Falcon9 | ESA's Hera mission
Hera set to probe the lingering mysteries of a unique target among the 1.3 million known asteroids of our Solar System
SpaceX is targeting Monday, October 7 for Falcon 9’s launch of the ESA Hera mission to interplanetary transfer orbit from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida. Liftoff is targeted for 10:52 a.m. ET. If needed, a backup launch opportunity is available on Tuesday, October 8 at 10:46 a.m. ET.
Countdown
Hr/Min/Sec Event
00:38:00 SpaceX Launch Director verifies go for propellant load
00:35:00 RP-1 (rocket grade kerosene) loading begins
00:35:00 1st stage LOX (liquid oxygen) loading begins
00:16:00 2nd stage LOX loading begins
00:07:00 Falcon 9 begins engine chill prior to launch
00:01:00 Command flight computer to begin final prelaunch checks
00:01:00 Propellant tank pressurization to flight pressure begins
00:00:45 SpaceX Launch Director verifies go for launch
00:00:03 Engine controller commands engine ignition sequence to start
00:00:00 Falcon 9 liftoff
Due to the additional performance required to deliver the payload to an interplanetary transfer orbit, this mission marks the 23rd and final launch for this Falcon 9 first stage booster, which previously launched Crew-1, Crew-2, SXM-8, CRS-23, IXPE, Transporter-4, Transporter-5, Globalstar FM15, ISI EROS C-3, Korea 425, Maxar 1, ASBM, and 10 Starlink missions.
Launch and Deployment
Hr/Min/Sec Event
00:01:14 Max Q (moment of peak mechanical stress on the rocket)
00:02:41 1st stage main engine cutoff (MECO)
00:02:44 1st and 2nd stages separate
00:02:51 2nd stage engine starts (SES-1)
00:03:33 Fairing separation
00:07:39 2nd stage engine cutoff (SECO-1)
00:03:33 Fairing separation
00:07:39 2nd stage engine cutoff (SECO-1)
00:52:22 2nd stage engine starts (SES-2)
00:54:00 2nd stage engine cutoff (SECO-1)
01:16:02 ESA’s Hera satellite deploys
There’s a mystery out there in deep space – and solving it will make Earth safer. That’s why the European Space Agency’s Hera mission is taking shape – to go where one particular spacecraft has gone before.
On 26 September 2022, moving at 6.1 km/s, NASA’s DART spacecraft crashed into the Dimorphos asteroid. Part of our Solar System changed. The impact shrunk the orbit of the Great Pyramid-sized Dimorphos around its parent asteroid, the mountain-sized Didymos.
This grand experiment was performed to prove we could defend Earth against an incoming asteroid, by striking it with a spacecraft to deflect it. DART succeeded. But that still leaves many things scientists don’t know: What is the precise mass and makeup of Dimorphos? What did the impact do to the asteroid? How big is the crater left by DART’s collision? Or has Dimorphos completely cracked apart, to be held together only by its own weak gravity?
That’s why we’re going back – with ESA’s Hera mission. The spacecraft will revisit Dimorphos to gather vital close-up data about the deflected body, to turn DART’s grand-scale experiment into a well-understood and potentially repeatable planetary defence technique.
The mission will also perform the most detailed exploration yet of a binary asteroid system – although binaries make up 15% of all known asteroids, one has never been surveyed in detail.
Hera will also perform technology demonstration experiments, including the deployment ESA’s first deep space ‘CubeSats’ – shoebox-sized spacecraft to venture closer than the main mission then eventually land – and an ambitious test of 'self-driving' for the main spacecraft, based on vision-based navigation.
Hera Spacecraft:
Spacecraft are among the most complex machines ever built, so need to be broken down into sets of subsystems, and this video shows how ESA and European industry put together Hera
Hera’s chemical propulsion subsystem is what moves it through space, while its electrical power subsystem supplies and regulates electrical power throughout the spacecraft as needed. Its data handling subsystem sends commands and stores data while its electrical harness is all the wiring needed to interlink its component elements.
The spacecraft structural subsystem forms its ‘body’: a central carbon fibre reinforced polymer body can be thought of as Hera’s backbone, from which aluminium honeycomb panels are attached. Upon these panels are hosted the communication subsystem that allows Hera to transmit and receive signals to and from Earth – supplemented by the inter-satellite links used to communicate with its two CubeSats once deployed – as well as Hera’s guidance, navigation and control equipment.
Keeping the spacecraft supplied with electrical power are its twin 5-m long solar arrays flanking Hera. Atop its cube-shaped body on the mission’s ‘Asteroid Deck’ are hosted the Deep Space Deployers that will eject the Juventas and Milani CubeSats in the vicinity of its target asteroid, near its redundant Asteroid Framing Cameras and other key instruments: its Thermal Infrared Imager for nightside asteroid observations and its PALT laser rangefinder to measure Hera’s distance from the asteroid’s surface.
HyperScout H is a hyperspectral imager to prospect the asteroid, while the Spacecraft Monitoring Camera will survey the Asteroid Deck itself, which will be especially useful to track the CubeSat deployments. Supplementary scientific data will be gathered via a radio science experiment as part of the communication subsystem.
In the last phase of its mission Hera will perform an autonomous navigation experiment guided by visual imaging of asteroid surface features, made possible by a dedicated image processing unit. Then comes the thermal control subsystem to maintain Hera at a benign operating temperature amid the extreme conditions of space: this includes multi-layer insulation, which gives spacecraft their distinct ‘Christmas wrapping’ appearance plus radiators beside its solar arrays, which are used to radiate unwanted heat into cold space.
Hera journey:
By the end of Hera’s observations, Dimorphos will become the best studied asteroid in history, through Hera – we are teaching ourselves what we can do to reduce this hazard and make space safer.