Lauren Fuge
NASA’s InSight mission has successfully touched down on Mars after a harrowing entry into the atmosphere.
Hundreds of scientists, engineers and technicians on Earth were biting their nails as they waited to hear news about the carefully-choreographed last leg of the spacecraft’s journey. They then erupted into cheers and whoops as landing was confirmed.
This isn’t NASA’s first rodeo – the agency landed the twin rovers Spirit and Opportunity perfectly in 2004, followed by the Phoenix lander in 2008 and rover Curiosity in 2012. But the team was still on tenterhooks as this new lander hurtled down into the Martian atmosphere, carrying out a series of pre-programmed last-moment manoeuvres.
“It takes thousands of steps to go from the top of the atmosphere to the surface, and each one of them has to work perfectly to be a successful mission,” explains Rob Manning, chief engineer at NASA’s Jet Propulsion Laboratory (JPL) in California.
The US$850 million dollar lander hit the atmosphere at a perfect 12-degree angle. Any steeper and it would have burned up; any shallower and it would have effectively bounced off.
As it moved downwards, the lander’s hefty heat shield withstood two minutes of 1000 degree Celsius temperatures, dropping its speed from a harrowing 20,000 kilometres per hour to 8000.
The lander then deployed a durable parachute to decelerate further, jettisoned its heat shield, and finally used braking rockets for the descent.
At the very last second, the rockets were cut – dropping the lander, intact and successful, on a vast and desolate plain.
“There’s a reason engineers call landing on Mars ‘seven minutes of terror,’” says Rob Grover, InSight’s entry, descent and landing expert at JPL.
Now, it’s time to get to work.
Unlike Curiosity, which is currently trundling around on six sturdy wheels, InSight’s landing spot is its final destination. This three-legged lander will set up shop exactly where it is, using custom-made instruments to study the deep interior of the planet.
InSight (short for Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport) aims to understand the formation, evolution and composition of Mars.
“Previous missions haven’t gone more than skin-deep at Mars,” says Sue Smrekar, the InSight mission’s deputy principal investigator at JPL. “InSight scientists can’t wait to explore the heart of Mars.”
The lander will map the interior of the planet by measuring marsquakes, explore its geological evolution by measuring heat output, track the “wobble” of the planet around the Sun and thus learn about its core, and also search for liquid water, meteorite impacts, volcanic plumes, and more.
By learning more about Mars’ interior, InSight will enable a better understanding of what was going on in the solar system 4.5 billion years ago, when planets were forming out of a dusty ring around the Sun.
As Australia’s University of New South Wales astronomer Kirsten Banks points out: “Not only will it give us an insight (I make no apologies about the pun) into the inner workings of Mars, it will also help us understand the formation and evolution of other terrestrial planets.”
InSight will also hopefully find out how Mars went from being a warm, wet place to the dry, freezing one it is today.
“It’ll be really interesting to see the degree to which Mars is still active, and how hot its interior still is,” adds Jonti Horner, astrophysicist from the University of Southern Queensland in Australia. “Has the planet frozen through to the core, or is there a kernel of warmth and activity left in it?”
These answers may also shed light on the formation of life on Earth – and, perhaps, on Mars.
The first results are expected in about three months.
Astronomers around the world are excited to see the data that InSight will gather. These include the only Australian involved in the mission, Katarina Miljkovic, a planetary scientist at the newly-formed Space Science and Technology Centre at Curtin University in Western Australia.
“My role is to study marsquakes that originate from meteoroid strikes on the ground and fireballs bursting in the atmosphere,” she explains.
By combining numerical simulations of impact events with data from InSight, Miljkovic and her team hope to learn more about Mars’ crustal properties.
But the successful landing of InSight wasn’t just about the lander itself; it was also a test of new satellite technology. When the mission launched in May this year, it wasn’t alone – two CubeSats tagged along. These miniature satellites are the first of their kind to ever journey into deep space.
Shortly after taking off from Earth, the CubeSats deployed and travelled on their own trajectory to Mars. But as InSight entered the Martian atmosphere and made its epic landing, they were in position 3500 kilometres above the planet to witness the event and relay that data back to Earth at the speed of light, meaning that the team back home knew the outcome within eight minutes.
Without these little satellites, affectionally nicknamed Eve and Wall-E, the team would have had to wait several hours for the data to be relayed through NASA’s Mars Reconnaissance Orbiter and Mars Odyssey.
Now, Wall-E and Eve will go on to orbit around the sun for eternity, while the Mars Reconnaissance Orbiter will take over to beam back InSight’s data.
InSight itself is planned to run for two years. But with Curiosity still trucking four years past its original mission’s end date, only time will tell how much science we’ll get out of this hardy little lander.
