By Mary O’KEEFE
Curiosity is getting closer to its landing on Mars.
In a little over six weeks, the Mars Science Laboratory named Curiosity will be entering the Martian atmosphere where it will land on the surface of the red planet.
“The flight is a little more than half way to Mars,” said Jordan Evans, leader of the engineering operation team for the Mars Science Laboratory at the Jet Propulsion Laboratory. The science laboratory that launched on Nov. 26, 2011 is scheduled to land on Aug. 5 at 10:32 p.m. (PDT).
“The landing target ellipse had been approximately 12 miles wide and 16 miles long (20 kilometers by 25 kilometers). Continuing analysis of the new landing system’s capabilities has allowed mission planners to shrink the area to approximately four miles wide and 12 miles long (seven kilometers by 20 kilometers), assuming winds and other atmospheric conditions are as predicted. Even with the smaller ellipse, Curiosity will be able to touch down at a safe distance from steep slopes at the edge of Mount Sharp,” according to JPL.
The spacecraft carrying Curiosity has had a few trajectory adjustments along the way. The engineers did have one problem with the computer early in the flight that prevented them from going into an autonomous mode, however that was corrected.
Well before the spacecraft was launched, engineers had gone over every scenario they could imagine that both the spacecraft and science rover could face.
“We look at not only what the likelihood is of the [scenario] happening but how to deal with the consequences,” Evans said.
Practicing “what if” scenarios continue throughout the duration of the project – before launch and during the flight, the landing and the science mission.
“Even last week we had a series of risk reviews for driving [the rover] around,” Evans said.
Curiosity’s landing will be different than those of the recent JPL family of rovers. The most recent rovers, Spirit and Opportunity, landed nestled in a series of inflated balloons. This time a sky crane will be used, allowing the spacecraft to lower through the atmosphere using a parachute and thrusters to control its speed and direction.
“It will all be autonomous,” Evans said.
Although JPL engineers and scientists have successfully landed on Mars several times in the past, each landing has its “holding your breath” moments.
“We will hold our breath beyond the sky crane landing,” Evans said.
He added that once the spacecraft separates from the landing vehicle it will hit the atmosphere at about 13,000 miles per hour.
“Unlike the other rovers, [Curiosity] is more like a space shuttle. It flies and makes a series of ‘S’ turns to the target site,” he said.
All of this is entrusted to the computers.
It takes almost 14 minutes to relay information from Mars to Earth. The entire landing is expected to take about seven minutes so autonomous is the only way for it to land.
A relay operator will be listening to tones of what mode the rover is in and what is happening once the rover deploys its system. Once it senses touch down, cuts the umbilical cord from the landing spacecraft to the rover, is at zero velocity and at rest, “then the team can breathe a sigh of relief,” Evans said.
Once it lands it will begin its scientific mission. The rover’s first goal is to climb Mt. Sharp, a mountain three miles tall. When that will happen will be determined by the science around the rover at the time of landing. There may be something interesting at the landing site scientists that engineers will want to explore before their first rolling journey begins.
Speaking with Evans, it is obvious he loves his career. He said he had always dreamed of working in the space industry, which he considers a mix of science and imagination, combined with new engineering challenges.
“It is like working at Disneyland,” he said.