RF's Role In Flying The World's Fastest Plane

By John Oncea, Editor

RF technologies – especially in telemetry, avionics, communication, and aerodynamic sensing – are integral to the design, testing, and successful flight of the world’s fastest plane.

Through a combination of its trajectory and assists from Venus and the Sun, the Parker Solar Probe (PSP) is the fastest object ever made by humans, traveling at a speed of 394,736 mph. According to We Are The Mighty, that’s fast enough to travel from New York to Tokyo in less than a minute.

PSP – NASA’s first-ever spacecraft to be named after a living person, Eugene Newman Parker, professor emeritus at the University of Chicago – was launched on August 12, 2018. In addition to holding the speed record, PSP made history on December 24, 2024, by coming closer to the Sun than any other artificial object ever, reaching a distance of just 3.8 million miles from the Sun’s surface.

Orbital Today writes that the second-fastest human-made object ever made was NASA’s Juno spacecraft, launched in 2011. “In terms of speed, it significantly surpassed all previous spacecraft. During its closest approach to Jupiter, Juno reached a limit of 165,000 mph.” Three powerful solar panels facilitated the high-speed and stable operation of the probe.”

The third-fastest artificial objects ever made are the Helios Satellites, the first two satellites specifically designed to study the Sun which travelled at 157,000 miles per hour. “Designed in the 1970s, the two Helios satellites broke all spacecraft speed records and flew closer to the Sun than even the planet Mercury,” We Are The Mighty writes. “It only took the probes two years to get to the sun, and they transmitted information about the heliosphere until 1985.”

Rounding out the top four fastest human-made objects is … well … a manhole cover. More accurately, it was a nuclear hatch cover that was placed on top of an underground shaft being used to test nuclear weapons.

According to ZME Science, the Pentagon was conducting most of its nuclear tests underground due to worries about nuclear fallout. Under the direction of Robert Brownlee, the first subterranean test was the nuclear device known as Pascal A, which was lowered down a 500-foot borehole. However, the detonated yield turned out to be 50,000 times greater than anticipated, creating a jet of fire that shot hundreds of meters into the sky.

During the Pascal-B nuclear test of August 1957, a 2,000-pound iron lid was welded over the borehole to contain the nuclear blast. When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere. The plate was never found, and scientists believe compression heating caused the cap to vaporize as it sped through the atmosphere.

A high-speed camera, which took one frame per millisecond, was focused on the borehole because studying the velocity of the plate was deemed scientifically interesting. After the detonation, the plate appeared in only one frame.

Regarding its speed, Brownlee reckoned that “a lower limit could be calculated by considering the time between frames (and I don't remember what that was)” and joked that the best estimate was that it was “going like a bat (out of hell)!” Eventually, he estimated that the explosion, combined with the specific design of the shaft, could accelerate the plate to approximately six times Earth’s escape velocity, or about 125,000 mph.

Just how long the iron lid remained intact is unknown, and it was never recovered. Some say it was vaporized, others think it survived its ascent and made it into outer space, making it the first artificial satellite in history, mere months before the Soviet Union’s Sputnik 1.

But assuming it did travel at 125,000 mph for even a little bit, it was going 117,634.22 miles an hour faster than NASA’s X-43A Hyper-X, the fastest plane (crewed or uncrewed) in the world.

The Need For Speed

According to ScienceDaily, NASA achieved a milestone in aviation in 2004 when it flew the first successful hypersonic flights of a plane powered solely by its air-breathing engine – specifically, a scramjet. These flights, faster than Mach 5, offered a glimpse of a future in which air-breathing engines could deliver more nimble, cost-effective, and adaptable vehicles than traditional rocket systems, owing largely to their ability to draw oxygen from the atmosphere rather than carry it onboard.

Unlike rockets that must haul their oxidizer, scramjet aircraft can be lighter or carry greater payloads, transformative advantages for both high-velocity atmospheric travel and potential first-stage systems for reaching orbit. The X-43A program confirmed that scramjets could be throttled and managed more like aircraft engines rather than fixed-thrust rocket motors, NASA wrote at the time.

Tracing its origins to early wind-tunnel experiments and computational simulations in the mid-1990s, the Hyper-X initiative, responsible for the X-43A, began in earnest around 1996, according to NASA. Wind-tunnel testing, aerodynamic modeling, and scramjet inlet studies laid the groundwork. Three identical 12-foot lifting-body vehicles were built, each tailored for a single flight: two for around Mach 7, and one for Mach 10 performance.

The first flight occurred on June 2, 2001, when a Pegasus booster carrying the X-43A under a B-52 mothership failed and had to be destroyed due to control system issues, writes Wired. Investigations traced the failure to design-modeling errors that misjudged the booster’s flight-control capabilities in expected aerodynamic conditions. In response, engineers revised booster fin actuators, conducted refined wind-tunnel evaluations, and optimized propellant load so the drop altitude could increase from ~24,000 to ~40,000 feet, thereby reducing atmospheric loads, Smithsonian Magazine adds.

On March 27, 2004, the second X-43A flight validated the scramjet concept in flight. Released at ~40,000 ft from the B-52, the stack was boosted to ~95,000 ft using the Pegasus rocket. Once the booster separated, the scramjet ignited, firing for about 10 – 11 seconds and accelerating the vehicle to Mach 6.8 (~5,000 mph). The vehicle then glided for minutes to collect aerodynamic data before impact in the Pacific, establishing a world speed record for air-breathing flight.

Eight months later, on November 16, 2004, the third and final flight pushed boundaries further. Again launched from a B-52 at ~40,000 ft, the X-43A was taken by Pegasus to roughly 109,000 ft. The scramjet operated for ~10 seconds, propelling the craft to Mach 9.6–9.8 (~7,000 mph). Though brief, the burn provided critical data on thermal loads and hypersonic aerodynamics at intense speeds. That flight earned recognition by Guinness World Records as the fastest air-breathing vehicle.

RF’s Role In Breaking Speed Records

While aerodynamic and propulsion innovations rightly dominate the spotlight, radio-frequency technologies played essential but often unseen roles. Methods including telemetry, onboard communications, sensor interfacing, and flight-control data links ensured precise performance adherence and data acquisition throughout the mission.

• Telemetry & Data Transmission: During each ~10-second scramjet burn and long glide, hundreds of sensors fed data on pressure, temperature, strain, and shock-boundary interactions. RF telemetry was vitally employed to relay these high-bandwidth data streams to ground stations in real time, preserving data essential for post-flight analysis.
• Real-Time Monitoring & Control: Though unpiloted, the X-43A relied on pre-programmed control, with RF-mediated status feeds allowing mission controllers to monitor vehicle health and trajectory. Given the extreme flux and thermal gradients at Mach 10, these RF systems needed to be robust against electromagnetic interference, frequency shifts, and signal attenuation caused by plasma and ionized airflow.
• Navigation and Tracking: Tracking a ~12-ft vehicle gliding from ~110,000 feet at nearly 7,000 mph over hundreds of miles required precise RF detection. Ground and possibly airborne radar systems, complemented by onboard transponders, provided range, velocity, and position data critical for both flight safety (ensuring splashdown targets were met) and scientific observation.
• EMI-Hardened Avionics: Hypersonic flight produces intense thermal and plasma environments, which can compromise RF circuit performance. Designers incorporated shielding and RF-hardened components to ensure signal fidelity for guidance, combustion initiation sequencing, and sensor data pathways – critical across the brief, high-stress mission phases.

The synergy between hypersonic aerodynamics and RF communications underlined the necessity of integrated multidisciplinary engineering, from high-frequency signal design to hypersonic inlet geometry.

The Hyper-X program represented a high-risk, high-reward investment, estimated at around $230–250 million over seven years. It produced invaluable validation of scramjet performance, aerodynamic heating profiles, structural heating mitigation, combustion stability, and flight dynamics in hypersonic regimes.

Despite success, follow-on programs such as X-43C and X-43D were ultimately shelved. NASA reallocated aerodynamic research funding toward human spaceflight priorities, leaving hypersonics with a smaller fraction of the budget. Still, the data set gathered continues to inform design strategies for future reusable hypersonic vehicles, missile systems, and missions to orbit.

The X-43A’s experimental flights highlight how far the fusion of air-breathing propulsion, vehicle aerothermodynamics, precision control, and RF communication technologies can go. In a dozen seconds of scramjet burn, the craft voyaged through realms of flight once thought accessible only to rockets.

The RF frameworks that supported data telemetry, navigation, guidance, and system health monitoring were not ancillary – they were foundational. They ensured that hypersonic flame, sonic shock, and engineering conjecture translated into measurable, reliable performance.