More than six months and 300 million miles since it launched from California’s Vandenberg Air Force Base, NASA’s InSight lander is due to arrive at Mars on Monday to study the red planet.

NASA’s study of Mars has focused on the planet’s surface and the possibility of life early in its history. By contrast, the InSight mission — the name is a compression of Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport — will study the mysteries of the planet’s deep interior, aiming to answer geophysical questions about its structure, composition and how it formed.

When is the landing?

The touchdown is predicted to occur at 2:54 p.m. Eastern time.


To be precise, that is the “Earth receive time” — when the signal reporting the landing arrives on Earth (and the start of cheering in the control room).

WATCH LIVE: NASA’s coverage of the landing

The actual landing is scheduled to occur at 2:47 p.m. The radio signal then has to travel 91 million miles to Earth from Mars, arriving some 8 minutes later (the amount of time it takes light to travel this far).

How can I follow the landing?

NASA will broadcast coverage of the landing on the internet beginning at 2 p.m. Eastern time. People in midtown Manhattan can watch it on Nasdaq’s big screen in Times Square.

Sometime after 5 p.m., the space agency will hold a news conference to discuss how everything went.

NASA has also arranged parties around the country — including gatherings at the Los Angeles Central Library, the Adler Planetarium in Chicago and the American Museum of Natural History in New York City — where people can watch the landing with other Mars enthusiasts.

Why is landing on Mars so difficult?

The InSight spacecraft will be traveling at 12,300 mph when it enters the top of Mars’ atmosphere, about 80 miles above the surface. (That is more than 200 miles a minute.) Six and a half minutes later, it will traveling 0 mph, at rest on the ground. That much is certain. (NASA’s spacecraft navigators are really good; they are not going to miss Mars.)


The tricky part is landing in one piece and in working condition. To date, NASA is the only space agency that has accomplished that feat.

A model of the InSight lander is shown at NASA's Jet Propulsion Laboratory on Monday.
A model of the InSight lander is shown at NASA's Jet Propulsion Laboratory on Monday.Marcio Jose Sanchez/associated press

The very thin air of Mars makes landing particularly challenging. There is enough air that the friction of the molecules will heat parts of the outside of InSight to 2,700 degrees Fahrenheit — hot enough to melt steel — but not enough air for the drag to slow the spacecraft much.

Thus, the InSight lander will use a series of mechanisms — a heat shield, parachutes and rocket engines — to slow down. It is to arrive on the Martian surface at a speed of 5 mph. Sixteen minutes later — to allow time for dust kicked up from landing to settle — the spacecraft is to unfurl its solar panels.

NASA engineers know the system can work. The design of InSight is almost identical to that of the Phoenix Mars lander that successfully set down on Mars in 2008.

Where on Mars is InSight landing?

The landing site has the idyllic name Elysium Planitia, near the Equator in the northern hemisphere. Mission scientists have described the region as resembling a parking lot or “Kansas without the corn.”


That is intentional. Because the mission is not interested in rocky terrain or pretty sunsets, planners chose the flattest, safest place that the spacecraft could land.

What do scientists hope to learn?

How often does the ground shake with marsquakes? Just how big is the molten core within Mars? How thick is the crust? How much heat is flowing up from the decay of radioactive elements at the planet’s core? Those are some of questions mission scientists hope to answer.

Journalists gathered at NASA's Jet Propulsion Laboratory awaiting the landing of InSight on Mars.
Journalists gathered at NASA's Jet Propulsion Laboratory awaiting the landing of InSight on Mars.Marcio Jose Sanchez/Associated Press

InSight is carrying two main instruments: a dome-shape package containing seismometers and a heat probe that is to burrow about 16 feet down. NASA has spent $814 million on InSight. In addition, France and Germany invested $180 million to build these main instruments.

The seismometers, which are designed to measure surface movements less than the width of a hydrogen atom, will produce what are essentially sonograms of the planet’s insides. In particular, scientists are looking to record at least 10 to 12 marsquakes over two years. Temblors on Mars are not caused by plate tectonics, like on Earth. Instead they are generated when the planet’s crust cracks because of its interior’s cooling and shrinking. The seismometers could also detect other seismic vibrations from meteors hitting Mars.

With the data, the scientists expect to be able to piece together a three-dimensional picture of the planet’s interior.

When does the main science part of the mission start?

Not for a while.

The first five to six weeks will largely be spent checking the health of the spacecraft, including its robotic arm. After that, the arm will lift the seismometer dome off the main deck of the lander and place it on the ground. The burrowing heat probe will be deployed after that and take about 40 days to reach its final depth of 16 feet.


InSight’s primary mission on the surface is to last nearly two years.

What are those two briefcases flying past Mars on Monday?

Those aren’t briefcases. They’re tiny spacecraft!

NASA is using the InSight mission to test new technology. Two identical spacecraft known as Mars Cube One, or MarCO for short, launched with InSight in May. MarCO A and B then separated from InSight’s cruise stage and have since been trailing behind it.

Hundreds of miniature satellites known as CubeSats have launched into orbit around Earth in recent years, but this is the first time that CubeSats have been sent on an interplanetary voyage.

The MarCO spacecraft will relay InSight telemetry to Earth. If that works, a photograph by InSight could arrive within minutes of its arrival. But NASA is not relying on MarCO. The data will also be relayed through two other orbiting spacecraft, Mars Odyssey and Mars Reconnaissance Orbiter.

What other spacecraft are on and around Mars?

In orbit, NASA also has the Mars Reconnaissance Orbiter, Mars Odyssey and Maven. The European Space Agency has Mars Express and the ExoMars Trace Gas Orbiter. The Indian Space Research Organization has the Mars Orbiter Mission, also known as Mangalyaan.


On the surface, NASA currently has the Curiosity and Opportunity rovers, although solar-powered Opportunity has been quiet since the summer when a global dust storm prevented it from generating enough power to operate. NASA is hoping that Opportunity will revive now the skies have cleared.

What missions to Mars are planned for the future?

The year 2020 could be busy.

NASA is planning to launch another rover, similar to Curiosity but with a different set of instruments that will search for the building blocks of life. A collaboration between the European Space Agency and Russia will launch the ExoMars, which will also carry instruments to try to answer whether life could have ever existed on Mars.

China, Japan, the United Arab Emirates and India also intend to launch spacecraft to Mars in 2020.