Nova: A brief history
Saturn-Nova (Original Nova) Comparison (NASA)
In the 1950s, the U.S. Air Force began working on a 1.5 million-pound thrust engine, which would later be known as the F-1. When NASA was formed in 1958, the agency considered a series of launch vehicles beyond the Saturn family. This new launch vehicle was designated as Nova.
NASA, Von Braun, and contractors conducted several design studies in 1959 and 1960. A common feature among the designs was the clustering of engines. Initially, Nova was designed with four F-1 engines and had a translunar payload capacity of approximately 24 tons. However, when the five-ton Apollo command module was finalized, the required translunar payload capacity increased to over 60 tons. Consequently, the number of F-1 engines increased from 4 to 8/9, giving it the designation Nova 8L.
Original Nova designs (http://www.astronautix.com/n/nova8l.html)
On May 25, 1961, President John F. Kennedy announced before a special joint session of Congress the ambitious goal of sending an American safely to the Moon before the end of the decade. Four mission modes were considered to achieve this task:
Direct Ascent: This method involved launching the spacecraft as a whole unit. It would then travel directly to the lunar surface, without first going into lunar orbit. After completing the mission, the astronauts would return to Earth in the ascent stage, leaving the descent stage back. This design would have required development of the extremely powerful Saturn C-8/Nova launch vehicle.
Earth Orbit Rendezvous (EOR): EOR required launching the lunar spacecraft in pieces aboard two rockets and assembling them in Earth orbit. Alternatively, the whole spacecraft could be launched to Earth orbit, then a second tanker vehicle would refuel the last stage of the lunar spacecraft’s launch vehicle. The rest of the trip would be the same as Direct—with one spacecraft landing directly on the one and part of it returning to Earth.
Lunar Surface Rendezvous: Two spacecraft would be launched in succession. The first, an automated vehicle carrying propellant for the return to Earth, would land on the Moon, to be followed some time later by the crewed vehicle. Propellant would have to be transferred from the automated vehicle to the crewed vehicle. It should be noted that this mode was never seriously pursued. Although the idea was discussed, it was not a leading option and did not affect NASA’s final decision.
Lunar Orbit Rendezvous (LOR): A single launch vehicle would launch a spacecraft that was composed of a command and service module and a lunar module. The common and service module would remain in lunar orbit while the lunar module would fly two astronauts to the surface and back to the command module. The lunar module would be then discarded. Landing the smaller spacecraft on the Moon minimized the total mass required to be launched from Earth.
An artist impression of an Apollo spacecraft that would have used Direct Ascent (NASA)
The three most studied mission modes (NASA)
Initially, NASA engineers preferred the direct ascent mode, primarily because the perceived risk associated with docking and rendezvous in lunar orbit appeared to be too great. Rendezvous—which had not yet been attempted in Earth orbit—was believed to be impossible in lunar orbit.
Original Nova 8L Specifications (Wikipedia) [NOTE: Data could possibly contain errors]
Eventually, as we all know, NASA decided upon the LOR mission mode. LOR had a launch mass requirement between the Saturn C-3 (EOR) and Nova 8L (Direct ascent). After extensive studies on modifying the Saturn C-3/Nova 8L, it was decided in 1961 to go forward with the Saturn option. Thus the Saturn C-5 (later known as the Saturn V) was developed. Although the decision to choose Saturn over Nova was influenced by several factors, including costs, the primary reason was that C-5 could be built in an existing factory outside New Orleans, later known as the Michoud Assembly Facility. Nova, on the other hand, would require entirely new factories.
Studies on using Nova as backups continued into mid 1962, but were soon dropped as the Saturn family found itself deep-seated with NASA.
Yet, that wasn’t the end of Nova. As the Apollo program progressed, Mars emerged as the next goal. Thus, Nova was redefined as the next launch vehicle after Saturn-V. The design objectives included a million pound payload capacity to LEO. Unlike the original Nova vehicle that was designed by NASA, the second series were studied under contact by two major rocket companies that did not receive production contracts for Saturn stages—General Dynamics (Convair) and Martin Marietta. Philip Bono from Douglas Aircraft also submitted unsolicited design proposals.
Nova designs from the second series of study (http://www.astronautix.com/n/nova.html)
The contractors were tasked to design a vehicle capable of launching a million-pound payload to LEO that explored all possible combinations of:
one versus two stages
use of existing (F-1A and M-1) engines versus higher thrust, higher performance engines
recovery and reuse of either or both stages
Martin Marietta provided the most comprehensive study, evaluating all possible combinations and considered advanced concepts such as plug nozzles and air augmented engines. General Dynamics proposed more conservative designs, using either existing engines or enormous conventional bell-chamber engines with thrusts in the 3 million pound class. Bono from Douglas proposed designs with significantly lower masses than those of the other two contractors.
Nova (second series) design characteristics by contractor (http://www.astronautix.com/n/nova.html)
Another major challenge associated with Nova was the erection and transportation of such a large vehicle. NASA had already selected and purchased land for Nova launch sites, north of Saturn V’s LC-39. Due to the enormous noise and vibrations that would be generated by a Nova launch, remote offshore or towed launch platforms were deemed essential. One exotic concept proposed launching Nova not from Cape Canaveral, but from launch tubes hollowed into the cliffs of Hawaii!
By the end of 1963, it became clear that funding after Apollo would drastically decrease. Additionally, NASA saw no foreseeable need for such a large vehicle, as studies indicated that solid rocket boosters strapped onto the Saturn C-5 could carry a million pounds to LEO. As a result, the Nova project was quietly canceled in 1964.
As political support for space exploration declined, such a large launch vehicle never materialized—until Starship came online.
(Fun fact: Starship V1 is taller than the original Nova designs and even some from the second series. Meanwhile, Starship V3 surpasses all previous rocket designs in height, with the exception of Sea Dragon, which matches its planned height!)
However, a few decades later, Nova was reborn. This time, it wasn’t a NASA contract, nor was it a massive rocket. But it did have one unique aspect: the 21st-century Nova is designed to be fully reusable.
Revealed in October 2023, Nova is a fully reusable medium-lift launch vehicle expected to debut in 2025 or 2026. Designed by the private American aerospace company Stoke Space, Nova will be able to place up to 5 tons into LEO—just a fraction of the original Nova’s capacity.
Stoke Space’s Nova (Stoke Space)
When fully stacked, the vehicle will measure approximately 30.5 meters (shorter than Starship’s upper stage, but 9.5 meters taller than Falcon 1).
The first stage will be powered by seven LNG/LOX engines and will perform a return to launch site (RTLS) after stage separation. The second stage, on the other hand, will be powered by a ring of 30 LH2/LOX engines. After completing its mission, the second stage will return to Earth, protected by an actively cooled heat shield as it passes through reentry.
Stage 2 Engine undergoing testing. This prototype consists of 15 engines (2022/Stoke Space)
Stoke Space’s Hopper2 (Stoke Space)
Why is it called an actively cooled heat shield? Instead of using a traditional ablative heat shield like those found on crew capsules, the second stage will be protected by a metallic heat shield. Since metal alone cannot protect against the extreme heat of reentry, the heat shield will be actively cooled using the propellant!
Stoke Space team with a prototype Stage 2. The heat shield and ring of engines are visible (Stoke Space)
Regarding development progress, Stoke Space conducted its first booster engine test in June 2024, while the first hopper test of the second stage took place in September 2023.
Nova’s first stage FFSC engine undergoing testing (Stoke Space)
As with any new launch vehicle, and given that it is designed to be fully reusable, Nova’s debut flight is sure to be an exciting event. After nearly 66 years since the original Nova was introduced to President Eisenhower, we might finally see the modern Nova fly. Although not confirmed by Stoke Space, I believe this name honors the legacy of the original design while inspiring a new generation to explore the vastness of space.
References:
This article contains input from the following sources:
Wikipedia
Encyclopedia Astronautica
National Air and Space Museum
