NASA to Require Uncrewed Starliner Test Flight Following 2024 Astronaut Stranding

Key facts

On June 5, 2024, Boeing launched its CST-100 Starliner on its first piloted test flight, designated the Crew Flight Test (CFT), from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida. Aboard were veteran NASA astronauts Barry "Butch" Wilmore and Sunita "Suni" Williams. The goal was to demonstrate the capsule's launch, rendezvous, docking, and landing capabilities with crew on board.

Trouble arose during the approach to the International Space Station on June 6, 2024. Telemetry indicated multiple helium leaks within the spacecraft's service module propulsion manifolds, and 5 of the spacecraft’s 28 Reaction Control System (RCS) thrusters experienced unexpected shutdowns. Although crew members and controllers safely docked with the orbital station, the cause of the failures remained under investigation.

What was intended as an eight-day mission stretched into months. Engineers from NASA and Boeing conducted diagnostic testing on thruster pods at NASA’s White Sands Test Facility in New Mexico. Tests indicated that extreme heating caused Teflon seals inside the thrusters to expand, restricting propellant flow and reducing thruster performance.

Due to uncertainties surrounding thruster behavior during the critical deorbit burn, NASA Administrator Bill Nelson announced on August 24, 2024, that returning Wilmore and Williams on Starliner presented unacceptable safety risks. NASA decided to return the spacecraft empty while reassigning the astronauts to return in early 2025 on a SpaceX Crew Dragon capsule.

Starliner undocked automatically on September 6, 2024, and landed safely under parachutes at White Sands Space Harbor in New Mexico the following day. Post-flight telemetry analysis led NASA to conclude that a single uncrewed landing was insufficient to clear the spacecraft for human flight. As reported by CBS News, NASA determined that Boeing must complete another uncrewed test flight to verify that redesigned thruster housings, improved insulation, and updated software eliminate the defects.

Why it matters

The requirement for an extra uncrewed test flight carries major operational, financial, and strategic consequences for NASA and the U.S. aerospace sector.

At the center of NASA’s Commercial Crew Program is the policy of dissimilar redundancy. By contracting two independent launch providers—SpaceX and Boeing—the agency aimed to guarantee uninterrupted access to the International Space Station. If one vehicle were grounded due to hardware failure, the secondary provider would maintain human access to orbit. Currently, NASA relies almost entirely on SpaceX’s Crew Dragon capsule alongside Russia’s Soyuz spacecraft, leaving the U.S. commercial crew architecture without its intended redundancy.

Financially, the additional test flight creates significant losses for Boeing. Under the terms of the fixed-price Commercial Crew contract, Boeing must absorb all development overruns and flight costs. Prior to this requirement, Boeing had already recorded over $1.5 billion in cumulative pre-tax losses on Starliner. Conducting another test flight requires securing a United Launch Alliance Atlas V rocket, assembling capsule hardware, and funding ground operations without additional NASA compensation.

Time constraints also press against the program. The International Space Station is slated for retirement around 2030. Boeing is contracted for six operational crew rotation flights, designated Starliner-1 through Starliner-6. Continual schedule slippage shrinks the remaining window for Boeing to fulfill these contractual obligations before the station is decommissioned.

NASA established the Commercial Crew Program following the retirement of the Space Shuttle fleet in 2011. For nine years, the United States relied on Russian Soyuz spacecraft to carry astronauts to the International Space Station, paying seats costing upwards of $80 million each.

In September 2014, NASA awarded fixed-price contracts under the Commercial Crew Transportation Capability program. Boeing received $4.2 billion for Starliner, while SpaceX received $2.6 billion for Crew Dragon. Contracts targeted operational flight certification by 2017, but both companies faced technical delays.

SpaceX completed its uncrewed demonstration flight in March 2019 and its crewed test flight in May 2020. NASA certified Crew Dragon for operational missions in November 2020. Since then, SpaceX has completed over a dozen crewed missions to orbit.

Boeing’s path faced repeated setbacks. Its first uncrewed test, Orbital Flight Test 1 in December 2019, suffered software timer errors that prevented it from reaching the space station. In August 2021, Orbital Flight Test 2 was postponed on the launchpad when moisture corroded 13 propulsion valves. Boeing successfully completed Orbital Flight Test 2 in May 2022, docking with the space station despite minor thruster drops. Subsequent delays in June 2023 were caused by flammable wiring tape and parachute harness structural concerns, delaying the crewed launch to June 2024.

Reaction

Official responses highlight differing perspectives on safety compliance and operational recovery.

NASA leadership framed the uncrewed test requirement as a necessary measure to protect astronaut safety. NASA Administrator Bill Nelson emphasized that human spaceflight carries inherent risk and that safety standards cannot be compromised when validating propulsion hardware. Commercial Crew Program management noted that verifying corrections on an uncrewed vehicle prevents placing crew members in harm's way.

Boeing expressed its commitment to addressing technical deficiencies and completing Starliner certification. Executives noted that engineering teams are actively redesigning thruster thermal insulation and refining flight control software. Boeing reiterated its intent to fulfill its contractual obligation to provide crew transport services to NASA.

Industry analysts and congressional leaders supported NASA's safety focus while highlighting the risks of relying on a single commercial vendor. Congressional oversight committees reaffirmed the necessity of maintaining dual-provider capability to avoid single-point vulnerabilities in U.S. space transportation.

What we don't know yet

Key details surrounding the upcoming uncrewed flight test remain unconfirmed.

First, NASA and Boeing have not published a firm launch date for the uncrewed test mission. The timeline depends on completing thruster redesigns, conducting ground-test burns, and passing formal safety reviews.

Second, the overall financial impact on Boeing remains unstated. Additional charges will depend on procurement costs for the launch vehicle and ongoing operational engineering support.

Third, questions remain regarding rocket availability. United Launch Alliance is phasing out the Atlas V rocket in favor of Vulcan Centaur. ULA previously reserved a fixed allotment of Atlas V boosters for Starliner missions; it is not yet public whether this test will consume a booster originally assigned to an operational mission.

Finally, NASA has not specified whether a successful uncrewed flight will immediately lead to Starliner operational certification or if further evaluation flights will be required.

What to watch

To monitor progress on the Starliner program, observers should track several key milestones:

This report incorporates information originally reported by CBS News.