After the explosion in September of one of its rockets, SpaceX is now ready to get back into the business of sending payloads to space, the company announced Monday, with its next rocket headed to orbit as soon as Sunday.
For the second year in a row, a SpaceX Falcon 9 rocket is in line to become the first blastoff of the year from Vandenberg Air Force Base in northern Santa Barbara County, assuming favorable weather and no last-minute glitches. Last year, a Falcon rocket also kicked off a new year of launches from Vandenberg.
SpaceX, or Space Exploration Technologies Corp., announced plans for a departure from Space Launch Complex-4 on South Base, with liftoff planned for 10:28 a.m. The rocket will carry 10 Iridium Next spacecraft to begin building the second-generation constellation for a satellite-phone system.
The roar and thin yellow contrails from Vandenberg launches can usually be heard and seen in San Luis Obispo County, especially the South County, depending on weather and the rocket’s trajectory.
While technical troubles appear to have been resolved after the Sept. 1 explosion during a static fire test in Florida, the mission may encounter another hurdle to departure Sunday — a massive winter storm setting its sights on the Central Coast this weekend.
The subtropical system is expected to bring heavy rain to the region, the National Weather Service said.
“While the details on duration, magnitude and location of this moisture plume will become more clear through the week, there is the potential for a heavy rain event across Southwest California next weekend which could pose significant flash flood with mud and debris flow issues across Southwest California,” the NWS added.
What went wrong in Florida
The Vandenberg launch marks a return to flight for Falcon following a Sept. 1 explosion during a static fire test at Cape Canaveral Air Force Station, Florida.
The cascade of explosions that destroyed the rocket on the launchpad was perplexing and concerning because it occurred during what is usually regarded as a safer portion of operations — the fueling of propellants — about eight minutes before the ignition of the engines for a planned test. (The launch had been scheduled for two days later.)
The trouble appeared to start near the liquid oxygen tank on the second stage of the two-stage rocket, and in less than a tenth of a second, that section was in flames, followed by the destruction of the entire rocket and a $200 million communications satellite whose customers included Facebook, which had planned to use it to expand internet services in Africa.
Under federal laws, investigations into such explosions are led by the company that built the rocket, not by a government agency. The investigation panel included representatives of the Federal Aviation Administration, the United States Air Force, NASA and the National Transportation Safety Board. Falcon 9 rockets are used to carry NASA cargo to the International Space Station and are to provide transportation for astronauts beginning in 2018. SpaceX is also competing to win contracts to launch Department of Defense spy satellites.
With few obvious clues to the explosion, the company initially considered hypotheses like sabotage, that a sniper had fired a shot rupturing the oxygen tank from the roof of a competitor’s building nearby.
“The accident investigation team worked systematically through an extensive fault tree analysis,” SpaceX said in a statement.
The investigation narrowed in on three helium containers within the second-stage liquid oxygen tank. The containers consist of an aluminum liner with an outer layer of strong carbon fibers. During launch, as the liquid oxygen is consumed, the helium is heated and released to maintain pressure within the tank.
In December 2015, SpaceX began using an upgraded Falcon 9 design that uses supercooled liquid oxygen at minus 340 degrees, 40 degrees colder than what is typically used. The lower temperature makes the oxygen denser, which improves engine thrust.
But the helium was even colder. As the carbon and aluminum cool, they shrink at different rates, opening gaps into which liquid oxygen could flow. In addition, the helium may have been below the temperature at which oxygen freezes, and some of the trapped oxygen may have become solid.
“Really surprising problem that’s never been encountered before in the history of rocketry,” Elon Musk, the CEO of SpaceX, said in an interview on CNBC in November.
Both carbon and aluminum can burn, and with oxygen sandwiched in between, all of the ingredients for a conflagration were present. Friction or the breaking of fibers could have provided the energy for ignition, the company said.
Tests at SpaceX’s facilities in Hawthorne, California, and McGregor, Texas, supported that conclusion, the company said.
Last week, Iridium officials said the satellites had been fueled, pressurized, stacked and encapsulated in the rocket’s nose cone, which will be lifted onto the rocket in anticipation of the launch; however, Iridium CEO Matt Desch has said the spacecraft won’t be on top of the rocket during the static fire test.