Mission News and Events

Aug 22, 2014: Graduate student Beatriz Gallardo won first place for her student poster in Thermosphere-Ionosphere at the 2014 CEDAR (Coupling, Energetics and Dynamics of Atmospheric Regions) Workshop. Her poster utilized THEMIS data and was titled "Ionospheric Flow Structures Associated with Auroral Beading at the Substorm Auroral Onset." Gallardo's work showed that extremely large, small-scale flows develop in precise association with each auroral bead (strong intensification) that is seen along the brightening auroral arc at substorm onset. This demonstrates critical features of the physics of the substorm onset process.

Aug 22, 2014: Dr. Toshi Nishimura of AOS/UCLA received the Obayashi Young Scientist Award from Japan's Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS). Toshi received this award as a result of his ground-breaking research on a variety of topics, including energy flow to and from the ionosphere within the inner magnetosphere; fundamental, long-standing questions on the processes leading to an causing substorms; and the causes and magnetospheric source regions of pulsating and diffuse aurora, using THEMIS ASI data.

Aug 22, 2014: THEMIS scientist Dr. Wen Li won a Young Scientist Award from the International Union for Radio Science (URSI) and she was ranked as the #1 URSI young scientist from the US. She has also been elected as the Early Career Representative for Commission H in URSI and will be serving for the community for the next six years. In her new role, she will to help promote young scientists and help the Chair and Vice-Chair write Radio Science Bulletin.

May 10, 2014: Emmanuel Masongsong of the THEMIS-ARTEMIS education team at UCLA was contacted by Ian Schofield of Athabasca University in Canada: Ian's group was purchasing UCLA magnetometers with which to significantly expand their network across the Hudson Bay in northern Quebec and he wanted outreach materials that would help share their research with the surrounding communities. He had done some presentations and realized how excited people were about their unique local science of the aurora. Ian is pioneering an outreach program at the new magnetometer sites, many of which consist of fly-in-only villages of Native peoples, and educating students and families all across Quebec who had never even heard of space weather. Emmanuel had compiled lots of THEMIS/ARTEMIS/aurora/reconnection videos and made posters and handouts which Ian could translate and adapt for his purposes. Excitingly, these materials will become trilingual, translated into Inuit and French, and presented all across Canada, bringing the story of THEMIS and ARTEMIS to the far reaches of North America! Thus, in addition to expanding the THEMIS ground-based observatory network, Ian and his group are actively engaging people in remote villages, schools and the general public about space weather and the importance of having widespread measurements of these elusive phenomena.

Mar 6, 2014: NASA’s THEMIS Discovers New Process that Protects Earth from Space Weather. Now, for the first time, a study shows that in certain circumstances a pool of dense particles normally circling Earth, deep inside the magnetosphere, can extend a long arm out to meet – and help block – incoming solar material.

Mar 7, 2014: Science Magazine Publishes Research Paper by THEMIS Scientists Science magazine published a research paper by THEMIS scientists Brian Walsh, John Foster, Phil Erickson and David Sibeck about the persistent interaction of the plasmaspheric plume with the dayside magnetopause, in the presence of dayside reconnection. The results, from THEMIS and GPS-TEC measurements and have made news around the world. Read the paper. See the press release from MIT.

September 27, 2013: THEMIS-ARTEMIS Principal Investigator Vassilis Angelopoulos is first author on a paper published in the today's issue of Science magazine: Electromagnetic Energy Conversion at Reconnection Fronts, in which he discusses how eight satellites that were temporarily aligned in space last year in the night-side of Earth’s magnetic shield have given scientists their most complete picture yet of the locales of intense energy interactions between the Sun and Earth called substorms.

May 16, 2013: From NASA’s Lunar Science Institute: Led by postdoc Andrew Poppe at the University of California at Berkeley, NLSI’s DREAM scientists have used recent data from NASA’s twin probe ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun) mission to investigate the thin neutral atmosphere surrounding the Moon by looking at the trajectories of ions originating from the lunar atmosphere. These ions were detected by ARTEMIS while the Moon crossed Earth’s geomagnetic tail, where the Moon is protected from the energetic blast of solar wind particles. Read more at www.nasa.gov/mission_pages/themis/news/six-years_prt.html

February 19, 2013: THEMIS launched on Feb. 17, 2007, with five nearly identical spacecraft nestled inside a Delta II rocket. Simply orchestrating how to expel each of the five satellites without unbalancing the rocket was an engineering tour de force – but it was only the preamble. Over time, each spacecraft moved into formation to fly around Earth in a highly-elliptical orbit that would have them travelling through all parts of Earth's space weather environment, a giant magnetic bubble called the magnetosphere. With five different observatories, scientists could watch space weather unfold in a way never before possible. In its sixth year in space, scientific papers using THEMIS data helped highlight a number of crucial details about what causes space weather events in this complex system. Read more at www.nasa.gov/mission_pages/themis/news/six-years_prt.htm

June 26, 2012: The editors of the Journal of Geophysical Research - Space Physics have selected Jenni Kissinger's recent paper, entitled "Diversion of plasma due to high pressure in the inner magnetosphere during steady magnetospheric convection," as both a JGR Editor's Highlight and a feature in the "Research Spotlight" section on the back page of Eos, AGU's weekly newspaper.

June 7, 2012: Congratulations to Lunjin Chen for winning the Fred L. Scarf award for the best 2011 PhD thesis in AGU's Space Physics and Aeronomy section, recognizing outstanding dissertation research that contributes directly to solar-planetary science. His thesis, entitled "Propagation and Excitation of Electromagnetic Waves in the Earth's Inner Magnetosphere," benefited significantly from the availability of THEMIS data. He will be receiving his award at the Fall AGU meeting.

May 1, 2012
A THEMIS/ARTEMIS mission spacecraft (P1) and Jimmy Raeder's simulation rendition of a THEMIS major conjunction are prominently featured on the cover of today's (March 16, 2012, Vol. 39, No. 5) issue of Geophysical Research Letters.
Photo Credit: J. Raeder (UNH) NASA/Goddard SVS

January 29, 2012: Congratulations to Drew Turner for his Nature Physics publication on: "Explaining sudden losses of outer radiation belt electrons during geomagnetic storms" published on-line on January 29 and making the news around the world! Using combined data from THEMIS, GOES, and NOAA-POES satellites, Dr. Turner's research explains how electron losses through the magnetopause resolve a long standing mystery of electron drop-outs during storm main phase.
Read the article here: http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2185.html
NASA press release: http://www.nasa.gov/mission_pages/themis/news/electron-escape.html

January 17, 2012: The editors of the Journal of Geophysical Research - Space Physics have selected Dr. Larry Lyons' recent paper, entitled "Possible connection of polar cap flows to pre- and post-substorm onset PBIs and streamers" as an AGU "Research Spotlight." A general summary of the paper was published in JGR online and in the “Research Spotlight” section on the back page of Eos, AGU's weekly newspaper.

July 17, 2011 - Second ARTEMIS Spacecraft Successfully Enters Lunar Orbit
The ARTEMIS P2 spacecraft was successfully inserted into lunar orbit at 8:24 PM ET on July 17, 2011. The insertion process took three hours and 20 minutes and was overseen by flight engineers from NASA Goddard, UC Berkeley, and NASA's Jet Propulsion Lab. Over the next three months a series of period reduction maneuvers will move the spacecraft into an orbit of 27.5 hours, similar to the P1 orbit but moving in the opposite direction.
The two ARTEMIS spacecraft are healthy and are expected to continue to return science data for several years. The satellites will fly close to the lunar surface once per orbit – approaching anywhere from within 12 to 240 miles of the surface depending on the iteration – in a belt ranging 20 degrees above and below the equator.
For full story click here.

July 4, 2011 - Mission News: THEMIS/ARTEMIS - Firsthand account from Bryce Roberts:
This week, the ARTEMIS mission operations team has been practicing and preparing for the second lunar orbit insertion (LOI), this time for ARTEMIS P2, this coming Sunday. Moments ago, we just completed our dress rehearsal to make sure everyone on the team is sharp on all the procedures that will need to be executed this Sunday. Tomorrow (Friday) and Saturday we will be preparing the actual command loads that will perform the maneuver; Friday's product will be an initial "pretty good" solution, and Saturday's product will be the latest, greatest, most accurate we can generate. Fortunately, the LOI maneuver on Sunday happens during daylight hours. Much better than starting out at 5AM! I hope to have a great update for you all next week. Wish us luck!
--Bryce Roberts, on behalf of the THEMIS and ARTEMIS Mission Operations Team

June 28, 2011 - First ARTEMIS Spacecraft Successfully Enters Lunar Orbit
The first of two ARTEMIS ("Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun") spacecraft is now in its lunar orbit.
On June 22, ARTEMIS P1 began firing its thrusters to move out of its kidney-shaped "libration" orbit on one side of the moon, where it has been since January. Three successive maneuvers were used to kick the spacecraft out of its orbit and send it on a trajectory toward the moon.
It continued on that path until June 27 at 10:04 a.m. EDT when the spacecraft was about 2,400 miles from the moon. At that point, flight engineers at UC Berkeley issued the first commands to move it into orbit around the moon. Two more maneuvers helped fine-tune the position, and as of 12:30 p.m. EDT, ARTEMIS P1 is now in lunar orbit.
For full story click here.

June 23, 2011 - ARTEMIS Spacecraft Prepare for Lunar Orbit
They've almost arrived.
It took one and a half years, over 90 orbit maneuvers, and – wonderfully – many gravitational boosts and only the barest bit of fuel to move two spacecraft from their orbit around Earth to their new home around the moon.
Along their travels, the spacecraft have been through orbits never before attempted and made lovely curlicue leaps from one orbit to the next. This summer, the two ARTEMIS spacecraft -- which began their lives as part of the five-craft THEMIS mission studying Earth's aurora – will begin to orbit the moon instead. THEMIS is an acronym for the Time History of Events and Macroscale Interaction during Substorms spacecraft.
For full story, click here.

March 11, 2011: THEMIS data were prominently presented during the recent AGU Chapman conference on the Relationship between Auroral Phenomenology and Magnetospheric Processes, held in Fairbanks, Alaska, from February 27th through March 4th, 2011. The conference provided a forum to present the latest results from analyses of experimental data (including space-borne, ground-based and co-ordinated data), simulation, and theory, addressing various aspects of the aurora. Presenters aimed to connect our knowledge of auroral morphology and mechanisms to candidate physical processes in the magnetosphere capable of powering and structuring the aurora on Earth and other planets. More details at: http://www.agu.org/meetings/chapman/2011/bcall/

October 27, 2010 - Dead Spacecraft Walking
A pair of NASA spacecrafts that were supposed to be dead a year ago are instead flying to the Moon for a breakthrough mission in lunar orbit.
"Their real names are THEMIS P1 and P2, but I call them 'dead spacecraft walking,'" says Vassilis Angelopoulos of UCLA, principal investigator of the THEMIS mission. "Not so long ago, we thought they were goners. Now they are beginning a whole new adventure."
For full story click here.

October 22, 2010 - ARTEMIS Spacecraft Believed Struck by Object
Flight Dynamics data from THEMIS-B (one of the two ARTEMIS spacecraft) indicated that one of the EFI (electric field instrument)spherical tip masses may have been struck by a meteoroid at 0605 UT on October 14. All science instruments continue to collect data. The probe and science instruments aboard the spacecraft continue to operate nominally. The upcoming insertion into Lissajous orbit will not be interrupted.
For full story click here.

September 13, 2010 - ARTEMIS - The First Earth-Moon Libration Orbiter
In August 1960, NASA launched its first communications satellite, Echo 1. Fifty years later, NASA has achieved another first by placing the ARTEMIS-P1 spacecraft into a unique orbit behind the moon, but not actually orbiting the moon itself. This type of orbit, called an Earth-Moon libration orbit, relies on a precise balancing of the Sun, Earth, and Moon gravity so that a spacecraft can orbit about a virtual location rather than about a planet or moon. The diagrams below show the full ARTEMIS-P1 orbit as it flies in proximity to the moon.
For full story click here.

Dec 18, 2009: Update from Mission Ops: We've been gradually raising the orbits of the two outermost probes (THEMIS B and THEMIS C) as part of a long term plan to send them both to the moon. The thrusters on our spacecraft are not very powerful, so we can't just light the fuse and fly directly there... it's a much slower and more indirect process that uses gravitational assistance from the earth and the moon to do the hard work, and sometimes it seems almost endless. But on December 8th, we were finally rewarded for all our methodical progress and patience. Thanks to the advanced planning of our navigation team here at Berkeley, working with groups at Jet Propulsion Laboratory and Goddard Space Flight Center, THEMIS B arrived at an apogee (highest part of the orbit) right as the moon was in the neighborhood. We didn't go into orbit around the moon right then and there (that would be impossible) but the moon's gravitational pull significantly changed the orbit of the probe and put us on the path to eventually travel to the moon and stay there, later next year. We called the December 8th encounter "the knee", because the track of the orbit, which normally looks like a flat oval, has a knee- like bend in it.

Dec 14-19, 2009: American Geophysical Union (AGU) meeting: THEMIS scientists and Education Specialists attended the American Geophysical Union (AGU) meeting in San Francisco, CA. THEMIS was well represented at AGU, and had a successful press release (see the NASA article: http://www.nasa.gov/mission_pages/themis/news/auroras-collide.html). After the AGU meeting, the THEMIS science, engineering, and education team convened to talk about the status of the mission, plans for submitting future funding to NASA to continue THEMIS science and education, and new research results.

Dec 4, 2009: THEMIS completed its End Of Prime Mission (EOPM) review with high accolades from NASA/HQ and GSFC. The objective of the review was to demonstrate achievement of the prime mission* science objectives, adherence to the mission Level-1 requirements, and to report on overall mission technical performance. It gave us the opportunity to showcase the excellent science accomplishments and superb performance of the instruments and mission. NASA Headquarters stated how impressed they were with both the THEMIS science results and the THEMIS team's support of the community with data and with analysis tools. Congratulations to the team for such an exemplary performance!

*prime mission: the part of the mission that includes the design, planning, building and deployment of the spacecraft and instruments, ending when the mission fulfills its scientific objectives. (see the THEMIS Education and Public Outreach PDF for information on the THEMIS Education Program over this prime mission) - Click here (PDF, 426KB).

Sept 25, 2009: Update from Mission Ops: Sunday the 13th was a big day for THEMIS. We did our fifth and final orbit raise maneuver for THEMIS B (recall that THEMIS B was the probe that already had the longest orbit, which is why only five orbit raise maneuvers were required). This final maneuver was very carefully designed and timed so that right as THEMIS B came to its apogee (highest point of the orbit) it would get within about 40,000 kilometers of the moon. This happened just as planned on Wednesday, and the gravitational pull of the close approach to the moon helped raise THEMIS B's orbit even more.

THEMIS B is still in earth orbit and the moon has now moved away, so we still have a long way to go. But THEMIS B's apogee is now about equivalent to the distance from the earth to the moon -- and we can still receive low data rate telemetry and send commands from our own ground station. This means that once THEMIS B and C go into permanent orbit around the moon in 2011, we'll still be able to talk to them directly from Berkeley, even though we'll have access to the larger dishes that are part of NASA's Deep Space Network.

Sept 4, 2009: Update from Mission Ops: Although we're still busy with the orbit raise maneuvers that will ultimately send THEMIS B and C on their way to the moon, the workload is easing somewhat. That's because we do a maneuver only every other orbit and the orbits are getting longer, so the maneuvers are getting farther apart in time. It's now about two weeks between maneuvers on THEMIS B and one week between maneuvers on THEMIS C.

Aug 21, 2009: Update from Mission Ops: Things continue to go smoothly in our campaign of orbit raise maneuvers on THEMIS B and THEMIS C. Each time we do an orbit raise maneuver, the orbital period gets longer, so now THEMIS B only comes back close to earth once every six days (it used to be every four). Because we only do our orbit raise maneuvers when the spacecraft are at their closest point to earth, that means we have longer and longer to wait between maneuvers, making our workload gradually lighter.

Aug 7, 2009: Update from Mission Ops: Do You Have the Time? We've been very busy! Less than a day after the 40th anniversary of the Apollo 11 moon landing, we did the first orbit raise maneuver which will eventually see THEMIS B and THEMIS C in orbit around the moon in 2011. Since starting, we've done 10 separate maneuvers between THEMIS B and THEMIS C, each of which gradually raises the apogee (the highest point in the orbit). We've done this kind of activity in 2007 when we moved the probes into their prime science orbits, but what's different this time is that if anything goes wrong, the entire lunar targeting plan has to be reworked. So we're taking every precaution to make sure there will be no errors (we've now done 306 separate maneuver operations, with plenty of lessons learned along the way). So far, so good. Everything's going smoothly!

July 17, 2009: Update from Mission Ops: One Small Step for the Orbit Raise Maneuver: The first orbit raise maneuver in the campaign that will ultimately send THEMIS B and C to the moon starts next Monday, just before midnight. That's 40 years and a fraction of a day after Neil Armstrong and Buzz Aldrin landed on Apollo 11.

May 12, 2009: Check out this Space Storms video produced by the Austrailian Broadcasting Corporation network. John Bonnell (THEMIS) and Stu Bale (STEREO) as well as the Berkeley Mission Operations Center are featured prominently. Thanks to John Bonnell, John McDonald, the Mission Ops team and the many members of the UCB who contributed their time and made the filming a success.
A transcript of the story is available here (PDF, 39KB).

May 5, 2009: Update from Mission Ops: Things have been progressing nicely for us. We've conducted several maneuvers over the past weeks -- all of them more or less routine, since we've done 294 of them to date! But this morning's maneuver on THEMIS C (the second-outermost spacecraft) had a special significance: It is the last maneuver of this spacecraft until later this summer... when we start to raise its orbit all the way to the moon! For full article click here (PDF)

February 28, 2009: Yet another quiet week in THEMIS Operations Land, at least as far as operating the satellites goes. However, on 24 Feb, the UC Berkeley flight dynamics team -- as well as our partners at JPL and Goddard -- presented for review the technical details of our plan for sending two of the five THEMIS probes to the moon. The presentation was well received and we were given the go-ahead by NASA! Another tiny "checkup" review remains to be completed in mid-May, and the kick off of the process will start in early July of this year.

February 18, 2009: Below is a message from Vassilis Angelopoulos, Pricipal Investigator of the THEMIS Mission.

Dear THEMISers,

Yesterday was the 2nd launch anniversary of THEMIS. Congrats to the operations team for bringing us impeccably to this point (and not only that, but at minimal fuel, enabling ARTEMIS to become a reality). Congrats to the technical team for putting together a robust set of hardware in space and to the science team for their design and now analysis efforts that are making front page news and changing our views of how our Earth environment operates. The data being collected from the 2nd tail season are absolutely magnificent. We have several more years of data collection ahead with significant discovery potential but the data from last and next month will be analyzed for decades to come because they are trully unique.

May the quintuplets live through their 10th!


January 24, 2009: Things have been pretty quiet this week, at least in THEMIS operations land anyway. The only activity of note this week was clearing a "bad bit" in the science solid state recorder on one of the probes.

The space environment is full of gamma rays and charged particles, and every once in a great while, they will hit a memory cell in the solid state recorder and cause it to go crazy -- which results in a detectable error. Often, the spacecraft's flight software will detect the error and correct it, but very occasionally, it can only be fixed by turning off the power to the solid state recorder, letting it cool, and turning it back on. That's what we had to do for THEMIS C this week, and of course the only logical time to do it was VERY early in the morning. Fortunately, that solved the "stuck bit" problem and we're back to gathering data!

December 17 , 2008: As of Dec 15, 2008, THEMIS has entered its second tail season: the probes have started to line up in the tail. Four out of five of the THEMIS probes (satellites) have already captured the first substorm of the new season, on Dec 15, 09:15UT (precursor) and 09:40UT (onset). Four day conjunctions occur on Dec 17 and 4 days thereafter through mid-March, on 00:30 - 12:30 UT. See http://themis.ssl.berkeley.edu for details.

New predicted orbits are now available at http://sscweb.gsfc.nasa.gov.

December 16, 2008: Researchers on the THEMIS team have discovered that 20 times more solar particles can enter the Earth's magnetosphere when the solar wind's magnetic field near Earth is pointing north than when the solar wind's magnetic field is pointing south. Computer simulations show that this affect is due to the solar wind's magnetic field merging with Earth's magnetic field at two points - far above Earth's arctic and anarctic regions. This merging allows the solar wind's magnetic field to essentially become Earth's magnetic field, bringing with it the solar wind particles that flow along the solar wind's magnetic fields (these particles - plasma - are 'stuck' to magnetic fields.) This discovery leads researchers to the conclusion that when the solar wind's magnetic field in a solar storm is northward for a long time and then turns southward, there are many more particles in Earth's magnetosphere that can be energized by the southward magnetic field. This leads to large geomagnetic storms, electrical blackouts in cities and beautiful northern and southern lights (auroras.)

This newly THEMIS discovered effect is analogous to lighting a gas stove. Turning the gas on is like turning the solar wind magnetic field (IMF) northward. The gas is the solar wind plasma. And the fire to ignite the gas is the solar wind magnetic field (IMF) turning southward. If you turn on the gas on your stove just briefly and then quickly ignite the gas, the gas simply burns in a controlled fashion. This is analogous to the solar wind magnetic field turning northward just briefly and then turning southward and energizing the small amount of plasma from the solar wind in a controlled fashion (not much effect geomagnetically.) If, however, you turn on the gas on your gas stove for a long time and then ignite the gas, you can get a big explosion. This is analogous to the solar wind magnetic field turning northward and staying northward for a long time and then turning southward, energizing the huge amount of plasma very rapidly leading to a huge geomagnetic storm.

Science at NASA story can be found at http://science.nasa.gov/headlines/y2008/16dec_giantbreach.htm?list1949.

October 30, 2008: Researchers on the THEMIS team have discovered 'magnetic portals' forming high above Earth that can briefly connect our planet to the Sun. Not only are the portals common, one space physicist contends they form twice as often as anyone had previously imagined.

Full story at http://science.nasa.gov/headlines/y2008/30oct_ftes.htm?list1949.

July 24, 2008: THEMIS has determined that a substorm has been initiated 1/3 of the way to the moon's orbit in a region of magnetic reconnection. This is the first time five satellites have been aligned in just the right place and at just the right time to see the timing of events from this substorm initiation leading to the initiation of a dancing and dynamic aurora. The satellites showed how plasmas and magnetic fields moved both towards Earth and away from Earth. The bubble of plasma moving toward Earth caused a disruption in the normal electrical current much closer to Earth than the substorm initiation and then caused the auroral substorm. Learn more about this event from the NASA Press Release, "NASA Satellites Discover What Powers Northern Lights." The THEMIS media page for this press release has some excellent graphics. And you can learn more about the THEMIS mission science from the very basics on auroras and substorms on this website under Mission Science"

May 23, 2008: Despite being a rather quiet week operationally (remember: quiet is good!) we've received some excellent news from NASA headquarters. On the basis of our success so far and the high quality of science THEMIS continues to collect, NASA has agreed to extend the THEMIS mission until fiscal 2012. Part of the THEMIS proposal for the extended mission was to use remaining propellant on the two outermost probes (satellites) to send them out to the moon, and this was also provisionally accepted (pending one more technical review).

Unlike the Apollo missions of the late 60's, THEMIS does not have a big enough rocket engine to shoot the two probes directly to the moon in a matter of days. Instead, the probes will use their thrusters to slowly (over the course of many months) raise the high point of Probes 1 and 2's orbit -- currently in a 4 and 2 day long orbits respectively -- until the moon's gravity is strong enough to pull them away from earth. Even once that happens, the path to the moon is not direct. The probes will get pulled out in a large arc that eventually loops back to the moon. The whole process will take approximately a year to complete, and will be more intensive and more complicated than the maneuver planning the THEMIS mission operation center (MOC) team has ever done to date. For these two outer probes, Earth departure will be in October 2009. The MOC team already started working to improve the automation of the flight dynamics planning process to ensure we can keep up with the complexity of the maneuvers.

May 13, 2008: The THEMIS mission team received a Goddard Space Flight Center (GSFC) Group Achievement Award for the team's accomplishments.

May 12, 2008: We have been finished with the THEMIS tail season for over a month, that is when the THEMIS probes aligned within Earth's magnetotail. And now the 'Dusk Phase' season starts in order to study the radiation belts surrounding Earth. In this phase, the satellites align with one another when they pass above the 'place' where sunset (dusk) occurs for a person on Earth, hence the terminology 'Dusk Phase.' See the THEMIS science orbits page for more on this and other orbit phases.

Last week, late Wednesday night and Thursday during the day, the Mission Operations Center (MOC) team completed the last of the maneuvers which fine tune the entire THEMIS constellation so it will be ready for "day side science" this summer. In this phase, the constellation is a mirror image of the tail season alignment we had last winter. This time, the apogees (farthest point of the orbit from the earth) are in the sun direction. Instead of taking measurements inside or very near the stretched out magneto-tail, we'll be collecting science in the "bow shock" region (just imagine the wave in front of the bow of a ship). This is where the solar wind slams into the earth's magnetic field and starts to warp it back. Probe 1, which is in the most elongated orbit, can actually travel far enough away from the earth to punch through this bow shock and measure the solar wind before it has gotten a chance to be disturbed by the Earth's magnetic field.

May 8, 2008: NASA Administrator Michael Griffin bestowed upon the THEMIS team a Group Achievement Award for the successful delivery, launch and operations of the THEMIS probes.

March 5, 2008: At the all-day monthly THEMIS science meeting last week, Tuesday, many scientists came together to look at the February substorms. Although one person argued for a near-earth neutral line model (reconnection first, current disruption next, then aurora), most scientists were not ready to sign up to one interpretation of the data. As with most scientific endeavors, the answers are not as simple as one might initially hope, leading to deeper understanding of the physics and new discoveries. With multiple spacecraft available to address the question of where does the onset of substorm begin, the signatures in the particle and magnetic field data demonstrate that the magnetosphere is a very complex and dynamic system. With more than a dozen substorms collected with the THEMIS probes in just the right place and together with computer modeling of the magnetospheric system, it is clear that the upcoming analysis will lead to significant discoveries regarding substorm onsets.

The THEMIS “tail season” is now coming to an end as the THEMIS probe’s alignment with one another moves out of the magnetotail. More great science is bound to happen in the next 10 months but will not be related to the substorm onset question. More “tail season” data will be collected again, though from somewhat different vantage points, next winter.

February 17, 2008: Today is the first anniversary of THEMIS in orbit. The past year has been filled with discoveries. See the Articles Section to read about some of these discoveries, such as the first detection of a flux transfer event, when the magnetosphere combines with the solar wind in a rope-like fashion, peeling pieces of the magnetosphere off its front-side. We will provide news about some of the other science discoveries when the special THEMIS issue of the Geophysical Research Letters is published.

February 12, 2008: There were substorms throughout last week, including a substorm on Feb. 2nd, the THEMIS wedding day. See Feb. 1st news for a definition of wedding day. Due to technical difficulties, the satellite data was insufficient to tell us which model was at work for this particular substorm. Fortunately, however, there was another substorm on February 6, when the satellites were aligned with each other and close to the Sun-Earth line. The data from this day are currently being analyzed and we have high hopes that we’ll soon be getting some answers to the THEMIS substorm mystery!

To provide an idea of what a substorm look like from the all-sky imager data, here are two images (click to enlarge) showing the imager data as a mosaic across Canada and Alaska. The circles represent the field of view of the camera and the bright lines in those field of view are aurora. These images are 1 minute apart and show the substorm onset brightening right in the middle at 7:39:06 UT on Feb. 2nd. The colored dots represent how the five satellites are connected to the upper atmosphere by way of Earth's magnetic field.

February 1st, 2008: Tomorrow, Feb. 2nd, 2008, is "wedding day" for THEMIS. This is the day when all the satellites will align with each other and at the same time, the line they form will align with the magnetotail. This orbital configuration is shown in the diagram above with the perspective looking down on Earth's North Pole. So far the satellites have aligned with each other but not exactly in this line connecting the Sun and Earth, where the magnetotail blows out like a wind sock. They have lined up on the dawn side (top side of image) of the magnetosphere. And after this day, they will no longer line up directly downstream of Earth in the length of the magnetotail. They will drift to the dusk side (bottom side of the image.) For more information on the THEMIS orbits, vist the orbits page.

So, tomorrow is one of the best opportunities to really answer the question of what are the timing of the events that cause the sudden release of energy in the magnetotail and start the auroras a-dancin'! And thus, it is dubbed the "wedding day." Will a substorm happen tomorrow? We sure hope it will. Even if it doesn't, though, we still have many more chances in the coming month. Then we may finally have an answer whether this release of energy occurs in the "magnetic reconnection" region or in the "current disruption" region. Of course this will lead to all sorts of new questions, like "What is the physics in this main region that allows for the energy release?" and "How does the energy flow from one region to the other?" Some of these questions THEMIS can answer and others will have to be answered by future missions your students or children are a part of.

January 14, 2008: Two days ago, the THEMIS Electric Fields Instrument (EFI) and Mission Operations Center (MOC) team successfully rolled out, or deployed, the spin-plane Electric Fields Instrument (EFI) to their full extent (40.4 and 46.4 meters tip-to-tip) on the "spare" probe, THEMIS A (or TH-A; Probe 5, P-5). Note that the statue of liberty is 46 meters tall - so these booms really extend very far out into space. See the past two News and Events posts to learn more about this deployment. And the axial EFI booms were deployed successfully this morning. The axial booms are a bit shorter (6.7 meters tip-to-tip) and stiff since they do not have the rotation of the probes to keep them extended. All in all, this deployment took about a week and was very successful. Congratulations to the THEMIS team!

January 10, 2008: The THEMIS Electric Fields Instrument (EFI) and Mission Operations Center (MOC) team successfully rolled out, or deployed, the spin-plane Electric Fields Instrument (EFI) to 10 meters on the "spare" probe, THEMIS A (or TH-A; Probe 5, P-5). An additional 3 meters of very thin wire was also deployed that connects the preamplifier (housed in about a one inch cylinder) to the actual sensor, which is a black ball about the size of an extra-large softball. The preamplifier is used to carefully process the signal from the electric field sensor. The thicker wire connects the preamplifier with the THEMIS probe. This deployment means that the spin-plane booms are deployed a total length of 26-m tip-to-tip on both axes! To get a sense of this scale, see this 85 foot tall (26 meter tall) tree in Illinois, next to a house. See May 16th, 2007 for a diagram of the EFI booms (not-to-scale).

January 8, 2008: It's another blistery day in Berkeley, CA but the THEMIS mission operation center (MOC) team operating out of UC Berkeley communicated successfully with the "spare" probe, THEMIS A (or TH-A; Probe 5, P-5) to start to roll out, or deploy, the Electric Fields Instrument (EFI). The spin-plane EFI sensors were rolled out to 5 meters and then the spacecraft spun back up to its original spin rate. This is necessary because of angular momentum - just as a figure skater spinning stretches out her arms to slow down her spin rate, the EFI instruments as they move out will slow down the spin rate of the probe. So boosters have to be used to spin it back up again. See May 16th, 2007 for a diagram of the EFI booms deployed on a THEMIS probe.

The EFI deployment has been done on all the other probes so this is the final deployment. It will take several "satellite passes" over about a week. A satellite pass is when the satellite is in the right place to be able to send electromagnetic (or light) signals back and forth with a ground-based antenna. Luckily the strong winds didn't cause a problem with the Berkeley antenna and thus with the communication opportunities.

January 4, 2008: Happy New Year! THEMIS is officially in its "tail" season and ready to solve the mystery of substorm onset. Will we find that it starts with magnetic reconnection or current disruption? The over 30-year debate will finally be settled this coming year. Stay tuned for this exciting THEMIS science news. The mission operations center (MOC) here at the University of California at Berkeley will start ramping back up to full staffing next week. The MOC team will finish the last major hurdle: to unfurl the EFI (electric fields instrument) on THEMIS A, which has been a "spare" probe, ready to take over if any of the other four hadn't made it into their intended orbits. In the mean time, Northern California is getting hammered by a severe winter storm, and the winds here in the Berkeley hills are so high that the MOC team had to cancel all the communications passes with our antenna, and install special locking pins to keep the wind from damaging it. The rain has been coming in sideways through our entry doors! We hope you all are safe and warm during this winter season.

December 11, 2007: PR News Wire has posted the following story on THEMIS, NASA Spacecraft Make New Discoveries About Northern Lights. This story was picked by numerous science organizations and media outlets, including AOL Money & Finance, American Electronics Association, Biz Journals.com, Bolsamania (Web Financial Group), Breitbart.com, Earth Times, Forbes.com, Houston Chronicle, MySan.de and RCR Wireless News. Access the story in PDF format here (32kB).

November 21, 2007: The electric field instrument's (EFI's) booms on the outermost probe (satellite), THEMIS probe 1 (P1, or THEMIS-B, TH-B) have been completely and successfully deployed (rolled out to their extended positions). See May 16th for a diagram of the EFI booms deployed on a THEMIS probe. Congratulations to the THEMIS EFI team!

November 10-13, 2007: Early Saturday morning started with the beginning of deploying (rolling out to their extended positions), the electric field instrument's (EFI's) booms on the outermost probe (satellite), THEMIS probe 1 (P1, or THEMIS-B, TH-B). See May 16th for a diagram of the EFI booms deployed on a THEMIS probe. The deploy can only happen in a certain point in the probe's orbit. During this time, the ground antennae can only communicate with the probe when the probe's location is in an antenna's field-of-view in the sky. These times are called "passes" and indicate when the ground operations team can communicate with the probe. There were two long passes today, Nov. 13th. During these passes first the EFI and operations team deployed the EFIs to 10 meters, then the EFIs gathered data, then the probe sent the data back to Earth, and then the EFI and operations team deployed the EFIs to 18 meters. It appears that everything is going smoothly and the data looks good.

November 6, 2007: Today is Wedding Day - 88 days, the scheduled date for the completion of the mission orbit placement for Probes 1-4 (P1-P4; or THEMIS B-E, TH-B through TH-E). We did indeed complete the orbit placement for these four probes last night, performing the final orbit period adjusts on TH-B (P1) and TH-C (P2). The resulting hours when the satellites line up (conjunction hours) and the actual fuel budget are very well in line with projections.

November 2, 2007: Things have progressed like clockwork in THEMIS mission operations, both figuratively and literally. This week we successfully completed maneuvers that set the orbits of the two 1-day orbit probes exactly where we want them -- no more maneuvers on those probes until Spring 2008! The two innermost probes are, in a sense, the clock that drives the alignment of two outer probes; over the coming weeks, we just have to perform small maneuvers to adjust and tweak the outer orbits to match the "clockwork" inner orbits as precisely as we can. So the orbit placement of the four primary probes is essentially complete. The probe's orbits are essentially ready for the main science objectives. While the Earth moves around the Sun the probes' elliptical orbits remain fixed in space with respect to the stars; their farthest point (apogee) moving clockwise as viewed from the north pole relative to the Sun-Earth line. The probes spend most of their time at apogee. Thus with no further major maneuvers by January, the probes will naturally find themselves in Earth's magnetosphere approaching the anti-sunward line and be ready for tail science.

But there's still work to do! The outermost probe is now ready for us to release the wire booms of the EFI (electric fields instrument); we had to keep them stowed inside the spacecraft until after orbit placement was complete. Our plan is to finish that work up before Thanksgiving, so everyone can have a well deserved rest!

October 15 , 2007: Things continue to go like clockwork in THEMIS mission operations, and the THEMIS team is starting to see the light at the end of the orbit placement phase tunnel! As of last Friday, THEMIS probe 1 (P1, or THEMIS-B, TH-B) has been placed on its final orbit with its apogee (highest point in its orbit) at an altitude of 31 times the radius of Earth (Re). The planet’s radius is about 3,962 miles, or 6,378 kilometers. The orbit of THEMIS probe 1 (THEMIS-B) is highly elliptical and will take about 4 days to orbit Earth around Earth's equator. Placing P1 in its final orbit completes the bulk of maneuvers for P1. There will be minor tweak maneuvers continued throughout the mission. By the end of the month, we should be substantially finished with maneuvers for four of the five THEMIS probes.

Looking down (from the Northern Hemisphere) on Earth, Earth rotates counter-clockwise. Right now, both P1 (TH-B) and P2 (TH-C) are now rotating clockwise and at a slight angle (8 degrees) to the ecliptic, the plane of the Earth's orbit around the Sun. This orientation of P1 (TH-B) and P2 (TH-C) is called "ecliptic-science-south." The inner three probes, P3 (TH-D), P4 (TH-E), and P5 (TH-A), are expected to reach an "ecliptic-science-north attitude", which means that they are spinning counter-clockwise (like Earth), and will also have an 8 degree tilt to the ecliptic. The reason for this 8 degree angle is to permit good quality electric field instrument measurements. By the end of the month, THEMIS should be substantially finished with maneuvers for four of the five THEMIS probes.

September 28, 2007: The last week's worth of activities have gone very well for THEMIS. The large maneuver on Probe 1 (the outermost probe) increased the orbit to more than 53 hours. We're now getting used to the fact that this probe will swing by close to earth less and less frequently as we increase its orbital period.

Today will be the THEMIS satellite's most intense set of activities yet. In just the next 30 hours, we will have performed various kinds of maneuvers on four different probes, using seven separate thruster firing activities (some probes need a sequence of thruster firings). And on top of that, we'll re-pressurize the fuel tank on the last of the five probes, giving it more kick for its upcoming maneuvers.

September 21, 2007: Today, the THEMIS Mission Operations Team is planning a maneuver for P1 (the probe that that will be in the outermost orbit of the THEMIS constellation). This will be a biggie -- in one maneuver, they change the orbit period from 36 hours to 54 hours! When they're all done, the P1 orbit period will be 96 hours, so still more maneuvers will be required. All the probes are in an excellent state of health, and as minor anomalies change the schedule, they've adapted, re-planned, and continued on.

September 17, 2007: The THEMIS mission operations team has successfully performed the fist axial burn raising the apogee, the farthest point of the orbit, of probe 1 (P1) from 14.6 Earth Radii (Re) to 16Re. 1 Earth Radius = 6,378 km (3963 miles). The team is proceeding with orbit placement of all probes towards their final positions to be completed by mid-December 2007.

August 10, 2007: Everything is working well on THEMIS. Three of the Electric Field Instruments (EFIs) have been completely deployed. It took 68 thrust maneuvers to get to this point! These thrust maneuvers lead to adjusted orbits and change in the probes' (satellites') attitudes (orientations) and spin rates. THEMIS is still in its coast phase until the end of this month. Then the THEMIS flight operation team will begin to send commands to the probes for many more thrust maneuvers in order to put the probes into their prime-mission orbits. The final maneuvers will happen in December. The probes now have both numbers and letters associated with them. Here is the letter-number scheme: 5 (A), 4 (E), 3 (D), 2 (C), 1 (B); Probes 1 (B) and 5 (A) (closest and farthest out) have the most maneuvers needed to place them in orbit, so the EFIs were not deployed for those two probes.

August 8, 2007: The first science team meeting after the launch of THEMIS has concluded. Scientists examined data from the first substorm observed by THEMIS. They shared their interpretations of how the boundary between the solar wind and Earth's magnetosphere expanded and evolved. They also discussed observations of cold, dense plasma inside the magnetosphere near this boundary.

August 6, 2007: The first science team meeting after the launch of THEMIS is occurring at the University of California, Berkeley. Scientists are sharing their first looks at the data coming back from the five satellites as they travel in and out of Earth's Magnetosphere, crossing the boundary between the solar wind and the magnetosphere.

July 30, 2007: The First THEMIS Science Working Team Meeting will be held on August 6-8, 2007 at the UC Berkeley Space Sciences Laboratory. The agenda is available as a Acrobat Reader PDF file here. Please find directions to the lab and list of accommodations at: http://ssl.berkeley.edu

July 28, 2007: THEMIS is in the news in France. Practice your French and check out the broadcast produced by Laurianne Geffroy, which used footage provided by UC Berkeley.

July 27, 2007: The THEMIS constellation of five probes (satellites) is in the middle of its final adjustments to the scientific data collection. On all probes, data is now being compressed, similar to the way files are made smaller in a "zip" compression on your computer. This allows more data to get to the ground. The Electric Fields Instrument (EFI) has been reconfigured to optimize its performance. See below for more information on the EFI. The THEMIS science team are making final changes to flight software, the computer software on the probes. These changes relate to a mode of operating the particle instruments that allow the scientist to keep the highest resolution of particle data (known as "Particle Burst" data). These changes also allow the on-board probe software (flight software) to calculate the velocity, pressure, and other such quantities, which is another way of compressing the particle data. These changes will permit captures of scientifically important boundaries at high time resolution and result in further increase in the data quality of the transmitted data.

July 1, 2007: The dayside THEMIS science officially starts today. We are looking forward to the many discoveries THEMIS will make during this phase of its mission!

June 7 , 2007: As of today, all the booms and sensors on the electric field instrument (EFI) have been deployed (rolled out to their extended positions) on probe D and E. Congratulations to the EFI and operations team (who send all the commands to the probes)! See May 16th news for an the image of a THEMIS probe with the booms deployed.

June 1 , 2007: The 10 meter thin wire booms and sensors on the electric field instrument (EFI) have been deployed (rolled out to their extended positions) on probe D and are being deployed now on probe E. See May 16th news for an the image of a THEMIS probe with the booms deployed.

May 30, 2007: The wire booms and sensors on the electric field instrument (EFI) will be deployed (rolled out to their extended positions) on probes D and E starting tomorrow, Thursday, May 30th. This takes many days because as the booms go out they could potentially disturbing the probe's configuration and motion. The plan is to do part of the deployment Thursday and Friday, then take two days break, then finish on Monday and Tuesday, June 4th and 5th. The axial boom will be deployed on Thursday, June 7th. See May 16th news for an the image of a THEMIS probe with the booms deployed.

May 17, 2007: The News Hour with Jim Lehrer on PBS aired a segment called "Space Storms - High school students and teachers are helping collect data for NASA's THEMIS mission to study space storms" last night. The audio and other supplemental information can be heard and read on the PBS website. The video is available by going to the News Hour video archive page and submitting a search for THEMIS

May 16, 2007: The wire booms and sensors on the electric field instrument (EFI) have been successfully deployed (rolled out to their extended positions) on probe C. The ensuing data proved it was a cause for celebration. Drs. John Bonnell and Forrest Mozer, the Leads on the EFI, were both extremely happy with the instrument behavior. The booms have deployed to the final 20&25m length. All indications are that THEMIS C has now two good, fully deployed EFI spin plane boom pairs. Congratulations to the EFI team for pulling it off!

The EFI axial's will be deployed on probe C by end of this week assuming the spinning of the spacecraft is stable. In the second week in June, after some additional orbit nudges using the thrusters, the THEMIS team will begin to deploy the EFIs on probes D and E.

May 10, 2007: The wire booms and sensors on the electric field instrument (EFI) on probe C are being deployed (rolled out to their extended positions) today. Yesterday the doors were opened to allow this process to occur. There will be more updates on this deployment soon.

May 2, 2007: A recent NASA news release includes an image showing Io's auroras. The news release also explains some of dynamics of the auroras. Please visit the Non-Earth Auroras section of the THEMIS website for more information.

May 1, 2007: The THEMIS probes are in their elliptical coast phase orbits with the apogee, the highest point of the orbit, on the dusk side of Earth. To see the upcoming orbits, visit the THEMIS science orbits page. All instruments on the probes are taking data, though the electric field instrument (EFI) still needs to have its booms out. This will start on May 9, on probe THEMIS C. During the week prior to EFI deployment the science team will be collecting science orbits similar to the nominal science. The team is ironing out small compatibility issues that are noticed during this phase, calibrating the instruments, while also testing different ways of collecting data (operational modes). The EFI deployment on probe THEMIS C will be completed in 2 weeks, and will be followed by similar deployments on probes B and D.

April 12th, 2007: Thanks to the unique capability of Cluster to perform simultaneous multipoint measurements, they were able to derive several physical parameters never estimated before for region in which flows in Earth's magnetosphere reverses direction. The data is consistent with turbulence, one way for the current disruption to occur in Earth's magnetotail. THEMIS' ability to make multipoint measurements aligned in Earth's magnetotail out from the current disruption region to the magnetic reconnection region will be able to tie these types of Cluster observations with the entire series of events during a substorm. To read more about the Cluster research, visit the European Space Agency's website article from our articles section.

April 9th, 2007: The THEMIS probes are now in their expected elliptical orbit configuration for the coast phase. This configuration is as follows: <------B--------C-E-D--------A-----, that is that probe B will lead with probes C, E, and D following as a "e;pack"e; with approximately 100 km separation between them and probe A lagging behind. The distance between probes B and A are around 5-10,000 km. Minor adjustments on the orbits of the probes are still to be completed before scientist can start to use the data from the dayside of the magnetosphere to do science. There was a special orbit on Sunday (April 8th) to collect magnetic and electric field data. This data will be checked out this week. Next week the THEMIS team will send out (deploy) the booms (long poles and wires) of the Electric Field Instrument (EFI). See the March 15th news for more information on the EFIs.

March 15th, 2007: By the end of the day yesterday, THEMIS had achieved a major milestone. All instruments on all five probes are now on and collecting data. The electric field instrument (EFI) booms have yet to be deployed but we expect deployments to begin in the not-too-distant future. The EFI will measure electric fields in space. In order to do this, the sensor is put at the end of wires or poles (booms) which are extended out away from the spacecraft when they are deployed. The sensor needs to be far from the spacecraft because there are electric fields around the spacecraft due to the interaction of the spacecraft with the charged particles space as well as with sunlight.

March 14th, 2007: In the past day, THEMIS testing showed us that the probes can telemeter at 64 K bits per second to Berkeley throughout the current probes' orbits. Probe C and D solid state telescopes (SSTs) were turned on again and left running in order to get a measurement without the electrostatic analyzer (ESA) interference. See March 8th for more information about the SST. The SST on probe E was reconfigured. At the present time the high voltage (HV) on probe A's and B's ESAs are running (see March 7th for more information about the ESA instrument). SST is up and running on C and D. Science data is being collected and returned successfully in "Slow Survey mode," a mode meant to provide course data over most of an orbit as opposed to "Fast Survey mode," meant to sample the magnetosphere at a higher data rate. Assuming the data looks good overnight, the team will raise ESA High Voltage on C, D and E while turning on SST A, B and E. Once this is done, this will complete the initial commissioning on all instruments.

March 12th, 2007: Today, the electrostatic analyzer (ESA) electron High Voltages were checked out on probes A, B, D and E. All four performed beautifully (see March 7th for more information about the ESA instrument). The ESA probe C was not checked out because of an ongoing set-up issue with the ESA/SST controller.

March 11th, 2007: Today, the solid state telescope (SST) on Probe C was powered up again in order to check out the sun-blanking circuitry. Currents looked good and stable, but the expected packet telemetry was not coming through. Once again, SST was turned off while engineers worked on an updated plan for SST.

March 10th, 2007: Today, ESA ion High Voltages were checked out on all five probes. Each was ramped up successfully to full voltage and all five performed perfectly (see March 7th for more information about the ESA instrument). The ESA on Probe A was intentionally left at high voltage while the other probe ESAs were set at low voltages for the time being. The science team reports nominal performance from all five ESAs, and excellent science data quality from the ion detector on Probe A.

March 8th, 2007: Today, the Solid State Telescopes, SSTs, on Probes B and C were turned on. The SST will measure the flux of the high energy charged particles, electrons and ions, in space. Probe D’s SST was not turned on because the Solid State Recorder (SSR) was full. The SSR is a memory inside the Instrument Data Processing Unit (IDPU), which holds all the instrument data prior to transmission. It was full because it was holding all the electrostatic analyzer (ESA) data from yesterday's testing. Probe A and E's SSTs were turned on, but they were turned off before the end of their contacts. The SST's had to be turned off due to sunlight in their apertures (openings) at these attitudes (satellite orientation relative to the Earth's orbit plane around the Sun, ecliptic), which made their electrical currents too high. By the end of the day, all SSTs were powered off in order to allow maneuvers to proceed.

Probes A, E, D and B were maneuvered such that they align north-south with respect to the ecliptic . This enables better communications, stable power and thermal conditions. Fuel usage since launch has been a mere 0.2 kg. Science and engineering data for all probes was telemetered to the ground. Science data is the samples from the instruments. Science data is stored inside the IDPU in the SSR memory. Engineering data includes temperatures, voltages and currents of the boxes on the spacecraft. All probes remain in good health and their orbits are well known.

March 7th, 2007: Today, all the electrostatic analyzer (ESA) contamination covers were successfully opened. The ESA will measure the flux of charged particles, electrons and ions, in space. These covers were used to protect the sensitive particle detectors inside the ESA sensors until they are safely in the clean vacuum of space. Each ESA's detector electronics circuitry is tested in flight using an internal test pulser, an electronic device that stimulates the the electrical response of the detector and the electronic circuits in the Instrument Data Processing Unit (IDPU). The IDPU is essentially the brain of the instruments. All ESAs performed well in this test. Later this week, the ESA's high voltage needed to operate the charged particle detectors will be turned.

March 5th, 2007: Today, the THEMIS team aborted the planned maneuvers on Probes A, D and E (see March 4th news) because the communication with the probes was not clear enough. We are re-planning these maneuvers for later in the week.

March 4th, 2007: All five probes remain in excellent health. Over the weekend, Probes B and C were maneuvered so that their antennae would align north-south with respect to the ecliptic (Earth's orbit plane around the Sun). While both maneuvers were successful in general, Probe B's maneuver on Saturday resulted in a side tilt of 40+ degrees to the ecliptic. Probes A, D and E will be maneuvered to align north-south with respect to the ecliptic in the early morning of March 6th and, assuming those maneuvers go well, Probe B will be tipped up on March 7.

February 27th, 2007: All the probes have now been spun up to 20 Rotations Per Minute (RPM) and are still taking magnetic field data. The next planned maneuvers will rotate the satellites so that their spin-axis is North-South to the Earth's orbit plane about the Sun. This will be performed in steps, where Probes B & C will maneuver on Friday and Probes D, A & E will maneuver on Saturday. This allows science data to be recovered in an unusual mixed configuration since three probes will be "sideways" to the other two.

February 26th, 2007: The Mission Operations (MO) team released the magnetometer booms (long poles holding the magnetometers) on all five probes. These booms were launched folded on top of the probes and had to be released to their extended position for the magnetometers to be far enough away from the magnetic fields on the probes. After this deployment, both probes and instrument data look nominal with the Fluxgate, Search Coil, Electric Field and ESA Low Voltage on. All probes are taking magnetic data in preparation for a maneuver to ecliptic normal attitude at the end of the week.

February 24th, 2007: The THEMIS team has accomplished an amazing amount in the last 24 on the five probes. All five Electric Field Instruments (EFI) and Search Coil Magnetometers (SCM) were turned on, a calibration of Probe B Flux-Gate Magnetometer (FGM) was performed, and all probes were spun down to 11 Rotations Per Minute (RPM). The mission operations (MO) team recovered all engineering and science data from all probes, too.

As the probes have begun to separate a little, the MO team was also able to contact three probes simultaneously using three different ground stations. Probes E, D and C communicated with Berkeley, Santiago and Wallops. All five probes remain in excellent health. Probe temperatures are now very mild because of their new attitude (the way they are aligned with respect to the Sun-Earth system). The probes' attitude is now such that the Sun's light shines on their side panels instead of on the tops of the probes, which was causing the probes to overheat.

February 23rd, 2007: Today, on probes C and B the Electric Fields Instrument (EFI) and the Search Coil Magnetometer (SCM) instruments were turned on. The team calibrated the Flux-Gate Magnetometer (FGM) on probe B. The first THEMIS instrument data for EFI and SCM were played out and looked nominal.

The THEMIS team slowed the rotation of all five probes from 16-17 rotations per minute to 11 rotations per minute. This was done so the magnetometer boom can be deployed without problems. To change the rotation rate, the radial thrusters were fired. As we expected, each spacecraft wobbled a bit, but telemetry and commanding were unaffected.

All five probes remain in excellent health. Temperatures are very mild on the probes now in their nominal attitude with sun on their side panels.

February 22nd, 2007: Today, on all probes, the Instrument Data Processors, Fluxgate Magnetometers (FGM), and Electrostatic Analyzers' Low Voltage Power Supplies were turned on and checked out. All systems were nominal in current and temperature. FGM sensor data recording began and we should see the first science data play out in the next orbit.

All five probes are in very good health. Communications with the probes have improved greatly due to better orbit and attitude information.

Probe A was rolled so that the sun is on its side-panels rather than on its top. This will cool the top down.

February 21th, 2007: Today, THEMIS Probes B, C, D and E were successfully maneuvered 33 degrees as planned to have sun on their side solar arrays. Each maneuver took about 2.5 minutes while each probe fired 40 pulses on one of the axial thrusters in phase with the spin. This attitude provides better temperatures around the probes as well as better communication to the ground. By plan, Probe A was left in the launch attitude for one half orbit until we contact it one more time with TDRS. After that time, Probe A will be rolled to the same attitude as the other four.

All five probes are in very good health, but the team is currently working two technical items at this time. One difficulty is that the batteries are getting too much power from the solar arrays and this causes some glitches in the circuits, which are trying to keep the power from being too high. Another difficulty is regarding the command and telemetry link performance of probes B and C, which have some dips in their signal. This may be due to the un-deployed magnetometer booms on the top of the spacecraft and may go away when we deploy them Sunday 2/25/07.

February 20th, 2007: Over the past 2 days the THEMIS probes experienced signal degradation to the point that three scheduled contacts with the probes failed. After recalculating the orbits of the probes, the ground stations found the probes with good signal strength. The probes were never in any real danger - they were just on a slightly different orbit than originally calculated. This injection orbit is indeed quite stable and the probe state of health is nominal.

February 19th, 2007: A digital display story has been created and published for the ViewSpace network to share the wonders of the aurora and the excitement of the THEMIS mission with patrons at museums and science centers that subscribe to the ViewSpace network. To find out how you can set up a ViewSpace show at your own science center or museum, visit the Space Telescope Science Institute's ViewSpace webpage.

February 18th, 2007: THEMIS successfully launched on Saturday, February 17th at 6:01pm ET. The probes released approximately an hour later. The UC Berkeley ground station had first contact with the probes around this time. All five were commanded briefly and all five responded with return signals. Their trajectories were right on target.

NASA had a press release about the launch linked from the NASA THEMIS website.

Here is a detailed report about contact with the five probes from the Berkeley Mission Operations Center:

At 4:11pm Pacific, the transmitter on Probe A was commanded on successfully by the Berkeley Mission Operations Center (MOC) and telemetry received, all via the NASA Tracking and Data Relay Satellite (TDRS). All of the probes were still attached to the Probe Carrier Assembly (PCA) at that point. Separation from the PCA was observed via probe A telemetry at approximately 04:14pm pacific, with nominal spin rate and sun angle observed on probe A. Probe A transmitter was commanded off by the Berkeley MOC at 4:17 pacific.

The Berkeley Ground Station (BGS) performed a round robin checkout of all 5 probes beginning at approximately 04:23pm pacific with probe B. The transmitter for each probe was commanded on and the acquisition of state of health telemetry was attempted. Telemetry locked intermittently on B because the signal strength was weak due to the angle between the probe antenna and the ground antenna (ground antenna was looking at the bottom of the probe). This was the case for C, D, E, and A. However, the transmitter on each probe was

February 16th, 2007: THEMIS launch postponed for 24 hours. Read about today's launch attempt at NASA's THEMIS launch blog.

February 15th, 2007: View the THEMIS L-1 News Conference that will be broadcast live on NASA TV from 3-5pm ET. Panelists will include Frank Snow, Vassilis, Dave Sibeck and Peter Harvey.

February 14th, 2007:

Launch Update
There was lightning at Cape Canaveral late yesterday that stopped the fueling of the THEMIS Delta II rocket. This caused a one-day delay in the launch but luckily no lightning came close to the launch pad. Today the team completed the oxidixer and fuel loading.

Thursday February 15th plans
8:00-12:00pm (ET) - Final pre-launch test of the satellites
9:00am (ET) - Launch Readiness Review
Friday February 16th plans
11:00am (ET) - Begin L-7 countdown procedure at blockhouse
2:00pm (ET) - Management on console
6:05pm (ET) - LIFTOFF !

February 13th, 2007: The THEMIS scientists take a tour near the launch pad at Cape Canaveral, FL to see THEMIS on the pad almost ready for launch. The photographs shows an image of what they saw, taken by Harald Frey.

February 8th, 2007: At 5 AM this morning, the THEMIS engineers performed a final removal of red tag items, performed a final visual inspection and said goodbye to the five spacecraft they've nurtured for the past year. After taking a few photos, the fairing was successfully installed. Final electrical tests and launch simulations are scheduled for the next few days. The project remains on track for a Feb 15 launch.

February 5th, 2007: The team executed the Launch Countdown procedure including battery charge of all spacecraft. In this procedure they did everything they will do on launch day ... minus the actual launch! It was not so easy to get there due to a variety of hurdles along the way including partially demated launch tower connector and voice communications which seemed to randomly go up and down plus failed regular Internet service. With the support of various people all these complications were overcome and the test completed. Battery charging went very nicely as did the switch over to internal battery power at launch minus 10 minutes.

February 3rd, 2007: The THEMIS probe carrier assembly was transported to the pad early this morning. The attached photo shows the PCA in its transport cannister. Launch site processing and mission operations simulations are continuing nominally, although a lightning alert delayed activities on the pad mid-day today. While we may have to defer first electrical tests until early tomorrow morning, we are still on track for a Feb 15 launch. You can watch the activities live on the Kennedy Space Center website.

January 31th, 2007: The THEMIS website at the French Space Agency (Centre national d’études spatiales, CNES) is up and available. An article (in French) about THEMIS is also available on-line. Both are linked in the articles section.

January 29th, 2007: Today the THEMIS spacecraft will be mated to the 3rd stage of the rocket. You can get video of this by clicking on the link "AE Video 1 Streaming Feed" at the following URL: http://countdown.ksc.nasa.gov/elv/.

January 26th, 2007: THEMIS will be launched from the same Pad as STEREO. Jetty Park is 2.9 miles from the pad and is apparently closer than the official site. Visit this website for information about launch viewing: Where & How to Watch Delta 2 Launches.

January 24th, 2007: THEMIS passed its Mission Readiness Board review yesterday. The NASA Associate Administrator for the Science Mission Directorate, Mary Cleave, stated that the mission is a pathfinder for future Heliospheric constellations and thanked the team for its efforts in making it possible for the entire community. Deputy AA Colleen Hartman stated that this is a scientifically very exciting mission and that she felt really fortunate to see it through end-to-end in her term. Dick Fisher, Heliophysics Division director, stated that the team performance in general and in this review in particular, sets a very high standard for missions to come.

January 17th, 2007: Today will be the THEMIS media day - 30 days prior to launch. Come find out about the THEMIS launch at the University of California Berkeley's Space Sciences Laboratory or at NASA's Goddard Space Flight Center. Find out more at the NASA press release about this media event.

January 12th, 2007: Solid rocket boosters are added to the base of the United Space Alliance Delta II rocket. A total of nine will assist in the launch of the THEMIS integrated spacecraft. See photographs on the Kennedy Space Station Media Gallery as well as the NASA press release.

January 5th, 2007: The THEMIS Mission Readiness Review went very well. We were given the Green Light to proceed. And this morning, the first stage of the rocket was erected on the pad. The five THEMIS probes are now in the hazardous payload building at Astrotech. All fueling is complete. Next week they will be integrated to the Probe Carrier. You can see them live on the Kennedy Space Station NASA site.

January 3rd, 2007: Today's meeting at the Huntington Beach facility reviewed and approved the THEMIS Delta II launch vehicle to be assembled on PAD 17B at CCAFS. The booster will be erected starting Saturday morning at 5am EST.

December 11, 2006: With the decision to ship the Probes and Carrier to Florida, the THEMIS team members packed up the probes at JPL, said "good bye" to their friends there and hit the road. Paul Turin, Greg Dalton, Daniele Meilhan and Michael Ludlam piled in the lead van and kept the two vans company across country. Arriving this morning, the probes and GSE were off-loaded and set up in the Astrotech facility. The photographs show the probes in their new home. (Note one was unbagged so NASA photographers could get a look, but we rebagged it right afterward.) See the press release in the articles section.

December 7, 2006: The THEMIS probes are in the process of being moved from California to Florida where they will be launched into orbit in February. So far they have been packed up for shipment to Kennedy Space Center (KSC). The THEMIS team will soon move the Probe Carrier stored in upper Jet Propulsion Laboratory (JPL) to the Spacecraft Assembly Facility (SAF) airlock. The THEMIS team will also organize the equipment going to KSC in the SAF cleanroom. These activities will streamline the loading of the trucks early Friday morning, Dec 8th.

December 6, 2006: The November 29th meeting at Kennedy Space Center concluded with a unanimous "Go!" given to transport the payload from JPL to Florida for launch processing. THEMIS continues onward toward a February 15th launch at 6:07 pm eastern.

October 19, 2006: THEMIS probes are getting ready to be shipped from their storage place at JPL to the launch site.

September 20, 2006: THEMIS FACT SHEET: THEMIS Mission to Determine the Cause of Disturbances in Geospace.

September 18, 2006: Legion Magazine released a new article about THEMIS called Capturing The Light Fantastic. You can also view the article as JPEG: 1, 2, 3, 4, 5, 6.

August 9, 2006: A national conference for science educators at the Canadian Space Agency in Montreal. Dr. Eric Donovan, Canadian THEMIS Co-I is a keynote speaker to talk about THEMIS and Aurora Borealis.

August 4, 2006: Article about THEMIS on the Canadian Space Agency website: THEMIS: The Stakeout for Northern Lights in the Canadian Tundra.

July 24, 2006: Two new Austrian press articles for THEMIS from Austrian Space Academy and Austrian press Agency :

July 18, 2006: THEMIS Probes' Z-Axis Vibration test in the 3rd week of the environmental test at JPL: The probe carrier assembly (PCA) is hoisted onto the vibration table. Then, the PCA is fastened to the table, where the PCA is in the vibration test.

July 17, 2006: New pictures of THEMIS probes from the 2nd week of the environmental test at JPL: The probes were moved to the probe carrier one by one until the probe carrier has all four probes. The fifth probe is then attached to the top of the probe carrier assembly. Probe carrier assembly has the Solar Array Covers on. The probe carrier assembly with covers removed is ready for the vibration test, which is then conducted. Lastly, the probe carrier assembly is then moved to the Dolly.

July 13, 2006: Environmental test at JPL is in progress and all is going well. This image shows all five probes on the probe carrier without the covers.

July 10, 2006: THEMIS probes at JPL are ready for the environmental testing. See the side view and top view of the probes.

June 28, 2006: Three of the THEMIS spacecraft were packed up and transported over night to JPL. Please go to Gallery to view pictures.

June 20, 2006: A virtual tour of the integration room with five spacecraft.

June 19, 2006: The fifth spacecraft/probe arrived from Swales to UCB last Thursday and since then was checked out by itself and as side-by-side with the pre-integrated fifth instrument suite. Environmental Testing at JPL, starting June 29, and Launch Site processing in Florida, is starting in mid-August. A collage of the five spacecrafts is shown in this picture all in one room at SSL.

June 8, 2006: In March and April, the THEMIS probe, F2, was the first probe to be tested at the Jet Propulsion Laboratory (JPL) in Pasadena, CA with all it's instruments and solar panels in tact. Check out the slide show describing this process.

May 30, 2006: Today, the fourth THEMIS probe, out of five, has been delivered to the University of California at Berkeley (UCB). This probe is labeled F1. Now all four probes, F1 through F4, are at UCB where they are in different stages of integration and testing.

May 19, 2006: Three out of the five THEMIS probes are now at the University of California at Berkeley (UCB). They reside in a clean room where tests are performed just about every day. Scientists are anxiously looking at the results and making sure that their instruments will perform in a satisfactory manner. Quality Assurance personnel keep a close eye on the every move of the spacecrafts. Managers keep monitoring the schedule and the budget as launch is only months away now. Engineers test, correct and improve every tiny detail that needs attention. And technicians install, wrap, and connect hardware.

April 24, 2006: THEMIS reached an important milestone, with the first of our probes having finished environmental testing and passing with flying colors.

March 19, 2006: The THEMIS project hit a milestone this week. The lab bustled with activity as engineers and technicians packed up the first probe (satellite) to go to Pasadena at the Jet Propulsion Laboratory for environmental testing. These tests are magnetic tests, thermal vacuum tests, vibration tests, alignments tests, shock test, and acoustic test. Tons of ground support equipment, computers, and documentation were packaged as well as the probe. A freight truck transported all this during the night between Berkeley and Southern California with two THEMIS engineers in a pilot car. Some of UC Berkeley Engineers will end up spending weeks away from home. Our lab will remain busy as the second and third probes are about to be delivered to have their instruments tested.

Dec, 2005: The flight magnetometer booms were successfully installed on the first spacecraft (officially called probe 2). Here you can see an image of engineer Greg Dalton next to the extended magnetometer booms. Magnetometers are instruments that measure magnetic fields and they need to be placed far from the spacecraft because the electrical currents to operate the experiments create a magnetic field. This spacecraft magnetic field can disrupt the magnetometer measurements of Earth's magnetosphere if it is too close to the instrument.

Nov 28, 2005: The first spacecraft bus, i.e. the body of the spacecraft, has arrived at the University of California, Berkeley from Swales! The instruments will be integrated with the spacecraft bus and then tested further compatibility issues.

July 18, 2005: Thank you note to THEMIS PI and Scientists from U.S. Consulate General, Vancouver Canada:

Drs. Angelopoulos, Mende, Russell and Donovan,

On behalf of the U.S. mission in Canada, I would like to thank all of you for participating in today's digital video conference on the THEMIS Project. Your presentations were fascinating, insightful and well-received. We have already heard from program participants in Whitehorse, Yellowknife, and Iqualuit that they thoroughly enjoyed all aspects of the program. Many expressed a keen interest in learning more as the project proceeds, and some might be contacting you soon to suggest new sites for ground observatories. In addition, educators in our groups discussed ways they can incorporate the study of the aurora borealis into their science curriculum, drawing from your websites. We greatly appreciate your help in making this happen.

This was an experiment for us as we connected via videolink for the first time with Canada's North. We have some minor glitches to work out, but I think that overall, things went very well. Thanks for your patience through the whole process. Thank you also for working with us to share your excellent example of Canadian-U.S. cooperation with residents of the North.

Best Regards,

Ian T. Hillman
Public Affairs Officer
U.S. Consulate General Vancouver.
Vancouver, B.C. V6E 2M6

January 17, 2005: The electric fields instrument will be located on a long pole (boom) once the THEMIS satellites are in space. This boom starts as a coil of metal and springs out once the satellite is in space orbiting Earth. It is important to test how this coiled metal springs out to its 10 feet (3 meter) length in very cold and very hot temperatures that the satellite and instrument will encounter in space. See movies of the recent test in very hot temperatures and an explanation of the test by space physicist, Dr. John Bonnell.

October 14, 2004: A magnetometer was installed outside the elementary school near the Red Cloud High School in Pine Ridge, SD. An article about this installation can be found here.

October 12, 2004: A magnetometer was installed at the Hot Springs High School in Hot Springs, MT

October 4-5, 2004: Magnetometer is installed at the Petersburg City Schools in Petersburg, AK with science teacher Vic Trautman.

August 27, 2004: Magnetometer is installed at the Western Nevada Community College observatory in Carson City, NV with Professor Robert Collier, Assistant Gerald Brandvold, and Carson Middle School science teacher, Terry Parent.

June, 2004: The THEMIS project passed its Critical Design Review (CDR) and engineers are now building instruments and the spacecraft contractor, Swales, is beginning to build the first spacecraft bus, e.g. body of the spacecraft where the instruments are located.

April 14, 2004: The first ground-based observatory with an all-sky imager and its enclosure is successfully operating in Athabasca in Canada. It has a heater and an air-conditioner in order to keep the camera at the right temperature in the arctic environment.

November 14, 2003: THEMIS has passed its Preliminary Design Review! This means that the mission is on schedule, allowing us to begin lesson plans, select schools for our GEONS project, and allowing engineers to begin building instruments.

March 20, 2003: A new NASA mission has been selected to solve the mystery of what triggers brilliant and rapidly moving auroral forms to erupt from a slowly moving single auroral band across the sky. The NASA Mission, "Time History of Events and Macroscale Interactions during Substorms (THEMIS)" will send five satellites to space, twenty cameras to Canada and Alaska, and thirty magnetometers over the Northern U.S. and Canada in order to solve this mystery.