Posted on by Ken Kremer

NASA’s Highly Productive LADEE Dust Explorer Probe Crashes into the Moon as Planned

NASA’s LADEE lunar orbiter will firing its main engine on Oct. 6 to enter lunar orbit in the midst of the US government shutdown. Credit: NASA

NASA’s LADEE lunar orbiting dust and atmosphere explorer probe has bitten the dust and crashed into the Moon’s surface exactly as planned following a fabulously successful and groundbreaking science mission that exceeded all expectations.

The Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft impacted the far side of the Moon sometime overnight between 12:30-1:22 a.m. EDT, Friday, April 18 (9:30 and 10:22 p.m. PDT, Thursday, April 17) according to a NASA statement.

Running low on fuel and unable to continue any further science observations, the couch sized spacecraft was intentionally plunged into the rugged lunar surface at a spot designed to keep it far away from disturbing any of the historic Apollo manned lunar landing sites or unmanned surveyors on the Moon’s near side.

LADEE_Poster_01

Mission controllers at NASA’s Ames Research Center allowed LADEE’s orbit to naturally decay following the conclusion of the probes extended mission in the final low orbit science phase.

The probe was likely smashed violently to smithereens and mostly vaporized from the heat generated upwards of several hundred degrees. Any surviving debris may be buried in shallow crater formed by the impact.

“At the time of impact, LADEE was traveling at a speed of 3,600 miles per hour – about three times the speed of a high-powered rifle bullet,” said Rick Elphic, LADEE project scientist at Ames, in a NASA statement.

“There’s nothing gentle about impact at these speeds – it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area. It will be interesting to see what kind of feature LADEE has created.”

The powerful NAC telescopic camera aboard NASA’s still orbiting Lunar Reconnaissance Orbiter (LRO) will be directed in coming months to try and photograph the impact site after engineers pinpoint the likely crash site.

LRO has already imaged LADEE while both were co-orbiting in different lunar orbits.

This dissolve animation compares the LRO image (geometrically corrected) of LADEE captured on Jan 14, 2014 with a computer-generated and labeled image of LADEE . LRO and LADEE are both NASA science spacecraft currently in orbit around the Moon. Credit: NASA/Goddard/Arizona State University

This dissolve animation compares the LRO image (geometrically corrected) of LADEE captured on Jan 14, 2014 with a computer-generated and labeled image of LADEE . LRO and LADEE are both NASA science spacecraft currently in orbit around the Moon. Credit: NASA/Goddard/Arizona State University

After completing its primary science mission in March, the already ultra low altitude of the lunar orbiting probe was reduced even further so that it was barely skimming just 2 kilometers (1 mile) above the pockmarked lunar surface.

Such a low altitude thus enabled LADEE to gather unprecedented science measurements of the Moon’s extremely tenuous atmosphere and dust particles since the species would be present at a higher concentration.

Lots of fuel is required to maintain LADEE’s orbit due to the uneven nature of the Moon’s global gravity field.

The final engine firing was commanded on April 11 to ensure a far side impact and the safety of all the historic lunar landing sites.

“LADEE also survived the total lunar eclipse on April 14 to 15. This demonstrated the spacecraft’s ability to endure low temperatures and a drain on batteries as it, and the moon, passed through Earth’s deep shadow,” said NASA

LADEE was launched on Sept. 6, 2013 from NASA Wallops in Virginia on a science mission to investigate the composition and properties of the Moon’s pristine and extremely tenuous atmosphere, or exosphere, and untangle the mysteries of its lofted lunar dust dating back to the Apollo Moon landing era.

All those objectives and more were accomplished during its nearly half year investigating Earth’s nearest neighbor.

Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com
Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com

It entered lunar orbit on Oct. 6, 2013 amidst the ridiculous government shutdown that negatively affected a number of science missions funded across the US federal government.

The science mission duration had initially been planned to last approximately 100 days and finish with a final impact on the Moon on about March 24th.

NASA granted LADEE a month long extension since the residual rocket fuel was more than anticipated due to the expertise of LADEE’s navigation engineers and the precision of the launch atop the Orbital Sciences Minotaur V rocket and orbital insertion.

“It’s bittersweet knowing we have received the final transmission from the LADEE spacecraft after spending years building it in-house at Ames, and then being in constant contact as it circled the moon for the last several months,” said Butler Hine, LADEE project manager at Ames.

The 844 pound (383 kg) robot explorer was assembled at NASA’s Ames Research Center, Moffett Field, Calif., and is a cooperative project with NASA Goddard Spaceflight Center in Maryland.

The $280 million probe is built on a revolutionary ‘modular common spacecraft bus’, or body, that could dramatically cut the cost of exploring space and also be utilized on space probes to explore a wide variety of inviting targets in the solar system.

Stay tuned here for Ken’s continuing LADEE, Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, Mars rover and more planetary and human spaceflight news.

Ken Kremer

Full scale model of NASA’s LADEE lunar orbiter on display at the free visitor center at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Full scale model of NASA’s LADEE lunar orbiter on display at the free visitor center at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Posted on by Jason Major

Is Saturn Making a New Moon?

A 750-mile (1,200-km) -long feature spotted on Saturn's A ring by Cassini on April 15, 2013

Congratulations! It’s a baby… moon? A bright clump spotted orbiting Saturn at the outermost edge of its A ring may be a brand new moon in the process of being born, according to research recently published in the journal Icarus.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University in London, lead author of the paper. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

In images acquired with Cassini’s narrow-angle camera in 2013, a 1,200-kilometer-long, 10-kilometer-wide arc of icy material was observed traveling along the edge of the A ring. The arc is thought to be the result of gravitational perturbations caused by an as-yet unseen embedded object about a kilometer wide — possibly a miniature moon in the process of formation.

Cassini image of the 179-km-wide Janus from April 2010. Janus' gravity may have helped spur the formation of Peggy. (NASA/JPL-Caltech/SSI)
Cassini image of 179-km-wide Janus from April 2010. Janus’ gravity may have helped spur the formation of Peggy. (NASA/JPL-Caltech/SSI)

The half-mile-wide object has been unofficially named “Peggy,” after lead author Murray’s mother-in-law (whose 80th birthday it was on the day he was studying the Cassini NAC images.) Murray first announced the findings on Dec. 10, 2013 at the AGU 13 meeting in San Francisco.

According to the team’s paper, Peggy’s effects on the A ring has been visible to Cassini since May 2012.

Eventually Peggy may coalesce into a slightly larger moon and move outward, establishing its own orbital path around Saturn. This is how many of Saturn’s other moons are thought to have formed much further back in the planet’s history. Now, its rings having been depleted of moon-stuff, can only create tiny objects like Peggy.

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event.”
– Linda Spilker, Cassini Project Scientist at JPL

While it is possible that the bright perturbation is the result of an object’s breakup rather than formation, researchers are still looking forward to finding out more about its evolution.

Read more on the NASA/JPL news release here.

To find out more about the Cassini mission visit saturn.jpl.nasa.gov and www.nasa.gov/cassini. The Cassini imaging team’s website is at ciclops.org.

Posted on by Jason Major

Cassini Sees a “Zen Garden” on Titan

Radar image of rows of dunes on Titan. Credit: NASA/JPL-Caltech

Looking like the flowing designs carved by a Zen gardener’s rake, long parallel dunes of hydrocarbon sand stretch across the surface of Saturn’s moon Titan. The image above, acquired by Cassini in July 2013, reveals these intriguing and remarkably Earthlike landforms in unprecedented detail via radar, which can easily pierce through Titan’s thick clouds.

I’m feeling a little more enlightened already.

Although it piles into dunes like sand does here, Titan’s sand is not the same as what you’d find on a beach here on Earth. According to an ESA “Space in Images” article:

While our sand is composed of silicates, the ‘sand’ of these alien dunes is formed from grains of organic materials about the same size as particles of our beach sand. The small size and smoothness of these grains means that the flowing lines carved into the dunes show up as dark to the human eye.

Titan's surface is almost completely hidden from view by its thick orange "smog" (NASA/JPL-Caltech/SSI. Composite by J. Major)
Titan’s surface is almost completely hidden from view by its thick orange “smog” (NASA/JPL-Caltech/SSI. Composite by J. Major)

Radar imaging, although capable of seeing through Titan’s opaque orange atmosphere, doesn’t capture visible-light images. Instead it’s sensitive to the varying textures of a landscape as they reflect microwaves; the smoother an object or an area is the darker it appears to radar, while irregular, rugged terrain shows up radar-bright.

The pixelated “seam” cutting horizontally across the center is the result of image artifacting.

Learn more about Cassini’s RADAR instrument here, and read more about this image on the ESA site here.

Posted on by Fraser Cain

Can You Escape the Force of Gravity?

Can You Escape the Force of Gravity?

It feels like you just can’t get away from clingy gravity. Even separated by distances of hundreds of millions of light years, gravity is reaching out to all of us. Is there a place you could go to get away from gravity entirely?

Fortunately for our space intolerant tissues and terrible oxygen dependency withdrawal symptoms, gravity binds us to our sweet, cozy home with breathable air, the Earth. Its collective mass is trying to accelerate you towards its center, that way, at 9.8 meters per second squared. But the Earth isn’t the only one looking to cuddle.

You’re also being pulled at by the Moon, and if it weren’t for the Earth here, that pull could hurl you far off into deep space, or crash you into its cold dusty surface. In fact, as the Moon passes overhead, you’re being imperceptibly tugged upwards. This possessive tug o war isn’t just between the moon, and the earth fighting over you like an older brother keeping a small doll out of reach a younger sibling.

The Sun is also in on this shenanigan. Gravity from there is pulling at you from a distance of 150 million km. Well, aren’t we popular. So how far would you have to go to escape this gravitational custody battle completely?

Even At 2.5 million light years distance, gravity is still reaching out and being a clingy creeper. The Milky Way and Andromeda are pulling towards each other. The gravity between these two bodies is strong enough to overcome the expansion of the universe. Which will result in a galactic smash-up derby a few billion years from now.

There’s no end to it. Gravity appears to be madly greedy and long armed. Members of the Virgo Super cluster are connected to each other, and they’re dozens of millions of light-years apart. Objects in the Pisces-Cetus Super cluster complex are even connected to each other by our invisible and obnoxiously possessive friend. And they are hundreds of millions of light years apart…

In fact, you’re so popular that you are gravitationally pulled towards even most distant object in the observable Universe. And they, in turn, are linked to you. As a result, without the outward expansion and acceleration of the Universe, everything would fall inward to a common center of gravity. Newton thought that gravity was instantaneous and if the Sun disappeared, the Earth would immediately fly away. Einstein realized that gravity is distortions of spacetime caused by mass. And as it turns out, gravity moves at the speed of light.

Artist's impression of gravitational waves. Image credit: NASA
Artist’s impression of gravitational waves. Image credit: NASA

If the Sun disappeared, Earth would continue to follow the curved spacetime distortion for 8 whole minutes. Interactions between massive objects, like when black holes collide, cause ripples in spacetime called gravitational waves. As a gravitational wave passes through, you get warped in spacetime, like a wave in the water. The amount is so slight we’ve never seen them directly. However, the decay of pulsar orbits have shown them indirectly.

The ground-based LIGO experiment might someday detect a gravitational wave, but there’s been no luck so far. The Space-based LISA experiment should detect gravitational waves with more precision. The first version will launch in 2015, but the real experiment probably won’t be operational until 2030.

Everybody wants a piece, and I don’t know about you, I just want to be left alone. Gravity’s is reach is amazingly far. It’s everywhere, all the time, and it’s having none of that. What do you think? If you had the power to remove yourself from Gravity’s pull, what would you do? Tell us in the comments below.

Posted on by Ken Kremer

NASA Announces ‘Take the Plunge’ Contest – Guess when LADEE Hits the Moon – Soon!

You can enter NASA’s ‘Take the Plunge’ contest and guess LADEE’s impending lunar impact date, expected on or before April 21, 2014. Credit: NASA

You can enter NASA’s ‘Take the Plunge’ contest and guess LADEE’s impending lunar impact date, expected on or before April 21, 2014. Credit: NASA
Contest entry details below – deadline soon[/caption]

When will LADEE hit the Moon for its looming end of mission finale?

NASA’s resoundingly successful LADEE lunar dust exploring mission is nearly out of gas – and needs your help, now!

With its inevitable doom approaching, NASA needs you to summon your thoughts and is challenging you to participate in a ‘Take the Plunge’ contest – figuratively not literally – and guess LADEE’s impending impact date.

LADEE, which stand for Lunar Atmosphere and Dust Environment Explorer, will smack violently into the Moon and scatter into zillions of bits and pieces sometime in the next two and a half weeks, on or before about April 21.

But exactly when will it impact the lunar surface? NASA wants to hear your best guess!

The ‘Take the Plunge’ contest was announced by NASA today, April 4, at a media briefing.

For more information about the challenge and how to enter, visit: http://socialforms.nasa.gov/ladee

This dissolve animation compares the LRO image (geometrically corrected) of LADEE captured on Jan 14, 2014 with a computer-generated and labeled image of LADEE . LRO and LADEE are both NASA science spacecraft currently in orbit around the Moon. Credit: NASA/Goddard/Arizona State University
This dissolve animation compares the LRO image (geometrically corrected) of LADEE captured on Jan 14, 2014 with a computer-generated and labeled image of LADEE . LRO and LADEE are both NASA science spacecraft currently in orbit around the Moon. Credit: NASA/Goddard/Arizona State University

Between now and its inevitable doom, mission controllers will command LADEE to continue gathering groundbreaking science.

And it will do so at an even lower attitude that it orbits today by firing its orbit maneuvering thrusters tonight and this weekend.

The couch sized probe seeks to eek out every last smidgeon of data about the Moons ultra tenuous dust and atmospheric environment from an ultra low altitude just a few miles (km) above the pockmarked lunar surface.

But because the moon’s gravity field is so uneven, the probes thrusters must be frequently fired to keep it on course and prevent premature crashes.

“The moon’s gravity field is so lumpy, and the terrain is so highly variable with crater ridges and valleys that frequent maneuvers are required or the LADEE spacecraft will impact the moon’s surface,” said Butler Hine, LADEE project manager at Ames.

“Even if we perform all maneuvers perfectly, there’s still a chance LADEE could impact the moon sometime before April 21, which is when we expect LADEE’s orbit to naturally decay after using all the fuel onboard.”

LADEE will fly as low as fly approximately 1 to 2 miles (2 to 3 kilometers) above the surface.

Everyone of all ages is eligible to enter NASA’s “Take the Plunge: LADEE Impact Challenge.”

The submissions deadline is 3 p.m. PDT Friday, April 11.

NASA says that winners post impact. They will receive a commemorative, personalized certificate from the LADEE program via email.

Series of LADEE star tracker images features the lunar terrain. Credit: NASA Ames
Series of LADEE star tracker images features the lunar terrain. Credit: NASA Ames

Watch for my upcoming story on LADEE’s science accomplishments and what’s planned for her final days.

LADEE was launched on Sept. 6, 2013 from NASA Wallops in Virginia on a science mission to investigate the composition and properties of the Moon’s pristine and extremely tenuous atmosphere, or exosphere, and untangle the mysteries of its lofted lunar dust dating back to the Apollo Moon landing era.

Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com
Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com

The science mission duration had initially been planned to last approximately 100 days and finish with a final impact on the Moon on about March 24th.

NASA granted LADEE a month long extension since the residual rocket fuel is more than anticipated due to the expertise of LADEE’s navigation engineers and the precision of the launch atop the Orbital Sciences Minotaur V rocket and orbital insertion.

Stay tuned here for Ken’s continuing LADEE, Chang’e-3, Orion, Orbital Sciences, SpaceX, commercial space, Mars rover and more planetary and human spaceflight news.

Learn more at Ken’s upcoming presentations at the NEAF astro/space convention, NY on April 12/13 and at Washington Crossing State Park, NJ on April 6.

Ken Kremer

Full scale model of NASA’s LADEE lunar orbiter on display at the free visitor center at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Full scale model of NASA’s LADEE lunar orbiter on display at the free visitor center at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer.com
Posted on by David Dickinson

Observing Alert: Watch the Moon Cross the Hyades This Week

(Credit Tavi)

A photogenic grouping greets evening sky watchers this week providing a fine teaser leading up to a spectacular eclipse.

On the evening of Thursday, April 3rd headed into the morning of the 4th, the waxing crescent Moon crosses in front of the Hyades open star cluster.  This is the V-shaped asterism that marks the head on Taurus the Bull, highlighted by the brilliant foreground star Aldebaran as the bull’s “eye”.  Viewers across North America will have a ring-side seat to this “bull-fight” as the 20% illuminated Moon stampedes over several members of the Hyades in its path.

Starry Night
The passage of the Moon through the Hyades over a three hour span on the night of April 3rd (April 4th in Universal Time) comparing the North American locales of Tampa, Florida and Seattle, Washington. (Credit: Starry Night Education Software).

The brightest stars to be occulted are the Delta Tauri trio of stars ranging in magnitudes from +3.8 (Delta Tauri^1) to +4.8(2) and +4.3(3). Such occlusions – known in astronomy as occultations – are fun to watch, and can reveal the existence of close binary companions as they wink out behind the lunar limb. Several dozen occultations of stars brighter than +5th magnitude by the Moon happen each year, and the best events occur when the Moon is waxing and the stars disappear against its dark leading edge. We recently caught one such event last month when the Moon occulted the bright star Lambda Geminorum:

We are currently seeing the Moon cross the Hyades during every lunation until the year 2020, though it’s a particularly favorable time to catch the event in April 2014 as the Moon is a slender crescent. Notice that you can just make out the dark limb of the Moon with the naked eye? What you’re seeing is termed Earthshine, and that’s just what it is: the nighttime side of the Moon being illuminated by sunlight that is reflected off of the Earth. Standing on the Earthward side of the Moon, an observer would see a waning gibbous Earth about two degrees across. Yutu has a great view!

Credit Occult 4.0
The occultation footprint for Delta Tauri^1. Credit: Occult 4.0

The Moon will cross its descending node where its apparent path intersects the ecliptic on April 1st (no joke, we swear) at 2:30 Universal Time or 10:30 PM EDT on March 31st. The next nodal crossing now occurs in just two weeks, and the Earth’s shadow will be there to greet the Moon on the morning of April 15th in the first of four total lunar eclipses that span 2014 and 2015. The month of April also sees the Moon’s orbit at its least eccentric, a time at which perigee – the Moon’s closest point to Earth – is at its most distant and apogee – its farthest point – is at its closest. This currently happens near the equinoxes, through the nodes slowly travel across the ecliptic completing one revolution every 18.6 years. Perigee can vary from 356,400 to 370,400 kilometres, and apogee can span a distance from 404,000 to 406,700 kilometres.

Stellarium
Looking west from the US SE at about 10PM local on the evening of April 3rd. Credit: Stellarium.

We’re also headed towards a “shallow year” in 2015 when the Moon has the least variability in respect to its declination. This trend will then reverse, climaxing with a “Long Nights Moon” riding high in the sky in 2025, which last occurred in 2006. The Moon will inch ever closer to Aldebaran on every successive lunation now, and begins a series of occultations of Aldebaran on January 29th, 2015 through the end of 2018. Occultations of Aldebaran always occur near these shallow years, and will be followed by a cycle of occultations of Regulus starting in 2017. We caught an excellent daytime occultation of Aldebaran by the Moon from North Pole, Alaska during the last cycle in the late 1990s.

Photos by Author
The Moon passing between the Hyades and Pleiades in 2011 with Earthshine highlighted. Photos by author.

Now for the wow factor. Our Moon is 3,474 kilometres across and located just over one light second away. The Hyades star cluster covers about 6 ½ degrees of sky – about 7 times the size of the Full Moon – but is the closest open cluster to the Earth at 153 light years distant and has a core diameter of about 18 light years across. As mentioned previous, Aldebaran isn’t physically associated with the Hyades, but is merely located in the same direction at 65 light years distant.

The Hyades star cluster also provided early 20th astronomers with an excellent study in galactic motion. At an estimated 625 million years in age, the Hyades are slowly getting disbanded and strewn about the Milky Way galaxy in a process known as evaporation. The Hyades are also part of a larger stellar incorporation known as the Taurus Moving Cluster. Moving at an average of about 43 kilometres a second, the members of the Hyades are receding from us towards a divergent point near the bright star Betelgeuse in the shoulder of Orion. 50 million years hence, the Hyades will be invisible to the naked eye as seen from Earth, looking like a non-descript open cluster and providing a much smaller target for the Moon to occult at 20’ across. Astronomer Lewis Boss was the first to plot the motion of the Hyades through space in 1908, and the cluster stands as an essential rung on the cosmic distance ladder, with agreeing measurements independently made by both Hubble and Hipparcos and soon to be refined by Gaia.

Photographing and documenting this week’s passage of our Moon across the Hyades is easy with a DSLR camera: don’t be afraid to vary those ISO and shutter speeds to get the mix of the brilliant crescent Moon, the fainter earthshine, and background stars just right. The more adventurous might want to try actually catching the numerous occultations of bright stars on video. And U.S. and Canadian west coast observers are well placed to catch the Moon cross right though the core of the Hyades… a video animation of the event is not out of the question!

And from there, the Moon heads on to its date with destiny and a fine total lunar eclipse on April 15th which favors North American longitudes. We’ll be back later this week with our complete and comprehensive eclipse guide!