Old Mogul Balloon

Mogul train

What was Project Mogul?

Project Mogul was an attempt to use sensitive microphones to listen for sounds from Soviet atomic bomb tests. Because it was spying on Soviet activities, it was classified until the 1990s.

What were the balloons used in Project Mogul?

While the team was still proving the concept, they were using makeshift balloon trains (right) made of parts of multiple RaWin weather balloons (left). Once the concept was proved, they developed the Skyhook balloon made of a huge plastic bag filled with helium.

What is a RaWin Weather Balloon?

Rawin Balloon


The RaWin (RADAR Window) balloon (Or RaWinSonde - sounding balloon) was a weather balloon (left) developed by the US Navy for the purpose of gathering data for weather forecasts. It has:

  1. An instrument package and a radio transmitter to send weather data back to the base.
  2. A RADAR corner reflector (window) so RADAR can track its position.
  3. A parachute (red) to land it gently for reuse.

RADAR tracks the position of the RaWin balloon to gain valuable data on what the winds in the upper air are doing.

When the RaWin balloon goes too high, the balloon bursts and the parachute brings it back down.

These were in general use by the Navy by the end of World War II.

The Army was using something else, so they did not know about the RaWin balloon.

How did the Mogul team assemble the first few balloon trains (right)?

Largely they had to use what they had available and kludge them together to get them into the air.

Each early Mogul baloon had 20 to 24 neoprene aerostats (balloon envelopes) from RaWin balloon sets connected in a long chain to provide enough lift to attain high altitudes. Each circle in the diagram on the right is one aerostat.

octohedral reflector

Each early Mogul baloon had 3 RADAR corner reflectors from RaWin balloon sets connected in a chain to reflect RADAR beams back to the RADAR stations. Each octohedron in the diagram on the right is one reflector.

One octohedral corner reflector is shown at left. There are three foil planes at right angles to each other in each octohedron, forming 8 corner reflectors, This reflects a RADAR beam coming from any direction directly back to the RADAR set that sent the beam.

Three reflectors were needed to get a reliable track at high altitudes.

roswell adheswive tape

The octohedral corner reflectors were assembled using adhesive tape purchased at a craft store. That tape had decorative symbols on it which some people interpreted as alien characters. But the author of this page had a roll of that same tape sold for package wrapping with the same symbols on it in the mid 1950s. He made a sketch of it when he had the tape (right).

The foil used to make the octohedral reflectors was aluminized polyethylene. This was a new material at the time. Witnesses thought it was metal that magically returned to its original shape.

skyhook balloon

Each early Mogul balloon beginning with #4 had several parchment paper parachute units and an instrument package at the bottom. Since it was not known in what order the balloons would burst, enough parachutes were provided to keep the entire train vertical. Each rhombus (diamond) in the diagram at right is a parachute.

After the first eight balloon trains were launched, another group entered the team and replaced the train with the Skyhook constant altitude balloon design (right). These were then used for years for high altitude research.

The Skyhook ballon was implicated in many UFO cases, including Farmington NM, Sandy Hook NJ, and Fort Knox KY (The Mantell case).

tren sizes

Size chart

How big was this Mogul balloon train?

The diagram at right shows the relative sizes of objects:

The Statue of Liberty is 305 ft tall.

The Washington Monument is 555 ft tall.

The Eiffel Tower is 1055 ft tall.

The Mogul Balloon train (right tall thin object) is 657 ft tall.

This explains why the debris field was so large.
 If the balloon train just laid down when it came down, it would leave a debris field 657 feet long.

What was the timeline for Mogul balloon launch #4 and the discovery of its crash site?

Mogul balloon #4 was launched on 06/04/1947. It was lost to RADAR later that day. The recovery team did not find it.

After a few days, the sun and elements had turned the neoprene aerostats brown and made them brittle.

Mac Brazel found the debris sometime around 06/14/1947. He waited until his next trip into town (and after he heard of the 06/24/1947 Kenneth Arnold case) and reported it to the sheriff on 07/07/1947.

The matrerials found by Brazel included disintegrating rubber, nylon ropes, rather tough paper, a silvery metal that could not be creased, balsa wood, and adhesive tape with symbols on it.

When the sheriff reported the debris to Roswell AAC base, the base sent out a team to collect all of the material found at the site on 07/07/1947.

On 07/07/1947, the Roswell AAC Base issued a press release saying that the base might have possession of a "flying disc". The Roswell Daily Record published the story on July 8, 1947

After the story was published, the weather officer told them that he recognized the debris as belonging to a RaWin weather balloon.

On 07/09/10947, the Roswell Morning Dispatch prints a story saying the UFO was nothing but a weather balloon. A photo in the story shows Ramey and Marcel holding the damaged corner reflector.

Why was this case designated "solved" for 20 years before it was reopened in the 1970s?

Those who agreed with the RaWin weather balloon identification did not know how much debris was found.

Why did it take so long to notice that the debris field was too large to be just a RaWin balloon?

The main reason was that those who knew the size of one of them did not know the size of the other.

  1. Ramey, Marcel, and the others on the base didn't know how small a RaWin weather balloon was.
  2. The weather officer and the navy didn't know how big the debris field was.
  3. The weather officer saw only the material that Ramey and Marcel brought to the press release.
  4. Because Project Mogul was secret, nobody knew that there was a balloon train or how long the balloon train was.
  5. The reporters didn't know the sizes of the balloon train, the debris field, or the RaWin balloon.
  6. The Mogul balloon trains were built out of RaWin balloon parts, so the weather officer recognized them.
  7. Nobody questioned the difference in the sizes until the late 1970s,

You need 24 RaWin balloon kits to build a Mogul balloon train.


"Hello.... Rent-A-Saucer?"
"Can you send another UFO?"
... "This one fell apart!" ...
"Maybe it's because this one
was made of nothing but balsa
wood, weird foil, rope, tough
paper, purple adhesive tape,
and disintegrating rubber." ...
"How? Well, we started the
warp field... And then it just
went 'DRICK!' and fell apart."

China Spy

Why do we think the crash was a Mogul balloon train instead of a spacecraft?

Maybe it's because the debris contained only balsa wood, plastic struts, purple adhesive tape, weird foil, rope, disintegrating rubber, and parchment paper.

Nothing spaceworthy could be made of only these materials.

Notice that the Mogul balloon train contained only balsa wood, plastic struts, purple adhesive tape, weird foil, rope, neoprene rubber, and parchment paper.

For what purpose would space aliens need balsa wood, plastic struts, purple adhesive tape, weird foil, rope, neoprene rubber, and parchment paper?
 Maybe they wanted to build a fake Mogul balloon train.

What about that weird foil that would not hold its shape?

Get an empty Ruffles potato chips bag and turn the bag inside out. Then try to make it hold a crease like aluminum foil does. It behaves just like this foil was reported to do.

What about the claim that the weather balloon parts were substituted for the crash debris?

No substitution was needed. The Mogul balloon train was made of RaWin balloon parts.

Why do many people still believe that this was a case of extraterrestrial activity?

There are die-hards who want every famous case to be extraterrestrial activity.

Are there any other cases of spy balloons that are more well known?

A Chinese spy balloon (right) crossed US airspace from 01/28/2023 to 02/04/2023.
An Air Force F-22 shot it down on 02/04/2023 over the Atlantic Ocean east of Myrtle Beach SC.
Network and news TV covered this extensively.
This was never considered to be a UFO because they knew almost immediately what it was.

On 02/10/2023, another object was shot down off the Alaskan coast.

On 02/11/2023, another object was shot down over the Yukon territory in Canada.

On 02/12/2023, another object was shot down over Lake Huron.