Random Walk

LISA will measure ripples in space- time.

signals, gravitational-wave detectors such as LISA mea- sure waves from all directions, as an ear does. In this way, detecting gravitational waves is like hearing, and with so many potential sources out there, the trick is to figure out which is the black hole and which is the white dwarf. “It’s like listening to an orchestra and trying to tell which is the cymbal and which is the flute, or which is the first violin and the second violin,” says E. Sterl Phinney (BS ’80), profes- sor of theoretical astrophysics, chair of the LISA Science and Sources Working Group, and the leader of the team that A S PACE - TIME S YMPHONY developed NASA’s Beyond Einstein program. LISA will address a myriad of topics, from the astrophysics of black If you could hear the their own undulations of be capable of detecting more holes to particle physics, to sounds of space and time, space-time. sources. When launched, it fundamental mysteries about the universe would be a noisy Although first predicted by will be the only instrument the birth of the universe and place. When those bizarre, Einstein’s theory of general of its kind in space, a mission the nature of gravity. In Sep- light-bending, space-curving, relativity in 1916, gravita- that will observe the universe tember, the National Research and time-warping objects— tional waves have yet to be de- as never before, listening to Council, which provides black holes, neutron stars, tected. While scientists hope the cosmic cacophony that so science policy advice for the and white dwarfs—meet, ground-based observatories far has been silent to us. government, recommended mingle, and merge, they dis- like the Laser Interferometer Gravitational waves are that LISA be made the flag- turb the fabric of space-time, Gravitational-Wave Observa- vibrations of space-time itself, ship mission of the Beyond sending ripples of gravita- tory (LIGO), run by Caltech and they jiggle everything Einstein program. tional waves across the cos- and MIT, will identify a signal they pass through, such as a Among the more promis- mos. But it’s not just black soon, detection is virtually planet or spacecraft—similarly ing phenomena the spacecraft holes and their brethren that guaranteed by the much-an- to how sound waves jiggle will study is the merging of create these waves. The Big ticipated Laser Interferometer the tiny bones in your ear, supermassive black holes. Bang itself, and maybe even Space Antenna (LISA). LISA allowing you to hear. Unlike These events are some of the more exotic objects called will aim at much lower fre- most telescopes, which point most violent and powerful cosmic superstrings, all make quencies than LIGO, and will in a certain direction to detect in the universe, and likewise

36 ENGINEERING & SCIENCE NO . 4 2 0 0 7 produce some of the strongest LISA should also be able to frequency. How quickly the and are detected, they would gravitational waves. When detect a supermassive black orbital frequency changes tells be a great discovery, he says. two of these behemoths meet, hole eating a relatively tiny scientists how fast the system “It’s something of a long shot, they spiral in toward each one, a few times the mass of is losing energy, which then but it’s a really exciting op- other. According to astrono- our sun. But because the stel- tells them how strong the portunity.” mers, nearly every galaxy has lar-mass black hole is millions gravitational waves are. Just While the science prom- a supermassive black hole at to billions of times smaller than as light looks dimmer with ises to excite and amaze, the its center, and when galaxies the supermassive one, it works greater distance, the strength spacecraft is a remarkable feat collide, the central black holes as what physicists call a “point of detected gravitational waves of engineering in and of itself. often merge—which can hap- test mass.” As the smaller black drops if the source is farther LISA consists of three identi- pen somewhere between once hole circles its giant partner, it away. By comparing the mea- cal spacecraft in a triangular and 300 times per year. follows every curve of space- sured strength of gravitational formation. In order to detect Astronomers are find- time. The gravitational waves waves with the theoretical the frequencies researchers ing that the evolution and betray its path, telling physi- value, researchers can figure want, the triangle has to be formation of galaxies are cists how space-time bends out how far away the system gigantic—five million kilome- inextricably tied to their around the supermassive black is. If the two black holes are ters per side, or the same dis- merger history and to their hole. For the first time, physi- coupled with an electromag- tance you’d cover if you drove central supermassive black cists would find out if black netic source, such as when the to and from Pasadena and holes. But since their black holes behave as they think they black hole eats surrounding New York about 1,120 times. holes are always shrouded in do, Phinney says. gas and dust, LISA will make Each craft holds two identical gas, dust, and stars, scientists Merging supermassive black the most accurate measure- instruments, and each instru- can’t directly observe them. holes could also serve as the ments yet of the universe’s ment encases a shiny, free- Gravitational waves, however, most accurate yardsticks yet expansion. Measuring floating, four-centimeter cube zip through everything at the of the universe. A black hole cosmological expansion means that acts as a test mass. Laser speed of light, and with LISA, binary system, in which two measuring dark energy, the beams that bounce between a researchers would be able to black holes orbit each other, mysterious stuff that makes cube in one craft and a cube make the first direct observa- loses energy as it produces up roughly 70 percent of the in another form the three tions of merging black holes. gravitational waves. The universe. “LISA could revo- sides of the triangle. When a “They will tell us something strength of the waves reflects lutionize dark-energy studies,” gravitational wave zips by, it very fundamental about how how much energy is lost. As Prince says. shifts the distance between the galaxies evolved,” says Tom the system loses energy, the Furthermore, gravitational test masses by a tiny amount. Prince, professor of physics, two black holes spiral closer echoes of the Big Bang give The laser beams also shift, the U.S. mission scientist for together, spinning around astrophysicists a powerful way giving scientists a measure- LISA and cochair of the LISA each other faster and faster, to study the universe during ment of the gravitational International Science Team. increasing the system’s orbital its first second of existence. wave. The shifts in distance Conventional observations, are so small that the instru- by way of electromagnetic ment needs to be accurate to waves—light—only allow re- 10 picometers—smaller than searchers to look back to when any atom. Meanwhile, all this the universe was 300,000 years is trailing Earth by 20 degrees old. Before then, the universe of its orbit around the sun, a was a hot plasma soup, too distance equivalent to 25 mil- thick for light to pass through. lion kilometers. But because gravitational One of the biggest chal- waves can pass through the lenges engineers had to over- primordial soup, LISA may be come was that of designing a able to reveal the universe in its spacecraft that would protect infancy. the test mass and keep it in But wait, that’s not all. its smooth orbit. Given the One of the more exotic gravi- extreme sensitivity of the in- tational-wave sources could strument, normally negligible be vibrating cosmic super- effects such as the force from strings, long, one-dimensional sunlight and the gravitational objects that stretch across the field of the spacecraft itself universe. Waves on those must be accounted for. One strings, which were produced solution was to install micro- during the Big Bang, would thrusters to counteract every At the heart of LISA are the free-floating test masses like this one. Tiny move at the speed of light. inadvertent bump. shifts in distances between the test masses would mean a gravitational They would flop around like In 2010, the LISA Path- a loose garden hose, creating finder mission will test this wave is passing through. The cubes’ polished surfaces reflect lasers between gravitational waves, Phinney delicate ensemble. The the spacecraft to measure the shifts. explains. If these strings exist mission, led by the European

2 0 0 7 ENGINEERING & SCIENCE NO . 4 37 Space Agency and with JPL supplying the thrusters, will test the technology in a true zero-gravity environment. There’s no environment on Earth that’s as quiet as the space environment that LISA will experience, Prince says. So to make sure that research- ers understand how the in- strument works, they have to send a prototype into space. M ARS R OVERS : T HE N EXT G ENERATION The real LISA, a collabo- ration between NASA and ESA, won’t fly until 2018 at the earliest. The greatest hurdle so far, Phinney says, is NASA scientists are seeking last much longer than we closer to the poles. At a con- whether NASA will provide big pieces of an even big- anticipate, as the rovers Spirit ference in late October, the enough funding. “The two ger puzzle to help answer and Opportunity have,” says original 36 proposed landing big questions are when it will the biggest question about project scientist John Grotz- sites were narrowed down to happen and whether the U.S. Mars—was it ever, is it, or inger, who came to Caltech six sites and four alternates, will have a major role in it,” could it possibly be a place for in 2005, after years at the all of which are ±30 degrees Phinney says, noting that the life to exist? Massachusetts Institute of of Mars’ equator. The farthest U.S.—and Caltech in par- The size of a Mini Cooper Technology. Those two rovers poleward proposed site is ticular—has been a scientific and having more instruments are still roaming Mars after Terby Crater, at about 27.5 leader for LISA over the past than any previous Mars rover, landing in 2004; they were degrees south latitude. couple decades. “It would be the one-ton Mars Science originally expected to last 90 MSL will pioneer a tech- a shame if the U.S. were to Laboratory (MSL) will find Martian days. nique called “steered land- just drop out of it.” some of those pieces. Expect- MSL will be fueled by ing” that will get it as close Funding and politics aside, ed to launch in September nuclear power, so it will not as possible to its selected site. the science of LISA sells itself, 2009, it will land in the be as restricted in its opera- The previous rovers bounced drawing enthusiastic support- summer of 2010. During tions as the previous solar- and rolled in their protective ers, Phinney says. Scientists the planned mission, which powered rovers have been. airbags, giving little control are confident the mission will should last one Martian year The MSL can reach higher over where they landed within eventually launch. When (almost two Earth years) it latitudes that get less sunlight their 50- to 100-kilometer it does, scientists can finally will travel 20 miles. each day. Previous rovers had target ellipse. tune in to the universe and “We’re hoping that the to land within 20 degrees of “It’s still not perfect, but its space-time symphony. Mars Science Lab will be the equator, but MSL should now we can land within the —MW able to go much further and be able to get 10 degrees range of a city rather than an

This engineering model of the Mars Science Laboratory’s chassis, dubbed “Scarecrow” because it does not have a brain of its own, makes its way down a hill in JPL’s Mars Yard. MSL will be about twice as long and four times as heavy as the current Mars rovers, Spirit and Opportunity.

38 ENGINEERING & SCIENCE NO . 4 2 0 0 7 entire county,” says Deputy JPL, will identify and analyze rock and mineral types to be Project Scientist Ashwin minerals in rocks and soil. identified in the landscape Vasavada. Previous Mars rovers have from afar. What’s new is the One proposed MSL landing site, MSL is equipped with small used spectroscopy to identify capability to take and store Holden Crater, lies at 26.8 degrees rockets that fire downward elements, but X-ray diffrac- high-def video—in stereo, for a few seconds at a time to tion is far less ambiguous. no less! Now we’ll be able to south latitude. Seen here in control landing speed. The “For understanding geo- watch dust devils form and enhanced color, Holden contains shape of the craft also allows logic history, this is especially whip by in 3-D. MastCam deep gullies carved by running the entry, descent, and land- important,” says Vasavada. has its own internal image water, as well as putative lake-bed ing team to control the angle “The same chemical elements storage, processing, and com- of attack, which determines will take the form of different pression, taking this compu- deposits. One of the latter is the lander’s lift and forward minerals depending on the tationally intensive burden off shown here—the bright material velocity. MSL knows its environment in which they the rover’s main brain. at the base of the cliff. desired trajectory, and sensi- were formed.” Another camera, called tive gyroscopes allow it to cor- These minerals arrange the the Mars Descent Imager rect itself, should something same atoms into different (MARDI), will take pictures push it off course. These tools crystal structures, meaning as the MSL lands. will shrink the landing ellipse that the atoms have different MAHLI, MastCam, and to a mere 10 kilometers or so. three-dimensional spacings. A MARDI are being built by “Mars is now a place beam of X rays shot into each Malin Space Science Systems for sedimentologists,” says different structure will thus be of San Diego, headed by Grotzinger, the Jones Profes- diffracted at a different set of Michael Malin (PhD ’76). sor of Geology. “Using the angles. Due to its bulk and The ChemCam, a collabo- same techniques to see what weight, an X-ray diffractom- ration between France and the the early earth was like, we eter has never been put on a U.S., will use laser pulses to can find out what Mars was, spacecraft before, but CheMin vaporize thin layers of mate- and is, like.” On a table in his is about the size of a laptop rial from Martian rocks or soil office sits a large rock from computer bag. from up to 10 meters away. Australia, whose surface bears MSL will be the first rover A spectrometer will then ripples that look just like the ever equipped with its own identify the newly liberated wave patterns that form in light sources. An ultraviolet atoms, and a telescope will sand at the beach, where the light will be used to make capture detailed images of the tide ebbs and flows. Scientists minerals fluoresce, like the area illuminated by the beam. have already seen ripples like glow-in-the-dark geology dis- ChemCam and MastCam will these on Mars, implying that plays at many science muse- both sit on the rover’s head- water once flowed there. ums. This isn’t being done high mast, helping researchers But now scientists are to make trippy pictures—the decide which objects they going beyond water, seek- fluorescence spectrum will should investigate next. ing compounds containing help identify the minerals in The rover’s Radiation carbon, hydrogen, nitrogen, the rocks. Assessment Detector, provid- phosphorous, and sulfur, all Mounted on the rover’s ed by the Southwest Research essential ingredients for life, arm, the lights are part of Institute, will provide crucial as well as various minerals the Mars Hand Lens Imager information for planning that may indicate organisms (MAHLI), which will take human exploration of Mars, that metabolized these com- extreme close-up pictures and for assessing the planet’s pounds. A suite of instru- of rocks, soil, and perhaps ability to harbor life. ments named Sample Analysis ice, revealing details smaller Canadian researchers are at Mars (SAM), provided by than the width of a human also getting in on the action. NASA Goddard, will analyze hair. MAHLI’s color pictures The Canadian Space Agency samples of material collected will have a higher resolution will be providing the Alpha by MSL’s robotic arm. SAM than the Microscopic Imagers Particle X-ray Spectrometer, includes a gas chromatograph on Spirit and Opportunity, which will be located on the and mass spectrometer that which only take pictures in arm, and will determine the will analyze rock and soil black and white. Using its relative abundances of dif- samples. A tunable laser zoom lens, MAHLI can also ferent elements in rocks and spectrometer will determine focus on objects that the arm soils. the ratios of key isotopes in cannot reach. Russia’s Federal Space the air, providing clues to the Like Spirit and Opportu- Agency is providing the history of Mars’ atmosphere nity, MSL’s Mast Camera will Dynamic Albedo of Neu- and water. see the rover’s surroundings in trons instrument to measure An X-ray diffraction instru- high-resolution color, and its subsurface hydrogen up to ment called CheMin, built by multispectral capability allows one meter below the surface.

2 0 0 7 ENGINEERING & SCIENCE NO . 4 39 This method has been used on JPL’s Mars Odyssey to map N U S TA R R E N UED subsurface water from orbit, but this is the first time a neu- tron spectrometer will land on the surface for a close-up look. Finally, Spain and Finland are taking part with the Rover NASA has given the go- only be reflected and focused proposals selected from 36 Environmental Monitoring ahead to bring a mission back in a telescope if they hit the submitted to NASA’s Small Station to measure atmo- from the dead. Although they mirror at a shallow angle, like Explorers Program, which spheric pressure, temperature, cancelled it in 2006, officials rocks skipping on a pond. funds lower-cost, highly humidity, winds, and ultravio- have revived the Nuclear But since they hit the mirror focused, rapidly developed let radiation levels. Spectroscopic Telescope Array, nearly end-on, it has a very scientific spacecraft. Like any other project, this or NuSTAR. The spacecraft small collection area. In order NASA anticipates that mission has faced challenges. will be the most capable to catch as many as possible, NuSTAR will bridge a gap in “We’re in the sausage-mak- instrument yet to explore the X-ray telescopes have several astrophysics missions between ing stage of it right now,” universe using high-energy X nested mirrors called shells. the 2009 launch of the Wide- said Project Manager Rich- rays. NuSTAR will have two such Field Infrared Survey Explorer ard Cook, referring to the “It’s great that NASA was multiple-mirror systems, each and the 2013 launch of the aphorism attributed to Otto able to restart the mission,” with 130 cylindrical shells James Webb Space Telescope. von Bismarck, “Laws are like says Fiona Harrison, profes- of reflective material. The Besides using high-energy X sausages. It’s better not to see sor of physics and astronomy system was demonstrated on rays to map areas of the sky, them being made.” and NuSTAR principal a balloon-borne experiment the spacecraft will comple- Grotzinger was faced with investigator. “I’m incredibly called HEFT, for High Energy ment astrophysics missions the first of these challenges excited about our planned Focusing Telescope, that that explore the cosmos in about six months ago when science program, as well as Harrison’s group flew in 2005. other regions of the electro- he took over Edward Stolper’s the unanticipated things we Each of the 130 shells is magnetic spectrum. —EN position as project scientist. are bound to discover with a coated with an average of 300 (Stolper, the Leonhard Profes- new telescope this sensitive.” thin layers of alternating high- sor of Geology, had been NASA had scrapped the mis- and low-density materials of appointed Caltech’s provost, sion due to funding pressures varying thicknesses, in order and was unable to give MSL within the Science Mission to reflect a whole spectrum of the time it deserved.) In the Directorate, but NuSTAR will X rays. Other X-ray obser- same week Grotzinger joined now proceed to flight devel- vatories, such as Chandra or MSL, he was told that the opment, with an expected the European Space Agency’s project was $75 million over launch in 2011. XMM-Newton, don’t have its original budget of $1.7 Researchers designed the these multilayer coatings, billion. mission to answer some fun- which limits them to low- Grotzinger needed to cut damental questions about the energy X rays. costs but keep the science universe: What powers the NuSTAR’s X-ray detector program strong. None of the most extremely active galaxies? is a special CCD, or charge- rover’s instruments have been How were the heavy ele- coupled device, analogous to removed from the payload, ments of the universe created? the one in your video camera. but some engineering changes How are black holes distrib- But this one, developed by have been made. These uted through the cosmos? Harrison’s goup in Caltech’s include reductions in design NuSTAR will have more than Space Radiation Lab, is made complexity—for example, a 500 times the sensitivity of of cadmium zinc telluride. rock-grinding tool has been previous instruments that NuSTAR also incorporates changed to a rock-brushing looked for black holes. an extendable structure devel- tool, and MastCam’s zoom The members of Harrison’s oped by JPL and Alliant Tech- capability got scrapped. There team have been working on systems Inc. for the Shuttle will also be fewer spare parts, NuSTAR technology for Radar Topography Mission simplified flight software, and more than 10 years, devel- that will fit the telescope into some ground-test program oping optics that can focus a small, inexpensive launch changes. high-frequency X rays for vehicle. Once in orbit, the MSL will address the the first time. X rays are at arm will be extended to move puzzle of life on Mars, but the high-energy end of the the mirrors some 10 meters the answers won’t come easily, electromagnetic spectrum, away from the detector, bring- HEFT’s mirror system has 72 shells. Grotzinger says. “Like most and easily penetrate most ing the X-ray universe into NuSTAR’s will be nearly identical, things in science, there’s not a materials—which is why doc- focus. silver bullet.” —JS tors use them to see through In November 2003, but bigger and with 130 shells. skin and flesh. X rays can NuSTAR was one of six

40 ENGINEERING & SCIENCE NO . 4 2 0 0 7 An artist’s conception of HD 189733b in orbit around its star.

also have water,” says coauthor Sean Carey of the Spitzer C OSMIC D UST Science Center, which is head- IN THE W IND quartered at Caltech. A team of astronomers had found hints of water on another planet called HD 209458b by analyzing visible- light data taken by NASA’s Don’t let its seemingly vast Hubble Space Telescope. The emptiness fool you: the uni- Hubble data were captured verse is a dirty place. Comets, as the planet crossed in front supernovae, and solar winds of the star, an event called spew microscopic particles of the primary eclipse. Tinetti matter, called cosmic dust, and her team used changes across the universe. Instead in the star’s infrared light as of being a filthy nuisance, the planet slipped by, filtering this cosmic dust may hold the starlight through its outer clues about the history of the atmosphere. The astrono- solar system and the origins H OT AND S TEAMY mers noticed that at each of of life on Earth. “Origins, three different wavelengths, a that’s a big word at NASA different amount of light was these days,” says Jesse (Jack) absorbed—a pattern matching Beauchamp (BS ’64), the that created by water. “Water Ferkel Professor of Chemistry. It may not be the water- in their atmospheres, yet evi- is the only molecule that can Along with Thomas Ahrens world that fields Kevin dence has been hard to come explain that behavior,” Tinetti (MS ’58), the Jones Profes- Costner’s dreams, but the by. “We’re thrilled to have says. “Observing primary sor of Geophysics, Emeritus, exoplanet HD 189733b has identified clear signs of water eclipses in infrared light is Beauchamp has built a device been found to have water on a planet that is trillions of the best way to search for this to extract cosmic dust’s se- vapor in its atmosphere. This miles away,” says lead author molecule.” crets. They call their creation observation provides the best Giovanna Tinetti, a European The water on HD 189733b the Dustbuster, and they hope evidence to date that water Space Agency fellow at the is too hot to condense into it will be put on a future mis- exists on worlds outside our Institute d’Astrophysique de clouds; however, previous sion to the outer planets. own solar system. Paris in France and former observations by several tele- Unlike the Dustbuster The discovery was made postdoc at Caltech’s Virtual scopes suggest that it might you may have in your car or by NASA’s Spitzer Space Planetary Laboratory. have dry clouds, along with broom closet, this gadget isn’t Telescope, which possesses Coauthor Mao-Chang high winds and a hot, sun-fac- a vacuum; it’s a mass spec- a particularly keen ability to Liang (PhD ’06) of Caltech ing side that is warmer than trometer. On Earth, chemists, study nearby stars and their and the Research Center for its dark side. biologists, and those CSI guys planets. HD 189733b lies 63 Environmental Changes in Other authors of the paper use mass spectrometers to light-years away. Taiwan adds, “The discovery include Alfred Vidal-Mad- identify unknown molecules. “Water is the quintessence of water is the key to the jar, Jean-Phillippe Beaulieu, It works on the principle that of life as we know it,” says Yuk discovery of alien life.” David Sing, Nicole Allard, when a molecule or atom is Yung, professor of planetary Wet hot Jupiters are and Roger Ferlet of the charged, or ionized, its behav- science and one of the authors unlikely to harbor any Institute d’Astrophysique de ior in an electric or magnetic of the study published in the creatures. Previous Spitzer Paris; Robert Barber and Jona- field will depend, partly, on July 12 issue of Nature. “It measurements indicate that than Tennyson of University its mass. is exciting to find that it is HD 189733b is a fiery 1,000 College London in England; Cosmic dust flows through as abundant in another solar degrees Kelvin on average. Ignasi Ribas of the Institut the outer reaches of our solar system as it is in ours.” Ultimately, astronomers hope de Ciències de l’Espai, Spain; system at speeds of 10 to 80 HD 189733b swelters as it to use instruments like those Gilda Ballester of the Uni- kilometers per second. Any zips around its star every two on Spitzer to find water on versity of Arizona, Tucson; particles hitting a target days or so. Astronomers had rocky, habitable planets like and Franck Selsis of the Ecole plate on the Dustbuster are predicted that planets of this Earth. “Finding water on Normale Supérieure, France. instantly vaporized, and the class, termed “hot Jupiters,” this planet implies that other —RT energy of the impact strips would contain water vapor planets in the universe could electrons from the molecules,

2 0 0 7 ENGINEERING & SCIENCE NO . 4 41 As the Dustbuster (left) flies through space, dust particles entering its maw (above) smash into a target plate that fragments them into positively charged ions and free electrons. The rebounding positive ions are given a uniform “kick” to the left by the accelerator grid and are then steered into the detector by means of an electric field created by the reflectron rings. producing positively charged something that was smaller cleosynthesis. (Caltech phys- term I like to use. It’s where ions with various amounts in size, used less power, but ics professor Willie Fowler, you suspect there are the con- of kinetic energy. Inside had high performance,” says PhD ’36, won the Nobel Prize ditions for emergent synthesis the Dustbuster, the ions are Beauchamp. While the CDA in Physics in 1983 for work- of organic molecules,” says accelerated by an electric is 17 kilograms and 1 meter ing out the details.) Isotopes Beauchamp. Learning how field and guided towards an long, the Dustbuster is only of the elements—atoms this occurs on the surface of ion detector through a part about 0.5 kilograms and 20 that have the same number Titan could help explain how called the reflectron. This centimeters long. Two types of protons, but a different the molecules of life were first part negates any differences of Dustbusters have now been number of neutrons—are also synthesized on Earth. in kinetic energy between built and tested: Dustbuster I created through nucleosynthe- To study these astrobio- the ions produced by the is designed to sample cosmic sis. Depending on the type logical hotspots, any probe impact. Since the electric dust found streaming through of star and its stage in life, returning to Titan will need field provides each ion with the solar system, while Dust- nucleosynthesis will produce a mass spectrometer. “Mass the same amount of energy, buster II is designed to sample different mixes of elements spectrometers are extremely the time it takes each ion to the high flux of dust from and isotopes, so by analyzing valuable tools for such reach the detector will depend comet tails. the cosmic dust, scientists can missions,” says Kim Reh at on its mass. It’s an ionic drag How can something as sim- learn about the evolution of JPL. Reh was part of a team race—imagine a Honda Civic ple as the mass of a molecule stars. Organic, carbon-based that submitted a proposal dueling a Hummer powered found in a tiny dust particle molecules are synthesized as to NASA in October for a by a Civic engine. Just as the tell us about the history of our the dust flies through differ- mission to “prebiotic” moons heavier Hummer will move solar system? Cosmic dust’s ent chemical environments in the outer solar system, like more slowly, heavier ions will journey often begins in distant in space, like on the tails of Jupiter’s moon Europa and accelerate to lower veloci- stars, from which it is shot out comets. Scientists are very Saturn’s moons Enceladus ties than lighter ions. Faster, across the galaxy through their interested in these, as such and Titan. Beauchamp was lighter ions will arrive at the solar winds or, more dramati- molecules may have served as a consultant to the team. detector first, so monitoring cally, a supernova. Some cos- precursors to DNA, amino “NASA intends to review the when ions reach the finish line mic dust accumulates inside acids, and other biological results of this study by the end determines their masses. interstellar clouds that become molecules on Earth. of this year and select one or “There’s quite a history of unstable and collapse, forming Besides Beauchamp’s two of these science targets for using mass spectroscopy in new stars and planets. Much work on the Dustbusters, he further study in 2008. The space exploration, from the of our solar system, including has also been working on a longer-term goal is to select a Viking program onward,” says the matter in your own body, return visit to Saturn’s moon mission in 2009,” says Reh. Beauchamp. On the recent was once cosmic dust particles Titan. “We have been heavily —MT Cassini-Huygens mission to flying through the galaxy. involved with looking at Titan Saturn, data from the Cassini A dust particle’s com- as a model for early Earth,” Dust Analyzer (CDA) showed position can be read like a says Beauchamp. Lab experi- that Saturn’s outer ring was passport. Inside stars, many ments that simulate condi- formed from dust spraying off of the heavier elements, like tions on Titan and data from of the south pole of its moon, carbon, oxygen, and iron, are the Huygens lander have con- Enceladus. “Having seen forged from lighter elements, firmed the presence of simple the CDA, we were inspired like hydrogen and helium, organic molecules there. to see if we could build through a process called nu- “‘Astrobiological hotspot’ is a

PICTURE CREDITS: 36, 38—NASA/JPL-Caltech; 42 ENGINEERING & SCIENCE NO . 4 2 0 0 7 39—NASA/JPL/Universiy of Arizona; HEFT team; 41—C. Carreau, ESA; 42—Daniel Austin A C HRONOLOGY OF J P L S PACECRAFT

EXPLORERS 1-5 LAUNCH DATES: JAN.–AUG., 1958 MARS PATHFINDER LAUNCH DATE: DEC. 4, 1996 Explorers 1, 3, and 4 discovered and probed the Van Allen Belts. The lander and its Sojourner rover explored an ancient flood plain called Ares Vallis. PIONEERS 3 AND 4 DEC. 6, 1958, AND MARCH 3, 1959 Pioneer 4 became the first U.S. spacecraft in solar orbit. CASSINI-HUYGENS OCT. 15, 1997 A European-U.S. mission orbiting Saturn, Cassini sent the Huy- RANGERS 1-9 1961–65 gens probe to Titan, Saturn’s largest moon. Rangers 7-9 returned images until their planned moon impacts. DEEP SPACE 1 OCT. 24, 1998 MARINERS 1 AND 2 JULY 22 AND AUG. 27, 1962 Tested new technology and took photos of comet Borrelly’s The first to another planet, Mariner 2 studied Venus’s atmosphere nucleus. and surface, and measured the solar wind for the first time. MARS CLIMATE ORBITER DEC. 11, 1998 MARINERS 3 AND 4 NOV. 5 AND 28, 1964 This interplanetary weather satellite was lost on arrival. Mariner 4 took the first close-up photos of another planet, Mars. MARS POLAR LANDER/DEEP SPACE 2 JAN. 3, 1999 SURVEYORS 1-7 1966–68 Aiming for the edge of Mars’ south polar cap and carrying twin Surveyors 1, 3, and 5-7 were the first U.S. landings on the moon. soil probes (Deep Space 2), it was lost during final descent. MARINER 5 JUNE 4, 1967 STARDUST FEB. 7, 1999 Originally a backup Mars craft, Mariner 5 went to Venus. Collected and returned a sample of dust from comet Wild-2. MARINER 6 AND 7 FEB. 24 AND MARCH 27, 1969 WIDE-FIELD INFRARED EXPLORER MARCH 4, 1999 First dual mission to Mars; flew over the equatorial and south A small telescope that lost its cryogenic coolant soon after launch. polar regions. MARINER 8 AND 9 MAY 8 AND 30, 1971 QUICK SCATTEROMETER JUNE 19, 1999 Mariner 9 was the first successful Mars orbiter. Measures ocean wind velocities and directions. MARINER 10 NOV. 3, 1973 ACTIVE CAVITY IRRADIANCE MONITOR SATELLITE DEC. 22, 1999 Pioneered the “gravity assist” concept, swinging by Venus en Monitors the total amount of the sun’s energy reaching Earth. route to Mercury. 2001 MARS ODYSSEY APRIL 7, 2001 VIKINGS 1 AND 2 AUG. 20 AND SEPT. 9, 1975 Now orbiting Mars. The first Mars landings. Each Viking had an identical orbiter GENESIS AUG. 8, 2001 and lander; all four spacecraft completed extended missions. Collected and returned samples of solar wind particles. VOYAGERS 1 AND 2 AUG. 20 AND SEPT. 5, 1977 JASON 1 DEC. 7, 2001 They completed the Grand Tour of the solar system, and are now A follow-up oceanography mission to Topex/Poseidon. heading toward interstellar space. GRAVITY RECOVERY AND CLIMATE EXPERIMENT MARCH 17, 2002 SEASAT JUNE 26, 1978 A U.S.-German mission consisting of two spacecraft flying Tested four radar instruments that studied Earth and its seas. together to measure Earth’s gravitational field. SOLAR MESOSPHERE EXPLORER OCT. 6, 1981 GALAXY EVOLUTION EXPLORER APRIL 28, 2003 Traced the life cycle of ozone in the upper atmosphere. A small ultraviolet telescope that studies galaxy formation. INFRARED ASTRONOMICAL SATELLITE JAN. 25, 1983 MARS EXPLORATION ROVERS JUNE 10 AND JULY 7, 2003 An infrared telescope orbiting above Earth’s atmosphere. The Spirit and Opportunity rovers continue to explore opposite MAGELLAN MAY 4, 1989 sides of Mars. Mapped Venus’s surface. Pioneered the aerobraking technique, SPITZER SPACE TELESCOPE AUG. 24–25, 2003 using a planet’s atmosphere to steer or slow down. A large infrared telescope. One of NASA’s Great Observatories. GALILEO OCT. 18, 1989 DEEP IMPACT JAN. 12, 2005 Orbited Jupiter and dropped a probe into its atmosphere; made Sent an impactor to smash into comet Tempel 1’s nucleus. many flybys of its major moons. MARS RECONNAISSANCE ORBITER AUG. 12, 2005 ULYSSES OCT. 6, 1990 Analyzing Mars’s surface to bridge the gap between surface obser- A collaboration with the European Space Agency, Ulysses moni- vations and measurements from orbit. tors the sun from an orbit around its poles. CLOUDSAT APRIL 28, 2006 TOPEX/POSEIDON AUG. 10, 1992 Provides a never-before-seen 3-D profile of Earth’s clouds. A French-U.S. mission, it measured sea levels every 10 days with an accuracy of less than 10 centimeters. PHOENIX AUG. 4, 2007 A high-latitude lander en route to Mars equipped with a robotic MARS OBSERVER SEPT. 25, 1992 arm to dig into layers with water ice. Lost shortly before arrival at the red planet. DAWN SEPT. 27, 2007 MARS GLOBAL SURVEYOR NOV. 7, 1996 The first craft to orbit two bodies after leaving Earth. It will orbit This orbiter operated longer than any other Mars mission. Vesta and Ceres, two of the solar system’s largest asteroids.

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