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Emily LakdawallaNovember 15, 2013

Answers to Frequently Asked Questions about MAVEN's launch and mission

MAVEN is just about to launch! The spacecraft is atop the rocket on the launch pad at Kennedy Space Center, Florida, and liftoff is currently scheduled for Monday, November 18, at 1:28 p.m. local time (10:28 PT / 18:28 UT). On Wednesday, the mission released their launch press kit. I've said it before and I'll say it again: before you ask anybody any questions about any NASA mission, look for the press kit. Odds are good your question is answered inside, in language you can understand. But in case you don't have time for that, this post paraphrases and summarizes the press kit's high points, and hopefully answers most of your questions.

Questions About Launch Day

What kind of rocket is it? It's an Atlas V-401. The "401" bit tells you the following: it's a 4-meter nosecone (the other common option is a 5-meter one). There are no extra solid rocket boosters strapped on to the sides. And there's one upper rocket stage, a Centaur. For comparison, Curiosity launched on an Atlas V-541 (5-meter fairing, 4 strap-on boosters, and a partridge in a pear tree, I mean a Centaur).

MAVEN atop its Atlas V, November 8, 2013

NASA / Kim Shiflett

MAVEN atop its Atlas V, November 8, 2013

What's the launch timeline? If all goes well, the spacecraft will be on its own and on the way to Mars within an hour after launch. All times are Pacific/UT. Each launch day has a two-hour launch window, so these times may need to be adjusted if the spacecraft doesn't launch right when the window opens.

What happens if they don't launch on Monday? The launch period lasts 20 days, and could even be extended out to December 23 if necessary.

For more specifics about the timeline of events on launch day, it's worth checking out the United Launch Alliance website and booklet on the MAVEN launch.

Questions about the spacecraft

What are its basic dimensions? Its body is a squat square box, 2.29 meters square and 1.5 meters high. The high-gain antenna is 2 meters in diameter (think about that; it's big). Its solar panels span a total of 11.43 meters and are in a "gull-wing" shape. When the spacecraft is all packed up for launch, with the solar panels folded, it's 3.47 meters high. Four instrument booms will extend outward from the bus: one for the SWEA instrument (1.65 meters long), one for the articulated payload platform (2.3 meters long), and two for the LPW instrument (7 meters long).

The launch mass is 2,454 kilograms, of which 1,645 kg is fuel and only 809 is spacecraft. Of that, the instrument package weighs in at 65 kilograms, and there's an additional 6.5 kilograms devoted to the Electra instrument that allows relay from rovers and landers to Earth.

MAVEN at Mars

NASA / GSFC

MAVEN at Mars

Questions about the science

What is MAVEN's mission? The main questions MAVEN is seeking to answer is: how did Mars lose its early atmosphere, and how does atmospheric loss continue today? To do that, "MAVEN will study the boundary between the planet’s current atmosphere and outer space, measuring solar energy inputs to the atmosphere, the composition of the upper atmosphere, and the current rates of loss of atmospheric gas to space. Information about these escaping gases’ chemical, atomic and energetic character will inform scientists about the processes at work." The mission has three stated objectives:

The mission is led by Principal Investigator Bruce Jakosky.

Diagram of MAVEN instrument locations

NASA / LASP / GSFC / JPL

Diagram of MAVEN instrument locations
Six instruments comprise the Particles and Fields package: Solar Energetic Particle (SEP); Solar Wind Ion Analyzer (SWIA); Solar Wind Electron Analyzer (SWEA); SupraThermal and Thermal Ion Composition (STATIC); Langmuir Probe and Waves (LPW); and Magnetometer (MAG). There is also an Imaging UltraViolet Spectrograph (IUVS) and a Neutral Gas and Ion Mass Spectrometer (NGIMS).

What science instruments are on MAVEN? There are eight instruments. Six of them are integrated into a "Particles and Fields package":

Two more instrument packages are on the articulated payload platform, which continuously rotates as MAVEN orbits in order to keep the instruments pointed correctly at all times -- except for a five-hour period twice each week when the spacecraft turns to Earth to relay data through its high-gain antenna.

The Remote Sensing package contains one instrument, the Imaging UltraViolet Spectrograph (IUVS). It will study Mars' atmospheric composition from afar, looking across the limb while close to Mars and imaging the whole disk when far from Mars. It will also observe the occultation of stars by the atmosphere to measure carbon dioxide abundance. Many missions have flown similar instruments, including UVIS on Cassini at Saturn. IUVS is co-led by Nick Schneider and Bill McClintock.

The Neutral Gas and Ion Mass Spectrometer (NGIMS) is also its own instrument package. It will measure the composition of neutral gases and ions in the upper atmosphere, including helium, nitrogen, oxygen, carbon monoxide, argon, and carbon dioxide. It will also measure the isotopic ratios for carbon, nitogen, oxygen, and argon. NGIMS will be able to gather data at altitudes of 125 to 400 kilometers. MAVEN will spend 12 minutes at those altitudes on each orbit. NGIMS is led by Paul Mahaffy, who also leads the mass spectrometer instrument on Curiosity (SAM).

Isn't there a camera? No.

What can MAVEN tell us about methane on Mars? None of MAVEN's instruments can measure methane in Mars' atmosphere. That's up to India's Mars Orbiter Mission and ESA's future ExoMars Trace Gas Orbiter.

If your curiosity about MAVEN still isn't satisfied, read the rest of the launch press kit for yourself!

Read more: mission status, explaining technology, MAVEN, spacecraft

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Emily Lakdawalla

Senior Editor and Planetary Evangelist for The Planetary Society
Read more articles by Emily Lakdawalla

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