University of Colorado Laboratory for Atmospheric and Space Physics Archives

by Nur Hussein, staff writer Huge cheers just went up across the nation as NASA's MAVEN probe successfully transitioned from its heliocentric orbit to an elliptical, 35-hour orbit around Mars! It was a nail-biting 33 minutes as the probe autonomously reversed itself and initiated a burn from its 6 main engines, in order to slow itself enough for Mars' gravitational field to be able to ''catch" it. Part of this maneuver caused MAVEN's high-gain antenna to be temporarily pointed away from Earth. Because it takes signals 12.5 minutes to reach Mars from Earth (and at a data rate of 40 bps: no mistake! Forty bits per second!) using the low-gain antenna, there was no way for MAVEN's teams to give it any assistance or corrections; the intrepid little orbiter did it on her own. On November 18, 2013, the Atlas V 401 rocket carrying the MAVEN (Mars Atmosphere and Volatile Evolution) space probe took off from Cape Canaveral and started its trek into the inky void of space towards Mars. Its mission is to study the Martian atmosphere to determine, among other things, how the once-abundant supply of water on Mars was lost over the ages. Today, the MAVEN spacecraft has crossed 442 million miles and successfully reached Mars and is in orbit around the red planet. One of the biggest challenges for the probe was actually getting it into orbit around Mars. With the spacecraft traveling at intensely high speeds, almost doubling in velocity in the last few hours before transition, it needed to reduce its velocity from about 12,800 MPH to approximately 10,000 MPH before it was captured by the Martian gravitational field. To do this, it had to fire its thrusters in the opposite direction and burn fuel for about 33 minutes. Its initial orbit is now an elongated 35-hour orbit. Tim Priser, chief spacecraft systems engineer at Lockheed Martin explained that MAVEN's burn was, "a little bit underperforming, relative to predictions," and so it burned for a little longer than expected tonight. Over the next couple of weeks, MAVEN will initiate 5 more short burns to adjust its orbit, and will ultimately settle into a 4.5-hour orbit, which will be almost circular. Once it achieves that tighter orbit, the teams will deploy MAVEN's science instruments, and the main body of research will begin. But MAVEN hasn't been sitting idle as she traveled. She's been gathering data on the solar winds between Earth and Mars, because it's thought that these winds are a significant factor in what happened to the atmosphere and water on Mars. It's a huge collaboration between industry, academia, and government. Lockheed Martin Denver managed the engineering of the probe. JPL is in charge of monitoring navigational and telemetry data. The onboard instrumentation for MAVEN was built by three different facilities; the UC Berkeley Space Sciences Laboratory built the Particles and Field (P&F) package, the University of Colorado Laboratory for Atmospheric and Space Physics built the Remote Sensing (RS) package, and the Goddard Space Flight Center built the Neutral Gas and Ion Mass Spectrometer (NGIMS) package. MAVEN will determine how much of the Martian atmosphere has been lost over time by measuring the current rate of escape to space and gathering enough information about the relevant processes to allow extrapolation backward in time. In addition to gathering data for this main focus of study, MAVEN will get a rare, up-close look at a comet as it passes by Mars, at about one-third the distance from Mars to Earth. As a safety precaution, MAVEN will be on the other side of Mars when the comet makes its closest approach, but MAVEN will get plenty of chances to gather data about the comet and its effect on Mars' atmosphere. With any luck, MAVEN won't be alone in orbit for long. India has another probe named MOM (Mars Orbiter Mission) on its way, and set to make Martian orbit in November 2014. MOM's study will also focus on the Martian atmosphere, searching for the signature of methane (CH4) in the Martian atmosphere, which has previously been detected from Martian orbit and telescopes on Earth. CH4 has a short lifetime in the Martian atmosphere, meaning that some source on the Mars must replenish it. About 95% of the methane on Earth is produced by microbes, so there is some speculation that Mars may be hiding a biosphere beneath its surface. Geologic processes can also produce methane, so that's another intriguing line of questioning. Update David Mitchell, MAVEN's project manager, said at NASA's press conference, "This was a very big day for MAVEN. We’re very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet. The commissioning phase will keep the operations team busy for the next six weeks, and then we’ll begin, at last, the science phase of the mission. Congratulations to the team for a job well done today ... You get one shot with orbital insertion, and MAVEN nailed it tonight We’re really happy for the crew and their families ... things looks great with the orbit a this point ... Duration of the burn was 34 minutes, 26 seconds: about 11 seconds longer than nominal. The observed navigational data is all within the nominal range, and tracking data shows we’re in a stable orbit. In the next couple of days, we’ll do our second burn. I'm looking forward to that." Asked whether the riskiest parts of the mission were over, Mitchell added, "I personally will breathe a lot easier come November 8, once the science starts and we can see that everything is working." “NASA has a long history of scientific discovery at Mars and the safe arrival of MAVEN opens another chapter,” said John Grunsfeld, astronaut and associate administrator of the NASA Science Mission Directorate at the agency’s Headquarters in Washington. “Maven will complement NASA’s other Martian robotic explorers—and those of our partners around the globe—to answer some fundamental questions about Mars and life beyond Earth.” MAVEN's principal investigator, Bruce Jakosky said, "I think my heart’s about ready to start again! We’ve been developing this mission for about 11 years now, and I can’t tell you how this flawless performance tonight ... It’s a real testament to the team. We’ve had over 600 people working on MAVEN over the course of its life ... They have put their heart and soul into doing each and every task that helped us get here tonight ...We are anxiously awaiting the arrival in 2 days of the Indian MOM mission. We wish them all the best luck from everyone on the MAVEN team." Over the next 6 weeks, the various teams will commission the spacecraft, deploy the booms, which have instruments that must be turned on, tested, and calibrated, and will be sending and receiving data from the Curiosity rover. MAVEN then will begin its one Earth-year primary mission, taking measurements of the composition, structure and escape of gases in Mars’ upper atmosphere and its interaction with the sun and solar wind. As MAVEN goes through her walk-down manuevers, her orbit height will go from periapsis (lowest orbit altitude) of 93 miles (150 kilometers) to about 77 miles (125 kilometers). She'll be collecting atmospheric data as her altitude changes, which will show where the upper and lower atmospheres meet, giving scientists a full profile of the upper tier. On October 19, 2014, Comet Siding Spring (C/2013 A1) will pass Mars at a distance of only 82,021 miles (132,000 kilometers). MAVEN will take 5 days, centered on the comet's closest approach, to observe and record the comet's effects on the Mars environment. The press conference ended with a question from Twitter user. Are there any superstitions that the MAVEN team observes? Mitchell replied, "It's a common tradition to bring peanuts to launches and orbital insertions. Peanuts are good luck. This mission, Mars bars. I think we may adopt that as a new tradition!" Congratulations to all of MAVEN's teams for this breathtaking achievement! Despite the fact that we've been in space for decades, it's still amazing every time. Having a spacecraft put itself into planetary orbit sounds so much like science fiction brought to life. -30-

NASA MAVEN Rendezvous With Mars

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