Zuma was a remarkable achievement for SpaceX, and also something of a thorny subject. Originally reaching the public eye in October 2017 and slated for a launch by November 30, 2017, the unusually quick (from a public point of view) turnaround from entering the manifest till launch was a great demonstration of how resilient SpaceX has become. They were able to move around some launches and boosters between customers to accommodate the payload. Unfortunately, the launch did not occur in 2017 due to manufacturing concerns with a different client’s fairing necessitating airlifting Zuma’s fairings back to Hawthorne, CA for inspection.

Zuma did eventually launch on January 7, 2018 at 8pm local time. The launch was rather typical for classified cargo. The first stage lifted the second stage and cargo flawlessly and, following MECO and stage separation, the live video stream followed the first stage back to Landing Zone 1 for a perfect landing. Meanwhile, second stage operations were performed in private. It appeared to be a perfect mission and life went on with most of the space community focusing on the upcoming Falcon Heavy static fire tests.

The SpaceX web cast for the Zuma launch (SpaceX)

Several hours later, unconfirmed rumors began springing up stating that the launch was, in fact, not a success. These rumors, though, didn’t point to anything or anyone solid that could confirm what happened, just anonymous sources. Some indicated that the payload never left the second stage and fell back into the atmosphere when the stage deorbited. Others indicated that the payload did in fact separate and was actually in orbit, just not responding. The fact that the satellite was given a designation of USA 280 on the Space-Track.org website should confirm that the payload achieved at least one orbit. While this article won’t go too much in depth about the subject, The Everyday Astronaut covers what we really know vs what is guess work in the following video.

The Everyday Astronaut (reluctantly) covers the speculation surrounding Zuma (The Everyday Astronaut)

Quickly, these rumors became articles, with several well-known SpaceX critics taking the precious few bits of information about Zuma, along with some assumptions and guesses portrayed as facts, and forging sensationalist articles touting a SpaceX mission failure and doubts about SpaceX reliability. One such article published on Forbes was even partially read into the congressional record by Representative Mo Brooks (Alabama) during a hearing regarding Commercial Crew systems development. It should be noted that Mo Brooks has been a strong defender of ULA, a competitor of SpaceX, and has even supported multi-year monopolies in favor of ULA in the past.

To be clear, if these rumors were verified and SpaceX had indeed been responsible for a loss of mission, concerns about reliability and the Falcon 9s design would be very much justified. SpaceX has lost two Falcon 9 vehicles in the past (the CRS-7 mission in 2015 and the AMOS-6 test anomaly in 2016). These two losses hurt the company financially and were a setback at the time for their reputation and their attempts at increasing their launch cadence. However, SpaceX learned from these losses and made improvements to the Falcon 9 launch vehicle as well as the company processes.

Official Statement from Gwynne Shotwell (President, CEO of SpaceX) regarding Zuma

On January 9, 2018, SpaceX released an official statement informing that the Falcon 9 performed correctly during the Zuma launch and that the company will be continuing with their manifest for the year. This statement was quickly followed by tweets from SES and Matt Desch (Iridium) defending SpaceX and expressing confidence in their upcoming launches. However, members of the House space subcommittee repeatedly brought up the issue of Zuma during the hearing. The only reply that Dr. Koenigsmann could give was that “Falcon 9 performed as specified,” and variants on that theme.

Dr. Hans Koenigsmann testifying before the House space subcomittee

However, Zuma was not the only concern raised during that hearing. In addition to that launch and the two losses mentioned earlier, concern was raised about the COPV (composite overwrapped pressure vessel) technology used by the Falcon 9 inside the first and second stage LOX tanks as well as the proposed process of late loading the fuel into the rocket while astronauts are on board. Both of these are definite technical issues that need to be put to rest, although they are not necessarily matters that should shed doubt on SpaceX’s reliability or commitment to safety.

The COPVs were the apparent proximate cause of the AMOS-6 testing anomaly. One of the vessels appears to have ignited, leading to the conflagration that destroyed the rocket. The ultimate cause has not been absolutely determined, and likely can’t be, but is thought to be due to an improper weave or lamination issue in the composite overwrap leading to liquid oxygen entering the space between weaves and freezing, causing enough friction to ignite the overlay material.

A video illustrating the process of creating a COPV (Interorbital Systems)

In response to these findings, NASA and SpaceX have been working on a COPV-2 design. This design would protect against SOX formation leading to a detonation of the rocket. As a secondary plan, NASA has also requested that SpaceX investigate the feasibility of using ICONEL based tanks instead of COPVs for the storage of Helium inside the LOX tanks. The end result of this research will likely lead to improved COPV technology that will have impact extending outside of the Falcon 9 program and will lead to greater reliability on all SpaceX vehicles.

The late loading of fuel is a contentious topic in the space community. The idea of fueling a rocket with highly explosive propellant while the astronauts are strapped into their capsule on top of said rocket is considered to be too dangerous by most traditional space engineers. The “correct” way is to fill the rocket first, then have the astronauts and support crew approach the rocket and secure the astronauts and late load cargo into the capsule while continuously topping off the fuel as it boils off.

The challenge here is that the Falcon 9 is designed to use “densified propellant”. Specifically, the liquid oxygen that they use is cooled far below its boiling point, making it denser and allowing for more LOX to be stored in the tank. The trade off is that the rocket cannot sit for several hours topping off the LOX that has boiled away. Instead, the propellant loading is timed such that launch happens only a few minutes after the tanks have been filled. (Check out this detailed estimate of the Falcon 9 countdown)

NASA has not dismissed the SpaceX approach for late loading of fuel out of hand. In part, this is because of the integrated flight abort system on the crew Dragon spacecraft. This launch abort system provides abort functionality for the entirety of the trip to orbit, including “Abort to Orbit” functionality if sufficient height has already been achieved. It would certainly protect the astronauts from any sort of explosion while on the pad. However, it is a new approach that has to be fully researched and understood before NASA is willing to risk the lives of their astronauts.