The Indian Space Research Organization (ISRO) has made immense progress since the turn of the century. From its humble beginnings, launching satellites into orbit between 1975 and 2000, the ISRO sent their first mission to the Moon in October of 2008 (the Chandrayaan-1 orbiter), followed by their first mission to Mars – the Mars Orbiter Mission (MOM) – in November of 2013.
And in the coming years, the ISRO intends to become the fourth space agency to send astronauts into space. In so doing, they will join an exclusive club of space agencies that consists of only Russia, the United States and China. Last week (on September 7th, 2018) the organization unveiled the spacesuit that their astronauts will be wearing when they make this historic journey.
After almost seventy years of spaceflight, space debris has become a rather serious problem. This junk, which floats around in Low Earth Orbit (LEO), consists of the spent first rocket stages and non-functioning satellites and poses a major threat to long-term missions like the International Space Station and future space launches. And according to numbers released by the Space Debris Office at the European Space Operations Center (ESOC), the problem is only getting worse.
In addition, space agencies and private aerospace companies hope to launch considerably more in the way of satellites and space habitats in the coming years. As such, NASA has begun experimenting with a revolutionary new idea for removing space debris. It is known as the RemoveDebris spacecraft, which recently deployed from the ISS to conduct a series of Active Debris Removal (ADR) technology demonstrations.
This satellite was assembled by Surrey Satellite Technology Ltd. and the Surrey Space Center (at the University of Surrey in the UK) and contains experiments provided by multiple European aerospace companies. It measures roughly 1 meter (3 feet) on a side and weighs about 100 kg (220 lbs), making it the largest satellite deployed to the ISS to date.
The purpose of the RemoveDebris spacecraft is to demonstrate the effectiveness of debris nets and harpoons at capturing and removing space debris from orbit. As Sir Martin Sweeting, the Chief Executive of SSTL, said in a recent statement:
“SSTL’s expertise in designing and building low cost, small satellite missions has been fundamental to the success of RemoveDEBRIS, a landmark technology demonstrator for Active Debris Removal missions that will begin a new era of space junk clearance in Earth’s orbit.”
Aside from the Surrey Space Center and SSTL, the consortium behind the RemoveDebris spacecraft includes Airbus Defense and Space – the world’s second largest space company – Airbus Safran Launchers, Innovative Solutions in Space (ISIS), CSEM, Inria, and Stellenbosch University. The spacecraft, according to the Surrey Space Center’s website, consists of the following:
“The mission will comprise of a main satellite platform (~100kg) that once in orbit will deploy two CubeSats as artificial debris targets to demonstrate some of the technologies (net capture, harpoon capture, vision-based navigation, dragsail de-orbitation). The project is co-funded by the European Commission and the project partners, and is led by the Surrey Space Centre (SSC), University of Surrey, UK.”
For the sake of the demonstration, the “mothership” will deploy two cubesates which will simulate two pieces of space junk. For the first experiment, one of the CubeSats – designated DebrisSat 1 – will inflate its onboard balloon in order to simulate a larger piece of junk. The RemoveDebris spacecraft will then deploy its net to capture it, then guide it into the Earth’s atmosphere where the net will be released.
The second CubeSat, named DebrisSat 2, will be used to test the mothership’s tracking and ranging lasers, its algorithms, and its vision-based navigation technology. The third experiment, which will test the harpoon’s ability to capture orbiting space debris, is set to take place next March. For legal reasons, the harpoon will not be tested on an actual satellite, and will instead consist of the mothership extending an arm with a target on the end.
The harpoon will then be fired on a tether at 20 meters per second (45 mph) to tests it accuracy. After being launched to the station back on April 2nd, the satellite was deployed from the ISS’ Japanese Kibo lab module on June 20th by the stations’ Canadian robotic arm. As Guillermo Aglietti, the director of the Surrey Space Center, explained in an interview with SpaceFlight Now before the spacecraft was launched to the ISS:
“The net, as a way to capture debris, is a very flexible option because even if the debris is spinning, or has got an irregular shape, to capture it with a net is relatively low-risk compared to … going with a robotic arm, because if the debris is spinning very fast, and you try to capture it with a robotic arm, then clearly there is a problem. In addition, if you are to capture the debris with a robotic arm or a gripper, you need somewhere you can grab hold of your piece of debris without breaking off just a chunk of it.”
The net experiment is currently scheduled for September of 2018 while the second experiment is scheduled for October. When these experiments are complete, the mothership will deploy its dragsail to act as a braking mechanism. This expandable sail will experience collisions with air molecules in the Earth’s outer atmosphere, gradually reducing its orbit until it enters the denser layers of Earth’s atmosphere and burns up.
This sail will ensure that the spacecraft deorbits within eights weeks of its deployment, rather than the estimated two-and-half years it would take to happen naturally. In this respect, the RemoveDebris spacecraft will demonstrate that it is capable of tackling the problem of space debris while not adding to it.
In the end, the RemoveDebris spacecraft will test a number of key technologies designed to make orbital debris removal as simple and cost-effective as possible. If it proves effective, the ISS could be receiving multiple RemoveDebris spacecraft in the ftureu, which could then be deployed gradually to remove larger pieces of space debris that threaten the station and operational satellites.
Conor Brown is the external payloads manager of Nanoracks LLC, the company that developed the Kaber system aboard the Kibo lab module to accommodate the increasing number of MicroSats being deployed from the ISS. As he expressed in a recent statement:
“It’s wonderful to have helped facilitate this ground-breaking mission. RemoveDebris is demonstrating some extremely exciting active debris removal technologies that could have a major impact to how we manage space debris moving forward. This program is an excellent example of how small satellite capabilities have grown and how the space station can serve as a platform for missions of this scale. We’re all excited to see the results of the experiments and impact this project may have in the coming years.”
In addition to the RemoveDebris spacecraft, the ISS recently received a new tool for detecting space debris. This is known as the Space Debris Sensor (SDS), a calibrated impact sensor mounted on the exterior of the station to monitor impacts caused by small-scale space debris. Coupled with technologies designed to clean up space debris, improved monitoring will ensure that the commercialization (and perhaps even colonization) of LEO can begin.
Orbital debris (aka. space junk) is one of the greatest problems facing space agencies today. After sixty years of sending rockets, boosters and satellites into space, the situation in the Low Earth Orbit (LEO) has become rather crowded. Given how fast debris in orbit can travel, even the tiniest bits of junk can pose a major threat to the International Space Station and threaten still-active satellites.
It’s little wonder then why ever major space agency on the planet is committed to monitoring orbital debris and creating countermeasures for it. So far, proposals have ranged from giant magnets and nets and harpoons to lasers. Given their growing presence in space, China is also considering developing giant space-based lasers as a possible means for combating junk in orbit.
For the sake of their study, the team conducted numerical simulations to see if an orbital station with a high-powered pulsed laser could make a dent in orbital debris. Based on their assessments of the velocity and trajectories of space junk, they found that an orbiting laser that had the same Right Ascension of Ascending Node (RAAN) as the debris itself would be effective at removing it. As they state in their paper:
“The simulation results show that, debris removal is affected by inclination and RAAN, and laser station with the same inclination and RAAN as debris has the highest removal efficiency. It provides necessary theoretical basis for the deployment of space-based laser station and the further application of space debris removal by using space-based laser.”
This is not the first time that directed-energy has been considered as a possible means of removing space debris. However, the fact that China is investigating directed-energy for the sake of debris removal is an indication of the nation’s growing presence in space. It also seems appropriate since China is considered to be one of the worst offenders when to comes to producing space junk.
Back in 2007, China conducted a anti-satellite missile test that resulted in the creation over 3000 of bits of dangerous debris. This debris cloud was the largest ever tracked, and caused significant damage to a Russian satellite in 2013. Much of this debris will remain in orbit for decades, posing a significant threat to satellites, the ISS and other objects in LEO.
Of course, there are those who fear that the deployment of lasers to LEO will mean the militarization of space. In accordance with the 1966 Outer Space Treaty, which was designed to ensure that the space exploration did not become the latest front in the Cold War, all signatories agreed to “not place nuclear weapons or other weapons of mass destruction in orbit or on celestial bodies or station them in outer space in any other manner.”
In the 1980s, China was added to the treaty and is therefore bound to its provisions. But back in March of 2017, US General John Hyten indicated in an interview with CNN that China’s attempts to develop space-based laser arrays constitutes a possible breach of this treaty:
“They’ve been building weapons, testing weapons, building weapons to operate from the Earth in space, jamming weapons, laser weapons, and they have not kept it secret. They’re building those capabilities to challenge the United States of America, to challenge our allies…We cannot allow that to happen.”
Such concerns are quite common, and represent a bit of a stumbling block when it comes to the use of directed-energy platforms in space. While orbital lasers would be immune to atmospheric interference, thus making them much more effective at removing space debris, they would also lead to fears that these lasers could be turned towards enemy satellites or stations in the event of war.
As always, space is subject to the politics of Earth. At the same time, it also presents opportunities for cooperation and mutual assistance. And since space debris represents a common problem and threatens any and all plans for the exploration of space and the colonization of LEO, cooperative efforts to address it are not only desirable but necessary.
Beginning in the 1950s with the Sputnik, Vostok and Mercury programs, human beings began to “slip the surly bonds of Earth”. And for a time, all of our missions were what is known as Low-Earth Orbit (LEO). Over time, with the Apollo missions and deep space missions involving robotic spacecraft (like the Voyager missions), we began to venture beyond, reaching the Moon and other planets of the Solar System.
But by and large, the vast majority of missions to space over the years – be they crewed or uncrewed – have been to Low-Earth Orbit. It is here that the Earth’s vast array of communications, navigation and military satellites reside. And it is here that the International Space Station (ISS) conducts its operations, which is also where the majority of crewed missions today go. So just what is LEO and why are we so intent on sending things there?
Technically, objects in low-Earth orbit are at an altitude of between 160 to 2,000 km (99 to 1200 mi) above the Earth’s surface. Any object below this altitude will being to suffer from orbital decay and will rapidly descend into the atmosphere, either burning up or crashing on the surface. Objects at this altitude also have an orbital period (i.e. the time it will take them to orbit the Earth once) of between 88 and 127 minutes.
Objects that are in a low-Earth orbit are subject to atmospheric drag since they are still within the upper layers of Earth’s atmosphere – specifically the thermosphere (80 – 500 km; 50 – 310 mi), theremopause (500–1000 km; 310–620 mi), and the exosphere (1000 km; 620 mi, and beyond). The higher the object’s orbit, the lower the 1atmospheric density and drag.
However, beyond 1000 km (620 mi), objects will be subject to Earth’s Van Allen Radiation Belts – a zone of charged particles that extends to a distance of 60,000 km from the Earth’s surface. In these belts, solar wind and cosmic rays have been trapped by Earth’s magnetic field, leading to varying levels of radiation. Hence why missions to LEO aim for attitudes between 160 to 1000 km (99 to 620 mi).
Within the thermosphere, thermopause and exosphere, atmospheric conditions vary. For instance, the lower part of the thermosphere (from 80 to 550 kilometers; 50 to 342 mi) contains the ionosphere, which is so-named because it is here in the atmosphere that particles are ionized by solar radiation. As a result, any spacecraft orbiting within this part of the atmosphere must be able to withstand the levels of UV and hard ion radiation.
Temperatures in this region also increase with height, which is due to the extremely low density of its molecules. So while temperatures in the thermosphere can rise as high as 1500 °C (2700 °F), the spacing of the gas molecules means that it would not feel hot to a human who was in direct contact with the air. It is also at this altitude that the phenomena known as Aurora Borealis and Aurara Australis are known to take place.
The Exosphere, which is outermost layer of the Earth’s atmosphere, extends from the exobase and merges with the emptiness of outer space, where there is no atmosphere. This layer is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide (which are closer to the exobase).
In order to maintain a Low-Earth Orbit, an object must have a sufficient orbital velocity. For objects at an altitude of 150 km and above, an orbital velocity of 7.8 km (4.84 mi) per second (28,130 km/h; 17,480 mph) must be maintained. This is slightly less than the escape velocity needed to get into orbit, which is 11.3 kilometers (7 miles) per second (40,680 km/h; 25277 mph).
Despite the fact that the pull of gravity in LEO is not significantly less than on the surface of Earth (approximately 90%), people and objects in orbit are in a constant state of freefall, which creates the feeling of weightlessness.
Uses of LEO:
In this history of space exploration, the vast majority of human missions have been to Low Earth Orbit. The International Space Station also orbits in LEO, between an altitude of 320 and 380 km (200 and 240 mi). And LEO is where the majority of artificial satellites are deployed and maintained. The reasons for this are quite simple.
For one, the deployment of rockets and space shuttles to altitudes above 1000 km (610 mi) would require significantly more fuel. And within LEO, communications and navigation satellites, as well as space missions, experience high bandwidth and low communication time lag (aka. latency).
For Earth observation and spy satellites, LEO is still low enough to get a good look at the surface of Earth and resolve large objects and weather patterns on the surface. The altitude also allows for rapid orbital periods (a little over one hour to two hours long), which allows them to be able to view the same region on the surface multiple times in a single day.
And of course, at altitudes between 160 and 1000 km from the Earth’s surface, objects are not subject to the intense radiation of the Van Allen Belts. In short, LEO is the simplest, cheapest and safest location for the deployment of satellites, space stations, and crewed space missions.
Issues with Space Debris:
Because of its popularity as a destinations for satellites and space missions, and with increases in space launches over the past few decades, LEO is also becoming increasingly congested with space debris. This takes the form of discarded rocket stages, non-functioning satellites, and debris created by collisions between large pieces of debris.
The existence of this debris field in LEO has led to growing concern in recent years, since collisions at high-velocities can be catastrophic for space missions. And with every collision, additional debris is created, creating a destructive cycle known as the Kessler Effect – which is named after NASA scientist Donald J. Kessler, who first proposed it in 1978.
In 2013, NASA estimated that there may be as much as 21,000 bits of junk bigger than 10 cm, 500,000 particles between 1 and 10 cm, and more than 100 million smaller than 1 cm. As a result, in recent decades, numerous measures have been taken to monitor, prevent, and mitigate space debris and collisions.
For instance, in 1995, NASA became the first space agency in the world to issue a set of comprehensive guidelines on how to mitigate orbital debris. In 1997, the U.S. Government responded by developing the Orbital Debris Mitigation Standard Practices, based on the NASA guidelines.
NASA has also established the Orbital Debris Program Office, which coordinates with other federal departments to monitor space debris and deal with disruptions caused by collisions. In addition, the US Space Surveillance Network currently monitors some 8,000 orbiting objects that are considered collision hazards, and provides a continuous flow of orbit data to various agencies.
The European Space Agency’s (ESA) Space Debris Office also maintains the Database and Information System Characterizing Objects in Space (DISCOS), which provides information on launch details, orbital histories, physical properties and mission descriptions for all objects currently being tracked by the ESA. This database is internationally recognized and is used by almost 40 agencies, organizations and companies worldwide.
For over 70 years, Low-Earth Orbit has been the playground of human space capability. On occasion, we have ventured beyond the playground and farther out into the Solar System (and even beyond). In the coming decades, a great deal more activity is expected to take place in LEO, which includes the deployment of more satellites, cubesats, continued operations aboard the ISS, and even aerospace tourism.
Needless to say, this increase in activity will require that we do something about all the junk permeating the space lanes. With more space agencies, private aerospace companies, and other participants looking to take advantage of LEO, some serious cleanup will need to take place. And some additional protocols will surely need to be developed to make sure it stays clean.
The Earth’s atmosphere is a total drag, especially if you’re trying to orbit our planet. So how low can you go?
The Earth’s atmosphere is a total drag, especially if you’re trying to orbit our planet. It’s a drag. Get it? Atmospheric drag. Drag. Drag.
Hi, my name is Fraser Cain. I’m the publisher of Universe Today, and sometimes my team lets me write my own jokes.
I could have started off this episode with a reference to the “Adama Drop” in-atmosphere viper deployment from BSG, but instead I went with a Dad joke. My punishment is drawing attention to it.
So how low can you go? And if you go low enough, will Ludacris appear in the mirror?
We all appreciate the Earth’s atmosphere and everything it does for you. With all the breathing, and the staying warm and the not having horrible bruises all over your body from teeny space rocks pummeling us.
I’ve got an alternative view. The Earth’s atmosphere is your gilded pressurized oxygenated cage, and it’s the one thing keeping you from flying in space.And as we all know, this is your destiny.
Without the atmosphere, you could easily orbit the Earth, a few kilometers over its surface. Traveling around and around the planet like a person sized Moon. Wouldn’t that be great?
Well, it’s not going to happen. As you walk through the atmosphere, you bonk into all the air molecules. You don’t feel it when you’re moving at walking speed, but go faster, like an airplane, and it’ll rock you like a hurricane.
Without constant thrust pushing against the atmosphere, you’ll keep slowing down, and when you’re trying to orbit the planet, it’s a killer. Our atmosphere is like someone is constantly pushing the brakes on the fly in space party.
If you’ve played Kerbal Space Program, you know the faster you’re traveling, the higher you orbit. Conversely, the slower you travel, the lower you orbit. Travel slow enough and you’ll eat it, and by it, I meant as much planet as you can co-exist with after a high speed impact.
Being more massive means more momentum to push against the atmospheric drag. But with a large surface area, it acts like a parachute, slowing you down.
Hey, I know something that’s super massive with a huge surface area. The International Space Station orbits the planet at an altitude between 330 km and 435 km.
Why such a big range? The atmosphere is constantly pushing against the ISS as it orbits the planet. This slows down the space station’s speed and lowers its orbit. It wouldn’t last more than a couple of years if it wasn’t able to counteract the atmospheric drag.
Fortunately, the station has rockets to increase its speed, and a faster speed means a higher orbit. It can even get assistance from docked spacecraft. If the space station were to go any lower, it would require higher and higher amounts of thrust to prevent re-entry into the Earth’s atmosphere.
So what are the limits? Anything below 160 km altitude will essentially re-enter almost immediately, as it’s buffeted by the thicker atmosphere. You really wouldn’t last more than a few hours at that altitude, but above 800 km you could orbit for more than 100 years.
Geosynchronous satellites that orbit the Earth and transmit our television signals are at an altitude of about 42,000 km. Satellites that high are never coming back down. Well, maybe not never.
Want to enjoy your orbital experience? Make sure you get yourself to an altitude of at least 300 km, 400 km just to be safe. You should shoot for more like 800 km if you just don’t want to worry about things for a while.
Knowing these risks, would you be willing to travel to orbit with current technology? Tell us in the comments below.
Astronauts aboard the International Space Station are going to be getting an addition in the near future, and in the form of an inflatable room no less. The Bigelow Expandable Activity Module (BEAM) is the first privately-built space habitat that will added to the ISS, and it will be transported into orbit aboard a Space X Falcon 9 rocket sometime next year.
“The BEAM is one small step for Bigelow Aerospace,” Bigelow representative Michael Gold told Universe Today, “but is also one giant leap for private sector space activities since the BEAM will be the first privately owned and developed module ever to be part of a crewed system in space.”
NASA and Bigelow Aerospace announced the $17.8 million contract in 2013, and on October 2, 2014, Gold announced at the International Astronautical Congress that the launch would take place next year on a SpaceX resupply flight. Gold said BEAM provides an example of what the company, and private firms in general, can do in low-Earth orbit (LEO).
Upon arrival, the BEAM will be installed by the robotic Canadarm2 onto the Tranquility node’s aft docking port. Once it’s expanded, an ISS crew member will enter the module and become the first astronaut to step inside an expandable habitat system. The plan is to have the module remain in place for a few years to test and demonstrate the feasibility of the company’s inflatable space habitat technology.
The BEAM, which weighs approximately 1,360 kg (3000 lbs), will travel aboard the unpressurized cargo hold of a Dragon capsule. Once it is successfully transferred to the station, ISS astronauts will activate the deployment sequence, and the module will expand out to its full size – approx. 4 meters (13 feet) in length and 3 meters (10.5 feet) in diameter.
Bigelow currently has two stand-alone autonomous spacecraft in orbit, the Genesis I and the Genesis II – both of which are collecting data about LEO conditions and how well the technology performs in practice in space. In turn, NASA will use BEAM to measure the radiation levels inside the module as compared to other areas of the ISS to determine how safe it is for habitation.
“Through the flight of the Bigelow module on the International Space Station, we expect to learn critical technical performance data related to non-metallic structures in space,” said Jason Crusan, director of Advanced Exploration Systems Division at NASA Human Exploration and Operations Mission Directorate, in an email to Universe Today. “Data about things such as radiation, thermal, and overall operations of non-metallic structures in space has multiple benefits both to NASA and to the commercial sector.”
The BEAM module will also allow for further data collection for the company, which is planning on launching its own space station, named Bigelow Aerospace Alpha Station, to be at least partially operational as early as next year. This station will be initially made up of two BA 330 expandable habitats, which are designed to function either as an independent space station or as modular components that can be connected to create a larger apparatus.
Bigelow hopes that such stations will allow for greater participation in space exploration and research, both by nations and private companies. But looking to the future, Bigelow also sees BEAM and its other long-term projects for space habitation as a crucial step in the commercialization of Low-Earth Orbit.
Already, the company is planing on getaways that will take tourists into orbit – for a modest price, of course. Beginning in 2012, the company began offering space travel packages, including the trip to and from LEO aboard a SpaceX craft, starting at $26.25 million and a two-month stay package aboard the Alpha Station for $25 million – bringing the grand total to just $51.25 million, compared to the $40 million it currently costs members of the public to stay on the ISS for a week.
The full scale CST-100 mockup was unveiled at an invitation only ceremony for Boeing executives and media held inside a newly renovated shuttle era facility at the Kennedy Space Center where the capsule would start being manufactured later this year.
Universe Today was invited to tour the capsule for a first hand inspection of the CST-100’s interior and exterior and presents my photo gallery here.
The CST-100 is a privately built manrated capsule being developed with funding from NASA under the auspices of the agency’s Commercial Crew Program (CCP) in a public/private partnership between NASA and private industry.
The vehicle will be assembled inside the refurbished processing hangar known during the shuttle era as Orbiter Processing Facility-3 (OPF-3). Boeing is leasing the site from Space Florida.
Boeing is one of three American aerospace firms vying for a NASA contract to build an American ‘space taxi’ to ferry US astronauts to the space station and back as soon as 2017.
NASA will award one or more contracts to build Americas next human rated spaceship in August or September.
Since the forced shutdown of NASA’s Space Shuttle program following its final flight in 2011, US astronauts have been 100% dependent on the Russians and their cramped but effective Soyuz capsule for rides to the station and back – at a cost exceeding $70 million per seat.
Chris Ferguson, the final shuttle commander for NASA’s last shuttle flight (STS-135) now serves as director of Boeing’s Crew and Mission Operations.
Ferguson and the Boeing team are determined to get Americans back into space from American soil with American rockets.
Read my exclusive, in depth one-on-one interviews with Chris Ferguson – America’s last shuttle commander – about the CST-100; here and here.
The vehicle includes five recliner seats, a hatch and windows, the pilots control console with several attached Samsung tablets for crew interfaces with wireless internet, a docking port to the ISS and ample space for 220 kilograms of cargo storage of an array of equipment, gear and science experiments depending on NASA’s allotment choices.
The interior features Boeing’s LED Sky Lighting with an adjustable blue hue based on its 787 Dreamliner airplanes to enhance the ambience for the crew.
The reusable capsule will launch atop a man rated United Launch Alliance (ULA) Atlas V rocket.
Stay tuned here for Ken’s continuing Boeing, SpaceX, Orbital Sciences, commercial space, Orion, Curiosity, Mars rover, MAVEN, MOM and more planetary and human spaceflight news.
As we anxiously await the arrival of a potentially rich new meteor shower this weekend, its parent comet, 209P/LINEAR, draws ever closer and brighter. Today it shines feebly at around magnitude +13.7 yet possesses a classic form with bright head and tail. It’s rapidly approaching Earth, picking up speed every night and hopefully will be bright enough to see in your telescope very soon.
The comet was discovered in Feb. 2004 by the Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) automated sky survey. Given its stellar appearance at the time of discovery it was first thought to be an asteroid, but photos taken the following month photos by Rob McNaught (Siding Spring Observatory, Australia) revealed a narrow tail. Unlike long period comets Hale-Bopp and the late Comet ISON that swing around the sun once every few thousand years or few million years, this one’s a frequent visitor, dropping by every 5.09 years.
209P/LINEAR belongs to the Jupiter family of comets, a group of comets with periods of less than 20 years whose orbits are controlled by Jupiter. When closest at perihelion, 209P/LINEAR coasts some 90 million miles from the sun; the far end of its orbit crosses that of Jupiter. Comets that ply the gravitational domain of the solar system’s largest planet occasionally get their orbits realigned. In 2012, during a relatively close pass of that planet, Jupiter perturbed 209P’s orbit, bringing the comet and its debris trails to within 280,000 miles (450,000 km) of Earth’s orbit, close enough to spark the meteor shower predicted for this Friday night/Saturday morning May 23-24.
This time around the sun, the comet itself will fly just 5.15 million miles (21 times the distance to the moon) from Earth around 3 a.m. CDT (8 hours UT) May 29 a little more than 3 weeks after perihelion, making it the 9th closest comet encounter ever observed. Given , you’d think 209P would become a bright object, perhaps even visible with the naked eye, but predictions call for it to reach about magnitude +11 at best. That means you’ll need an 8-inch telescope and dark sky to see it well. Either the comet’s very small or producing dust at a declining rate or both. Research published by Quanzhi Ye and Paul A. Wiegert describes the comet’s current dust production as low, a sign that 209P could be transitioning to a dormant comet or asteroid.
Fortunately, the moon’s out of the way this week and next when 209P/LINEAR is closest and brightest. Since we enjoy comets in part because of their unpredictability, maybe a few surprises will be in the offing including a brighter than expected appearance. The maps will help you track down 209P during the best part of its apparition. I deliberately chose ‘black stars on a white background’ for clarity in use at the telescope. It also saves on printer ink!
We’re grateful for the dust 209P/LINEAR carelessly lost during its many passes in the 19th and early 20th centuries. Earth is expected to pass through multiple filaments of debris overnight Friday May 23-24 with the peak of at least 100 meteors per hour – about as good as a typical Perseid or Geminid shower – occurring around 2 a.m. CDT (7 hours UT).
If it’s cloudy or you’re not in the sweet zone for viewing either the comet or the potential shower, astrophysicist Gianluca Masi will offer a live feed of the comet at the Virtual Telescope Project website scheduled to begin at 3 p.m. CDT (8 p.m. Greenwich Time) May 22. A second meteor shower live feed will start at 12:30 a.m. CDT (5:30 a.m. Greenwich Time) Friday night/Saturday morning May 23-24.
SLOOH will also cover 209P/LINEAR live on the Web with telescopes on the Canary Islands starting at 5 p.m. CDT (6 p.m. EDT, 4 p.m. MDT and 3 p.m. PDT) May 23. Live meteor shower coverage featuring astronomer Bob Berman of Astronomy Magazine begins at 10 p.m. CDT. Viewers can ask questions by using hashtag #slooh.
The International Space Station will have to look out for new debris from an exploded Russian rocket (NASA image)
Traveling through low-Earth orbit just got a little more dangerous; a drifting Russian Breeze M (Briz-M) rocket stage that failed to execute its final burns back on August 6 has recently exploded, sending hundreds of shattered fragments out into orbit.
Russia and the U.S. Defense Department (JFCC-Space) have stated that they are currently tracking 500 pieces of debris from the disintegrated Breeze M, although some sources are saying there are likely much more than that.
After a successful liftoff via Proton rocket on August 6 from the Baikonur Cosmodrome, the Breeze M upper stage’s engines shut off after only 7 seconds as opposed to the normal 18 minutes, leaving its fuel tanks filled with 10 to 15 tons of hydrazine and nitrogen tetroxide propellants. Its payloads, the Indonesian Telkom 3 and the Russian Express-MD2 communications satellites, were subsequently deployed into the wrong orbits as the Breeze M computer continued functioning.
Although originally expected to remain intact for at least another year, the rocket stage “violently disintegrated” on October 16. Evidence of the explosion was first observed by astronomer Robert McNaught at Australia’s Siding Springs Observatory, who counted 70 fragments visible within the narrow field-of-view telescope he was using for near-Earth asteroid observations.
The exact cause of the explosion isn’t known — it may have been sparked by an impact with another piece of space junk or the result of stresses caused by the Breeze M’s eccentric orbit, which varied in altitude from 265 to 5,015 kilometers (165 miles to 3,118 miles) with an inclination of 49.9 degrees.
This was the third such breakup of a partially-full Breeze M upper stage in orbit, the previous events having occurred in 2007 and 2010, and yet another Breeze M still remains in orbit after a failed burn in August 2011.
Most of the latest fragments are still in orbit at altitudes ranging from 250 to 5,000 km (155 to 3,100 miles), where they are expected to remain.
“Although some of the pieces have begun to re-enter, most of the debris will remain in orbit for an extended period of time.”
– Jamie Mannina, US State Department spokesperson
According to NASA the debris currently poses no immediate threat to the Space Station although the cloud is “believed not to be insignificant.” Still, according to a post on Zarya.com the Station’s course will periodically take it within the Breeze M debris cloud, and “will sometimes spend several days at a time with a large part of its orbit within the cloud.”
Source: RT.com and SpaceflightNow.com. Inset image: the Breeze M (Briz-M) upper stage which disintegrated on Oct. 16. (Khrunichev)
[/caption]Greetings, fellow SkyWatchers! It’s shaping up to be a great week to enjoy astronomy. For both hemispheres, the Virginid Meteor shower is underway and its peak occurs late Monday night / early Tuesday morning. Need more celestial fireworks? Then keep looking up as the “April Fireballs” will be visiting, with their peak beginning about a week from today and lasting for 24 days. Even if you only catch one of these bright travelers as they sparkle across the starry sky, it will make your night! But hang on, there will be plenty to explore. Bright stars and bright planets are featured – as well as some of the season’s best galaxies. Keep your telescope out and don’t get spooked, because the “Ghost of Jupiter” will be a challenge object! If you want to know more about astonomy history, and what you can see with just your eyes and your optics, then meet me in the back yard…
Monday, April 9 – Tonight let’s take a journey towards the 25th brightest star in the night sky – 1.3 magnitude, Alpha Leonis. Regulus, known as “The Little King,” is the brightest star in Leo. At 77 light-years away, this star is considered a “dwarf” despite shining with a visible light almost 150 times that of Sol. The orange-red giant Arcturus and the blue white “dwarf” Regulus both share a common absolute magnitude very close to 0. The reason the two stars shine with a similar intrinsic brightness – despite widely different physical sizes – is Regulus’ photosphere is more than twice as hot (12,000 C) as Arcturus. While observing Regulus, look for a distant companion of magnitude 8.5. Normally low powers would best concentrate the companion’s light, but try a variety of magnifications to help improve contrast. For those with large aperture scopes, look for a 13.1 magnitude “companion’s companion” a little more than 2 arc seconds away!
Tuesday, April 10 – Be sure to get up before dawn to enjoy the Virginid meteor shower. The radiant point will be near Gamma in the bowl of Virgo. The fall rate of 20 per hour is above average for meteor showers, and with the Moon partially out of the equation this morning, you’re in for a treat!
Tonight, let’s have a look at Arcturus – a star whose distance from the Earth (10 parsecs) and radial velocity (less than 200 meters per second) can almost be considered a benchmark. By skydark you will see 0.2 magnitude, Arcturus – the brightest star in Bootes and 4th brightest star in the night sky – some 30 degrees above the eastern horizon. Apparent to the eye is Arcturus’ orange color. Because a star’s intrinsic luminosity relates to its apparent brightness and distance, Arcturus’ absolute magnitude is almost precisely the same as its apparent magnitude. Just because Arcturus’ radial velocity is nearly zero doesn’t mean it isn’t on the move relative to our Sun. Arcturus is now almost as close as it will ever get and its large proper motion – perpendicular to our line of sight – exceeds 125 kilometers per second. Every 100 years Arcturus moves almost 1 degree across the sky!
Since you’ve looked at a red star, why not look at a red planet before you call it a night? Mars is still making a wonderful apparition. Have you noticed it dimming even more? Right now it should be about magnitude -0.5. You may have noticed something else about Mars in the eyepiece, too… It’s getting smaller!
Wednesday, April 11 – Today is the birthday of William Wallace Campbell. Born in 1862, Campbell went on to become the leader of stellar motion and radial velocity studies. He was the director of Lick Observatory from 1901 to 1930, and also served as president of the University of California and the National Academy of Sciences. Also born on this day – but in 1901 – was Donald H. Menzel – assistant astronomer at Lick Observatory. Menzel became Director of Harvard Observatory, an expert on the Sun’s coronosphere and held a genuine belief in the extraterrestrial nature of UFOs. Today in 1960, the first radio search for extraterrestrial civilizations was started by Frank Drake (Project Ozma). In 1986, Halley’s Comet closed within 65 million kilometers of the Earth – as close as it would get.
Tonight, why don’t we honor Campbell’s work as we try taking a look at a variable ourselves? RT (star 48) Aurigae is a bright cephid that is located roughly halfway between Epsilon Geminorum and Theta Aurigae. This perfect example of a pulsating star follows a precise timetable of 3.728 days and fluxes by close to one magnitude.
Thursday, April 12 – Today in 1961, Yuri Gagarin made one full orbit of the Earth aboard Vostok 1, while also becoming the first human in space. Also today (in 1981) Columbia became the first Space Shuttle to launch.
Break out the telescope tonight and launch your way towards Iota Cancri – a fine wide disparate double of magnitudes 4.0 and 6.6 separated by some 30 arc seconds. This true binary is so distant from one another that they take over 60,000 years to complete a single orbit around their common center of gravity! Located slightly less than a fist’s width due north of M44, this pair is about 300 light years distant. Both stars shine with a light considerably brighter than our Sun and observers may note a subtle gold and pale blue color contrast between them.
Friday, April 13 – With no early evening Moon to contend with, this is a fine opportunity to have a look at a group of galaxies between Leo’s paws. Start at Regulus and look due east toward Iota Leonis. Halfway between the two (less than a fist from Regulus) and two finger-widths northeast of Rho Leonis, you’ll encounter Messier Galaxies M95 (Right Ascension: 10 : 44.0 – Declination: +11 : 42) and M96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49) – both within the same low power field of view. At magnitude 9.2, the brighter – and slightly rounder – M96 lies northeast of 9.7 magnitude, M95. Pierre Mechain discovered both galaxies on March 20, 1781 and Messier added them to his catalog 4 days later. These two galaxies are two of the brightest members of the Leo I galaxy group located some 38 million light-years away.
To see another Messier member of the Leo I group, center on M96 and shift the galaxy south. From the north side of the low power field, the 9.3 magnitude galaxy M105 (Right Ascension: 10 : 47.8 – Declination: +12 : 35), nearby 10th magnitude NGC 3384 (Right Ascension: 10 : 48.3 – Declination: +12 : 38), and 12th magnitude NGC 3389 (Right Ascension: 10 : 48.5 – Declination: +12 : 32) will come into view. M105 was discovered by Mechain on the night Messier catalogued M95 and 96 but was not formally added to Messier’s catalog. Based on Mechain’s observing notes, Helen Sawyer Hogg added it to Messier’s list in 1947 – along with galaxy M106 and globular cluster M107. Mechain failed to notice M105’s bright neighboring galaxy – NGC 3384. NGC 3384 is actually slightly brighter than the faintest Messier discovered – M91.
We’re not done yet! If you center on M105 and shift due north less than a degree and a half you will encounter 10th magnitude NGC 3377 (Right Ascension: 10 : 47.7 – Declination: +13 : 59) – a small elongated galaxy with a stellar core. There are a dozen galaxies visible to moderate amateur instruments (through magnitude 12) in the Leo I region of the sky!
Saturday, April 14 – Today is the birthday of Christian Huygens. Born in 1629, the Dutch scientist went on to become one of the leaders in his field during the 17th century. Among his achievements were promoting the wave theory of light, patenting the pendulum clock, and improving the optics of telescopes by inventing a new type eyepiece and reducing false color through increasing the focal length of refractor telescopes. Huygens was the first to discover Saturn’s rings and largest satellite – Titan. Of the rings, Huygens said, “Saturn: encircled by a ring, thin and flat, nowhere touching, and inclined to the ecliptic.”
Wanna’ check Saturn out? It will be rising in the constellation of Virgo not long after the sky begins to turn dark. If you’re not sure of which “star” it is, just wait for awhile and you’ll find it about a fistwidth northwest of bright, blue/white Spica. Be sure to check out the ring system! Right now they have a very nice southern tilt which will allow you a great view of the shadow of the planet on the rings – and the shadow of the rings on the planet. If the atmosphere will allow, power up! Something you may never have thought of looking for could be happening… Can you see the planet’s edge through the Cassini division? Be sure to look for wide orbiting Titan and some of Saturn’s smaller moons slipping around the ring edges.
Tonight our challenge is also planetary – but it’s the planetary nebula – the “Ghost of Jupiter”. Begin by identifying the constellation of Hydra. Starting at Alpha Hydrae, head east about a fist’s width to find Lambda within a field of nearby fainter stars. Continue less than a fist southeast and locate Mu. You’ll find the “Ghost of Jupiter” (NGC 3242) lurking in the dark less than a finger-width due south. At magnitude 9, the NGC 3242 (Right Ascension: 10 : 24.8 – Declination: -18 : 38) gives a strikingly blue-green appearance in even small scopes – despite being more than 1500 light years away.
Sunday, April 15 – Tonight keep a watch for the “April Fireballs.” This unusual name has been given to what may be a branch of the complex Virginid stream which began earlier in the week. The absolute radiant of the stream is unclear, but most of its long tails will point back toward southeastern skies. These bright bolides can possibly arrive in a flurry – depending on how much Jupiter’s gravity has perturbed the meteoroid stream. Even if you only see one tonight, keep a watch in the days ahead. The time for “April Fireballs” lasts for two weeks. Just seeing one of these brilliant streaks will put a smile on your face!
And if you can’t take your eyes off Leo, then there’s good reason. The combination of Theta Leonis, Regulus and Mars certainly calls attention to itself!
While we’re out, let’s journey this evening towards another lovely multiple system as we explore Beta Monocerotis. Located about a fist width northwest of Sirius, Beta is one of the finest true triple systems for the small telescope. At low power, the 450 light year distant white primary will show the blue B and C stars to the southeast. If skies are stable, up the magnification to split the E/W oriented pair. All three stars are within a magnitude of each other and make Beta one of the finest sights for late winter skies.
If you hadn’t noticed, Saturn is at opposition tonight, meaning it will be viewable from dusk until dawn. Be sure to check out the “Ring King” – but wait until it has risen well above the lower atmosphere disturbance for a superior view!
Until next week, I wish you clear and steady skies!