May 5, 2018

— The first spacecraft dedicated to studying the deep interior of Mars is now bound for the Red Planet.

NASA's InSight Mars lander, which will try to detect marsquakes and monitor the flow of heat below the Martian surface for the first time, lifted off on Saturday (May 5) from Space Launch Complex-3 at Vandenberg Air Force Base in California. The 4:05 a.m. PDT (7:05 a.m. EDT or 1105 GMT) liftoff made history as the first launch of a NASA interplanetary mission from the U.S. west coast.

Not that spectators in the immediate vicinity could catch sight of that history being made.

A thick layer of fog blanketed the launch site, leaving only the thunderous sound of the United Launch Alliance (ULA) Atlas V 401 rocket as evidence that the InSight mission was underway.

Despite the lack of visibility, the launch went without issue, with InSight separating from the Atlas V's Centaur upper stage 93 minutes after it left the ground.

The successful ascent began InSight (short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) on its trajectory to touch down on the lava plains of Mars' Elysium Planitia around noon PST (3 p.m. EST or 2000 GMT) on Nov. 26.

The short and long of it

The four-legged InSight lander, stowed inside a heat shield-capped aeroshell and topped with a cruise stage, will take 205 days to travel the approximate 301 million miles (485 million kilometers) from Earth to Mars.

InSight mission to Mars launch. Click to enlarge and view in a new window. (NASA/JPL)

Launched alongside and now trailing InSight are two small satellites — nicknamed "Wall-E" and "Eve" after the Disney Pixar animated robots — that are designed to test deep-space communications and relay data from InSight as it begins its entry into Mars' atmosphere. The Mars Cube One, or MarCO, duo are the first cubesats launched to another planet.

InSight, using a similar approach to NASA's Phoenix Mars lander, will plunge into the Martian atmosphere at a higher velocity and with more mass than the previous 2008 mission. InSight will also land at a higher elevation (about 4,900 feet or 1500 meters) than Phoenix, and arrive at the time on Mars when dust storms have been known to grow to global proportions in some prior years.

As such, InSight's heat shield was made thicker to handle the possibility of being sandblasted by a dust storm and its parachute, suspended from stronger lines, will open at a higher speed.

In the final moments of its planned descent, InSight will separate from its aeroshell and ignite its thrusters to land.

Once down, it will still be several weeks more before InSight's science mission can begin.

Within its first half hour on Mars, the lander will unfurl its two circular solar arrays to power its instruments. It will then use a robotic arm to position its seismometer and heat flow probe on the surface.

"It's essentially a second entry, descent and landing for us," said Tom Hoffman, the project manager for the InSight mission at the Jet Propulsion Laboratory (JPL) in Pasadena, California. "We are only about a meter, or three feet, from the [lander's deck to the] ground, but we've got to get that last little bit and that is actually going to take us a little bit of time."

Using photos of the landing site taken by InSight's cameras, mission planners will reproduce that terrain in a test bed at JPL and then practice deploying each of the instruments multiple times to make sure the lander on Mars gets it exactly right.

"That's going to take us about two months," said Hoffman. "I wish it was about five minutes."

Pulse of a planet

Planned as a two year (or one Martian year plus 40 Martian day, or sol) mission, InSight's science instruments were developed to take the "vital signs" of Mars — its pulse (seismology), its temperature (heat flow) and its reflexes (radio science) — to give scientists a look at how rocky planets like Earth and Mars evolved.

"The science we want to do with this mission, the reason we are going to Mars, is really the science of understanding the early solar system and how rocky planets form," said Bruce Banerdt, InSight's principal investigator at JPL.

For the first time since NASA's Viking missions, a seismometer will take readings on Mars, and unlike the late-1970s landers, InSight's measurements will be taken on the surface (as opposed to the Vikings, which had their seismometers mounted atop the spacecraft).

The Seismic Experiment for Interior Structure (SEIS), which was provided to the mission by a consortium led by France's national space agency, Centre National d'Études Spatiales (CNES), will precisely measure the ground motions in a range of frequencies.

"This is really the heart of the mission," explained Banerdt. "The seismometer is what allows us to see deep into the planet, to have insight into the planet. It uses the seismic waves generated by marsquakes."

Scientists expect between a dozen and one hundred marsquakes over the course of InSight's two (Earth) year mission. The quakes are likely to be no bigger than a 6.0 on the Richter scale, but will be of enough energy to reveal details about the planet's interior.

"Our second instrument is the Heat Flow and Physical Properties Probe. This the mole that goes down into the Martian soil about 5 meters, or about 16 feet, and it measures not just the temperature down there, but the temperature all along the hole that it went down," said Banerdt.

Provided by the German Aerospace Center DLR, HP3 (pronounced "H-P cubed") will take about seven weeks to burrow 15 times deeper beneath the surface than any previous Mars hardware. It will provide the first precise determination of the amount of heat escaping from the planet's interior.

InSight's third science experiment, the Rotation and Interior Structure Experiment (RISE), does not have its own dedicated instrument. Instead, it uses the lander's direct radio connection with Earth to assess perturbations of Mars' rotational axis, which can provide information about the planet's core.

"By analyzing the doppler shift and timing of the signal, we can track the location of the spacecraft at Mars, I don't know 60 million, 100 million miles away, with an accuracy of something around a foot or so," described Banerdt. "To me, that is as close as you can get to magic and still be science."

Legacy and heritage

Part of NASA's Discovery Program of competitively selected missions for exploring the solar system, InSight uses many of the design aspects of the stationary-lander mission already proven by NASA's Phoenix Mars lander. But its connection to past missions doesn't end there.

"One of our strategies was to build upon our previous successes," said Stu Spath, InSight program manager for Lockheed Martin Space Systems, which assembled the spacecraft for NASA.

"The avionics, the power components and flight computer, those are all inherited from MAVEN, the Mars orbiter launched in 2013," he said. "So we've modernized the electronics since the Phoenix era."

InSight's almost 8-foot-long (2.4-m) instrument deployment arm was reused from NASA's cancelled 2001 Surveyor lander. The lander's two color cameras are flight spares from the 2012 Mars Science Laboratory Curiosity rover, which in turn were copies of the cameras on the Mars Exploration Rovers, Spirit and Opportunity.

InSight's hardware heritage was not limited to past Mars missions, either.

"And we have a small deep space transponder on the cruise stage which is legacy back to Juno," said Hoffman, referring to the spacecraft circling Jupiter since July 2016.

In addition to legacy and heritage hardware, the InSight lander also carries a pair of silicon chips that were etched with names of approximately 2.4 million people worldwide who participated in an online "send your name to Mars" campaign. The chips are mounted near the northern edge of InSight's deck.