It has been a tough year in spaceflight. The disintegration Sunday of an unmanned SpaceX Falcon 9 rocket bound for the International Space Station (ISS) was a first for that vehicle, but not for NASA, which has now seen three of the four spacecraft that ferry supplies to orbit fail in the past eight months.

In October an Antares rocket built by SpaceX rival Orbital ATK crashed and burned seconds after liftoff. Then in April Russia lost control of its Progress 59 cargo spacecraft shortly after launch, causing it to fall out of orbit and disintegrate in the atmosphere. Both unmanned freighters were carrying food, equipment and scientific research projects to the space station, just as SpaceX’s Dragon was on Sunday morning before the rocket carrying it broke apart during its climb from Florida's Cape Canaveral Air Force Station.

All three accidents appear to be completely unrelated, and space industry insiders have been repeating their usual mantra in the wake of the latest incident: Rocket science is rocket science, and a certain level of failure is unavoidable. “The astronauts are safe aboard the station and have sufficient supplies for the next several months,” NASA Administrator Charles Bolden said in a statement. “We will work closely with SpaceX to understand what happened, fix the problem and return to flight.”

Yet the rash of mishaps has many worried, especially those in Congress who are footing NASA’s bill and have lately been stingy in allocating funds for NASA’s partnership with commercial companies such as SpaceX. “We would be remiss to underestimate the gravity of the situation right now,” Florida Sen. Bill Nelson, who flew on the space shuttle himself in 1986 and is now the ranking member of the committee that oversees NASA, said in a statement.

The latest setback leaves NASA and its ISS partners with only one cargo freighter that is not currently undergoing an accident investigation—Japan’s H-II Transfer Vehicle (HTV), which is slated to make its next delivery in August. Before then, however, Russia will make another attempt with its Progress 60 spacecraft, due to launch on Friday. NASA itself does not have any spacecraft currently capable of flying to the station—after it retired the space shuttles, the agency outsourced cargo delivery to SpaceX and Orbital ATK. It also relies on Russia for its crew transportation for the time being. “NASA took themselves out of the game,” says Roger Handberg, a space policy expert at the University of Central Florida. “Right now we can send people to the space station, we just can’t send them anything to eat. The International Space Station has become in a sense a hostage to the inability of anyone to get it done.”

The accident also casts a shadow on NASA’s plans to use commercial spacecraft to carry astronauts to the space station starting in 2017, to avoid continuing to rely on Russia. The same Falcon 9 rocket and Dragon capsule that failed over the weekend are the basis of the vehicle that SpaceX plans to use to fulfill its $2.6-billion contract under NASA’s Commercial Crew Program. Space industry veteran Boeing has a separate $4.2-billion deal to transport astronauts, but despite its history, the company had been seen as lagging behind front-runner SpaceX in the Commercial Crew race. “Now the bloom goes a little bit off the SpaceX rose,” Handberg says.

Founded by CEO and Chief Technology Officer Elon Musk, the company’s relatively glamorous reputation may actually harm it in the wake of the accident, says Scott Pace, director of the Space Policy Institute at The George Washington University. “Public perceptions were hit less hard by the Orbital Sciences and Russian failures but because of the visibility that SpaceX claims, this hits public perception more. If one lives by the press release, one can be harmed by the press release.”

Public support for the private space industry also took a blow last October (just three days after the Orbital Sciences ATK mishap) when Virgin Galactic's suborbital space plane SpaceShipTwo crashed during a test flight, killing one of its pilots. An investigation into that disaster is still ongoing yet the company is forging ahead with its plans to fly tourists on brief arcs to the edge of space and back from its futuristic Spaceport America facility in New Mexico.

Despite all these setbacks, industry proponents remain optimistic. Commercial Spaceflight Federation President Eric Stallmer took his children to Florida over the weekend to view the latest SpaceX liftoff. “That’s the second time I’ve taken my kids to watch a launch and it’s had a failure.” He may not bring his children to more launches anytime soon, he says, but he told them to look on the bright side. “These things happen when you’re pushing the envelope in spaceflight, but there are more good days than there are bad.” Stallmer says he is confident SpaceX will bounce back. After all, this was the first major accident for the Falcon 9 rocket, which had flown 18 successful missions in a row until now—including six by-the-book cargo deliveries to the ISS.

Perhaps those are acceptable success rates for space missions—especially unmanned flights. But how many failures are too many? “There is this larger issue: Can we reach space with a reasonable rate of reliability?” says Roger Launius, space history curator at the Smithsonian National Air and Space Museum. “The industry would love to talk about eventually having airlinelike operations. Well, are we ever going to be able to achieve that with rockets? I don’t know.”