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Space

Nasa’s new Mars spacecraft lands Monday – if it survives perilous ‘six-and-a-half minutes of terror’

  • The lander is the first to reach Mars since 2012, when Nasa’s Curiosity rover touched down to scour the surface
  • Of 43 other international attempts to send orbiters, probes, landers or rovers to Mars, 25 have not made it
PUBLISHED : Sunday, 25 November, 2018, 10:24am
UPDATED : Sunday, 25 November, 2018, 9:19pm

A spacecraft that cost nearly a billion dollars is on course to make a perilous landing Monday on Mars, if it can survive a high-speed approach and the scorching heat of entering the Red Planet’s atmosphere, a process Nasa has nicknamed “six-and-a-half minutes of terror”.

“There is very little room for things to go wrong,” said Rob Grover, head of the entry, descent and landing team at Nasa’s Jet Propulsion Laboratory in Pasadena, California.

If successful, the entry, descent and landing of the Mars InSight – designed to be the first mission to listen to the interior of another planet and reveal how rocky planets formed – will add another success to Nasa’s record when it comes to sending spacecraft to Mars.

So far the United States is the only nation to have made it there, and only Nasa’s unmanned Curiosity robotic rover is still tooling around on the surface. The space agency’s older, smaller Opportunity was roaming around up there until June, when a global dust storm knocked it out of service.

But if InSight fails, it certainly won’t be the first.

Of 43 other international attempts to send orbiters, probes, landers or rovers to Mars, 25 have not made it.

Either they crashed into the surface, missed their planned orbit, or disappeared after launch.

There will not be any live video streaming of Mars InSight’s approach on Monday, and signals will be transmitted back to Earth on an eight-minute delay.

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Nor can mission managers intervene if anything goes awry. The entire landing sequence is all preprogrammed into the on-board flight computer.

“Going to Mars is really, really hard,” Nasa’s top science mission official, Thomas Zurbuchen, said last week.

“As humanity, the explorers all over the world, we’re batting about 50 per cent – or less.”

Humanity’s nearly 60-year history of trying to get to Mars includes attempts to fly past the red planet for picture-taking without stopping, as well as the vastly more complicated efforts to put spacecraft into orbit around the red planet and to actually land.

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Nasa’s Mariner 4 performed the first successfully fly-by of the red planet in 1965, sending back 21 photos.

Mariner 9 made it into orbit around Mars and beamed back more than 7,000 photos.

And Nasa’s Vikings 1 and 2 not only put spacecraft into orbit around Mars in 1976, but on the surface, too. The twin Vikings were the first successful landers on Mars from planet Earth.

The 1990s weren’t as kind for Nasa. A humiliating English-metric conversion screw-up doomed the Mars Observer in 1993.

Another US orbiter later was lost, as well as a lander and two accompanying probes meant to penetrate the surface.

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Despite decades of trying, Russia, in particular, has had lousy luck at Mars.

The then Soviet Union was the first to attempt a fly-by of Mars, in 1960. The spacecraft never reached Earth orbit.

After more launch failures and flight mishaps, the Soviets finally got a pair of spacecraft into Mars orbit in 1971 and got back real data. But the companion landers were a total bust.

And so it’s gone for the Soviets/Russians through their most recent attempt with China in 2011. The daunting goal was to land a spacecraft on Mars’ moon Phobos to collect and return samples, and to put a second spacecraft into orbit around Mars. Neither made it out of Earth orbit.

Europe also has been snakebitten at Mars, as has Japan.

While the European Space Agency has satellites working around Mars, both of its landing attempts have flopped. Just two years ago, its lander hit the surface so fast, it dug out a crater. Japan’s sole Mars spacecraft, launched in 1998, didn’t make it into orbit.

India, meanwhile, has been operating a satellite around Mars for four years, its first and only shot at the red planet.

There’s a heavy European presence on Nasa’s InSight. Germany is in charge of the mechanical mole that’s designed to burrow 5 metres (16 feet) into the Martian surface to take underground heat measurements, while France directs the lander’s quake-monitoring seismometer.

On the surface, Curiosity is the only thing operating on Mars. Currently in orbit: US Odyssey since 2001, Europe’s Mars Express (2003), US Mars Reconnaissance Orbiter (2006), US Maven (2014), India’s Mangalyaan orbiter (2014) and Europe’s Trace Gas Orbiter (2016).

A brief rundown of InSight’s do-or-die landing

Six minutes before touchdown

InSight will come in like a 19,800km/h (12,300mph) arrow, piercing the top of the Martian atmosphere about 114km (77 miles) above the surface. Engineers are shooting for a 12-degree angle of attack, almost parallel to the ground. Too steep, the spacecraft could burn up. Too shallow, it could bounce back into space. Atmospheric friction slows the spacecraft, but builds up heat. Its heat shield is made to withstand the 1,500 degrees Celsius (2,700 Fahrenheit). Once InSight is down to 11km its parachute opens at a breakneck 1,400km/h.

Three minutes

Shortly after the white nylon chute opens with a yank, InSight ditches its heat shield and unfolds its three legs. After two minutes of descending under the parachute, the spacecraft, still supersonic, starts using radar to determine speed and altitude, from 2½ km up.

45 seconds

Almost immediately, InSight’s 12 descent engines start firing to further slow the lander and keep it away from the severed back shell, still falling under the parachute. The lander turns itself so its solar panels will extend east and west at touchdown, and its robotic arm faces south. InSight’s speed is now 27km/h, at an altitude of 50 meters (164 feet).



15 seconds

Now in so-called constant velocity mode, InSight is aiming for a 8km/h touchdown in a plain near the equator called Elysium Planitia.



Touchdown

It will be around 2pm, Mars time, when InSight lands. That’s 3pm on the US East Coast and 4am Hong Kong time (Tuesday). Nasa estimates temperatures could be well below zero Celsius.

Hello, hello?

Since departing Earth in May, InSight has been shadowed by WALL-E and EVE, the first CubeSats to venture into deep space. The briefcase-size satellites named after the characters in the 2008 animated movie will pass within a few thousand kilometres of Mars, as InSight lands. Nasa hopes one or both relay InSight’s radio signals. .

Say cheese

InSight’s first job, just several minutes after landing, is to take a picture. Ground controllers want to see what they’re up against. Once the red dust settles about 16 minutes after touchdown, the lander will spread its solar panels and settle in for its first long winter’s nap at Mars.

Agence France-Presse, Associated Press