The history of spaceflight has been marked by key eras of rapid progress in heavy-lift rocket development. These “golden ages” have seen the creation of vehicles that pushed the boundaries of payload capacity and enabled groundbreaking exploration feats.
The 1960s through the 1980s represented the first golden age, with the Saturn V, Space Shuttle, and Titan rockets greatly expanding access to space.
The 2000s have brought a new golden age with the development of super heavy-lift vehicles like NASA’s Space Launch System (SLS), and SpaceX’s Starship/Super Heavy.
This article explores the key vehicles and technologies of these golden ages of heavy-lift capability.
The First Golden Age: 1960s to 1980s
The 1960s through the 1980s can be considered the first golden age of heavy-lift booster development in the United States. This period saw the creation of powerful rockets like the Saturn V, Space Shuttle, and Titan family that greatly expanded payload capabilities to orbit and beyond.
The Saturn V
The pinnacle of heavy lift vehicle development occurred in the 1960s with NASA’s massive Saturn V rocket. Developed for the Apollo lunar missions, the Saturn V could loft an incredible 140 tons to low Earth orbit (LEO), a capability unmatched to this day.
The Saturn V consisted of three stages:
- The first stage, powered by five Rocketdyne F-1 engines, each producing 1.5 million pounds of thrust. The F-1 remains the most powerful single-chamber liquid-fueled rocket engine ever developed. Burning RP-1 kerosene and liquid oxygen, the first stage produced a total of 7.6 million pounds of thrust at liftoff.
- The second stage, using five Rocketdyne J-2 engines burning liquid hydrogen and liquid oxygen. The J-2 was the largest hydrogen-fueled rocket engine at the time. The second stage produced a total vacuum thrust of 1,155,800 pounds.
- The third stage, powered by a single J-2 engine. This stage would burn to depletion, placing the Apollo spacecraft on a trajectory to the Moon.
This powerful combination enabled the Saturn V to send the 100,000 pound Apollo spacecraft to the Moon. The total height of the Saturn V was 363 feet, taller than the Statue of Liberty. Fully fueled, it weighed 6.2 million pounds. The Saturn V flew 13 times from 1967 to 1973, with no failures after the unmanned Apollo 6 test flight.
Developing the Saturn V required overcoming numerous technical challenges. The F-1 engines suffered from severe combustion instability during development. The J-2 engines had to cope with pumping and burning liquid hydrogen, which has a very low density. The rocket’s guidance system, the IBM-developed Instrument Unit, was the first to use digital computers.
The Saturn V was a monumental achievement in rocket design and represented the culmination of the work of hundreds of thousands of engineers, technicians, and support personnel.
Space Shuttle
Development of NASA’s partially reusable Space Shuttle began in the 1970s. The Shuttle consisted of an orbiter spaceplane powered by three Space Shuttle Main Engines (SSMEs) and two large solid rocket boosters (SRBs).
The SSMEs, built by Rocketdyne, were the first reusable large liquid-fueled rocket engines. They burned liquid hydrogen and liquid oxygen and could be throttled over a wide range of power levels. Each SSME produced a maximum vacuum thrust of 512,300 pounds.
The SRBs, manufactured by Thiokol, were the largest solid rockets ever flown. Each booster contained 1.1 million pounds of propellant and produced an average thrust of 2.8 million pounds during its 2-minute burn. The SRBs were recovered from the ocean after each flight and refurbished for reuse.
While not as powerful as the Saturn V, the Space Shuttle could still lift an impressive 27.5 tons to LEO in its 15 by 60 foot cargo bay. It was the first spacecraft designed with reusability in mind. The orbiter and SSMEs were refurbished and reused after each mission, as were the SRBs after recovery.
However, the Shuttle proved to be more difficult and expensive to operate than originally envisioned. Refurbishing the orbiters and engines between flights was a time-consuming and costly process. The Challenger and Columbia disasters in 1986 and 2003 also cast a pall over the program.
Nevertheless, the Shuttle achieved numerous milestones during its 30-year operational life from 1981 to 2011. It launched satellites, conducted scientific research, and was instrumental in the construction of the International Space Station. The Shuttle demonstrated the feasibility, if not the practicality, of a partially reusable space transportation system.
Titan IIIC
The Titan family of rockets, originally developed as ICBMs, were repurposed as heavy lift space launchers starting in the 1960s. The Titan IIIC variant was created by adding two large solid rocket boosters to a modified Titan II core, quadrupling its payload capacity to LEO.
The solid boosters, called “UA1205”, were 85 feet long and 10 feet in diameter. Each contained 624,000 pounds of propellant and produced an average thrust of 1.2 million pounds. The core was powered by two Aerojet LR87 engines burning hypergolic Aerozine 50 and nitrogen tetroxide. These produced a combined thrust of 474,000 pounds.
Later versions like the Titan IV had stretched cores and even longer solid boosters. Some Titan IVs also used a Centaur upper stage powered by Pratt & Whitney’s RL10 engine for maximum performance. At its peak, the Titan IV could lift nearly 50,000 pounds to LEO.
The Titan family was notable for its use of storable hypergolic propellants. While these were highly toxic, they could be loaded long before launch and didn’t require the cryogenic facilities needed for liquid hydrogen and oxygen. This made the Titans suitable for the rapid launch requirements of their original ICBM role.
The Titans were workhorses for the U.S. Air Force, launching numerous military payloads from the 1960s through the early 2000s. NASA also used Titans for several high-profile missions, including the Viking and Voyager probes. The last Titan IV flew in 2005, marking the end of an era.
“We Only Need the Shuttle”: 1990s
With the Space Shuttle expected to replace all other rockets, the perceived need for new development was diminished. It wasn’t until the 2000s that a new generation of rockets and engines began to emerge.
The Second Golden Age: 2000s
Delta IV Heavy
The Delta IV Heavy, developed by United Launch Alliance (ULA), was a powerful heavy-lift rocket that played a significant role in the early 21st century. It was the largest rocket in the Delta family and was capable of launching massive payloads into orbit.
The Delta IV Heavy consisted of three Common Booster Cores (CBCs) strapped together, each powered by an RS-68A liquid hydrogen/liquid oxygen engine. These engines combined to produce over 2 million pounds of thrust at liftoff. The rocket’s upper stage was powered by an RL10B-2 engine, also burning liquid hydrogen and oxygen.
In its heavy configuration, the Delta IV could lift over 14 tons to geostationary transfer orbit (GTO) and 23 tons to low Earth orbit (LEO). This impressive lifting capacity made it a workhorse for launching large national security payloads, particularly for the National Reconnaissance Office (NRO).
The Delta IV Heavy was also selected to launch NASA’s Orion spacecraft on its first uncrewed test flight, Exploration Flight Test-1 (EFT-1), in December 2014. This mission saw Orion fly 3,600 miles above Earth, testing critical systems before returning for a splashdown in the Pacific Ocean.
Another notable mission was the launch of the Parker Solar Probe in 2018. The Delta IV Heavy, with an additional third stage, sent the probe on a trajectory that would take it closer to the Sun than any previous spacecraft.
However, the Delta IV Heavy was not without its challenges. Its inaugural launch in 2004 suffered a partial failure due to cavitation in the fuel lines, although the payload still reached orbit. The rocket was also expensive to produce and launch compared to newer competitors like SpaceX’s Falcon Heavy.
After a distinguished career spanning nearly two decades, the Delta IV Heavy flew its final mission in April 2024, marking the end of an era. While its retirement was a bittersweet moment, it paved the way for ULA’s next-generation Vulcan rocket, which promises to build on the Delta IV Heavy’s legacy of launching critical payloads to orbit.
The Delta IV Heavy demonstrated that a modular, heavy-lift rocket could be developed using existing technology and components. Its success laid the groundwork for the even more powerful rockets that would follow in its footsteps, pushing the boundaries of what’s possible in spaceflight.
Falcon Heavy
SpaceX’s Falcon Heavy rocket represents a major leap forward in heavy-lift capability. First launched in 2018, the Falcon Heavy builds upon the proven design and success of the Falcon 9, featuring a strengthened Falcon 9 core with two additional Falcon 9 first stages serving as strap-on boosters.
The Falcon Heavy’s 27 Merlin engines across its three cores generate a staggering 5 million pounds of thrust at liftoff, equivalent to approximately eighteen 747 aircraft at full power. This enables the rocket to lift nearly 64 metric tons (141,000 lbs) to low Earth orbit.
Like the Falcon 9, the Falcon Heavy incorporates reusability into its design. All three first stage cores are intended to be recovered and reused, either returning to land or landing on autonomous spaceport droneships at sea. This reusability is key to SpaceX’s goal of dramatically reducing the cost of access to space.
The side boosters separate earlier in the flight and return to land, while the center core continues to fire before separating and landing on a droneship. The second stage then delivers the payload to its intended orbit.
Since its debut in 2018, the Falcon Heavy has flown a number of significant missions demonstrating its capabilities, including:
- The inaugural test flight in February 2018 captured worldwide attention by launching Elon Musk’s Tesla Roadster into a Mars-crossing orbit.
- In April 2019, it launched the Arabsat-6A communications satellite, with all three boosters successfully landed.
- The June 2019 STP-2 mission for the U.S. Air Force delivered 24 satellites to three different orbits.
- In November 2022, the USSF-44 mission carried payloads for the U.S. Space Force including the TETRA-1 microsatellite.
These missions highlight the Falcon Heavy’s ability to deliver a variety of payloads to different orbits, while also demonstrating the viability of booster reuse.
The Falcon Heavy’s impressive capabilities open up exciting new opportunities for scientific exploration, commercial satellite deployment, and potentially human spaceflight. It offers the ability to launch heavier and more complex payloads, including larger satellites and space probes to distant destinations.
As SpaceX continues to refine the Falcon Heavy and push reusability further, the cost of heavy lift launches should continue to decrease. This will make ambitious missions more affordable and accessible to a wider range of government and commercial customers.
While SpaceX is developing the even larger Starship launch system, the Falcon Heavy will remain a critical heavy lift capability for years to come.
Space Launch System (SLS)
NASA’s SLS is a super heavy-lift launch vehicle that builds on technology from the Space Shuttle program. It is designed to be the agency’s flagship rocket for deep space exploration missions, including sending astronauts to the Moon and eventually Mars.
The SLS uses four RS-25 engines, which are upgraded versions of the Space Shuttle Main Engine, on its core stage. These engines are among the most efficient and reliable ever built, with a specific impulse of 452 seconds and a 100% success rate over 135 flights.
For its initial Block 1 configuration, the SLS will also use two five-segment solid rocket boosters derived from the Shuttle’s SRBs. Each booster produces 3.6 million pounds of thrust, for a total of 8.8 million pounds of thrust at liftoff – 15% more than the Saturn V.
In this configuration, the SLS can lift over 95 metric tons to LEO. Future versions, like the Block 1B with the Exploration Upper Stage and advanced boosters, will increase this capacity to over 130 metric tons, rivaling the Saturn V.
The first SLS mission, Artemis 1, launched 2022. This uncrewed test flight successfully sent an Orion spacecraft around the Moon to verify the rocket’s performance before carrying astronauts. Subsequent Artemis missions will establish a sustainable human presence on and around the Moon, laying the groundwork for eventual crewed missions to Mars.
Vulcan
United Launch Alliance (ULA), a joint venture between Boeing and Lockheed Martin, is ushering in a new era of spaceflight with its Vulcan rocket. Building upon the legacy of ULA’s reliable Atlas and Delta rockets, Vulcan represents a major leap forward in launch vehicle technology and capabilities.
At the heart of Vulcan’s design is a focus on power, versatility, and cost-effectiveness. The rocket stands an impressive 61.6 meters (202 feet) tall and can lift over 27,200 kg (60,000 lbs) to low Earth orbit in its heaviest configuration.
Vulcan’s first stage is powered by two BE-4 engines, developed by Blue Origin. These methane-fueled engines, each producing 2,447 kN (550,000 lbf) of thrust at sea level, represent a significant advancement in rocket propulsion. The rocket can also be augmented with up to six solid rocket boosters to provide additional thrust for heavier payloads.
The Centaur V upper stage, powered by two RL10 engines, provides the precision and restart capability necessary to deliver payloads to a variety of orbits. Vulcan’s modular design allows it to be customized for each mission, accommodating payloads ranging from small satellites to massive interplanetary spacecraft.
Vulcan incorporates several innovative features aimed at improving efficiency and reducing costs. One such innovation is the SMART (Sensible Modular Autonomous Return Technology) reuse system. With SMART, the BE-4 engines are designed to detach from the first stage after launch, descend under an inflatable heat shield, and be captured in mid-air by a helicopter for refurbishment and reuse. This partial reusability approach is expected to significantly reduce launch costs without the performance penalties of recovering the entire first stage.
ULA has also streamlined Vulcan’s production and launch operations. The rocket is assembled horizontally in a new factory at ULA’s Decatur, Alabama facility, using advanced manufacturing techniques to improve efficiency. At the launch site, Vulcan continues the use of the Vertical Integration Facility (VIF), allowing for payload integration and final preparations to occur in a protected environment just days before launch.
Vulcan’s maiden flight is planned for 2024. This mission will mark the beginning of a new era for ULA, as Vulcan begins to replace the company’s venerable Atlas and Delta rockets.
With Vulcan, ULA aims to maintain its reputation for reliability while reducing costs to stay competitive in an increasingly dynamic launch market. The rocket has already attracted significant commercial and government interest, with a manifest that includes missions for the U.S. Space Force, Sierra Nevada Corporation’s Dream Chaser spaceplane, and Kuiper broadband satellites for Amazon.
Starship/Super Heavy
SpaceX’s fully reusable Starship/Super Heavy launch vehicle is perhaps the most ambitious rocket currently under development. With a massive payload capacity and the ability to refuel in orbit, Starship is designed to enable large-scale exploration and settlement of the Moon and Mars.
The first stage booster, Super Heavy, is powered by 33 Raptor engines. Raptor is a next-generation full-flow staged combustion engine that burns liquid methane and liquid oxygen. Each engine produces over 500,000 pounds of thrust at sea level, for a total liftoff thrust of around 17 million pounds – more than twice that of the Saturn V.
The Starship spacecraft serves as the system’s second stage and is powered by six Raptor engines – three optimized for sea level and three for vacuum. Starship has a massive payload capacity of over 100 metric tons to LEO in a fully reusable configuration, with the potential for 150 tons or more with orbital refueling.
Starship is also designed to land on and launch from other worlds, enabling it to transport cargo and crew to the surface of the Moon or Mars. SpaceX plans to use Starship for its Artemis Human Landing System contract to return astronauts to the lunar surface.
Development of Starship is proceeding rapidly, with frequent test flights of prototype vehicles at SpaceX’s Starbase facility in Texas. The first attempted orbital flight test occurred in 2023.
New Glenn
Blue Origin’s New Glenn rocket, named after pioneering astronaut John Glenn, is a partially reusable heavy-lift launch vehicle currently under development. While not as large as the SLS or Starship, New Glenn will still provide a significant boost to the commercial launch market.
New Glenn’s first stage is powered by seven BE-4 engines. Each BE-4 produces 550,000 pounds of thrust, for a total of 3.85 million pounds at liftoff. The first stage is designed to be reusable, landing vertically on a ship at sea similar to SpaceX’s Falcon boosters.
The second stage is powered by two BE-3U engines burning liquid hydrogen and oxygen. These engines are derived from the BE-3 that powers Blue Origin’s New Shepard suborbital vehicle.
In a reusable configuration, New Glenn can lift 45 metric tons to LEO and 13 tons to geostationary transfer orbit. An expendable variant could potentially increase this performance. The large payload fairing, measuring 7 meters in diameter and up to 22 meters tall, allows New Glenn to accommodate bulky payloads.
New Glenn is expected to launch from Launch Complex 36 at Cape Canaveral Space Force Station, which Blue Origin has rebuilt from the ground up. The maiden flight is currently targeted for late 2024 or early 2025.
Looking Ahead
The new era of heavy lift vehicles and advanced rocket engines promises to transform our relationship with space. By reducing the cost of access to orbit and enabling new mission types, these systems will open up new opportunities for exploration, scientific research, and commercial activity.
The return of humans to the Moon and the eventual exploration of Mars will be made possible by the SLS and Starship. Ambitious robotic missions to the outer solar system can take advantage of the increased payload capacity. Large space telescopes and space stations can be launched in fewer pieces.
In the commercial sector, constellations of thousands of satellites for communications, Earth observation, and navigation will be deployed more quickly and cheaply. Space tourism and private space stations will become more viable. Mining resources from asteroids or the Moon could become economically feasible.
Of course, challenges remain. Developing these complex vehicles is a difficult and expensive endeavor. Failures and setbacks are inevitable. Concerns about space debris and the sustainability of large constellations will need to be addressed. Geopolitical tensions and competing national interests could hinder cooperation and progress.
Nevertheless, the future of space exploration looks brighter than ever. Just as the golden age of the 1960s and 70s laid the foundation for today’s achievements, the new era of heavy lift vehicles will enable the next great leaps for humanity in space. From the first woman and person of color on the Moon, to the first human footsteps on Mars, to permanent settlements beyond Earth, the rockets being developed today will carry us into that exciting future.
The legacy of visionaries like Wernher von Braun, Sergei Korolev, and Robert Goddard is being carried forward by a new generation of engineers and entrepreneurs. With hard work, ingenuity, and a spirit of exploration, there is no limit to what we can achieve. The golden age of spaceflight is just beginning.
