Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

Is Eros A Dusty World
Eros - December 17, 1998 - When the Near Earth Asteroid Rendezvous (NEAR) spacecraft eases into orbit around the asteroid 433-Eros on January 10, dust may be one of its first discoveries. Earlier this year, the Mars Observer spacecraft found that the Red Planet's larger moon, Phobos, is coated with dust up to a meter deep.

"That was a surprise," said Dr. James Spann of NASA's Marshall Space Flight Center. "I'm not sure that anyone had an idea of what things look like on these small bodies. I don't imagine that Phobos is so unique that it would have dust and the rest of the small bodies like it won't."

Spann is the director of the Dusty Plasmas Laboratory that was established at NASA's Marshall Space Flight Center earlier this year. It was designed to let scientists study the tiniest motes of dust in space-like conditions. Understanding how dust grains interact with each other, and how they react when exposed to sunlight will provide insight into how planets and stars form.

The Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor observed Phobos, one of the two moons of Mars, on three separate occasions.

The primary objective has been to collect infrared spectra, at different wavelengths ranging from ~6 to 50 micrometers, of Phobos to study its composition and physical properties.

The TES data indicate that the surface temperature in the shadowed region of Phobos is -170 F (~-112 C), while only several kilometers away on the sunlit side of Phobos the temperature is +25 F (~-4 C).

The extreme temperature difference between the night and day sides of Phobos indicates that the surface is composed of very small dust particles that lose their heat rapidly once the Sun has set. In addition, Phobos does not have an atmosphere to help hold heat in during the night.

The Mars Global Surveyor did not see the dust directly, but inferred its presence by measuring how quickly Phobos loses its body heat when the sun sets. The rapid loss is best explained by a huge surface area - much greater than if Phobos were a solid, relatively smooth body.

A coating of dust would provide the increased surface area - the surfaces of all the miniscule grains added together - to radiate heat into space. This is why, for example, a desert cools so quickly after sunset.

So why did dust collect on Phobos, and are Eros and other asteroids also are coated with dust?

NEAR, one of NASA's Discovery-class missions, was launched on Feb. 17, 1996, and has already explored one asteroid, 253 Mathilde, in a quick flyby on June 27, 1997.

NEAR will rendezvous with 433 Eros on January 10 and settle into an orbit that will be gradually tightened until it lands on the asteroid. Although it does not carry a thermal emission spectrometer like that on the Mars spacecraft, it may return some information about dust on Eros.

"It may be that electrostatic forces keep those grains on there," Spann said. Because of the low mass of such bodies, "I don't think that gravity would do it."

Spann noted that we tend to think of gravity as the only dominant force in the universe. Indeed, it holds solar systems and galaxies together, and makes leaving this planet an expensive undertaking. But other forces work at smaller scales.

  • NEAR Mission Control
  • NEAR Press Kit (PDF 1.3MB)
  • Discovery Program
  • SpaceDev (Commercial Asteroid Development Company)

  • Planetary Society Near Earth Objects Page

    NEAR Reports At SpaceDaily

  • NEAR Mission Excitment Growing
  • Eros Orbital Countdown Begins
  • Eros 433 A Speck In The Void
  • NEAR Closing in on Eros 433
  • Mathailde 253 A Battered Shell

    Asteroid and Other Debris at Spacer.Com

  • Comets and Asteroids Get PEPE
  • Get Ready For Deep Space 1
  • Why Study Asteroids?
  • Deep Space 1 Asteroid FlyBy
  • Hubble's Archive of Asteroids
  • Kuipers Reflect In Two Colors
  • Iowa Exploring Sol's Outer Reaches
  • Stardust Spacecraft Assembly Starts
  • Ice and Fire Missions Move Ahead
  • Meteorite Contaminated By Antarctic
  • Flash, Splash and its Over
  • Near Earth Asteroid Opportunities
  • Mathailde 253 A Battered Shell
  • Meteor Fell On Greenland
  • Mini Comets Just Noise?
  • Meteorite Contains No Biological Life

    SpaceDev Articles

  • SpaceDev and UoA Sign NEAP Letter of Intent
  • SpaceDev Finalizes Space Innovations Acquisition
  • NEAP Gets A Stellar Proposal
  • NEAP Assessed As Feasible
  • SpaceDev Selects Asteroid `Nereus' for First Mission
  • SpaceDev Acquires AMROC Patents
  • SpaceDev Signs Jan King For Engineering
  • SpaceDev Issues SEC Statement
  • SpaceDev To Buy UK Space Firm
  • SpaceDev Commissions Pathfinder Engineers
  • Near Earth Asteroid Opportunities

    Thanks for being here;
    We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

    With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

    Our news coverage takes time and effort to publish 365 days a year.

    If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

    SpaceDaily Contributor
    $5 Billed Once

    credit card or paypal
    SpaceDaily Monthly Supporter
    $5 Billed Monthly

    paypal only

    Memory Foam Mattress Review
    Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
    XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.