Last month, British amateur astronomer Nick Howes embarked on a mission to find Snoopy. He's not looking for a cartoon Beagle swirling through space in a cosmic dogfight with the ghost of the Red Baron. He's looking for Apollo 10's lunar module, nicknamed "Snoopy," which is believed to be in an orbit around the sun, and is the only remaining intact lunar module in the galaxy.
Howes came up with the difficult task after he helped school-aged children discover comets and asteroids using data from the twin Faulkes telescopes that are located in Australia and Hawaii. To find new heavily bodies, astronomers compare images from telescopes. As ancient astronomers observed, stars don't move, not noticeably, but they look different depending on where you are on the planet. They are relatively stationary points in the sky. Comets, asteroids, and planets stand out because they are moving relative to those "fixed" stars.
The astronomer's principle tool for finding new bodies in space is a blink comparator, a machine that allows astronomers to rapidly shift back and forth between two images of the same part of the sky taken days or weeks apart. Blink comparators used to be a manual devices, alternately shining a light behind two different images; modern astronomers have the luxury of computer software that shifts between images for them.
When comparing two images, the stars as fixed points will be in the same place. Anything that isn't a star, however, will be in a different position in two images and therefore creating the illusion of movement. Astronomers can then track a moving dot through a number of images, do a bunch of math that I can't explain, and ultimately determine what exactly the object is that they've found and plot its orbit.
A blink comparator is how Clyde Tombaugh found Pluto, painstakingly and manually flipping between two images at a time at the Lowell observatory in Flagstaff, Arizona. This is also how Mike Brown found a trans-plutonian body in California, ultimately leading to Pluto's demotion from planet to a dwarf planet. And this is how Howes intends to find Snoopy.
It seems like a horribly daunting task, comparing images of the night sky two at a time to find some evidence of a moving object that's the size of a small car. Luckily, Howes won't be searching for a needle in a haystack. A closer analogy would he that he'll be searching for a needle in a bucket of hay.
Apollo 10 Showed Us We Could Do It
Apollo 10 was a dry run for Apollo 11's lunar landing. The mission, which launched on May 18, 1969, was the first complete flight on an Apollo spacecraft outside of Earth's orbit. Apollo 8 went to the moon without a lunar module (LM) and Apollo 9 tested the whole spacecraft (LM and command and service module or CSM) in Earth orbit.
The mission was a vital step leading up to a manned landing. Scientists and engineers had designed the mission based on their knowledge of the moon's gravity and orbital mechanics, but Apollo 10 was the first time their work would be tested. And men's lives were on the line. This was the moment to find out whether their calculations on translunar trajectories were correct, if stellar navigation was an adequate system in deep space, the chance to check and refine the Earth-based spaceflight tracking techniques, to check out the flight paths and radar information that were preprogrammed into the LM's computer, and finally to see if the lunar flight control systems worked as planned. With so much on the line, this was a make or break mission for the biggest, wildest technological effort in American history.
Apollo 10 entered into lunar orbit getting as close to 60 miles above the surface. Tom Stafford and Gene Cernan in the lunar module (which was nicknamed Snoopy after the Snoopy-esque linings that the astronauts wore under their helmets) separated from John Young in the command module (which was called Charlie Brown), and moved towards the surface in a low lunar orbit. At their closest point, they came within 9 miles of moon rocks. After a brief period in this low orbit, Stafford and Cernan fired Snoopy's ascent engine, met Young in orbit 60 miles above the surface, and the crew performed the first rendezvous and docking of two vehicles around the moon.
Every move on this mission was critical. The crew and the spacecraft, performed flawlessly. NASA was ready to land on the lunar surface, which it did with Apollo 11.
What happened to Snoopy
After their successful rendezvous in lunar orbit, Stafford and Cernan transferred from Snoopy back into Charlie Brown. With all three men settled in their return spacecraft, they closed the hatch between the LM and CSM and separated, leaving Snoopy to die in the cold of space. The craft had no purpose beyond the dry run for a landing. and it wasn't equipped to come back to Earth. For 239 seconds, flight control fired Snoopy's ascent engine to full depletion, using up all of its available fuel. This sent the spent lunar module into an orbit around the Sun. The crew watched Snoopy gain speed and drift into black eternity.
With Snoopy's portion of the mission complete, Stafford, Cernan, and Young went back to tracking landmarks on the moon's surface. Their survey lasted 31 lunar orbits, after which they fired Charlie Brown's main engine to return home.
Neither the crew nor NASA paid attention to Snoopy's fate after the jettison. NASA does, however, know where and when the LM separated and how fast the spacecraft was going. With this data, Howes can calculate its rough orbit and effectively shrink the area where the hunt for Snoopy will take place.
Nevertheless, it's still a hard task, one that may even invite comparisons to the Apollo program itself. Apollo was more than anything else a feat of clever engineering and creative problem solving. The hunt for Snoopy promises to be the same. It will take the unrelenting drive and creativity of Howes and his team to sift through thousands of images. Gathering the images will push modern astronomical technology to its limits much in the same way Apollo pushed the envelope on the technology of the 1960s. Snoopy's size is what makes this a technical challenge – it will take extremely refined instruments to find the small LM. Kennedy promised a moon landing, to paraphrase, not because it was easy, but because it was hard. The hunt for Snoopy, with its Apollo-era resolve, is the same.
Then again, in 1969, the United States landed on the moon, achieving what many still say is humanity's greatest engineering achievement; sometime soon, a British citizen may discover a famous artifact, or space trash, if you like, as it hurdles aimlessly through the solar system, carrying the memory of a cartoon dog. The symbolism is also cartoonish.