Hunting LightSail in Orbit

. Credit: Planetary Society

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.

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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.

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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.

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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

Jolene Creighton (@jolene723 /
Charles Black (@charlesblack /
Brian Koberlein (@briankoberlein)
Dave Dickinson (@astroguyz /
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

This Lunarsail concept from the Aerospace Research and Engineering Systems Institute successfully met its crowdfunding goal and is applying to get on a NASA rocket in the next few years. Source: Kickstarter (screenshot)

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

A view of the world's largest solar sail, Sunjammer. Credit:

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

“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

The Solar Sail demonstration mission. Credit: NASA

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:

    Source: NASA Technology Demonstration Mission Updates

    Last & Best Chances to See NanoSail-D

    Nanosail-D Pass Credit: Vesa Vauhkonen,


    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 or 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 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

    Success! NanoSail-D Deploys

    We have a solar sail! As we reported on the 19th, the little cubesat that was thought to be lost has now been found, and now today, Friday, Jan. 21, engineers at NASA’s Marshall Space Flight Center confirmed that the NanoSail-D deployed its 100-square-foot polymer solar sail in low-Earth orbit and is operating as planned. The sail actually deployed late on Jan. 20, and it was quite interesting to see how ham radio operators were helping the engineers monitor the critical beacons sent out by the spacecraft — with communications also being sent back and forth via Twitter. The video above is from Henk Hamoen (@PA3GUO on Twitter) who operates a ham radio station in the Netherlands. The NanoSail-D sends an beacon packet every 10 seconds, which contains data about the spacecraft systems operation, and Hamoen and others were able to help make sure things were going as planned.

    Continue reading “Success! NanoSail-D Deploys”

    Separation Camera Takes Full Images and ‘Movie’ of IKAROS Solar Sail

    Image of the fully deployed IKAROS solar sail, taken by a separation camera. Credit: JAXA


    Two small “separation cameras” were ejected from JAXA’s (Japan Aerospace Exploration Agency) IKAROS solar sail, which successfully took some amazing full images of the fully deployed sail. The cameras are quite small, cylindrical in shape about 6 cm in diameter and height. They were ejected from the sail using a spring, and then they looked back at IKAROS, and relayed the images wirelessly. The cameras are now floating off into space, having done their job of taking these images. Below, an animation, or movie made by combining several images.

    An animation created from several pictures taken by the DCAM2 on IKAROS. The camera rotated as it was ejected from the solar sail, so it is rotating, not IKAROS. Credit: JAXA

    From the JAXA press release:

    We will measure and observe the power generation status of the thin film solar cells, accelerate the satellite by photon pressure, and verify the orbit control through that acceleration. Through these activities, we will ultimately aim at acquiring navigation technology through the solar sail.

    So, now that we know the sail is fully deployed, next comes the big test of whether solar sailing will actually work. This is huge, to finally have the opportunity to test a solar sail in space.

    Close-up of the middle of the IKAROS solar sail, taken by the DCAM2. Credit: JAXA

    From the IKAROS blog, speaking as the cameras:

    Unfortunately I only have the battery, and…working time is very short for about 15 minutes after I do my best work is a planets around the Sun, the world’s smallest man-made flying with IKAROS continue.

    Translation: these tiny cameras only had about 15 minutes to do their job of taking pictures before becoming dead little satellites orbiting around the sun.

    IKAROS was launched on May 21, 2010 from the Tanegashima Space Center in Japan.

    We’ll keep you posted as JAXA begins testing the solar sail.

    IKAROS graphic of how the sail deployed. Credit: JAXA

    Japanese Solar Sail Deploys Successfully

    An image from IKAROS, showing the completion of the second stage deployment of the solar sail. Credit: JAXA


    New images and data from the IKAROS solar sail show the thin solar film has deployed and expanded successfully and is now generating power. Since its launch on May 21, 2010, teams from the Japan Aerospace Exploration Agency (JAXA), have been painstakingly checking out all the systems on IKAROS before deploying the sail, and even the process of unfurling the sail had been a slow process. JAXA began to deploy the sail on June 3, analyzing each step before proceeding. Yesterday, JAXA released a photo of a partially deployed sail (below), but didn’t offer much information as far as the status. But they now have confirmed that the sail was successfully expanded and is generating power. IKAROS is now about 7.7 million km from Earth.

    In the image above, the harness is an electrical connection between the membrane and the main body, and the tether is the mechanical connection between the membrane and the main body.

    And now comes the big test of the solar sail: will it provide the ability to navigate the spacecraft?

    “We will measure and observe the power generation status of the thin film solar cells, accelerate the satellite by photon pressure, and verify the orbit control through that acceleration,” JAXA said in a press release. “Through these activities, we will ultimately aim at acquiring navigation technology through the solar sail.”

    The craft will head towards Venus, and the exciting part will be finding out how fast and accurate the solar sail can fly.

    Partial deploy of IKAROS, the first stage. Credit: JAXA

    From the IKAROS blog (translated from Japanese):

    First, the spin rate and learned that he had first IKAROS have successfully deployed from the attitude data. Then, I was part of the downlink data captured with the camera image monitor confirmed that the sail has been deployed from the image. On June 10 has been expanded to clean the sail, “stretched states” get the picture, confirmed the successful deployment of the sail after deployment finished the second check.

    Also check the power of solar cells was carried out together, we achieved minimum success!

    Power will be realized with the world’s first solar powered sail development.

    Graphic showing the sail in full deployment. Credit: JAXA

    See the IKAROS webpage for more info and detailed graphics.

    Sources: JAXA, IKAROS blog

    Planetary Society to Launch Three Separate Solar Sails

    LightSail-1 Artists rendition of LightSail-1 by Rick Sternbach. Credit: Planetary Society

    On the 75th anniversary of astronomer Carl Sagan’s birth, the Planetary Society announced their plans to sail a spacecraft on sunlight alone by the end of 2010. Called LightSail, the project will launch three separate spacecraft over the course of several years, beginning with LightSail-1, which will demonstrate that sunlight alone can propel a spacecraft in Earth orbit. LightSails 2 and 3, will travel farther into space.

    Sagan, co-founder of the Planetary Society was a long-time advocate of solar sailing.

    LightSail-1 Prior to Sail Deployment Credit: Planetary Society
    LightSail-1 Prior to Sail Deployment Credit: Planetary Society

    Lightsail-1 will fit into a volume of just three liters before the sails unfurl to fly on sunlight.

    On today’s 365 Days of Astronomy podcast, Sagan’s widow and collaborator, Ann Druyan said this project is a “Wright Brothers Kitty Hawk-type” enterprise of inventing and proving a new way of moving through the cosmos.

    “On one episode of Cosmos, we wrote ‘We have lingered too long on the shores of the cosmic ocean. It’s time to set sail for the stars,'” she said. “And that’s what I was thinking when it became clear that we had the resources to mount this expedition, that we are serious at The Planetary Society. And at Cosmos Studios, my company which provided the principal support for the first 10 years of this project, we’re really serious about giving our kids a future in which science and technology is used in its most wise and benign and forward-looking possible way. That’s why I’m so thrilled and I just think if Carl were alive he would have been absolutely overcome at the notion that The Planetary Society is mounting its own space program, let alone its own launch.”

    The solar sail project was boosted by a one-million-dollar anonymous donation.

    Taking advantage of the technological advances in micro- and nano-spacecraft over the past five years, The Planetary Society will build LightSail-1 with three Cubesat spacecraft. One Cubesat will form the central electronics and control module, and two additional Cubesats will house the solar sail module. Cameras, additional sensors, and a control system will be added to the basic Cubesat electronics bus.

    Reflected light pressure, not the solar wind, propels solar sails. The push of photons against a mirror-bright surface can continuously change orbital energy and spacecraft velocity. LightSail-1 will have four triangular sails, arranged in a diamond shape resembling a giant kite. Constructed of 32 square meters of mylar, LightSail-1 will be placed in an orbit over 800 kilometers above Earth, high enough to escape the drag of Earth’s uppermost atmosphere. At that altitude the spacecraft will be subject only to the force of gravity keeping it in orbit and the pressure of sunlight on its sails increasing the orbital energy.

    Lightsail-2 will demonstrate a longer duration flight to higher Earth orbits. LightSail-3 will go to the Sun-Earth Libration Point, L1, where solar sails could be permanently placed as solar weather stations, monitoring the geomagnetic storms from the Sun that potentially endanger electrical grids and satellite systems around Earth.

    The Planetary Society’s attempt in 2005 to launch the world’s first solar sail, Cosmos 1, was scuttled when its launch vehicle, a Russian Volna rocket, failed to reach Earth orbit.

    For more information, see the Planetary Society’s LightSail Page.