SpaceX CEO and Chief Designer Elon Musk has ordered the installation of contingency abort software into all future Dragon cargo spacecraft, providing them with an option to deploy their parachutes after an off-nominal launch scenario. Such software may have allowed the CRS-7 Dragon to save herself after she was thrown free of the failing Falcon 9 during June’s ill-fated launch.
The CRS-7 Dragon mission ended abruptly through no fault of her own, as her Falcon 9 v1.1 rocket suffered a major malfunction 139 seconds into ascent – resulting in the break-up of the launch vehicle.
The Dragon spacecraft actually survived the rocket’s mishap, as the Falcon 9’s second stage began to disintegrate via an overpressure event in the Second Stage, in turn freeing the spacecraft.
“Dragon actually survived not only the Second Stage overpressure but continued to communicate until the vehicle dropped below the horizon and out of range,” Mr. Musk confirmed.
However, Dragon’s fate was already sealed as she headed for an unsurvivable high-velocity impact into the Atlantic below.
“It is somewhat tragic that it, unfortunately, hit the water quite hard and is at the bottom of the ocean.
“We are actually trying to send a remote submersible down to the region where the debris hit the water and see if we can retrieve additional elements of debris to either confirm our initial conclusions or point us in a different direction,” Mr. Musk added, speaking about the ongoing investigation into the failure, believed to have been caused by a failed strut that released a helium pressurization system bottle (Composite Overwrapped Pressure Vessel) that led to the overpressure event.
SpaceX had focused on Dragon’s systems from a post-first stage ascent standpoint, ensuring her ability to deal with contingency events in space and during her return. Dealing with a first stage launch failure was not a consideration until after the CRS-7 event.
“The issue is that, in this case, Dragon is inert on ascent. The software to initiate the parachute deployment was not in Dragon,” added Mr. Musk. “That is probably the saddest thing about this, is that, with just a bit of different software, Dragon would have made it.”
That software relates to Dragon being able to open and release her nose cone – which remains in place during first stage ascent – in turn allowing for the deployment of her parachutes, the latter following the procedures of the nominal End Of Mission (EOM) events or during an abort from orbit.
“With the cargo Dragon, it (off-nominal ascent software) was just not something that had been done yet. It was on the agenda, but it hadn’t been done yet,” added Mr. Musk.
“For future missions, even for the cargo version of the Dragon spacecraft, we’re now including contingency software that, if something were to go wrong with the vehicle, Dragon will always attempt to save itself.”
This software inclusion will be live from the next Dragon – CRS-8, believed to be targetting the end of this year – onwards.
Dragon’s future crew variant – known as the Dragon 2 – has a burning ambition of returning home under the propulsive power of the SuperDraco thrusters, which also provide a Launch Abort capability during ascent. This capability will be tested during the Dragon 2 “In-Flight Abort test” that will be conducted under the Commercial Crew Program milestones.
During the initial missions, Dragon 2 will return home under chutes – something all Dragon missions will continue to have as a capability, with chutes eventually providing a backup role to the SuperDracos, if required.
“There are parachutes on Dragons, always. That’s how it normally lands. It (the software addition of deploying chutes in an off-nominal event) was certainly was planned for Dragon 2.
“One of the things we’ve decided to do is to advance the software that was meant for Dragon 2 into Dragon 1 so that if something like this were to happen in the future, the Dragon spacecraft would save itself.”
Had this launch failure occurred during a Dragon 2 mission, the Dragon would have had the extra capability of firing up the SuperDracos to increase the distance away from the failing Falcon 9.
“If it were Dragon 2, the system would have initiated an abort via the abort thrusters. So it would thrust itself away from the vehicle quite rapidly and then, once it was a decent distance away from the vehicle, would initiate parachutes to land in the ocean,” Mr. Musk noted.
“But, as I said, even Dragon 1 – which does not have the abort thrusters – survived the Second Stage overpressure. So, even with the Dragon 1 – without the abort thrusters – if it had initiated chute deployment, the cargo would have been saved, or a crew would have been saved, conversely.
“It was always baselined to be there for a crew mission.”
Dragon 2’s maiden flight into space won’t be crewed, with current manifest showing SpaceX plans to conduct the first test mission to the ISS via an uncrewed Dragon 2 mission, designated SpX-DM1, in December, 2016 – with the 30-day mission ending with a parachute assisted landing in the Pacific ocean.
This mission will make use of its capability, carrying cargo to the Station during its test flight.
SpaceX is then scheduled to conduct the SpX-DM2 crewed flight, launching in April of 2017 on a 14-day mission.
However, Mr. Musk has pointed to a flexible outlook with the potential for up to two flights being uncrewed before astronauts finally get to launch on the Dragon 2.
Such a second uncrewed mission could also provide an extra ISS resupply run boost, in tandem with a second dress rehearsal ahead the historic arrival of a crew onboard the new Dragon spacecraft.
(Images: via NASA, SpaceX, and L2’s SpaceX, including renderings created by L2 Artist Nathan Koga – Click here for full resolution F9, F9-R, FH, Dragon 2, BFR and MCT renderings and more – with those not official SpaceX images.)
(Click here: http://www.nasaspaceflight.com/l2/ – to view how you can support NSF’s running costs and access the best space flight content on the entire internet)