Starship — the huge spacecraft that Elon Musk says will one day take people to Mars — failed during its latest test flight on Thursday when its upper stage exploded in space, raining debris and disrupting air traffic at airports from Florida to Pennsylvania.

It was the second consecutive test flight of the most powerful rocket ever built where the upper-stage spacecraft malfunctioned. It started spinning out of control after several engines went out and then lost contact with mission control.

Photographs and videos posted on the social media site X by users saying they were along the Florida coast showed the spacecraft breaking up. The falling debris disrupted flights at airports in Miami, Orlando, Palm Beach and Fort Lauderdale, and as far away as Philadelphia International Airport.

The Starship rocket system is the largest ever built. At 403 feet tall, it is nearly 100 feet taller than the Statue of Liberty atop its pedestal.

It has the most engines ever in a rocket booster: The Super Heavy booster is powered by 33 of SpaceX’s Raptor engines. As those engines lift Starship off the launchpad, they will generate 16 million pounds of thrust at full throttle.

The upper part, also called Starship or Ship for short, looks like a shiny rocket from science fiction movies of the 1950s, is made of stainless steel with large fins. This is the upper stage that will head toward orbit, and ultimately could carry people to the moon or even Mars.

The rocket lifted off a little after 6:30 p.m. Eastern time on Thursday from the SpaceX site known as Starbase at the southern tip of Texas near the city of Brownsville.

Starship’s mammoth booster again successfully returned to the launchpad, just as it had during the previous test flight. In the last half minute before the upper-stage engines were to shut off, several of them malfunctioned. Video from the rocket showed a tumbling view of Earth and space until it cut off.

In an update posted on SpaceX’s website, the company said, “Prior to the end of the ascent burn, an energetic event in the aft portion of Starship resulted in the loss of several Raptor engines. This in turn led to a loss of attitude control and ultimately a loss of communications with Starship.”

Communications with the spacecraft ended 9 minutes and 30 seconds after liftoff, SpaceX said.

The company said it immediately coordinated with safety officials “to implement pre-planned contingency responses.”

Shortly after the spacecraft broke up, the Federal Aviation Administration issued ground stoppage orders for the airports. It cited “space launch debris” as the reasons in each of the cases.

Some airlines said the effects of the incident had been limited on Thursday evening.

“We had some minor impacts on our South Florida operation, but things are getting back on track,” Southwest Airlines said in a statement.

The F.A.A. said it was grounding Starship until SpaceX completed an investigation of Thursday’s incident.

It was the eighth test flight for the rocket. During the previous test flight in January, the first part of the launch proceeded smoothly, with all 33 engines of the booster lifting the rocket toward space. The booster also separated properly, and the six engines of the second-stage spacecraft ignited, pushing it upward.

But something went wrong, and air traffic over the Caribbean had to be diverted and delayed around falling debris, some of which landed on the Turks and Caicos Islands.

In the first six tests, SpaceX demonstrated that the rocket’s basic design works and that the Starship can return to Earth almost intact. Over the coming year, SpaceX is looking to improve “more or less” to “reliably” and prove out other capabilities. The company is likely to receive approval from the F.A.A. for up to 25 flights this year.

The F.A.A. is trying to work around conflicts of interest with Mr. Musk and SpaceX.

The agency last month hired three SpaceX employees to work temporarily to help the agency upgrade the agency’s air traffic control system and other technology.

But ethics letters sent to the three employees assert that they “will not receive access to systems” at the Office of Commercial Space Transportation, which is the part of the F.A.A. that regulates SpaceX.

The demise of the previous Starship was likely caused by stronger-than-expected shaking when the rocket vibrated like an organ pipe, SpaceX’s investigation concluded. The vibrations caused leaks of propellant that ignited.

According to the company’s analysis, the self-destruct system blew up the rocket a few minutes later.

To address the problems during the seventh flight, the company said that feed lines carrying propellant to the engines were changed to reduce the oscillations. SpaceX also altered the propellant temperatures and thrust levels of the engines to avoid a repeat of the leaks.

For the rocket on this flight, SpaceX also added more vents to the attic section, and a system to purge the area of propellants in order to reduce the chance of fires.

The F.A.A. oversaw SpaceX’s investigation, and it issued a launch license last week for the eighth flight.

Scott Ferguson, 43, a neuroscientist and amateur astronomer who was eager observe the flight, positioned himself with a telescope in a parking lot near his home in Sarasota, Fla.

At about 6:40 p.m., he saw a large cloud suddenly appear through his telescope. A few seconds later, he said he saw one large piece of the craft’s body “surrounded by metallic debris that looked like stars twinkling all around it.”

A couple minutes later, Mr. Ferguson said he heard a loud bang that reminded him of the sonic booms that he heard growing up in Titusville, Fla., near NASA’s Kennedy Space Center. Additional booms followed about 10 minutes later.

Starship is not the only rocket flown by SpaceX that has had recent glitches. Some of the Falcon 9 rockets it launches from Florida and California every few days have also had problems.

During a launch in February, a Falcon 9 upper stage failed to execute the usual engine burn to ensure that the rocket’s remains would splash down in the ocean. Instead, it remained in orbit. Air resistance caused it to fall gradually, and the stage re-entered the atmosphere 18 days later over Europe. No one was hurt or injured, but pieces of the rocket appear to have landed in Poland.

SpaceX encountered another problem on Sunday night when a Falcon 9 booster successfully landed on a barge in the Atlantic Ocean but then fell over.

The company reported that “an off-nominal fire in the aft end of the rocket damaged one of the booster’s landing legs which resulted in it tipping over.”

NASA is planning to use a version of Starship to take astronauts from lunar orbit to the surface of the moon during its Artemis III mission, currently scheduled for 2027.

But that mission could be delayed, or even canceled, if the Trump administration revamps the moon program or shifts its attention to Mars.

SpaceX will need to demonstrate high reliability of Starship before a flight with people on board takes place.

Hank Sanders, Niraj Chokshi and Eric Lipton contributed reporting.

At a confirmation hearing for Dr. Marty Makary on Thursday, senators focused heavily on the safety of the abortion pill, with Republican lawmakers urging him to restrict access and Democratic lawmakers demanding that he maintain its current availability.

Dr. Makary, President Trump’s nominee to lead the Food and Drug Administration, signaled that he shared Republicans’ concerns about the current policy, issued during the Biden administration, which expanded access by allowing people to obtain the pills without an in-person medical appointment.

Several Democrats pointed to volumes of studies showing that the drugs are safe. Dr. Makary told members of the Senate health committee, which held the hearing, that he would review the pill’s safety and the policy at issue.

He said he would “take a solid, hard look at the data and to meet with the professional career scientists who have reviewed the data at the F.D.A. and to build an expert coalition to review the ongoing data, which is required to be collected.”

The hearing also touched on vaccines, with several lawmakers, including the committee chairman, Senator Bill Cassidy, Republican of Louisiana, questioning why an advisory committee meeting on next year’s flu vaccine had been canceled in recent weeks and asking whether it would be held later. He and others stressed that the flu panel met annually, and some reminded Dr. Makary that Robert F. Kennedy Jr., who oversees the F.D.A. as health secretary, had pledged transparency in agency decision-making.

Senator Patty Murray, Democrat of Washington, called the cancellation “unprecedented and dangerous” after decades of annual meetings.

Dr. Makary repeatedly reminded senators that he was not responsible for scrapping the meeting. He also suggested there was a need for a broader review of the role of vaccine committees that convene experts to advise the F.D.A. He shot back at criticism, saying there is a “huge difference” between “requiring every 12-year-old girl to get an eighth Covid booster” and “rubber stamping” the vaccine chosen by a global health panel that had targeted dominant influenza strains.

He offered no details about any school or entity that requires children to have annual Covid boosters.

He also was questioned about the measles vaccine in light of the current outbreak in Texas, where one child has died and 22 people were hospitalized.

“Vaccines save lives,” Dr. Makary said. “I do believe that any child who dies of a vaccine-preventable illness is a tragedy in the modern era.”

But he did not take the bait lobbed by Senator John Hickenlooper, Democrat of Colorado, who criticized Mr. Kennedy’s endorsement of vitamin A and cod liver oil as remedies for measles. Dr. Makary responded by saying that supplements can improve conditions like malnutrition, which is associated with poor outcomes in measles outbreaks.

Lawmakers also warned about staff cuts and hiring freezes the Trump administration has ordered and how they could affect workers who inspect the safety of the food supply, and urged Dr. Makary to review the layoffs among those staff members whose salaries are backed by industry fees.

They also touched on work related to chemicals like dyes in the food supply, an area Dr. Makary agreed to study, invoking European products with fewer additives as an area for review.

Among other issues raised during the hearing, the vexing problem of illegal vape products from China with unknown ingredients was stressed by Senator Ashley Moody, Republican of Florida.

The vapes tend to have high levels of nicotine, advertise thousands of puffs and come in flavors like strawberry lemonade that are appealing to adolescents.

Ms. Moody said it was concerning that the products were banned within China.

“Whoever comes in as the head of F.D.A., this is one of your problems you have to address immediately,” said Ms. Moody, who was previously Florida’s attorney general.

Blocking the flow of the unauthorized vapes has been a priority for major tobacco companies that have followed F.D.A. rules and marketed vapes in tobacco or menthol flavors in the United States. It’s a priority public health groups also share. Dr. Makary said he would address the problem with the F.D.A.’s law enforcement division and the Justice Department.

Throughout the hearing, several senators returned to the abortion pill and the F.D.A.’s oversight of policy changes during the lengthy history of medication abortion over more than two decades.

Mifepristone — part of the standard two-drug medication regimen now used in nearly two-thirds of abortions — has become a focal point of anti-abortion efforts since the Supreme Court overturned the national right to abortion in 2022.

In a lawsuit filed against the F.D.A. and other efforts, abortion opponents have demanded that the agency either withdraw approval for mifepristone or roll back regulations to prevent abortion pills from being prescribed by telemedicine and mailed to patients.

The Biden administration waived the in-person dispensing requirement in 2021. Senator Maggie Hassan, Democrat of New Hampshire, said that she was concerned that Dr. Makary would “unilaterally overrule the data that currently exists for political purposes and for political reasons.”

Dr. Makary repeated that he had no preconceived notions and would examine the data. “I wish you were hedging a little bit less today,” Ms. Hassan shot back.

Mifepristone, which blocks progesterone, a hormone necessary for pregnancy to develop, has long been regulated by the F.D.A. under an especially strict program that applies to only a small number of drugs.

For years after its approval in 2000, mifepristone could be prescribed only by a doctor and patients were required to attend three in-person doctor visits to obtain and take the medication. In 2016 and 2021, based on updated scientific evidence, the agency made several changes, including that nurse practitioners and some other health care providers could prescribe mifepristone and that patients did not have to pick up the medication in person.

Senator Josh Hawley, Republican of Missouri, argued that the policy change to drop the requirement for in-person appointments was made in anticipation of the Supreme Court decision that overturned Roe v. Wade.

Reproductive health experts and organizations, however, had long argued that the requirement was unnecessary for safety and noted that the F.D.A. had already allowed women to take the medication at home without being supervised by a doctor. The Covid pandemic increased the importance of allowing people to obtain the pill by mail because many patients were not able to visit clinics or abortion providers.

Pressed further by Mr. Hawley, Dr. Makary signaled that he shared the concerns of some abortion opponents and said that he knew doctors who preferred to give the drug in their office: “I think their concern there is that if this drug is in the wrong hands, it could be used for coercion,” he said.

Mr. Cassidy closed the hearing with a direct request: to change the policy back to what it was in the first Trump administration and require an in-person visit.

The F.D.A. has a staff of about 18,000 and a budget of about $7.2 billion. The agency has vast regulatory authority over products that include prescription and over-the-counter drugs, medical devices, tobacco and about 80 percent of the food supply. It also regulates artificial intelligence software used to scan medical images, an area where the agency has been dismissed as too permissive in its approvals.

If confirmed, Dr. Makary would first encounter tensions among staff members, who have been whipsawed by the Trump administration’s aggressive measures to reshape the federal bureaucracy in recent weeks.

The staff endured an initial round of about 700 layoffs, decimating some product-review teams that ensure the safety of medical devices such as surgical robots and systems that deliver insulin to people with diabetes. Those firings were followed by some job reinstatements, though many of those in the tobacco division who review the safety of new products and lost their positions, were not called back.

Asked about the layoffs, Dr. Makary said he supported efforts to increase efficiency and that he would review recent personnel decisions.

Pam Belluck contributed reporting.