October 23, 2011

Spacex completes another milestone towards manned Spacex launches and Europe launches first two commercial GPS satellites

1. Universe Today - Space Exploration Technologies (SpaceX) is now one more step closer to sending astronauts to orbit. The commercial space firm announced today that it has completed a successful review of the company’s launch abort system (LAS). SpaceX’s LAS, dubbed “DragonRider” is designed differently than abort systems that have been used in the past.

The United States is paying Russia an estimated $63 million per seat on its Soyuz spacecraft. SpaceX has estimated that, by comparison, flights on a man-rated version of its Dragon spacecraft would cost approximately $20 million. Despite the dramatically lower cost, SpaceX has emphatically stated that safety is one of the key drivers of its spacecraft.
The DragonRider launch abort system would allow astronauts to be safely pulled away from the Falcon 9 launch vehicle in the advent of an emergency. Image Credit: SpaceX

2. BBC News - The European Space Agency launched its first two Galileo global navigation system satellites.

Galileo is designed for civilian purposes and aims to end Europe’s reliance on GPS. The system is expected to start operating in 2015. While a position fixed by the publicly available GPS signal might have an error of about 10 meters, Galileo’s designers promise one-meter accuracy.

The plan is to make the different GPS systems interoperable, meaning the biggest, most obvious benefit to users will simply be the fact that they can see more satellites in the sky at any one time.

So, as the decade progresses and the number of spacecraft in orbit increases, the performance of all sat-nav devices should improve. Fixes ought to be faster and more reliable, even in testing environments such as big cities where tall buildings will often obscure a receiver's view of a transmitting spacecraft.

1. A large antenna will transmit signals to users on the ground
2. Distress signals are picked up by a search and rescue antenna
3. Another antenna receives information on the status of Galileo
4. The spacecraft is controlled from the ground via telecommands
5. Sensors make sure the satellite is always pointing at Earth
6. Further sensors keep an eye on where the Sun is in the sky
7. A laser retroreflector can determine the satellite's exact height
8. Radiators expel excess heat to protect electronics from overheating

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