NASA Scientists Build Harpoon to Shoot Comets

By Joseph Castro, InnovationNewsDaily Staff Writer
Space.com | SPACE.com – Fri, Dec 16, 2011

Captain Ahab may have wanted to harpoon a giant white whale, but NASA has a whole other target in mind.

Scientists at NASA’s Goddard Space Flight Center are designing a small harpoon that would fire into and collect samples from nearby comets. Because comets are frozen chunks of ice and dust dating back to the formation of our solar system, they may hold clues to the origin of the planets and life as we know it.

“One of the most inspiring reasons to go through the trouble and expense of collecting a comet sample is to get a look at the ‘primordial ooze’ – biomolecules in comets that may have assisted the origin of life,” Donald Wegel, lead engineer for the project, said in a statement.

Previous NASA missions have already found amino acids – molecules that are important for life and serve as the building blocks of proteins – in comets and meteorites. The new project could discover other ingredients necessary for life, supporting the theory that comet and meteorite impacts may have given a boost to the development of life on Earth by delivering vital biomolecules.

Another goal of collecting comet samples is to figure out how comets are formed. This information would provide scientists with important details on how best to deflect any dangerous space rocks hurling toward Earth.

The NASA team is currently trying to figure out the best tip design, explosive powder charge, mass and cross-section for the harpoon. To do this, they are using a six-foot tall crossbow with a half-inch thick steel cable bow string to fire harpoon tips at various speeds into different materials, such as sand, ice and rock salt. They are also developing a sample collection chamber to nestle into the hollow tip. “”[The chamber] has to remain reliably open as the tip penetrates the comet’s surface, but then it has to close tightly and detach from the tip so the sample can be pulled back into the spacecraft,” explained Wegel.

NASA envisions that a single spacecraft would carry multiple harpoons with a variety of powder charges to handle different areas on a comet. The spacecraft would rendezvous with a comet, choose a target and fire the appropriate harpoon based on the presumed material composition of the area. The open collection chamber will gather samples as the harpoon tip dives deeper into the surface of the comet. Once the harpoon reaches its maximum depth, the collection chamber will snap shut and the spacecraft will reel it in, leaving the harpoon tip in the comet. This design will allow scientists to collect comet samples without the difficulty of actually having land on the comet.

The NASA team is still in the proof-of-concept stage for the project. Once they prove that the harpoon will work, they will have to apply for funding to build the instrument.

Comet Lovejoy Survives Fiery Plunge Through Sun, NASA Says

By Mike Wall , SPACE.com Senior Writer Space.com
SPACE.com – Fri, Dec 16, 2011

A newfound comet defied long odds on Thursday (Dec. 15), surviving a suicidal dive through the sun’s hellishly hot atmosphere, according to NASA scientists.

Comet Lovejoy's Death-defying Escape

Comet Lovejoy plunged through the sun’s corona at about 7 p.m. EST (midnight GMT on Dec. 16), coming within 87,000 miles (140,000 kilometers) of our star’s surface. Temperatures in the corona can reach 2 million degrees Fahrenheit (1.1 million degrees Celsius), so most researchers expected the icy wanderer to be completely destroyed.

But Lovejoy proved to be made of tough stuff. A video taken by NASA’s Solar Dynamics Observatory (SDO) spacecraft showed the icy object emerging from behind the sun and zipping back off into space.

“Breaking News! Lovejoy lives! The comet Lovejoy has survived its journey around the sun to reemerge on the other side,” SDO researchers tweeted.

SDO is one of many instruments that scientists — eager to record and study the comet’s presumed demise — trained on Lovejoy as it streaked toward the sun.

“We have here an exceptionally rare opportunity to observe the complete vaporization of a relatively large comet, and we have approximately 18 instruments on five different satellites that are trying to do just that,” Karl Battams, a scientist at the Naval Research Laboratory in Washington, D.C., wrote on the Sungrazing Comets website, before Lovejoy’s closest solar approach.

Battams runs the website, which is devoted to comets discovered by two different spacecraft: NASA’s Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO), which is operated jointly by NASA and the European Space Agency (ESA).

Battams greeted news of Lovejoy’s improbable escape with surprise and delight.

“I expected a diffuse dust tail to survive (for several hours) before fading away but NOT any kind of nucleus!” he tweeted. “I’ve worked with sungrazers for 8yrs; today was the most amazing day I’ve ever had with them!”

Preparing for the end
Lovejoy has a core about 660 feet (200 meters) wide. It belongs to a class of comets known as Kreutz sungrazers, whose orbits bring them very close to the sun.

All Kreutz sungrazers are thought to be the remnants of a single giant comet that broke apart several centuries ago. They’re named after the 19th-century German astronomer Heinrich Kreutz, who first showed that such comets are related.

Comets plunge into the sun on a regular basis, but they rarely give much advance notice of their suicidal intentions. That’s why scientists were so excited about Lovejoy. Australian amateur astronomer Terry Lovejoy discovered the icy wanderer on Nov. 27, giving researchers plenty of time to map out their observation campaign.

And that campaign has been intense, involving five different spacecraft. In addition to SDO, SOHO and STEREO, scientists planned to use Japan’s Hinode satellite and ESA’s Proba spacecraft to track Lovejoy’s movements, Battams wrote.

NASA also created a website providing updates about the comet’s pass through the corona, as well as images of the event beamed down by SDO. It can be found here: http://sdo.gsfc.nasa.gov/data/lovejoy.php

For his part, Terry Lovejoy said he was happy to have made a contribution, and he marveled a bit at all the attention the comet has been getting.

“It’s been tremendous,” Lovejoy told SPACE.com. “Apparently it’s all over Facebook, and I don’t use Facebook. But there’s a lot of interest. I think a lot of people like the name — the Lovejoy name seems to strike a chord with people.”

A dramatic escape
Lovejoy is quite large for a sungrazing comet, and experts expected it to die an impressive death. The website Spaceweather.com, for example, predicted Lovejoy would blaze as brightly as Jupiter or Venus in the sky as it neared the sun.

Battams also expected a good show, saying the comet might even be visible from the ground around sunset today in the Northern Hemisphere.

“I do think that it will put on a spectacular show for us and will be the brightest Kreutz-group comet that SOHO has ever observed,” Battams wrote last week.

Though the early returns are still coming in, those forecasts appear to be on the money. Observations from various spacecraft do indeed show Lovejoy flaring up significantly as it neared our star.

Researchers will keep analyzing the images to better understand the comet’s daring solar approach. And now skywatchers apparently have another shot to catch a glimpse of the resilient Lovejoy on Friday morning (Dec. 16).

For observers in North America, the comet will rise approximately 5 to 10 minutes before dawn and will be situated to the upper right of the sun. If Lovejoy is still shining at least as brightly as Venus, it may be visible, experts say.

You could also try to spot Lovejoy after the sun comes up, if you’re exceedingly careful. Block the rising sun behind a distant building and focus on the part of the sky 3 to 4 degrees above and to the right of the sun (your clenched fist held at arm’s length is equal to roughly 10 degrees). CAUTION: Never point binoculars or a telescope at or near the sun, and never look directly at our star with the naked eye. Serious eye damage can result.

And don’t get your hopes up, either. The comet may well be too faint to see, experts say.

Note: If you take any good pictures of Comet Lovejoy and would like them to be considered for a future story or image gallery, contact SPACE.com managing editor Tariq Malik at tmalik@space.com.

SPACE.com assistant managing editor Clara Moskowitz (@ClaraMoskowitz) contributed to this story. You can follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

News in Brief: Atom & Cosmos

By Science News Staff
Web edition : 2:58 pm

Sun snot
Someone should teach the Sun some manners. When it sneezed on June 7, the sun blew an enormous glob of dark plasma into space — and NASA’s Solar Dynamics Observatory caught it on tape. The 20,000-degree Celsius eruption — actually rather chilly by solar standards — can be seen raining back onto the sun’s surface in blobs and streamers. Some of the material made a beeline for sunspots hundreds of thousands of kilometers from the eruption site. Scientists say an unstable magnetic filament triggered the eruption, which sent shock waves halfway around the star and blew around 4 trillion kilograms of charged particles away from the sun — one of the largest events of its type measured so far. Gesundheit. —Nadia Drake

Death of a comet
For the first time, astronomers have spotted the final death throes of a comet heading into the sun. Scientists have watched plenty of comets come close to the sun and then vanish, but witnessing the actual destruction is tough, John Brown of the University of Glasgow in Scotland and colleagues report online July 10 at arXiv.org. Their new calculations suggest that lightweight comets explode high above the sun; only comets with nuclei heavier than about 100 billion metric tons manage to reach the surface to die. The Solar Dynamics Observatory photographed such a cometary plunge in early July. —Alexandra Witze

Hottest known planet
Welcome to Hades, a.k.a. WASP-33b. Astronomers have identified this planet, which orbits a star in the constellation Andromeda, as the hottest known. Its surface is a scalding 3,350 degrees Celsius, thanks to the inherent heat of its parent star and the fact that the planet is so close to it, orbiting just once every 1.22 days. A team led by Alexis Smith of Keele University in England reported the finding online July 8 in the Monthly Notices of the Royal Astronomical Society. —Alexandra Witze

Galactic menopause
Both the Milky Way and its neighbor, the Andromeda galaxy, could be in the midst of a midlife crisis. Astronomers have used computer models and galaxy surveys to assess how far the two galaxies have come in their life cycle, as measured by the color of their stars. Both appear to be roughly halfway between young blue stars and red older stars, a team from Swinburne University of Technology in Hawthorn, Australia report in the August 1 Astrophysical Journal. Scientists may thus be able to examine an important galactic life change as it happens. —Alexandra Witze

NASA Deep Impact spacecraft flies by small comet

By ALICIA CHANG
Thu Nov 4, 9:00 pm ET

PASADENA, Calif. – A NASA spacecraft sped past a small comet Thursday, beaming pictures back to Earth that gave scientists a rare close-up view of its center. Mission controllers burst into applause upon seeing images from the flyby that revealed a peanut-shaped comet belching jets of poisonous gases.

“It’s hyperactive, small and feisty,” said mission scientist Don Yeomans of the NASA Jet Propulsion Laboratory.

The close encounter occurred 13 million miles from Earth when the Deep Impact craft, hurtling through space, flew within 435 miles of comet Hartley 2. It’s only the fifth time that a comet’s core has been viewed up close.

Scientists are interested in comets because they’re icy leftovers from the formation of the solar system about 4.5 billion years ago. Studying them could provide clues to how Earth and the planets formed and evolved.

“The scientific work is just beginning now,” principal investigator Michael A’Hearn, of the University of Maryland, said at a post-mission news conference. “The engineers did a fantastic job of getting us data. Now we have to make sense of it.”

Thursday’s flyby is actually an encore mission for Deep Impact. It set off cosmic fireworks on July 4, 2005, when it fired a copper probe that crashed into comet Tempel 1. The high-speed collision spewed a cloud of debris into space, giving scientists their first peek of the interior.

After the $333 million comet-buster, NASA recycled Deep Impact for a new mission to visit another comet. It was supposed to target comet Boethin in 2008, but it was nowhere to be found. Scientists theorized the comet may have broken up into small pieces.

Deep Impact was then redirected to Hartley 2. Roughly 1 1/2 miles long, Hartley 2 is the smallest comet to be photographed up close. On its way there, the craft spent several months scanning a cluster of nearby stars with known planets circling them.

While its latest task lacks the Hollywood drama of the Tempel 1 crash, researchers still consider it an important mission. Unlike in 2005, viewers could not see Thursday’s comet encounter in real time since the craft’s antenna was not pointed at Earth as it flew past Hartley 2.

“There are a lot of open questions about comets and their life cycle,” said project manager Tim Larson of JPL, which manages the $42 million encore mission. “We have so little data that every time we have an opportunity to go near a comet, it’s a chance to expand our knowledge.”

Since September, Deep Impact has been stalking Hartley 2 like a paparazzo, taking images every 5 minutes and gathering data. It’s the first craft to visit two comets.

Deep Impact will observe Hartley 2 until Thanksgiving and then wait for further instructions from NASA. The space agency has not decided whether to reuse Deep Impact again. The craft does not have enough fuel on board to do another flyby.

The latest images add to scientists’ cometary photo album, said astronomer David Jewitt of the University of California, Los Angeles, who had no role in the project.

“We’re visual animals and nothing seems wholly real to us until we have a nice picture of it,” Jewitt said.

Hartley 2 passed within 11 million miles of Earth on Oct. 20 — the closest it has been to our planet since its discovery in 1986.

British-born astronomer Malcolm Hartley, who discovered the comet, said he never imagined a spacecraft would get so close to his namesake find.

“When I saw the comet, it was millions and millions of kilometers away,” he said. “I’m extremely excited and feel very privileged. After all, I only discovered it.”