NASA DART and ESA Hera to study deflecting asteroids via spacecraft impact

ESA and NASA are testing defenses against an asteroid threat:

Earth’s first mission to a binary asteroid,
for planetary defence

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 ‘Didymoon’. 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.

25 June 2018: Planning for humankind’s first mission to a binary asteroid system has entered its next engineering phase. ESA’s proposed Hera mission would also be Europe’s contribution to an ambitious planetary defence experiment.

Named for the Greek goddess of marriage, Hera would fly to the Didymos pair of Near-Earth asteroids: the 780 m-diameter mountain-sized main body is orbited by a 160 m moon, informally called ‘Didymoon’, about the same size as the Great Pyramid of Giza.

“Such 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,”

explains Hera manager Ian Carnelli.

“The extremely low-gravity environment also presents new challenges to the guidance and navigation systems. Fortunately we can count on the unique experience of ESA’s Rosetta operations team which is an incredible asset for the Hera mission.”

The smaller Didymoon is Hera’s 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.

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.

A NASA mission called the Double Asteroid Redirection Test, or DART, is due to collide with it in October 2022. The impact will lead to a change in the duration of Didymoon’s 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.

“Essential information will be missing following the DART impact – which is where Hera comes in,” adds Ian. “Hera’s close-up survey will give us the mass of Didymoon, the shape of the crater, as well as physical and dynamical properties of Didymoon.

“This 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.”

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’s gravitational field would be swamped by that of its larger partner.

Hera uses infrared to scan impact crater.

Instead, Hera imagery will be used to track key landmarks on the surface on the bigger body, ‘Didymain’, such as boulders or craters. By measuring the ‘wobble’ 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%.

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 of the asteroid.

“Hera benefits from more than five years of work put into ESA’s former Asteroid Impact Mission,” comments Ian. “Its main instrument is a replica of an asteroid imager already flying in space – the Framing Camera used by NASA’s Dawn mission as it surveys Ceres, which is provided by the German Aerospace Center, DLR.

“It would also carry a ‘laser radar’ lidar for surface ranging, as well as a hyperspectral imager to characterise surface properties. In addition, Hera will deploy Europe’s first deep space CubeSats to gather additional science as well as test advanced multi-spacecraft intersatellite links.”

NASA’s DART mission meanwhile has passed its preliminary design review and is about to enter its ‘Phase C’ detailed design stage.

In 2022, NASA’s Double Asteroid Redirection Test (DART) collides with the smaller body of the Didymos binary asteroid system in an attempt to measurably shift its orbit. ESA’s Hera mission, now under study, will examine the aftermath of this impact to help determine whether humans can deflect threatening asteroids.



A blue sand dune on Mars

Mars has lots of weird and wonderful features on its surface. For example, here is one highlighted by NASA last week:

Once in a Blue Dune

Sand dunes often accumulate in the floors of craters. In this region of Lyot Crater, NASA’s Mars Reconnaissance Orbiter (MRO) shows a field of classic barchan dunes on Jan. 24, 2018.

Just to the south of the group of barchan dunes is one large dune with a more complex structure. This particular dune, appearing like turquoise blue in enhanced color, is made of finer material and/or has a different composition than the surrounding.

The map is projected above at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 34.7 centimeters (13.7 inches) per pixel (with 1 x 1 binning); objects on the order of 104 centimeters (40.9 inches) across are resolved.] North is up.

This is a stereo pair with ESP_053406_2295.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.

Image Credit: NASA/JPL-Caltech/Univ. of Arizon

Image download options

The Space Show this week – June.25.2018

The guests and topics of discussion on The Space Show this week:

1. Monday, June 25, 2018; 2-3:30 pm PDT (4-5:30 pm CDT, 5-6:30 pm EDT): We welcome Dr. John Cramer to the program to discuss multiple topics in physics and much more.

2. Tuesday, June 26, 2018: 7-8:30 pm PDT; 9-10:30 pm CDT; 10-11:30 pm EDT: We welcome back Dr. Ajay Kothari to discuss his latest return to the Moon plan and program.

3. Wednesday, June 27, 2018: Hotel Mars.  Dr. William Farrand What Happened to Opportunity?

Hotel Mars is pre-recorded by John Batchelor. It is archived on The Space Show site after John posts it on his website.

4. Friday, June 29, 2018; 9:30 am -11 am PDT, (12:30 -2 pm EDT; 11:30 am -1 pm CDT): We welcome back Dr. Anita Sengupta to discuss the Cold Atom Lab, Hyperloop and more.

5. Sunday, July 1, 2018: 12-1:30 pm PDT; 2-3:30 pm CDT; 3-4:30 pm EDT. OPEN LINES. First time callers welcome, all space, science, STEM and STEAM calls welcome. We want to hear from you. What’s on your mind?

See also:
* The Space Show on Vimeo – webinar videos
* The Space Show’s Blog – summaries of interviews.
* The Space Show Classroom Blog – tutorial programs

The Space Show is a project of the One Giant Leap Foundation.

The Space Show - David Livingston
David Livingston


Video: TMRO Orbit 11.25 – The evolution of galaxies with Dr. Charles Liu

The latest episode of TMRO Space is now available on line: The evolution of galaxies with Dr. Charles Liu – Orbit 11.25 – TMRO

Dr. Charles Liu joins us to talk about the observable evolution of galaxies, quasar hunting and has some inspiring words about science communication.

Launch and news topics covered:


  • Russia Launches GLONASS-M Satellite

Space News:

  • Einstein you genius
  • B-b-b-blackhole and the jets
  • The EU is taking down the trash is viewer supported:

TMRO shows are crowd funded. If you like this episode consider contributing to help us to continue to improve. Head over to for funding levels, goals and all of our different rewards!


Rocket Lab to launch an Electron with 5 payloads including Irvine CubeSat built by high schoolers

This evening US time and Saturday afternoon New Zealand time, Rocket Lab will attempt to launch the third Electron rocket into orbit.

The Electron on the pad at Mahia. (Photo credits Kieran_Fanning)

The rocket is to lift off from the Mahia Peninsula on the east coast of New Zealand‘s North Island. You can watch the launch via the webcast.

The vehicle is carrying four payloads for commercial companies plus the Irvine CubeSat built by high school students in Irvine, California.

The Irvine CubeSat Program is a revolutionary STEM initiative based in Irvine, California. With over 100 members from six public high schools, the program collectively strives to assemble, test, and launch a solar powered CubeSat. It aims to inspire the next generation of innovative thinkers, creators, programmers, and explorers.

Here is a video about the program:

The company’s press kit (pdf) has lots of information about the mission. See also Rocket Lab set for first operational Electron launch with five payload elements –