Archive for November, 2007

Inflight Wireless — progress?

Monday, November 26th, 2007

Last week, while we were preparing for a Thanksgiving feast, we missed a couple important FCC announcements that may pave the way (finally) for inflight wireless broadband (or aeronautical mobile satellite services – AMSS).

On Tuesday the FCC granted ARINC’s request:

By this Order and Authorization, we modify ARINC Incorporated’s (“ARINC”) Aeronautical Mobile-Satellite Service (AMSS) authorization by granting ARINC’s request for authority for aeronautical earth stations (AES) to communicate with the Estrela do Sul satellite at the 63° W.L. orbital location, in various portions of the conventional Ku-band1 over the North Atlantic Oceanic Region (NAOR). Our action expands the availability of two-way broadband connectivity to passengers and crew for international flights and continues our efforts to enhance competition in an important sector of the mobile telecommunications market.

ARINC’s product is called SKYLink. It claims to be "the fastest in-flight broadband satellite service for business aircraft passengers" (which may be a bit dishonest considering Row 44’s technology – discussed later). It runs on a tail-mounted antenna and can provide speeds of up to 3.5 Mbps at up to 47,000 feet. SKYLink has coverage throughout the United States and on trans-atlantic flights to Europe (see: coverage map).

ViaSat Inc., another competitor in this rising market, also received good news:

With this order, we grant ViaSat, Inc. blanket authority for domestic operation of up to 1,000 technically identical transmit/receive earth stations aboard commercial aircraft. These earth stations will provide Aeronautical Mobile Satellite Service (“AMSS”), using the standard Ku-band frequency ranges 14.0-14.5 GHz (Earth-to-space) and 11.7-12.2 GHz (space-to-Earth), to link with leased transponders aboard the AMC-6 satellite operating at the 72º West Longitude orbital location. The ViaSat aircraft earth stations will provide two-way broadband communications for passengers and aircrew members aboard commercial airliners and private business jets, with access to email, the Internet, and corporate virtual networks. Implementation of the ViaSat AMSS system pursuant to this authorization will enhance competition in an important sector of the mobile telecommunications market in the United States.

ViaSat’s program, to be operated with its ArcLight technology, is very similar to Boeing’s plan to place 800 technically identical transmit and receive mobile earth stations. We were big fans of Boeings announcement when we discussed it last year, and were disappointed when it failed due to a lower-than-expected U.S. demand.

Finally, Aircell announced a partnership with E Technologies to implement the company’s network performance management system:

GenerationE is a premier IBM Tivoli partner with extensive experience in architecting service performance management solutions like the Tivoli Netcool solution. Aircell has developed inflight broadband services to allow passengers to use existing Wi-Fi enabled PDAs and laptops while airborne. American Airlines and Virgin America have both signed deals to deliver high-speed broadband connectivity on their domestic flights beginning in 2008.

Together with generationE, Aircell will supplement its current network monitoring and management capabilities on the company’s cutting-edge satellite and air-to-ground broadband cellular networks. Trending and demand forecasting of its cellular network will be further optimized with new capabilities provided by generationE, as well as enhancements to its data center monitoring.

"At Aircell, we measure success on both the reliability of our systems and cost of services," explained Mark Malosh, Vice President of Operations at Aircell. "We are confident that our partnership with generationE will help achieve both of these goals by helping us manage and monitor the performance of our expanding network environment."

The software, IBM Tivoli Netcool Performance Manager, will be used to manage Aircell’s terrestrial network of cell sites and its data centers, which provide fault tolerance and load-balancing capabilities to the Aircell network infrastructure. The software will report critical metrics such as latency measurements, and allow Aircell to conduct root cause analysis to quickly isolate, analyze and resolve network problems.

With these technology/provider announcements and some promising airline pledges, things are looking up for inflight broadband. As we discussed last month, Alaska Airlines will be launching an inflight wireless system within the six months using a system developed by Row 44 of California that uses a constellation of Hughes satellites. Unlike ground-based systems, this will provide seamless connectivity, even on flights to remote regions of Alaska and across the Pacific to Hawaii.

Alaska Airlines may even make the service free. That’s something SKYLink could probably not accommodate, as SKYLink offers a maximum download speed of 3.5 mbps, while Row 44 will provide about 45mbps. That’s enough capacity for a plane-full of passengers to connect to the free service.

FCC Moves Favor Inflight Broadband

Monday, November 26th, 2007

You may have missed it in your preparations for Thanksgiving, but last week the FCC made a couple of big moves that favor the deployment of AMSS (aeronautical mobile satellite services) —  better known as inflight broadband in the U.S.

First, the FCC granted ARINC’s request for Ku-Band aeronautical earth stations to communicate with Telstar 14/Estrela do Sul at 63 W.L., which will allow ARINC to deploy its SKYLink inflight broadband product:

SKYLink allows business aviation passengers to stay connected even at 47,000 feet. At speeds in excess of 3 megabits per second (Mbps), it’s about 6 times faster than a high-speed cable modem….

The SKYLink antenna is tail-mounted and fits on larger business aircraft including: Gulfstream GIV, GIV-SP, G400, GV, G500, G550, Cessna Citation X, and Bombardier Global Express/500/XRS and Challengers.

The SKYLink equipment is compact and lightweight. The tail-mounted dish antenna measures less than 12 inches in diameter. The satellite terminal, including antenna, weighs less than 40 pounds. ARINC Direct is currently working with original equipment manufacturers (OEMs) to make SKYLink a standard option on any new aircraft, but will also retrofit the necessary equipment to existing aircraft. 

Second, the FCC granted ViaSat, Inc. blanket authority for domestic operation of up to 1,000 technically identical transmit/receive earth stations aboard commercial aircraft, which will allow ViaSat to bring its ArcLight platform to market, which boasts:

*  More efficient use of bandwidth especially for completely random traffic patterns.
* Full use of bandwidth without loss of data throughput due to reservation schemes or contention-based protocols.
* Less power required through spread spectrum transmissions.
* Encoded signals with a combination of CDMA and PCMA technologies.

ArcLight incorporate two ViaSat-exclusive technologies: Code Reuse Multiple Access (CRMA) and Asymmetric Paired Carrier Multiple Access (A-PCMA). PCMA enables data transmissions coming back to the hub from remote sites to be combined within the same bandwidth as the outbound channel. Rather than requiring additional bandwidth for return channels, ArcLight needs only the space segment required by the outbound broadcast to support two-way satellite services.

We’ve been fans of in-flight broadband for years — especially Boeing’s excellent service. Unfortunately, Boeing decided to shut that service down, partly due to lower-than-expected demand in the U.S. market. For a time, we thought Panasonic Avionics was going to revive it, but that didn’t, er, pan out.

But as we reported this fall, Alaska Airlines seems poised to continue its history of industry-leading innovation (they were the first to move to online ticketing, way back in 1995) with its plans to launch inflight wireless Internet service next year based on Row 44’s satellite-based broadband connectivity solution. The price point for passengers? Latest reports indicate Alaska Airlines is leaning toward making the service free.

Now if the airlines would only bring back actual meals….

VW Space Up! Blue: A Very Cool Car

Wednesday, November 21st, 2007


Love this car. I’m buying it regardless of what it will look like off the production line. Shown at last week’s LA Auto Show. Gov. Schwarzenegger just had to sit in it, but he still won’t back down from their lawsuit served to the EPA and automakers:

“We understand the way the corporate world works, and we understand the way lawyers work. They will do everything they can to stop it, and we will do everything we can to move forward,” Schwarzenegger said during a tour of the Los Angeles Auto Show.

Beautifully designed, it features an interface that was probably designed by Apple. More than likely this was why VW’s CEO paid a visit to Steve Jobs back in September. The editors at Engadget think so:

Nice interior huh? And how ’bout that 7-inch touchscreen display slapped onto the center console. Pretty sweet right? You’re looking at the inside of VW’s third iteration of their Space Up! — the Space Up! blue — just revealed at the LA auto show. Now try this on. Reader Joona wonders if this is the result of recent collaborations between Apple and VW. After thinking about it some, we’re starting to wonder too. As Autoblog describes it, the concept touchscreen monitor "controls all conceivable functions" and is meant to demonstrate how future human-machine interfaces might look and operate. The touchscreen (no mention of multi-touch support) uses proximity sensors to react to gestures, apparently, without actually touching the display. The user can simply touch the "main menu carousel" to navigate to the desired category or manipulate the system with simple hand gestures near the display. Autoblog says, "Visually, this control is just as spectacular as it is intuitive." Now, chew on this for a second. VW announced earlier this week that all new VW models in 2008 2009 will have touchscreens. Is this what Apple has in store for us at January’s MacWorld?


Check it out — it’s coverflow, thanks to Edmund’s CarSpace:


Nice photo gallery on Autoblog:

Here’s a video clip showing details:


A Pan-African E-Network, With India’s Technology

Wednesday, November 21st, 2007


The theme of yesterday’s observance of Africa Industrialization Day was "Technology and Innovation for Industry – Investing in People is Investing in the Future."

Thus it’s more than a little fitting to note that InfoWorld yesterday reported that "a critical mass of countries are signing on to a plan for India to invest $1 billion in the Pan-African e-Network satellite project, a joint initiative with the Africa Union aimed at developing the region’s information and communication technology (ICT) infrastructure:"

The African Union last year entered into an agreement that calls for the Indian government to supply funds for the project. The Indian government will finance the project over a period of five years through a grant to the African Union. Ethiopia for example, has been given a grant of $2.13 million from India for the project.

So far, 27 African countries have signed agreements for the project, designed to connect African countries by satellite and fiber-optic network. The countries that have signed for the project include Zambia, Gambia, Ghana, Burkina Faso, Burundi, Mauritius and Tanzania.

The project will include installation of Very Small Aperture Technologies (VSATs) to carry VoIP (voice over Internet protocol) communication. The VSATs will be used for online education and telemedicine programs expected to extend ICT infrastructure to rural areas and other underserved communities. The telemedicine network will be used to share knowledge from Indian doctors with their African counterparts through an online training program.

"The project is significant to African countries because it overcomes limitations that make access to remote areas in most African countries difficulty by using VSATs," said Patrick Sinyinza, Zambia’s ambassador to Ethiopia, where the project is based.


More details of the project can be found here, while the official site is here.

It is hoped that creating the Pan-African e-Network will help ameliorate many of the challenges that individual countries have faced when trying to bring satcom to their citizens. (As an example, see this post which we wrote last year about Kenya’s problems bringing satellite connectivity to its residents.) (the India edition) provides insights into India’s eagerness to pursue relations with Africa, a move that is fueled by China’s increasing investment in oil extraction in the region:


Despite its plethora of problems, Africa is a land of promise and opportunity because of its vast natural resource wealth. It is this reason that India, China, the European Union and the United States have not been able to resist the temptation to form partnerships with African countries that are mutually rewarding. China in particular, has been signing deals after deals with African countries to tap the continent’s natural wealth and, in turn, aid Africa’s industrialisation and development. Of late, Asian trade and investment has been rising in Africa and this is part of the global trend towards South-South co-operation among developing nations….

With China`s influence growing over energy-rich Africa, India has already pressed the alarm button. New Delhi is following Beijing’s path to increase oil and gas imports from the resource-rich continent to reduce dependence on Middle East nations like Iran….

The prospects for partnerships with African countries have also grown in the recent past with a surge in investments by Indian companies in nations like Libya, Sudan, Nigeria, Egypt and Gabon. The co-operation holds significance as Africa has the potential to play an important role in enhancing India’s oil supply security through diversification of its crude oil import sources. Significantly, Africa has 10% of the world’s total oil and gas reserves and its hydrocarbon exploration potential remains relatively untapped.

To give a push to Indo-African ties, Prime Minister Manmohan Singh earlier this year visited Nigeria – Africa’s largest oil producing country. In Abuja, Singh announced a "strategic partnership" with Nigerian President Umaru Yar’Adua and signed four agreements to bolster bilateral relations, including in the energy sector. Singh’s historic visit to Nigeria was the first by an Indian Prime Minister in the last 45 years.

The investments by China and India into African infrastructure, beyond the oil industry, are in sharp contract to the limited investments by American and European companies. Few US companies have invested in the region except for the oil and mining sectors, and official US government figures show that American holdings in the sub-Saharan region total just USD 19.6 billion, according to Zeenews.

MidEast Sees Strong Growth in Satellite TV

Wednesday, November 21st, 2007

In the Middle East, the number of satellite TV channels has more than doubled over the past three years, according to a report in the Saudi newspaper al-Madina. provides a summary:

Currently 370 Arabic satellite TV networks broadcast to the Middle East; 56 belong to private companies, 54 are music channels and 38 are state owned. Since January 2004, the sector has grown some 270 per cent.

Media researcher ʿYsa Qasusi told al-Madina that about 22 per cent of Arabic satellite networks are based in the United Arab Emirates; 15 per cent are in the Kingdom of Saudi Arabia and 11 per cent are in Egypt.

Among the new networks pushing this incredible growth in satellite TV content: MTV Arabia, which just launched this weekend and features a blend of 60 percent international music and 40 percent Arabic music, with local adaptations of the channel’s popular non-music shows:

By emphasising local music talent and programmes aimed at addressing the concerns Arab youth have, MTV Arabia hopes to set itself apart from the other satellite music channels that saturate the Mideast market.

"We are not only a music channel, we are an entertainment channel where young Arabs will get a voice," programme director Patrick Samaha said. 

The launch of MTV Arabia comes at a time when Dubai is growing as a destination for the international jet set — a trend that MTV Arabia is likely to latch onto. In fact, they’re promoting a big party tonight at Dubai’s Boudoir, the "swanky, wannabe Parisian club [that] ranks as one of the most exclusive venues in the city." According to the MTV Arabia website:

Hip HopNa co-host DJ Fred Wreck. All the way from Hollywood, Wreck has worked with the best in the music bizz including Dr. Dre, Eminem, 50 Cent, Snoop Dogg and X-Zibit.

Hip HopNa co-host and Saudi Arabia’s first Hip Hop artist Qusai, AKA Don Legend

Plus the one and only DJ Dany Neville – Dubai’s Hip Hop Guru

The cameras will roll right through the star-studded night so bling yourself up and come prepared. Get there early to make sure you don’t miss the fun. Don’t say you weren’t warned!

If you’re camera-shy or just can’t make it to Dubai, MTV Arabia can be downlinked from Nilesat 101, located at 7° West (transponder 14; 11,997 MHz V, FEC 5/6, SR 27500) and Arabsat BADR 4 at 26° East (transponder 24, 12,169 MHz V, FEC 3/4, SR 27500).  With any luck you’ll catch a few videos of Lebanese superstar Haifa, who has taken the Middle East pop market by storm and is featured performing next to a 1965 Buick Wildcat in the video above.

Asian Space Race in High Gear

Tuesday, November 20th, 2007

Earlier this month, we wrote about China’s successful placement of a lunar probe into orbit around the moon, and raised the question of whether a new Asian space race could be said to be afoot.

The Los Angeles Times recently went to Asia to investigate that same question, and found that for China, India and Japan, their ambitions in space are fueled by a desire for recognition as global powers — not to mention entry into the growing commercial satellite market and the potential of lunar mining:

A closer look at Asia’s space balance sheet finds China the clear leader in manned space flight. Beijing also boasts the most extensive infrastructure, with three launch sites in place and a just-announced combined pad and theme park on the drawing board in southern Hainan island.

Also working in China’s favor, said Clay Moltz of the Naval Postgraduate School in Monterey, is solid government backing, its pick of the nation’s scientists and close, if far from transparent, links with the military…..

Japan is ahead of China in areas such as deep-space probes and robotics and enjoys a more focused, high-tech approach. But it suffers from relatively limited budgetary and popular support, and almost no help from the military….

Japan now has a relatively reliable launch system, but the program has had trouble attracting engineers given competition from other industries and a small pool of candidates because of the nation’s low birthrate.

India, meanwhile, has a strong grounding in earth sciences and engineering, an ambitious vision and programs that dovetail well with national development plans. But its program may not garner the budget needed to compete longer term with China, some analysts said.

"China’s resources are 10 times more than us," said Dipankar Banerjee, director of the Institute of Peace and Conflict Studies in New Delhi. "Compared to the Chinese, we still have a long way to go."

China and India see a robust space program as an essential step toward recognition as a global power.

"The space program is viewed as an essential prerequisite for India to be counted amongst the developed nations of the world," said Ranjit Singh Nagra, a military expert.

China’s recent great leap forward into space has generated a lot of heated debate among space fans, as this conversation thread over at Daily Tech exemplifies.

Absent from the LA Times summary, however, is South Korea — a nation that isn’t going to sit back and watch while its regional neighbors pursue the heavens: 

Korea plans to develop a powerful two-stage rocket that can send a satellite to the moon by 2017, the government said Tuesday (Nov. 20).

The road map calls for the building and testing of the 300-ton Korea Space Launch Vehicle-1 (KSLV-II) booster rocket so the country can launch its first lunar exploration satellite in 2020, the Ministry of Science and Technology said.

If the plan is successfully carried out, Seoul will launch a lunar probe in 2025, it said…..

It also said efforts will be made to attain technological independence in key rocket systems by 2016 and in commercial satellite production starting in 2020.

Seoul plans to launch a large satellite weighing about 100 kilograms every 3-4 years, and at least two smaller satellites every year.

Even in this new Asian space race, however, there’s no need to fully reinvent the rocket ship. As with India’s lunar ambitions, South Korea has been relying on Russian technology and assistance to develop the Korea Space Launch Vehicle, the two-stage rocket for satellite launches set to debut next year. The 11 satellites South Korea has launched since 1992 for space and ocean observation and communication have all been carried aboard foreign-made rockets launched from other countries.

Rural Missouri — we want high speed

Monday, November 19th, 2007


Missouri Governor Roy Blunt is trying to get to the bottom of why his rural communities face few, if any, broadband options. He appointed a 25 individuals to the Rural High-Speed Internet Access Task Force. From a Springfield, MO editorial:

There’s no doubt that in many parts of rural Missouri, and southwest Missouri is no exception, broadband services are hard to find. You don’t have to drive far outside the city limits of Springfield to find communities that don’t have access to broadband cable services and inexpensive high-speed Internet. Indeed, in today’s high-tech world, having access to high-speed Internet is necessary for good business, and as such, bringing more of it to rural Missouri would be good for the state’s economy and good for those consumers who don’t have it now.

Blunt directed the task force to: (link)

  • Assess the current level of high-speed Internet access available in Missouri
  • Identify barriers to deployment to underserved areas including economic, geographic, regulatory, and market barriers
  • Identify potential options to increase the deployment of high-speed Internet access in underserved communities
  • Review best practices in other states to increase high-speed Internet access
  • Recommend statutory, regulatory, and policy changes needed to increase the availability of high-speed Internet services across the state.

But until T1’s blanket rural Missouri, people are finding ways to stay connected:

In many southwest Missouri counties, cattle ranchers buy and sell livestock online using high-speed service through satellite dishes.

SIRIUS 4 Launch

Monday, November 19th, 2007

Intended to deliver broadcast and broadband services across Europe and Africa, the SIRIUS 4 satellite successfully launched yesterday for SES-Sweden:

A Proton launch vehicle successfully lifted the SIRIUS 4 satellite into orbit today, marking the fourth mission of the year for International Launch Services (ILS).

The Proton Breeze M vehicle, built by ILS partner Khrunichev Space Center of Moscow, lifted off from Pad 39 at the cosmodrome at 4:39 a.m. today local time (5:39 p.m. EST Saturday, 22:39 GMT Saturday). After a 9-hour-13-minute mission, the launcher released the satellite into geostationary transfer orbit.

The SIRIUS 4 satellite is expected to go into service at the beginning of January at 5 degrees East longitude, where it will deliver broadcast and broadband services across Europe and parts of Africa for SES SIRIUS of Sweden.

“This was an especially important mission for ILS and our customer, SES SIRIUS,” said ILS President Frank McKenna. “ILS and our partner, Khrunichev, continue to focus on performance and on our long-term relationship with the SES group of companies.” This was SES SIRIUS’ first mission with ILS, which has launched 12 other satellites on Proton for sister companies SES ASTRA and SES AMERICOM since 1996.

“We are very proud and satisfied that the SIRIUS 4 mission has been a success,” said Hakan Sjodin, managing director of SES SIRIUS. “SIRIUS 4 will benefit our customers and extend our coverage and service in Eastern Europe. The success of the SIRIUS 4 mission is a milestone in our company history and we would like to express our appreciation of the good cooperation with our launch partners, International Launch Services and Lockheed Martin Commercial Space Systems.”

Lockheed Martin built the SIRIUS 4 spacecraft using its A2100 platform. This was the 10th Proton mission with this type of spacecraft.

The launch video:

The Sirius satellites will be operated by the Swedish Space Corporatoin. Sven Krohn, who from his bio appears to be the Swedish space business superstar, runs their blog.

DIY Friday: Fighting Global Warming

Friday, November 16th, 2007

As we wrote the post below about the Vanco Arctic Expedition, we started to think, what can we do to fight global warming?

Sure, we’ve bought our compact flourescent bulbs and weather stripped our house and turned down the thermostat and at least thought about buying a Prius. But there’s gotta be more that a DIY-inclined person can do, right?

And then Rocco commented, apropos of nothing (as is often the case), that he knew lots of Canadians who had grown up with backyard ice rinks. And we thought, that’s it! If the polar ice caps keep melting, can’t we just create back yard ice caps to reflect the sun’s heat back into space — and get a little puck time in in the process?

Turns out, building your own backyard ice rink is easy from a DIY perspective:

 I built my rink using a garden-variety lightweight tarp as a watertight liner. This method is more expensive than just hosing down a patch of flattened snow and hoping for cooperative temperatures, but it’s also almost foolproof. The rink structure can be built before the really cold weather sets in, and because the water stays put, the rink will withstand a bout of warmish weather without leaking away. Plus, the rink components are reusable, making the amortized cost more agreeable….

 Once your future greats have put their skates to the ice for couple of hours, you’ll want to resurface it. This is best done at night when the temperatures dip. The easiest way to resurface the ice is to spread a thin layer of hot water over the surface. The hot water melts the ice shavings and fills in the blade gouges, and then quickly melds with the existing ice to create a nice flat surface. You could just use a hose to accomplish the resurfacing flood, but a simpler and faster way is to build a Zambini. (My kids started calling it that, and the name stuck.) The Zambini is a T-shaped hose extension made from off-the-shelf underground sprinkler fittings. Just screw all the fittings together and drill a series of holes on the underside of the horizontal part of the contraption.

Attached to your hose, the Zambini is used like a broom. The beauty of the device is that—like its inspiration, the Zamboni—it gets the hot water right down to the ice level without losing too much water to evaporation, and the little holes spread the water out evenly.

Of course, back yard ice rinks only work in the winter. But DIYers can keep cool in the summer by making DIY ice cream in a bag or by building this DIY air conditioner using a simple fan and some ice.

Then again, maybe we should just go turn down the thermostat a few more degrees. 

Ice Ice Baby

Friday, November 16th, 2007

With a stunning website more befitting a reality television show than a scientific expedition, the Vanco Arctic Survey is relying heavily on multimedia web technology to share its expedition with the public:

The Vanco Arctic Survey is a pioneering international scientific endeavour, likely to prove the most ambitious ever undertaken on the North Pole ice cap. The North Pole ice cap, which floats on the Arctic Ocean, is one of our planet’s defining features and is in peril, melting at an accelerating rate. The survey will capture, for the first time, detailed information about the thickness of the ice and snow and help to determine just how long the ice cap will exist in a climate-changing world.

The multimedia gallery can be found here. We particularly like this video (hosted on YouTube) of arctic wolves checking out the team as they drill for ice core samples, transmitted directly from the arctic:

So how does the team deliver their video, audio and images to a global audience? They use the Iridium low-earth orbit satellites for communications and video feeds. has the details:

Satellite coverage of both polar regions is limited to one service – the Iridium satellite network – and these low-orbit sats are designed for speech and low data rate communications, with a maximum data rate of only 2,400 bits per second.

To handle large quantities of data, the expedition will also be using six satellite modems in parallel to allow real-time webcam footage, which is compressed and combined with low frame rates.

The team will be using ‘sledges’ – large floatation devices containing the equipment – to transport the systems across the ice cap.

The onboard sledge computer uses a Linux-based system and consumes only two watts of electricity. Its main functions are to archive data, read data cards from the cameras and bio-data sources, handle compressed webcam images in real-time and feed data files to the six Iridium modems.

The expedition team will carry out tests to see how efficiently the system can transmit data back to the project’s headquarters at Watlington, near Oxford, UK.

The aim is to send back same-day footage which will enable the team’s progress to be followed.

Pen Hadow, who is leading the expedition, recently spoke at the launch of the first World Responsible Tourism Day, saying the day is of "colossal significance" to preserving the polar ice caps. 

To get a better idea of how limited satcom coverage is at the poles — and why — check out this cool flash visualization of orbiting satellites