DART

 

The Double Asteroid Redirect Test (DART) was NASA's successful test on September 26, 2022 of its plan to defend Earth from an asteroid's on collision course with our planet.

DART spacecraft zeroed in on Dimorphos, Didymos little moon which is 160 m in diameter and at a distance of 6.8 million miles or 11 million kilometers from Earth.  It stroke the little asteroid at a speed of 14,000 miles per hour hoping to divert from its orbit.

A picture of the little asteroid Dimorphos taken 2 min before the impact shows in great detail rocks on its surface.

Images from James Webb telescope showed a vast cloud of dust indicating a much larger force of the impact that it was expected.  The images were similar to those obtained by the Italian Space agency LICIAcube the little craft that separated from DART moments before its impact on Dimorphos.  NASA announced on Oct 11, 2022 DART's mission proved successful in adjusting the trajectory of Dimorphos, suggesting that a deadly space rock could be deflected in the future.  Before DART's impact it took the little asteroid 11 hours and 55 min to orbit its Didymos.  The spacecraft's impact changed the smaller asteroid's orbit by 32 min. 

Solar sailing

Solar sails have been long-discussed as a way to propel spacecraft.  The sails exploit the fact that solar wind exerts pressure on a mirrored surface.   This can be used for propulsion in a way that is akin to sails used by sailboats.

LightSail® is a solar sail project from the Planetary Society that has championed solar sailing for decades. The Society’s LightSail-2 spacecraft, launched 25 June 2019, is the first spacecraft in Earth’s orbit propelled solely by sunlight. On 31 July 2019, the LightSail-2’s orbit was raised, showing that solar sailing is a viable means of propulsion for CubeSats—small, standardised spacecraft that are part of a global effort to lower the cost of space exploration.

 The image above shows LightSail-2's sail after its deployment.

Hayabusa heading home

Japan's Hayabusa-2 spacecraft has departed from the asteroid Ryugu with samples of its soil and begun its year-long journey back to Earth. 

Hayabusa-2 was launched in 2014. Three and a half years later, it reached the asteroid Ryugu, located about 300 million km (190 million miles) from Earth.  The spacecraft is expected to return to Earth in December 2020, dropping a capsule containing the rock samples in the South Australian desert.  

Following its arrival in June 2018, the spacecraft made touchdowns twice, collecting data and rock samples from the Ryugu - a primitive space rock leftover from the early days of the Solar System

Scientists believed these would be more pristine samples, since they would not have been exposed to the harsh environment of space. They were the first underground samples collected from an asteroid in space history.

While asteroids are some of the oldest objects in space, Ryugu belongs to a particularly primitive type of space rock, and may contain clues about the conditions and chemistry of the early days of the Solar System - some 4.5 billion years ago.