the same.

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Colour-by-numbers chart for the Mariner 4 mission to Mars. Image credit: NASA/JPL/Dan Goods

On July 14, 1965, the Mariner 4 probe reached Mars and started transmitting back the very first images of the red planet collected during its flyby. The data was recorded on tape, replayed via radio radios to be picked up by the Canberra antenna of the Deep Space Network. The data was converted by a real-time data translator into numbers printed out on strips of data. Too impatient to await formal image processing, the science team grabbed a box of pastels and hand-coloured the data strips in an adult version of paint-by-numbers. The resulting mosaic was their first-ever look at Mars, and still hangs on the wall at Jet Propulsion Laboratory.

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The heart of Pluto seen by New Horizons from 768,000 kilometers (476,000 miles) away on July 13, 2015. Image credit: NASA/JHUAPL/SwRI

On July 14, 2015, the New Horizons probe prepared for its closest approach to Pluto and started transmitting back the very highest resolution images of the redish dwarf planet collected during its flyby to date. The data was recorded on a solid state drive, replayed via radio waves by a 12-watt transmitter to be picked up by the antenna of the Deep Space Network. The digitized data was processed by a small team of dedicated mission scientists: Carly Howett, Tod R. Lauer, Alex Parker, Simon Porter, and John Spencer stayed up until 3am turning that data into the photograph you’ve been admiring all day.

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Best of all: The two signals arrived within 8 minutes, 20 seconds of being exactly 50 years apart.

Fifty years ago, Mariner 4 was the first spacecraft to send back photographs of a world outside our own Earth-Moon system. In the decades after, we’ve sent probes on flybys, satellites into orbit, and even landers down to the planets of our solar system. We’ve even visited representatives of the smaller bodies: comets, dwarf planets in the asteroid belt, and now our first Kuiper Belt Object. Our robotic explorers are damned impressive, and the scientists who run them are spectacular. And we’re not done with Pluto: we have so many more places to explore in this incredible, outrageous, and, frankly, enormous solar system.

The joy of exploration is contagious, and with the New Horizons probe back in contact and confirmed in good health, the one thing we know for certain is the best is yet to come. It is an excellent time to be small, squishy humans clinging to a fragile fragment of rock in the vast wonder of space.

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Top image: The first image of Mars from Mariner 4 in 1965 [left] and the highest resolution image of Pluto from New Horizons in 2015 [right]. Credits: NASA