SpaceX Upgrades the Dragon Capsules for Propulsive Landing

It's not exactly a new feature, more like an ability that was put aside in the past and got renewed interest recently.  Back on September 27th, SpaceX announced a new capability for the Dragon spacecraft. Dragon now has built-in redundancy to propulsively land using its SuperDraco thrusters. In the unlikely event of a parachute failure, the propulsive landing could save the vehicle and potential crew from a rough landing or imminent danger. 

The concept of landing on the SuperDraco thrusters dates back to 2014, when the Commercial Crew Program was getting started.

SpaceX introduced the concept of a propulsive landing Dragon over ten years ago. When SpaceX revealed Dragon 2, it was marketed as capable of propulsively landing anywhere on Earth and was initially designed to land exclusively with the SuperDracos. However, SpaceX ultimately pursued the use of parachutes as the main form of recovery for Dragon 2 missions.

A Tweet from 2014 shows this:

The reasons come back to SpaceX's overarching goal of Rapid Reusability. 

Landing on a concrete landing pad on land rather than in the ocean has many advantages, particularly when it comes to the long-term reusability and refurbishment of Dragon capsules. When landing in the ocean, saltwater can corrode the aluminum body and carbon fiber bonds that Dragon is constructed of. Propulsively landing on Earth would have prevented invasive corrosion from occurring in the first place, making rapid reusability a much more achievable goal.

What’s more, landing Dragon propulsively would’ve also been safer for the crew when exiting the spacecraft. Getting astronauts out of a capsule is an extended process, especially when they have been exposed to microgravity for extended periods of time. The motion of ocean waves and the process of retrieving Dragon from the water has proven to be quite lengthy, and landing on a solid pad on land would have allowed recovery teams to approach and egress the crew inside Dragon substantially quicker.

The role of getting NASA approval for every aspect of the certification of the Dragon played a part in the decision to downplay the propulsive landing and emphasize using parachutes to splashdown in the ocean. 

With parachutes now serving as Dragon’s main landing system, propulsively landing Dragon was no longer a main focus of Dragon 2’s development. It was later revealed that NASA desired a higher “loss of crew” reliability rating for Dragon and felt more comfortable with a parachute landing system than a propulsive landing system. NASA also believed that the small openings in Dragon’s heat shield for the four extendable landing legs could lead to the quick formation of hotspots during reentry, potentially leading to the break up of the vehicle. 

Followers of SpaceX and the Crew Dragon may recall that in 2019, after a test mission of one capsule to the ISS, it was subjected to a test of its SuperDraco thrusters and exploded on the test stand less than one second before it was to have ignited its thrusters. It suffered an anomaly, NASA speak for "cratering explosion on the test stand".

Today, Crew Dragon is known to be an extremely reliable and well-tested vehicle — flying 15 successful crewed missions to the ISS and other low-Earth orbits and suffering little to no issues with its parachute landing system. During the Crew-9 pre-launch briefing, NASA announced that Dragon now had the capability to activate its SuperDraco engines and perform a propulsive landing if a failure of the parachutes were to occur. Should an anomaly with the parachutes occur, the four main parachutes would be cut and Dragon would ignite its eight SuperDraco engines to slowly perform a propulsive splashdown. NASA stated that such a landing would be “tolerable” for any crew inside Dragon.

SpaceX testing Dragon’s eight SuperDraco’s during a hover test in 2015. Image credit: SpaceX

Perhaps surprisingly, the propulsive landing system was available for the first time on Crew-7 in August 2023 and has been functional on all private SpaceX missions since then.  It's expected to be used for future NASA ISS crew missions.  Now I'm stoked to watch a returning Dragon spacecraft do a vertical propulsive landing at one of the poured concrete Landing Zones that returning Falcon 9 boosters have landed on.