{"id":16289,"date":"2018-06-26T12:48:50","date_gmt":"2018-06-26T16:48:50","guid":{"rendered":"http:\/\/hobbyspace.com\/Blog\/?p=16289"},"modified":"2018-06-26T12:48:50","modified_gmt":"2018-06-26T16:48:50","slug":"nasa-dart-and-esa-hera-to-study-deflecting-asteroids-via-spacecraft-impact","status":"publish","type":"post","link":"https:\/\/hobbyspace.com\/Blog\/?p=16289","title":{"rendered":"NASA DART and ESA Hera to study deflecting asteroids via spacecraft impact"},"content":{"rendered":"

ESA and NASA are testing defenses against an asteroid threat:<\/p>\n

Earth\u2019s first mission to a binary asteroid,
\nfor planetary defence<\/a><\/strong><\/p>\n

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Hera is the European contribution to an ESA-NASA double-spacecraft mission intended to test whether a kinetic deflection technique can be used to shift the orbit of an asteroid. Target of the mission is a double asteroid system, called Didymos, which will come a comparatively close 11 million km to Earth in 2022. The 800-m diameter main body is orbited by a 170-m moon, informally called \u2018Didymoon\u2019. In 2022 NASA will first perform a kinetic impact on the smaller of the two bodies, then Hera will follow-up with a detailed post-impact survey that will turn this grand-scale experiment into a well-understood and repeatable planetary defence technique.<\/em><\/figcaption><\/figure>\n

25 June 2018<\/strong>:\u00a0Planning for humankind\u2019s first mission to a binary asteroid system has entered its next engineering phase. ESA\u2019s proposed Hera mission would also be Europe\u2019s contribution to an ambitious planetary defence experiment.<\/p>\n

Named for the Greek goddess of marriage,\u00a0Hera<\/a>\u00a0would fly to the Didymos pair of Near-Earth asteroids:\u00a0the 780 m-diameter mountain-sized main body is orbited by a 160 m moon, informally called \u2018Didymoon\u2019, about the same size as the Great Pyramid of Giza.<\/p>\n

\u201cSuch a binary asteroid system is the perfect testbed for a planetary defence experiment but is also an entirely new environment for asteroid investigations. Although binaries make up 15% of all known asteroids, they have never been explored before, and we anticipate many surprises,\u201d <\/em><\/p>\n

explains Hera manager Ian Carnelli.<\/p>\n

\u201cThe extremely low-gravity environment also presents new challenges to the guidance and navigation systems. Fortunately we can count on the unique experience of ESA\u2019s Rosetta operations team which is an incredible asset for the Hera mission.\u201d<\/em><\/p>\n

The smaller Didymoon is Hera\u2019s main focus: the spacecraft would perform high-resolution visual, laser and radio science mapping of the moon, which will be the smallest asteroid visited so far, to build detailed maps of its surface and interior structure.<\/p>\n

https:\/\/dlmultimedia.esa.int\/download\/public\/videos\/2018\/06\/034\/orig-1806_034_AR_EN.mp4<\/a><\/video><\/div>\n

By the time Hera reaches Didymos, in 2026, Didymoon will have achieved historic significance: the first object in the Solar System to have its orbit shifted by human effort in a measurable way.<\/p>\n

A NASA mission called the Double Asteroid Redirection Test<\/a>, or DART, is due to collide with it in October 2022. The impact will lead to a change in the duration of Didymoon\u2019s orbit around the main body. Ground observatories all around the world will view the collision, but from a minimum distance of 11 million km away.<\/p>\n

\u201cEssential information will be missing following the DART impact \u2013 which is where Hera comes in,\u201d adds Ian. \u201cHera\u2019s close-up survey will give us the mass of Didymoon, the shape of the crater, as well as physical and dynamical properties of Didymoon.<\/em><\/p>\n

\u201cThis key data gathered by Hera will turn a grand but one-off experiment into a well-understood planetary defence technique: one that could in principle be repeated if we ever need to stop an incoming asteroid.\u201d<\/em><\/p>\n

The traditional method of estimating the mass of a planetary body is to measure its gravitational pull on a spacecraft. That is not workable within the Didymos system: Didymoon\u2019s gravitational field would be swamped by that of its larger partner.<\/p>\n

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Hera uses infrared to scan impact crater.<\/em><\/figcaption><\/figure>\n

Instead, Hera imagery will be used to track key landmarks on the surface on the bigger body, \u2018Didymain\u2019, such as boulders or craters. By measuring the \u2018wobble\u2019 Didymoon causes its parent, relative to the common centre of gravity of the overall two-body system, its mass could be determined with an accuracy over 90%.<\/p>\n

Hera will also measure the crater left by DART to a resolution of 10 cm, accomplished through a series of daring flybys, giving insight into the surface characteristics and internal composition\u00a0of the asteroid.<\/p>\n

\u201cHera benefits from more than five years of work put into ESA\u2019s former Asteroid Impact Mission,\u201d comments Ian. \u201cIts main instrument is a replica of an asteroid imager already flying in space \u2013 the Framing Camera used by NASA\u2019s Dawn mission as it surveys Ceres, which is provided by the German Aerospace Center,\u00a0DLR.<\/em><\/p>\n

\u201cIt would also carry a \u2018laser radar\u2019 lidar for surface ranging, as well as a hyperspectral imager to characterise surface properties. In addition, Hera will deploy Europe\u2019s first deep space CubeSats to gather additional science as well as test advanced multi-spacecraft intersatellite links.\u201d<\/em><\/p>\n

NASA\u2019s DART mission meanwhile has passed its preliminary design review and is about to enter its \u2018Phase C\u2019 detailed design stage.<\/p>\n

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In 2022, NASA\u2019s Double Asteroid Redirection Test (DART) collides with the smaller body of the Didymos binary asteroid system in an attempt to measurably shift its orbit.\u00a0ESA\u2019s Hera mission, now under study, will examine the aftermath of this impact to help determine whether humans can deflect threatening asteroids.<\/em><\/figcaption><\/figure>\n

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