380:, Ostro noted that while the asteroid impact hazard is a long-term risk to any civilization, the risk associated with maintaining an active deflection program is higher, because it is just as easy to deflect an asteroid to impact Earth as to prevent it from doing so. Ostro advocated for continued funding of the
458:– one of the first binary near-Earth asteroids known. The shape of the primary (alpha) has been determined by inversion of radar images. This enabled studies of the orbital evolution of the secondary (beta), which is in turn coupled to the system's orbit around the Sun by
360:, producing the first resolved radar images of an asteroid, which they later used to construct a model of the object. Following the further development of imaging and shape reconstruction techniques by Ostro, Hudson, and Christopher Magri, and the upgrade of
345:. Beginning in the early 1980s, Ostro led the development of radar imaging and shape-reconstruction techniques, first determining only outer limits of targets' shapes, then deriving three-dimensional shape models.
191:. Ostro led radar observations of numerous asteroids, as well as the moons of Jupiter and Saturn, Saturn's rings, and Mars and its satellites. As of May 2008, Ostro and his collaborators had detected 222
852:
535:, have refined knowledge of their orbits and show that their surfaces are coated with very low density (~1 g/cm) material, most likely fine-grain dust, to a depth of several meters.
318:
31:
210:
He died
December 15, 2008, due to complications related to cancer. He has been remembered fondly by his colleagues for both his personal and professional contributions.
847:
515:. In many cases, radar astrometry has excluded possible Earth impacts from trajectory predictions years before optical astrometry would have been able to do so.
325:, also known as 1999 KW4, a binary near-Earth asteroid observed by Ostro and his collaborators. This shape model was obtained by inversion of radar images.
872:
634:
420:– the first near-Earth asteroid imaged well enough to determine its shape, which is two distinct 0.9 km lobes in contact (a contact binary).
832:
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To explore the dynamical implications of these observations in detail, Ostro collaborated with Steven
Chesley, Jon D. Giorgini,
862:
259:
97:
857:
842:
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563:
376:, placing particular emphasis on the need to characterize asteroids before any deflection attempt. In a paper with
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The
Structure of Saturn's Rings and the Surfaces of the Galilean Satellites as Inferred from Radar Observations
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553:
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Radar provides extremely accurate measurement of the positions and velocities of target objects, and such
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Ostro, S.J.; et al. (1988). "Asteroid shapes from radar echo spectra: A new theoretical approach".
306:
523:
Ostro worked on radar observations of the icy satellites of
Jupiter and Saturn, particularly with the
452:– a very small (30 m wide) asteroid that spins so quickly that it has negative effective gravity.
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8:
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from observations by Ostro's group have been essential to predicting
Apophis' trajectory.
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787:. Division for Planetary Sciences. The American Astronomical Society. Archived from
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406:– the first near-Earth asteroid confirmed to be metallic. The estimated amount of
594:
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Ostro, S.J.; Sagan, Carl (1994). "Cosmic collisions and galactic civilizations".
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Ostro, S.J.; et al. (1979). "Radar observations of asteroid 1 Ceres".
587:
478:– an approximately 1 km wide asteroid with a possible Earth impact in 2880.
397:
179:(March 9, 1946 – December 15, 2008) was an American scientist specializing in
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in the mid-1990s, the number of radar observations increased dramatically.
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in 1984. Ostro headed JPL's
Asteroid Radar group, and was a member of the
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of near-Earth objects has been recognized as crucial to dealing with the
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508:
489:
377:
443:
337:, radar observations of asteroids were restricted to measurements of
309:, awarded for acknowledged eminence in the Earth and Space sciences.
251:
317:
407:
569:
NASA Medals for
Exceptional Scientific Achievement (1991 and 2004)
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403:
439:– a large near-Earth asteroid that rotates exceptionally slowly.
302:
141:
853:
Massachusetts
Institute of Technology School of Science alumni
387:
329:
Much of Ostro's career focused on the development of asteroid
30:
333:. In early experiments, such as the first radar detection of
805:
734:
184:
294:
785:"Ostro was the recipient of the 2003 DPS Kuiper Prize"
410:-group metals in 1986 DA is comparable to that in the
527:
RADAR instrument. Radar observations of Mars' moons,
372:
Ostro was an early participant in discussion of the
472:(radiation force changing the orbit) was measured.
285:After completing his graduate work and a year in
848:Cornell University College of Engineering alumni
814:
270:and studied the radar scattering properties of
484:– a near-Earth asteroid that will pass within
348:From August 19 to 22 of 1989, Ostro and
305:. In 2008, Ostro was elected a Fellow of the
698:
663:
388:Notable asteroids observed by Ostro include
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213:
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29:
873:Fellows of the American Geophysical Union
384:, on both hazard and scientific grounds.
367:
293:of astronomy at Cornell before moving to
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414:, the largest source on Earth's surface.
316:
815:
262:in 1978. At MIT, Ostro was advised by
260:Massachusetts Institute of Technology
98:Massachusetts Institute of Technology
582:, asteroid named after Ostro in 1981
468:– the first asteroid for which the
13:
833:People from Somerville, New Jersey
301:RADAR team, studying the moons of
14:
884:
798:
564:NASA Distinguished Service Medal
128:NASA Distinguished Service Medal
586:
558:Division for Planetary Sciences
777:
745:
727:
692:
657:
627:
609:
1:
806:"NASA's Asteroid Radar Group"
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554:American Astronomical Society
197:potentially hazardous objects
863:People associated with radar
721:10.1016/0019-1035(88)90083-8
686:10.1016/0019-1035(79)90027-7
352:observed the contact binary
115:Marguerite, Brian, and Jules
7:
635:"Steven J. Ostro 1946–2008"
617:"Asteroid radar highlights"
289:at MIT, Ostro served as an
10:
889:
858:Cornell University faculty
504:, and Daniel J. Scheeres.
307:American Geophysical Union
843:Rutgers University alumni
739:Jet Propulsion Laboratory
573:
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189:Jet Propulsion Laboratory
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412:Bushveld Igneous Complex
313:Asteroid radar astronomy
214:Education and employment
382:Arecibo Planetary Radar
765:Cite journal requires
735:"Asteroid radar group"
550:Gerard P. Kuiper Prize
374:asteroid impact hazard
368:Asteroid impact hazard
326:
124:Gerard P. Kuiper Prize
56:Somerville, New Jersey
519:Work on other objects
320:
287:postdoctoral research
195:, including 130
838:American astronomers
645:on December 20, 2008
486:geosynchronous orbit
343:radar cross-sections
193:near-Earth asteroids
177:Steven Jeffrey Ostro
42:Steven Jeffrey Ostro
713:1988Icar...73...15O
678:1979Icar...40..355O
566:, posthumous (2010)
358:Arecibo Observatory
291:assistant professor
280:Arecibo Observatory
276:Galilean satellites
244:engineering physics
327:
248:Cornell University
236:Rutgers University
218:Ostro received an
94:Cornell University
90:Rutgers University
16:American scientist
264:Gordon Pettengill
256:planetary science
250:in 1974, and his
205:main belt objects
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165:Gordon Pettengill
135:Scientific career
67:December 15, 2008
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599:Peter J. Cameron
490:Radar astrometry
470:Yarkovsky effect
460:radiation forces
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268:Irwin I. Shapiro
160:Doctoral advisor
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431:(53319) 1999 JM
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331:radar astronomy
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299:Cassini–Huygens
232:ceramic science
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183:. He worked at
181:radar astronomy
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86:Alma mater
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707:(1): 15–24.
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649:December 17,
647:. Retrieved
643:the original
638:
637:. Obituary.
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621:jpl.nasa.gov
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588:Erdős Number
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498:Scott Hudson
495:
466:6489 Golevka
456:66391 Moshup
371:
350:Scott Hudson
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328:
323:66391 Moshup
284:
224:liberal arts
217:
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207:with radar.
199:and 24
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69:(2008-12-15)
868:NASA people
828:2008 deaths
823:1946 births
398:nickel-iron
238:in 1969, a
76:Nationality
817:Categories
604:References
580:3169 Ostro
509:astrometry
488:in 2029.
378:Carl Sagan
278:using the
48:1946-03-09
552:from the
356:from the
258:from the
408:platinum
274:and the
240:Master's
201:binaries
112:Children
80:American
709:Bibcode
674:Bibcode
476:1950 DA
444:1998 KY
404:1986 DA
362:Arecibo
701:Icarus
666:Icarus
574:Eponym
560:(2003)
544:Awards
539:Honors
533:Deimos
529:Phobos
303:Saturn
226:and a
153:(1978)
151:
142:Thesis
120:Awards
107:Jeanne
104:Spouse
58:, U.S.
335:Ceres
246:from
234:from
771:help
651:2008
597:and
531:and
341:and
266:and
252:Ph.D
228:B.S.
220:A.B.
185:NASA
64:Died
38:Born
717:doi
682:doi
556:'s
295:JPL
254:in
242:in
230:in
222:in
187:'s
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