Posted on by Nancy Atkinson

Aged Voyager 1 Does In-flight Gymnastics for Science

Voyager 1 Mission
Artist impression of Voyager 1, the first probe to traverse the heliosheath (NASA)

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She might be old, but she’s still got it where it counts. The 33-year old Voyager 1 probe, flying out near the edge of the solar system conducted a roll program, spinning 70 degrees counterclockwise, and held the position by spinning gyroscopes for two hours, 33 minutes. Voyager performed its in-flight gymnastics on March 7, 2011 and scientists hope the maneuver will help answer the question of which direction is the sun’s stream of charged particles turns when it nears the edge of the solar system.

“Even though Voyager 1 has been traveling through the solar system for 33 years, it is still a limber enough gymnast to do acrobatics we haven’t asked it to do in 21 years,” said Suzanne Dodd, Voyager project manager, based at NASA’s Jet Propulsion Laboratory. “It executed the maneuver without a hitch, and we look forward to doing it a few more times to allow the scientists to gather the data they need.”

Voyager needed to get in the right orientation to enable its Low Energy Charged Particle instrument to gather data.

The last time either of the two Voyager spacecraft rolled and stopped in a gyro-controlled orientation was Feb. 14, 1990, when Voyager 1 snapped a family portrait of the planets. See the image here.

The two Voyager spacecraft are traveling through a turbulent area known as the heliosheath,the outer shell of a bubble around our solar system created by the solar wind. The solar wind is traveling outward from the sun at a million miles per hour. Scientists think the wind must turn as it approaches the heliosheath where it makes contact with the interstellar wind — , which originates in the region between stars.

In June 2010, when Voyager 1 was about 17 billion kilometers (about 11 billion miles) away from the sun, data from the Low Energy Charged Particle instrument began to show that the net outward flow of the solar wind was zero. That zero reading has continued since. The Voyager science team doesn’t think the wind has disappeared in that area, but perhaps has just turned a corner. But where does it go from there: up, down or to the side?

“Because the direction of the solar wind has changed and its radial speed has dropped to zero, we have to change the orientation of Voyager 1 so the Low Energy Charged Particle instrument can act like a kind of weather vane to see which way the wind is now blowing,” said Edward Stone, Voyager project manager. “Knowing the strength and direction of the wind is critical to understanding the shape of our solar bubble and estimating how much farther it is to the edge of interstellar space.”

Voyager engineers performed a test roll and hold back on Feb. 2, just to make sure the spacecraft was still capable. No problems for the old girl, and spacecraft had no problem in reorienting itself and locking back onto its guide star, Alpha Centauri.

This artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around our sun. Image credit: NASA/JPL-Caltech

There will be five more of these maneuvers over the next seven days, with the longest hold lasting three hours 50 minutes. The Voyager team plans to execute a series of weekly rolls for this purpose every three months.

Over the next few months, scientists will analyze the data.

“We do whatever we can to make sure the scientists get exactly the kinds of data they need, because only the Voyager spacecraft are still active in this exotic region of space,” said Jefferson Hall, Voyager mission operations manager at JPL. “We were delighted to see Voyager still has the capability to acquire unique science data in an area that won’t likely be traveled by other spacecraft for decades to come.”

Voyager 2 was launched on Aug. 20, 1977. Voyager 1 was launched on Sept. 5, 1977. On March 7, Voyager 1 was 17.4 billion kilometers (10.8 billion miles) away from the sun. Voyager 2 was 14.2 billion kilometers (8.8 billion miles) away from the sun, on a different trajectory.

The solar wind’s outward flow has not yet diminished to zero where Voyager 2 is exploring, but that may happen as the spacecraft approaches the edge of the bubble in the years ahead.

Voyager is just another good old girl.

Source: JPL

Posted on by Nancy Atkinson

Awe-Inspiring Flythrough of the Saturn System

Ever imagine creating your own IMAX movie? Cinematographer Stephen Van Vuuren is working to do just that, and has created flythough sequences from thousands of images from the Cassini spacecraft’s tour of the Saturn system. The video above is just a sampling of this non-profit, giant-screen art film effort “that takes audiences on a journey of the mind, heart and spirit from the big bang to the near future via the Cassini-Huygens Mission at Saturn,” according to the “Outside In” website.

Continue reading “Awe-Inspiring Flythrough of the Saturn System”

Posted on by Ken Kremer

Apollo 12 anniversary celebrated at Martian Crater as Opportunity blazes ahead

Opportunity arrived at ‘Intrepid’ Crater on Mars during November 2010 and drove around crater rim. See rover wheel tracks at left. Intrepid crater was named in honor of the Apollo 12 lunar module named “Intrepid” – which landed two men on the moon on 19 November 1969. This false color mosaic was assembled from pancam images taken by Opportunity on Sol 2420 (Nov 14, 2010). Mosaic Credit: Kenneth Kremer, Marco Di Lorenzo NASA/JPL/Cornell

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NASA recently celebrated the anniversary of the historic Apollo 12 lunar landing mission with another history making craft – the long lived Opportunity Mars rover. Opportunity traversed around and photographed ‘Intrepid’ crater on Mars in mid November 2010. The crater is informally named in honor of the ‘Intrepid’ lunar module which landed two humans on the surface of the moon on 19 November 1969, some forty one years ago.

Apollo 12 was only the second of NASA’s Apollo missions to place humans on the Earth’s moon. Apollo astronauts Pete Conrad and Gordon Bean precisely piloted their lunar landing spacecraft nicknamed ‘Intrepid’ to a safe touchdown in the ‘Ocean of Storms’, a mere 180 meters (600 feet) away from the Surveyor 3 robotic lunar probe which had already landed on the moon in April 1967. The unmanned Surveyor landers paved the way for NASA’s manned Apollo landers.

As Conrad and Bean walked on the moon and collected lunar rocks for science, the third member of the Apollo 12 crew, astronaut Dick Gordon, orbited alone in the ‘Yankee Clipper’ command module and collected valuable science data from overhead.

On the anniversary of the lunar landing, the rover science team decided to honor the Apollo 12 mission as Opportunity was driving east and chanced upon a field of small impact craters located in between vast Martian dune fields. Informal crater names are assigned by the team to craters spotted by Opportunity in the Meridiani Planum region based on the names of historic ships of exploration.

Opportunity rover took first panorama of Intrepid crater on Sol 2417 (Nov.11, 2010) which shows the rim of distant Endeavour crater in the background. Mosaic Credit: NASA/JPL/Cornell

Rover science team member James Rice, of NASA’s Goddard Space Flight Center, Greenbelt, Md., suggested using names from Apollo 12 because of the coincidental timing according to NASA. “The Apollo missions were so inspiring when I was young, I remember all the dates. When we were approaching these craters, I realized we were getting close to the Nov. 19 anniversary for Apollo 12,” Rice said. He sent Bean and Gordon photographs that Opportunity took of the two craters named for the two Apollo 12 spaceships.

Bean wrote back the following message to the Mars Exploration Rover team: “I just talked with Dick Gordon about the wonderful honor you have bestowed upon our Apollo 12 spacecraft. Forty-one years ago today, we were approaching the moon in Yankee Clipper with Intrepid in tow. We were excited to have the opportunity to perform some important exploration of a place in the universe other than planet Earth where humans had not gone before. We were anxious to give it our best effort. You and your team have that same opportunity. Give it your best effort.”

On November 4, Opportunity drove by and imaged ‘Yankee Clipper’ crater. After driving several more days she reached ‘Intrepid’ on November 9. The rover then traversed around the crater rim and photographed the crater interior from different vantage points, collecting two panoramic views along the way.

The rover team assembled the initial tribute panoramic mosaic taken on Sol 2417 (Nov. 11) and which can be seen here in high resolution along with ‘Yankee Clipper’.

Opportunity soon departed Intrepid on Sol 2420 (Nov. 14) to resume her multi-year trek eastwards and took a series of crater images that day – from a very different direction – which we were inspired to assemble into a panoramic mosaic (in false color) in tribute to the Apollo 12 mission (see above).

Our mosaic tribute clearly shows the rover wheel tracks as Opportunity first approached Intrepid on Nov. 9 – which is fittingly reminiscent of the Apollo 12 astronauts walking on the moon 41 years ago as they explored a lunar crater. By comparison, the arrival mosaic from Sol 2417 shows distant Endeavour crater in the background.

Intrepid crater is about 16 meters in diameter, thus similar in size to ‘Eagle’ crater inside which Opportunity first landed on 24 January 2004 after a 250 million mile ‘hole in one shot’ from Earth. Eagle was named in honor of the Apollo 11 mission.

“Intrepid is fairly eroded with sand filling the interior and ejecta blocks planed off by the saltating sand”, said Matt Golembek, Mars Exploration Program Landing Site Scientist at the Jet Propulsion Laboratory (JPL), Pasadena, Calif. Asked about the age of Intrepid crater, Golembek told me; “Based on the erosional state it is at least several million years old, but less than around 20 million years old.”

Opportunity is blazing ahead towards a huge 22 km (14 mile) wide crater named ‘Endeavour’, which shows distinct signatures of clays and past wet environments based on orbital imagery thus making the crater a compelling science target.

“Intrepid is 1.5 km from Santa Maria crater and about 7.5 km from Endeavour.”

“We should be at Santa Maria crater next week, where we will spend the holidays and conjunction. Then it will be 6 km to Endeavour,” Golembek said.

The road ahead looks to be alot friendlier to the intrepid rover. “The terrain Opportunity is on is among the smoothest and easiest to traverse since Eagle and Endurance. Should be smooth sailing to Endeavour, averaging about 100 meters per drive sol. We should easily beat MSL to the phyllosilicates,” Golembek explained.

Phyllosilicates are clay minerals that form under wet, warm, non-acidic conditions. They have never before been studied on the Martian surface.

MSL is the Mars Science Lab, NASA’s next Mars lander mission and which is scheduled to blast off towards the end of 2011. Golembek leads the landing site selection team.

The amazing Opportunity rover has spent nearly seven years roving the Martian surface, conducting a crater tour during her very unexpectedly long journey at ‘Meridiani Planum’ on Mars which now exceeds 26 km (16 miles). The rovers were designed with a prime mission “warranty” of just 90 Martian days – or sols – and have vastly exceeded their creators expectations.

“What a ride. This still does not seem real,” Rob Manning told me. Manning headed the Entry, Descent and Landing team at JPL for both the Spirit and Opportunity rovers. “That would be fantastic if Opportunity could get to the phyllosilicates before MSL launches.”

Stay tuned.

This map of the region around NASA's Mars Exploration Rover Opportunity shows the relative locations of several craters and the rover location in May 2010. Credit: NASA/JPL-Caltech/Malin Space Science Systems/WUSTL
AS12-48-7133 (20 Nov. 1969) --- This unusual photograph, taken during the second Apollo 12 extravehicular activity (EVA), shows two U.S. spacecraft on the surface of the moon. The Apollo 12 Lunar Module (LM) is in the background. The unmanned Surveyor 3 spacecraft is in the foreground. The Apollo 12 LM, with astronauts Charles Conrad Jr. and Alan L. Bean aboard, landed about 600 feet from Surveyor 3 in the Ocean of Storms. The television camera and several other pieces were taken from Surveyor 3 and brought back to Earth for scientific examination. Here, Conrad examines the Surveyor's TV camera prior to detaching it. Astronaut Richard F. Gordon Jr. remained with the Apollo 12 Command and Service Modules (CSM) in lunar orbit while Conrad and Bean descended in the LM to explore the moon. Surveyor 3 soft-landed on the moon on April 19, 1967.
Posted on by Mike Simonsen

Venus Has a Moon?

Venusian quasi-satellite 2002 VE68. Illustration: NASA/JPL/Caltech

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Astronomers have been busy trying to determine the spin period and composition of Venus’ moon. December 8, 2010, results were announced by JPL/Caltech scientists, led by Michael Hicks.

“Wait a minute; back up”, I hear you ask. “Venus has a Moon?”
Of course it does. Well, kind of…
Let me explain.

It has the rather unfortunate name of 2002 VE68. That is because it was discovered on November 11, 2002 by LONEOS, the Lowell Observatory Near Earth Object Search. 2002 VE68 is an earth orbit-crossing asteroid that has been designated a Potential Hazardous Asteroid by the Minor Planet Center. For obvious reasons, this makes it a very interesting subject of study for JPL scientists.

2002 VE68 used to be a run of the mill, potential impact threat, Near Earth Object. But approximately 7000 years ago it had a close encounter with Earth that kicked it into a new orbit. It now occupies a place in orbit around the Sun where at its closest it wanders inside the orbit of Mercury and at its furthest it reaches just outside the orbit of the Earth. It is now in a 1:1 orbital resonance with Venus.

An orbital resonance is when two orbiting bodies exert a regular, periodic gravitational influence on each other due to their orbital periods being related by a ratio of two small numbers. For example, Pluto and Neptune are in an orbital resonance of 2:3, which simply means for every two times Pluto goes around the Sun, Neptune makes three trips around.

In the case of Venus and 2002 VE68, they both take the same time to orbit the Sun once. They are in a 1:1 orbital resonance. So by definition, 2002 VE68 is considered a quasi-satellite of Venus. If you watch the Orbital Viewer applet at the JPL small body page you can watch this celestial dance as the two bodies orbit the Sun and each other as 2002 VE68 dodges Earth and Mercury in the process.

Often these resonances result in an unstable interaction, in which the bodies exchange momentum and shift orbits until the resonance no longer exists. In this case, scientists believe 2002 VE68 will only remain a Venusian quasi-satellite for another 500 years or so.

So getting back to the story, Hicks and his team used the recent close apparition of 2002 VE68 to do photometric measurements over the course of three nights in November using the JPL Table Mountain 0.6m telescope near Wrightwood, California. From the color data they obtained they determined that 2002 VE68 is an X type asteroid. This is a group of asteroids with very similar spectra that could potentially have a variety of compositions. They are further broken down into Tholen classification types as either E, M or P types. Unfortunately Hicks’ team was not able to resolve the sub-classification with their equipment.

They were able to determine the approximate size of the asteroid to be 200 meters in diameter, based on its absolute magnitude, and they determined a spin rate of 13.5 hours. The amplitude of the fluctuation on the light curve of 2002 VE68 could imply hat it is actually a contact binary, two clumps of asteroidal material orbiting a center of mass in contact with each other.

For more information on some of the strange and curious beasts in the asteroidal zoo, visit the NASA Near Earth Object Program website.

Posted on by Jerry Coffey

How Big Is Neptune

Are There Oceans on Neptune
Neptune is more than just the 8th planet in our solar system; it is a celestial reminder of the power that mathematics grants us.

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There are many ways to determine ‘how big is Neptune’. It has an equatorial radius 24,764 km, a polar radius of 24,341 km, and a surface area of 7.6408×10,sup>9km2. It has a volume of 6.254×1013km3, a mass of 1.0243×1026kg, and a mean density of 1.638 g/cm3. Now that you know most of the planet’s critical digits, here is a little information about its make up.

Neptune is the eighth and farthest planet from the Sun. It is the fourth-largest planet by diameter and the third-largest by mass. Neptune’s mass is 17 times that of the Earth. On average, Neptune orbits the Sun at a distance of 30.1 astronomical units. It was discovered on September 23, 1846. Neptune was the first planet found by mathematical prediction rather than direct observation. Alexis Bouvard deduced its existence from gravitational perturbations in the orbit of Uranus. The planet was later observed by Johann Galle. Its largest moon, Triton, was observed a short time later.

Neptune’s atmosphere is composed primarily of hydrogen and helium along with traces of hydrocarbons and nitrogen. It also contains a high proportion of ices like: water, ammonia, and methane. Astronomers occasionally categorize Neptune as an ice giant. The interior of Neptune, like that of Uranus, is primarily composed of ices and rock. Traces of methane in the outermost regions in part account for the planet’s blue appearance. Neptune’s atmosphere is notable for its active and visible weather patterns. When Voyager 2 flew by the planet’s southern hemisphere possessed a Great Dark Spot. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 km/h.Because of its great distance from the Sun, Neptune’s outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching ?218°C. Temperatures at the planet’s center are approximately 5,000°C.

Neptune has a planetary ring system. The rings may consist of ice particles coated with silicates or carbon-based material, which gives them a reddish hue. The three main rings are the narrow Adams Ring, 63,000 km from the center of Neptune, the Le Verrier Ring, at 53,000 km, and the broader, fainter Galle Ring, at 42,000 km. A faint outward extension to the Le Verrier Ring has been named Lassell; it is bounded at its outer edge by the Arago Ring at 57,000 km. Not only is the planet large, but it has many interesting features as well.

We have written many articles about Neptune for Universe Today. Here’s an article about the color of Neptune, and here are some pictures of Neptune.

If you’d like more information on Neptune, take a look at Hubblesite’s News Releases about Neptune, and here’s a link to NASA’s Solar System Exploration Guide to Neptune.

We’ve also recorded an entire episode of Astronomy Cast all about Neptune. Listen here, Episode 63: Neptune.

Source: NASA

Posted on by Nancy Atkinson

Mysterious Ribbon at Edge of Solar System is Changing

A year ago, researchers from the IBEX mission – NASA’s Interstellar Boundary Explorer – announced the discovery of an unexpected bright band or ribbon of surprisingly high energy emissions at the boundary between our solar system and interstellar space. Now, after a year of observations, scientists have seen vast changes, including an unusual knot in the ribbon which appears to have ‘untied.’ Changes in the ribbon — a ‘disturbance in the force,’ so to speak, along with a shrunken heliosphere, may be allowing galactic cosmic rays to leak into our solar system.
Continue reading “Mysterious Ribbon at Edge of Solar System is Changing”

Posted on by Tega Jessa

What Galaxy Do We Live In?

Artist's impression of The Milky Way Galaxy. Based on current estimates and exoplanet data, it is believed that there could be tens of billions of habitable planets out there. Credit: NASA

If you are not an astronomy enthusiast you not have thought much about what galaxy do we live in. So depending on that the answer may surprise you. If you know anything about galaxies you know that they are groupings of stars that number in the hundreds of billions. The most famous is the Milky Way. It is from this galaxy that we even have the term. The simple point is that the Earth is part of the Milky Way even though if we see it in the sky it looks like we are observing it from the outside. Why is that? To understand you need to know exactly where we live in neighborhood of the Milky Way Galaxy.

As we are part of the solar system Earth pretty much follows the path of the sun as it goes through its own orbit around the galaxy. The Milky Way is a spiral galaxy type so it has arms sort of like an octopus. The Sun is located near the outward tip of the Sagittarius arm of the Milky Way. This makes Earth about 28,000 light years from the galactic core of our home galaxy.

The Solar System also has a galactic year that it follows. It takes around 200 million to 250 million years for the solar system to orbit the Sun. Another indicator of our position is where the galactic equator. While our star system is considered to be on the outskirts of the Milky Way this is only an estimate. It is believed that the Milky Way is larger than first estimated. There is also suspicion that our galaxy is in the process of absorbing other smaller galaxies. However, there is not enough empirical evidence available to support the claim.

So what would be so important about knowing what part of the galaxy we live in? One reason is space exploration. Some time in the future mankind may find a way to achieve faster than light space travel. This can provide a new set of challenges for engineers and astronomers to tackle. For example how would an astronaut keep from getting lost in space? Detailed mapping and computer programming in the future could help galactic wayfarers know where they are going and more importantly how to get home.

The other reason is that it never hurts to know our place in the scheme of things. Just thinking of the challenge of finding earth if we were so far way helps us to understand how truly vast the universe is.

We have written many articles about the Milky Way galaxy for Universe Today. Here are some facts about the Milky Way, and here’s an article about the closest galaxy to the Milky Way.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We’ve also recorded an episode of Astronomy Cast about galaxies. Listen here, Episode 97: Galaxies.

Sources: SEDS, Daily Galaxy

Posted on by Nancy Atkinson

An Alien’s View of Our Solar System

We have just begun to try and image distant solar systems around other stars, and hopefully our techniques and technology will improve in the near future so that we can one day find — and take pictures of — planets as small as Earth. But what if another civilization from a distant star was looking at us? What would they see? A new supercomputer simulation tracking the interactions of thousands of dust grains show what our solar system might look like to alien astronomers searching for planets. It also provides a look back to how our planetary system may have changed and matured over time.

Continue reading “An Alien’s View of Our Solar System”

Posted on by Nancy Atkinson

Win ‘Star Walk’ and ‘Solar Walk’ Astronomy Apps

I’ve had a couple of people excitedly show me the Star Walk astronomy app on their iPhones and ipads, and it really is great. You can hold your device up to the sky and it will show you a sky map of your exact position. Move your device around the sky, and it moves with you. It is a very high quality, dynamic and realistic stargazing guide, which — if you are a beginning or experienced astronomer — makes skywatching easy for everybody! There is also a “Solar Walk” app — which has very cool 3D images, so grab your 3D glasses to fully enjoy. See more about this app below.
Continue reading “Win ‘Star Walk’ and ‘Solar Walk’ Astronomy Apps”