At Aerojet Rocketdyne in Redmond, which made the rocket motors for NASA's last mission to Mars, the last "seven minutes of terror" when the vehicle heading to the surface were familiar, but still intense.
In each mission to Mars, there is what the engineers call the "seven minutes of terror".
That's roughly the time it takes from the moment a spacecraft enters the Martian atmosphere at about 12,000 mph to the moment it lands on the Red Planet.
And during those seven minutes, there is nothing that people on Earth can do but wait and wait.
For engineers and others at Aerojet Rocketdyne, based in Redmond, creators of rocket engines for NASA's last mission to Mars, those seven minutes arrived shortly before noon on Monday.
"My heart was just pounding," said Matt Dawson, 45-year-old chief engineer of the InSight project at Aerojet Rocketdyne, as he was near the back of the company's auditorium.
Moments earlier, approximately 100 of Dawson's colleagues had enthusiastically entered the room, their eyes riveted on two large screens with live video of mission control at the Jet Propulsion Laboratory in Pasadena, California.[Related: ‘Flawless’: NASA craft lands on Mars after perilous journey]
Six months earlier, the ship the size of a golf cart had been launched into space from the Vandenberg Air Force Base in California. Now, after traveling almost 300 million miles, the ship was making its final approach.
While Dawson and his colleagues watched, the boat plunged into the thin Martian atmosphere and began a combination of maneuvers (separation of its heat shield, deployment of a special parachute and carefully timed pulses of the rocket motors) to reduce the speed of the ship. Interplanetary rhythm at the speed of a corridor on Earth.
The atmosphere in the room was tense. Although Aerojet Rocketdyne is a veteran in many of these landings (the company has participated in the seven successful missions from the United States to Mars, beginning with the Viking mission in 1975), this final stage is just as unbearable.
"In those seven minutes, there are 15 things that have to happen, sequentially, and all without failures," said Rob Dooley, 53, the project's manufacturing engineer, as he stood near the back of the auditorium and watched the broadcast. live from JPL. "And our downhill engines are the last."
And possibly the most important one. Several Rocketdyne Aerojet engines appear at every stage of the InSight mission, from takeoff to landing: "The road to Mars goes through Redmond," said Ken Young, general manager of Redmond's operations. But it is the descent engines that determine whether the multi-year mission, which aims to measure and map an underground Mars, reaches the Red Planet in working conditions.
As the spacecraft drops about 1 kilometer above the Martian surface, the 800-pound landing module must be separated from its outer aerodynamic cover and its 12 engines powered. During the following seconds, these engines maneuver the landing module in a contact position and reduce the speed of the lander 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 it would take eight minutes for the radio signals from Earth to reach the ship, a delay too great for such a delicate operation. Instead, the maneuvers are preprogrammed in the flight controls.
And sometimes, those programs do not work. Most of the people in Monday's audience were probably very aware of the terrifying terrifying Schiaparelli Mars of the European Space Agency, which crashed on October 19, 2016, three minutes after it reached the Martian atmosphere, due to a failure in the data.
All of which means that people like Dawson and Dooley can only watch and wait. "It's a bit stressful," Dooley admitted.
In fact, when the Mission Control technician began to narrate the final steps of the landing process, the mood in the room became palpable.
Around 11:53 a.m., the lander reached the 1 kilometer mark. When the on-board radar was fixed on the surface, the lander was separated from the carcass and all 12 engines were turned on.
"Those are our engines," Dooley shouted, with a very relieved laugh.
Seconds later, the Mission Control began the countdown of altitude, in a fast rhythmic fire.
Six hundred meters
"Three hundred meters."
The numbers began to arrive faster. The room was silent.
Fifty meters. Constant velocity."
"Seventeen meters. Waiting for a touchdown. "
Then nothing. The PA was silent. The room was so quiet that you could hear the engineers breathing. Seconds past with agonizing slowness.
Finally, 15 seconds later, the control technician of the Mission said: "Confirmation of confirmed contact". The room erupted in applause and shouts.
Moments later, after the majority of Aerojet Rocketdyne employees returned to work, Dooley and Dawson stopped at the back of the room and talked about this seven-minute horror edition.
Both men laughed at their own nervousness. But both were clearly relieved, although they knew the relief was only temporary: Aerojet Rocketdyne is involved in another mission, NASA's Mars 2020 Rover.
As Dooley says: "We'll be back here in two years, doing it again."
In the next few months, InSight will begin its study of the Martian underworld, with the goal of helping scientists understand how the planet was formed, lessons that could help shed light on the origins of Earth. You will hear the tremors (marsquakes) and collect data that will join a map of the interior of the red planet.
InSight landed on Elysium Planitia, near the equator in the northern hemisphere. Mission scientists have described the region as a parking lot or "Kansas without corn."
Its main mission on the surface is to last almost two years. It will try to answer a variety of questions: How often does the soil tremble with the marsquakes? How big is the molten core inside Mars? How thick is the crust? How much heat flows from the decomposition of the radioactive elements in the core of the planet?
InSight carries two main instruments: a dome-shaped package containing seismometers and a heat probe that is buried approximately 16 feet down. NASA has spent $ 814 million on InSight. In addition, France and Germany invested $ 180 million to build these major instruments.
Seismometers, which are designed to measure surface movements less than the width of a hydrogen atom, will produce what are essentially sonograms of the entrails of the planet. In particular, scientists are looking to register at least 10 to 12 marsquakes in two years.
The landing of InSight was not the only success of NASA on Monday. The agency used the mission to test new technologies.
Two identical ships known as Mars Cube One, or MarCO for short, were launched with InSight in May. MarCO A and B separated from the InSight cruising stage and have since lagged behind.
Hundreds of miniature satellites known as CubeSats have been launched into orbit around the Earth in recent years, but this is the first time it has been sent to CubeSats on an interplanetary voyage.
The New York Times contributed to this report.