Universe Today

July 13, 2013December 23, 2015 by Ken Kremer

Sierra Nevada Dream Chaser Gets Wings and Tail, Starts Ground Testing

Sierra Nevada Corporation’s Dream Chaser successfully rolls through two tow tests at NASA’s Dryden Flight Research Center in California in preparation for future flight testing later this year.
Watch way cool Dream Chaser assembly video below![/caption]

Sierra Nevada Corporation’s winged Dream Chaser engineering test article is moving forward with a series of ground tests at NASA’s Dryden Flight Research Center in California that will soon lead to dramatic aerial flight tests throughout 2013.

Pathfinding tow tests on Dryden’s concrete runway aim to validate the performance of the vehicles’ nose skid, brakes, tires and other systems to prove that it can safely land an astronaut crew after surviving the searing re-entry from Earth orbit.

The Dream Chaser is one of the three types of private sector ‘space taxis’ being developed with NASA seed money to restore America’s capability to blast humans to Earth orbit from American soil – a capability which was totally lost following the forced shutdown of NASA’s Space Shuttle program in 2011.

Dream Chaser commercial crew vehicle built by Sierra Nevada Corp docks at ISS

For the initial ground tests, the engineering test article was pulled by a tow truck at 10 and 20 MPH. Later this month tow speeds will be ramped up to 40 to 60 MPH.

Final assembly of the Dream Chaser test vehicle was completed at Dryden with installation of the wings and tail, following shipment from SNC’s Space Systems headquarters in Louisville, Colo.

Watch this exciting minute-long, time-lapse video showing attachment of the wings and tail:

In the next phase later this year, Sierra Nevada will conduct airborne captive carry tests using an Erickson Skycrane helicopter.

Atmospheric drop tests of the engineering test article in an autonomous free flight mode for Approach and Landing Tests (ALT) will follow to check the aerodynamic handling.

The engineering test article is a full sized vehicle.

Dream Chaser is a reusable mini shuttle that launches from the Florida Space Coast atop a United Launch Alliance Atlas V rocket and lands on the shuttle landing facility (SLF) runway at the Kennedy Space Center, like the Space Shuttle.

“It’s not outfitted for orbital flight. It is outfitted for atmospheric flight tests,” said Marc Sirangelo, Sierra Nevada Corp. vice president and SNC Space Systems chairman, to Universe Today.

“The best analogy is it’s very similar to what NASA did in the shuttle program with the Enterprise, creating a vehicle that would allow it to do significant flights whose design then would filter into the final vehicle for orbital flight,” Sirangelo told me.

NASA’s Dryden Flight Research Center welcomes SNC’s Dream Chaser shrink wrapped engineering test article for a flight test program in collaboration with NASA’s Commercial Crew Program this summer. Winds and tail were soon joined and ground testing has now begun. Credit: NASA/Tom Tschida Read more: http://www.universetoday.com/102020/sierra-nevada-dream-chaser-gets-wings-and-tail-starts-ground-testing/#ixzz2Yw1peNRJ — NASA’s Dryden Flight Research Center welcomes SNC’s Dream Chaser shrink wrapped engineering test article for a flight test program in collaboration with NASA’s Commercial Crew Program this summer. Winds and tail were soon joined and ground testing has now begun. Credit: NASA/Tom Tschida

Sierra Nevada Corp, along with Boeing and SpaceX are working with NASA in a public-private partnership using a combination of NASA seed money and company funds.

Each company was awarded contracts under NASA’s Commercial Crew Integrated Capability Initiative, or CCiCap, program, the third in a series of contracts aimed at kick starting the development of the private sector ‘space taxis’ to fly US and partner astronauts to and from low Earth orbit (LEO) and the International Space Station (ISS).

“We are the emotional successors to the shuttle,” says Sirangelo. “Our target was to repatriate that industry back to the United States, and that’s what we’re doing.”

The combined value of NASA’s Phase 1 CCiCap contracts is about $1.1 Billion and runs through March 2014.

Phase 2 contract awards will eventually lead to actual flight units after a down selection to one or more of the companies.

Everything depends on NASA’s approved budget, which seems headed for steep cuts in excess of a billion dollars if the Republican dominated US House has its way.

Dream Chaser awaits launch atop Atlas V rocket

The Commercial Crew program’s goal is to ensure the nation has safe, reliable and affordable crew transportation systems to space.

“Unique public-private partnerships like the one between NASA and Sierra Nevada Corporation are creating an industry capable of building the next generation of rockets and spacecraft that will carry U.S. astronauts to the scientific proving ground of low-Earth orbit,” said William Gerstenmaier, NASA’s associate administrator for human exploration and operations in Washington, in a statement.

“NASA centers around the country paved the way for 50 years of American human spaceflight, and they’re actively working with our partners to test innovative commercial space systems that will continue to ensure American leadership in exploration and discovery.”

All three commercial vehicles – the Boeing CST-100; SpaceX Dragon and Sierra Nevada Dream Chaser – are designed to carry a crew of up to 7 astronauts and remain docked at the ISS for more than 6 months.

The first orbital flight test of the Dream Chaser is not expected before 2016 and could be further delayed if NASA’s commercial crew budget is again slashed by the Congress – as was done the past few years.

In the meantime, US astronauts are totally dependent on Russia’s Soyuz capsule for rides to the ISS. NASA must pay Russia upwards of $70 million per seat until the space taxis are ready for liftoff – perhaps in 2017.

“We have got to get Commercial Crew funded, or we’re going to be paying the Russians forever,” said NASA Administrator Charles Bolden at Dryden. “Without Commercial Crew, we probably won’t have exploration.”

Concurrently, NASA is developing the Orion Crew capsule for missions to the Moon, Asteroids and beyond to Mars and other destinations in our Solar System -details here.

Ken Kremer

Scale models of NASA’s Commercial Crew program vehicles and launchers; Boeing CST-100, Sierra Nevada Dream Chaser, SpaceX Dragon. Credit: Ken Kremer/kenkremer.com — Scale models of NASA’s Commercial Crew program vehicles and launchers; Boeing CST-100, Sierra Nevada Dream Chaser, SpaceX Dragon.
Credit: Ken Kremer/kenkremer.com

Sierra Nevada Corp.'s Dream Chaser spacecraft landing on a traditional runway. Dream Chaser is being developed in collaboration with NASA's Commercial Crew Program during the Commercial Crew Integrated Capability initiative (CCiCAP). Credit: Sierra Nevada Corp. — Sierra Nevada Corp.’s Dream Chaser spacecraft landing on a traditional runway. Dream Chaser is being developed in collaboration with NASA’s Commercial Crew Program during the Commercial Crew Integrated Capability initiative (CCiCAP). Credit: Sierra Nevada Corp.

July 12, 2013December 23, 2015 by Nancy Atkinson

These Cubesats Could Use Plasma Thrusters to Leave Our Solar System

Artist concept of a 5 kg CubeSat with CubeSat Ambipolar Thruster (CAT) firing in low Earth orbit. Via Kickstarter.

Cubesats are all the rage these days: they’re usually inexpensive and quick to build and they can tag along on launches already scheduled for other things. We think of cubesats as being almost “disposable” satellites – tiny spacecraft that go into Earth orbit for a short time, do their science and then burn up harmlessly in Earth’s atmosphere. But a team of scientists have a more long-term, long-distance plan for their cubesats. Benjamin Longmier and James Cutler from the University of Michigan want to build cubesats that have tiny plasma thruster engines that could propel them into deep space, maybe even interstellar space.

They have a vision of their plasma-thruster cubesat waving as it speeds past the Voyager spacecraft at the edge of our Solar System.

They are working on what they call the CubeSat Ambipolar Thruster (CAT), a new plasma propulsion system. This thruster technology doesn’t exist all in one piece yet, but Longmeir and Cutler said they could put it together in months, with just a little funding. The CAT plasma thruster will propel a 5kg satellite into deep space, far beyond Earth orbit, at 1/1000th the cost of previous missions.

They’ve begun a $200,000 Kickstarter campaign to help fund their project. Their ideas of what these thruster propelled cubesats could do are mind-bogglingly exciting: flying through the plumes of Enceladus to look for life, studying and tagging asteroids, formation flying through Earth’s magnetosphere to learn more about solar flares and the aurora or just an interplanetary message in a bottle lasting for hundreds of millions of years in orbit around the Sun.

They think they can get a satellite up and flying within 18 months.

“The traditional funding process starts with some seed data, a large government grant and a large number of milestones and gates to go through,” said Longmier in a press release from the University of Michigan. “We’d like to leverage Kickstarter funds to compress that timeline and go from initial seed data to flight in about 18 months, a much faster time scale than is possible with traditional grants.”

The cubesats would be about as big as a loaf of bread and the thrusters – the first of its kind — would use superheated plasma directed through a magnetic field to propel the CubeSat. The duo says that with this technology, exploring interplanetary space and eventually other planets would become faster and cheaper than ever before.

While plasma rockets have been used before, they’ve only been used on big spacecraft like Deep Space 1 and DAWN. Longmier and Cutler are miniaturizing the system. Most of the thruster components have been built and have been tested individually, but they need help through Kickstarter to assemble everything into one compact thruster unit for testing the integrated components in the lab, then in Earth orbit, and then interplanetary space.

They’ve got more info on how the thrusters work on their Kickstarter page.

I dare you to tell me this isn’t exciting!

More info from the University of Michigan.

July 12, 2013December 23, 2015 by Nancy Atkinson

Hey Planet Earth! Get Ready to Smile and Wave for a Camera That’s a Billion Kilometers Away

This graphic shows the view of Earth and the portion of its surface that will be illuminated during the Earth imaging event by the Cassini spacecraft on July 19, 2013. Credit: NASA/JPL-Caltech.

July 19, 2013 will be a day that we should really all try to get along. Isn’t that a noble goal? And you can be a part of it in several different ways. In a special project, the Cassini spacecraft will be taking an image of Earth, from the spacecraft’s orbit around Saturn. Specifically, Cassini will be on the far side of Saturn when it snaps a picture of “us” between 21:27 to 21:42 UTC (5:27-5:42 pm EDT.) Cassini will be in just the right spot that it can “see” Earth, but Saturn will be blocking the glare from the Sun. There will likely be a dramatic view of Saturn and its rings in the foreground, with Earth off in the distance. Our home planet won’t be much more than a few pixels in the image, but it will be “us, …everyone you love, everyone you know, everyone you ever heard of, every human being who ever was,” as Carl Sagan said about the Pale Blue Dot image taken by the Voyager spacecraft.

“It will be a day to revel in the extraordinary achievements in the exploration of our solar system that have made such an interplanetary photo session possible,” said Cassini imaging team leader Carolyn Porco of the Space Science Institute, who had the idea for this special image. “And it will be a day for all of us to smile and celebrate life on the Pale Blue Dot.”

The event is called The Day The Earth Smiled, and this is very cool for several reasons.

Voyager 1 pale blue dot. Image credit: NASA/JPL

First, while Earth has been imaged before from other distant spacecraft (the famous Pale Blue Dot image and Cassini has taken pictures of Earth before) this is the first time that many of the inhabitants of Earth will know the image is being taken – hence the invitation to smile and wave.

Second, Saturn is now visible in the night sky — bright and shining — allowing us a direct line of sight to smile and wave back. No, we can’t see Cassini, but we know it’s there!

Plus, there’s other special chances to submit your own images – of Saturn, and of Earth, or of yourself in the moments Cassini is taking the image.

For all our astrophotographer friends out there, in cooperation with Astronomers Without Borders, TDTES is sponsoring a Saturn Mosaic project, where you can submit an image you’ve taken of Saturn. Urgency note: this has to be submitted by July 22, 2013.

Astronomers Without Borders is also sponsoring a special Saturn Observing Program, and they are encouraging people and organizations to either organize a special observing event for July 19 (you can register it as an official event here) or to attend an event near you. You can find TDTES events here. This can be a full-blown observing event with telescopes, or just an excuse to get together with friends to go out and look at Saturn in the night sky.

There are also two competitions — one is to submit photos that best represents Earth (the image must be taken on July 19, 2013) and another is to write an original song about this event. The digital versions of the winning entries will be beamed to space at a later date.

Find more information at The Day The Earth Smiled website, and the Astronomers Without Borders website.

NASA also has some charts on where and when to look for Saturn in the night sky here. NASA says these charts take into account the light travel time from Saturn.

And don’t forget to smile and think about all the good things about our world.

July 12, 2013December 23, 2015 by Nancy Atkinson

How Will Curiosity Drive to Mt. Sharp?

Curiosity Heading for Mount Sharp, Sol 329. Credit: NASA/JPL-Caltech

As the Martian crow flies, the Curiosity rover has about 8 kilometers (5 miles) to trek until it reaches its science destination of the foothills of Mount Sharp. But there will likely be twists and turns along the way. There could be boulders, pits and sand traps to avoid, as well as enticing science targets to stop and study. Just how will the rover be driven all that way? Are rover drivers “hand-driving” every turn or will Curiosity use its autonomous driving software? A combination of both, says Jeff Biesiadecki, MSL Rover Planner and flight software developer. In the Rover Update video below, he explains how each day’s drive will be planned and executed. The rover team is hoping to make at least 100 meters every day.

The image above shows the lower slopes of Mount Sharp at the end of a drive of about 135 feet (41 meters) during the 329th Martian day, or sol, of the rover’s work on Mars (July 9, 2013). That was the third drive by Curiosity since finishing observations at the mission’s final science target in the “Glenelg” area east of the rover’s landing site. Curiosity is driving to the southwest as it heads to Mt. Sharp.

How long will the drive to Mt. Sharp (Aeolis Mons) take? The MSL team expects it will take nine months to a year with stops for science.

“The mission is discovery driven,” said John Grotznger, who leads the MSL mission. “We will go to where the science takes us.”

July 12, 2013December 23, 2015 by Shannon Hall

Jets Boost — Not Hinder — Star Formation in Early Galaxies, New Study Suggests

An artist's conception of jets protruding from a quasar. Credit: ESO/M. Kornmesser

Understanding the formation of stars and galaxies early in the Universe’s history continues to be somewhat of an enigma, and a new study may have turned our current understanding on its head. A recent survey used archival data from four different telescopes to analyze hundreds of galaxies. The results provided overwhelming evidence that radio jets protruding from a galactic center enhance star formation – a result that directly contradicts current models, where star formation is hindered or even stopped.

All early galaxies consist of intensely luminous cores powered by huge black holes. These so-called active galactic nuclei, or AGN for short, are still the topic of intense study. One specific mechanism astronomers are studying is known as AGN feedback.

“Feedback is the astronomer’s slang term for the way in which an AGN – with its large amount of energy release – influences its host galaxy,” Dr. Zinn, lead researcher on this study, recently told Universe Today. He explained there is both positive feedback, in which the AGN will foster the main activity of the galaxy: star formation, and negative feedback, in which the AGN will hinder or even stop star formation.

Current simulations of galaxy growth invoke strong negative feedback.

“In most cosmological simulations, AGN feedback is used to truncate star formation in the host galaxy,” said Zinn. “This is necessary to prevent the simulated galaxies from becoming too bright/massive.”

Zinn et al. found strong evidence that this is not the case for a large number of early galaxies, claiming that the presence of an AGN actually enhances star formation. In such cases the total star formation rate of a galaxy may be boosted by a factor of 2 – 5.

Furthermore the team showed that positive feedback occurs in radio-luminous AGN. There is strong correlation between the far infrared (indicative of star formation) and the radio.

Now, a correlation between the radio and the far infrared is no stranger to galactic astronomy. Stars form in extremely dusty regions. This dust absorbs the starlight and re-emits it in the far infrared. The stars then die in huge supernova explosions, causing powerful shock-fronts, which accelerate electrons and lead to the emission of strong synchrotron radiation in the radio.

This correlation however is a stranger to AGN studies. The key lies in the radio jets, which penetrate far into the host galaxy itself. A “jet which is launched from the AGN hits the interstellar gas of the host galaxy and thereby induces supersonic shocks and turbulence,” explains Zinn. “This shortens the clumping time of gas so that it can condense into stars much more quick and efficiently.”

This new finding conveys that the exact mechanisms in which AGN interact with their host galaxies is much more complicated than previously thought. Future observations will likely shed a new understanding of the evolution of galaxies.

The team used data primarily from the Chandra Deep Field South image
but also data from Hubble, Herschel and Spitzer.

The results will be published in the Astrophysical Journal (preprint available here).

July 11, 2013March 16, 2017 by Fraser Cain

What’s the Most Earth-Like Planet In The Solar System?

Life on Earth got you down? Thinking you’d like to pick up and move to another planet? I’ve got bad news for you. Without protection, there’s no place in the entire Solar System that wouldn’t kill you in few seconds.

You’re looking at scorching temperatures, poisonous atmospheres, crushing gravity, bone chilling cold, a complete lack of oxygen, killer radiation, and more.

The entire Solar System is hostile to life as we know it.

If we had to choose from a range of terrible options, what would be the most Earthlike place in the Solar System?

We would want a world that has a similar gravity, similar atmospheric pressure and composition, protection from radiation, and a comfortable temperature. Just like the Earth.

Let’s look at a few candidates:

The Moon looks good. It’s close and… well, it’s close. It’s an airless world, so you’d need a spacesuit. Low gravity is bad news for your bones, which will lose mass and become brittle. Temperatures range from freezing cold to scorching hot, and there’s no atmosphere or significant magnetic field to protect you from the radiation of space.

While we’re suggesting moons, how about Titan, Saturn’s largest Moon?

It’s only 15% of Earth’s gravity, and the temperatures dip down to minus -179 degrees C; cold enough that it rains liquid methane. Even though the atmosphere is unbreathable, the good news is that the pressure is only a little higher than Earth’s. Which means you wouldn’t need a pressurized spacesuit, just a really, really warm coat.

Turning on the Tap - Commissioned artwork - Colonist tapping into a sub-surface aquifer (©Mars Foundation) — Turning on the Tap – Commissioned artwork – Colonist tapping into a sub-surface aquifer (©Mars Foundation)

How about Mars, the target of so many colonization plans and sci fi adventures?

The gravity of Mars is only 38% the gravity of Earth; and we don’t know what effect a long stay in this gravity would have on the human body. The atmosphere is poisonous carbon dioxide, and the pressure is less than 1% of sea level on Earth. So, you’d better pack a spacesuit. The temperatures can rise as high as a comfortable 35 degrees C, but then plunge down to -143 degrees C at the poles. One big problem with Mars is a total lack of magnetosphere. Radiation from space would be a constant hazard for anyone on the surface of the planet.

Perhaps another planet? How about Venus?

On the surface, it’s right out of the running. The temperature is an oven-like 462 degrees C, with a surface pressure 92 times more than Earth. The atmosphere is almost entirely carbon dioxide, with clouds of sulphuric acid. On the plus side, it has gravity roughly similar to Earth, and a thick atmosphere that would protect you from radiation.

Unfortunately, you’d die faster on the surface of Venus than almost anywhere else in the Solar System.

But… there is a place on Venus that’s downright lovely.

Up in the clouds.

Amazingly, if you rise up through the clouds of Venus to an altitude of 50-60 kilometers, the atmospheric pressure and temperature are the same as on Earth. The atmosphere would still be toxic carbon dioxide, but breathable air would be a “lifting gas” on Venus. You could float around the skies of Venus in a balloon made of breathable air. Stand out on the deck of your Venusian sky city in shorts and a T-shirt, soaking up the sunlight in regular Earth gravity.

Sounds idyllic, right?

So, opinions will vary. Some think Mars is the most Earthlike place in the Solar System, but in my opinion, the clouds of Venus are the place to go.

I’ll see you there.

July 11, 2013December 23, 2015 by Nancy Atkinson

Podcast: Accretion Discs

When too much material tries to come together, everything starts to spin and flatten out. You get an accretion disc. Astronomers find them around newly forming stars, supermassive black holes and many other places in the Universe. Today we’ll talk about what it takes to get an accretion disc, and how they help us understand the objects inside.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

“Accretion Discs” on the Astronomy Cast website, with shownotes and transcript.

And the podcast is also available as a video, as Fraser and Pamela now record Astronomy Cast as part of a Google+ Hangout (usually recorded every Monday at 3 pm Eastern Time):

July 11, 2013December 23, 2015 by Nancy Atkinson

Hubble Confirms Exoplanet Has a Blue Atmosphere

Artist’s impression of the deep blue planet HD 189733b, based on observations from the Hubble Space Telescope. Credit: NASA/ESA.

Since its discovery in 2005, exoplanet HD 189733b has been one of the most-observed planets orbiting another star, as its size, compact orbit, and proximity to Earth has made it a relatively easy target — as extrasolar planets go. From previous studies, astronomers thought the planet may have an enticing blue-sky atmosphere. Now, further examinations with the Hubble Space Telescope have confirmed this planet really does harbor an azure blue atmosphere, very similar to Earth’s ocean blue color.

But this is no ‘pale blue dot’ ocean world. It is a huge gas giant orbiting very close to its host star. It gets blasted with X-rays from its star — tens of thousands of times stronger than the Earth receives from the Sun — and endures wild temperature swings, reaching scorching temperatures of over 1,000 degrees Celsius. Astronomers say it likely rains glass – sideways — in howling 7,000 kilometer-per-hour winds.

Nope, not a place you’d want to visit.

But the new Hubble observations of its color are the first time an exoplanet’s color has been measured and confirmed. The astronomers measured how much light was reflected off the surface of HD 189733b — a property known as albedo.

“This planet has been studied well in the past, both by ourselves and other teams,” says Frédéric Pont of the University of Exeter, UK, co-author of a new paper. “But measuring its colour is a real first — we can actually imagine what this planet would look like if we were able to look at it directly.”

HD 189733b is a Jupiter-sized extrasolar planet orbiting a yellow dwarf star that is in a binary system called HD 189733 in the constellation of Vulpecula, near the Dumbell Nebula, approximately 62 light years from Earth.

The planet’s blue atmosphere does not come from the reflection of a warm ocean, but is due to a hazy, turbulent atmosphere thought to be laced with silicate particles, which scatter blue light. Earlier observations using different methods have reported evidence for scattering of blue light on the planet, but these most recent Hubble observations give robust confirming evidence, the researchers said.

To make their measurements, the team used Hubble’s Space Telescope Imaging Spectrograph (STIS) to look at the system before, during, and after the planet passed behind its host star as it orbited. As it slipped behind its star, the light reflected from the planet was temporarily blocked from view, and the amount of light observed from the system dropped – not by much, about one part in 10,000 — but this was enough for STIS to determine the albedo.

“We saw the brightness of the whole system drop in the blue part of the spectrum when the planet passed behind its star,” explains Tom Evans of the University of Oxford, UK, first author of the paper. “From this, we can gather that the planet is blue, because the signal remained constant at the other colours we measured.”

Albedo is a measure of how much incident radiation is reflected. The greater the albedo, the greater the amount of light reflected. This value ranges from 0 to 1, with 1 being perfect reflectivity and 0 being a completely black surface. The Earth has an albedo of around 0.4.

According to the team’s paper, HD 189733b has an albedo of 0.4 ± 0.12.

The team says this determination will help in future studies of the atmospheres of other extra solar planets, as well as continuing the studies of one of the most-examined planets orbiting another star.

“It’s difficult to know exactly what causes the colour of a planet’s atmosphere, even for planets in the Solar System,” says Pont [5]. “But these new observations add another piece to the puzzle over the nature and atmosphere of HD 189733b. We are slowly painting a more complete picture of this exotic planet.”

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July 11, 2013April 26, 2016 by David Dickinson

How to Spot and Track Satellites

A 10 second exposure of a bright pass of the International Space Station. (Photo by Author).

It’s a question we get all the time.

Watch the sky closely in the dawn or dusk hours, and you’ll likely see a moving “star” or two sliding by. These are satellites, or “artificial moons” placed in low Earth orbit. These shine via reflected sunlight as they pass hundreds of kilometres overhead.

Many folks are unaware that you can see satellites with the naked eye. I always make an effort to watch for these during public star parties and point them out. A bright pass of the International Space Station if often as memorable as anything that can be seen through the eyepiece. But after this revelation, “the question” soon follows- “What satellite is that?”

Welcome to the wonderful and highly addictive world of satellite tracking. Ground observers have been watching the skies since Sputnik 1 and the first satellite launch in October 1957. Armies of dedicated volunteers even participated in tracking the early launches of the Space Age with Operation Moonwatch.

Depiction of the apparent motion of a typical satellite overhead with respect to the observer. (Graphic created by author).

The Internet has offered a wealth of information for satellite hunters. Every time I write about “how to spot the ISS,” someone amazes me with yet another new tracker App that I hadn’t heard of. One of my favorites is still Heavens-Above. It’s strange to think that we’ve been visiting this outstanding website daily for a decade and a half now. Heavens-Above specializes in satellites, and will show you a quick listing of passes for brighter satellites once configured with your location. A nifty “quick check” for possibly resolving a mystery satellite is their link for “Daily Predictions for brighter satellites” Which will generate a list of visible passes by time.

Screenshot of a typical list of bright satellite passes from Heavens-Above. — Screenshot of a typical list of bright satellite passes from Heavens-Above filtered by brightness, time and location .

Looking at the time, direction, and brightness of a pass is crucial to satellite identification. No equipment is needed to start the hunt for satellites tonight, just a working set of eyes and information. We sometimes use a set of Canon image-stabilized 15x 45 binoculars to hunt for satellites too faint to see with the naked eye. We’ve seen the “Tool Bag” lost during an ISS EVA a few years back, as well as such “living relics” of the early Space Age as Canada’s first satellite Alloutte-1, and the Vanguards (Yes, they’re STILL up there!) using binocs.

A comparision of typical satellite orbits. (Credit — A comparison of typical satellite orbits. (Credit: Cmglee, Geo Swan graphic under a Creative Commons Attribution -Share Alike 3.0 unported license).

The trick to catching fainter satellites such as these is to “ambush” them. You’ll need to note the precise time that the selected satellite is going to pass near a bright star. Clicking on a selected satellite pass in Heavens-Above will give you a local sky chart with a time-marked path. I use a short wave portable AM radio tuned to WWV out of Fort Collins, Colorado for an accurate audible time signal. Just sit back, listen to the radio call out the time, and watch for the satellite to pass through the field of view near the target star.

Another great site for more advanced trackers is CALSky. Like Heavens-Above, CALSky will give you a customized list for satellite passes over your location. One cool extra feature on CALSky is the ability to set alerts for passes of the ISS near bright planets or transiting the Sun or Moon. These are difficult events to capture, but worth it!

The International Space Station transiting the Moon as captured by Mike Weasner from Cassiopeia Observatory in Arizona.

A great deal of what’s up there is space junk in the form of discarded hardware. Many satellites are on looping elliptical orbits, only visible to the naked eye when they are near perigee. Many satellites are located out at geosynchronous or geostationary orbits 35,786 kilometres distant and are invisible to the naked eye all together. These will often show up as streaks in astrophotos. An area notorious for geosynchronous satellites exists near the direction of M42 or Orion Nebula. During certain times of year, satellites can be seen nearby, nodding slowly north to south and back again. Around the March and September equinox seasons, geostationary satellites can be eclipsed by the shadow of the Earth. This can also cause communications difficulties, as many geo-sats also lie sunward as seen from the Earth around these times of year.

Probably one of the simplest satellite trackers for casual users is Space Weather’s Satellite Flybys page. North American users simply need to enter a postal code (worldwide users can track satellites via entering “country-state-city”) and a list of passes for your location is generated.

It’s a basic truism of satellite tracking that “aircraft blink; satellites don’t”. Know, we’re going to present an exception to this rule.

Some satellites will flash rhythmically due to a tumbling motion. This can be pretty dramatic to see. What you’re seeing is an expended booster, a cylinder tumbling due to atmospheric drag end-over-end. Some satellites can flash or flare briefly due to sunlight glinting off of reflective surfaces just right. Hubble, the ISS and the late NanoSail D2 can flare if conditions are just right.

The most dramatic of these are Iridium flares. The Iridium constellation consists of 66 active satellites used for satellite phone coverage in low-Earth orbit. When one of their three refrigerator-sized antennas catch the Sun just right, they can flare up to magnitude -8, or 40 times brighter than Venus. CALSky and Heavens-Above will also predict these events for your location.

Didn’t see a predicted satellite pass? Light pollution or bright twilight skies might be to blame. Keep in mind, passes lower to the horizon also fall prey to atmospheric extinction, as you’re looking through a thicker layer of the air than straight overhead. Some satellites such as the ISS or the USAF’s X-37B spy space plane even periodically boost or modify their orbits, throwing online prediction platforms off for a time.

More advanced satellite trackers will want to check out Celestrak and SAT-Flare Tracker 3D.

A screenshot example of TLE's for the ISS & Tiangong-1 from Celestrak. — A screenshot example of TLE’s for the ISS & Tiangong-1 from Celestrak.

I use a free tracking platform created by Sebastian Stoff known as Orbitron. Orbitron lets you set your observing location and tailor your view for what’s currently over head. You can run simulations and even filter for “visual only” passes, another plus. I also like Orbitron’s ability to run as a stand-alone system in the field, sans Internet connection. Just remember, for it to work properly, you’ll need to periodically update the .txt file containing the Two-Line Element (TLE) sets. TLE’s are data element sets that describe the orbital elements of a satellite. Cut and paste TLEs are available from Heavens-Above and Celestrak.

Orbitron screenshot for visible satellites using 'radar' mode... there's lots up there! (Credit: Orbitron). — Orbitron screenshot for visible satellites using ‘radar’ mode… there’s lots up there! (Credit: Orbitron).

For serious users, NORAD’s Space-Track is the best site for up-to-date TLEs. Space-Track requires a login and user agreement to access, but is available to satellite spotters and educators as a valuable resource. Space-Track also hosts a table of upcoming reentries, as does the Aerospace Corporation’s Center for Orbital & Reentry Debris Studies.

The SeeSat-L mailing list is also an excellent source of discussion among satellite trackers worldwide. Increasingly, this discussion is also moving over to Twitter, which is ideal for following swiftly evolving action in orbit. @Twisst, created by Jaap Meijers,will even Tweet you prior to an ISS pass!

And there’s always something new or strange in the sky for the observant. Satellites such as those used in the Naval Ocean Surveillance System (NOSS) were launched in groups, and are eerie to watch as they move in formations of 2 or 3 across the sky. These are difficult to catch, and all three of our sightings thus far of a NOSS pair have been surreptitious. And we’ve only had the camera ready to swing into action once to nab a NOSS pair;

A NOSS pair captured by the author. The multi-colored trail bisecting the path is an aircraft. Note a bit of "jitter" at the beginning of the exposure- I had to swing the camera into action quickly! — A NOSS pair captured by the author. The multi-colored trail to the left of the path is an aircraft. Note a bit of “jitter” at the beginning of the exposure- I had to swing the camera into action quickly!

Another bizarre satellite to catch in action is known as the Cloud-Aerosol LiDAR & Infrared Pathfinder Satellite for Observations, or CALIPSO. Part of the “afternoon A-Train” of sun-synchronous Earth observing satellites, you can catch the green LiDAR flashes of CALIPSO from the ground with careful planning, just as Gregg Hendry did in 2008-2009:

A CALIPSO LIDAR pass imaged by Gregg Hendry in 2008. My Hendry mentions that, "The hollow nature of the spots is likely due to some spherical aberration in the camera lens coupled with imperfect focus and is not representative of the laser beam's optical quality." — A CALIPSO LiDAR pass imaged by Gregg Hendry in 2008. My Hendry mentions that, “The hollow nature of the spots is likely due to some spherical aberration in the camera lens coupled with imperfect focus, and is not representative of the laser beam’s optical quality.” (Credit: Gregg Hendry, used with permission).

NASA even publishes a prediction table for CALIPSO lidar passes. I wonder how many UFO sightings CALIPSO has generated?

Artist's depiction of the A-Train constellation of Earth-Observing satellites. (Credit: NASA). — Artist’s depiction of the A-Train constellation of Earth-Observing satellites. (Credit: NASA).

And speaking of photography, it’s easy to catch a bright pass such as the ISS on camera. Shooting a satellite pass with a wide field is similar to shooting star trails; just leave the shutter open for 10-60 seconds with a tripod mounted camera. Modern DSLRs allow you to do several test exposures prior to the pass, to get the ISO, f/stop, and shutter speed calibrated to local sky conditions.

You can even image the ISS through a telescope. Several sophisticated rigs exist to accurately track and image the space station through a scope, or you could use our decidedly low-tech but effective hand-guided method;

And that’s a brief overview of the exciting world of sat-spotting… let us know of your tales of triumph and tragedy as you sleuth out what’s going on overhead!

July 10, 2013December 23, 2015 by Nancy Atkinson

New Horizons: I Spy Pluto and Charon!

New Horizons LOng Range Reconnaissance Imager (LORRI) composite image showing the detection of Pluto’s largest moon, Charon, cleanly separated from Pluto itself. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The New Horizons spacecraft is still about 880 million kilometers (550 million miles) from Pluto, but on July 1 and 3, 2013, the spacecraft’s LOng Range Reconnaissance Imager (LORRI) was able to detect not only Pluto, but its largest moon, Charon, visible and cleanly separated from Pluto itself. Charon orbits about 19,000 kilometers (12,000 miles) away from Pluto, and seen from New Horizons, that’s only about 0.01 degrees away.

“The image itself might not look very impressive to the untrained eye, but compared to the discovery images of Charon from Earth, these ‘discovery’ images from New Horizons look great!” said New Horizons Project Scientist Hal Weaver. “We’re very excited to see Pluto and Charon as separate objects for the first time from New Horizons.”

The frame on the left in the grouping of images above is an average of six different LORRI images, each taken with an exposure time of 0.1 second. The frame to the right is the same composite image but with Pluto and Charon circled; Pluto is the brighter object near the center and Charon is the fainter object near its 11 o’clock position. The circles also denote the predicted locations of the objects, showing that Charon is where the team expects it to be, relative to Pluto. No other Pluto system objects are seen in these images.

These images are just a hint of what’s to come when New Horizons gets closer to the Pluto system. On July 14, 2015, the spacecraft is scheduled to pass just 12,500 kilometers (7,750 miles) above Pluto’s surface, where LORRI will be able to spot features about the size of a football field.

“We’re excited to have our first pixel on Charon,” said New Horizons Principal Investigator Alan Stern, “but two years from now, near closest approach, we’ll have almost a million pixels on Charon –and I expect we’ll be about a million times happier too!”

Pluto has five known moons (and naming them has been a bit controversial). Will New Horizons find even more?

Source: New Horizons