Posted on by Elizabeth Howell

NASA Mars Lander InSight ‘Go’ For Construction

Artist's conception of the NASA InSight Mars lander. Credit: NASA/JPL-Caltech

It’s time to get ready for Mars, again! NASA has given the approval to begin construction on its 2016 mission, the Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) mission.

As the mission implies, the lander (which isn’t moveable) will focus on learning more about the inside of Mars. The idea is to figure out how terrestrial planets are “differentiated” inside between core, mantle and crust. Also, watchers of the Mars program may recognize some parts of the lander, as it will borrow the design from the successful Phoenix mission in 2008.

“We will incorporate many features from our Phoenix spacecraft into InSight, but the differences between the missions require some differences in the InSight spacecraft,” stated Stu Spath, InSight program manager at Lockheed Martin.

“For example, the InSight mission duration is 630 days longer than Phoenix, which means the lander will have to endure a wider range of environmental conditions on the surface.”

View of Mars' surface near the north pole from the Phoenix lander. Credit: NASA/JPL-Calech/University of Arizona
View of Mars’ surface near the north pole from the Phoenix lander. Credit: NASA/JPL-Calech/University of Arizona

NASA mission planners are still determining where InSight will go, but they expect it will be a site near the equator of Mars and that it will last at least two years on the surface.

The Mars lander will include a robotic arm with “surface and burrowing” instruments whose projects are led by the French and German space agencies, which are CNES (National Center of Space Studies) and DLR (German Center for Aerospace), respectively. CNES will contribute a seismic experiment to look at “Marsquakes” and when meteors smack the surface, while DLR’s science experiment will look at interior planetary heat.

Mars on March 8, 2014 shows not only clouds over Hellas but evening limb clouds. Credit: W.L. Chin
Mars on March 8, 2014 shows not only clouds over Hellas but evening limb clouds. Credit: W.L. Chin

The seismometer will sit on the surface, covered up to protect it from the cold and wind, while the heat-flow probe will be hammered in about three to five yards or meters. Investigators also plan an experiment that will communicate with NASA’s Deep Space Network antenna network to see how much the rotation of Mars wobbles, which could hint if the core of the Red Planet is solid or liquid. The mission will also include wind, temperature and pressure sensors, as well as a magnetometer.

“Mars actually offers an advantage over Earth itself for understanding how habitable planetary surfaces can form,” stated Bruce Banerdt, InSight principal investigator at NASA’s Jet Propulsion Laboratory. “Both planets underwent the same early processes. But Mars, being smaller, cooled faster and became less active while Earth kept churning. So Mars better preserves the evidence about the early stages of rocky planets’ development.”

Construction will be led by Lockheed Martin. You can check out more information about InSight at this website. NASA has several missions working at Mars right now, such as the Mars Curiosity rover, the Opportunity rover and the orbiting Mars Reconnaissance Orbiter and Mars Odyssey spacecraft.

Source: Jet Propulsion Laboratory

Posted on by Michael Habib

Let’s Put a Sailboat on Titan

An illustration showing how a sailboat mission to Titan might land and become operational. Copyright: Estevan Guzman for Universe Today.

The large moons orbiting the gas giants in our solar system have been getting increasing attention in recent years. Titan, Saturn’s largest moon, is the only natural satellite known to house a thick atmosphere. It’s surface, revealed in part by the Cassini probe, is sculpted by lakes and rivers. There is interest in exploring Titan further, but this is tricky from orbit because seeing through the thick atmosphere is difficult. Flying on Titan has been discussed around the web (sometimes glibly), and this was even one of the subjects treated by the immensely popular comic, XKCD.

However, there remains the problem of powering propulsion. The power requirements for flight are quite minimal on Titan, so solar wings might work. But Titan also presents an alternative: sailing.

Images from the Cassini mission show river networks draining into lakes in Titans north polar region. Credit: NASA/JPL/USGS.
Images from the Cassini mission show river networks draining into lakes in Titans north polar region. Credit: NASA/JPL/USGS.

With all those lakes and rivers, exploring Titan with a surface ship might be a great way to see much of the moon. The vehicle wouldn’t be sailing on water, though. The lakes on Titan are composed of liquid methane. The challenge is therefore making the vessel buoyant: liquid methane is only 45% as dense as liquid water. This means we would need a lot of displacement. A deep, hollow hull could do this, however, and it turns out that the liquid methane has an advantage that helps make up for the low density: it is much less viscous than water.

Reynolds number is proportional to the ratio of density to viscosity, and it turns out that friction drag on a hull is inversely proportional to Re. While Titan’s seas and lakes have only 45% the density of water, they also have only 8% of the viscosity. This means that the Titan sailing vessel would only experience about 26% of the friction drag as its Earth equivalent. [Yacht designers have found that the friction drag is about equal to 0.075/(log(Re)-2)^2)]. That leaves us room to make the hull deeper (important to compensate for the density as above), and longer (if we want a longer waterline, which will make the bow waves longer and improve maximum speed).

The sail itself would get less wind, on average, on Titan than Earth. Average wind speeds on Titan seem to be about 3 meters/s, according to Cassini, though it might be higher over the lakes. Average wind speed over Earth oceans is closer to 6.6 meters/s. But, the Titan atmosphere is also about 4x denser than Earth’s, and both lift and drag are proportional to fluid density. All told, this means that the total fluid force on the sail will be about 83% of what you’d get on Earth, all else being equal, which could be sufficient. There would be a premium on sail efficiency and size, and so we might have to take advantage of the low-friction hull to examine shapes with more stability that can house a larger, taller (and presumably high aspect ratio) sail.

This is all quite speculative, of course, but it provides a fun exercise and perhaps provides inspiration as we imagine tall-sailed robotic vessels silently cruising the lakes of Titan.

Titan Mare Explorer. Image credit: NASA/JPL
Titan Mare Explorer. Image credit: NASA/JPL

One concept for a boat on Titan has already been proposed: the Titan Mare Explorer (TiME) would send a floating high-tech buoy to land in a methane sea on this moon of Saturn to study its composition and its interaction with the atmosphere. But this Discovery-class mission concept was nixed in favor of sending the InSight lander to Mars.

But with all the recent discoveries on Titan by the Cassini spacecraft — things like lakes, seas, rivers and weather and climate patterns that create both fog and rain — a mission like this will be given more consideration in the future.

Posted on by Nancy Atkinson

Where’s the Best Place To Drill for History on Mars?

The process of selecting a site for NASA's next landing on Mars, planned for September 2016, has narrowed to four semifinalist sites located close together in the Elysium Planitia region of Mars. The mission known by the acronym InSight will study the Red Planet's interior, rather than surface features, to advance understanding of the processes that formed and shaped the rocky planets of the inner solar system, including Earth. Image credit: NASA/JPL-Caltech

Where’s the best place to drill baby, drill on Mars – and not for oil but digging into Mars’ past? Apparently, a relatively level spot near the equator is the preferred spot. The 2016 InSight lander is the next mission to land on Mars and it will use a probe to hammer down 3-5 meters under the surface. NASA has now narrowed down the potential landing sites to just four from an original twenty-two proposed locations, and all four lie along the planet’s mid-section on the plains of Elysium Planitia.

“We picked four sites that look safest,” said geologist Matt Golombek from the Jet Propulsion Laboratory. Golombek is leading the site-selection process for InSight. “They have mostly smooth terrain, few rocks and very little slope.”

This artist's concept depicts the stationary NASA Mars lander known by the acronym InSight at work studying the interior of Mars. Image credit: JPL/NASA
This artist’s concept depicts the stationary NASA Mars lander known by the acronym InSight at work studying the interior of Mars. Image credit: JPL/NASA

InSight stands for “Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport” and it is scheduled to launch in March 2016 and land in September of that year. The mission will investigate processes that formed and shaped Mars and will help scientists better understand the evolution of our inner solar system’s rocky planets, including Earth. It will also monitor the planet’s current internal temperature and any seismology taking place.

So, unlike previous Mars landings, what is on the surface in the area matters little in the choice of a site except for safety considerations.

“This mission’s science goals are not related to any specific location on Mars because we’re studying the planet as a whole, down to its core,” said Bruce Banerdt, InSight principal investigator. “Mission safety and survival are what drive our criteria for a landing site.”

Elysium works well for the InSight mission because of two basic engineering constraints. One requirement is being close enough to the equator for the lander’s solar array to have adequate power at all times of the year. Also, the elevation must be low enough to have sufficient atmosphere above the site for a safe landing. The spacecraft will use the atmosphere for deceleration during descent.

InSight also needs penetrable ground for its probe that will monitor heat coming from the planet’s interior. This tool can penetrate through broken-up surface material or soil, but could be foiled by solid bedrock or large rocks. InSight also will deploy a seismometer on the surface and will use its radio for scientific measurements.

Images from the Mars Reconnaissance orbiter have been crucial in narrowing down the sites, and will continue to aid scientists and engineers in choosing the final site.

Golombek said that since considering what is below the surface is important to evaluate candidate landing sites, scientists also studied MRO images of large rocks near Martian craters formed by asteroid impacts. Impacts excavate rocks from the subsurface, so by looking in the area surrounding craters, the scientists could tell if the subsurface would have probe-blocking rocks lurking beneath the soil surface.

Each semifinalist site is an ellipse measuring 81 miles (130 kilometers) from east to west and 17 miles (27 kilometers) from north to south. Engineers calculate the spacecraft will have a 99-percent chance of landing within that ellipse, if targeted for the center.
The team will select two or three finalists by the end of 2014, and make a final decision on InSight’s destination by the end of 2015.

Posted on by Nancy Atkinson

Mars Lander Wins Out for 2016 Mission Over Titan Boat and Comet Hopper

Artist rendition of NASA’s Mars InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) Lander. InSight is based on the proven Phoenix Mars spacecraft and lander design with state-of-the-art avionics from the Mars Reconnaissance Orbiter (MRO) and Gravity Recovery and Interior Laboratory (GRAIL) missions. Credit: JPL/NASA

A new mission to Mars will launch in 2016, NASA announced on Monday, a lander named InSight that will probe Mars’ interior to determine whether it has a solid or liquid core, if it actually does have fault lines and plate tectonics, and figure out the Red Planet’s basic internal structure. All of this will not only help scientists understand Mars, but also to gain insight on how terrestrial planets form and evolve.

“We’re very confident that this will produce exciting science,” said John Grunsfeld, NASA’s associate administrator for the agency’s Science Mission Directorate.

InSight won out for this round of NASA’s lowest cost missions, the Discovery missions, over two other very enticing proposals: the Titan Mare Explorer (TiME) would have sent a floating high-tech buoy to land in a methane sea on Saturn’s moon Titan to study its composition and its interaction with the atmosphere; and Chopper was a proposed Comet Hopper mission that would put a lander on comet 46P/Wirtanen where it would study the comet’s composition, and with thrusters it could essentially “hop” to different locations on the comet.

While all three missions in the competition were compelling, NASA only has enough money, unfortunately, for one Discovery mission in 2016. And, Grunsfeld said, InSight was the best choice of a project that could stay at or even under the Discovery program’s $425 million cost cap, excluding launch costs, and keep its tight schedule to launch in 2016.

“Our Discovery Program enables scientists to use innovative approaches to answering fundamental questions about our Solar System in the lowest cost mission category,” said Grunsfeld. “InSight will get to the ‘core’ of the nature of the interior and structure of Mars, well below the observations we’ve been able to make from orbit or the surface.”

Asked during a press briefing if NASA is becoming, too Mars-centric, Grunsfeld replied, “We still have a broad portfolio of missions, with Juno recently launching, OSIRIS-Rex launching in 2016, the Dawn mission going on and New Horizons heading to Pluto, so I think we’ve shown very broad diversity in past selections.”

Grunsfeld was also asked if the Curiosity rover’s recent successful landing had any influence on the choice, but Grunsfeld said the decision was actually made before the Mars Science Laboratory rover touched down.

“We’re really clueless on the interior of Mars,” said NASA’s Planetary Science Chief, Jim Green. “And this is really our first attempt to understand what terrestrial bodies go through in their early evolution.”

Insight’s body is based on the Phoenix lander, which landed in Mars’ polar region in 2008, and will use solar panels for power instead of a radioisotope power system, which saves on costs. But the instrumentation for InSight is completely different than Phoenix, and it involves an international mix.

InSight will carry four instruments: JPL will supply a geodetic instrument to determine the planet’s rotation axis and a robotic arm and two cameras used to deploy and monitor instruments on the Martian surface. The French space agency CNES is leading an international consortium that is building an instrument to measure seismic waves traveling through the planet’s interior. The German Aerospace Center (DLR) is building a subsurface heat probe to measure the flow of heat from the interior.

And don’t expect any great color photos of Mars’ surface from InSight. It will only have a black and white context camera, and Green said they don’t expect any changes in that regard, as the mission will need to stay on budget and on time.

InSight will land in a flat, equatorial, flat region in September 2016 to begin a two-year scientific mission. “The Phoenix lander went to polar regions and we knew it was going to be a short lifetime,” said Grunsfeld. “Because InSight goes to an equatorial region where the environment is relatively more benign, it has the potential to last longer, so that is exciting.”

Green touched on other potential areas of study for InSight, such as determining if there are “Marsquakes,” and whether the landslides seen by the Mars Reconnaissance Orbiter’s HiRISE camera are due to activity on the planet like quakes or from melting.

“Methane is being potentially being produced from Mars’ interior,” Green said, “and that touches upon the potential life question. But that is a potentially active process a-bioticaly, in interactions between water, minerals and magma. And this mission could determine if Mars has a hot interior magma, and why it doesn’t generate a magnetic field. What we are seeing are some of the different perspectives of Mars being an active planet or not, and these instruments will clearly be able to do this.”

Sources: NASA, press briefing