DART (Double Asteroid Redirection Test) | Falcon 9 Block 5

Featured image credit: SpaceX

Lift Off Time (Subject to change)	November 24, 2021 06:21 UTC November 23, 2021 22:21 PST
Mission Name	Double Asteroid Redirection Test (DART)
Launch Provider (What rocket company is launching it?)	SpaceX
Customer (Who’s paying for this?)	NASA
Rocket	Falcon 9 Block 5 B1063-3; 182 day turn around time
Launch Location	Space Launch Complex 4 East (SLC-4E), Vandenberg Space Force Base, California
Payload mass	684 kg (1,100 lb)
Where are the satellites going?	Dart will collide with Dimorphos at 6.6 km/s; initial orbit: heliocentric
Will they be attempting to recover the first stage?	Yes
Where will the first stage land?	~649 km downrange on Of Course I Still Love You Tug: TBD; Support: Go Quest
Will they be attempting to recover the fairings?	The fairing halves will be recovered from the water ~740km downrange by NRC Quest
Are these fairings new?	Yes
How’s the weather looking?	TBD
This will be the:	– 129th Falcon 9 launch – 70th Falcon 9 flight with a flight proven booster – 74th re-flight of a booster – 25th re-flight of a booster in 2021 – 95th booster landing – 26th launch for SpaceX in 2021 (same as 2020) – 18th SpaceX launch from SLC-4E – 117th orbital launch attempt of 2021
Where to watch	Official livestream

What’s This All Mean?

SpaceX will launch the Double Asteroid Redirection Test (DART) spacecraft atop a Falcon 9 Block 5, which will lift off from Space Launch Complex 4 East (SLC-4E), at the Vandenberg Space Force Base, in California. DART is the first ever kinetic impactor, meaning the spacecraft will attempt to demonstrate the ability to deflect the asteroid Didymos B by colliding with it at a high speed (approximately 6.6 km/s).

What Is DART?

The DART spacecraft is an impactor and contains no scientific payloads. The spacecraft is roughly a cylinder that is 12.5 meters tall and 2.4 meters wide. DART will have a mass of 670 kg at launch, but only 500 kg during impact.

The satellite is equipped with a sun sensor, a star tracker, and an aperture camera, which will be used to navigate to Didymos B. The spacecraft will navigate to the asteroid autonomously, expecting to arrive in September of 2022. DART is powered by the NASA Evolutionary Xenon Thruster (NEXT), which is an ion thruster that runs on Xenon.

DART will impact the asteroid Didymos B at a speed of 6.6 km/s (4.1 mi/s), which is expected to produce a change in velocity on the order of 0.4 mm/s. While a tiny change, this velocity change will cause a drastic change in the object’s orbit. The orbital period is expected to be reduced by approximately 10 minutes.

DART Secondary Spacecraft

Flying alongside DART, the Italian Space Agency is contributing the Light Italian CubeSat for Imaging of Asteroids (LICIACube), which will piggyback on DART. The cube-sat will deploy from the DART spacecraft 10 days before impact, and will be used to take photos of the impact and debris field.

What Is Falcon 9 Block 5?

The Falcon 9 Block 5 is SpaceX’s partially reusable two-stage medium-lift launch vehicle. The vehicle consists of a reusable first stage, an expendable second stage, and, when in payload configuration, a pair of reusable fairing halves.

First Stage

The Falcon 9 first stage contains 9 Merlin 1D+ sea level engines. Each engine uses an open gas generator cycle and runs on RP-1 and liquid oxygen (LOx). Each engine produces 845 kN of thrust at sea level, with a specific impulse (ISP) of 285 seconds, and 934 kN in a vacuum with an ISP of 313 seconds. Due to the powerful nature of the engine, and the large amount of them, the Falcon 9 first stage is able to lose an engine right off the pad, or up to two later in flight, and be able to successfully place the payload into orbit.

The Merlin engines are ignited by TEA-TEB, triethylaluminum and triethylboron . During static fire and launch the TEA-TEB is provided by the ground service equipment. However, as the Falcon 9 first stage is able to propulsively land three of the Merlin engines (E1, E5, and E9) contain TEA-TEB canisters to relight for the boost back, reentry, and landing burns.

Second Stage

The Falcon 9 second stage is the only expendable part of the Falcon 9. It contains a singular MVacD engine that produces 992 kN of thrust and an ISP of 348 seconds. The second stage is capable of doing several burns, allowing the Falcon 9 to put payloads in several different orbits.

For missions with many burns and/or long coasts between burns, the second stage is able to be equipped with a mission extension package. When the second stage has this package it has a grey strip, which helps keep the RP-1 warm, an increased number of composite over-wrapped pressure vessels (COPVs) for pressurization control, and additional TEA-TEB.

Falcon 9 Booster

The booster supporting DART is B1063. As DART is the booster’s third flight, it’ll change its designation to B1063-3.

B1063’s missions	Launch Date (UTC)	Turnaround Time (Days)
Sentinel-6	November 21, 2020	N/A
Starlink V1.0 L28	May 26, 2021	186
DART	November 24, 2021	182

Following stage separation, the Falcon 9 will conduct 2 burns. These burns will softly touch down the booster on SpaceX’s autonomous spaceport drone ship Of Course I Still Love You.

Falcon 9 Fairings

The Falcon 9’s fairing consists of two dissimilar reusable halves. The first half (the half that faces away from the transport erector) is called the active half, and houses the pneumatics for the separation system. The other fairing half is called the passive half. As the name implies, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics from the active half.

Both fairing halves are equipped with cold gas thrusters and a parafoil which are used to softly touch down the fairing half in the ocean. SpaceX used to attempt to catch the fairing halves, however, at the end of 2020 this program was canceled due to safety risks and a low success rate. On DART, SpaceX will attempt to recover one of the fairing halves from the water with their recovery vessel NRC Quest.

In 2021, SpaceX started flying a new version of the Falcon 9 fairing. The new “upgraded” version has vents only at the top of each fairing half, by the gap between the halves, whereas the old version had vents placed spread equidistantly around the base of the fairing. Moving the vents decreases the chance of water getting into the fairing, making the chance of a successful scoop significantly higher.

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DART COUNTDOWN

All times are approximate

HR/MIN/SEC	EVENT
00:38:00	SpaceX Launch Director verifies go for propellant load
00:35:00	RP-1 (rocket grade kerosene) loading underway
00:35:00	1st stage LOX (liquid oxygen) loading underway
00:16:00	2nd stage LOX loading underway
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

DART LAUNCH, LANDING, AND DEPLOYMENT

All times are approximate

HR/MIN/SEC	EVENT
00:01:12	Max Q (moment of peak mechanical stress on the rocket)
00:02:33	1st stage main engine cutoff (MECO)
00:02:36	Stage separation
00:02:44	1st stage engine starts
00:03:11	Fairing deployment
00:06:40	1st stage entry burn start
00:07:10	1st stage entry burn complete
00:08:06	2nd stage engine cutoff (SECO-1)
00:08:26	1st stage landing burn start
00:08:52	1st stage landing burn complete
00:28:37	2nd stage engine starts
00:29:30	2nd stage engine cutoff (SECO-2)
00:55:40	DART deploys