Rocketship X-M – Design and Performance of the RX-M


n May 26, 1950 the Rocketship X-M expedition to the Moon was launched from the planet Earth.


Although frequently over shadowed by the flight of the Rocketship Luna that occurred a month later, the RX-M was actually the first attempt to reach the moon in 1950.

In the intervening years most of the technical specifications of the RX-M has been lost or destroyed. This post is an attempt to use publicly available historical documentation about the RX-M and attempt to derive some performance and flight data as well as address the controversy surrounding this early attempt to reach the moon.

One of the most frustrating issues about the flight of the RX-M is that virtually every thing know about it is derived from a single source, the surviving film footage of the press conference given by the RX-M crew shortly before it’s launch. And most of that information is vague, contradictory or meaningless personal information about the crew. We have attempted to derive some supplementary performance data gleaned from the radio transmissions received on Earth during it’s voyage. But our results are conjectural at best.

Rocketship XM Staffing Lloyd Bridges, Osa Massen, John Emery, Noah Berry Jr. You heard this year's Oscar Winner for Best Actor credit his father for his acting career. Well here he is folks. Third from the left: Lloyd Bridges.

The RX-M was a multistage rocket launching from White Sand New Mexico Proving Grounds. Detailed examinations of photographs of the RX-M give a estimated height of 180 feet (55 meters) with the cylindrical main body 37 feet (11 meters) in diameter at its widest point. At the head of the rocket are two stubby wings or fins that increase the width of the rocket to 44 feet (14 meters).  Running from the rockets mid point down to its base are more stabilizing fins.


There are two crew spaces in the rocket. The “Motor Room” where where the crew enters the rocket and then ascends up a ladder to a gyroscopic stabilized spherical control room.

The first stage appears to take up the lower 1/3rd of the rocket. The mass of it engines, crew, cargo, structure and equipment is completely unknown. However we can make a estimate the total mass of both stages.

During the press conference it was stated that the rocket would assent to 300 miles (482803 meters) in 7 minutes before making a 90 degree turn to circle the Earth. Why do this instead of performing a more efficient launch to the east was not explained. Since average acceleration is calculated by dividing the distance traveled by one half the time squared (a = D/(.5 * t^2)) we get a average acceleration for the rocket of 5.47 meters/second.

482803 /(.5*420^2) = a = 5.47 m/s

We also know from the launch checklist that the automatic pilot was set to lift off with 2300 tons of thrust.  2300 tons of thrust translates to a thrust of 4600000 pounds or 2086524.902 kilogram or 9281325.138 newtons of force. You can calculate the total mass the rocket could lift by dividing the force by the average acceleration. (mass = F/a  = 9281325.138 / 5.47 = 1696768.76 kg)

1696768.76 KG is equal to 3740734.79 pounds or 1870.36 tons

For propellants the RX-M uses a fuel mixture of mono-atomic Hydrogen, Ozone and a mysterious substance only referred to as “A”.

During the pre-flight press conference Dr. Van Horn, the only woman on the crew, is credited with developing a means of stabilizing mono-atomic hydrogen for fuel. Today, most chemical rockets use dihydrogen or molecular hydrogen instead of Mono-atomic Hydrogen because the mono-atomic form of hydrogen is extremely unstable and tends to explode when you glance at it too hard.


You’re glancing too hard.

The press conference also says the rocket uses oxygen as a oxidizer but the tanks in the Motor Room are clearly labeled O3 which is actually Ozone. O2 is the common form of oxygen and is what 21% of the Earths atmosphere is made of. Ozone only a trace component of the atmosphere as it naturally decays fairly quickly into O2. Ozone is also difficult to store and is also unstable. The process Dr. Van Horn developed keep both these chemicals stable has since been lost.

That leaves the final component in the fuel mixture, the mysterious substance “A”. This substance actually came in three separate forms, A12, A14 and A16. Presumably the different forms of “A” were used to destabilize the mono-atomic hydrogen and ozone and cause them to react in the rocket engines.


Once the RX-M reached a altitude of 360 miles telemetry indicates it is traveling at 3400 mph (5471.77 kph). But this is about 4.5 times slower then the velocity needed to circle the Earth. They jettison the first stage without realizing that it still has fuel and left the engines running. The still accelerating first stage almost crashed into the second stage.  Fortunately the crew saw the incoming first stage and quickly engaged the second state engines to dodge. The rocket then slowly increased velocity and altitude to achieve Earth orbit.


Although it is not clearly stated it seems that the RX-M had to maintain a constant acceleration as it spirals out from the earth.

After 14 hours of flight, and the usual encounter with a swarm of meteorites common to that era, the RX-M was about 112000 miles from earth when the rocket engines just stop. For several hours the crew is not able to get the rockets started again and the rocket remains suspended half way between the Earth and the Moon in complete defiance of Newton’s Laws of Motion.

Eventually they recalculate the fuel mixture and rearrange some of the fuel tanks and are able to get the engines started again. But something goes wrong and the RX-M accelerates several times faster then the meager .5 G it used on takeoff. How fast is unknown

The unexpected acceleration toss the crew about the control cabin and rendered them unconscious.

The rest of the narrative of the RX-M rest on a final radio report received on Earth before the rocket was presumably destroyed.

According to the radio report the crew awakens a few days latter to find they are in the vicinity of the planet Mars. They land on the red planet and discover the remnants of a civilization of humanoid Martians. They detect a high background level of radiation and the blasted remains of a Martian city and deduce that a Atomic War has taken place. Later they encounter the radiation scarred and blinded survivors of the Martian Atomic War and several members of the crew are killed by the aggressive savages.

RXM-MartianAttack RXM-Martians

The remaining crew liftoff and set course back to Earth. Unfortunately their fuel runs out on final approach. In the few remaining minutes the crew has before the rocket begins a fiery plunge into the Earth atmosphere, they send a final radio transmission detailing their adventures along with a moralizing lesson on the dangers of nuclear war.


The head of the RX-M project then pronounces that tomorrow work on the RX-M2 will commence.

Thus ended the tragic flight of the Rocketship X-M.

After the RX-M disaster and the successful launch and return of the Rocketship Luna a month later on June 27, 1950 the funding for the RX-M program was halted and the project was abandoned.

The fuel stabilization formulas and catalysts used to propel the rocket were lost.

As time passed the project was largely forgotten. The remaining members of the project were accused of negligence for their haste in trying to beat the Luna to the Moon. Some even claimed the rocket was thrown together in only 18 days to beat the Luna to the moon.

In reviewing contemporary news clippings there is virtually no reference to the RX-M program before a Life Magazine article in January 1949.

Rocket to the Moon – Man may travel to Earth’s satellite within 25 Years









Although the name of the rocket is never mentioned, this is undoubtedly a press release for the RX-M program.

The loss of the rocket and all of its crew was also noteworthy in that Congress didn’t involve itself in investigating the program. After all, it was a government program launched from the White Sands Proving grounds.

Dr. Ralph Fleming the project director went on to have a colorful career cattle ranching in Montana, trying to receive radio messages from the Red Planet Mars, chasing Flying Saucers, and claimed to fought invaders from Mars in the sand pit behind his house.

Morris_Ankrum_01_Rocketship_X-Mmorrisankrum_head1441952-red-planet-mars-015-morris-ankrumMorris-Ankrum-74_z 2857184,MRum1fCz2O6_eLuS_9LWpLPsl+_dc+gypBT4ClHIYRtBjmePWMNeFgd3fPSbJjq6wzKb_fFyuTeHO9i+18XSGw==

There were also rumors that the crew was not killed. The famous marine diver Mike Nelson close resemblance to Col. Floyd Graham was one source of these rumors. Another was that the actor that played in the Life and Legend of Wyatt Earp was often mistaken to be the astronomer Harry Chamberlain.


In summary, here are the few pertinent facts we know concerning the Rocketship X-M

Length 180 feet / 55 meters
Width of Main Body 37 feet / 11 meters
Wing Span 44 feet / 14 meters
Dry Mass Unknown
Dry Volume Unknown
Dry Volume Unknown
Propellant Mass Unknown
Propellent Volume  Unknown
Propellent Volume Unknown
Estimated Total Mass 1870.36 tons / 3740734.79 pounds / 1696768.76 KG
Exhaust Velocity Unknown
Specific Impulse Unknown
Max Acceleration Unknown
Mass Ratio of Unknown

Reference Materials:

Rocketship X-M DVD

Rocketship X-M Instant Video

Atomic Rockets

Spaceship Handbook

The Dream Machines: An Illustrated History of the Spaceship in Art, Science and Literature

RXM-LobbyCardItal rx_m_destinazione_luna_lloyd_bridges_kurt_neumann_001_jpg_pwjm



RXM-LobbyCard4  Rocketship XM Staffing Lloyd Bridges, Osa Massen, John Emery, Noah Berry Jr. You heard this year's Oscar Winner for Best Actor credit his father for his acting career. Well here he is folks. Coming up through the rockership passageway: Lloyd Bridges.RXM-LobbyCard8 RXM-LobbyCard11

RXM-LobbyCard3 RXM-LobbyCard2


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