Number 5: Mariner 2, Mariner 4, and Mariner 10!

Hey, Sky Fans!

It’s fourth night of Hanukkah! What should we talk about tonight? How’s the dreydeling going?

If you’re just tuning in, for Hanukkah each year, I like to put together a year-end list of various space things. this year, we’re talking about uncrewed space probes, flybys and orbiters. I hope if you like the list, you’ll spread the word; like, comment, share.

I like that… maybe I’ll rename this site Various Space Things.

The list so far:

    1. Luna 3
    2. Giotto
    3. Magellan

Where to next?

Number 5: Mariner 2, Mariner 4, and Mariner 10!

For tonight, let’s head back to the early days of the space program. Most of us remember, have seen, or at least heard, the famous speech by President John F. Kennedy. On a warm, late summer Houston day, he stood in front of the crowd at Rice University and, with strength and intellect, tried to convince America to rally behind the effort he laid out a year or so earlier: to send astronauts to the Moon and bring them home safely.

That was in September of 1962. He’d only been in office a year and a half or so. All these years later, it’s easy to pull the Apollo program out of history and, isolate it, and assume that’s all that was going on. This is with good reason: people walking on the Moon is pretty great.

But during that speech at Rice, as the crowd erupted while the president said “We choose to go to the Moon!” a robot cruised through the dark and empty, falling inward toward the parts of the solar system closer to the Sun.

Mariner 2 left Cape Canaveral aboard an Atlas rocket in August 1962, after Mariner 1  was lost. After a couple of mid-flight hiccups, in December, it reached its main goal and flew within about 35,000 km / 22,000 miles of the planet Venus.

It had no camera, and it could send no photos or movies back to Earth, but it did something amazing:

Mariner 2 made it to Venus.

That was the first time humans managed to get a visitor to another planet. While it was nearby, it took loads of readings, measured the temperature of its clouds and learned for sure that the surface was frighteningly hot. It was another five year’s before the Soviets’ Venera 3 became the first spacecraft to land on another planet. When it got to Venus, it radioed back “Yep. Hot,” and melted.

About two years later, in November 1964, a few months before Gus Grissom and John Young flew the first crewed flight of the Gemini program, Gemini 3, it was Mariner 4’s turn. It flew within about 10,000 km / 6000 miles of the Martian surface before cruising on by.

That was the first time we made it to Mars.

This time NASA/JPL sent along a camera:

The first close-up image of Mars, by Mariner 4 (from NASA)

After that, Mariner 10 reached the always difficult Mercury in March 1974 and flew within only 700 km / 450 miles! You read that right.

Poof, and just like that, hidden in the shadows behind Apollo, we’d made contact with the three nearest planets to Earth. These flights taught us more about planetary science, about orbital mechanics, and on it goes. We got scientific data, mapping, close photos. It was incredible.

These first interplanetary probes, the Mariner program, were eye-opening, stunning, and surprisingly long-lived; our first, wading tip-toes into the great cosmic ocean. Ten flights launched between 1962 and 1973, ending with Mariner 10. There were orbiters and flybys, and even two leftover probes that became part of another program. Which one? Tune in later this week.

All of it, though happened outside, and completely overlapping the Apollo program, which ended with Apollo 17 in 1972*. I wonder what it must have been like to be an engineer or a scientist working on Mariner in those days, hiding in the shadows.

So, here’s to tonight’s co-Number 5s! Mariner 2, Mariner 4, and Mariner 10!

Clear skies, everyone!

* Yes, there were the Skylab and Soyuz programs that used Apollo hardware and were related to Apollo, but they weren’t really part of Apollo proper.



  1. I’m not complaining, but this seems like cheating to list three for just one number/day. But that so cool. I had no idea all that was going on. I guess I need have to wait for the “Earth to Venus/Mars/Mercury” series to learn more. Ok, so get to it! (And thanks for cheating!)

    Liked by 1 person

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