Countdown to the moon landing: Apollo 10 — the mission that came so close to the moon

This season we've been counting down to the 50th anniversary of the Apollo 11 moon landing. On July 20th, 1969, Neil Armstrong made his famous 'one small step' and became the first person to walk on the moon.  

And we've been looking at the earlier Apollo missions that paved the way to the moon.

Just two months before the historic landing, came what, for the astronauts involved, might have been the most frustrating mission of them all. Apollo 10 was the last mission before the landing, and it served as a complete dress rehearsal for one of the most historic moments of the 20th century.  It launched on May 18th, 1969, and did absolutely everything except actually land on the moon.  

Our guest for our retrospective on the run up to the Apollo 11 anniversary has been space enthusiast Amy Shira Teitel. Amy's a Canadian space flight historian, author, and host of her own YouTube channel 'Vintage Space'.

In this segment Amy and Quirks & Quarks host Bob McDonald talk about the mission that came within a mere 14 kilometres of the lunar surface.

This interview has been edited for length and clarity

Bob McDonald: As we travel back in time to 1969 moon landings only a couple of months away. But first there was Apollo 10. Let's talk about its objectives.

Amy Shira Teitel: Apollo 10 was really the dress rehearsal for the actual lunar landing, which makes it probably the most overlooked but most important mission that no one ever really gives any love.

Apollo 10 was the first time two spacecraft were going to be going to the moon. The first time they were going to be operating separately around the moon in the moon's environment. It was the first time all the communication systems would have to work, and not only that, it would actually go through all of the phases of a lunar landing. The lunar module would descend towards the surface then the ascent stage would separate to rejoin the command module in orbit. It was basically a moon landing without the landing.

Bob McDonald: Apollo 10 gets lost because there was a lot of talk about Apollo 8 which was the very first mission to the moon but that was only the command module. Apollo 10 was the first time that it was all up. Everything was included. All the equipment that was going to go to the moon was on Apollo 10.

They had funny names; Charlie Brown was the command module and Snoopy was the lunar module that went down towards the surface.

Bob McDonald: Apollo 10 did come very close to the moon, just nine miles or 14 kilometres away. Let's hear from a very excited Commander Tom Stafford and Lunar Module Pilot Gene Cernan aboard Snoopy.

Gene Cernan: Hello Houston, this is Snoopy, we is going, we is down among them Charlie (Duke).

Tom Stafford: Okay we'll be picking up our landing radar test and taking pictures here and it's a fantastic site.

Gene Cernan: It appears to be that in every fresh crater there are visible boulders both down in it, on the side and in the rim.

Tom Stafford: Also Charlie, it looks like we're getting so close, all we have to do is put the tail hook down and we're there (laughs).

Bob McDonald: Put the tail hook down, that's it. These guys are former fighter pilots that landed on aircraft carriers, and that's how they landed. They put a tail hook down to grab a cable. They felt they were so close to the moon they could have landed.

Amy Shira Teitel: Actually I found an interesting point of comparison. So nine miles is about 47,000 feet. A commercial flight is between 36,000 and 42,000 feet. So imagine looking down from the moon from a commercial plane, that's how close they were.

Bob McDonald: And when he says 'down among them' he meant down among the mountain peaks, they were flying through the valleys.

Bob McDonald: Apollo 10 did meet all of its mission objectives but this one thing we should talk about and that's something the astronauts themselves were reluctant to describe at first. Here's part of the conversation between Gene Cernan, who's in the lunar module with Tom Stafford, and John Young, the command module pilot. They're talking about eerie, musical sounds that they're hearing.

Tom Stafford: That music even sounds outer-spacey, doesn't it? Do you hear that, that whistling sound? Whooooo, it sounds like outer space type music.  

John Young: We'll have to find out about that, no one will believe us.

Bob McDonald: They were hearing a kind of musical sound up there going around the moon and NASA only posted that audio online just over 10 years ago even though it happened 50 years ago.

Amy Shira Teitel: First of all, I do love the very scientific explanation of the music as a 'whooooo' sound. I believe it happened on the far side of the moon which is important because there is no possible radio transmissions from Earth that you could get interfering with the signal between the two spacecraft on the far side of the moon. So what they think it actually was, was just the interference or the kind of feedback between the two spacecraft.

Bob McDonald: Now let's talk about Snoopy, the lunar lander, because there was recent news about possibly seeing it because they just discarded it after they finished with it.

Amy Shira Teitel: Which is such a lucky thing for future generations because most of the Apollo lunar landers were actually directed to smash into the moon for the sake of taking seismic measurements. But for Apollo 10, because they hadn't landed, there was nothing on the moon to measure the impact. So they just put it into orbit and there's always been this question of what happened to Snoopy.

Bob McDonald: So then Snoopy is still out there somewhere.

Amy Shira Teitel: It is. So instead of punting it towards the moon they actually punted it off into orbit around the sun which means that it's been out there for 50 years and amateur astronomers have been hunting for it and are really desperate to find it. It's such a cool thing to be out there and there's even some talk of if we could go visit it and see what happened to everything on board, which is really just a bunch of trash and human waste and stuff which is not necessarily something you want to recover.

I think it was Gene Cernan who joked that there's probably enough biological material onboard to bring the crew back to life. So gross and so funny. But as recently as last week there was another sighting. Astronomers are quite sure that they've found Snoopy.