NASA

Artemis 2 is a precursor to the US space agency’s planned astronaut moon landing with Artemis III scheduled for 2028.

NASA chief Jared Isaacman says Artemis 2 – the first crewed flyby mission to the moon in more than 50 years – will not launch next month because of technical problems.

Workers detected an issue with helium flow to the massive Space Launch System (SLS) rocket that will “take the March launch window out of consideration”, Issacman said in a post on social media Saturday.

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Solid helium flow is essential for purging the rocket’s engines and pressurising its fuel tanks.

“I understand people are disappointed by this development. That disappointment is felt most by the team at NASA who have been working tirelessly to prepare for this great endeavor,” Isaacman said.

NASA’s next opportunity for the launch would be at the beginning or end of April.

The US space agency hopes to put humans back on the moon as China forges ahead with a rival effort that is targeting 2030 at the latest for its first crewed mission.

China’s uncrewed Chang’e 7 mission is expected to be launched in 2026 for an exploration of the moon’s south pole, and testing of its crewed spacecraft Mengzhou is also set to go ahead this year.

Multiple postponements

NASA surprised many late last year when it said Artemis 2 could happen as soon as February – an acceleration explained by the administration of US President Donald Trump’s wish to beat China to the punch.

But the programme has been plagued by delays. The uncrewed Artemis 1 mission took place in November 2022 after multiple postponements and two failed launch attempts.

Then, technical problems in early February – which included a liquid hydrogen leak – cut short a so-called wet dress rehearsal for the Artemis 2 launch. That was finally completed earlier this week.

The wet dress rehearsal was conducted under real conditions – with full rocket tanks and technical checks – at Cape Canaveral in Florida, with engineers practising the manoeuvres needed to carry out an actual launch.

The space agency revealed the latest technical problem just one day after targeting March 6 for the launch of the Artemis 2 mission.

The towering SLS rocket and Orion spacecraft will be rolled back into the Vehicle Assembly Building at the Kennedy Space Center in Florida to investigate the technical issues and make any necessary repairs, Isaacman said. He said a bad filter, valve, or connection plate could be to blame for the stalled helium flow.

Isaacman added that a complete briefing will follow in the coming days.

The goal of the Artemis 2 mission, a 10-day flight around the moon and back, is to “explore the Moon for scientific discovery, economic benefits, and to build the foundation for the first crewed missions to Mars”, according to NASA.

The planned Artemis 2 crew includes three US astronauts – Reid Wiseman, Victor Glover, and Christina Koch – and Canadian astronaut Jeremy Hansen. The mission is poised to be the farthest human flight into space ever, and the first crewed moon mission since the US Apollo programme more than half a century ago.

Artemis 2 is a precursor to NASA’s planned astronaut moon landing with Artemis 3, which is scheduled for 2028.

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For NASA astronauts, experiencing zero-gravity conditions prior to mission launch is a necessary, if absurdly fun and enviable, part of training and familiarization. The ability to provide a microgravity environment here on Earth is also important for a number of scientific research reasons, and especially for spaceflight applications. For the better part of a century, access into this environment has been provided by specialized fixed-wing aircraft that fly parabolic arcs – collectively, and evocatively, dubbed “The Vomit Comet” for the physical side effect of weightlessness they tend to induce. While a single private company has handled these zero-G flights for NASA for years, a new contract solicitation shows the agency is once again inviting competitors to bid for the work, with the possibility of providing new solutions for a decades-old requirement.

What It Feels Like to Fly in NASA’s Crazy Zero-Gravity Plane

The solicitation, posted by NASA’s Armstrong Flight Research Center in support of the Flight Opportunities Program, seeks information from industry on a variety of capabilities to deliver reduced-gravity and microgravity environments, specifically for testing new technologies and conducting research. The document emphasizes that the method of achieving the effect of weightlessness can look different than it has in the past.

“Respondents are encouraged to submit capabilities statements with innovative approaches to delivering Parabolic Flight Services,” the solicitation states. “This may include the use of aircraft platforms not traditionally used for parabolic flight services (e.g., business jets, experimental aircraft, supersonics, autonomous systems). NASA is interested in flexible, scalable, and novel operational concepts with the potential to help NASA expand access to reduced-gravity environments and accelerate space technology readiness.”

Starting in the late 2000s, NASA has used the same commercial provider for both human zero-gravity familiarization training and technological experiments. That’s the Florida-based Zero-G corporation, which offers parabolic flights on a retrofitted Boeing 727-200 dubbed ‘G-Force One.’ On the standard 90-minute flight the company offers, the aircraft will hit an altitude of 24,000 feet before beginning a steep climb at a 45-degree angle into a parabola that peaks around 32,000 feet. During the maneuver, passengers pull 1.8 Gs, according to the company; near the crest of the arc, the low-gravity phase begins, creating roughly half a minute of weightlessness. 

G-Force One completes 15 parabola maneuvers in a single flight. 

Total Weightless! What Happened on my Zero Gravity Flight?

While Zero-G offers separate rates for research flights, individuals ages eight and up can have the full experience for $8,900 per person, or $295,000 for the full 28-seat plane, plus a dedicated photographer. This option also allows for television and movie filming opportunities; Zero-G has a staff production director to support film production.

NASA granted Zero-G a five-year Indefinite Delivery, Indefinite-Quantity contract worth $7.5 million in 2021, marking a continuing partnership between the two entities.

“From 2008 to 2015, NASA and Zero-G had a previous contract under which the company flew microgravity missions in Texas,” Space.com noted at the time. “Though, unlike this new contract, those flights were conducted under ‘public use’ government regulations rather than under FAA regulations.”

Zero-G says it remains the only FAA-approved provider of parabolic flights in the United States.

Vomit Comet history began with a Convair C-131 Samaritan, a militarized version of a twin-engine passenger aircraft originally used by the Air Force for VIP transport and medical evacuation (MEDEVAC) missions. The service began using the planes to simulate zero gravity in 1957, and NASA took over the work in 1973.

ZERO “G”

Eventually, a Boeing KC-135 Stratotanker, a type that first went into USAF service in 1957 and variants of which are still used for aerial refueling today, became the new Vomit Comet. One of the KC-135As that served in this role reportedly executed more than 58,000 parabolas and played a key role in filming for the blockbuster “Apollo 13.”

“Then-lead test director John Yaniec said KC-135A was still going strong when it was retired in 2004, but its unique role made it ‘increasingly difficult and expensive to maintain,’” Space.com reported in 2017.

Zero G in Airplane

A C-9B (DC-9) that NASA acquired subsequently took over the role for about a decade before it too was put out to pasture. Vomit Comet duties were then fully turned over to the private sector.

While Zero-G had flown more than 2,300 research parabola flights for NASA as of 2025 – and offered a taste of the final frontier to ground-based Space Force Guardians, among others – the benefits of expanding the pool of providers are self-evident. Zero-G temporarily shuttered operations in 2020 during the worst of the COVID-19 pandemic and, in 2022, had to take G-Force One out of service for a period due to unspecified equipment issues. (Air Force Academy cadets who were expecting to experience weightlessness at the conclusion of a summer program went SCUBA diving instead). With commercial 727s increasingly rare, it’s likely that maintaining G-Force One and sourcing replacement parts is becoming more costly and difficult. 

It’s not certain, though, what competitors exist for Zero-G’s offering. While the solicitation mentions autonomous systems as one possibility for research flights, it also notes that “NASA expects some (if not most) payloads to have a human-tended requirement.”

Eligible contractors must be capable of providing two or more parabolic maneuver types per flight to simulate a range of gravity conditions, including microgravity, and Lunar and Martian gravity, among others. Their platforms need to be capable of sustaining each gravity level for at least 10 seconds, though 30 seconds or better is preferred.

“In some cases, the objective may be to maximize the duration of low gravity exposure with less emphasis on accuracy and stability. This would be most likely with a non-critical payload where the objective is to give the flight participant a microgravity experience,” the solicitation notes. “In other cases, the accuracy and stability of the gravity level may be critical and duration less important.”

While Zero-G appears to have cornered the U.S. parabolic flight market for now, Europe has several different options. The French Space Agency’s Novespace research subsidiary operates parabolic flights using the Airbus A310 for researchers and private enthusiasts. In the United Kingdom, the startup Blue Abyss offers zero-G flights with a modified Boeing 757.

This is how zero-g flights actually work

Blue Abyss now appears to be positioning itself as a competitor in the space. Last year, it broke ground on an ambitious space training facility in Brook Park, Ohio, partnering with NASA on a project it says will ultimately offer parabolic flight capabilities.

Using disparate performing aircraft and even unmanned systems for tailored low-gravity missions could open new frontiers in providing these environments here on Earth. For instance, higher-performing aircraft could potentially offer longer sustained zero-G intervals, while unmanned systems could take this even further, especially for non-human payloads. Different platforms offering different services could also allow for cheaper and faster access to low-gravity within Earth’s atmosphere.

Case in point, drone-based microgravity experiments are also underway in Europe. In 2023, the British company Gravitilab used a specially adapted quadcopter to simulate weightlessness conditions for its payload in a 2,000-foot drop.

The achievement will “open the world of microgravity research to a new market,” the company announced at the time.

NASA’s market research solicitation will remain open until March 2.

Contact the editor: Tyler@twz.com

Feb. 3 (UPI) — NASA early Tuesday announced it was pushing the launch date of its Artemis II mission to March, after engineers encountered a liquid hydrogen leak during a critical prelaunch test.

“With the conclusion of the wet dress rehearsal today, we are moving off the February launch window and targeting March for the earliest possible launch of Artemis II,” NASA Administrator Jared Isaacman said in a statement.

The announcement followed the completion of a two-day test called a wet dress rehearsal of its planned lunar flyby at Launch Complex 39B at NASA’s Kennedy Space Center in Florida, which involved Mission Control at the Johnson Space Center in Houston.

NASA had initially aimed to launch Artemis II in a Feb. 8-11 window.

Moving the mission’s launch window will give teams time to review data and conduct a second wet dress rehearsal, NASA said in a separate statement.

“Moving off a February launch window also means the Artemis II astronauts will be released from quarantine, which they entered in Houston on Jan. 21,” it said.

NASA began the 49-hour countdown of the wet dress rehearsal at 8:13 p.m. EST Saturday. The test included the loading of cryogenic propellant into the Space Launch System tanks, sending a team out to the launch pad to close out the Orion spacecraft and safely draining the rocket, among other maneuvers.

Officials said that a liquid hydrogen leak occurred during tanking, and that engineers spent several hours troubleshooting the issue.

By allowing the interface to warm up so seals could reseat and by adjusting propellant flow, teams were able to successfully fill all tanks in both the core stage and interim cryogenic propulsion stage, they said.

The countdown reached about T-5 minutes when a spike in the liquid hydrogen leak rate automatically stopped the countdown sequencer.

“With more than three years between SLS launches, we fully anticipated encountering challenges,” Isaacman said. “That is precisely why we conduct a wet dress rehearsal. These tests are designed to surface issues before flight and set up launch day with the highest probability of success.”

“This is just the beginning,” Isaacman added.

The Artemis I mission in 2022 was a successful uncrewed launch of NASA’s new rocket and spacecraft system. The mission flew around the moon.

The Artemis II seeks to do the same mission but with astronauts. It will carry the first crewed lunar flyby in more than 50 years.

NASA’s Space Launch System rocket, with the Orion spacecraft perched on top, stands on Complex 39B early Sunday at the Kennedy Space Center in Florida as a wet dress rehearsal for the Artemis II mission around the moon gets started. The mission will launch no earlier than February 8. Photo by Joe Marino/UPI | License Photo

Feb. 1 (UPI) — After adjusting its timeline for the last remaining tests of the Artemis II space launch system and Orion capsule because of freezing cold temperatures in Florida, NASA is now pressing ahead in preparation for its launch to the moon.

NASA had planned to start the fueling phase of the wet dress rehearsal for the rocket’s launch cadence on Saturday night, but a blast of Arctic air reached all the way down to Kennedy Space Center in Florida making it too cold to load propellants into the ship’s fuel tanks.

As a result, the fueling tests were pushed back to Monday — and launch will now happen no earlier than Feb. 8 — as the agency held off on powering up the SLS rocket’s core stage until Sunday morning.

“NASA continues to press ahead through the countdown for the Artemis II wet dress rehearsal,” NASA said in a statement. “Teams monitored all systems throughout the overnight hours [Saturday] during cold temperatures and high winds.”

The wet dress rehearsal is a test of the full launch team and the series of complex steps involved in a space launch, which includes engineers in Florida, at Mission Control at Johnson Space Center in Houston and at other NASA facilities.

The tanking phase of the wet dress rehearsal involves loading more than 700,000 gallons of liquid oxygen and liquid hydrogen, as will happen before the actual launch.

The test involves filling, topping off and replenishing the tanks over a series of loading milestones.

Engineers also will start preparing to charge the Orion space capsule’s flight batteries and the core stage battery, in addition finishing preparations of the umbilical arms and a walk down at the launch pad, NASA said.

Tanking operations require an overall outdoor temperature above 41 degrees, and cannot dip below 40 for more than 30 consecutive minutes, during both the rehearsal and actual launch.

The full wet dress rehearsal is a complete countdown simulation — the wet dress countdown started Sunday at minus-39 hours and 30 minutes — and will end with a simulated launch window on Monday around 9:00 p.m. EST, NASA said.

Artemis II’s launch window is currently set for Feb. 8 to Feb. 11, but NASA has previously said that if the rocket is not ready to launch next week that additional launch windows in March and April have been identified.

Jan. 30 (UPI) — Frigid temperatures have delayed NASA’s preparations for its wet dress rehearsal for the Artemis II launch, the space agency announced Friday.

NASA was expected to begin the tanking operation Saturday night in preparation for a possible Feb. 6 or Feb. 7 launch date, but those “are no longer viable opportunities,” a release said.

The agency now expects to set Monday as the tanking day with an earliest possible launch set for Feb. 8 at the Kennedy Space Center in Cape Canaveral, Fla.

Tanking operations involve loading propellants into a fuel tank near the launch pad. The outdoor temperature plays a crucial role in that process — it can’t be below 40 degrees Fahrenheit for more than 30 consecutive minutes. The overall average temperature must be above 41 degrees for the rehearsal and launch, WESH-TV in Orlando, Fla., reported.

AccuWeather forecasters said temperatures were expected to plummet this weekend to levels not seen since 1966 in some areas. Temperatures between 20 degrees to 30 degrees were expected Sunday morning in Cape Canaveral.

“Adjusting the timeline for the rest will position NASA for success during the rehearsal, as the expected weather this weekend would violate launch conditions,” a release from NASA said.

In the meantime, the Artemis II crew members are expected to stay in quarantine in Houston. The crew includes Reid Wiseman, commander; Victor Glover, pilot; Christina Koch, mission specialist; and the Canadian Space Agency’s Jeremy Hansen, mission specialist.

Artemis II is NASA’s first crewed mission aboard its deep space rocket, the Space Launch System, and Orion spacecraft. It’s the second flight of the SLS and the first crewed mission near the moon since 1972.

Over 10 days, Artemis II will travel around the moon and back to Earth as the crew tests whether the spacecraft operates as it should in deep space. The long-term goal of the Artemis program is reestablish a human presence on the moon in preparation for the ultimate aim of putting a human on Mars.

NASA has shared a live stream of the launch pad on YouTube as it prepares for the wet dress rehearsal launch.

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One of NASA’s high-flying WB-57F research aircraft went skidding down the runway on its belly at Ellington Airport in Houston, Texas, earlier today.

The incident occurred at around 11:30 AM local time, according to KHOU, a local CBS affiliate in Houston. KHOU has shared video footage showing the two-seat WB-57F spraying sparks and smoke after making contact with the runway. Additional footage shows the pilot exiting the plane with the help of first responders on the ground.

Plane appears to land without gears at Ellington Airport in Houston

NASA plane makes belly landing at Ellington Field, video shows

“Today, a mechanical issue with one of NASA’s WB-57s resulted in a gear-up landing at Ellington Field. Response to the incident is ongoing, and all crew are safe at this time,” NASA’s official account on X wrote in response to KHOU‘s report. “As with any incident, a thorough investigation will be conducted by NASA into the cause. NASA will transparently update the public as we gather more information.”

Today, a mechanical issue with one of NASA’s WB-57s resulted in a gear-up landing at Ellington Field. Response to the incident is ongoing, and all crew are safe at this time. As with any incident, a thorough investigation will be conducted by NASA into the cause. NASA will…

— NASA (@NASA) January 27, 2026

KHOU also reported that Ellington’s runway 17R–35L was closed as efforts were made to move the stricken WB-57F.

All three of NASA’s WB-57Fs are based at the Johnson Space Center, also located in Houston. The aircraft are well known for their high-altitude capabilities, and can fly as high as 63,000 feet depending on how they are configured. They can carry different sensors and other systems in modular payload bays under the fuselage, as well as in their noses and underwing pods. Though roughly similar in some respects, the WB-57F should not be confused with the U.S. Air Force’s higher-flying U-2s. NASA also operates a pair of ER-2 aircraft, which are modified U-2s.

The WB-57Fs, originally developed for the U.S. Air Force during the Cold War as high-flying intelligence-gathering platforms, are now used for various scientific research purposes. The jets have also been used to support various U.S. military operational and test and evaluation-type missions. One of them was notably called upon to help in the response to weeks of still unexplained drone incursions over Langley Air Force Base in Virginia in December 2023, which TWZ was first to report. Many aerial videos of space launches that we see are taken by the WB-57Fs, as well.

Overall, NASA’s WB-57Fs are the definition of an extremely low-density, high-demand asset, and what long-term impacts today’s belly landing may have on the future of the fleet remain be seen.

Update: 4:20 PM EST —

The Federal Aviation Administration (FAA) has now provided TWZ with the following statement:

“A Martin WB-57 landed with its gear up at Ellington Airport in Houston around 11:25 a.m. local time on Tuesday, Jan. 27. Two people were on board. The FAA will investigate.”

Howard Altman contributed to this story.

Contact the author: joe@twz.com

Jan. 28 (UPI) — A NASA research jet performed a gear-up landing at Houston’s Joint Reserve Base Ellington after suffering a “mechanical issue,” according to NASA officials.

Uncorroborated video of the Tuesday landing posted online shows the plane, a WB-57 research aircraft, coming in low toward the runway, touching down with the belly of its fuselage.

Sparks, fire and smoke spew from the back of the plane as it comes to a stop, the video shows.

NASA Press Secretary Bethany Stevens said in a statement that the gear-up landing was the result of an unspecified “mechanical issue.”

“Response to the incident is ongoing, and all crew are safe at this time,” she said.

“As with any incident, a thorough investigation will be conducted by NASA into the cause. NASA will transparently update the public as we gather more information.”

The incident occurred at about 11:30 a.m. CST Tuesday on Runway 17R-35L, according to Houston Airports, the Texas city’s Department of Aviation.

The WB-57 high-altitude research plane is a mid-wing, long-range aircraft based near the NASA Johnson Space Center in Houston.

According to NASA, three of the jets operate out of Ellington Field, and can fly in excess of 63,000 feet above sea level. It can also fly for about 6 1/2 hours with a range of about 2,500 miles.

A pilot and a sensor equipment operator generally crew the aircraft during flights.