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Mars InSight
An artist’s impression shows the Mars InSight lander and a cutaway view of Mars’ subsurface, with the lander’s heat probe deployed underground. (NASA Illustration)

NASA’s Mars InSight lander is being prepped for a launch that will send some magical science and engineering toward the Red Planet, including two pint-sized piggyback probes and a seismometer that can measure distances less than the width of an atom.

Now, if only NASA could work its magic on the weather for Saturday’s scheduled 4:05 a.m. PT liftoff from California’s Vandenberg Air Force Base.

“There is an 80 percent chance you will not be able to see the rocket launch at liftoff. … We are anticipating visibility to be bad that day,” Air Force 1st Lt. Kristina Williams, weather officer for the 30th Space Wing, said today at a pre-launch briefing.

The launch pad is expected to be socked in with fog for NASA’s first-ever interplanetary launch from the U.S. West Coast. But that fog won’t necessarily hold up liftoff for the United Launch Alliance Atlas 5 rocket that’s primed to send Mars InSight spaceward.

NASA and ULA “are prepared to launch through it” if everything else is go for launch, Williams said. And a day and a half before launch, everything else is indeed go.

After a murky start, it should be clear sailing for the nearly $1 billion U.S.-European mission, which will measure Mars’ seismic activity and interior temperature shifts. The mission’s name is an acronym of sorts, standing for “Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport.”

Mars InSight’s car-sized spacecraft was built on the same basic platform that was used for the Phoenix Mars Lander a decade earlier, with a totally new set of instruments and electronics. It’s due to touch down on Elysium Planitia, a plain near the Martian equator, on Nov. 26 after a six-month, 300 million-mile cruise.

Sensitive seismometer

The spacecraft’s main instrument is a seismometer that’s designed to detect the deep rumblings of the Red Planet, due to “Marsquakes” as well as meteorite strikes. Data sent back to Earth will help scientists figure out Mars’ internal structure.

The seismometer is sensitive enough to measure movements amounting to half the radius of a hydrogen atom, according to the mission’s principal investigator, Bruce Banerdt of NASA’s Jet Propulsion Laboratory.

It’s so sensitive, in fact, that the quake-detecting apparatus has to be enclosed in a vacuum chamber and shielded from the wind and from Mars’ temperature swings.

Getting this part of the mission right held back Mars InSight’s launch by more than two years. When the French-built equipment was tested back in 2015, engineers found a slight leak in the vacuum chamber. The leak couldn’t be fixed in time for the original launch date in 2016, so NASA had to wait another 26 months for the planets to align again.

Measuring Mars

After Mars InSight’s robotic arm deploys the seismometer, it will stretch out again to deploy a heat probe, officially known as Heat Flow and Physical Properties Probe or HP3, but nicknamed the “mole.” The mole will hammer its way through Martian soil, to a depth of as much as 16 feet.

Temperature sensors attached to the mole will take readings at various depths, revealing precisely how much heat is escaping from Mars’ interior. That should give scientists a better idea about what Mars is made of, down deep.

Mars InSight’s radio antennas will be used for science as well: They’ll receive transmissions from Earth and sent them back in such a way that the signals’ subtle Doppler shift can be measured precisely. Scientists should be able to measure changes in distances amounting to as little as a foot, across a span of tens of millions of miles.

“To me, that’s as close as you can get to magic and still be science,” Banerdt said. He said measurements of the Red Planet’s wobble on its axis will help scientists determine the size of its core, its density and its composition.

Mars InSight should shed new light on the origins of the solar system, in part because Mars retains more of its long-ago geological history than our active Earth does.

“We call it the Goldilocks planet: It’s not too big, it’s not too small, it’s just right. … We have lots of geology going on at the surface, but all of those fingerprints of [ancient] processes are still retained in the deep interior,” Banerdt said.

NASA chief scientist Jim Green said learning about Marsquakes will also help the space agency get ready to send astronauts to the Red Planet and build habitats there. “How quake-prone is Mars? That’s fundamental information that we need to know as humans explore Mars,” Green said.

Rocket ride-share

The Mars InSight lander isn’t the only spacecraft packed aboard the mission’s Atlas 5 rocket: Two CubeSat probes, each about the size of a jumbo cereal box, will test technologies that could be used for future miniaturized space missions. They’re due to be deployed about an hour and a half after launch and follow parallel paths to their own Mars flybys.

“It is really a collaboration of the entire CubeSat community, building upon all the effort that has been done over the last 20 years, that allows us to take the first CubeSats out to deep space,” said JPL’s Andy Klesh, chief engineer for the MarCO piggyback missions.

The CubeSats will test a propulsion system that uses compressed gas, much like the stuff that’s bottled up in fire extinguishers. The probes are officially known as MarCO-A and MarCO-B — but they’ve been nicknamed WALL-E and EVE, after the stars of the animated film “WALL-E,” because fire-extinguisher propellant played a crucial role in getting those robots out of a space jam.

WALL-E and EVE will also test a new type of flat, foldable radio antenna that’s designed to provide as much capability as a traditional parabolic dish. The system will be used to relay signals from the Mars InSight lander as it makes its descent to the Martian surface.

There’s one more tiny payload hitching a ride to Mars: a pair of silicon microchips that bear the etchings of more than 2.4 million names. The names were sent in as part of a public outreach campaign.

Atlas Mars InSight launch visibility
This map shows areas where the ascent of Mars InSight’s Atlas 5 rocket could be visible. (ULA Graphic)

Looking for launch

NASA is scheduled to start webcast coverage of Saturday’s Mars InSight countdown at 3:30 a.m. PT. If the launch has to be scrubbed, due to weather or technical issues, NASA can try, try again until June 8, when this year’s window closes. After June, the next opportunity doesn’t come around until 2020.

Scott Messer, United Launch Alliance’s program manager for NASA missions, said Vandenberg was chosen for the Mars InSight launch because the schedule for liftoffs from Florida was looking “a little crowded,” and because the payload was light enough to take advantage of California’s circumstances.

Vandenberg is best suited for launches into a pole-to-pole orbit, which is fine for Earth-orbiting satellites but typically not as good for interplanetary missions. For Mars InSight, mission planners mapped out an unusual route to deep space.

“We’re going to end up doing one orbit, like a polar orbit, and then we’re going to make a left turn on our way to Mars,” said JPL’s Tom Hoffman, who’s the project manager for Mars InSight.

Because the Atlas 5 pushes the probe southward from Vandenberg, the rocket’s ascent should be visible along a stretch of the California coast extending from north of San Luis Obispo to south of San Diego.

That is, assuming you’re not stuck in the fog.

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