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By Denise Chow
When its Curiosity mobile landed on Mars in 2012, NASA called the last phase, the most perilous of its descent, "seven minutes of terror".
Now, the landlord Mars InSight of the space agency is a day away from his touch, slightly more compressed, on the red planet. This time, NASA announced that the final phase of the landing of the spacecraft would last about six and a half minutes – and that the InSight team members are trying to contain their growing anxiety .
"It's a little less terror," jokes Rob Grover, who leads the team responsible for landing InSight at NASA's Jet Propulsion Laboratory in Pasadena, California.
InSight, which is designed to study the deep interior of the red planet, is expected to land on the Martian surface on Monday around 3 pm. EAST, having traveled more than 300 million kilometers since its launch in May from Vandenberg Air Force Base in California.
Grover is a veteran of three other landings on Mars. He was one of the teams that placed Spirit and Opportunity twin on the Martian surface three weeks apart in January 2004 and again when the Phoenix Phoenix Lander touched down in 2008.
Recently, NBC News MACH talked to Grover about what worries him most about the landing, comparing the InSight mission to previous trips to Mars, and how he and his colleagues keep their cool. in Mission Control.
This interview has been modified for clarity and brevity.
MACH: How do you feel now that the day of landing is imminent?
Grover: The team feels very good. We did everything we could to make sure we were successful. Of course, there is nervousness and excitement, and as we get closer, it starts to grow. But we feel good about it.
What is the landing process?
To date, all our landers on Mars have used a landing architecture similar to that of the Viking missions that landed in the 1970s. There are some differences in the design of the LG itself, but all penetrate into the atmosphere of Mars with an airgel. And the aerosols we used are very similar in design: they are simply bigger or smaller.
The InSight aeroshell is identical to the Phoenix aeroshell, except that it has a slightly thicker heat shield. It's the same size and looks a lot like the Spirit and Opportunity aeroshells and even Pathfinder. So we know very well how these capsules fly in the atmosphere of Mars.
So we enter the atmosphere of Mars and about 99% of our speed is burned or reduced as we fly into the atmosphere in the aeroshell. All our missions are then transformed into a parachute, usually about twenty kilometers from the ground. And we use the parachute to do a good part of the rest of the slowing down of the vehicle. For InSight, we go from 12,300 miles to the hour at the top of the atmosphere at 5 miles to the touch time, so the system is designed to eliminate all that speed. Landers that use rocket power for the remainder of the descent generally separate from the parachute to nearly a kilometer or less, then perform the rest of the landing with rocket power. InSight has three landing legs, so we land like a traditional landing gear landing gear.
How do you make sure that InSight is recovering?
While descending under the effect of the power of the rocket, 12 engines are grouped in groups of four, at the bottom of the lander. These rocket engines carefully keep the undercarriage steady as it descends, so they slow down a bit to make sure the undercarriage is horizontal and balanced. And then, when we touch the ground, the feet of the lander have a switch at the top and when the effect touches the surface, it triggers this switch that automatically turns off the engines immediately. One leg touches the surface to turn off the engines. And we are doing this so that the engines do not continue to turn after the landing, as this could cause problems and cause the flip of the undercarriage, which would be bad.
When will you know if InSight has landed successfully?
Since Mars is so far away at the time of landing, the data and signals that the lander is returning to Earth will take a little over 8 minutes to reach Earth. All landing, from the top of the atmosphere to touchdown, takes about six and a half minutes. Therefore, when we receive signals, the undercarriage will already be on the surface. But we will look at these data as if they were happening then.
How do you and your colleagues keep calm in Mission Control?
JPL has a tradition of circulating a pot of lucky peanuts, which goes back to the 1960s. This is one of our traditions and it keeps the light. Certainly, hearts will beat the pace at the touch of the atmosphere and the beginning of the landing, but that's part of the job.
What will your schedule be like before landing?
Our day-to-day operations are very similar until the night before. Our main task currently is to take the latest weather forecast for the landing – we have a team of atmospheric scientists using the [Mars Reconnaissance Orbiter] Spaceship to observe the atmosphere and provide forecasts on the atmosphere that will take place on Monday when we land. We take this information, as well as the most recent information from our navigators on their thoughts on the trajectory for arrival on Mars, and we evaluate and make small adjustments to the software parameters that are on board the spacecraft that will control. the landing gear on landing. We do it every day in a repeated cycle to get an update of the atmosphere and a trajectory.
We have the ability to change the software parameters onboard the sensor until one and a half hours before landing. So we're going to look at that and decide if we want to make a final adjustment to the landing. This weekend, we will be doing it 24 hours a day, so we will be doing 24 hour operations starting on Saturday morning until the landing.
Once the landing sequence has begun, is it simply hoping for the best?
It is totally true. Because of the 8-minute travel time for the signal to Mars and then back – it would be a total roundtrip of 16 minutes – it is not possible to manipulate the probe and fly away from the Earth. The landing must be fully automated and controlled by the computer aboard the lander, this is one of the challenges. Once we have defined these last parameters and the sequence is in progress, we are watching some aspects, like everyone else, because we can not do anything once the landing has begun.
What is it that worries you the most about the InSight Landing?
I think we need to make sure that everything goes well with the plan of operations and that we do everything we need and have it all completed in time for this last update of the parameters. We have repeated this repetition three times in the last nine months. We repeated hour by hour the last five days before landing. So we really ended this week three times. We are in good shape and the team is well done and runs very well.
It's hard to land on Mars. It is always possible that we have a bad day or that the environment of Mars differs a bit from what we had planned and conceived for years. It's both stressful and exciting, mixed.
What is the riskiest part of landing?
A few times in the control room, we will be particularly happy to see the landing unfold. One of them is the parachute deployment. The parachute is not inherently very risky. But rather than being a rigid model like the metal undercarriage, which is very predictable, it is nylon. This is what we call a sweet good. And when we deploy that, it's a little less predictable. Although we have had great success using parachutes on Mars, and hopefully again, this is one of those times when we will be happy to release it and we know we are descending under the parachute .
I think another problem is that the radar needs to work properly in order to land. We have radar antennas under the undercarriage. While the lander navigates from the top of the atmosphere, it is not precise enough to know exactly where the ground is. So we need the radar to give us new information on our height above the ground and the speed at which we descend. . Without radar, we do not have enough information to land successfully. Once the radar has conquered the ground, it will be another time we breathe a sigh of relief.
Have valuable lessons been learned from evil missions on Mars?
After each of our missions that we send to Mars, we always perform what we call an EDL reconstruction, where we take all the landing data and basically establish the precise trajectory of the landing, its behavior and the behavior of the flight software. We pass this on to future missions, so we accumulate better information on how to succeed on Mars.
This particular lander is almost a carbon copy of the Phoenix landing system. The design is related to Mars Polar Lander, which, if you know your landing history on Mars, did not experience success in the late 90's. We had no real-time communication when of this landing. So we do not know exactly what happened to Mars' polar Lander, but this triggered a very detailed review of the design, and some potential failure mechanisms were discovered. . This really helped to design the Phoenix Lander, which was also built into our LG. This is an example of how we used the information collected during the previous mission to reinforce the next mission.
Does InSight landing site pose any particular problems?
The landing site can be one of the safest on Mars. It's one of the flatest places on Mars and its rock level is very low. These are two things, from the point of view of landing safety, that we are looking for. On these two points, it's a very safe place. Our project manager likes to say that we are landing on the Kansas of Mars.
Once InSight appeared and you had the opportunity to catch your breath, what do you expect most from this mission?
Doing a mission on Mars is a little magical. Once we have discovered the scientific instruments and started to learn more about Mars, it will be really cool to discover things about the unknown. It's a big part of contributing to a mission like this. Believe it or not, the landing team is usually prepared about a week after landing. We will not participate in any of the surface operations.
Will you be involved with the NASA rover 2020?
I do not know where I'm going to make the transition once InSight is done. We will see what the future holds for us.
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