Whenever scientists and engineers at NASA’s Jet Propulsion Laboratory prepare for one of their spacecraft to touch down on the surface of Mars, the mood is reminiscent of a big family gathering. The only difference is that no one knows until it’s over if they’ve come together for a wedding or a funeral.
Around 3 p.m. Eastern Time on Monday, the team behind the Mars InSight mission will find out if their US$1-billion probe is sitting safely at its landing site on Elysium Planitia – a smooth rock-strewn plateau whose name roughly translates as “heavenly plain” – or whether it is a smoking heap of space junk. To survive its seven-minute plunge through the thin Martian atmosphere, the probe will have to decelerate from a cruising speed of about 20,000 kilometres an hour to a mere eight km/h when it contacts the surface.
A one-off mission, InSight is a departure from NASA’s long-term strategy of collecting and retrieving samples from the Martian surface. As its name implies, it is the first probe sent to Mars with the specific task of exploring the planet’s deep interior, an effort that is unlikely to be repeated for many years if something goes wrong.
ROCKY PLANETS - THE INSIDE STORY
Earth is the largest rocky planet in our solar system with an internal structure that includes a rock mantle and metallic core. Seismic data from the InSight mission will help determine if the Martian core is partly liquid and help clarify how the planet’s internal geology may have influenced prospects for life on the surface eons ago.
400 km
Continental crust
30 - 50 km
670 km
Upper
mantle
2,090 km
Lower
mantle
Fluid
outer
core
5,150 km
Solid
inner
core
EARTH
6,370 km
1,150 km?
Mantle
Ballistic crust
30 - 60 km?
1,670 km?
Solid or
liquid
core?
MARS
3,390 km?
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA
ROCKY PLANETS - THE INSIDE STORY
Earth is the largest rocky planet in our solar system with an internal structure that includes a rock mantle and metallic core. Seismic data from the InSight mission will help determine if the Martian core is partly liquid and help clarify how the planet’s internal geology may have influenced prospects for life on the surface eons ago.
400 km
Continental crust
30 - 50 km
670 km
Upper
mantle
2,090 km
Lower
mantle
Fluid
outer
core
5,150 km
Solid
inner
core
EARTH
6,370 km
1,150 km?
Mantle
Ballistic crust
30 - 60 km?
1,670 km?
Solid or
liquid
core?
MARS
3,390 km?
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA
ROCKY PLANETS - THE INSIDE STORY
Earth is the largest rocky planet in our solar system with an internal structure that includes a rock mantle
and metallic core. Seismic data from the InSight
mission will help determine if the Martian core
is partly liquid and help clarify how the planet’s
internal geology may have influenced prospects
for life on the surface eons ago.
400 km
Continental crust
30 - 50 km
670 km
Upper
mantle
2,090 km
Lower
mantle
Fluid
outer
core
5,150 km
Solid
inner
core
EARTH
6,370 km
1,150 km?
Ballistic crust
30 - 60 km?
1,670 km?
Mantle
Solid or
liquid
core?
MARS
3,390 km?
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA
That raises the stakes for the scientists who have long pushed for InSight.
“I have to admit, I’m getting a little nervous,” said Bruce Banerdt, the mission’s principal investigator.
The European Space Agency has partnered with NASA on InSight and some Canadian researchers are also participating.
It’s been almost exactly 19 years since NASA last failed to get a probe down onto the Martian surface. The loss of the Mars Polar Lander on Dec. 3, 1999, led to a complete overhaul of NASA testing and management of subsequent projects. Since then, four missions have touched down safely, including the Curiosity rover in August, 2012.
Standing about one metre tall when fully deployed, InSight is less than half the height and mass of the car-size Curiosity. It is also built to stay in one place and deploy a suite of sensors that will probe the world far beneath its metal feet, including a sensitive seismometer that will listen for “marsquakes” rattling the Martian bedrock.
Dr. Banerdt compared the quakes to camera flashbulbs, because their vibrations can be used to momentarily reveal hidden structures in the planet’s interior, including the thickness and makeup of its crust, mantle and core.
That information, in turn, will allow scientists to reconstruct how Mars formed and evolved over geologic time, shedding light on Earth’s own ancient trajectory as a relatively larger and more habitable world.
A geophysicist by training, Dr. Banerdt was already a student working here when the laboratory’s Viking 1 and Viking 2 probes became the first to successfully land on Mars in 1976. While Viking was celebrated as a major milestone for space exploration, a lingering disappointment with its seismic experiments helped guide the design of InSight decades later, he said.
Both Viking probes carried a seismometer, but the instrument on Viking 1 failed. On Viking 2, vibrations from the spacecraft overwhelmed the data with noise, which meant scientists could draw no conclusions from their measurements.
“The lesson from Viking was never bring a seismometer to Mars unless you’re serious about putting it on the ground,” he said.
InSight will do exactly that. At a pace that Dr. Banerdt said will be like a “mission in slow motion,” the spacecraft is meant to inspect its landing site over a two- to three-month period before it is finally ready to use its robot arm to gently place a seismometer on the rust-coloured surface. It will also place a dome-shaped wind and thermal shield over the instrument to improve its sensitivity.
Also key to the experiment is the magnetometer that resides on the probe’s instrument deck. Because InSight’s seismometer can be affected by changes in the magnetic environment due to the solar wind, the magnetic readings are needed to calibrate the seismic data.
The magnetometer will also be able to provide some useful data on its own and in tandem with the Maven spacecraft that has been in orbit around Mars since 2014, said Catherine Johnson, a University of British Columbia professor who is leading InSight’s magnetometer science.
“We’re really excited because there are things we’re hoping to do in terms of joint observations,” Dr. Johnson said, including looking at the Martian ionosphere, a region of electrically charged particles that surround the planet.
If all goes as planned, then the magnetometer will be switched on as early as Thursday, she said.
That, of course, remains a big if.
“We’ve done everything we can. We’ve done everything we can think of,” project manager Tom Hoffman said during the Sunday briefing. “But Mars could always throw us a curveball.”
ENTRY, DESCENT AND LANDING
The most harrowing moments for the mission will occur during the approximately seven minutes that it takes to go from a high-speed space cruise to a safe deployment on the surface. The 360-kilogram lander will be
protected by a heat shield during the first part of its descent, after which it will be slowed
by a parachute and then, for the final
40 seconds, by firing engines.
ENTRY
PREP
PHASE
Final perameter
updates and entry
state initialization
Cruise stage
speration and entry
turn starts
Entry, peak heating
and deceleration
then parachute
deployment
HYPERSONIC
PHASE
PARACHUTE
PHASE
Heat shield jettison
Leg deployments,
radar activated
Lander separation,
gravity turn start,
engines fire
TERMINAL
DESCENT
PHASE
Touchdown
MARS
SURFACE
Solar array
deployment,
gyro-compassing
begins
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA
ENTRY, DESCENT AND LANDING
The most harrowing moments for the mission will occur during the approximately seven minutes that it takes to go from a high-speed space cruise to a safe deployment on the surface. The 360-kilogram lander will be protected by a heat shield during the first part of its descent,
after which it will be slowed by a parachute and then,
for the final 40 seconds, by firing engines.
ENTRY
PREP
PHASE
Final perameter
updates and entry
state initialization
Cruise stage
speration and entry
turn starts
Entry, peak heating
and deceleration
then parachute
deployment
HYPERSONIC
PHASE
PARACHUTE
PHASE
Heat shield jettison
Leg deployments,
radar activated
Lander separation,
gravity turn start,
engines fire
TERMINAL
DESCENT
PHASE
Touchdown
MARS
SURFACE
Solar array
deployment,
gyro-compassing
begins
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA
ENTRY, DESCENT AND LANDING
The most harrowing moments for the mission will occur during the approximately seven minutes that
it takes to go from a high-speed space cruise to a safe deployment on the surface. The 360-kilogram lander will be protected by a heat shield during the first part of its descent, after which it will be slowed
by a parachute and then, for the final 40 seconds,
by firing engines.
ENTRY
PREP
PHASE
Final perameter
updates and entry
state initialization
Cruise stage
speration and entry
turn starts
HYPERSONIC
PHASE
Entry, peak heating
and deceleration
then parachute
deployment
PARACHUTE
PHASE
Heat shield jettison
Leg deployments,
radar activated
Lander separation,
gravity turn start,
engines fire
TERMINAL
DESCENT
PHASE
Touchdown
MARS
SURFACE
Solar array
deployment,
gyro-compassing
begins
TRISH McALASTER / THE GLOBE AND MAIL
SOURCE AND PHOTO: NASA