Do Stars Move? Tracking Their Movements Across the Sky

How Fast Are Stars Moving?


The night sky, is the night sky, is the night sky. The constellations you learned as a child are the same constellations that you see today. Ancient people recognized these same constellations. Oh sure, they might not have had the same name for it, but essentially, we see what they saw.

But when you see animations of galaxies, especially as they come together and collide, you see the stars buzzing around like angry bees. We know that the stars can have motions, and yet, we don’t see them moving?

How fast are they moving, and will we ever be able to tell?

Stars, of course, do move. It’s just that the distances are so great that it’s very difficult to tell. But astronomers have been studying their position for thousands of years. Tracking the position and movements of the stars is known as astrometry.

We trace the history of astrometry back to 190 BC, when the ancient Greek astronomer Hipparchus first created a catalog of the 850 brightest stars in the sky and their position. His student Ptolemy followed up with his own observations of the night sky, creating his important document: the Almagest.

Printed rendition of a geocentric cosmological model from Cosmographia, Antwerp, 1539. Credit: Wikipedia Commons/Fastfission

In the Almagest, Ptolemy laid out his theory for an Earth-centric Universe, with the Moon, Sun, planets and stars in concentric crystal spheres that rotated around the planet. He was wrong about the Universe, of course, but his charts and tables were incredibly accurate, measuring the brightness and location of more than 1,000 stars.

A thousand years later, the Arabic astronomer Abd al-Rahman al-Sufi completed an even more detailed measurement of the sky using an astrolabe.

One of the most famous astronomers in history was the Danish Tycho Brahe. He was renowned for his ability to measure the position of stars, and built incredibly precise instruments for the time to do the job. He measured the positions of stars to within 15 to 35 arcseconds of accuracy. Just for comparison, a human hair, held 10 meters away is an arcsecond wide.

Also, I’m required to inform you that Brahe had a fake nose. He lost his in a duel, but had a brass replacement made.

In 1807, Friedrich Bessel was the first astronomer to measure the distance to a nearby star 61 Cygni. He used the technique of parallax, by measuring the angle to the star when the Earth was on one side of the Sun, and then measuring it again 6 months later when the Earth was on the other side.

With parallax technique, astronomers observe object at opposite ends of Earth’s orbit around the Sun to precisely measure its distance. Credit: Alexandra Angelich, NRAO/AUI/NSF.

Over the course of this period, this relatively closer star moves slightly back and forth against the more distant background of the galaxy.

And over the next two centuries, other astronomers further refined this technique, getting better and better at figuring out the distance and motions of stars.

But to really track the positions and motions of stars, we needed to go to space. In 1989, the European Space Agency launched their Hipparcos mission, named after the Greek astronomer we talked about earlier. Its job was to measure the position and motion of the nearby stars in the Milky Way. Over the course of its mission, Hipparcos accurately measured 118,000 stars, and provided rough calculations for another 2 million stars.

That was useful, and astronomers have relied on it ever since, but something better has arrived, and its name is Gaia.

Credit: ESA/ATG medialab; Background Credit: ESO/S. Brunier

Launched in December 2013, the European Space Agency’s Gaia in is in the process of mapping out a billion stars in the Milky Way. That’s billion, with a B, and accounts for about 1% of the stars in the galaxy. The spacecraft will track the motion of 150 million stars, telling us where everything is going over time. It will be a mind bending accomplishment. Hipparchus would be proud.

With the most precise measurements, taken year after year, the motions of the stars can indeed be calculated. Although they’re not enough to see with the unaided eye, over thousands and tens of thousands of years, the positions of the stars change dramatically in the sky.

The familiar stars in the Big Dipper, for example, look how they do today. But if you go forward or backward in time, the positions of the stars look very different, and eventually completely unrecognizable.

When a star is moving sideways across the sky, astronomers call this “proper motion”. The speed a star moves is typically about 0.1 arc second per year. This is almost imperceptible, but over the course of 2000 years, for example, a typical star would have moved across the sky by about half a degree, or the width of the Moon in the sky.

A 20 year animation showing the proper motion of Barnard’s Star. Credit: Steve Quirk, images in the Public Domain.

The star with the fastest proper motion that we know of is Barnard’s star, zipping through the sky at 10.25 arcseconds a year. In that same 2000 year period, it would have moved 5.5 degrees, or about 11 times the width of your hand. Very fast.

When a star is moving toward or away from us, astronomers call that radial velocity. They measure this by calculating the doppler shift. The light from stars moving towards us is shifted towards the blue side of the spectrum, while stars moving away from us are red-shifted.

Between the proper motion and redshift, you can get a precise calculation for the exact path a star is moving in the sky.

Credit: ESA/ATG medialab

We know, for example, that the dwarf star Hipparcos 85605 is moving rapidly towards us. It’s 16 light-years away right now, but in the next few hundred thousand years, it’s going to get as close as .13 light-years away, or about 8,200 times the distance from the Earth to the Sun. This won’t cause us any direct effect, but the gravitational interaction from the star could kick a bunch of comets out of the Oort cloud and send them down towards the inner Solar System.

The motions of the stars is fairly gentle, jostling through gravitational interactions as they orbit around the center of the Milky Way. But there are other, more catastrophic events that can make stars move much more quickly through space.

When a binary pair of stars gets too close to the supermassive black hole at the center of the Milky Way, one can be consumed by the black hole. The other now has the velocity, without the added mass of its companion. This gives it a high-velocity kick. About once every 100,000 years, a star is kicked right out of the Milky Way from the galactic center.

A rogue star being kicked out of a galaxy. Credit: NASA, ESA, and G. Bacon (STScI)

Another situation can happen where a smaller star is orbiting around a supermassive companion. Over time, the massive star bloats up as supergiant and then detonates as a supernova. Like a stone released from a sling, the smaller star is no longer held in place by gravity, and it hurtles out into space at incredible speeds.

Astronomers have detected these hypervelocity stars moving at 1.1 million kilometers per hour relative to the center of the Milky Way.

All of the methods of stellar motion that I talked about so far are natural. But can you imagine a future civilization that becomes so powerful it could move the stars themselves?

In 1987, the Russian astrophysicist Leonid Shkadov presented a technique that could move a star over vast lengths of time. By building a huge mirror and positioning it on one side of a star, the star itself could act like a thruster.

An example of a stellar engine using a mirror and a Dyson Swarm. Credit: Vedexent at English Wikipedia (CC BY-SA 3.0)

Photons from the star would reflect off the mirror, imparting momentum like a solar sail. The mirror itself would be massive enough that its gravity would attract the star, but the light pressure from the star would keep it from falling in. This would create a slow but steady pressure on the other side of the star, accelerating it in whatever direction the civilization wanted.

Over the course of a few billion years, a star could be relocated pretty much anywhere a civilization wanted within its host galaxy.

This would be a true Type III Civilization. A vast empire with such power and capability that they can rearrange the stars in their entire galaxy into a configuration that they find more useful. Maybe they arrange all the stars into a vast sphere, or some kind of geometric object, to minimize transit and communication times. Or maybe it makes more sense to push them all into a clean flat disk.

Amazingly, astronomers have actually gone looking for galaxies like this. In theory, a galaxy under control by a Type III Civilization should be obvious by the wavelength of light they give off. But so far, none have turned up. It’s all normal, natural galaxies as far as we can see in all directions.

For our short lifetimes, it appears as if the sky is frozen. The stars remain in their exact positions forever, but if you could speed up time, you’d see that everything is in motion, all the time, with stars moving back and forth, like airplanes across the sky. You just need to be patient to see it.

Can We Really Get to Alpha Centauri?

In a previous episode, I said that traveling within the Solar System is hard enough, traveling to another star system in our lifetime is downright impossible. Many of you said it was the most depressing episode I’ve ever done .

The distance to Pluto is, on average, about 40 astronomical units. That’s 40 times the distance from the Sun to the Earth. And New Horizons, the fastest spacecraft traveling in the Solar System took about 10 years to make the journey.

The distance to Alpha Centauri is about 277,000 astronomical units away (or 4.4 light-years). That’s about 7,000 times further than Pluto. New Horizons could make the journey, if you were willing to wait about 70,000 years. That’s about twice as long as you’d be willing to wait for Half Life 3.

But my video clearly made an impact on a plucky team of rocket scientists, entrepreneurs and physicists, who have no room in their personal dictionary for the word “impossible”. Challenge accepted, they said to themselves.

In early April, 2016, just 8 months after I said it was probably never going to happen, the billionaire Yuri Milner and famed physicist Stephen Hawking announced a strategy to send a spacecraft to another star within our lifetime. In your face Fraser, they said… in your face.

Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity's first interstellar voyage. Credit: breakthroughinitiatives.org
Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity’s first interstellar voyage. Credit: breakthroughinitiatives.org

The project will be called Breakthrough Starshot, and it’s led by Pete Worden, the former director of NASA’s AMES Research Center – the people working on a warp drive.

The team announced that they’re spending $100 million to investigate the technology it’ll take to send a spacecraft to Alpha Centauri, making the trip in just 20 years. And by doing so, they might just revolutionize the way spacecraft travel around our own Solar System.

So, what’s the plan? According to their announcement, the team is planning to create teeny tiny lightsail spacecraft, and accelerate them to 20% the speed of light using lasers. Yes, everything’s made better with lasers .

We’ve talked about solar sails in the past, but the gist is that photons of light can impart momentum when they bounce off something. It’s not very much, but if you add a tremendous amount of photons, the impact can be significant. And because those photons are going the speed of light, the maximum speed for the spacecraft, in theory, is just shy of the speed of light (thanks relativity).

You can get those photons from the Sun, but you can also get them from a directed laser beam, designed to fill the sails with photons, without actually melting the spacecraft.

In the past, engineers have talked about solar sails that might be thousands of kilometers across, made of gossamer sheets of reflective fabric. Got that massive, complicated sail in your mind?

Now think smaller. The Starshot spacecraft will measure just a few meters across, with a thickness of just a few atoms. The sail would then pull a microscopic payload of instruments. A tiny chip, capable of gathering data and transmitting information – these are called Starchips. Not even enough room for water bear crew quarters.

A phased laser array, perhaps in the high desert of Chile, propels sails on their journey. Credit: Breakthrough Initiatives.
A phased laser array, perhaps in the high desert of Chile, propels sails on their journey. Credit: Breakthrough Initiatives.

With such a low mass, a powerful laser should be able to accelerate them to 20% the speed of light, almost instantly, making a trip to Alpha Centauri only take about 20 years.

Since each Starshot might only cost a few dollars to make, the company could manufacture thousands and thousands, place them into orbit, and then start bugzapping them off to different stars.

There are, of course, some massive engineering hurdles to overcome.

The first is the density of the interstellar medium. Although it’s almost completely empty in between the stars, there are the occasional dust particles. Normally harmless, the Starshots would be smashing into them at 20% the speed of light, which would be catastrophic.

The second problem is that this is a one-way trip. Once it’s going 20% the speed of light, there’s no way to slow the spacecraft down again (unless the Alpha Centaurans have a braking system in place). Just imagine the motion blur and targeting problems when you’re trying to take photos at relativistic speeds.

The third problem, and this is a big one, is that the miniaturization of the spacecraft means that you can’t have a big transmitter. Communicating across the light years takes a LOT of power. Maybe they’ll connect up into some kind of array and share the power requirement, or use lasers to communicate back. Maybe they’ll relay the data back like a Voltron daisy chain.

Even though the idea of traveling to another star might seem overly ambitious today, this technology actually makes a lot of sense for exploration in our own Solar System. We could bugzap little spacecraft to Venus, Mars, the outer planets and their moons – even deep into the Kuiper Belt and the totally unexplored Oort cloud. We could have this whole Solar System on exploration lockdown in just a few decades.

Even if a mission to Alpha Centauri is currently science fiction, this miniaturization is going to be the way we learn more about the Solar System we live in. Let’s get going!

Will We Ever Reach Another Star?

We hear about discoveries of exoplanets every day. So how long will it take us to find another planet like Earth?

There are two separate parts of your brain I would like to speak with today. First, I want to talk to the part that makes decisions on who to vote for, how much insurance you should put on your car and deals with how not paying taxes sends you to jail. We’ll call this part of your brain “Kevin”.

The rest of your brain can kick back, especially the parts that knows what kind of gas station you prefer, whether Lena Dunham is awesome or “the most awesome”, whether a certain sports team is the winningest, or believes that you can leave a casino with more money than you went in with. We will call this part “Other Kevin”, in honor of Dave Willis.

Okay Kevin, you’re up. I’m going to cut to the gut punch, Kevin. Between you and me, it is my displeasure to inform you that science fiction has ruined “Other Kevin”. Just like comic books have compromised their ability to judge the likelihood of someone acquiring heat vision, science fiction has messed up their sense of scale about interstellar travel.

But you already knew that. Not like “Other Kevin”, you’re the smart one. In the immortal words of Douglas Adams, “space is big”. But when he said that, Douglas was really understating how mind-bogglingly big space really is.

The nearest star is 4 light years away. That means that light, traveling at 300,000 kilometers per second would still need 4 YEARS to reach the nearest star. The fastest spacecraft ever launched by humans would need tens of thousands of years to make that trip.

But science fiction encourages us to think it’s possible. Kirk and Spock zip from world to world with a warp drive violating the Prime Directive right in it’s smug little Roddenberrian face. Han and Chewy can make the Kessel run in only 12 parsecs, which is confusing and requires fan theories to resolve the cognitive space-distance dissonance, and Galactica, The SDF 3, and Guild Navigators all participate in the folding of space.

And science fiction knows everything that’s about to happen, right? Like cellphones. Additionally Kevin, I know what you’re thinking and I’m not going to tear into Lucas on this. It’s too easy, and my ilk do it a little too often. Plus, I’m saving it up for Abrams. Sorry Kevin. Got a little distracted there.

The point is, science fiction is doing colossal hand waving. They’re glossing over key obstacles, like the laws of physics.

Stay with me here.This isn’t like jaywalking bylaws that “probably don’t apply to you at that very moment”, these are the physical laws of the universe that will deliver a complete junk-kicking if you try and pretend they’re not interested in crushing your little atmosphere requiring, century lifespan, conventional propulsion drive dreams.

So let’s say that we wanted to actually send a spacecraft to another star, whilst obeying the laws of physics. We’ll set the bar super low. We’re not talking about massive cruise ships filled with tourists seeking the delights of the super funzone planetoid, Itchy and Scrachylandia Prime.

David Hardy's illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars.  (Credit: D. Hardy)
David Hardy’s illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars. (Credit: D. Hardy)

I’m not talking about sending a crack team of power armored space marines to defend colonists from xenomorphs, or perhaps take other more thorough measures.

No, I’m talking about getting an operational teeny robotic spacecraft from Earth to Alpha Centauri. The fastest spacecraft we’ve ever launched is New Horizons. It’s currently traveling at 14 kilometres per second. It would take this peppy little probevette 100,000 years to get to the nearest star.

This is mostly due to our lack of reality shattering propulsion. Our best propellant option is an ion engine, used by NASA’s Dawn spacecraft. According to much adored Ian “Handsome” O’Neill from Discovery Space, we’d be looking at 19,000 years to get to Alpha Centauri if we used an ion engine and added a gravitational assist from the Sun.

Just think of what we could do with those 81,000 years we’d be saving! I’m going to learn the dulcimer!
We can start shearing back the reality curtain and throw money and resources to chase nearby speculative propulsion tech. Things like antimatter engines, or even dropping nuclear bombs out the back of a spacecraft

The best idea in the hopper is to use solar sails, like the Planetary Society’s Lightsail.
Use the light from the Sun as well as powerful lasers to accelerate the craft.

Ion Propulsion
Ion Propulsion System Test for Deep Space 1. Image Credit: NASA/JPL

But if we’re going to start down that road, we could also send microscopic lightsail spacecraft which are much easier to accelerate. Once these miniprobes reached their target, they could link up and form a communications relay, or even robotic factories.

Sorry, I think that was my “Other Kevin” talking. So where are we at, fo’ reals?

Harold “Sonny” White, a researcher with NASA announced that they’ve been testing out a futuristic technology called an EM drive. They detected a very slight “thrust” in their equipment that might mean it could be possible to maybe push a spacecraft in space without having to expel propellent like a chemical rocket or an ion drive.

What’s that, Kevin? Yes, you should totally be skeptical. You’re right, that last bit was a salad of weasel words.

Even if this crazy drive actually works, it still needs to obey the laws of physics. You couldn’t go faster than the speed of light and you would need a remarkable source of energy to power the reactor. Also, yes, Kevin, you’re right NASA is working on a warp drive. There’s no need to yell.

NASA is also working on an actual warp drive concept known as an alcubierre drive. It would actually do what science fiction has claimed: to warp space to allow faster than light travel. But by working on it, I mean, they’ve done a lot of fancy math.

But once they get all the math done, they can just go build it right? This concept is so theoretical that physicists are still arguing whether powering an alcubierre drive would take more energy than contained within the entire Universe. Which, I think we can call an obstacle.

Oh, one more thing. “Other Kevin”, thanks for being so patient. Here’s your reward. Unicorns are real, and Kevin has been lying to you this whole time. Go get ‘em tiger. Place your bets. When do you think we’ll send our first probe towards another star? Predict the departure date in the comments below.

X-37B Air Force Space Plane Launches on 4th Mystery Military Mission and Solar Sailing Test

Blastoff of the X-37B spaceplane on United Launch Alliance (ULA) Atlas V rocket with the OTV-4 AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: Ken Kremer/kenkremer.com
Story updated with additional details and photos[/caption]

The X-37B, a reusable Air Force space plane launched today, May 20, from Cape Canaveral, Florida, on its fourth mission steeped in mystery as to its true goals for the U.S . military and was accompanied by ten tiny cubesat experiments for NASA and the NRO, including a solar sailing demonstration test for The Planetary Society.

The military space plan successfully blasted off for low Earth orbit atop a 20 story United Launch Alliance (ULA) Atlas V rocket on the clandestine Air Force Space Command 5 (AFSPC-5) satellite mission for the U.S. Air Force Rapid Capabilities Office at 11:05 a.m. EDT (1505 GMT) today, May 20, from Space Launch Complex-41 on Cape Canaveral Air Force Station, Florida.

The weather cooperated for a spectacular liftoff from the Florida space coast, which was webcast live by ULA until five minutes after launch when it went into a communications blackout shortly after announcing the successful ignition of the Centaur upper stage.

The exact launch time was classified until it was released by the Department of Defense this morning. Early this morning the four hour launch window was narrowed down to two small windows of opportunity.

USAF X-37B orbital test vehicle launches atop  United Launch Alliance Atlas V rocket on May 20, 2015 on OTV-4 mission. Credit: Alex Polimeni
USAF X-37B orbital test vehicle launches atop United Launch Alliance Atlas V rocket on May 20, 2015 on OTV-4 mission. Credit: Alex Polimeni

Among the experiments for the flight are 10 CubeSats housed in the Aft Bulkhead Carrier (ABC) located below the Centaur upper stage. Together they are part of the National Reconnaissance Office’s (NRO’s) Ultra Lightweight Technology and Research Auxiliary Satellite (ULTRASat). The 10 CubeSats in ULTRASat are managed by the NRO and NASA. They are contained in eight P-Pods from which they will be deployed in the coming days.

Also aboard the X-37B is a NASA materials science experiment called METIS and an advanced Hall thruster experiment. The Hall thruster is a type of electric propulsion device that produces thrust by ionizing and accelerating a noble gas, usually xenon.

Following primary spacecraft separation the Centaur will change altitude and inclination in order to release the CubeSat spacecraft.

They are sponsored by the National Reconnaissance Office (NRO) and NASA and were developed by the U.S. Naval Academy, the Aerospace Corporation, the Air Force Research Laboratory, California Polytechnic State University, and The Planetary Society.

LightSail marks the first controlled, Earth orbit solar sail flight according to the non-profit Planetary Society. Photons from the sun should push on the solar sails.

“The purpose of this LightSail demonstration test is to verify telemetry, return photos return and to test the deployment of the solar sails,” said Bill Nye, the Science Guy), and President of The Planetary Society, during the X-37B launch webcast.

“LightSail is comprised of three CubeSats that measure about 30 cm by 10 cm.”

“It’s smaller than a shoebox, everybody! And the sail that will come out of it is super shiny mylar. We’re very hopeful that the thing will deploy properly, the sunlight will hit it and we’ll get a push.”

United Launch Alliance Atlas V launch of USAF X-37B orbital test vehicle on May 20, 2015. Credit: Julian Leek
United Launch Alliance Atlas V launch of USAF X-37B orbital test vehicle on May 20, 2015. Credit: Julian Leek

The Boeing-built X-37B is an unmanned reusable mini shuttle, also known as the Orbital Test Vehicle (OTV) and is flying on the OTV-4 mission. It launches vertically like a satellite but lands horizontally like an airplane and functions as a reliable and reusable space test platform for the U.S. Air Force.

“ULA is honored to launch this unique spacecraft for the U.S Air Force. Congratulations to the Air Force and all of our mission partners on today’s successful launch! The seamless integration between the Air Force, Boeing, and the entire mission team culminated in today’s successful launch of the AFSPC-5 mission” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.

The two stage Atlas V stands 206 feet tall and weighs 757,000 pounds.

The X-37B was carried to orbit by the Atlas V in its 501 configuration which includes a 5.4-meter-diameter payload fairing and no solid rocket motors. The Atlas first stage booster for this mission was powered by the RD AMROSS RD-180 engine generating some 850,000 pounds of thrust and fired for approximately the first four and a half minutes of flight. The Centaur upper stage was powered by the Aerojet Rocketdyne RL10C-1 engine.

The X-37B space plane was to separate from the Centaur about 19 minutes after liftoff. The Centaur continued firing separately with the CubeSat deployment, including the Planetary Society’s LightSail test demoonstration, into a different orbit later.

Overall this was ULA’s sixth launch of the 501 configuration the 54th mission to launch on an Atlas V rocket. This was also ULA’s fifth launch in 2015 and the 96th successful launch since the company was formed in December 2006.

The OTV is somewhat like a miniature version of NASA’s space shuttles.

Boeing has built two OTV vehicles. But it is not known which of the two vehicles was launched today.

Altogether the two X-37B vehicles have spent a cumulative total of 1367 days in space during the first three OTV missions and successfully checked out the vehicles reusable flight, reentry and landing technologies.

The 11,000 pound (4990 kg) state-of -the art reusable OTV space plane was built by Boeing and is about a quarter the size of a NASA space shuttle. It was originally developed by NASA but was transferred to the Defense Advanced Research Projects Agency (DARPA) in 2004.

USAF X-37B orbital test vehicle poised for launch atop  United Launch Alliance Atlas V rocket on May 20, 2015 on OTV-4 mission. Credit: Alex Polimeni
USAF X-37B orbital test vehicle poised for launch atop United Launch Alliance Atlas V rocket on May 20, 2015 on OTV-4 mission. Credit: Alex Polimeni

All three OTV missions to date have launched from Cape Canaveral, Florida and landed at Vandenberg Air Force Base, California. Future missions could potentially land at the shuttle landing facility at the Kennedy Space Center, Florida.

The first OTV mission launched on April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit.

The following flights were progressively longer in duration. The second OTV mission began March 5, 2011, and concluded on June 16, 2012, after 468 days on orbit. The third OTV mission launched on Dec. 11, 2012 and landed on Oct. 17, 2014 after 674 days in orbit.

The vehicle measures 29 ft 3 in (8.9 m) in length with a wingspan of 14 ft 11 in (4.5 m). The payload bay measures 7 ft × 4 ft (2.1 m × 1.2 m). The space plane is powered by Gallium Arsenide Solar Cells with Lithium-Ion batteries.

Among the primary mission goals of the first three flights were check outs of the vehicles capabilities and reentry systems and testing the ability to send experiments to space and return them safely. OTV-4 will shift somewhat more to conducting research.

“We are excited about our fourth X-37B mission,” Randy Walden, director of the USAF’s Rapid Capabilities Office, said in a statement. “With the demonstrated success of the first three missions, we’re able to shift our focus from initial checkouts of the vehicle to testing of experimental payloads.”

US Air Force X-37B OTV-4 mini space shuttle is encapsulated in 5 meter payload fairing and bolted atop an Atlas 5 rocket at Pad 41 at Cape Canaveral Air Force Station, Florida prior to planned 20 May 2015 launch.  Credit: Ken Kremer/kenkremer.com
US Air Force X-37B OTV-4 mini space shuttle is encapsulated in 5 meter payload fairing and bolted atop an Atlas 5 rocket at Pad 41 at Cape Canaveral Air Force Station, Florida prior to planned 20 May 2015 launch. Credit: Ken Kremer/kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

Launch of the X-37B spaceplane on a United Launch Alliance (ULA) Atlas V rocket with the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: ULA
Launch of the X-37B spaceplane on a United Launch Alliance (ULA) Atlas V rocket with the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT, May 20, 2015 from Space Launch Complex-41. Credit: ULA
A United Launch Alliance (ULA) Atlas V rocket successfully launched the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT today, Wednesday, May 20, 2015 from Space Launch Complex-41. Credit: ULA
A United Launch Alliance (ULA) Atlas V rocket successfully launched the AFSPC-5 satellite for the U.S. Air Force at 11:05 a.m. EDT today, Wednesday, May 20, 2015 from Space Launch Complex-41. Credit: ULA

Hunting LightSail in Orbit

The hunt is on in the satellite tracking community, as the U.S. Air Force’s super-secret X-37B space plane rocketed into orbit today atop an Atlas V rocket out of Cape Canaveral.  This marks the start of OTV-4, the X-37B’s fourth trip into low Earth orbit. And though NORAD won’t be publishing the orbital elements for the mission, it is sure to provide an interesting hunt for backyard satellite sleuths on the ground.

Previous OTV missions were placed in a 40 to 43.5 degree inclination orbit, and the current NOTAMs cite a 61 degree azimuth angle for today’s launch out of the Cape which suggests a slightly shallower 39 degree orbit. Such variability speaks to the versatile nature of the second stage Centaur motor.

Image credit:
A capture of the X-37B in orbit. Image credit and copyright: Luke (Catching up)

There’s also been word afoot that future X-37B missions may return to Earth at the Kennedy Space Center, just like the Space Shuttle. To date, the X-37B has only landed at Vandenberg Air Force Base in California.

But there’s also another high interest payload being released along with a flock of CubeSats aboard AFPSC-5: The Planetary Society’s Lightsail-1.

Image credit:
The UltraSat P-POD CubeSat dispenser. Image credit: United Launch Alliance

About the size of a loaf of bread and the result of a successful Kickstarter campaign, LightSail is set to demonstrate key technologies in low Earth orbit before the Planetary Society’s main solar sail demonstrator takes to space in 2016.

The idea of using solar wind pressure for space travel is an enticing one. A big plus is the fact that unlike chemical propulsion, a solar sail does not need to contend with hauling the mass of its own fuel. The idea of using a solar sail plus a focused laser to propel an interstellar spacecraft has long been a staple of science fiction. But light-sailing technology has had a troubled history—the Planetary Society lost its Cosmos-1 mission launched from a Russian submarine in 2001. JAXA has fared better with its Venus-bound IKAROS, also equipped with a solar sail. To date, the IKAROS solar sail is the largest that has been deployed, at 20-metres on the diagonal.

Another use for space sail technology is the commanded reentry of spacecraft at the end of their mission life, as demonstrated by NanoSail-D2 in 2011.

Prospects of seeing LightSail may well be similar to what we had hunting for NanoSail-D2. Unfolded, LightSail will be 32 square meters in size, or about 5.6 meters on a side. NanoSail-D2 measured 3.1 meters on a side, and the reflective panels on the Iridium satellites which produce brilliant Iridium flares exceeding Venus in brightness measure about the size of a large rectangular door at 1 x 3 meters. Even the Hubble Space Telescope can flare on occasion as seen from the ground if one of its massive solar arrays catches the Sun just right.

Image credit:
Hubble can flare too! Image credit: David Dickinson

The 39 degree orbital inclination angle will also limit visible passes to from about 45 degrees north to 45 degrees south latitude.

Hunting down X-37B and LightSail will push ground observing skills to the max. Like NanoSail-D2, LightSail probably won’t be visible to the naked eye until it flares. What we like to do is note when a faint satellite is set to pass by a bright star, then sit back with our trusty 15x 45 image-stabilized binoculars and watch. We caught sight of the ‘tool bag’ lost during an ISS EVA in 2009 in this fashion. There it was, drifting past Spica as a +7th magnitude ‘star’. The key to this method is an accurate prediction—Heavens-Above now overlays orbital satellite passes on all-sky charts—and an accurate time source. We prefer to have WWV radio running in the background, as it’ll call out the time signal so we don’t have to take our eyes off the sky.

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The orbital trace of OTV-3. Image credit: Orbitron

Veteran satellite watcher Ted Molczan recently discussed the prospects for spotting LightSail once it’s deployed.  “By then, the orbit will be visible from the northern hemisphere during the middle of the night. The southern hemisphere may have marginal evening passes. Note that the high area to mass ratio with the sail deployed, combined with the low perigee height, is expected to result in decay as soon as a couple days after deployment.”

Read a further discussion concerning OTV-4 and associated payloads by Mr. Molczan on the See-Sat message board here.

The Planetary Society’s Jason Davis confirmed for Universe Today that LightSail will deploy 28 days after launch. But we may only have a slim two day observation window for LightSail between deployment and reentry.

A deployment of LightSail 28 days after launch would put it in the June 16th timeframe.

“That’s the nominal mission time, yes,” Davis told Universe Today. “Our orbital models predict 2-10 days. For our 2016 flight, the mission will last at least four months.”

The Planetary Society plans to have a live ‘mission control center’ to track LightSail after P-POD deployment, complete with a Google Map showing pass predictions.

Satellite spotting can be a fun and addictive pastime, where part of the fun is sleuthing out what you’re seeing. Hey, some relics of space history such as the early Vanguards, Telstars, and Canada’s first satellite Alouette-1 are still up there! Nabbing these photographically are as simple as plopping your DSLR on a tripod, setting the focus and doing a time exposure as the satellite passes by.

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The X-37B undergoing encapsulation in preparation for launch. Image credit: USAF

Here’s to smooth solar sailing and clear skies as we embark on our quest to track down the X-37B and LightSail-1 in orbit.

-Follow us as @Astroguyz on Twitter, as we’ll be providing further info on orbits and visibility passes as they are made public.

Weekly Space Hangout – May 8, 2015: Emily Rice & Brian Levine from Astronomy on Tap

Host: Fraser Cain (@fcain)
Special Guest: Emily Rice & Brian Levine from Astronomy on Tap

Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Charles Black (@charlesblack / sen.com/charles-black)
Brian Koberlein (@briankoberlein)
Dave Dickinson (@astroguyz / www.astroguyz.com)
Continue reading “Weekly Space Hangout – May 8, 2015: Emily Rice & Brian Levine from Astronomy on Tap”

To The Moon! Crowdfunded Solar Sail Shoots For Lunar Launch

It’s a tiny satellite with ambitious goals: to zip all the way from the Earth to the Moon using a solar sail. A typical “cubesat” satellite sticks around Earth’s orbit to do a science, but the team behind Lunarsail convinced dozens of crowfunding donors that their concept can go even further.

The team asked for $11,000 on Kickstarter and actually received more than $15,000. The next step is to submit a formal proposal to NASA to hitch a ride on a rocket and get into space. (An announcement of opportunity was on NASA’s website in mid-August, but the link is currently unavailable as the agency’s site is shut down amid the government furlough. The posted deadline was Nov. 26).

“Common sense seems to suggest that cubesats don’t have the power or the huge rocket they would need to reach the Moon. Common sense can be deceptive, though,” the team wrote on their crowdfunding campaign page.

NCube-2 cubesat, a typical configuration for this kind of satellite (although the outer skin is missing.) Credit: ARES Institute
NCube-2 cubesat, a typical configuration for this kind of satellite (although the outer skin is missing.) Credit: ARES Institute

“It doesn’t take a more powerful spacecraft … the satellite doesn’t care what orbit it’s in — it just does its thing. It also doesn’t require a more powerful rocket. All we need is a rocket powerful enough to put the spacecraft into an appropriate orbit around the Earth, and then we can take over and get ourselves to the Moon.”

The Aerospace Research & Engineering Systems (ARES) Institute, which is the entity behind Lunarsail, further plans to involve students in the campaign. It’s asking around to see if there are any interested parties who could “bring mission-related science activities to thousands of students, particularly those in minority and at-risk communities.” If this goes forward, students could participate through experiments, observations and also with mobile apps.

While the team acknowledges it takes time to get a concept on a rocket and into space, they have a goal of having everything “flight-ready” by December 2016. Follow updates on the project at its web page.

Huge Solar Sail Portion Unfurls In Crucial Ground Test

We’re sure the people in that picture above must have had sweaty hands as they unfurled a huge solar sail in front of the camera. What you’re seeing there is a crucial ground test in which a quarter of Sunjammer — the largest solar sail ever expected to fly — was unfurled under Earth gravity conditions Monday (Sept. 30).

Sunjammer is expected to launch in January 2015, a slight delay from an earlier projection of November 2014. This test took place under even tougher conditions than the sail will face in space, as there will be no atmosphere and it will be operating in microgravity, officials said.

According to the team (which included prime contractor L’Garde Inc., NASA and Space Services Inc.), everything went well.

Sunjammer team members stand behind their solar sail. Credit: sunjammermission.com
Sunjammer team members stand behind their solar sail. Credit: sunjammermission.com

“If this test succeeded under these stressing conditions, we certainly anticipate it will work exceedingly well in space,” stated Nathan Barnes, L’Garde president.

Solar sails could one day be an alternative to conventional propellant-based spacecraft, providing that the spacecraft roam close enough to the sun to receive photonic pressure to do their maneuvers. There have been decades of development on the ground, but the first solar sail test took place in 2010 when Japan unfurled its IKAROS solar sail successfully.

Sunjammer, which would be NASA’s first solar sail in space, will look at solar activity. You can read more about the mission on its official website.

Source: Sunjammer

NASA to Test New Solar Sail Technology

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Solar sails, much like anti-matter and ion engines appear at first glance to only exist in science fiction. Many technologies from science fiction however, become science fact.

In the example of solar sails, perfecting the technology would allow spacecraft to travel through our solar system using very little fuel.

NASA has been making strides with solar sail technology. Using the NanoSail-D mission, NASA continues to gather valuable data on how well solar sails perform in space. The Planetary Society will also be testing solar sail technology with their LightSail-1 project sometime next year.

How will NASA (and others) test solar sail technology, and develop it into a common, reliable technology?

The second of three recently announced technology demonstrations, The Solar Sail Demonstration, will test the deployment of a solar sail in space along with testing attitude control. The solar sail will also execute a navigation sequence with mission-capable accuracy.

In order to make science fiction into reality, NASA engineers are testing solar sails that could one day provide the propulsion for deep space missions. Spacecraft using solar sails would travel in our solar system in a similar manner to a sailboat through water, except spacecraft using solar sails would rely on sunlight instead of wind. A spacecraft propelled by a solar sail would use the sail to capture photons emitted from the Sun. Over time, the buildup of the solar photons provides enough thrust for a small spacecraft to travel in space.

NASA’s solar sail demonstration mission will deploy and operate a sail area 7 times larger than ever flown in space. The technology used in the demonstration will be applicable to many future space missions, including use in space weather warning systems to provide timely and accurate warnings of solar flare activity. The solar sail demonstration is a collaborative effort between The National Oceanic and Atmospheric Administration (NOAA), NASA and contractor L’Garde Inc.

NASA lists several capabilities solar sails have to offer, such as:

  • Orbital Debris: Orbital debris can be captured and removed from orbit over a period of years using the small solar-sail thrust.
  • De-orbit of spent satellites: Solar sails can be integrated into satellite payloads so that the satellite can be de-orbited at the end of its mission.
  • Station keeping: Using the low propellantless thrust of a solar sail to provide station keeping for unstable in-space locations.
  • Deep space propulsion: Payloads free of the Earth’s pull can be continuously and efficiently accelerated to the other planets, or out of the solar system, such as proposed in Project Encounter.
  • As an example, the GeoStorm project considers locating solar storm warning satellites at pseudo Lagrange points three times further from the Earth by using the solar sail to cancel some solar gravitational pull, thus increasing warning time from ~15 minutes to ~45 minutes.

    Providing a satellite with a persistent view of northern or southern latitudes, i.e., a “pole-sitter” project. This allows the observational advantages of today’s geosynchronous satellites for orbits with view angles of the northern and southern high-latitudes.

    A solar sail system, measuring 66 feet on each side was tested in 2005 in the world's largest vacuum chamber. Image Credit: NASA

    If you’d like to learn more about solar sails, Caltech has a nice “Solar Sailing 101” page at: http://www.ugcs.caltech.edu/~diedrich/solarsails/intro/intro.html

    Source: NASA Technology Demonstration Mission Updates

    Last & Best Chances to See NanoSail-D

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    Over the next few weeks, skywatchers will have excellent viewing opportunities for the NanoSail-D solar sail.

    The satellite is coming to the end of its 95-day mission to test the viability of de-orbiting decommissioned satellites or space debris. NanoSail-D is now de-orbiting and slowly losing altitude in the Earths thin upper atmosphere.

    As the satellite descends, viewing opportunities will improve.

    To see NanoSail-D pass over, you will need to know exactly when it will be visible from your location. To do this, go to Heavens-above.com or Spaceweather.com where star charts with times and pass details will be displayed after you enter your observing site.

    Once you know the time and location in the sky of the pass of the satellite, make sure you are able to get a good view of the part of the sky where the satellite due to appear. Give yourself plenty of time, go outside and get ready. I always set a 30 second reminder on my watch or cell phone, so I don’t have to fumble around or guess the time.

    To enjoy the NanoSail-D passes:

    • Make sure you know the right place in the sky and the time of the pass, by checking on the web.
    • Make sure you will be able to get a clear view of it from your viewing location.
    • Set an alarm or get ready for the pass as it only lasts a few seconds.
    • NASA expects NanoSail-D to stay in orbit through May 2011.
    • If you are an astrophotographer, don’t forget, NASA and SpaceWeather.com are having an imaging contest of NanoSail-D. Find out more here.
    • Most of all, get your friends and family outside with you to watch NanoSail-D and enjoy!

    Artist concept of Nanosail-D in Earth orbit. Credit: NASA