I got some grief for calling the GOCE spacecraft ‘sexy’ last year, but I’m sticking with that description. What a gorgeous spacecraft! And the GOCE team has stuck with their spacecraft while it had to stand down from launch in September of 2008 when problems were discovered with the guidance and navigation subsystems on the Russian Breeze KM rocket. GOCE had to be de-mated from the rocket and brought back into the clean room last year, but now is back on the launch pad, and is scheduled to liftoff on Monday, March 16 at 14:21 GMT from the Plesetsk Cosmodrome in northern Russia.
GOCE, which stands for Gravity field and steady-state Ocean Circulation Explorer will investigate and map Earth’s gravitational field. It will also provide a high-resolution map of Earth’s geoid, which is the surface of equal gravitational potential defined by the gravity field. This will greatly improve our knowledge and understanding of the Earth’s internal structure, and will be used as a much-improved reference for ocean and climate studies, including sea-level changes, oceanic circulation and ice caps dynamics survey. Numerous applications are expected in climatology, oceanography and geophysics. GOCE at the launchpad in Russia. Credit: ESA
The 1 ton, 5 meter-long spacecraft will be in an extra low orbit (260 km, or 161 miles) and will experience drag from Earth’s upper atmosphere, so its smooth and lean (and sexy) surface helps reduce the friction. Adding to the sleek design is that the solar panels are attached to the long body of the satellite instead of sticking out and adding to the drag. However, the spacecraft will need a boost to its orbit occasionally, and has state of the art ion engines.
Artists image of Odyssey in orbit around Mars. Credit: NASA/JPL
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NASA’s Mars Odyssey orbiter was successfully rebooted today, to thwart any potential future problems with memory corruption of its main systems, and with hopes of restoring use of back-up systems. Odyssey has been functioning normally, but its memory cache hadn’t been cleared for five years. The spacecraft followed commands to shut down and then restart, a strategy that engineers hoped would clear any memory flaws. The procedure also restored Odyssey’s onboard set of backup systems, called the spacecraft’s “B side,” allowing its use in the future when necessary. “For nearly two years, we have not known for certain whether the backup systems would be usable, so this successful reboot has allowed us to ascertain their health and availability for future use,” said Odyssey Project Manager Philip Varghese of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
Engineers were going to perform the reboot on March 10, but an unexpected rise in temperature of the star camera in Odyssey’s navigation system prompted a postponement of the procedure. Engineers identified the cause as a heater circuit that was temporarily stuck “on.” The circuit was turned off before today’s reboot.
Memory corruption is caused by cosmic ray hits and other effects of the space radiation environment. This reboot was not a risk-free event, but the Odyssey team and NASA carefully weighed the risks of performing a cold reboot compared with the risk of doing nothing, and determined that the best thing was to reboot now instead of waiting for potential problems to crop up.
Odyssey, which also serves as a relay for communications for the Mars Exploration Rovers, has been orbiting Mars since 2001. Odyssey has never switched from its primary set of components, the “A side,” to the backup set, which includes an identical computer processor, navigation sensors, relay radio and other components. In March 2006, the B-side spare of a component for managing the distribution of power became inoperable. Analysis by engineers identified a possibility that rebooting Odyssey might restore that component, but it had not been done until today. And now the B-side seems to be working.
The Odyssey team began a series of steps after the reboot to carefully return the spacecraft to full functioning over the next few days. Odyssey and all the science instruments should be back to studying Mars by next week.
Kepler as it appeared moments prior to launch in Florida. Credit: NASA
NASA’s Kepler mission lifted off without a hitch just before 11 p.m. local time Friday from Cape Canaveral Air Force Station in Florida.
The launch was a bit of a nail-biter, coming on the heels of last week’s failure of the Orbiting Carbon Observatory, which plummeted into the ocean when its fairing malfunctioned. But everything for the Kepler launch — from the weather to the countdown — went flawlessly. At five minutes to launch, Kepler’s rockets sent ribbons of smoke into Florida’s 65-degree Fahrenheit (18-degree Celsius) nighttime air under perfectly clear skies. With 30 seconds left, confirmation commands were exchanged with practiced precision. The casing (called the fairing) fell off with grace, and three minutes into the flight, the craft was cruising away from Earth at nearly 7,000 miles (11,265 kilometers) per hour. Each launch event happened within three seconds of its predicted time.
Kepler’s engines shut down at 11:45 p.m. U.S. eastern time, and the craft achieved separation just before midnight, about 62 minutes after launch. Now, for the next three and a half years, Kepler will trail Earth in orbit and stare at a single patch of sky in the Cygnus-Lyra region of the Milky Way.
Kepler fires the imagination, as it could finally address the age-old question of whether we Earthlings are alone. William Borucki, NASA’s principal investigator for Kepler science, spoke about the mission at a recent NASA press conference and said if Kepler spies Earth-like planets in the habitable zones of other stars, “life may well be common throughout our universe. If on the other hand we don’t find any, that will be another profound discovery. In fact it will mean there will be no Star Trek.”
The $500 million Kepler mission will spend three and a half years surveying more than 100,000 sun-like stars in Cygnus-Lyra. Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by.
By staring at one large patch of sky for the duration of its lifetime, Kepler will be able to watch planets periodically transit their stars over multiple cycles, allowing astronomers to confirm the presence of planets and use the Hubble and Spitzer space telescopes, along with ground-based telescopes, to characterize their atmospheres and orbits. Earth-size planets in habitable zones would theoretically take about a year to complete one orbit, so Kepler will monitor those stars for at least three years to confirm the planets’ presence.
Astronomers estimate that if even one percent of stars host Earth-like planets, there would be a million Earths in the Milky Way alone. If that’s true, hundreds of Earths should exist in Kepler’s target population of 100,000 stars.
Ceres as seen by the Hubble Space Telescope in 2004 (HST)
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It has been theorised for a long time that the dwarf planet Ceres may be harbouring a lot of water. With the promise of water comes the hope that life may be present on this little world orbiting the Sun in the asteroid belt. You may be forgiven in thinking that the search for life in the Solar System has gone a little crazy, after all, we haven’t found life anywhere else apart from our own planet. However, if we do discover life on other planetary bodies apart from Earth, perhaps the panspermia hypothesis is more than just an academic curiosity. So why is Ceres suddenly so interesting? Firstly, it probably has water. Secondly, the ex-asteroid is so small that fragments of Ceres could have been kicked into space by meteorite impacts more readily than other larger planetary bodies, making it a prime candidate for seeding life on Earth…
Now THAT is a dwarf planet: The size comparison of the Earth, Moon and Ceres (NASA)There’s always good news to outweigh the bad. In 2006 when the International Astronomical Union (IAU) demoted Pluto from being a “planet” to a “dwarf planet”, Ceres had the reversal in fortune in that it was promoted from being just another big asteroid to a dwarf planet. Now this tiny world has become a little more important.
In 2007, NASA launched the Dawn spacecraft that will reach this mysterious dwarf planet in 2015. It will be the first mission to this region of the Solar System, and it is making good progress (Dawn just completed a gravitational flyby of Mars). So far, since its discovery in 1801 by Giuseppe Piazzi, we have only managed to attain some fuzzy images of Ceres using the Hubble Space Telescope (pictured top). As can be seen from the size comparison, trying to spot Ceres is quite a task, it is tiny (in fact, it is the smallest classified dwarf planet out there, so far). This may be the case, but it is its low mass that has excited a University of Giessen (Germany) researcher who is studying the possibility that Ceres could support life.
Although it is unknown whether or not Ceres has liquid water oceans, Joop Houtkooper believes that if it does, basic life forms may be thriving around hydrothermal vents in the hypothetical Ceres oceans. However, it is not clear how these proposed oceans can stay in a liquid state, as it seems unlikely there is significant tectonic activity (as it has very little mass to sustain a long-term molten core) and it is not orbiting a tidally disruptive body (like the icy moon Europa around Jupiter – extreme tidal forces maintain sub-surface oceans in a warm state). However, the idea remains as Ceres has a lower escape velocity than any other planetary body, meaning that microbes (hitch-hiking on fragments of Ceres) could have been kicked into space with more regularity than other planets, such as Mars.
“I looked at the different solar system bodies which either had or currently have oceans,” Houtkooper explains. “The planet Venus probably had an ocean early in its history, but the planet’s greater mass means that more force is needed to chip off a piece of the planetary crust and propel it in the direction of the Earth. Smaller objects like Ceres have lower escape velocities, making it easier for parts of it to be separated.”
Artist impression of the Dawn spacecraft exploring the asteroid belt (NASA)Also, Ceres appears to have gotten off fairly lightly during the Late Heavy Bombardment, allowing it to retain its surface water. If the Earth had any life before this era, it is possible that the violent impacts sterilized the planet. In this case, it is possible life arrived to Earth via a shard of another planetary body in the form of a meteorite.
Although calculations suggest Ceres could be a very likely candidate as the source of panspermia, eventually leading to life on Earth, the question as to whether Ceres is even a hospitable place for life to form is doubtful. Also, if Ceres was saved from the worst impacts during the Late Heavy Bombardment, and it appears to have retained the majority of its water through lack of impacts, surely Ceres fragments would be a very rare meteorite component?
Still, it is an engrossing area of research, but we’ll have to wait until Dawn arrives in Ceres orbit in a little over five years time before we arrive at any answers…
This sequence of three images, obtained by NASA's Cassini spacecraft over the course of about 10 minutes, shows the path of a newly found moonlet in a bright arc of Saturn's faint G ring. Image credit: NASA/JPL/Space Science Institute
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Saturn’s G ring has been the ring without a moon, until now. In trying to understand the mysterious G ring, Cassini scientists have taken every opportunity they can to take a closer look at what could be creating the ring. In 2007, scientists identified a possible source of the G ring as relatively large, icy particles that resided within a bright arc on the ring’s inner edge. But the researchers thought there had to be more than just these particles “shepherding” the ring, and concluded that there had to be larger, yet-unseen bodies hiding in the arc. Their persistence has now paid off, as a small moonlet has been found within the ring. “Before Cassini, the G ring was the only dusty ring that was not clearly associated with a known moon, which made it odd,” said Matthew Hedman, a Cassini imaging team associate at Cornell University in Ithaca, N.Y. “The discovery of this moonlet, together with other Cassini data, should help us make sense of this previously mysterious ring.” The sequence of three images above, obtained by NASA’s Cassini spacecraft over the course of about 10 minutes, shows the path of the moonlet in a bright arc of Saturn’s faint G ring.
Cassini imaging scientists analyzing all the images acquired over the course of about 600 days found the tiny moonlet, about a half a kilometer (about a third of a mile) across, embedded within a partial ring, or ring arc, previously found by Cassini in Saturn’s tenuous G ring.
Scientists imaged the moonlet on Aug. 15, 2008, and then they confirmed its presence by finding it in two earlier images. They have since seen the moonlet on multiple occasions, most recently on Feb. 20, 2009. The moonlet is too small to be resolved by Cassini’s cameras, so its size cannot be measured directly. However, Cassini scientists estimated the moonlet’s size by comparing its brightness to another small Saturnian moon, Pallene.
Hedman and his collaborators also have found that the moonlet’s orbit is being disturbed by the larger, nearby moon Mimas, which is responsible for keeping the ring arc together.
This brings the number of Saturnian ring arcs with embedded moonlets found by Cassini to three. The new moonlet may not be alone in the G ring arc. Previous measurements with other Cassini instruments implied the existence of a population of particles, possibly ranging in size from 1 to 100 meters (about three to several hundred feet) across. “Meteoroid impacts into, and collisions among, these bodies and the moonlet could liberate dust to form the arc,” said Hedman.
Saturn’s rings were named in the order they were discovered. Working outward they are: D, C, B, A, F, G and E. The G ring is one of the outer diffuse rings. Within the faint G ring there is a relatively bright and narrow, 250-kilometer-wide (150-miles) arc of ring material, which extends 150,000 kilometers (90,000 miles), or one-sixth of the way around the ring’s circumference. The moonlet moves within this ring arc. Previous Cassini plasma and dust measurements indicated that this partial ring may be produced from relatively large, icy particles embedded within the arc, such as this moonlet.
Carl Murray, a Cassini imaging team member and professor at Queen Mary, University of London, said, “The moon’s discovery and the disturbance of its trajectory by the neighboring moon Mimas highlight the close association between moons and rings that we see throughout the Saturn system. Hopefully, we will learn in the future more about how such arcs form and interact with their parent bodies.”
Early next year, Cassini’s camera will take a closer look at the arc and the moonlet. The Cassini Equinox mission, an extension of the original four-year mission, is expected to continue until fall of 2010.
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NASA’s Mars Reconnaissance Orbiter unexpectedly rebooted its computer Monday morning, Feb. 23, and put itself into a limited-activity mode, an automated safety response to an anomalous event such as a cosmic ray hit on part of the electronics on board the spacecraft. This is the fifth time since August of 2005 that the spacecraft has gone into safe mode. However, the symptoms from this week’s event do not match any of the prior safe-mode events. “We are going to bring the spacecraft back to normal operations, but we are going to do so in a cautious way, treating this national treasure carefully,” said Jim Erickson of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., project manager for the Mars Reconnaissance Orbiter. “The process will take at least a few days.”
Safe Mode is a precaution programmed for the spacecraft when it senses a condition for which it does not know a more specific response.
MRO engineers are examining possible causes of the event while planning to prepare the spacecraft to resume its scientific investigations of Mars. There has been no reoccurrence of the reboot event.
The spacecraft is in communication with and under control by the flight team. Its batteries are charged and its solar panels are properly generating electricity. The team successfully commanded an increase of more than 10,000-fold in the communication rate Monday afternoon from the rate of 40 bits per second that the orbiter initially adopted when it went into the precautionary “safe” mode.
From the spacecraft data received after communications accelerated, the team gained a preliminary indication that the cause of the reboot might have been a measurement — possibly erroneous — of a brief increase in power load. The event lasted between 200 nanoseconds and 41 seconds. That leads engineers to identify one possible scenario as a cosmic-ray hit that could have caused an erroneous voltage reading that would last 9 microseconds, enough to trigger the reboot.
The reboot occurred at about 4:25 a.m. Pacific Standard Time on Monday, while the orbiter was behind Mars from Earth’s perspective. Engineers hope to have MRO back functioning normally by early next week.
Engineers and scientists for MSL work in JPL's clean room. Credit: JPL
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The Jet Propulsion Laboratory offered a web audience the chance to watch activities in the clean room on February 24 for the Mars Science Laboratory, the car-sized rover set to head to Mars in 2011. A two-hour live video feed on UStream included questions and answers with MSL engineer David Gruel and Ashwin Vasavada, MSL Deputy Project Scientist. The best part, however, was watching a check-out of the MSL “Skycrane,” the brand new landing system, and seeing the different parts of the rover and spacecraft. The Skycrane will lower the rover down to the surface with tethers as it hovers over the planet’s surface. On Tuesday, the Skycrane was hoisted high above the rover as the tethers were deployed. “We’ve just completed an environmental testing campaign for MSL,” said Gruel, MSL manager of assembly, testing and launch operations, where the components are subjected to the various conditions of heat, cold and vibrations of launch and space travel. “Now we’re separating the stages, making sure umbilical works as we expect, and making sure the system will deploy properly.”
Screenshot of JPL's MSL clean room activities on UStream.
During the clean room tests on Tuesday, the Skycrane tethers were only deployed two-thirds of the way. During the actual landing on Mars, the tethers will roll out to about 7.5 meters (24 feet). Only three tethers will hold the big rover as it descends to the surface.
Gruel said after launch, landing is by far and away the biggest challenge of the mission. “We’re heading ballistically towards Mars, and when we hit the atmosphere we’ll have to burn off energy that energy and speed, get the parachutes to work, and then have the Skycrane do its job.”
Visible on the Skycrane are the thrusters that will keep it in the air as the rover descends. Screen shot of the folded up MSL rover.
MSL is a huge rover. Gruel said it is the same size as a Mini Cooper car. Visible in this image is one of the rover’s wheels, and the Pathfinder rover that went to Mars in 1997 is about the same size as just of one of MSL’s wheels. This image below shows the comparisons between the different Mars rovers. Rover comparison. Credit: JPL
Screen shot of MSL's heat sheild.
Here’s a shot of the heatshield and backshell for MSL, which are far bigger than the ones used for the Apollo capsules. The heatsheild pictured is a non-flight heat shield. The insulative material isn’t included on this version, which makes it easier to handle in the clean room.
Then after landing, the challenge will be to come up with interesting science, said Gruel, “just like we’re doing with Spirit and Opportunity, and try to continue to operate as long as possible.” Screen shot of vertical decsent radar.
This is the Terminal Descent Radar and Imager, which will take images as the lander comes down through atmosphere. There are several other cameras on the rover, and Gruel said the cameras will have the ability to create “movies” by taking several pictures quickly in succession. “They won’t be like the latest action packed thriller, but we should be able to see what is like to traverse across surface of Mars,” said Gruel.
Vasavada answered questions in depth about the different scientific instruments on MSL.
“Not only will MSL be a robotic field geologist,” he said, “but it will have a mobile geochemistry laboratory, have the ability to drive up to a rock and sample it, take a scoop of soil, and take to instruments inside the rover to see what minerals are there, the chemistry and if there are any organics. MSL will have a Swiss Army Knife bag of tricks, giving us a virtual presence on Mars.”
“One instrument, Chem Cam has a high powered laser connected to a telescope,” Vasavada continued, “the laser points towards a target, and creates a spark. The instrument observes the spark and all the colors in the spectrum that comes back to see the chemical composition of rocks and soil.” This instrument doesn’t have to be up close to an object to study it, which will increase the areas of study. “There will be some places the rover can’t get to, like up a canyon wall, or down in crater, but this instrument can reach those areas,” Vasavada said. Screen shot of the MSL clean room from UStream video.
A weather station will be on the rover, supplied by scientists from Spain, studying wind, temperature, pressure, and relative humidity.
“We will attack Mars in a bunch of ways, to lend some more definitive answers to if there was liquid water, how long did it flow, how did the mineralogy work in Mars past, was it ever habitable, what were things like in the past and what are they like in the present, or was there any organics, and can we find evidence of past life. It’s a broad mission and everybody is really thrilled.”
The space shuttle Discovery moved to the Kennedy Space Center Launch Pad on Jan. 14, but launch has been postponed until further notice. Credit: NASA/Troy Cryder
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NASA announced yet another delay for the launch of the Discovery STS-119 mission to the International Space Station Friday, marking the fourth time the mission has been postponed.
An all-day review of the craft’s readiness for launch left managers still under-confident about the operations of three hydrogen control valves that channel gaseous hydrogen from the main engines to the external fuel tank. Engineering teams have been working to identify what caused damage to a flow control valve on shuttle Endeavour during its November 2008 flight. NASA managers decided Friday more data and possible testing are required before launch can proceed.
“We need to complete more work to have a better understanding before flying,” said Bill Gerstenmaier, associate administrator for Space Operations at NASA Headquarters in Washington. Gerstenmaier chaired Friday’s Flight Readiness Review.
“We were not driven by schedule pressure and did the right thing. When we fly, we want to do so with full confidence.”
The STS-119 crew members gather in front of the hatch into space shuttle Discovery to place the mission plaque. Standing from left are Mission Specialists Joseph Acaba, Koichi Wakata, Steve Swanson, John Phillips and Richard Arnold and Pilot Tony Antonelli. Kneeling in front is Commander Lee Archambault. Photo credit: NASA/Kim Shiflett January 20, 2009
Besides understanding what happened with Endeavor’s valves last fall, teams also have tried to determine the consequences if a valve piece were to break off and strike part of the shuttle and external fuel tank.
Meanwhile, the Discovery launch date has shifted from Feb. 12, to Feb. 19, to Feb. 22, Feb. 27 and now — as of last night’s briefing — is postponed until further notice. The Space Shuttle Program has been asked to develop a plan for further inspections. The plan will be reviewed during a meeting on Wednesday, Feb. 25 and a new target launch date may be considered then.
The STS-119 mission is supposed to enhance the solar gathering power of the International Space Station so it might support a larger crew. When it does fly, STS-119 will tote two solar array wings, each of which has two 115-foot-long arrays, for a total wing span of 240 feet, including the equipment that connects the two halves and allows them to twist as they track the sun. Altogether, the four sets of arrays can generate 84 to 120 kilowatts of electricity – enough to provide power for more than 40 average homes.
The mission astronauts arrived at the Kennedy Space Center Jan. 19 and have more or less been in standby mode ever since, shuttling back and forth between Florida and the Johnson Space Center in Houston. On Wednesday of this week, STS-119 mission specialists Richard Arnold and Joseph Acaba were in the Neutral Buoyancy Laboratory at Johnson, brushing up on spacewalk procedures. As of Thursday, the astronauts were in launch-countdown mode which included preflight quarantine.
Proctor Crater on Mars during winter. Credit: NASA/JPL/U of AZ
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If you’ve never seen the “Springtime on Mars 2020” video, its a fun (if not Wall-E-ish) view of what Mars could be like sometime in the future. But now in 2009, winter is turning to spring in Mars’ southern hemisphere, and the HiRISE camera on board the Mars Reconnaissance Orbiter is busy snapping high resolution images of planet’s surface. In the winter the dunes shown here in Proctor Crater are covered with seasonal carbon dioxide frost (dry ice). In the spring, the frost gradually evaporates but lingers in protected regions. In this color image bright ice deposits in sheltered areas highlight the ripples on the dunes. Now that MRO has been in orbit for two Martian winters, this image of Proctor Crater can be compared with the images of these dunes that were taken during the first year of MRO’s mission. Scientists are comparing the images to study inter-annual variability. See an image from January 2007 of Proctor Crater below, as well as more new images from HiRISE.
Proctor Crater dune field, 2007. Credit: NASA/JPL/U of AZ
Here’s how Proctor Crater looked two years ago (one Martian late winter ago), in January 2007. The crater is located -47.2 degrees latitude, and 33.9 degrees longitude East. South pole CO2. Credit: NASA/JPL/U of AZ
Every southern winter the south polar region of Mars is covered with an approximately 1 meter deep layer of frozen carbon dioxide (dry ice). In the spring, when the sun begins to warm the surface below the translucent ice, gas flow under the ice carries loose dust from the surface up onto the top.
The dust falls to the surface in fans, whose orientation is determined by the direction of the local wind flow. Fans from one source region pointing in multiple directions show how the wind direction has changed. Narrow fans pointing in just one direction are the most recent. Alternatively, the vent from the surface may have re-annealed, such that these fans were formed over a very limited time span. Hellas Basin. Credit: NASA/JPL/U of AZ
Not quite so far south, at just -28.4 degrees latitude, is Hellas Basin. The detail of this image is amazing, and even though its not a 3-D image, it almost appears so, because of the depth of the detail.
This image shows part of the floor of an impact crater on the northern rim of the giant Hellas Basin.
Hellas includes the lowest elevations on Mars, and may have once held lakes or seas; layered rock outcrops occur around much of the edge of the basin. At this site, a large impact crater (about 90 kilometers across) was partly filled by layered rocks. These rocks on the crater floor are now eroding and forming strange pits.
Here, the layers are mostly exposed on a steep slope which cuts across much of the image. On this slope, they crop out as rocky stripes, some continuous and others not. The material between the stripes is mostly covered by debris, but some areas of exposed rock are visible. The slope is capped by a thick, continuous layer that armors it against erosion; once this cap is gone, the lower material is removed rapidly, forming the steep slope. At the base of this slope, rocks on the floor of the pit appear bright and heavily fragmented by cracks known as joints.
With a target launch date of March 5, NASA’s Kepler mission is just weeks away from its tantalizing journey to peer at faraway stars and the Earth-like planets they may be hosting. Hundreds of astronomers from all over the world have a stake in the data. The United States participants hail from all the usual astronomy hubs, among them Arizona, California, Texas and … Iowa? Steve Kawaler, an astrophysicist at Iowa State University, took a moment to chat with Universe Today about his role in a less-publicized goal of the Kepler mission — and his research out of a less-publicized astronomy program.
Q. Why Iowa?
Kawaler: Iowa’s a great place. I’m originally a New Yorker, and went to grad school at the University of Texas, but landing at Iowa State (mostly by chance) still feels right.
(Still Kawaler:) You can get a lot of work done here. We’ve organized and run the Whole Earth Telescope from here for about 10 years. A few years ago [in 2004], the WET team showed a pulsating white dwarf (BPM 37093, but later dubbed the ‘Diamond Star’) may truly be crystalline. Finding one of the biggest diamonds in the cosmos and announcing it around Valentine’s Day was pretty fun! I’ve been part of some big collaborations where nearly all the work is done remotely, and that is important as we stare at the mountain of data we’re about to see.
Q. What’s your role in the Kepler mission?
Kawaler: I serve on the Steering Committee for the Kepler Asteroseismology Research Consortium. We’ll use the exquisite time-series measurements of the brightness of over 100,000 stars to measure their internal properties. The KASC has over 250 scientists involved, and the Steering Committee is charged with helping organize and coordinate their efforts in reducing and interpreting the data.
Q. What’s most exciting about the science in this mission?
Kawaler: The most exciting discovery will be the discovery of Earth-like planets around other stars. It’s what we all wonder about – are there other planets out there that host life? That said, most of the stars that Kepler examines won’t show any signs of planetary transits … but the data will provide a gold mine of information about how stars behave. From the point of view of my own research, the most exciting thing that will come out will be improvement, by a factor of almost 100, in the measure of brightness of over 100,000 stars. Asteroseismologists are drooling at this prospect, because we expect to find oscillations in many stars, but this huge increase in sensitivity is bound to reveal new phenomena that we can’t even guess at yet.
Q. A press release described part of your interest as “peering into stars.” Can you elaborate?
Kawaler: Until very recently, everything we know about stars, we learned from looking at the outsides. When you want to really need to know what’s going on, you need some sort of probe that goes beneath the surface. For the Earth, seismic waves generated by earthquakes give you that kind of probe. For stars, we have to measure their vibrations from (very!) far away. Those vibrations produce only tiny signals — very subtle brightness variations. We can also look at how the surfaces move up and down and use those as a measure of the oscillations that are going on inside. Once we do make those measurements, we use the tools that terrestrial seismologists have developed, along with some of our own that are adapted to the special circumstances within stars, to probe the insides of the stars.
Q. Why can’t we do this work from Earth?
Kawaler: The short answer is that we can, sort of, but Earth is a really poor place to do this kind of work. An astronomer can only look at a star for a couple hours a night before the star sets or the sun comes up. It’s kind of the equivalent of listening to Beethoven’s 5th Symphony and listening to every third note. You can sort of do it from the ground by putting together a network of telescopes. We’ve had some remarkable successes. But it’s much easier if you can observe from a platform that isn’t rotating. And if that platform is above the atmosphere, you get the added benefit of a direct line of sight to the star that doesn’t have the atmosphere degrading the image. With continuous views and no atmosphere, Kepler can do way, way better than we can from the ground.
6. Is this helping to realize a life-long ambition for you?
Kawaler: Absolutely – I’ve always been a space program ‘geek.’ I grew up in the 60s. My older brother grew up in the 50s, and he got caught up in the whole Sputnik thing. There were all these books and toys about space; I picked them up and was instantly fascinated. Later, I was just riveted to the TV all the time, watching Gemini and the Apollo missions. I guess I still haven’t grown out of it. My brother is one of the few rabbis that dresses as Captain Kirk on Purim, Jewish Halloween, so I guess he didn’t grow out of it, either. I’m actually heading down to Florida for the launch, with my father, so he can finally be convinced I didn’t have to be a ‘real doctor’ — I can be a PhD.
