The MAVEN team includes experts from many institutions and disciplines. The team blog is a forum for these individuals to share their personal experiences with the MAVEN community. From exploring the science of the mission, to the engineering behind the instrumentation, from the complex aspects of project management, to the access and use of data products, we hope you enjoy the opportunity to engage with the MAVEN team through these anecdotes.
Rob Lillis is an Associate Research Physicist at the University of California Berkeley Space Sciences Laboratory, a member of the MAVEN Science team and the deputy lead for the Solar Energetic Particle instrument.
Why is the surface of Mars no longer habitable?
Sounds like a straightforward question, right? However, those nine words comprise one of the most vexing questions in planetary science. There is now overwhelming evidence that Mars was once a place where liquid water flowed on the surface and, thus, life as we know it could have thrived, at least episodically. Orbiters have identified branching networks of valleys that most likely were carved by rainwater or snowmelt. Rovers have driven through ancient streambeds and found minerals that can only be formed over many years underwater. However, such stable surface water requires an atmospheric surface pressure much higher than today’s ~7 millibars (<1% of Earth’s pressure) to prevent evaporation and cause greenhouse warming.
Where did this ancient atmosphere go? If it had all been absorbed back into the crust, abundant carbonate minerals should exist on or near the surface. However, extensive surveys of Mars from orbit have revealed very little carbonate, not nearly enough to account for all the carbon dioxide that has been lost. The only other explanation: The atmosphere escaped out to space over billions of years. But how did this happen? What physical processes drove the escape? How did they vary over time as solar radiation and the solar wind buffeted Mars’ atmosphere, which lacked the protection of a global magnetic field? And, most importantly, how much total atmosphere escaped over Mars’ history?(Read more»)
Based upon the 2016 Planetary Mission Senior Review Panel report, NASA this week directed nine extended missions, including MAVEN, to plan for continued operations through fiscal years 2017 and 2018. Final decisions on mission extensions are contingent on the outcome of the annual budget process.
In addition to MAVEN, other missions receiving NASA approval for extensions, contingent on available resources, are: New Horizons, Dawn, the Mars Reconnaissance Orbiter (MRO), the Opportunity and Curiosity Mars rovers, the Mars Odyssey orbiter, the Lunar Reconnaissance Orbiter (LRO), and NASA’s support for the European Space Agency’s Mars Express mission.
Read the full NASA feature: http://go.nasa.gov/29dbXgj(Read more»)
MAVEN began its fifth “deep dip” campaign of the mission this week. Three maneuvers were successfully carried out to lower the periapsis (or lowest) altitude of the spacecraft by approximately 29 kilometers (18 miles), placing MAVEN into the targeted density corridor, where the average density of Mars’ atmosphere is 3.0 kg/km³. The fifth deep dip for MAVEN is uniquely located over the solar terminator (the boundary between dayside and nightside), close to the ecliptic plane, and at a Martian latitude of 35ºN.
The three maneuvers—carried out on June 7 & 8—required a total ∆V of 4.6 m/s and resulted in a periapsis altitude of ~119 km (74 miles). The purpose of the MAVEN deep dip campaigns is to sample a full range of altitudes within the upper atmosphere of Mars, providing complete coverage. At 119 km, MAVEN reaches the Martian homopause, which is the lower, well-mixed region of Mars’ upper atmosphere, where the density is about thirty times greater than at periapsis during a typical science orbit.(Read more»)
— MAVEN Principal Investigator Bruce Jakosky
As of today, MAVEN has been in orbit around Mars for one Earth year! And it’s been an action-packed year.
Some of the highlights include:
- Getting into orbit!
- Surviving the encounter with Comet Siding Spring
- Commissioning the spacecraft
- Carrying out ten months (so far) of observations during our primary mission
- Carrying out four deep-dip campaigns
The success of the mission so far is a direct result of the incredibly hard work of everybody who works (and has worked) on MAVEN. This one year at Mars reflects the tremendous efforts over the preceding dozen years. And the mission continues—we still have two months to go in our primary mission, and then we begin our extended mission. We’re obtaining an incredibly rich data set that is on track to answer the questions we originally posed for MAVEN and that will serve the community for a long time to come.
I hope everybody is as proud of what we’ve accomplished as I am! And here’s to the next year of exciting observations, analyses, and results!(Read more»)
MAVEN completes fourth deep-dip campaign
NASA’s MAVEN spacecraft, in orbit at Mars since Sept. 21, 2014, has completed the fourth deep-dip campaign of its primary science mission. The series of five-day campaigns are designed to lower the periapsis (lowest altitude) of the spacecraft above Mars in order to achieve a targeted atmospheric density corridor and to sample the lower, well-mixed portion of the Martian upper atmosphere. The density at 125 km (78 mi) can be 30 times that encountered during the nominal science orbits, where the periapsis is approximately 150 km (93 mi).
The latest deep-dip campaign began on Sept. 2nd with two “walk-in” maneuvers that lowered the periapsis of the spacecraft to 121 km (75 mi) above the Martian surface. These maneuvers had ∆V (delta-V or a change in velocity) magnitudes of 2.7 m/sec and 0.6 m/sec. The campaign concluded in the early hours of Sept. 10th with the second of two “walk-out” maneuvers, designed to raise the periapsis of MAVEN back to near 150 km. The maximum atmospheric density encountered during the deep-dip was 3.0 kg/km³.
The two “walk-out” maneuvers (executed on Sept. 9 & 10) had ∆V magnitudes of 3.3 m/sec and 0.6 m/sec, and raised the periapsis by 20 km (12 mi) and 4 km (2.5 mi) respectively. These maneuvers returned MAVEN to a nominal periapsis altitude of 145 km (90 mi) and achieved an estimated density of 0.11 kg/km³.(Read more»)