NASA's Mars fleet braces for comet encounter

Comet Siding Spring is hurtling toward its Red Planet rendezvous with Mars, while NASA's Mars spacecraft are aiming their instruments at it and moving themselves out of harm's way.

NASA
An artist's concept depicts Comet Siding Spring (2013 A1) hurtling towards Mars. Closest approach to Mars comes on October 19, 2014.

A comet will give Mars a historically close shave next weekend, and NASA aims to be ready for the dramatic cosmic event.

The space agency has already trained a number of its science assets on Comet Siding Spring, which will zoom within 87,000 miles (139,500 kilometers) of Mars on Oct. 19 — about one-third the distance between Earth and the moon. And NASA's fleet of Red Planet orbiters and rovers will be watching on the big day, studying the comet and its influence on Mars' atmosphere.

"On October 19, we're going to observe an event that happens maybe once every million years," Jim Green, director of NASA's planetary science division, said during a news conference today (Oct. 9). "We're getting ready for a spectacular set of observations." [See photos of Comet Siding Spring]

First-time visitor

Comet Siding Spring, also known as C/2013 A1, was discovered in 2013 by astronomer Rob McNaught using Australia's Siding Spring Observatory. The comet is making its first trip through the inner solar system from the frigid, faraway Oort Cloud, which lies about 50,000 astronomical units from the sun. (One astronomical unit, or AU, is the average distance between Earth and the sun — about 93 million miles, or 150 million km).

Because Siding Spring has never been "heat-treated" before, the incoming comet likely remains largely unchanged since its formation 4.6 billion years ago, researchers said. So studying its composition and behavior should provide clues about the conditions that existed at the birth of the solar system.

"That's one of the reasons we study comets — they're the remnants of our solar system's formation," said ?Padma Yanamandra-Fisher, a senior research scientist at the Space Science Institute's Rancho Cucamonga branch in California.

Observations by a number of missions, including NASA's Hubble, Swift, Spitzer and NEOWISE spacecraft, have already returned some data on Siding Spring. For example, researchers think the comet's core is between 0.5 miles and 5 miles (0.8 to 8 km) in diameter. Further, the fuzzy cloud (or coma) surrounding Siding Spring's nucleus is about 100,000 miles (160,000 km) wide at this point, and its tail stretches for about 300,000 miles (480,000 km), scientists said.

But the real show will begin Oct. 19. NASA's three Mars orbiters — Mars Odyssey, the Mars Reconnaissance Orbiter (MRO) and the newly arrived MAVEN spacecraft — will observe Siding Spring's flyby from space, while the agency's Opportunity and Curiosity rovers will watch from the Red Planet's surface.

The goal is to learn more about the comet's size, rotation speed, activity and composition, researchers said. The interactions between comet particles and Mars' atmosphere could also help scientists better understand the Red Planet's air. MAVEN is particularly well suited to perform this latter task, since the mission was designed to study Mars' upper atmosphere (MAVEN is short for Mars Atmosphere and Volatile Evolution).

If all goes according to plan, MRO will take the first-ever good pictures of an Oort Cloud comet's nucleus. And Opportunity and Curiosity could make some history as well, if Martian dust storms don't cloud up the atmosphere too much.

"We certainly have fingers crossed for the first images of a comet from the surface of another world," said Kelly Fast, program scientist at NASA's planetary science division. "That would be really exciting."

Various instruments and assets will continue to watch Siding Spring after the flyby, following the comet as it recedes into space.

Protecting the spacecraft

Siding Spring will barrel past Mars at about 126,000 mph (203,000 km/h) on Oct. 19 — so fast that even tiny particles shed by the comet could do some serious damage to an orbiting spacecraft. So NASA has taken pains to maneuver its Red Planet orbiters out of harm's way.

"When Mars gets very close to the dust tail, which is about 100 minutes after closest approach, all our spacecraft will be on the opposite side of the planet," Green said. "So the planet will provide the additional protection we believe we need to be able to make these observations safely."

Curiosity and Opportunity aren't in any danger, researchers said; the Mars atmosphere, while just 1 percent as dense as that of Earth, is still substantial enough to protect the rovers from incoming comet material.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @SpacedotcomFacebook orGoogle+. Originally published on Space.com.

Copyright 2014 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to NASA's Mars fleet braces for comet encounter
Read this article in
https://www.csmonitor.com/Science/2014/1010/NASA-s-Mars-fleet-braces-for-comet-encounter
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe