American Military University

Util iz ing Thermal Airships to Create Alternative Vehicles for Suborbital

Spacecraft

Gary C. Booker (3092840)

SPST499 – Senior Capstone

Professor David Syndergaard

25 November 2012

TOPIC OUTLINE

I. Introduction

II. Historical Context: Excelsior II and Red Bull Stratos

III. Current Dilemmas

1. The Envelope-Environment Pressure Differential Problem

2. The Impending Helium Shortage

3. An analysis of Johnathan Powell's Proposed Approach

IV.The Thermal Airship as a solution

V. A Proposed Design

VI.Closing Remarks

Introduction

Rocketry is unquestionably the most reliable ways and means of space travel that humanity has

ever harnessed. It became very apparent early in human history that such a means would eventually

prove to be successful. The Earliest record of a human attempting to travel into space is the legend of

Wan Hu, who was allegedly an emperor that tried to travel into space by attaching several kites to a chair

heavily rigged with rockets1. Wan Hu's attempt ended with a large explosion, with both the craft and

Wan Hu disappearing and Wan Hu's fate unaccounted for2. Wan Hu's story, whether true or not, is an

illustration of the story of humans and rockets that would follow: Rockets have taken us to the moon and

back and have allowed us to build planes that fly at incredible speeds, but have also produced some of

history's most horrible transportation accidents. It is for this reason that the spaceflight community at-

large should question whether or not rockets should remain status quo, or become relegated to bygone

eras as the spaceflight community attempts to make spaceflight accessible to the tourist.

Another idea that has been proposed is using balloons and airships to explore space. Balloons have

much higher altitude capabilities than even the most sophisticated of jet aircraft, such as the U2 and SR-

71. The highest manned hot air balloon flight, piloted by Vijaypat Singhania, reached an altitude of

21,290 meters (69,849 feet) in the year 20053. The highest manned lighter-than-air gas balloon flight has

been set by Felix Baumgartner of the Red Bull Stratos project at an altitude of 39,045 meters (128,100

1 Joe Havely. “China's Ming Dynasty Astronaut,” CNN (December 22nd 2012). (Retrieved October 19th 2012)2 Ibid.3 “FAI News 15/05,” Federation Aeronautique Internationale (December 21st 2005) (Retrieved October 19th 2012)

feet) on October 14th 20124. While these missions establish lighter-than-air ascent vehicles as a force to be

reckoned with in reaching high altitudes, this modus operandi has much growing up to do in order to be

able to compete with the abilities of rockets. These altitudes, while high enough to experience the

blackness of space, the curvature of the Earth, and the sensations of motion expected from Einstein's

theories of special relativity, it is far short of the accepted definitions of the edge of space used by the

Federal Aviation Administration in the United States, and Fédération Aéronautique Internationale. The

problems that face the modality of lighter-than-air based ascent will be explored in discussion to follow

later in this paper.

Historical Context: Excelsior II and Red Bull Stratos

The Space Race was heating up in 1960, and the United States and the Soviet Union were fully

committed to the task of establishing space supremacy. While a clear objective was not yet set, both

superpowers were seeking to gain the ultimate high-ground before the other could do so, and were

conducting experiments that would get a man into orbit. One of the essential experiments conducted by

the United States would be the Air Force's Project Excelsior.

On Aug. 16, 1960, Capt. Joseph W. Kittinger Jr. jumped from an open

gondola wearing a pressurized suit, 102,800 feet over Tularosa, N.M., and

landed unharmed 13 minutes, 45 seconds later as part of Project Excelsior.

He fell freely for 84,700 feet and reached a speed of 614 miles per hour

4 “World Record Jump: Felix Baumgartner Breaks The Speed Of Sound In Freefall.”

before opening his parachute. This was the highest jump and longest free

fall on record. Project Excelsior was formed in 1958 to study and solve high

altitude escape problems as jets became increasingly high performance... In

freefall for four and a half minutes, Kittinger fell at speeds up to 614 mph,

exceeding the speed of sound. He experienced temperatures as low as -94

degrees Fahrenheit. Kittinger opened his parachute at 18,000 feet and

landed safely in the New Mexico desert after a 13 minute, 45 second

descent. Project Excelsior successfully proved the new parachute system,

the Beaupre Multi-Stage Parachute, would solve the problem of high

altitude escape by crewmen5.

Joseph Kittinger's balloon flight and jump helped to develop the spacesuit technologies that would be used

by astronauts, as well as the parachutes used during re-entry. This feet has since been duplicated by Felix

Baumgartner (mentored by Col. Kittinger during the Red Bull Stratos Project), whose October 14th flight

and jump surpased Kittinger's altitude, using a lighter pressurized suit and a more sophisticated gondola.

The mission profiles of Excelsior II and Red Bull Stratos are those of suborbital spaceflights that

do not actually reach the recognized boundaries between the earth's atmosphere and space. But what if

the technology to reach the FAA and FAI boundaries using lighter-than-air technology emerges? These

missions were much lower in costs in comparison to even the most inexpensive of spaceflight-capable

rockets. Improvements in lighter-than-air technology could allow these mission profiles to extend higher

5 “Project Excelsior,” United States Air Force (nd). (Retrieved October 19th 2012)

in altitude to the point where balloons can become viable spacecraft.

Current Dilemmas

There are three problems that impede the development of lighter-than-air spacecraft:

1. The Envelope-Environment Pressure Differential Problem

2. The Impending Helium Shortage

These problems have been addressed by Johnathan Powell of JPAerospace. His proposed approaches will

be examined.

The Envelope-Environment Pressure Differential Problem

Radiosondes are launched by meteorologists on a regular basis. Most of them burst before

reaching the stratopause. The reason is because of basic fluid mechanics. The Ideal Gas Law (also known

as the Equation of State) holds that PV = nRT, where

• P is pressure (Pa.)

• V is volume (m3)

• “n” is the number of moles

• R is the Ideal Gas Constant (8.31 J/mol·°K)

• T is absolute temperature (°K)6

The variables of state are directly proportional to one another. As a balloon filled with lighter-than-air

6 Daniel L. Roger et al., Chemistry: Principles and Practice (Belmont: Brooks-Cole, 2009), 233-235

gas (usually helium) rises through the atmosphere, it continuously and gradually encounters areas of lower

pressure and temperature. However, the pressure inside of the balloon remains the same. As the result,

the balloon expands as the gas inside of the balloon expands, eventually causing most weather balloons to

burst at upper-stratospheric altitudes7.

Today's gas balloon envelopes do not have the capability of withstanding the expansion enough to

rise higher than current altitudes. In order to use gas balloons to pass the edge-of-space as defined by the

world's relevant accrediting bodies, new materials would have to be developed that are capable of

continuously expanding as the balloon rises without bursting. While such a prospect cannot be ruled out,

it is one that would require extensive materials science research.

The Impending Helium Shortage

Even if the gas-balloon burst problem is technologically solved, it still remains that an enormous

amount of helium is necessary to make this happen. Helium is becoming an increasingly precious source.

Tom Welton, a professor of sustainable chemistry at Imperial College,

London, believes that a global shortage of helium means it should be used

more carefully. Helium cools the large magnets inside MRI scanners - the

medical devices that provide doctors with detailed images of what is

happening inside their patients' bodies. Prof Welton told BBC Radio 4's

Today programme: "We're not going to run out of helium tomorrow - but

7 Nicholas Giordano, College Physics (Belmont: Brooks-Cole, 2012), 484-485

on the 30 to 50 year timescale we will have serious problems of having to

shut things down if we don't do something in the mean time.8”

Hydrogen is the only readily available lighter-than-air gas that is equally effective as helium, but the

practice of using hydrogen in balloons has been abandoned by most balloonists & aeronauts since the

Hindenburg disaster in 1937, and similar disasters that followed. If the natural gas production does not

increase to meet the worldwide helium demand, then the widespread usage of helium gas balloons to fly

aloft into space is not a logistically pragmatic strategy.

An analysis of Johnathan Powell 's Proposed Approach

Johnathan Powell, founder of JPAerospace, advocates traveling to earth orbit using airships in a

three-part mission architecture. In the first part, he proposes a “high flying good year blimp” that will

travel up to an altitude of 42,672 meters (140,000 feet)9. The second part of Powell's mission provile

features the ship making a rendezvous with a craft known as the Dark Sky Station. The Dark Sky Station

serves as a “permanent, crewed facility parked at 140,000 feet.10” It is a departure station that allows

crews to transfer from the first stage airship to the orbital airship. The third part of Powell's mission

architecture is an enormous airship that is over a mile long, and will use buoyancy to climb to over

200,000. From there, it accelerates slowly to an orbital velocity and reaches its orbit after a few days11.

Powell's space strategy builds upon the gas ballooning modus operandi of Project Excelsior, just as

8 Mick Robson. “Helium shortage prompts scientist's use warning,” The British Broadcasting Company (September 21st 2012) (Retrieved November 1st 2012)

9 Johnathan Powell. Floating to Space: The Airship to Orbit Program. Burlington, ON: 2008: p.13.10 Ibid.11 Ibid.

the Red Bull Stratos Project, but clearly is designed to go beyond the edge of space and make orbits as

with any other spacecraft. His idea is to develop an orbital airship in the stratosphere that could never be

built upon the ground because of its enormous size, that will perform a “balancing act between

acceleration and climbing to reach orbital altitude and speed simultaneously.12”

Powell, like most advocates of Space Ballooning, see lighter-than-air vehicles as a low cost

alternative to flying. But how much will it cost to build such an enormous set of airships with rising

helium costs? And just what would the logistics of assembling what would be the largest spacecraft the

world has ever seen and never touches the ground look like? The main reason why John Houbolt

advocated Lunar Orbit Rendezvous in contrast to the Earth Orbit Rendezvous and Direct Ascent modes

of traveling to the moon was because the logistics of landing an enormous rocket on the moon and

relaunching it was just too much of a logistical hassle. One could make a reasonable argument that the

large craft is a concept that works well on paper, but could spell irreconcilable difficulties if implemented.

However, Powell's concept of slowly accelerating into using small electric rocket motors, while gaining

altitude using buoyancy should certainly be taken seriously:

The airship supports the weight of the rocket. The main use of the rocket

engines in the orbital airship is not for climbing. They are for acceleration.

But this will not be the acceleration of a dragster. Passengers on board will

not even feel it. The airship does use some of the energy to climb13.

12 Ibid, p.32.13 Ibid.

The Thermal Airship as a solution

Thermal Airships combine the attitude control of airship gondolas with the lift technology of hot

air balloons. Hot air balloons gain lift by using heat to make the air inside of the balloon envelope less

dense, and consequently lighter, than the air outside of the envelope. Vijaypat Singhania's world record

hot air balloon altitude of 21,290 meters (69,849 feet), part of Singhania's “Mission Impossible 70K”

Project, is slightly more than half of Felix Baumgartner's altitude of 39,045 meters (128,100 feet), but is still

much higher than the highest flying jet aircraft. Like the Gondola of Red Bull Stratos, Singhania's

Gondola was pressurized and filled with several avionics to assist with flying the balloon. Why wasn't

Singhania's balloon able to travel as high as the Red Bull Stratos Balloon? Because hot air balloons need

oxygen, which becomes extremely scarce in the stratosphere.

The MI70K balloon burned Jet 1 Kerosine during it's ascent, and Propane during its descent 14. Jet

1 Kerosine has a far greater amount of energy per unit mass than propane, and was a wise choice for a fuel

for a mission profile of reaching a desired altitude of 70,000 ft, where the heat of the vehicle would have

continued to provide lift after fuel burnout. But even the ambitious altitude of 70,000 ft is not high

enough for the purposes of spaceflight.

A thermal airship must be able to continue to burn well into stratospheric ascent. To do this, a

thermal airship must use an oxidizer just as rockets use. This paper will propose a flight profile of the

“thermal spacecraft” of three parts:

1. Atmospheric Ascent – The thermal spacecraft will ascend to into the atmosphere

14 “The Project,” Mission Impossible 70K (November 22nd 2005). (Retrieved November 11th 2012)

2. Oxygenated Ascent – The thermal spacecraft will continue the burn by providing oxygen from

storage, ending it's burn near the flight apogee.

3. Descent and Landing – The thermal spacecraft will slowly descend back to the surface.

Because hot air balloons and thermal airships are not enclosed, it will allow for some air to escape

as the atmospheric pressure outside of the balloon lapses. It would also allow for the air inside of the

envelope to remain less dense than outside air if the hot air balloon can continue to heat just enough gas

particles inside of the envelope to remain buoyant as the balloon passes the stratopause and ascends into

the mesosphere.

A Proposed Design

This paper will propose a design to be carried out in an experiment. This experiment would

construct a model thermal-airship and its purpose would be to ascend beyond the stratopause and into the

mesosphere, which is higher than any balloon has flown according to FAI records as of November 25th

2012. If successful, the experiment would establish evidence that airships can be used as spacecraft by

FAA and FAI standards. The elements of the design are as follows:

1. An envelope and a gondola, which is the basic design of most hot air balloons and thermal

airships/dirigibles. However, the gondola must be pressurized and enclosed (see Illustration 1).

2. The gondola will carry a cabin for passengers and a pilot, as well as an oxidizer and fuel to burn.

A gondola shaped like the Mercury and Gemini capsules would allow the gondola to be sectioned

off accordingly (see Illustration 2).

1. The bottom section of the gondola would carry the oxidizer and fuel pump. Some proposed

combinations would be:

1. Standard Jet 1 Kerosine & Pure Oxygen (proposed earlier in the paper)

2. Combinations commonly used in spacecraft:

1. Hypergolic fuel/oxydizer combos such as hydrazine (N2H4) and nitrogen tetroxide

(N2O4)

2. A monopropellant such as high concentration hydrogen peroxide (H2O2)

2. The middle section of the gondola would contain the cabin and would carry the passengers.

The number of passengers is immaterial to this discussion, as it would vary as differences in

design would allow. But the cabin should either contain an oxygen system so that the

passengers and pilot may breathe, or support for spacesuits worn by the passengers and pilot.

There should also be a means of controling the temperature of the gondola, and it might be

efficient to construct a passive heating system that is able to utilize the heat coming from the

burn of the engines as a means of regulating temperature as the airship ascends into the colder

parts of the atmosphere. There should also be a closed-loop control system that monitors all

aspects of the environment inside of the gondola so that the pilot can keep awareness about

the conditions inside of the cabin15.

3. The third section of the gondola would contain the fuel pumps and combustion chamber.

15 Jerry Sellers et al., Understanding Space: An Introduction to Astronautics, (New York: McGraw Hill, 2005), 492

Illustration 1: The proposed concept would involve a pressurized gondola that works the same way that a hot air balloon would work, but would carry oxidizer as well as fuel to continue a high altitude burn.

Illustration 2: Cutout illustration of proposed gondola

This experimental design must meet the following criteria for success:

1. The airship MUST pass the stratopause and ascend midways into the mesosphere (about 90 km

or about 56 miles).

2. The engine burn must continue after passing an altitude of 70,000 ft (the altitude aimed for by

Vijaypat Singhania)

3. The ascent must be able to efficiently burn so that the fuel is not completely exhausted after the

airship has flown through the troposphere and atmosphere, where the atmosphere is the thickest

and the airship will encounter the most resistance.

4. The descent must be slow and gentle and use the same method of ascent as a standard thermal

airship or hot air balloon by burning to slow the rate of descent.

Closing Remarks

If a model thermal airship is produced that is capable of meeting mesospheric altitudes, then

commercial spaceflight companies may want to consider using the thermal airship as its mode of providing

suborbital spaceflights at a fraction of a cost. But weather forecasting would also benefit from such an

experiment, as it would allow meteorologists to gain a better understanding of the mesosphere with new

weather ballooning capabilities. This technology could also evolve into hybrid vehicles rocket-airship

vehicles that reduce the cost of getting into orbit.

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Giordano, Nicholas. College Physics. 2 ed. Belmont, CA: Brooks-Cole Pub Co, 2012.

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