The landing on Mars was a nagging point for Redmond engineers

At Aerojet Rocketdyne in Redmond, who made the rocket engines for NASA's last Mars mission, the last "seven minutes of terror" as the lander was heading to the surface was familiar, but remained intense.

In each mission to Mars, there is what the engineers call the "seven minutes of terror".

That's about the time it takes from the moment a spaceship enters the Martian atmosphere at a speed of about 20,000 km / h until it lands on the red planet.

And during these seven minutes, the inhabitants of the Earth have only to wait and hope.

For the engineers and other employees of Aerojet Rocketdyne, a rocket engine manufacturer for Redmond's latest NASA Mars mission, the seven minutes arrived just before midday on Monday.

"My heart was pounding," said Aerojet Rocketdyne's InSight Chief Engineer Matt Dawson as he stood in the back of the company's auditorium.

A few hundred Dawson colleagues had already gathered enthusiastically in the room, staring at two giant screens for the live video of the mission control mission at the Jet Propulsion Laboratory in Pasadena, California.

[Related: ‘Flawless’: NASA craft lands on Mars after perilous journey]

Six months ago, the spacecraft the size of a golf cart had been launched in space from Vandenberg Air Force Base in California. Now, after traveling nearly 300 million miles, the ship was making its final approach.

Under the eyes of Dawson and his colleagues, the ship plunged into the low Martian atmosphere and began a combination of maneuvers (separation of her heat shield, deployment of a special parachute and carefully synchronized impulses from the rocket engines ) aiming to slow the ship from its interplanetary pace to the speed of a jogger back to Earth.

The atmosphere in the room was tense. Although Aerojet Rocketdyne is a veteran of many landings of this type – the company has participated in seven successful American missions on Mars, starting with the Viking mission in 1975 – this last step is just as painful.

"During these seven minutes, 15 events must unfold sequentially, all without fail," said Rob Dooley, a 53-year-old project manufacturing engineer, while standing at the # 39, back of the auditorium and watched live images of JPL. . "And our downhill engines are the last ones."

And probably the most important. Various Aerojet Rocketdyne engines are present at each stage of the InSight mission, from take-off to landing: "The road to Mars passes through Redmond," commented Ken Young, the company's chief operating officer in Redmond. But it is the descent engines that determine whether the multi-year mission, whose objective is to measure and map underground Mars, reaches the Red Planet in working condition.

As the spacecraft falls about 1 kilometer above the Martian surface, the 800-pound landing gear must separate from its outer aerodynamic hull and fire its 12 engines. Over the next few seconds, these engines move the undercarriage to the touchdown position and slow down the undercarriage so that the final impact can be absorbed by its three spring-loaded legs.

These maneuvers can not be controlled from Earth in real time. Mars is so far away that Earth's radio signals take eight minutes to reach the spacecraft, which is too much of a delay for such a delicate operation. Instead, the maneuvers are all preprogrammed in the flight controls.

And sometimes these programs do not work. Most of those present on Monday in the auditorium were probably very aware of the bad Mars Schiaparelli Mars of the European Space Agency, which crashed on October 19, 2016, three minutes after touching the airspace. Martian atmosphere, because of a data problem.

Which means that people like Dawson and Dooley can only watch and wait. "It's a bit scary," Dooley admitted.
Indeed, as the Mission Control technician began to tell the final stages of the landing process, the atmosphere in the room became sharply tense.

Around 11:53, the lander crossed the kilometer mark. While the onboard radar was locked to the surface, the landing gear separated from the shells and the 12 engines started.

"These are our engines," exclaimed Dooley, to a relieved laugh.

A few seconds later, Mission Control started the countdown at high altitude, with a fast, rhythmic shot.

"Six hundred meters."

"Three hundred meters."

"Sixty meters."

The numbers began to arrive more quickly. The room is killed.

"Fifty meters. Constant speed.

"Twenty meters."

"Seventeen meters. Waiting for a touchdown. "

So … nothing. The AP is killed. The room was so quiet that the engineers were breathing. The seconds passed with agonizing slowness.

Finally, 15 seconds later, the Mission Control Technician said, "Touchdown confirmed." The room broke under applause and applause.

Moments later, after most of Aerojet Rocketdyne's employees returned to work, Dooley and Dawson stood at the back of the room and talked about this seven-minute edition of terror.

The two men made fun of their own nervousness. But both were clearly relieved, even though they knew the relief was only temporary: Aerojet Rocketdyne is taking part in another Mars 2020 Rover mission from NASA.

As Dooley says, "We'll be back here in two years to start over."

In the coming months, InSight will begin its study of the Martian hell with the goal of helping scientists understand the structure of the planet, lessons that could also help illuminate the origins of the Earth. He will listen to the tremors (marsquakes) and collect data that will be collected in a map of the interior of the red planet.

InSight landed at Elysium Planitia, near the equator in the northern hemisphere. Scientists at the mission described the area as a parking lot or "Kansas without corn".

Its main mission on the surface is to last almost two years. He will try to answer various questions: how often does the ground tremble with marsquakes? What is the size of the molten core within Mars? What is the thickness of the crust? How much heat comes from the disintegration of radioactive elements in the heart of the planet?

InSight contains two main instruments: a dome-shaped box containing seismometers and a thermal probe that must widen to a depth of about 16 feet. NASA spent $ 814 million for InSight. In addition, France and Germany have invested $ 180 million to build these key instruments.

Seismometers, designed to measure surface movements less than the width of a hydrogen atom, will essentially produce sonograms of the interior of the planet. Scientists are looking to record at least 10 to 12 Marchquakes over two years.

The landing of InSight was not the only success of NASA on Monday. The agency used this mission to test new technologies.

Two identical spacecraft, christened Mars Cube One, or MarCO, were launched with InSight in May. MarCO A and B then separated from InSight's cruise stage and remained behind.

Hundreds of miniature satellites called CubeSats have orbited the Earth in recent years, but this is the first time that CubeSats has been sent on an interplanetary voyage.


Local space contractors cross a new frontier (2015)

The NASA Insight mission according to The Oatmeal

Read more and listen to podcasts on the Mars InSight mission on the NASA website »

The New York Times contributed to this report.

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