This week on Quirks & Quarks we are devoting the entire episode to the question, "Should humans be in space?"

It's an interesting debate about whether robots are a better way to explore other worlds. But in reality, it is not a case of either/or. We need both.

As the world prepares to celebrate the 50th anniversary of the first humans to walk on the moon this July 20th, little mention will be made of the robots that went there first. Neil Armstrong and Buzz Aldrin would not have been able to take those first steps had it not been for a fleet of robotic probes that flew to the moon ahead of time to survey the lay of the land and identify the best places to touch down.

Robotic spacecraft play a crucial role in exploration

Probes such as Surveyor landed on the surface and showed that the ground was hard enough to support a spacecraft. One fear at the time was that after billions of years of bombardment by objects from space, the surface of the moon would be pulverized into a fine powder so deep it would completely swallow any craft attempting to land there. Surveyor's footpads barely sunk into the surface, showing that the dust was not as deep as the scientists feared.

The main objectives of the Surveyors were to obtain close-up images of the lunar surface and to determine if the terrain was safe for manned landings. This image shows a view of the footpad of Surveyor 5 on the moon. (NASA)

The Russian Lunokhod rovers, about the size of a bathtub, became the first vehicles to drive on the moon, a feat that the Americans took to the limit in later Apollo missions as they drove their two person lunar rover across the surface like a dune buggy.

When it comes to space exploration, the robots do the early reconnaissance and the primary science. They fly past planets for the first time just to see what's there. Then orbiters map the surface followed by landers — when possible —that actually touch it. Robots have not only been to the moon, but have explored every planet in our solar system.

The Soviet Lunokhod rovers were about 2.3 meters long and 1.5 meters tall. (NASA)

Human missions are the ultimate human adventure

The human missions are mostly about pushing the limits of human endurance, where well trained, physically fit astronauts and cosmonauts tolerate the stresses of launch and landing, the negative effects of prolonged weightlessness, and the risks inherent in living in an extreme environment. It is the ultimate human adventure, one that provides real role models for young people and demands the highest technology to keep those people safe up there. It is also much more expensive.

The human-robot partnership in space is similar to hunters with dogs that run ahead to locate prey. The robots race ahead to sniff out the territory, identify the most interesting sites and sample the soil, then the humans follow.

If and when we discover life in our solar system

A big quest in space exploration is the search for life. If robots do find life on Mars, or in the ice moons of Jupiter and Saturn, that may actually prevent humans from going any father. The presence of alien life raises a huge issue of cross-planet-contamination. Protocols are already in place for planetary protection, where spacecraft destined to land on Mars are sterilized to prevent Earthly microbes from spreading on the red planet. Martian microbes may not have any resistance to our alien invaders, so we could inadvertently cause a local die off similar to the European explorers who brought disease to North American Indigenous people.

NASA's Mars Exploration Rover Spirit acquired this image in 2007. The mosaic shows an area of disturbed soil made by Spirit's stuck right front wheel. (NASA/JPL-Caltech/Cornell)

Sending people to Mars makes the matter more serious. Humans are very dirty beasts. We are constantly shedding waste products from our bodies, our breath, our food, anything we touch. It would be next to impossible to send humans to Mars without contaminating the environment with microbes.

Martian life forms could be devastated by a human sneeze, which is exactly what happened in the fictional story, War of the Worlds, where invincible Martians that were devastating the Earth, ultimately fell prey to the common cold. A humble virus took down high technology alien invaders. We do not want to become the invasive species that wipe out life on other planets, or worse for us, become contaminated by alien organisms for which we have no resistance.

In this July 20, 1969 file photo, Astronaut Edwin E. Aldrin Jr., lunar module pilot, is photographed walking near the lunar module during the Apollo 11 extravehicular activity. (The Associated Press)

That's one reason the quest to find life on other worlds is so important. If it is found, perhaps those worlds will become off limits for humans, so exploration will only be carried out through intelligent robots while humans ride along through virtual reality back on Earth.

Either way, our thirst for new knowledge and natural urge to explore is carrying us across our solar system. And as we venture further out to fascinating new places, accompanied by our robotic companions, perhaps the biggest lesson we will learn, as we did from the Apollo moon missions, is what we see when we look back at home, back to a small, beautiful and precious blue planet, the blue marble, the crown jewel of the solar system.