Satellites Archives

October 24, 2013March 16, 2017 by Fraser Cain

How Many Satellites are in Space?

The space age began on October 4, 1957 with the launch of the first artificial satellite, Sputnik 1. This tiny spacecraft lasted only three months in orbit, finally burning up in the Earth’s atmosphere.

Following in these historic footsteps, many more spacecraft have been sent into Earth’s orbit, around the Moon, the Sun, the other planets, and even out of the Solar System itself. At the time that I’m recording this video, there are 1071 operational satellites in orbit around the Earth. 50 percent of which were launched by the United States.

Half of that 1071 are in Low-Earth Orbit, just a few hundred kilometers above the surface. Some of the most notable of these include the International Space Station, the Hubble Space Telescope, and many Earth observation satellites.

About a twentieth are in Medium-Earth Orbit, around 20,000 kilometers up, which are generally global positioning satellites used for navigation. A small handful are in elliptical orbits, where their orbit brings them closer and further to the Earth.
The rest are in geostationary orbit, at an altitude of almost 36,000 kilometers.

If we could see these satellites from Earth’s surface, they would appear to hang motionless in the sky. The fact that they remain over the geographic same area means they provide the perfect platform for telecommunications, broadcast or weather observations.

But there are many, many more artificial objects orbiting the Earth. In this collection of space debris we’re talking spent boosters, dead satellites, and even misplaced gloves. According to the United States Space Surveillance Network, there are more than 21,000 objects larger than 10 cm orbiting the Earth. Just a small fraction of these are operational satellites. It’s estimated there are a further 500,000 bits and pieces between 1 and 10 cm in size.

Near Earth orbit is so polluted with junk that the International Space Station is often moved to avoid impact with dangerous chunks of space debris. Many of these objects are created through collisions, and some scientists are worried that future space travel might be too risky if we get too much junk orbiting the planet. We might seal ourselves inside a shield of shrieking metal moving at 29,000 km/hour.

Looking outwards from our own orbit, at any time there are a handful of satellites orbiting the Moon. Right now, NASA’s Lunar Reconnaissance Orbiter and Lunar Atmosphere and Dust Environment Explorer are in lunar orbit. Further still, there’s 1 spacecraft around Mercury, 1 at Venus, 3 visiting Mars and 1 orbiting Saturn. There’s a handful of spacecraft orbiting the Sun, although they’re leading or trailing the Earth in its orbit. And a few spacecraft are on trajectories to take them out of the Solar System entirely. NASA’s Voyager spacecraft, exited the Sun’s heliosphere in 2013, and entered the interstellar medium.

Starting with Sputnik’s lonely journey over 50 years ago, It’s amazing to consider just how many satellites we’ve already launched into space in just a few decades. With more launches all the time, space is becoming a busy place, with so many exciting missions to look forward to.

We have written many articles about satellites for Universe Today. Here’s an article about two satellites that collided in Earth orbit, and here are some pictures of satellites.

You can learn more about the US Space Surveillance Network from the United States Strategic Command website.

We have also recorded a whole episode of Astronomy Cast about space junk. Listen here, Episode 82: Space Junk.

October 8, 2013December 23, 2015 by David Dickinson

A Tale of a Lost Moon: Hubble Spies Neptune’s Moons and Its Rings

Neptune's system of moons and rings visualized. Credit: SETI

“That’s no moon…”

-B. Kenobi

But in this case, it is… a lost moon of Neptune not seen since its discovery in the late 1980’s.

A new announcement from the 45^th Meeting of the Division for Planetary Sciences of the American Astronomical Society being held this week in Denver, Colorado revealed the recovery of a moon of Neptune that was only briefly glimpsed during the 1989 flyby of Voyager 2.

The re-discovery Naiad, the innermost moon of Neptune, was done by applying new processing techniques to archival Hubble images and was announced today by Mark Showalter of the SETI institute.

Collaborators on the project included Robert French, also from the SETI Institute, Dr. Imke de Pater of UC Berkeley, and Dr. Jack Lissauer of the NASA Ames Research Center.

The findings were a tour-de-force of new techniques applied to old imagery, and combined the ground-based 10 meter Keck telescope in Hawaii as well as Hubble imagery stretching back to December 2004.

The chief difficulty in recovering the diminutive moon was its relative faintness and proximity to the “dazzling” disk of Neptune. At roughly 100 kilometres in diameter and an apparent magnitude of +23.9, Naiad is over a million times fainter than +8th magnitude Neptune. It’s also the innermost of Neptune’s 14 known moons, and orbits once every 7 hours just 23,500 kilometres above the planet’s cloud tops. Neptune itself is about 49,000 kilometres in diameter, and only appears 2.3” in size from Earth. From our Earthly vantage point, Naiad only strays about arc second from the disk of Neptune, a tiny separation.

“Naiad has been an elusive target ever since Voyager left the Neptune system,” Showalter said in a recent SETI Institute press release. Voyager 2 has, to date, been the only mission to explore Uranus and Neptune.

To catch sight of the elusive inner moon, Showalter and team applied new analyzing techniques which filtered for glare and image artifacts that tend to “spill over” from behind the artificially occulted disk of Neptune.

Other moons, such as Galatea and Thalassa — which were also discovered during the 1989 Voyager 2 flyby — are also seen in the new images. In fact, the technique was also used to uncover the as of yet unnamed moon of Neptune, S/2004 N1 which was revealed earlier this year.

Naiad is named after the band of nymphs in Greek mythology who inhabited freshwater streams and ponds. The Naiads differed from the saltwater-loving Nereids of mythology fame, after which another moon of Neptune discovered by Gerard Kuiper in 1949 was named.

It’s also intriguing to note that Naiad was discovered in a significantly different position in its orbit than expected. Clearly, its motion is complex due to its interactions with Neptune’s other moons.

“We don’t quite have enough observations to establish a refined orbit,” Mr. Showalter told Universe Today, noting that there may still be some tantalizing clues waiting to be uncovered from the data.

I know the burning question you have, and we had as well during the initial announcement today. Is it REALLY Naiad, or another unknown moon? Showalter notes that this possibility is unlikely, as both objects seen in the Hubble and Voyager data are the same brightness and moving in the same orbit. To invoke Occam’s razor, the simplest solution— that both sightings are one in the same object —is the most likely.

“Naiad is well inside Neptune’s Roche Limit, like many moons in the solar system,” Mr. Showalter also told Universe Today. Naiad is also well below synchronous orbit, and is likely subject to tidal deceleration and may one day become a shiny new ring about the planet.

The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into a equivalent 95 minute exposure, and the ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute). — The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into an equivalent 95 minute exposure. The ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute).

And speaking of which, the tenuous rings of Neptune have also evolved noticeably since the 1989 Voyager flyby. First discovered from the ESO La Silla Observatory in 1984, data using the new techniques show that the knotted ring segments named the Adams and Le Verrier have been fading noticeably.

“In a decade or two, we may see an ‘arc-less’ ring,” Showalter noted during today’s Division for Planetary Sciences press conference. The two ring segments observed are named after Urbain Le Verrier and John Couch Adams, who both calculated the position of Neptune due to orbital perturbations of the position of Uranus. Le Verrier beat Adams to the punch, and Neptune was first sighted from the Berlin Observatory on the night of September 23^rd, 1846. Observers of the day were lucky that both planets had undergone a close passage just decades prior, or Neptune may have gone unnoticed for considerably longer.

The rings of Neptune as seen from Voyager 2 during the 1989 flyby. (Credit: NASA/JPL).

Neptune has completed just over one 164.8 year orbit since its discovery. It also just passed opposition this summer, and is currently a fine telescopic object in the constellation Aquarius.

Unfortunately, there aren’t any plans for a dedicated Neptune mission in the future. New Horizons will cross the orbit of Neptune in August 2014, though it’s headed in the direction of Pluto, which is currently in northern Sagittarius. New Horizons was launched in early 2006, which gives you some idea of just how long a “Neptune Orbiter” would take to reach the outermost ice giant, given today’s technology.

This represents the first time that Naiad has been imaged from the vicinity of Earth, and demonstrates a new processing technique capable of revealing new objects in old Hubble data.

“We keep discovering new ways to push the limit of what information can be gleaned from Hubble’s vast collection of planetary images,” Showalter said in the SETI press release.

Congrats to Showalter and team on the exciting recovery… what other moons, both old and new, lurk in the archives waiting to be uncovered?

– Read today’s SETI Institute press release on the recovery of Naiad.

-Be sure to follow all the action at the 45th DPS conference in Denver this week!

October 3, 2013December 23, 2015 by David Dickinson

Is Iran REALLY Planning on Sending a Cat Into Space?

“I’m going where?”

No, this isn’t The Onion… as a concerned consumer of all that is space news, you have indeed arrived at the cyber-doorstep of Universe Today.

I’ll admit though, that we did do a double take about a week back when a peculiar claim came our way via the Iranian Space Agency. Yes, there is an Iranian Space Agency, and it’s kind of frightening that they remain open for business while NASA is largely shutdown.

In mid-September, senior Iranian space program official Mohammad Ebrahimi issued a statement that Iran will attempt another bio-capsule launch “within 45 days”. The unwilling occupant: a Persian cat.

Apparently, a rabbit, a mouse, and another “Space Monkey” were also in the running. Iran’s space program is shrouded in secrecy, and most launches are only announced after they’ve been conducted. This is a convenient political strategy for hiding launch failures that harkens back to the early days of the Cold War. You’re right in guessing that the Iranian Space Agency probably won’t hold a Tweetup for this one. Many western analysts see the Iran’s space effort as a thinly veiled attempt to develop its long range ballistic missile technology. Along with Israel, Iran remains the only Middle Eastern country with the proven technology to conduct indigenous satellite launches.

Iran has stated that it hopes to put an astronaut in orbit by 2019. The Pishgam (or “Pioneer” in Farsi) 2 bio-capsule launch could occur from a mobile launcher at Semnan Space Center as early as October 15^th. Satellite sleuths are also expecting activity at Semnan to pick up this month, with the possible launch of SharifSat atop a Safir 1-B rocket, and Iran’s Toulou satellite aboard a rumored new launch vehicle.

Iran successfully became a space-faring nation with the launch of its 27 kilogram Omid satellite on February 2^nd, 2009. It isn’t immediately clear if the upcoming launch will be an orbital launch or a sub-orbital ballistic shot. If Pisgam-2 achieves orbit, said “Space Cat” would become the first feline to circle the Earth. If recovery is attempted —again, Iran is always nebulous as to their intentions— it would also be the first time they’ve achieved a return from orbit.

But is “Space Cat” even a reality?

Iran has been caught red-handed before playing a shell game with the media in terms of its space program. Earlier this year, “Monkey-gate” erupted, as before-and-after images from the Pisgam-1 bio-capsule suborbital launch clearly showed two different monkeys before and after the flight:

Monkey business? Iran displayed a decidedly different looking monkey before, during, and after launch earlier this year! (Credit: Iran News Agency).

Clearly, Iran and other ‘Axis of Evil’ countries definitely need to sharpen their Photoshop, or at least their monkey-switching skills. Either said monkey launch never actually occurred, or (more likely), the unwilling Iranian space primate never survived the flight.

Perhaps this is why Iran decided on a feline occupant this time around, for possible ease of replacement?

PETA, the People for the Ethical Treatment of Animals, have also issued a statement concerning the impending launch of “Space Cat” by Iran, calling the action an “archaic experiment, a throwback to the primitive techniques of the 1950’s.”

NASA did entertain the idea of "Catronauts" early in the space program. (Credit: NASA). — NASA did entertain the idea of “Catronauts” early in the space program. (Credit: NASA).

The U.S. and the Soviet Union launched animals into space as a prelude to human spaceflight. On November 3^rd, 1957, Laika the dog became the first animal to orbit the Earth. Laika perished is space due to overheating, as did several unfortunate monkeys that were launched on the first US ballistic tests.

Russia still conducts the occasional launch of animals into space, including the Bion-1M “Space Zoo” mission earlier this year. The Bion missions allow for scientists to dissect the specimens afterwards to study the effects of a month in zero-g, something you can’t do with humans.

And the U.S. did once fly cats in zero-g aboard its Convair C-131 “Vomit Comet” aircraft, as can be seen in this bizarre video:

But the first cat in space was actually launched by France atop a Veronique AGI sub-orbital rocket 50 years ago this month on October 18^th, 1963. It would be ironic if Iran conducted it launch this month on the anniversary! The story goes the Felix, the original cat slated for the flight, escaped just prior to launch from the Sahara desert Hammaguir test site in Algeria, and was replaced by the “backup crew,” a female cat named Felicette. Felicette survived the 15 minute flight, reaching an apogee of 217 kilometres. A follow-up launch of a second cat six days later wasn’t so lucky.

Felicette (left) and Felix in publicity shots prior to launch. Note the cranial electrode (!) implants. (Credit: Marjorie-art Voila.net)

As always, Iran’s intentions for the future of its space program remain hidden. Their current launch capabilities remain limited, and are a far cry from being able to hoist a human into orbit anytime soon. If the launch of “Space Cat” does come to pass this month, it’ll be over protests from animal rights groups and the general public. Hey, didn’t the former Iranian president Mahmoud Ahmadinejad say earlier this year after “Monkey-Gate” that he was willing to be “The first Iranian to be sacrificed by the scientists of my country and go into space” as the first Iranian astronaut? Is he really going to let Space Cat upstage him?

Felix and Felicette where also commemorated on several African postage stamps. (Credit: Majorie-art.voila.net).

–Read a great synopsis of the history of felines in space from Heather Archulletta @Pillownaut.

October 1, 2013December 23, 2015 by Elizabeth Howell

What Does The Government Shutdown Mean For NASA?

The MAVEN missions ‘Going to Mars’ campaign invites the public to submit names and poems which will be included on a special DVD. The DVD will be adhered to the MAVEN spacecraft and launched to Mars on Nov. 18, 2013. Credit: NASA/GSFC

A forthcoming NASA launch to Mars could be in danger of losing its launch window should a shutdown in the United States federal government that began today (Oct. 1) continue for a while. That’s just one of the ways in which NASA is affected amid a lapse of funding that is affecting all government agencies and an untold number of government contractors.

Around 97% of NASA’s 18,000 employees are off the job. Twitter, Facebook, Google Plus and other social media accounts are going dark. NASA’s website is being pulled offline. NASA Television has also ceased broadcasting.

Beyond the agency’s public face, activities ranging from certain commercial crew payouts, to conference attendance, to scientific work will cease. Awards and scholarship approvals will be delayed.

“NASA will shut down almost entirely,” said President Barack Obama in a speech late Monday (Sept. 30).

In addition to the agency’s public relations activities, NASA is planning to launch the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft to Mars in November to examine the Red Planet’s atmosphere. There are all sorts of questions vexing scientists concerning that planet, with one of the most prominent ones being why the atmosphere thinned over the years.

Media reports indicate that if the shutdown is lengthy, MAVEN could miss the launch window and have to try again in 2016.

“A shutdown could delay the pre-launch processing currently under way with a possible impact to the scheduled Nov. 18 launch date,” Dwayne Brown, a NASA senior public affairs officer at NASA, told The Planetary Society in a story published yesterday (Sept. 30). The launch window extends for several weeks beyond that time, however.

The 3% of NASA employees who are deemed essential will work without pay until the situation is resolved. These are some of the things that will continue:

The International Space Station. Credit: NASA

International Space Station monitoring will be maintained, but with the bare minimum of ground crew. (NASA will cease regular updates of the astronauts’ activities during the furlough, although we presume if something urgent happened there would be an update.)
Robotic missions that are already in operation — think the Cassini spacecraft circling Saturn, or the Lunar Atmosphere and Dust Environment Explorer (LADEE) winging its way to the moon — will have small crews making sure that they are functioning properly. No scientific analysis will be conducted, though.
Certain other programs will continue if a shutdown would be detrimental to their performance. Space News reports that the much-delayed James Webb Space Telescope will be among them, as some of its instruments are undergoing cryogenic vacuum testing at the Goddard Space Flight Center.
Update, 1:09 p.m. EDT: Several missions run out of the Jet Propulsion Laboratory and Applied Physics Laboratory are running as usual for at least the next week because these facilities are running under contracted money from NASA and still have funds in the bank. According to the Planetary Society’s Emily Lakdawalla: “At JPL, that includes: Curiosity; Opportunity; Odyssey; Mars Reconnaissance Orbiter; Cassini; Dawn; Juno; Spitzer; the Voyagers; and WISE, among many others. At APL, that includes MESSENGER and New Horizons. It also includes the Deep Space Network.”

Additional Update, 2:09 p.m. EDT: The HiRISE twitter account just replied to inquiries from several space journalists that they will be “open for business” as usual, which is great news since the Mars Reconnaissance Orbiter made an audacious attempt to take images of Comet ISON during the comet’s closest approach to Mars today. We’ll provide any news and updates on images as they become available, but the HiRISE team said getting the images back to Earth and processing them may take a day or two.

HiRISE is still open for business and updates will continue as usual.

— HiRISE (@HiRISE) October 1, 2013

Many observers noted that NASA is marking its 55th anniversary today by shutting down its activities. There’s no word yet on when the deadlock in Congress will be resolved. The last two shutdowns in 1995 and 1996 (which began in the middle of the STS-74 shuttle mission to Mir) lasted several weeks.

September 18, 2013April 26, 2016 by Nancy Atkinson

Advanced Satellite Blasts Off from Cape Canaveral: Launch Gallery

A United Launch Alliancee Atlas V rocet lifts off with the US Air Force’s third Advanced EHF satellite. Credit and copyright: John O’Connor/nasatech.net.

Early this morning a United Launch Alliance Atlas V rocket blasted off from Cape Canaveral in a gorgeous pre-dawn launch, sending the third Advanced Extremely High Frequency (AEHF-3) satellite for the United States Air Force to orbit. The rocket lifted off from Launch Complex-41 at 4:10 am EDT (08:10 UTC) on Wednesday, September 18, 2013. Thanks to John O’Connor from nasatech.net for sharing his beautiful launch images with Universe Today.

This launch leads the way for a second launch today: the historic Orbital Sciences Antares commercial rocket carrying the first fully functional Cygnus commercial resupply vehicle to orbit from NASA’s Wallops Island Facility on a demonstration mission bound for the International Space Station.

The AEHF-3 will provide a state-of-the-art communications system for the US military and Department of Defense.

See more launches images below:

Awaiting its mission on Space Launch Complex 41, the Atlas 5 - 531/AEHF-3 stands ready as the weather slowly cleared. Credit and copyright: John O'Connor/nasatech.net, — Awaiting its mission on Space Launch Complex 41, the Atlas 5 – 531/AEHF-3 stands ready as the weather slowly cleared. Credit and copyright: John O’Connor/nasatech.net,

As the furious vibrations shake cascades of ice off of the liquid oxygen tank the Atlas 5-531 reaches for the sky and its supersynchronous transfer orbit. Credit and copyright: John O'Connor/nasatech.net. — As the furious vibrations shake cascades of ice off of the liquid oxygen tank the Atlas 5-531 reaches for the sky and its supersynchronous transfer orbit. Credit and copyright: John O’Connor/nasatech.net.

Halfway through the lightning wires, the Atlas 5 accelerates to its rendezvous with a supersynchronous transfer orbit. Credit and copyright: John O'Connor/nasatech.net. — Halfway through the lightning wires, the Atlas 5 accelerates to its rendezvous with a supersynchronous transfer orbit. Credit and copyright: John O’Connor/nasatech.net.

Through a cloud on its way to orbit, the Atlas 5 - 531 vehicle and it AEHF-3 payload dapple the clouds with light.... Credit and copyright: John O'Connor/nasatech.net. — Through a cloud on its way to orbit, the Atlas 5 – 531 vehicle and it AEHF-3 payload dapple the clouds with light…. Credit and copyright: John O’Connor/nasatech.net.

...and come out the top, amid the night, resplendent on a seething tower of dawn and thunder. Credit and copyright: John O'Connor/nasatech.net. — …and come out the top, amid the night, resplendent on a seething tower of dawn and thunder. Credit and copyright: John O’Connor/nasatech.net.

September 12, 2013April 26, 2016 by David Dickinson

Spotting Juno: NASA’s Jupiter-bound Spacecraft Gets a Boost from Earth on October 9th, 2013

An artist's conception of Juno's October 9th flyby of the Earth. (Credit: NASA/JPL -Caltech).

Psst! Live in South Africa and read Universe Today? Then you might just get a peak at the Juno spacecraft as it receives a boost from our fair planet on the evening of October 9^th, 2013.

Launched from Cape Canaveral Air Force Station on August 5^th, 2011 atop an Atlas 5 rocket in a 551 configuration, Jupiter-bound Juno is approaching the Earth from interior to its orbit over the next month. Its closest approach to the Earth during its October 9^th flyby will occur at 19:21 Universal Time (UT) which is 3:21 PM Eastern Daylight Saving Time. The spacecraft will pass 559 kilometres over the South Atlantic to a point 200 kilometres off of the southeastern coast of South Africa at latitude -34.2° south & longitude 34° east.

For context, this is just about 25% higher than the International Space Station orbits at an average of 415 kilometres above the Earth. The ISS is 108.5 metres across on its longest dimension, and we wouldn’t be surprised if Juno were a naked eye object for well placed observers watching from a dark sky site around Cape Town, South Africa. Especially if one of its three enormous 8.9 metre long solar panels were to catch the Sun and flare Iridium-style!

Two minutes before closest approach, Juno will experience the only eclipse of its mission, passing into the umbra of Earth’s shadow for about 20 minutes. Chris Peat at Heavens-Above also told Universe Today that observers in India are also well-placed to catch sight of Juno with binoculars after it exits the Earth’s shadow.

Juno passed its half-way mark to Jupiter last month on August 12^th when the “odometer clicked over” to 9.464 astronomical units. Juno will enter orbit around Jupiter on July 4^th, 2016. Juno will be the second spacecraft after Galileo to permanently orbit the largest planet in our solar system.

The passage of Juno through the Earth's shadow on October 9th, 2013. (Credit and Copyright: Heavens-Above, used with permission). — The passage of Juno through the Earth’s shadow on October 9th, 2013. (Credit and Copyright: Heavens-Above, used with permission).

Catching a flyby of Juno will be a unique event. Unfortunately, the bulk of the world will miss out, although you can always vicariously fly along with Juno with Eyes on the Solar System. Juno is currently moving about 7 km/s relative to the Earth, and will move slightly faster than the ISS in its apparent motion across the sky from west to east before hitting Earth’s shadow. This slingshot will give Juno a 70% boost in velocity to just under 12km/s relative to Earth, just slower than Pioneer 10’s current motion relative to the Sun of 12.1km/s.

At that speed, Juno will be back out past the Moon in about 10 hours after flyby. There’s a chance that dedicated imagers based along North American longitudes could still spy Juno later that evening.

Juno approaches the Earth from the direction of the constellation Libra and will recede from us in the direction of the constellation Perseus on the night of October 9^th.

The ground track covered by Juno as it passes by the Earth. (Credit & Copyright: Heavens-Above, used with permission).

There’s also a precedent for spotting such flybys previous. On August 18^th, 1999, NASA’s Cassini spacecraft made a flyby of the Earth at 1,171 kilometres distant, witnessed by observers based in the eastern Pacific region. Back then, a fuss had been raised about the dangers that a plutonium-powered spacecraft might posed to the Earth, should a mis-calculation occur. No such worries surround Juno, as it will be the first solar-powered spacecraft to visit the outer solar system.

And NASA wants to hear about your efforts to find and track Juno during its historic 2013 flyby of the Earth. JPL Horizons lists an ephemeris for the Juno spacecraft, which is invaluable for dedicated sky hunters. You can tailor the output for your precise location, then aim a telescope at low power at the predicted right ascension and declination at the proper time, and watch. Precise timing is crucial; I use WWV shortwave radio broadcasting out of Fort Collins, Colorado for ultra-precise time when in the field.

As of this writing, there are no plans to broadcast the passage of Juno live, though I wouldn’t be surprised if someone like Slooh decides to undertake the effort. Also, keep an eye on Heavens-Above, as they may post sighting opportunities as well. We’ll pass ‘em along if they surface!

Late Breaking: And surface they have… a page dedicated to Juno’s flyby of Earth is now up on Heavens-Above.

Juno is slated to perform a one year science mission studying the gravity and magnetic field of Jupiter as well as the polar magnetosphere of the giant planet. During this time, Juno will make 33 orbits of Jupiter to complete its primary science mission. Juno will study the environs of Jupiter from a highly inclined polar orbit, which will unfortunately preclude study of its large moons. Intense radiation is a primary hazard for spacecraft orbiting Jupiter, especially one equipped with solar panels. Juno’s core is shielded by one centimetre thick titanium walls, and it must thread Jupiter’s radiation belts while passing no closer than 4,300 kilometres above the poles on each pass. One run-in with the Io Plasma Torus would do the spacecraft in. Like Galileo, Juno will be purposely deorbited into Jupiter after its primary mission is completed in October 2017.

If you live in the right location, be sure to check out Juno as it visits the Earth, one last time. We’ll keep you posted on any live broadcasts or any further info on sighting opportunities as October 9^th draws near!

– Got pics of Juno on its flyby of the Earth? Send ’em in to Universe Today!

– You can also follow the mission on Twitter as @NASAJuno.

August 14, 2013December 23, 2015 by Nancy Atkinson

Satellite Watches Dust from Chelyabinsk Meteor Spread Around the Northern Hemisphere

Model and satellite data show that four days after the bolide explosion, the faster, higher portion of the plume (red) had snaked its way entirely around the northern hemisphere and back to Chelyabinsk, Russia. Image Credit: NASA's Goddard Space Flight Center Scientific Visualization

When a meteor weighing 10,000 metric tons exploded 22.5 km (14 miles) above Chelyabinsk, Russia on Feb. 15, 2013, the news of the event spread quickly around the world. But that’s not all that circulated around the world. The explosion also deposited hundreds of tons of dust in Earth’s stratosphere, and NASA’s Suomi NPP satellite was in the right place to be able to track the meteor plume for several months. What it saw was that the plume from the explosion spread out and wound its way entirely around the northern hemisphere within four days.

The bolide, measuring 59 feet (18 meters) across, slipped quietly into Earth’s atmosphere at 41,600 mph (18.6 kilometers per second). When the meteor hit the atmosphere, the air in front of it compressed quickly, heating up equally as quick so that it began to heat up the surface of the meteor. This created the tail of burning rock that was seen in the many videos that emerged of the event. Eventually, the space rock exploded, releasing more than 30 times the energy from the atom bomb that destroyed Hiroshima. For comparison, the ground-impacting meteor that triggered mass extinctions, including the dinosaurs, measured about 10 km (6 miles) across and released about 1 billion times the energy of the atom bomb.

Atmospheric physicist Nick Gorkavyi from Goddard Space Flight Center, who works with the Suomi satellite, had more than just a scientific interest in the event. His hometown is Chelyabinsk.

“We wanted to know if our satellite could detect the meteor dust,” said Gorkavyi, who led the study, which has been accepted for publication in the journal Geophysical Research Letters. “Indeed, we saw the formation of a new dust belt in Earth’s stratosphere, and achieved the first space-based observation of the long-term evolution of a bolide plume.”

The team said they have now made unprecedented measurements of how the dust from the meteor explosion formed a thin but cohesive and persistent stratospheric dust belt.

About 3.5 hours after the initial explosion, the Ozone Mapping Profiling Suite instrument’s Limb Profiler on the NASA-NOAA Suomi National Polar-orbiting Partnership satellite detected the plume high in the atmosphere at an altitude of about 40 km (25 miles), quickly moving east at about 300 km/h (190 mph).

The day after the explosion, the satellite detected the plume continuing its eastward flow in the jet and reaching the Aleutian Islands. Larger, heavier particles began to lose altitude and speed, while their smaller, lighter counterparts stayed aloft and retained speed – consistent with wind speed variations at the different altitudes.

By Feb. 19, four days after the explosion, the faster, higher portion of the plume had snaked its way entirely around the Northern Hemisphere and back to Chelyabinsk. But the plume’s evolution continued: At least three months later, a detectable belt of bolide dust persisted around the planet.

Gorkavyi and colleagues combined a series of satellite measurements with atmospheric models to simulate how the plume from the bolide explosion evolved as the stratospheric jet stream carried it around the Northern Hemisphere.

“Thirty years ago, we could only state that the plume was embedded in the stratospheric jet stream,” said Paul Newman, chief scientist for Goddard’s Atmospheric Science Lab. “Today, our models allow us to precisely trace the bolide and understand its evolution as it moves around the globe.”

NASA says the full implications of the study remain to be seen. Scientists have estimated that every day, about 30 metric tons of small material from space encounters Earth and is suspended high in the atmosphere. Now with the satellite technology that’s capable of more precisely measuring small atmospheric particles, scientists should be able to provide better estimates of how much cosmic dust enters Earth’s atmosphere and how this debris might influence stratospheric and mesospheric clouds.

It will also provide information on how common bolide events like the Chelyabinsk explosion might be, since many might occur over oceans or unpopulated areas.

“Now in the space age, with all of this technology, we can achieve a very different level of understanding of injection and evolution of meteor dust in atmosphere,” Gorkavyi said. “Of course, the Chelyabinsk bolide is much smaller than the ‘dinosaurs killer,’ and this is good: We have the unique opportunity to safely study a potentially very dangerous type of event.”

Source: NASA

July 29, 2013December 23, 2015 by Jason Major

30 Years of City Growth Seen From Space

China's now-industrialized Pearl River Delta, seen in October 1973 (top) and January 2003 (bottom)

Since the launch of its first satellite in 1972, the eight NASA/USGS Landsat satellites have made the longest continuous observations of Earth’s surface, providing invaluable data for research in agriculture, geology, forestry, regional planning, education, mapping, global change research, as well as important emergency response and disaster relief information. In addition, having such a long span of data allows us to easily see the expansion of human development in many areas — unprecedented before-and-after views of city growth seen from space.

These images, taken over the course of the Landsat program, illustrate the visible impact of over three decades of human development:

Chandler, Arizona imaged in 1985 (top) and 2011 (bottom.) As its economy shifted from agriculture to manufacturing and electronics, Chandler's population multiplied 8 times to over 236,000. — Chandler, Arizona imaged in 1985 (top) and 2011 (bottom.) As its economy shifted from agriculture to manufacturing and electronics, Chandler’s population multiplied 8 times to over 236,000.

The explosion of Istanbul's population from 2 to 3 million people is evident in these Landsat images, comparing 1975 to 2011. Vegetation appears red in the imaging wavelengths used here. — The explosion of Istanbul’s population from 2 to 13 million people is evident in these Landsat images, comparing 1975 to 2011. Vegetation appears red in the imaging wavelengths used here.

A few years ago one of the fastest-growing cities in the US, Las Vegas is seen here in images taken in 1984 (top) and 2011 (bottom.) The sprawling development -- as well as the decrease in water level of Lake Mead -- is evident. — A few years ago one of the fastest-growing cities in the US, Las Vegas is seen here in images taken in 1984 (top) and 2011 (bottom.) The sprawling development — as well as the decrease in water level of Lake Mead — is evident.

Some of the most dramatic -- and rapid -- changes have occurred in Dubai, whose artificial offshore islands suddenly appear between images taken in 2000 (top) and 2010 (bottom.) Once barely visible against the desert landscape, Dubai is now an international center of business, tourism, and oil production. — Some of the most dramatic — and rapid — changes have occurred in Dubai, whose palm- and continent-shaped artificial islands suddenly appear between images taken in 2000 (top) and 2010 (bottom.) Once barely visible against the desert landscape, Dubai is now an international center of business, tourism, and oil production.

See more of these images on NASA Goddard Space Flight Center’s Flickr album here.

The Landsat Program is a series of Earth-observing satellite missions jointly managed by NASA and the U.S. Geological Survey. In 1972, the launch of ERTS-1 (Earth Resources Technology Satellite, later renamed Landsat 1) started the era of a series of satellites that have since continuously acquired space-based land remote sensing data.

The latest satellite in the Landsat series, the Landsat Data Continuity Mission (LDCM) — now named Landsat 8 — was launched on February 11, 2013. Landsat 8 data is now available free to the public online here.

Read more on the USGS Landsat mission page here.

Image credits: USGS/NASA

July 23, 2013December 23, 2015 by Nancy Atkinson

What Can You Do With a Cubesat?

Three small CubeSats are deployed from the International Space Station on October 4, 2012. Credit: NASA

We’ve had several articles recently cubesats — low-cost satellites that seem to be the wave of the future. As technology becomes miniaturized, this allows for inexpensive and quick-to-build satellites. Additionally, they can tag along on launches already scheduled for other things. All this enables students and smaller companies to send equipment and experiments into space.

But the people from DIY Space Exploration say don’t let the small size of a cubesat fool you. The types of missions Cubesats can perform may surprise you and they’re becoming the satellite of choice for anyone looking for a low cost quick response option.

If you visit the DIY Space Exploration website, they have tutorials on how you can put your own cubesat together, and lots of other information. They’ve also put together a great infograhic about what all you can do with a cubesat:

Courtesy of: DIY Space Exploration

July 23, 2013December 23, 2015 by David Dickinson

Space Debris: A Tale of Two Satellites

Artist's concept of a GOES spacecraft in orbit. (Credit: NOAA.gov).

It’s sometimes tough being a satellite in Earth orbit these days.

An interesting commentary came our way recently via NASA’s Orbital Debris Program Office’s Orbital Debris Quarterly News. The article, entitled High-Speed Particle Impacts Suspected in Two Spacecraft Anomalies, highlights a growing trend in the local space environment.

The tale begins with GOES 13 located in geostationary orbit over longitude 75° West. Launched on May 24^th, 2006 atop a Delta IV rocket, GOES 13 is an integral part of the U.S. National Oceanic and Atmospheric Administration (NOAA’s) Geostationary Operational Environmental Satellite network.

The problems began when GOES-13 began to suffer an “attitude disturbance of unknown origin” on May 22^nd of this year, causing it to drift about two degrees per hour off of its required nadir (the opposite of zenith) pointing.

The anomaly was similar to a problem encountered by the NOAA 17 spacecraft on November 20^th, 2005. At the time, the anomaly was suspected to be due to a micrometeoroid impact. The Leonid meteors, which peak right around the middle of November, were a chief suspect. However, NOAA 17 suffered a second failure 18 days later, which was later traced down to a hydrazine leak from its errant thrusters.

GOES-13 has weathered hard times before. Back in December of 2006, GOES-13’s Solar X-Ray Imager suffered damage after being struck by a solar flare shortly after initial deployment. GOES-13 also began returning degraded imagery in September 2012, forcing it into backup status for Hurricane Sandy.

GOES-13 was restored to functionality last month. Current thinking is that the satellite was struck by a micrometeorite. No major meteor showers were active at the time.

Loss of a GOES satellite would place a definite strain on our weather monitoring and Earth observing capability. Begun with the launch of GOES-1 in 1975, currently six GOES satellites are in operation, including one used to relay data for PeaceSat (GOES-7) and one used as a communications relay for the South Pole research station (GOES-3).

The GOES program cost NOAA billions in cost overruns to execute. The next GOES launch is GOES-R scheduled in 2015.

But the universe seems to love coincidences.

NEE-01 Pegaso before deployment. (Credit: Wikimedia Commons image in the Public Domain).

Less than 26 hours after the GOES 13 anomaly, Ecuador’s first satellite, NEE-01 Pegaso began to have difficulties keeping a stable attitude. The event happened shortly after passage near an old Soviet rocket booster (NORAD designation 1986-058B) which launched Kosmos 1768 on August 2^nd, 1986. The U.S. Joint Space Operations Center had warned the fledgling Ecuadorian Space Agency that conjunction was imminent, but of course, there’s not much that could’ve been done to save the tiny CubeSat.

Although the main mass passed Pegaso at a safe distance, current thinking is that the discarded booster may have left a cloud of debris in its wake. Researchers have tracked small “debris clouds” around objects it orbit before- the collision of Iridium 33 and the defunct Kosmos 2251 on February 10^th, 2009 left a ring of debris in its wake, and the Chinese anti-satellite test carried out on January 11^th, 2007 showered low-Earth orbit with debris for years to come.

The loss represents a blow to Ecuador and their first bid to become a space-faring nation. Launched less than a month prior atop a Long March 2D rocket, Pegaso was a small 10 centimetre nanosatellite equipped with solar panels and dual infrared and visible Earth imaging systems.

A translation from the Ecuadorian Space Agencies site states that;

“The NEE-01 survived the crash and remains in orbit; however it has entered uncontrolled rotation due to the event.

Due to this rotation, (the satellite) cannot point its antenna correctly and stably to the Earth station and although still transmitting and running, the signal cannot be decoded. The Ecuadorian Civilian Space Agency is working tirelessly to stabilize the NEE-01 and recover the use of their signal.

The PEGASUS aired for 7 days your signal to the world via EarthCam, millions could see the Earth seen from space in real time, many for the first time, the files in those 7 days have been published after transmission.”

Ecuador plans to launch another CubeSat, NEE 02 Krysaor later in 2013. A carrier has not yet been named.

While both events suffered by the GOES-13 and NEE-01 Pegaso satellites were unrelated, they underscore problems with space junk and space environmental hazards that are occurring with a higher frequency.

Gabbard diagram displaying a sample disintegration of a Long March 4 booster in 2000. (Credit: the NASA Orbital Debris Office).

Such is the modern hazardous environment of low Earth orbit that new satellites must face. With a growing amount of debris, impact threats are becoming more common. The International Space Station must perform frequent debris avoidance maneuvers to avoid hazards, and more than once, the crew has waited out a pass in their Soyuz escape modules should immediate evacuation become necessary. Punctures from micro-meteoroids or space junk have even been seen recently on the ISS solar panel arrays.

Plans are on the drawing board to deal with space junk, involving everything from “space nets” to lasers and even more exotic ideas. Probably the most immediate solution that can be implemented is to assure new payloads have a way to “self-terminate” via de-orbit at the end of their life span. Solar sail technologies, such as NanoSailD2 launched in 2010 have already demonstrated this capability.

Expect reentries also pick up as we approach the peak of solar cycle #24 at the end of 2013 and the beginning of 2014. Increased solar activity energizes the upper atmosphere and creates increased drag on low Earth satellites.

It’s a brave new world “up there,” and hazards, both natural and man-made, are something that space faring nations will have to come to terms with.

-Read and subscribe to the latest edition of NASA’s Orbital Debris Quarterly News for free here.