Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

CRISM Prepares for Mars-Grazing Comet Siding Spring

13.10.2014

On October 19, a comet that has travelled many billions of miles will come within about 87,000 miles of Mars – about one-third of the distance of the Moon from Earth. Comet Siding Spring comes from the Oort Cloud, material left over from the formation of the solar system. “This comet is coming into the solar system straight from the Oort Cloud. It’s likely this is its first time this close to the sun,” said space scientist David Humm, of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

Oort Cloud material, including comets, is scattered through a vast region that begins outside the orbits of Neptune and Pluto and extends a substantial fraction of the distance to Proxima Centauri, the closest neighboring star. Oort Cloud comets can tell scientists about the materials – including water and carbon compounds – that existed during the formation of the solar system some 4.6 billion years ago.


Image Credit: NASA

Artist's concept of comet Siding Spring (C/2013 A1) heading toward Mars.

Studying this close encounter will be the largest fleet of orbiting scientific observatories ever flown to another world, orbiting around (and rolling on the ground of) Mars. These instruments will, for the first time ever, have the chance to make close-up observations of a comet new to the inner solar system. And though it will not be the easiest task, the teams operating these instruments and spacecraft have developed plans to take advantage of this rare opportunity.

“The close fly-by of Mars by Comet Siding Spring is unique, unexpected, and lucky for us,” said Humm, who serves as instrument scientist for the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), built by APL, and one of the instruments on board NASA’s Mars Reconnaissance Orbiter (MRO) that will observe Siding Spring.

Two other MRO instruments observing the comet will be the High Resolution Imaging Science Experiment (HiRISE), a very high-definition camera, and the Context Imager (CTX). Together, all three imagers will attempt to capture data about Siding Spring that is unobtainable from Earth. Though Earth-based observations of Siding Spring will reveal a great deal of information, “CRISM has a significant advantage due to its proximity to the comet at closest approach,” he said.

“CRISM is both a spectrometer and a camera,” Humm explained. “It can identify molecules by the light they emit and characterize minerals by the light they reflect. We can then make an image of any material we identify, and see its distribution. If we’re fortunate, CRISM will be able to detect some features in the comet gas and dust, and we can make images of the distribution of different gases detected and learn something about the nature of the dust.”

There are some challenges. First, though the chances of any comet dust impacting the spacecraft are thought to be very minimal, the decision was made to “hide” the spacecraft in the shadow of Mars after the comet passes, to let the planet absorb any potentially damaging high-speed dust particles that may trail the comet as it passes by.

The greater problem, explained Humm, is that “these instruments are designed for looking at the surface of Mars during daytime, not at a far dimmer comet in the night sky.” But the teams have overcome that challenge as well, and now have full observation plans for Siding Spring.

Siding Spring is small (the nucleus is less than a mile in diameter) and fast (it will pass Mars at about 34 miles per second). CRISM, HiRISE, and CTX were built to study a slowly-moving planet, so they will use MRO’s ability to rotate in order to capture images as the comet speeds by Mars. The instruments will observe the comet repeatedly for two and a half days as it gets closer and closer to Mars before it makes its closest approach. The peak density of comet dust at Mars is expected 98 minutes after closest approach of the nucleus, and the MRO spacecraft will position itself behind the planet at that time.

Last year’s October 1 encounter with Comet ISON – a sungrazing comet that passed within 6.5 million miles of Mars – gave the teams on CRISM and the other Mars observatories a good chance to practice looking at an object hurtling past the planet.

The instruments on MRO are unique in their abilities to study the comet. “HiRISE is the only instrument that can image the nucleus of Comet Siding Spring with more than one pixel, and CRISM will have the best signal-to-noise ratio of any spectrometer that will observe the comet from close up,” Humm said.

Still, comet behaviors are peculiar and may seem random; sometimes they fizzle out, sometimes they get very bright, sometimes they do both. “Comets are very unpredictable,” said Humm. “No two ever seem to be the same. A new comet like Siding Spring will bring surprises.”

Images from Earth-based observatories and the Hubble Space Telescope have shown a typical coma of gas and dust develop as Comet Siding Spring has come closer to the sun. The coma may be larger or smaller when the comet flies by Mars. “If the comet is really active, then we will get good spectra of the coma,” Humm explained. “If the comet is inactive, then some of the compositional results could be in question but we may still see broad color differences.”

For Humm and other scientists on the CRISM and other MRO teams, an event like the encounter with Siding Spring was not even considered during construction and launch of the orbiter and its instruments back in 2005.

“I would have been very surprised if you had told me we were going to use CRISM to look at a comet,” Humm said. "The likelihood of being this close to a new comet is really very small, and we're operating well beyond our design lifetime, so this exciting an opportunity is completely unexpected."

Contact Information

Geoffrey Brown
Public Information Officer
geoffrey.brown@jhuapl.edu
Phone: 240-228-5618

Geoffrey Brown | newswise
Further information:
http://www.jhuapl.edu/newscenter/

Further reports about: Applied Physics CRISM CTX Cloud HiRISE Johns Hopkins Laboratory MRO Mars gas and dust observations small solar system spacecraft

More articles from Physics and Astronomy:

nachricht Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

nachricht Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>