Mars InSight (artist's impression)

Nasa spacecraft has Mars landing ‘InSight’

Image credit: Nasa

Nasa's InSight spacecraft is due to land on the surface of Mars today, completing its seven-month journey to the Red Planet.

Having travelled for over 301,223,981 miles (484,773,006 km) at a top speed of 6,200mph (10,000km/h), the spacecraft will have to dramatically decelerate to walking pace and land safely, all within the space of only a few minutes - what scientists call the ‘seven minutes of terror’, from when the probe first enters the thin Martian atmosphere at hypersonic speed to the moment it touches down on the dusty surface of Earth’s planetary neighbour.

Engineers at Nasa’s Jet Propulsion Laboratory in Pasadena, California, are anticipating Insight entering Mars’ atmosphere, then descending with a parachute and retrorockets, finally touching down at approximately 3pm EST (8pm GMT). InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) will be the first mission to study the deep interior of Mars.

“We’ve studied Mars from orbit and from the surface since 1965, learning about its weather, atmosphere, geology and surface chemistry,” said Lori Glaze, acting director of the Planetary Science Division in Nasa’s Science Mission Directorate. “Now we finally will explore inside Mars and deepen our understanding of our terrestrial neighbor as Nasa prepares to send human explorers deeper into the solar system.”

Nasa engineers made a last-minute trajectory correction manoeuvre yesterday to steer InSight within a few kilometres of its targeted entry point over Mars and another may still be necessary. Around two hours before the spacecraft hits the atmosphere, the entry, descent and landing (EDL) team might also upload some final tweaks to the algorithm that guides the spacecraft safely to the surface at Elysium Planitia.

These will be the last commands issued to InSight before it guides itself the rest of the way, as commands sent from Nasa typically take eight minutes to reach the spacecraft 146 million km away. All the engineers can do now is hope everything goes according to plan, with even the Martian weather – dust storms and high winds – throwing up new challenges. The EDL team have been taking the weather reports from Nasa’s Mars Reconnaissance Orbiter into account, as they worked for months to pre-program every stage of InSight’s landing.

Insight's descent (artist's impression)

Insight's descent (artist's impression)

Image credit: Nasa

InSight will transmit messages as it heads down to the surface. These will be relayed back to Earth via two small satellites flying overhead. Radio telescopes at Earth will also be tracking the probe’s progress in case the primary communications link falls over.

Assuming it lands in one piece, InSight is programmed to take a quick snap of its immediate surroundings. This could come back within 30 minutes after safely landing on the surface.

“It’s taken more than a decade to bring InSight from a concept to a spacecraft approaching Mars - and even longer since I was first inspired to try to undertake this kind of mission,” said Bruce Banerdt of JPL, InSight’s principal investigator. “But even after landing, we’ll need to be patient for the science to begin.”

InSight’s mission is the first dedicated to understanding the interior of Mars. Scientists want to know how the planet is constructed, from core to crust. It will provide scientists with another cosmic data reference set with which to compare what is already known about Earth’s make-up and geological history.

“The small details in how planets evolve are what we think make the difference between a place like Earth, where you can go on vacation and get a tan, and a place like Venus where you’ll burn in seconds or a place like Mars where you’ll freeze to death,” said Banerdt.

It will take two to three months for InSight’s robotic arm to set the mission’s instruments on the surface. During that time, engineers will monitor the environment and photograph the terrain in front of the lander, as the surface operations team at JPL will practice setting down the instruments using a working replica of InSight in a special indoor ‘Mars sandbox’, designed to match the actual landing site. The team will check to make sure the instruments can be deployed safely, even if there are rocks nearby or InSight lands at an angle.

InSight has three principal experiments on board. The first is a collection of Franco-British seismometers that will be lifted on to the surface to listen for ‘Marsquakes’. These vibrations will reveal where the rock layers are and what they are made of. Secondly, a German ‘mole’ will burrow 5m down through the surface to take the planet’s temperature, to take readings as to how active Mars is. The third experiment will use radio transmissions to precisely determine to what degree Mars wobbles on its axis, as this is an indication of whether the core is liquid or solid and how big the core is.

Naturally, all of the experiments hinge on a successful landing and the result is far from guaranteed – which is why all eyes at Nasa and JPL will be trained on InSight’s entry and final descent.

“As humanity, as explorers, we’re batting at less than 50 per cent,” said Thomas Zurbuchen, Nasa’s science chief. “Going to Mars is really, really hard.”

mars insight infographic

Image credit: Graphic News

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