- NASA’s Viking 1 lander launched on a 10-month journey to Mars on August 20, 1975.
- Viking was NASA’s first lander to carry instruments capable of doing chemical or physical analysis.
- Viking conducted experiments on the soil and took photographs while it was on the surface of Mars, then sent the data back to Earth.
In June, NASA made an exciting announcement; its Curiosity rover found organic molecules in rocks from Mars’ Gale Crater, and fluctuating levels of atmospheric methane that correspond with seasonal changes. It was an exciting step in answering a question that scientists have been researching for more than a century: Is there now, or has there ever been, any life on Mars?
The first step to answering that question on the surface of Mars actually began with the Viking 1 lander, which launched on a 10-month journey to Mars in August of 1975. While the experiments onboard the Viking 1 lander came back with different results from Curiosity, the lander paved the way for the future of scientific inquiry in space.
“Almost everything about Viking was the first time we had ever tried it,” planetary science and exploration curator Matt Shindell said. “NASA had never landed on another planet. They had never built a miniature laboratory. No one had ever built a computer that could withstand any of the stresses that Viking was under. The engineers had to design things that were never done before.”
Terminal Descent Engines
Landing a spacecraft on Mars is tricky because the atmosphere is thin; a parachute alone won’t slow it down enough. With the Viking Lander, a heat shield provided some initial deceleration. At an altitude of four miles, a parachute deployed. Once the craft was 3000 feet above the surface, the parachute detached and three descent engines were triggered to land the craft softly on Mars.
The shape of the engines, each with 18 small nozzles—reminiscent of a showerhead—is important, too. The Viking Lander was looking for signs of life on Mars. Scientists worried that by using one powerful engine to slow down the spacecraft, they might “sort of cook the dirt under the lander,” and kill off any potential living organisms, Shindell said. This engine design minimized that risk by spreading the exhaust over a wide angle.
Gas Chromatograph - Mass Spectrometer (GCMS)
The GCMS was one of the Viking Lander’s two main instrument packages, designed to look for signs of life. This was used to test soil samples for the presence of organic molecules—meaning, the products of life or the things that could sustain life. The Viking’s tests were negative. (As we know, the Curiosity rover’s testing this year yielded different results.)
The Viking Lander’s experiments wouldn’t have been possible without this robotic arm. The flexible metal piece was able to extend and contract—letting the Viking dig trenches, scoop up soil, and place the soil into the GCMS and biological experiments for testing.
This capability made the Viking unlike any other lander NASA had ever used before. The 1967 Surveyor 3 lander used a mechanical arm with a sample scoop to dig trenches and make piles of soil on the surface of the Moon, but the spacecraft didn’t carry any instruments capable of doing chemical or physical analysis. “The whole point of that experiment was just to dig the trenches and make the piles, then look at images from the television camera to see if you could extrapolate the mechanical properties of the soil,” Shindell said.
Viking was actually able to conduct experiments on the soil while it was on the surface of Mars.
Have you ever watched an older printer or fax machine print out something line by line as your message comes through? That’s how the Viking Lander’s camera worked. Inside this canister is a camera and a mirror. The mirror was able to pivot, while the camera stayed still and took “rapid fire” images. This allowed the Viking imaging team to take high-resolution images of select spots on Mars, and also to produce the first ever 360-degree panoramas of the Martian surface.
S-band High Gain Antenna
The Viking had two ways of sending data back to Earth. It could communicate with the Viking orbiter circling around Mars, which would then send a signal back to Earth. Or, if the location of the lander was on the side of Mars closest to Earth during its rotation, the Viking could use this antenna to send data back directly.
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