Galileo Satellite Recovered And Transmitting Navigation Signals
Europe’s fifth Galileo satellite, one of two delivered into a wrong orbit by VS09 Soyuz-Fregat launcher in August, has transmitted its first navigation signal in space on Saturday 29 November 2014. It has reached its new target orbit and its navigation payload has been successfully switched on.
A detailed test campaign is under way now the satellite has reached a more suitable orbit for navigation purposes.
Recovery
The fifth and sixth Galileo satellites, launched together on 22 August, ended up in an elongated orbit traveling up to 25 900 km above Earth and back down to 13 713 km.
A total of 11 maneuvers were performed across 17 days, gradually nudging the fifth satellite upwards at the lowest point of its orbit.
As a result, it has risen more than 3500 km and its elliptical orbit has become more circular.
“The maneuvers were all normal, with excellent performance both in terms of thrust and direction,” explained Daniel Navarro-Reyes, ESA Galileo mission analyst.
“The final orbit is as we targeted and is a tribute to the great professionalism of all the teams involved.”
The commands were issued from the Galileo Control Centre by Space Opal, the Galileo operator, at Oberpfaffenhofen in Germany, guided by calculations from a combined flight dynamics team of ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany and France’s CNES space agency.
The commands were uploaded to the satellite via an extended network of ground stations, made up of Galileo stations and additional sites coordinated by France’s CNES space agency.
Satellite manufacturer OHB also provided expertise throughout the recovery, helping to adapt the flight procedures.
Until the maneuvers started, the combined ESA–CNES team maintained the satellites pointing at the Sun using their gyroscopes and solar sensors. This kept the satellites steady in space but their navigation payloads could not be used reliably.
In the new orbit, the satellite’s radiation exposure has also been greatly reduced, ensuring reliable performance for the long term.
A suitable orbit
The revised, more circular orbit means the fifth satellite’s Earth sensor can be used continuously, keeping its main antenna oriented towards Earth and allowing its navigation payload to be switched on.
Significantly, the orbit means that it will now overfly the same location on the ground every 20 days. This compares to a normal Galileo repeat pattern of every 10 days, effectively synchronizing its ground track with the rest of the Galileo constellation.
The navigation test campaign
The satellite’s navigation payload was activated on 29 November, to begin the full ‘In-Orbit Test’ campaign. This is being performed from ESA’s Redu center in Belgium, where a 20 m-diameter antenna can study the strength and shape of the navigation signals at high resolution.
“First, the various payload elements, especially the Passive Hydrogen Maser atomic clock, were warmed up, then the payload’s first ‘signal in space’ was transmitted,” said David Sanchez-Cabezudo, managing the test campaign.
“The satellite-broadcast L-band navigation signal is monitored using the large antenna at Redu, with experts from OHB and Surrey Satellite Technology Ltd – the payload manufacturer, based in Guildford, UK – also on hand to analyses how it performs over time.”
The first Galileo FOC navigation signal-in-space transmitting in the three Galileo frequency bands (E5/E6/L1) was tracked by Galileo Test User Receivers deployed at various locations in Europe, namely at Redu (B), ESTEC (NL), Weilheim (D) and Rome (I). The quality of the signal is good and in line with expectations.
The Search And Rescue (SAR) payload will be switched on in few days in order to complement the in-orbit test campaign.
The way forward
The same recovery maneuvers are planned for the sixth satellite, taking it into the same orbital plane but on the opposite side of Earth.
The decision whether to use the two satellites for Navigation and SAR purposes as part of the Galileo constellation will be taken by the European Commission based on the test results.
About Galileo
Galileo is Europe’s own global satellite navigation system. It will consist of 30 satellites and their ground infrastructure.
The definition phase and the development and In-Orbit Validation phase of the Galileo program were carried out by the European Space Agency (ESA) and co-funded by ESA and the European Union. This phase has created a mini-constellation of four satellites and a reduced ground segment dedicated to validating the overall concept.
The four satellites launched during the IOV phase form the core of the constellation that is being extended to reach Full Operational Capability (FOC).
The FOC phase is fully funded by the European Commission. The Commission and ESA have signed a delegation agreement by which ESA acts as design and procurement agent on behalf of the Commission.
Learn more about Galileo at: http://www.esa.int/Our_Activities/Navigation
—–
Follow redOrbit on Twitter, Facebook, Instagram and Pinterest.
redOrbit.com
offers Science, Space, Technology, Health news, videos, images and
reference information. For the latest science news, space news,
technology news, health news visit redOrbit.com frequently. Learn
something new every day.”
Source: http://www.redorbit.com/news/space/1113293100/galileo-satellite-recovered-and-transmitting-navigation-signals-120414/
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world. Anyone can join. Anyone can contribute. Anyone can become informed about their world. "United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
LION'S MANE PRODUCT
Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules
Mushrooms are having a moment. One fabulous fungus in particular, lion’s mane, may help improve memory, depression and anxiety symptoms. They are also an excellent source of nutrients that show promise as a therapy for dementia, and other neurodegenerative diseases. If you’re living with anxiety or depression, you may be curious about all the therapy options out there — including the natural ones.Our Lion’s Mane WHOLE MIND Nootropic Blend has been formulated to utilize the potency of Lion’s mane but also include the benefits of four other Highly Beneficial Mushrooms. Synergistically, they work together to Build your health through improving cognitive function and immunity regardless of your age. Our Nootropic not only improves your Cognitive Function and Activates your Immune System, but it benefits growth of Essential Gut Flora, further enhancing your Vitality.
Our Formula includes: Lion’s Mane Mushrooms which Increase Brain Power through nerve growth, lessen anxiety, reduce depression, and improve concentration. Its an excellent adaptogen, promotes sleep and improves immunity. Shiitake Mushrooms which Fight cancer cells and infectious disease, boost the immune system, promotes brain function, and serves as a source of B vitamins. Maitake Mushrooms which regulate blood sugar levels of diabetics, reduce hypertension and boosts the immune system. Reishi Mushrooms which Fight inflammation, liver disease, fatigue, tumor growth and cancer. They Improve skin disorders and soothes digestive problems, stomach ulcers and leaky gut syndrome. Chaga Mushrooms which have anti-aging effects, boost immune function, improve stamina and athletic performance, even act as a natural aphrodisiac, fighting diabetes and improving liver function. Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules Today. Be 100% Satisfied or Receive a Full Money Back Guarantee. Order Yours Today by Following This Link.
| Visits: | 1,707,562,639 |
| Stories: | 8,448,067 |
Whistler Blowers, Insiders
