Will Originate From The Same Launch Pad Used For Operational Missions

SpaceX is planning a Pad Abort Test for the manned version of its Dragon space capsule Wednesday. The company says it is the first critical flight test of the system.

The test will be conducted Wednesday, May 6, from SpaceX’s Space Launch Complex 40 (SLC-40) in Cape Canaveral, Florida. While the test is originating from the same launch pad used for operational missions, this is not an operational flight.

According to SpaceX, since this will be the first flight test of the company's new launch abort system, the odds of encountering delays or issues are high. But the company says the test doesn’t need to be perfect to be valuable. The primary objective is to capture as much data as possible as the data captured here will be key in preparing Crew Dragon for its first human missions in 2017.

A Pad Abort Test is a trial run for a spacecraft’s launch abort system (sometimes called a launch escape system). This system is designed to quickly get the crew and spacecraft away from the rocket in the event of a potential failure. It is similar to an ejection seat for a fighter pilot, but instead of ejecting the pilot out of the spacecraft, the entire spacecraft is “ejected” away from the launch vehicle.

SpaceX says previous launch abort systems have been powered by a rocket tower mounted on top of the spacecraft. During an emergency, the tower would ignite and essentially pull the spacecraft to safety. This works well while the spacecraft is on the launch pad and for a few minutes into ascent, but once the vehicle reaches a certain altitude, the system is no longer useful and must be discarded.

SpaceX’s launch abort system, however, is integrated directly into the spacecraft. This means Crew Dragon will have launch escape capability from the launch pad all the way to orbit.

The entire test is less than two minutes long, with Dragon traveling over one mile in the first 20 seconds alone. SpaceX says the planned sequence of events for the test is as follows:
- T-0: The eight SuperDracos ignite simultaneously and reach maximum thrust, propelling the spacecraft off the pad.
- T+.5s: After half a second of vertical flight, Crew Dragon pitches toward the ocean and continues its controlled burn. The SuperDraco engines throttle to control the trajectory based on real-time measurements from the vehicle’s sensors.
- T+5s: The abort burn is terminated once all propellant is consumed and Dragon coasts for just over 15 seconds to its highest point about 1500 meters (.93 mi) above the launch pad.
- T+21s: The trunk is jettisoned and the spacecraft begins a slow rotation with its heat shield pointed toward the ground again.
- T+25s: Small parachutes, called drogues, are deployed first during a 4-6 second window following trunk separation.
- T+35s: Once the drogue parachutes stabilize the vehicle, three main parachutes deploy and further slow the spacecraft before splashdown.
- T+107s: Dragon splashes down in the Atlantic Ocean about 1.4 miles downrange of the launch pad.
 
Crew Dragon will accelerate from 0 to nearly 100 mph in one second. 

As the first flight test of SpaceX’s launch abort system, every piece of data gathered moves the company closer to our first crewed flights in 2017. At a top level, SpaceX says it is looking to demonstrate the overall effectiveness of Crew Dragon’s launch escape system, along with a handful of more specific objectives:

- Sequencing.  Demonstrate proper sequencing of the pad abort timeline—particularly given that several critical commands need to execute in very short periods of time.
- Closed Loop Control.  Demonstrate the ability of the eight SuperDraco engines to respond in real time to incoming data in order to ensure Crew Dragon stays on the appropriate course.
- Trajectory Data.  Obtain accurate trajectory data both for maximum altitude as well as distance downrange.
- External and Internal Environments.  Obtain data on impact of various internal and external factors to Crew Dragon to help ensure safe conditions for crew transport.

SpaceX says there will be a dummy on board the spacecraft, but despite popular belief, his name is not "Buster." Buster the Dummy already works for a great show you may have heard of called MythBusters. SpaceX says its dummy prefers to remain anonymous ... for the time being.

Pending the outcome of the pad abort test, SpaceX will then conduct an in-flight abort test. With the in-flight abort, we will test the same launch abort system, however this time in mid-flight during an actual launch. Both the pad abort and in-flight abort will be challenging tests, but the data gathered here will be key to helping develop the company's crewed spacecraft designed to safely carry humans to low-Earth orbit.

(Images provided by SpaceX)

FMI: www.spacex.com