Facts summary and sources
NASA X-43A: speed field: Mach 9.6 (Reported flight result). First flight attempt: 2001 (first attempt). First launch attempt: June 2, 2001 (unsuccessful); first successful scramjet flight: March 27, 2004.
This is a secondary compilation. A source-check date applies only to the listed claim, not to the whole page or its translation. A page update is not a source check.
Sources and check records
- NASA: X-43A — NASA reports Mach 9.6 and approximately 7,000 mph on the final X-43A flight, an air-breathing aircraft record. [Reported flight result] · Event date: 2004-11-16 · Source checked for this claim: 2026-09-28
- NASA: X-43A — First launch attempt: June 2, 2001 (unsuccessful); first successful scramjet flight: March 27, 2004. [Launch attempt and successful-flight dates] · Event date: 2001-06-02 · Source checked for this claim: 2026-09-28
- Wikipedia reference · Source-check date not recorded
✈️ Full Specifications
| Designation | X-43A |
| Manufacturer | NASA / Boeing / ATK GASL |
| Country | 🇺🇸 United States |
| First flight attempt | 2001 (first attempt) |
| First-flight context | First launch attempt: June 2, 2001 (unsuccessful); first successful scramjet flight: March 27, 2004. |
| Retired | 2004 |
| Length | 3.66 m (12 ft) |
| Wingspan | 1.5 m (4.9 ft) |
| Height | 0.61 m (2 ft) |
| Empty Weight | 1,300 kg (2,867 lb) |
| Max Speed (Mach) | 9.6 |
| Speed evidence basis | Reported flight result |
| Max Speed | 11,265 km/h (7,000 mph) |
| Service Ceiling | 33,528 m (110,005 ft) |
| Engine | 1 × Scramjet (supersonic combustion ramjet) — boosted by Pegasus rocket dropped from B-52 |
| Production | 3 |
🌐 Operators
🔁 Variants
- X-43A — Mach 7 and Mach 9.6 scramjet flights
- X-43B — Cancelled larger demonstrator
- X-43C — Cancelled hydrocarbon-fuelled scramjet
⚔️ Armament
Overview
The X-43A set the speed record for an aircraft powered by an air-breathing engine, reaching Mach 9.6 on November 16, 2004. NASA reports an approximate speed of 7,000 mph (about 11,265 km/h). This is an air-breathing flight record, not a ranking of spacecraft reentry speeds. This unmanned experimental hypersonic aircraft demonstrated the viability of air-breathing scramjet propulsion, a technology that could revolutionize both military systems and access to space. NASA Hyper-X flight results.
Explore the units with the Mach speed converter: km/h, mph and knots. Mach depends on local air temperature; a model conversion does not replace the documented flight result.
Design & Development
Unlike rocket-powered vehicles, the X-43A used a supersonic combustion ramjet (scramjet) that breathes atmospheric air, compressing it through its forward body shape rather than mechanical compressors. Hydrogen fuel was injected into supersonic airflow inside the combustion chamber. The 3.7-meter-long vehicle was boosted to scramjet ignition speed by a modified Pegasus rocket launched from a B-52.
Flight-Test History
Three X-43A vehicles were built. The first launch attempt on June 2, 2001 failed when the Pegasus booster went out of control; the X-43A did not reach its intended test conditions. The first successful scramjet flight followed in 2004. The second flight on March 27, 2004 achieved Mach 6.8. The third and final flight on November 16, 2004 reached Mach 9.6—nearly 10 times the speed of sound—setting the current world speed record for air-breathing aircraft.
Armament
The X-43A carried no weapons. It was a pure research vehicle for scramjet propulsion technology. Each of the three vehicles was expended during its single test flight. The program provided flight data for subsequent air-breathing hypersonic research.
Video
Frequently Asked Questions
How fast is the X-43A?
NASA reports Mach 9.6 and approximately 7,000 mph (about 11,265 km/h) for the November 16, 2004 flight. It was a record for air-breathing aircraft. The km/h value is a rounded conversion of NASA’s approximate mph figure, not a sea-level conversion of Mach 9.6.
How was the X-43A launched?
It was mounted on a Pegasus rocket booster, carried by a B-52 Stratofortress. The booster accelerated it to scramjet ignition speed.
How many X-43A vehicles were built?
3 X-43A vehicles were built for NASA’s Hyper-X program. Two flew successfully.
Is the X-43A still in service?
No. It was an unmanned experimental vehicle for scramjet research.