A Step Toward Quantum Communications with Space

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Sending quantum information in the form of qubits (quantum bits) have been successfully carried out for years. Firing indecipherable packets of quantum data (or quantum states) via photons can however degrade the message as the photons travel through the dense atmosphere. Also, the distance of transmitting data is severely hindered by other factors such as the curvature of the Earth. Now, for the first time, Italian scientists have carried out a successful mock single-photon exchange between Earth and a satellite orbiting at an altitude of 1485 km. Although transmission may be restricted here on Earth, the use of satellites will greatly increase the range of such a system, possibly beginning an era of long-distance quantum communication with space.

The key advantage to quantum communications is that it is perfectly secure from being hacked. In a world of security-conscious information transmission, the possibility of sending information hidden in the quantum states of photons would be highly desirable. A major drawback of sending encoded photos here on Earth is the degradation of data as the photons are scattered by atmospheric particles. The current record stands at 144 km for an encoded photon to travel along its line of sight without losing its quantum code. That distance can be increased by firing encoded photons along optical fibres.

But what if you used satellites as nodes to communicate the encoded photons through space? By shooting the photons straight up, they need only travel through 8 km of dense atmosphere. This is exactly what Paolo Villoresi and his team at the Department of Information Engineering, University of Padova with collaborators in other institutes in Italy and Austria hoped to achieve. In fact, they have already tested the “single-photon exchange” between a ground station and the Japanese Experimental Geodetic Satellite Ajisai with some good results.

Weak laser pulses, emitted by the ground-based station, are directed towards a satellite equipped with cube-corner retroreflectors. These reflect a small portion of the pulse, with an average of less-than-one photon per pulse directed to our receiver, as required for the faint-pulse quantum communication.” – From “Experimental verification of the feasibility of a quantum channel between Space and Earth“, Villoresi et al..

The communication between satellite and observatory
They achieved this feat by using existing Earth-based laser ranging technology (at the Matera Laser Ranging Observatory, Italy) to direct a weak source of photons at the Ajisai, spherical mirrored satellite (pictured top). As the powerful laser ranging beam pinpointed the satellite, it was switched off to allow the weaker encoded laser to fire pulses of data. The two lasers could easily be switched to be sure the Ajisai was receiving the photons. Only a tiny fraction of the pulses were received back at the observatory, and, statistically speaking, the requirement of less than one photon return per laser pulse for quantum communications was achieved.

This is the first step of many toward quantum communications, and it by no means demonstrates the quantum entanglement between two photons (this situation is described in great detail by one of the collaborators in a separate publication) – now that would be the ultimate form of quantum data transmission!

Source: arXiv, arXiv blog

Happy Birthday Vanguard 1, and Welcome Home?

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Jim Oberg has written a very interesting article at MSNBC.com, commemorating the 50th anniversary of the launch of mankind’s fourth artificial satellite, Vanguard 1. While it is no longer functioning or communicating, it is the oldest satellite still in orbit. Jim says, “Vanguard 1 was the first artificial earth satellite powered by solar cells, and its small suite of instruments provided unprecedented information on Earth’s size and shape, air density and temperature ranges, and the micrometeorite density in space. Tracking its orbit helped geophysicists realize that Earth is not round but slightly pear-shaped, with a slight, symmetric equatorial bulge.”

Jim has a lot of good history included in the article, but most intriguing, Jim reports Vanguard 1 could become the first satellite brought home, for museum display, by a new generation of robotic space vehicles. That would be incredible! Such an attempt would be a demonstration of robotic space vehicles’ capabilty, in addition to providing an Earth orbit (and highly exciting) version of retrieving Gus Grissom’s Liberty Bell 7 from the ocean floor. Do check out Jim’s article.

Jim Oberg, of course, is a noted journalist, author, linguist (sorry, inside joke) and space consultant for NBC News.

Satellite Fails to Reach Proper Orbit

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Just a quick piece of sad news. SES Americom reported that its AMC-14 satellite failed to reach its orbit on Saturday after it was launched by a Russian Proton Breeze-M rocket. Despite the failure, though, there might be hope that the satellite will be broadcasting HD television eventually.

The company said that the problem happened during the second burn of the fourth stage, and resulted in the satellite – built by Lockheed Martin – not reaching its geostationary transfer orbit.

With this failure, the company has suspended plans to ship the next satellite to the launch site, and its April launch will be postponed until a thorough investigation can be done. Dish Network was originally planning to lease the entire capacity of the satellite to increase the number of high-definition television channels that it broadcasts. They were planning to launch three new satellites in 2008.

It’s not a hopeless situation, however. SES Americom president Edward Horowitz said he’s working with Lockheed Martin engineers to figure out a way to get AMC-14 back into its correct orbit. The downside is that the fuel used to get the satellite into its proper orbit will shorten its broadcast lifetime, since it’ll have less fuel for station keeping.

Original Source: SES Americom News Release

Tracking Debris from US Spy Satellite USA 193; Delays to Rocket Launch

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The shoot down of US spy satellite USA 193 was condemned by some quarters of the international community. However, the fact remains, this was a resounding success for the US military. Observers of the operation to destroy the potentially dangerous satellite likened it to “trying to fire a missile through the eye of a needle”. After all, the dead satellite was orbiting at a height of about 250 km, and the satellite-killing missile was fired from a boat; assuring impact with an object the size of a small bus was never going to be easy. But the mission was a success and the satellite disintegrated into bits (no bigger than a football). Now the task of tracking the debris is under way, and the fallout from last months fireworks are impacting the scheduled launch of other space missions…

According to CelesTrak, there are 52 catalogued bits of USA 193 orbiting the Earth. The pieces range in altitude from 167 km (at the closest approach) to over 2,600 km (at apogee – the highest point of orbit) and they are being tracked with great accuracy (pictured above).
Plot showing the projected lifetime of the USA 193 space debris (credit: CelesTrak)
The 5,000 pound (2,300 kg) satellite apparently disintegrated into many small pieces of debris, each no bigger than the volume of a football (equivalent to a circle with a diameter of 20 cm). Anything smaller than 10 cm cannot be tracked with any degree of accuracy, so an analysis by CelesTrak (pictured left) shows the upper and lower bounds of debris that can be tracked and how long they are likely to stay in orbit.

As a rule, larger pieces of debris will remain in orbit for longer, whilst the smaller objects will have less momentum to stay above the Earths atmosphere. As can be seen, most of the debris can be expected to burn up through atmospheric re-entry within 30 days, but there is a massive difference in the lifetime of the remaining 10 cm debris when compared with the 20 cm debris. The remaining 5% of large chunks of satellite are projected to stay in orbit for 50 days longer than their smaller cousins.

Tracking these bits of debris is an arduous task, but the monitoring continues. The destruction of USA 193 has influenced the scheduled launch of rockets since February 20th, and disruption is likely to continue should these larger pieces of debris pass through spacecraft launch windows. The launch of a US National Reconnaissance Office NROL-28 reconnaissance satellite last Friday from Vandenberg Air Force Base in California, has been postponed for two weeks until the USA 193 debris poses no threat of collision.

Universe Today coverage of the demise of satellite USA 193:

Original Source: CelesTrak

UK Urged to Focus on Satellite Technology, not Manned Exploration of Space

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The UK is the only G8 country (the eight richest countries in the world) without a manned space program. 20 years ago, Prime Minister Margaret Thatcher put pay to any hope for a British astronaut by opting out of plans citing it as “too expensive” for the island nation. However, the UK government signalled last month they were considering a review of this space exploration policy, receiving a mixed reaction. A prominent satellite manufacturer has come forward with a suggestion that the UK may after all be better suited to constructing a space exploration “infrastructure” and leaving manned exploration to the ESA and NASA…


In 1986, the UK was effectively ruled out of manned expeditions into space. Plans outlined by the European Space Agency (ESA) at the time were considered too expensive for the nation to pursue, so the UK concentrated on its civil and defence space capabilities through robotic explorers rather than participating in any national or international collaboration.

As of 2007, after two decades of research and development, Britain spends over £200 million ($400 million) a year on space initiatives, putting some of the world’s most advanced technology into space. UK companies such as SSTL, Qinetiq, Logica and Astrium are leading the world in certain space technology areas as a result. Many in the industry (especially the satellite manufacturing sector) would agree that the lack on participation in a manned space program has provided growth in robotic exploration sectors.

This may be the case, but there is pressure for the UK to catch up with the other seven nations of the G8 and begin sending British astronauts into space rather than depending on NASA and the ESA. British-born astronauts have been into space, such as Piers Sellers (pictured above), Michael Foale (dual nationality – Britain and USA) and Nicholas Patrick; Helen Sharman was the first Briton in space in 1991. All British astronauts were either naturalized American or involved with other space programs, little investment was made by the UK government in any manned mission.
An artists impression of the Habitation Extension Module - a concept by British designers for the ISS (credit: SimComm/Ducros)
Many academics would disagree with the UK’s past unwillingness to “get involved” in a manned program. As the worlds nations become more and more space-worthy, many believe the UK is being left behind and the dependence on NASA and ESA will become problematic as time goes on. There would be economic and educational value in starting a UK manned space program too. Looking back on the stimulation that the Apollo program had on the US in the 1960’s, the nation saw a surge of interest in the sciences and engineering subjects. This educated an entire generation of college and university students who have formed the foundations of the hugely influential space program that exists today.

The UK needs to take early steps for a future role in a human exploration programme. It can stimulate education and excite the young to get involved in science and technology.” – Professor Frank Close, Oxford University and Chairman of the UK Space Exploration Working Group (in an interview with The Independent Online).

But the idea of a UK manned space program may push the nation beyond its means according to David Williams, head of Avanti, a satellite communications company. Williams believes that the UK, after many years of space innovation and robotic exploration of space and the planets, is ideally placed to dominate the world’s communication ability with deep space missions.

If mankind is going to exploit the resources of the solar system, you are going to have to travel over very long distances and you are going to have to communicate over very long distances and you will need a network of data-relay satellites. The UK has a big advantage. We have the opportunity to control the space internet, which is going to be this network of data-relay satellites.” – David Williams.

Following this logic, as space exploration is an international effort, letting big space agencies such as ones controlled by the USA, Russia and Europe pursue manned exploration, the UK has an important role to play to insure advanced communication technology keep the international manned space efforts in touch with Earth.

Either way, this is an exciting time for UK space efforts. Although recently buffeted by funding shortages, there appears to be some positive movement toward greater involvement in international collaboration and investment in satellite technologies.

Source: The Guardian Online, The Independent Online

Nanotechnology and “Electrochromics” Successfully Tested On Board Satellite MidSTAR-1

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The zero-gravity of Earth orbit is a massive attraction to developers of new technologies. This highly controlled environment removes one of the key forces acting on experiments here on Earth, therefore allowing new techniques to be tried out. Although it can be great to get a highly sensitive experiment to test new technologies into orbit, the experiments must also be robust enough to cope with the massive forces and vibrations during a rocket launch into space.

The US Naval Academy has announced that two new technologies have succeeded in orbital experiments on board the MidSTAR-1 satellite, signifying these new high-tech methods can indeed be carried out in space, and as an added bonus, they may have revolutionary applications down here on Earth…

The US Naval Academy (USNA) satellite called MidSTAR-1 was launched from Florida’s Cape Canaveral Air Force Station on March 8th, 2007 as a part of the USNA’s Small Satellite Program (SSP). The SSP is intended to send miniature, inexpensive satellites into orbit where experiments and other operations can be carried out. The satellites and experiments are designed, constructed and controlled by officers in the US Navy.

Results from two experiments being carried out on MidSTAR-1 have just been announced, and they appear to be a resounding success. The first experiment uses nanotechnology  to detect dangerous chemical compounds in the air. Almost like a miniature smoke detector, the new method is designed for use in space environments (on board missions such as the International Space Station) as well as counter-terrorism activities here on Earth. The second experiment tests the response of a radiative film (no thicker than a plastic freezer bag) that could be used to regulate the temperature of spacecraft. Both technologies have never been tested in space and both appear to have functioned rather well.

In the nanotechnology experiment, the Nano Chemsensor Unit (NCSU) uses very thin nano-tube material (10,000 times thinner than a human hair) to detect poisonous gases in a space-borne environment, primarily protecting astronauts. In fact, this new detector is only the size of a pencil eraser, but has many times the sensitivity of a household smoke detector. The NCSU performed excellently, detecting the target contaminants repeatedly. It is hoped that tiny detectors such as this will be installed in future NASA missions to detect fuel leaks or contamination by common air pollutants such as nitrogen dioxide. Exposure to the vacuum of space, radiation and vibrations at launch do not seem to significantly affect the prototype sensor. Terrestrial applications of the system include atmospheric monitoring and even explosive residue detection during homeland security exercises.

The second technology to be successfully tested is a thin film that changes its characteristics depending on the amount of electric current that is passed across it. This revolutionary material could be used to “wrap” spaceships so their temperature can be regulated. The film can radiate waste heat away from the body of the spacecraft, or can insulate it, holding the heat inside. The science behind this material is known as electrochromics, and before this mission it had never been tested in space. The material is very lightweight, efficient and uses very little energy, a superb addition to any spaceflight mission. Terrestrial applications of this material include using an electrochromic film to coat buildings, making them energy efficient during the winter, but keeping homes cool during summer. This should reduce the amount of energy required to heat and cool buildings, cutting down on cost and the production of greenhouse gases.

Another exciting use of this film could be to use it to surround future robots exploring the solar system, optimizing the temperature for best performance. Also, this technology would be vital to the energy conservation on future manned Moon and Mars bases.

Whatever the application, these preliminary experiments are proving to be highly successful and may revolutionize some aspects of space- and terrestrial-based technology.

MidSTAR is the seventh piece of hardware that the small satellite program has flown. It’s by far the most sophisticated and most ambitious. It’s proven to be the most productive and all four experiments operating in space are producing excellent data.” – Billy Smith, Director of the Small Satellite Program.

Source: Science Daily

Space Debris May be Catastrophic to Future Missions (and Google Earth is Watching…)

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Kessler Syndrome could be a frightening situation for space travel. No, it’s not a health risk to the human body in zero-G and it’s not a psychological disorder for astronauts spending too much time from home. Kessler Syndrome is the point at which space travel becomes impossible without hitting into a piece of space junk, jeopardizing missions and risking lives. In extreme predictions, space debris from our constant littering of low Earth orbit, collisions between bits of rubbish may become more and more frequent, causing a catastrophic cascade of debris multiplying exponentially, falling through the atmosphere and making space impassable.

In the meanwhile, space mission controllers must be acutely aware that there could be an odd bolt or piece of old satellite flying toward their spaceship at velocities faster than the fastest rifle shot. Spare a thought for the space debris trackers as they try to keep a record of the 9,000+ pieces of junk currently orbiting our planet… but wait a minute, Google Earth can give us a ringside seat!

Strict international civil aviation-style laws may need to be imposed on the worlds space agencies if future generations of the human race are going to make it in space. This stark warning comes from Tommaso Sgobba, Director of the International Association for the Advancement of Space Safety, who will be presenting his case to the United Nations in April. Sgobba’s main argument comes from the danger associated with the escalating accumulation of space debris in Earth orbit, should these high speed bits of junk hit a spaceship, satellite or an astronaut, death and disaster may ensue. It may get worse than this, possibly paralysing the Earth from having access to space at all.

Failure to act now to regulate space to protect property and human life would be pure folly.” – Tommaso Sgobba.

Other scientists agree with Sgobba, recommending that future missions in to space abide by some strict codes of practice (possibly more strict than those imposed on international civil aviation) to drastically cut the rate of orbital littering by the 20 countries currently able to send stuff into space.

Even the most tightly controlled missions, such as the International Space Station, are expected to shed bits and pieces over the course of their lifetimes. Space junk comes in all shapes and sizes and can be anything from a small screw to entire dead satellites. Recorded examples of space junk include an old glove lost by Ed White during the first ever US space walk in 1965 (during the Gemini-4 mission), a camera that Michael Collins let slip in space in 1966 (during the Gemini-8 mission) and a pair of pliers that International Space Station astronaut Scott Parazynski dropped during an EVA last year.

Some space debris near misses include:

  • Space Shuttle dodge: Space Shuttle Atlantis had to avoid collision with a piece of a Russian satellite by carrying out a seven second burn of its engines in 1991.
  • Aircraft scare: Bits of an Russian ex-spy satellite fell through the atmosphere coming very close to a Latin American Airbus, carrying 270 passengers in 2006.
  • Personal injury: fortunately there is only one documented account of someone being hit by a piece of debris on the ground. In 1997 a woman from Oklahoma was hit on the shoulder by a piece of a fuel tank from a Delta II rocket. She was unhurt and lived to tell the tail.

It is hoped that tighter controls on the rockets, satellites and spacecraft will slow the rate of junk increase, but the problem is already pretty worrying for long-term missions in orbit around the Earth. The two critical regions filling with debris are in low Earth and geosynchronous orbits, a few hundred and 22,300 miles high respectively. Low Earth orbit will cause problems for spacecraft to actually leave the atmosphere and geosynchronous orbit may hinder future communication satellite insertions.

To safeguard our access into space, and avoid an increase in debris-related incidents, action will need to be taken.

Google Earth-watch
Two screenshots. Looking up toward the constellation of Leo. One screen with and one without the positions of space debris.
During the research on this article, I came across some work being funded by Ministry of Culture of the Republic of Slovenia, Municipality of Ljubljana, where researchers are making debris location data available to the public via a plugin for the Google Earth application. According to the groups blog, the data is taken from a U.S. government-owned space observatory so known space debris (or as the blog calls it “pollution”, which it really is) can be tracked.

On experimenting with the new space debris folder, it really did strike home as to what a problem space junk is becoming. For starters, there is an impossibly thick near-Earth layer and a distinct ring representing the geosynchronous debris. Plus, each item can be selected and information on the individual bits of debris can be found out… see the screenshots to find out what I mean…
3D view of junk in low Earth orbit.

Get the space junk plugin for Google Earth (read Google Earth documentation to learn how to use this plugin).

News Source: Guardian.co.uk

US Cruiser Strikes Dead Spy Satellite

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Officials have confirmed that the US spy satellite, USA 193, has been hit by an anti-satellite missile fired from USS Lake Erie positioned west of the Hawaiian Islands in the mid-Pacific at 10.30pm (US Eastern Time) Wednesday night. Fears of the propellant hydrazine being released into the atmosphere prompted the military response. Although plans for the missile strike were hampered by bad weather, the launch appears to have gone ahead regardless.

The 10.30pm time window was chosen by the US so that should the first attempt fail, a second and then a third attempt could be carried out. The window was only 10 seconds long, and BBC correspondent Jonathan Beale, based in Washington, says this operation was hugely ambitious and likened it to “trying to fire a missile through the eye of a needle.”
The anatomy of a satellite shoot down (credit: BBC)
It is hoped that the modified Standard Missile-3 (SM-3) successfully destroyed the large orbiting mass, containing 450kg (1,000lbs) of the poisonous propellant hydrazine. The SM-3 does not carry a warhead; it depends on its high velocity and weight to destroy the target. Travelling at a velocity of over 17,000 mph, on impact the missile and satellite should break up, creating debris and hopefully destroying the full fuel tank. Most of the debris is expected to burn up in the Earths atmosphere over the next 15 hours (or two Earth orbits), and all of it is expected to have re-entered over the next 40 days, eliminating the risk of the poisonous fuel falling to Earth. However, at least 24 hours will be needed to assess how successful the strike has been.
The US spy satellite, that malfunctioned soon after launch, has been destroyed
In an official statement, the Department of Defence has said, “A network of land-, air-, sea- and space-based sensors confirms that the U.S. military intercepted a non-functioning National Reconnaissance Office satellite which was in its final orbits before entering the Earth’s atmosphere […] At approximately 10:26 p.m. EST today, a U.S. Navy AEGIS warship, the USS Lake Erie, fired a single modified tactical Standard Missile-3, hitting the satellite approximately 247 kilometers (133 nautical miles) over the Pacific Ocean as it traveled in space at more than 17,000 mph.

The missile strike has prompted anger from both Russia and China, as the nations see it as a provocative manoeuvre by the US, but US officials insist that the missile strike was not intended to showcase their anti-satellite technology and was not used to destroy any top-secret orbital weapon.

Sources: CNN, BBC

US Planning to Shoot Down Dead Spy Satellite

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The US Navy is planning to shoot down a dead spy satellite that broke down shortly after it was launched in December 2006. Not only are there fears that the large satellite could survive re-entry through the Earth’s atmosphere causing damage and perhaps fatalities, the satellite is also carrying the poisonous hydrazine propellant that could be a health risk if inhaled. Therefore plans are afoot to destroy the craft in orbit rather than letting it fall to Earth some time late February or early March.

This has been a frustrating time for the US military. As previously reported on the Universe Today, one of their most advanced spy satellite systems broke down soon after it was launched into space, leaving mission controllers in the dark as to where the satellite was going. This is bad enough, but if the satellite fell to Earth, it could reveal potentially sensitive secrets about the US spying technology. And not forgetting the potential risk of damage or death should the chunk of high-tech scrap fall to Earth… the US military is now planning to take action rather than leaving it up to gravity to decide where the satellite will crash.

Officially, the reason for the planned shooting down of the craft is not to destroy top secret technology (as most of the sensitive material is likely to burn up) but to prevent deadly fumes from being produced from the propellants the craft has in abundance onboard (after all, it didn’t have much of a chance to use any of its fuel). This is an opportunity for the US Navy to use one of its ballistic missile launchers onboard one of its support vessels. The Arleigh Burke class destroyer, USS Decatur (pictured) underwent ballistic missile launch tests last year, built to intercept incoming missiles high in the atmosphere. The satellite, presumed to be in a low Earth orbit, may be reached by such a missile defence system.

The area affected by the hydrazine should the fuel tanks survive re-entry would cover two football pitches, and if inhaled, would have similar effects to chlorine or ammonia – causing a burning sensation in the lungs. If too much is breathed in, it could prove deadly. A US military general stated that should the plan go ahead, they will take one missile shot and then assess whether a second would be required during a two day window. He also added that the Space Shuttle Atlantis will have landed before any such interception attempt is made.

US Spy Satellite Could Crash To Earth In February

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After all the excitement surrounding the possibility of asteroid 2007 WD5 hitting Mars and the concern of Near Earth Asteroid 2007 TU24 dropping to Earth, we now have something new (and manmade) to worry about. A US spy satellite has lost power and its orbit has begun to degrade. Officials are sketchy about the details, but the large satellite could survive the burn of re-entry and crash into the surface… but we don’t know where. The satellite might contain dangerous materials… but we can’t be sure. Either way, the dead spy satellite is expected to drop to Earth late February or early March.

This event could prove embarrassing for the US government, as there is little idea where the site of impact will be, sensitive US secrets could be exposed about the technology behind the orbital capabilities of the superpower nation. Officials have declined to comment whether the satellite could be shot down by missile, but this will surely remain an option.

Numerous satellites over the years have come out of orbit and fallen harmlessly. We are looking at potential options to mitigate any possible damage this satellite may cause.” – Spokesman for the National Security Council, Gordon Johndroe

The problem doesn’t stop with the possibility of fatal damage should the satellite fall in the wrong place. An anonymous official has added there may be the possibility the satellite could be carrying hazardous materials. During atmospheric burn-up, this unknown material could be spread over thousands of miles of atmosphere.

This usually isn’t a concern when satellites and other debris are brought to Earth in controlled re-entries. Large defunct satellites can usually have their orbital trajectories finely tuned so they fall safely though the atmosphere and crash into “satellite graveyards” in deep ocean trenches (i.e. the Mir space station was guided out of orbit in 2001 and sunk in the Pacific 6000 km off the Australian coast).

Hopefully a solution to this tricky problem can be found quickly, but it is hoped that most of the satellite will disintegrate during re-entry and any leftovers drop into the ocean… but it would be nice to know if there is a risk of impact anywhere other than the oceans. 

Source: MSNBC.com