ESA successfully completes controlled re-entry of its Aeolus satellite

Engineers for the European Space Agency (ESA) yesterday successfully completed the controlled re-entry of its Aeolus satellite above Antarctica, where it burned up in the atmosphere.

The spacecraft would never have hit the ground had its re-entry — which would have happened anyway in just a matter of weeks — been allowed to happen in an uncontrolled manner. However, ESA decided to use the satellite to practice disposal techniques it wishes to make standard for all future satellites, especially those whose orbit keeps them in space long after their mission is finished.

SpaceX declines to shift Starlink satellite to avoid collision

When European Space Agency (ESA) engineers realized there was a greater than normal chance that a new SpaceX Starlink satellite could collide with ESA’s already orbiting Aeolus satellite, they asked SpaceX to shift its orbit, only to have SpaceX decline.

According to Holger Krag, head of the Space Debris Office at ESA, the risk of collision between the two satellites was 1 in 1,000 – ten times higher than the threshold that requires a collision avoidance maneuver. However, despite Aeolus occupying this region of space nine months before Starlink 44, SpaceX declined to move their satellite after the two were alerted to the impact risk by the U.S. military, who monitor space traffic. “Based on this we informed SpaceX, who replied and said that they do not plan to take action,” says Krag, who said SpaceX informed them via email – the first contact that had been made with SpaceX, despite repeated attempts by Krag and his team to get in touch since Starlink launched. “It was at least clear who had to react. So we decided to react because the collision was close to 1 in 1,000, which was ten times higher than our threshold.”

As to why SpaceX refused to move their satellite, that is not entirely clear (the company did not respond to a request for comment). Krag suspected it could be something to do with SpaceX’s electric propulsion system, which “maybe is not reacting so fast” as the chemical propulsion on board Aeolus.

The article is clearly spun to make SpaceX look bad, though based on the stated facts the company shot itself in the foot quite ably. If their propulsion system could not have done the job as well as the other satellite, they should have simply said so and worked with ESA to get the issue fixed, rather than simply saying they would do nothing.

Arianespace’s Vega launches European satellite to study the Earth’s winds

Arianespace’s Vega rocket has successfully launched a European satellite dubbed Aeolus designed to study the Earth’s winds.

Funded by the European Space Agency and built by Airbus Defense and Space, the 480 million euro ($550 million) Aeolus mission is nearly two decades in the making. Since receiving ESA’s formal go-ahead in 2002, Aeolus has suffered numerous delays as engineers encountered problems with the mission’s laser instrument.

Aeolus will gather the first comprehensive worldwide measurements of wind speed — over oceans and land masses — from Earth’s surface to an altitude of nearly 100,000 feet (30 kilometers).

Data collected by the Aeolus satellite will be fed into numerical weather prediction models, replacing simulated “boundary conditions” in the computers models with near real-time measurements from space.

The updated leader board for the 2018 launch standings:

22 China
15 SpaceX
8 Russia
5 Arianespace

In the national race, the U.S. and China remained tied at 22.