All posts by Pete Lobner

A Third Source of Gravitational Waves Appears to Have Been Detected

The US Laser Interferometer Gravitational-Wave Observatory (LIGO) began its third “observing run,” O3, on 1 April 2019 after a series of upgrades were completed on both LIGO instruments (in Hanford, Washington and Livingston, Louisiana) during an 18-month shutdown period after the second observing run, O2, ended on 25 August 2017.  The European Gravitational Observatory’s (EGO) Virgo instrument also joined O3.  Since its last observing run, which coincided with part of LIGO O2, Virgo also received a series of upgrades that have almost doubled its sensitivity.  O3 is scheduled to last for one calendar year.  Check out the details of these gravitational wave instruments and O3 at the following websites:

On 12 August, the LIGO / Virgo team reported:

“By July 31st, 2019, LIGO had sent out 25 alerts to possible detections, three have since been retracted, leaving us with 22 ‘candidate’ gravitational wave events. We call them “candidates” because we still need time to vet all of them. If all candidates are verified, then the number of detections made by LIGO in just the first third of O3 will double the number of detections made in its first two runs combined……So far, no electromagnetic counterparts related to our public alerts have been observed, but all candidates are being actively analyzed by LSC/Virgo science teams.”

As of July 31, 2019 LIGO/Virgo had seen:

  • 18 binary black hole merger candidates
  • 4 binary neutron star merger candidates

The LIGO-Virgo Collaboration has created the Gravitational Wave Candidate Event Database (GraceDB), which members of the public can access to track observations made during O3 here: 

https://gracedb.ligo.org/superevents/public/O3/

On 14 August 2019, the LIGO and Virgo instruments detected a gravitational wave event that appears to have come from a previously undetected source: the collision of a black hole and a neutron star.  This event, tentatively identified as S190814bv, is estimated to have occurred about 900 million light-years away.   Data from the three detectors enabled scientists to locate the source of these gravitational waves to a 23 square degree region of the sky, which would be about seven times the diameter of the Moon as seen from Earth.  While the gravitational wave signal was characterized as “remarkably strong,” so far, there have been no “multi-messenger” detections in the electromagnetic spectrum to help further refine the location and the nature of the event.

You’ll find a description of a black hole collision with a neutron star on the Simulating eXtreme Spacetimes (SXS) website at the following link:

https://www.black-holes.org/the-science-compact-objects/compact-objects/black-holes-and-neutron-stars

Here, SXS offers the following sequence of events for this exotic collision. 

Neutron star beginning to disrupt. The tidal forces of the black hole squeeze the star like a tube of toothpaste. The distance between the neutron star and the black hole is about 50 km, and they are orbiting hundreds of times per second. Source: SXS
Ejected tail flinging off into space. This matter will eventually contribute rare heavy elements to the interstellar medium. Source: SXS
Accretion disk swirling around the black hole. The accretion disk survives outside the black hole for less than a second. But this is enough time to release an enormous amount of energy in the form of neutrinos. It spans a little more than a hundred km from side to side.
Source: SXS

For more information, check the LIGO and Virgo websites for their news updates.

Modern Airships – Part 1

1. Introduction

“Modern Airships” is a three-part document that contains an overview of modern airship technology in Part 1 and links in Parts 1, 2 and 3 to 79 individual articles on historic and advanced airship designs.  This is Part 1.  Here are the links to the other two parts:

You’ll find a consolidated Table of Contents for all three parts at the following link.  This should help you navigate the large volume of material in the three documents.

Modern Airships – Part 1 begins with an overview of modern airship technology, continues with a summary table identifying the airships addressed in this part, and concludes by providing links to 22 individual articles on these airships. A downloadable copy of Part 1 is available here:

If you have any comments or wish to identify errors in this document, please send me an e-mail to:  PL31416@cox.net.

I hope you’ll find the Modern Airships series to be informative, useful, and different from any other single document on this subject.

Best regards,

Peter Lobner

August 2019

2.  Well-established benefits and opportunities, but a risk-averse market

For more than two decades, there has been significant interest in the use of modern lighter-than-air craft and hybrid airships in a variety of military, commercial and other roles, including:

  • Heavy cargo carriers operating point-to-point between manufacturer and end-user, eliminating inter-modal load transfers enroute
  • Heavy cargo carriers serving remote and/or unimproved sites not adequately served by other modes of transportation
  • Disaster relief, particularly in areas not easily accessible by other means
  • Persistent optionally-manned surveillance platforms for maritime surveillance / border patrol / search and rescue
  • Passenger airships
  • Commercial flying cruise liner / flying hotel
  • Airship yacht
  • Personal airship
  • Drone carrier
  • High altitude regional communications node

One of the very significant factors driving interest in modern airships is that they offer the potential to link isolated regions with the rest of the world while doing so in a way that should have lower environmental impacts than other transportation alternatives for those regions. This target market for airships exists in more than two-thirds of the world’s land area where more than half the world’s population live without direct access to paved roads and reliable ground transportation.

This matter is described well in a 21 February 2016 article by Jeanne Marie Laskas, “Helium Dreams – A new generation of airships is born,” which is posted on The New Yorker website at the following link:

https://www.newyorker.com/magazine/2016/02/29/a-new-generation-of-airships-is-born

In spite of the significant interest and the development of many promising airship designs, an actual worldwide airship cargo and passenger transportation industry has been very slow in developing.  To give you an example of how slow:

  • As of August 2019, the Zeppelin NT 07 is the only advanced airship that has been certified and is flying regularly in commercial passenger service. 
  • At the March 2019 Aviation Innovations Conference – Cargo Airshipsin Toronto, Canada, Solar Ship CEO Jay Godsall proposed an industry-wide challenge to actually demonstrate by July 2021 airships that can move a 3 metric ton (6,614 lb) standard 20 foot intermodal container configured as a mobile medical lab 300 km (186 mi) to a remote location. Godsall noted that this capability would be of great value if it did exist, for example, in support of relief efforts in Africa and other regions of the world.

So in spite of the airship industry having developed many designs capable of transporting 10 to 100 tons of cargo thousands of miles, today there is not a single airship than can transport a 3 metric ton (6,614 lb) payload 300 km (186 mi).

Why has the airship industry been so slow to develop? The bottom line has been a persistent lack of funding.  With many manufacturers having invested in developing advanced, detailed designs, the first to secure adequate funding will be able to take the next steps to build a manufacturing facility and a full-scale prototype airship, complete the airship certification process, and start offering a certified airship for sale.

There are a some significant roadblocks in the way:

  • No full-scale prototypes are flying:  The airship firms currently have little more than slide presentations to show to potential investors and customers.  There are few sub-scale airship demonstrators, but no full-scale prototypes.  The airship firms are depending on potential investors and customers making a “leap of faith” that the “paper” airship actually can be delivered.
  • Immature manufacturing capability:  While the airship industry has been good at developing many advanced designs, some existing as construction-ready plans, few airship firms are in the process of building an airship factory. The industrial scale-up factor for an airship firm to go from the design and engineering facilities existing today to the facilities needed for series production of full-scale airships is huge.  Several years ago, Russian airship manufacturer Augur RosAeroSystems proposed building a new factory to manufacture up to 10 ATLANT airships per year.  The funding requirement for that factory was estimated at $157 million.  The exact amount isn’t important.  No matter how you look at it, it’s a big number.  Large investments are needed for any airship firm to become a viable manufacturer.
  • Significant financial risk:The amount of funding needed by airship firms to make the next steps toward becoming a viable manufacturer exceeds the amount available from venture capitalists who are willing to accept significant risk. Private equity sources typically are risk averse. Public sources, or public-private partnerships, have been slow to develop an interest in the airship industry. The French airship firm Flying Whales appears to be the first to have gained access to significant funding from public institutions.  
  • Significant regulatory risk:Current US, Canadian and European airship regulations were developed for non-rigid blimps and they fail to address how to certify most of the advanced airships currently under development.  This means that the first airship manufacturers seeking type certificates for advanced airships will face uphill battles as they have to deal with aviation regulatory authorities struggling to fill in the big gaps in their regulatory framework and set precedents for later applicants.  It is incumbent on the aviation regulatory authorities to get updated regulations in place in a timely manner and make the regulatory process predictable for existing and future applicants.  
  • No airship operational infrastructure:  There is nothing existing today that is intended to support the operation of new commercial airships tomorrow.  The early airship operators will need to develop operating bases, hanger facilities, maintenance facilities, airship routes, and commercial arrangements for cargo and passengers.  While many airship manufacturers boast that their designs can operate from unimproved sites without most or all of the traditional ground infrastructure required by zeppelins and blimps, the fact of the matter is that not all advanced airships will be operating from dirt fields and parked outside when not flying.  There is real infrastructure to be built, and this will require a significant investment by the airship operators.
  • Steep learning curve for potential customers: Only the operators of the Zeppelin NT have experience in operating a modern airship today.  The process for integrating airship operations and maintenance into a customer’s business work flow has more than a few unknowns.  With the lack of modern airship operational experience, there are no testimonials or help lines to support a new customer. They’ll have to work out the details with only limited support.  Ten years from now, the situation should be vastly improved, but for the first operators, it will be a challenge.
  • Few qualified pilots and crew:  The airship manufacturers will need to work with the aviation regulatory authorities and develop programs for training and licensing new pilots and crew.  The British airship manufacturer Varialift has stated that one of the roles of their ARH-PT prototype will be to train future pilots.  

This uncertain business climate for airships seems likely to change in the early 2020s, when several different heavy-lift airships are expected to be certified by airworthiness authorities and ready for series production and sale to interested customers.  If customers step up and place significant orders, we may be able to realize the promise of airship travel and its potential to change our world in many positive ways.

3. Status of current aviation regulations for airships

As noted previously, current aviation regulations have not kept pace with the development of modern airship technology. In this section, we’ll take a look at the current regulations.

In the US, the Federal Aviation Administration’s (FAA) current requirements for airships are defined in the document FAA-P-8110-2, Change 2, “Airship Design Criteria (ADC),” dated 6 February 1995, which is available here:

https://www.faa.gov/aircraft/air_cert/design_approvals/airships/airships_regs/media/aceAirshipDesignCriteria.pdf

The ADC applies to non-rigid, near-equilibrium, conventional airships with seating for nine passengers or less, excluding the pilot, and it serves as the basis for issuing the type certificate required before a particular airship type can enter commercial service in the US.  The limited scope of this current regulation is highlighted by the following definitions contained in the ADC:

  • Airship:  an engine-driven, lighter-than-air aircraft, than can be steered.
  • Non-rigid: an airship whose structural integrity and shape is maintained by the pressure of the gas contained within the envelope.
  • Near-equilibrium: an airship that is capable of achieving zero static heaviness during normal flight operations.

Supplementary guidance for non-rigid, near-equilibrium, conventional airships is provided in FAA Advisory Circular (AC) No. 21.17-1A, “Type Certification – Airships,” dated 25 September 1992, which is available here:

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_21-17-1a.pdf

The FAA’s ADC and the associated AC were written for blimps, not for the range of modern airships under development today.  For example, aerostatic lift is only one component of lift in modern hybrid airships, which also depend on powered lift from engines and aerodynamic lift during forward flight.  Hybrid airships are not “lighter-than-air” and cannot achieve zero static heaviness during normal operations, yet they are an important class of airships being developed in several countries.  In addition, almost all modern airships, except blimps, have rigid or semi-rigid structures that enable them to carry heavy loads and mount powerful engines that cannot possibly be handled by a non-rigid airship.

Recognizing the absence of an adequate regulatory framework for modern airships, civil aviation authorities of Germany and Netherlands developed supplementary guidance to the European Joint Aviation Requirements (JAR-25) and the FAA’s ADC for a category of airships called “Transport Airships,” which they define as follows:

“The transport category is defined for multi-engined propeller driven airships that have a capacity of 20 or more passengers (excluding crew), or a maximum take-off mass of 15,000 kg or more, or a design lifting gas volume of 20,000 m3or more, whichever is greater.”

These supplementary requirements are contained in the document “Transport Airship Requirements” (TAR), dated March 2000, which you will find at the following link:

https://www.faa.gov/aircraft/air_cert/design_approvals/airships/airships_regs/media/aceAirshipTARIssue1.pdf

So, this is the status of US and European airship regulations today.  

In the US, Lockheed-Martin currently is in the process of working with the FAA to get a type certificate for their semi-buoyant, hybrid airship, the LMH-1.  Clearly, they are dealing with great regulatory uncertainty.  Hopefully, the LMH-1 type certification effort will be successful and serve as a precedent for later applicants. 

4. Lifting gas

In the US, Canada and Europe, aviation regulations only allow the use of non-flammable lifting gas:

  • FAA ADC:  “The lifting gas must be non-flammable.” (4.48)
  • TAR: “The lifting gas must be non-flammable, non-toxic and non-irritant” (TAR 893)
  • Canadian Air Regulations:  “Hydrogen is not an acceptable lifting gas for use in airships.” (541.7)

Without hydrogen, the remaining practical choices for lifting gas are  helium and hot air. A given volume of hot air can lift only about one-third as much as the same volume of helium, making helium the near-universal choice, with hot air being relegated to a few, small thermal airships.

The current high price of helium is a factor in the renewed interest in hydrogen as a lifting gas.  It’s also a key selling point for thermal airships.  Most helium is produced as a byproduct from natural gas production. Helium is not “rare.” Only a very small fraction of helium available in natural gas currently is recovered, on the order of 1.25%.  The remainder is released to the atmosphere. The helium recovery rate could be higher, but is not warranted by the current market for helium.  Helium is difficult to store.  The cost of transportation to end-users is a big fraction of the market price of helium.

Hydrogen provides 10% more lift than helium.  It can be manufactured easily at low cost and can be stored.  If needed, hydrogen can be produced with simple equipment in the field.  This could be an important capability for recovering an airship damaged and grounded in a remote region.  One airship concept described in Modern Airships – Part 3, the Aeromodeller II, is designed for using hydrogen as the lifting gas and as a clean fuel (zero greenhouse gases produced) for its propulsion engines.  A unique feature of this airship concept is an on-board system to generate more hydrogen when needed from the electrolysis of water ballast.

A technique for preventing hydrogen flammability is described in Russian patent RU2441685C2, “Gas compound used to prevent inflammation and explosion of hydrogen-air mixtures,” which was submitted in 2010 and posted in 2012. This technique appears to be applicable to an airship using hydrogen as its lifting gas.  You can read the patent at the following link: https://patents.google.com/patent/RU2441685C2/en

The Canadian airship firm Buoyant Aircraft Systems International (BASI) is a proponent of using hydrogen lifting gas.  Anticipating a future opportunity to use hydrogen, they have designed their lifting gas cells to be able to operate with either helium or hydrogen.  BASI claims that lifting gas cells designed originally for helium lifting gas cannot later be used with hydrogen lifting gas.

Regulatory changes will be required to permit the general use of hydrogen lifting gas in commercial airships.  Time will tell if that change ever occurs.

Even with the needed regulatory changes, the insurance industry will have to deal with the matter of insuring a hydrogen-filled airship. 

5.  Types of modern airships

The term “aerostat” broadly includes all lighter than air vehicles that gain lift through the use of a buoyant gas. Aerostats include unpowered balloons (tethered or free-flying) and powered airships. 

The following types of powered airships are described in this section:  

  • Conventional airships
  • Semi-buoyant airships and aircraft
  • Variable buoyancy airships
  • Helistats (airship – helicopter hybrid)  
  • Thermal (hot air) airships

5.1  Conventional airships

Conventional airships are lighter-than-air (LTA) vehicles that operate at or near neutral buoyancy. The lifting gas (helium) generates approximately 100% of the lift at low speed, thereby permitting vertical takeoff and landing (VTOL) operations and hovering with little or no lift contribution from the propulsion / maneuvering system.  Various types of propulsors may be used for cruise flight propulsion and for low-speed maneuvering and station keeping. 

Airships of this type include non-rigid blimps, rigid zeppelins, and semi-rigid airships.

  • Non-rigid airships (blimps): These airships have a flexible envelope that defines the shape of the airship, contains the lifting gas cells and ballonets for buoyancy management, and supports the load of a gondola, engines and payload.
  • Rigid airships (zeppelins):These airships have a lightweight, rigid airframe that defines their exterior shape.  The rigid airframe supports the gondola, engines and payload.  Lifting gas cells and ballonets are located within the rigid airframe.
  • Semi-rigid airships:  These airships have a rigid internal spine or structural framework that supports loads. A flexible envelope is installed over the structural framework and contains the lifting gas cells and ballonets.

The Euro Airship DGPAtt and the Flying Whales LCA60T are examples of rigid conventional airships.

The Zeppelin NT and the SkyLifter are examples of semi-rigid conventional airships.

After being loaded and ballasted before flight, conventional airships have various means to control the in-flight buoyancy of the airship. Control can be exercised over ballast, lifting gas and the ballonets as described below.

Controlling  buoyancy with ballast:  

Many conventional airships require adjustable ballast (i.e., typically water or sand) that can be added or removed as needed to establish a desired net buoyancy before flight.  Load exchanges (i.e., taking on / discharging cargo or passengers) can change the overall mass of an airship and may require a corresponding ballast adjustment. If an airship is heavy and the desired buoyancy can’t be restored with the ballonets or other means, ballast can be removed on the ground or may need to be dumped in flight to increase buoyancy.

Controlling  buoyancy with lifting gas:  

However, temperature differentials between the lifting gas and the ambient air will affect the aerostatic lift produced by the lifting gas.  To exploit this behavior, some airships can control buoyancy using lifting gas heaters / coolers to manage gas temperature.  

The lifting gas inside an airship’s gas cells is at atmospheric pressure.  Normally, there is no significant loss (leakage) of lifting gas to the environment.  A given mass of lifting gas will create a constant lift force, regardless of pressure or altitude, when the lifting gas is at equal pressure and temperature with the surrounding air. Therefore, a change in altitude will not change the aerostatic lift.  

The lifting gas heaters are important for operation in the Arctic, where a cold-soak in nighttime temperatures may result in the lifting gas temperature lagging behind daytime ambient air temperature.  This temperature differential would result in a loss of lift until lifting gas and ambient air temperatures were equal.

Conversely, operating an airship in hot regions can result in the lifting gas temperature rising above ambient air temperature (the lifting gas becomes “superheated”), thereby increasing buoyancy. To restore buoyancy in this case, some airships have coolers (i.e., helium-to-air heat exchangers) in the lifting gas cells to remove heat from the lifting gas.

As described by Boyle’s Law, pressure (P) and gas volume (V) are inversely proportional at a constant temperature according to the following relationship:  PV = K, where K is a constant.  As an airship ascends, atmospheric pressure decreases.  This means that a fixed mass of lifting gas will expand within the lifting gas cells during ascent, and will contract within the lifting gas cells during descent.  As described previously, this lifting gas expansion and contraction does not affect the magnitude of the aerostatic lift as long as the lifting gas is at equal pressure and temperature with the surrounding air.

If an airship is light and the desired buoyancy cannot be restored with the ballonets or lifting gas coolers, it is possible to vent some lifting gas to the atmosphere to decrease aerostatic lift. 

Controlling  buoyancy with ballonets:

The airship hull / envelope is divided into sealed lifting gas volumes and separate gas volumes called “ballonets” that contain ambient air. The ballonets are used to compensate for modest changes in buoyancy by inflating them with small fans or venting them to the atmosphere to change the gross weight of the airship.  Fore and aft ballonets can be operated individually to adjust the trim (pitch angle) of the airship. 

As the airship gains altitude, external air pressure decreases, allowing the helium gas volume to expand within the gas envelope, into space previously occupied by the air in the ballonets, which vent a portion of their air content overboard. The airship reaches its maximum altitude, known as its “pressure height,” when the helium gas volume has expanded to fill the gas envelope and the ballonets are empty.  At this point, the airship’s mass is at a minimum and the helium lifting gas can expand no further.

On the ground, the ballonets may be inflated with air to make the airship negatively buoyant (heavier-than-air) to simplify ground handling. To takeoff, the ballonets would be vented to the atmosphere, reducing the mass of air carried by the airship.

To descend, a low-pressure fan is used to inflate the ballonets with outside air, adding mass. As the airship continues to descend into the denser atmosphere, the helium gas volume continues to contract and the ballonets become proportionately larger, carrying a larger mass of air.  Ballonet inflation / venting is controlled to manage buoyancy as the airship approaches the ground for a landing.

In flight, inflating only the fore or aft ballonet, and allowing the opposite ballonet to deflate, will make the bow or stern of the airship heavier and change the pitch of the airship.  These operating principles are shown in the following diagrams of a blimp with two ballonets, which are shown in blue.

Blimp with ballonets (blue).  Source: zeppelinfan.de

5.2  Semi-buoyant hybrid airships

Hybrid airships are heavier-than-air (HTA) vehicles. The term “semi-buoyant” means that the lifting gas provides only a fraction of the needed lift (typically 60 – 80%) and the balance of the lift needed for flight is generated by other means, such as vectored thrust engines and aerodynamic lift from the fuselage and wings during forward flight.

Sources of lift for a semi-rigid, hybrid airship.  Source: DoD 2012

Basic characteristics of hybrid airships include the following:

  • This type of airship requires some airspeed to generate aerodynamic lift. Therefore, it typically makes a short takeoff and landing (STOL).  
  • Some hybrid airships may be capable of limited VTOL operations (i.e., when lightly loaded, or when equipped with powerful vectored thrust engines).
  • Like conventional airships, the gas envelope in hybrid airship is divided into lifting gas volumes and separate ballonet volumes containing ambient air. 
  • Hybrid airships are heavier-than-air and are easier to control on the ground than conventional airships.

There are two types of hybrid airships:  semi-rigid and rigid.  

  • Semi-rigid hybrid airships:  These airships have a structural keel or spine to carry loads, and a large, lifting-body shaped inflated fuselage containing the lifting gas cells and ballonets.  Operation of the ballonets to adjust net buoyancy and pitch angle is similar to their use on conventional airships.  These wide hybrid airships may have separate ballonets on each side of the inflated envelope that can be used to adjust the roll angle.  While these airships are heavier-than-air, they generally require adjustable ballast to handle a load exchange involving a heavy load.
  • Rigid hybrid airships:  These airships have a more substantial structure that defines the shape of the exterior aeroshell. The “hard” skin of the airship may be better suited for operation in Arctic conditions, where snow loads and high winds might challenge the integrity of an inflated fuselage of a semi-rigid airship. Otherwise, the rigid hybrid airship behavior is similar to a semi-rigid airship. 

The Lockheed-Martin LMH-1 is an example of a semi-rigid hybrid airship.  The AeroTruck being developed by Russian firm Airship GP is an example of a rigid hybrid airship.

5.3  Semi-buoyant aircraft

Semi-buoyant aircraft are heavier-than-air, rigid, winged aircraft that carry a large helium volume to significantly reduce the weight of the aircraft and improve its load-carrying capability.  Aerostatic lift provides a smaller fraction of total lift for a semi-buoyant aircraft, like a Dynalifter, than it does for a semi-buoyant, hybrid airship.

A semi-buoyant aircraft behaves much like a conventional aircraft in the air and on the ground, and is less affected by wind gusts and changing wind direction on the ground than a hybrid airship.

The semi-buoyant aircraft has some flexibility for loading and discharging cargo without having to be immediately concerned about exchanging ballast, except in windy conditions.

The Aereon Corporation’s Dynairship and the Ohio Airships Dynalifter are examples of semi-buoyant aircraft.

5.4  Variable buoyancy airships

Variable buoyancy airships are rigid airships that can change their net lift, or “static heaviness,” to become LTA or HTA as the circumstances require.  Basic characteristics of variable buoyancy airships include the following:

  • Variable buoyancy airships are capable of VTOL operations and hovering, usually with a full load.
  • The buoyancy control system may enable in-flight load exchanges from a hovering airship without the need for external ballast.
  • On the ground, variable buoyancy airships can make themselves heavier-than-air to facilitate load exchanges without the need for external infrastructure or ballast.
  • It is not necessary for a “light” airship to vent the lifting gas to the atmosphere.

Variable buoyancy / fixed volume airships

Variable buoyancy commonly is implemented by adjusting the net lift of a fixed volume airship.  For example, a variable buoyancy / fixed volume airship can become heavier by compressing the helium lifting gas or ambient air:

  • Compressing some of the helium lifting gas into smaller volume tanks aboard the airship reduces the total mass of helium available to generate aerostatic lift.
  • Compressing ambient air into pressurized tanks aboard the airship adds mass (ballast) to the airship and thus decreases the net lift.

The airship becomes lighter by venting the pressurized tanks:

  • Compressed helium lifting gas is vented back into the helium lift cells, increasing the mass of helium available to generate aerostatic lift.
  • Compressed air is vented to the atmosphere, reducing the mass of the airship and thus increasing net lift.

The Aeros Aeroscraft Dragon Dreamand the Varilift ARH-50 are examples of variable buoyancy / fixed volume airships.

Variable buoyancy / variable volume airships

Variable buoyancy also can be implemented by adjusting the total  volume of the helium envelope without changing the mass of helium in the envelope. 

  • As the size of the helium envelope increases, the airship displaces more air and the buoyant force of the atmosphere acting on the airship increases. Static heaviness decreases.
  • Likewise, as the size of the helium envelope decreases, the airship displaces less air and the buoyant force of the atmosphere acting on the airship decreases. Static heaviness increases.

The EADS Tropospheric Airship is an example of a variable buoyancy / variable volume airship.

5.5 Helistats (airship / helicopter hybrid)

There have been many different designs of airship / helicopter hybrid aircraft (a helistat) in which the airship part of the hybrid aircraft carries the weight of the aircraft itself and helicopter rotors deployed around the base of the airship work in concert to propel the aircraft and to lift and deliver heavy payloads without the need for an exchange of ballast.

The Piasecki PA-97 and the Boeing  / Skyhook International SkyHook JLH-40 are examples of helistats.

5.5 Thermal (hot air) airships

Thermal airships use hot air as the lifting gas in place of helium or hydrogen. A given volume of hot air can lift only about one-third as much as the same volume of helium.  Therefore, the gas envelope on a thermal airship is proportionally larger than it would be on a comparable airship using helium as the lifting gas. 

The non-rigid GEFA-Flug four-seat AS-105GD/4 and six-seat AS-105GD/6 and the semi-rigid, two-seat Skyacht Personal Blimp are examples of current thermal airships that use propane burners to produce the hot air for lift.  Pitch can be controlled with fore and aft burners.  There are no ballonets.

6. How does an airship pick up and deliver a heavy load? 

The term “load exchange” refers to the pickup and delivery of cargo by an airship, with or without an exchange of external ballast to compensate for the mass of cargo being moved on or off the airship.  This isn’t a simple problem to solve.

The problem of buoyancy control

In Marie Laskas’ article, Boris Pasternak, CEO of airship manufacturer Worldwide Aeros Corp. (Aeros), commented on the common problem facing all airships when a heavy load is delivered:

“The biggest challenge in using lighter-than-air technology to lift hundreds of tons of cargo is not with the lifting itself—the larger the envelope of gas, the more you can lift—but with what occurs after you let the stuff go. ‘When I drop the cargo, what happens to the airship?’ Pasternak said. ‘It’s flying to the moon.’ An airship must take on ballast to compensate for the lost weight of the unloaded cargo, or a ground crew must hold it down with ropes.”

Among the many current designers and manufacturers of large airships, the matter of maintaining the airship’s net buoyancy within certain limits while loading and unloading cargo and passengers is handled in several different ways depending on the type of airship involved.  Some load exchange solutions require ground infrastructure for external ballast handling, while others require no external ballasting infrastructure and instead use systems aboard the airship to adjust buoyancy to match current needs or provide vectored thrust (or suction) to temporarily counteract the excess buoyancy.  The solution chosen for managing airship buoyancy during a load exchange strongly influences how an airship can be operationally employed and where it can pickup and deliver its payload.

Additional problems for airborne load exchanges

Several current designers and manufacturers of large airships report that their airships will have the ability to conduct airborne load exchanges of cargo from a hovering airship.  Jeremy Fitton, the Director of SkyLifter, Ltd., described the key issues affecting a precision load exchange executed by a hovering airship as follows:

“The buoyancy management element of (an airborne) load-exchange is not the main control problem for airships. Keeping the aircraft in a geo-stationary position – in relation to the payload on the ground – is the main problem, of which buoyancy is a component.”

The matters of precisely maintaining the airship’s geo-stationary position throughout an airborne load exchange and controlling the heading of the airship and the suspended load are handled in different ways depending on the type of airship involved.  The time required to accomplish the airborne load exchange can be many minutes or much longer, depending on the weight of the cargo being picked up or delivered and the time it takes for the airship to adjust its buoyancy for its new loaded or unloaded condition. Most of the airships offering an airborne load exchange capability are asymmetrical (i.e., conventional “cigar shaped” or hybrid aerobody-shaped) and must point their nose into the wind during an airborne load exchange.  Their asymmetrical shape makes these airships vulnerable to wind shifts during the load exchange. The changing cross-sectional area exposed to the wind complicates the matter of maintaining a precise geo-position with an array of vectoring thrusters. 

During such a delivery in variable winds, even with precise geo-positioning over the destination, the variable wind direction may require the hovering airship to change its heading slightly to point into the wind. This can create a significant hazard on the ground, especially when long items, such as a wind turbine blade or long pipe segment are being delivered.  For example, the longest wind turbine blade currently in production is the GE Haliade-X intended for off-shore wind turbine installations.  This one-piece blade is 107 meter (351 ft) long.  A two degree change in airship heading could sweep the long end of the blade more than three meters (10 feet), which could be hazardous to people and structures on the ground.

Regulatory requirements pertaining to load exchanges

The German / Netherlands “Transport Airship Requirements” (TAR), includes the following requirement for load exchanges in TAR 80, “Loading / Unloading”:

(c) During any cargo exchange…the airship must be capable of achieving a safe free flight condition within a time period short enough to recover from a potentially hazardous condition.”

This requirement will be a particular challenge for airships designed to execute an airborne load exchange from a hovering airship.

The CargoLifter approach to an airborne load exchange

One early approach for delivering a load from a hovering airship was developed for the CargoLifter CL160.  As described on the Aviation Technology website (https://www.aerospace-technology.com/projects/cargolifter/), the CL160 would have performed an in-flight delivery of cargo as follows:

“The airship hovers at about 100 m above the ground and a special loading frame, which is fixed during flight to the keel of the airship, is then rigged with four cable winches to the ground, a procedure which is to assure that the airship’s lifting gear stays exactly above the desired position. Ballast water is then pumped into tanks on the frame and the payload can be unloaded. The anchor lines are released and the frame is pulled back into the payload bay of the airship.”In a 2002 test using a heavy-lift CargoLifter CL75 aerostat as an airship surrogate, a 55 metric ton German mine-clearing tank was loaded, lifted and discharged from the loading frame as water ballast was unloaded and later reloaded in approximately the same time it took to secure the tank in the carriage (several minutes).  In this test, the 55 metric tons cargo was exchanged with about 55 cubic meters (1,766 cubic feet, 14,530 US gallons) of water ballast.

The SkyLifter approach to an airborne load exchange

One airship design, the SkyLifter, addresses the airborne load exchange issues with a symmetrical, disc-shaped hull that presents the same effective cross-sectional area to a wind coming from any direction. This airship is designed to move equally well in any direction (omni-directional), simplifying airship controls in changing wind conditions, and likely giving the SkyLifter an advantage over other designs in conducting a precision airborne load exchange.

You’ll find more information on airship load exchange issues in a December 2017 paper by Charles Luffman, entitled, “A Dissertation on Buoyancy and Load Exchange for Heavy Airships (Rev. B)”, which is available at the following link:  

https://www.luffships.com/wp-content/uploads/2018/02/buoyancy_and_load_exchange.pdf

7. The scale of large cargo airships

Some of the advanced airship concepts being developed, especially for future heavy-lift cargo carriers, will result in extremely large air vehicles on a scale not seen since the heyday of the giant zeppelins in the 1930s.  Consider the following semi-rigid hybrid airships shown to scale with contemporary fixed-wing cargo aircraft.

Size comparison for hybrid airships sized for various lift applications.  
Source: DoD 2012

8. Specific airships in Part 1

The airships reviewed in Part 1 are summarized in the following set of tables, which include many heavy-lift cargo airships. In addition, there are several examples of semi-buoyant aircraft, helistats and thermal (hot air) airships.  Links to the 22 individual articles on these airships are provided at the end of this document.

The CargoLifter CL160, helistats, Megalifter, Aereon Dynairship and Project Walrus are included because they are of historical interest as early, though unsuccessful, attempts to develop large cargo airships. Concepts and technologies developed on these airship projects have promoted the development of other modern airships.

Among the airships in the above tables, the following have flown:  

  • Zeppelin NT 07 
  • Skybus 80K
  • Aeros Aeroscraft Dragon Dream
  • Piasecki PA-97
  • Dynalifter DL-100
  • Aereon 26
  • ATG / SkyCat Group SkyKitten
  • Hybrid Air Vehicles HAV-3 & HAV-304
  • Hybrid Air Vehicles Airlander 10
  • Lockheed Martin P-791
  • Volaris 901 & 902
  • GEFA-Flug AS-105GD/4 & AS-105GD/6 
  • Skyacht Personal Blimp

As of August 2019, the Zeppelin NT 07 is the only advanced airship that has been certified and is flying regularly in commercial passenger service.  The simpler GEFA-Flug and Skyacht thermal (hot air) airships also are flying regularly. The others that have flown have been retired.  The remaining airships in the Part 1 tables are under development or remain as concepts only. 

Among the airships in the above tables, several cargo airships are likely to receive their airworthiness certification in the next several years. The leading candidates identified in Part 1 are:

  • Lockheed Martin: LMH-1 hybrid airship
  • Hybrid Air Vehicles (HAV): Airlander 10 hybrid airship
  • Aeros Aeroscraft: ML866 / Aeroscraft Gen 2 variable buoyancy airship
  • Volaris: V932 NATAC semi-buoyant airship

These airships will be competing in the worldwide airship market with the leading candidates identified in Part 2, which may enter the market in the same time frame:

  • Flying Whales: LCA60T rigid airship
  • Varialift:  ARH-PT variable buoyancy airship prototype and the larger ARH 50
  • Euro Airship:  Corsair & DGPAtt variable buoyancy airships
  • Solar Ship: 24-meter Caracal light cargo semi-buoyant airship and the Wolverine medium cargo semi-buoyant aircraft
  • Egan Airships:  The PLIMP drone and Model J plane / blimp hybrids

All of these candidates depend on a source of funding to bring their designs to market. 

The early 2020s will be an exciting time for the airship industry.  We’ll finally get to see if the availability of several different heavy-lift airships with commercial airworthiness certificates will be enough to open a new era in airship transportation. Aviation regulatory agencies need to help reduce risk by eliminating regulatory uncertainty and putting in place an adequate regulatory framework for the wide variety of advanced airships being developed. Customers with business cases for airship applications need to step up, place firm orders, and then begin the pioneering task of employing their airships and building a worldwide airship transportation network with associated ground infrastructure.

9. Links to the individual articles

The following links will take you to the 22 individual Modern Airships – Part 1 articles.  Note that the following articles address more than one airship that appeared in the preceding graphic tables:  Aereon, Aeros, Helistats, Hybrid Air Vehicles, Ohio Airships and Voliris.

Conventional airships:

Variable buoyancy, fixed volume airships:

Helistats (airship / helicopter hybrid):

Hybrid, semi-buoyant aircraft:

Hybrid, semi-buoyant airships:

Thermal (hot air) airships:

Modern Airships – Part 3

1. Introduction

“Modern Airships” is a three-part document that contains an overview of modern airship technology in Part 1 and links in Parts 1, 2 and 3 to 79 individual articles on historic and advanced airship designs. This is Part 3.  Here are the links to the other two parts:

You’ll find a consolidated Table of Contents for all three parts at the following link.  This should help you navigate the large volume of material in the three documents.

Modern Airships – Part 3 begins with a summary table identifying the airship concepts addressed in this part, and concludes by providing links to 32 individual articles on these airship concepts. A downloadable copy of Part 3 is available here:

If you have any comments or wish to identify errors in this document, please send me an e-mail to:  PL31416@cox.net.

I hope you’ll find the Modern Airships series to be informative, useful, and different from any other single document on this subject.

Best regards,

Peter Lobner

August 2019

2. Specific airship concepts in Part 3

The airships described in Part 3 are relatively exotic concepts in comparison to the heavy-lift cargo airships that dominate Parts 1 and 2.  Many of the airship concepts in Part 3 are designed for operation with very low or no carbon emissions.  I’ve grouped these airship concepts based on their applications rather than on their design / type because sometimes those details are difficult to determine when few graphics and limited descriptions are available.  A few of these airships look good as concepts, but may be impossible to build.  Nonetheless, all of these relatively exotic concepts point toward an airship future that will benefit from the great creativity expressed by these designers.

The airship design concepts reviewed in Part 3 are summarized in the following set of tables.  Except for a few sub-scale models, none of these airship concepts have flown.  Links to individual articles on these airships are provided at the end of this document.

3. Links to the individual articles

The following links will take you to 32 individual articles.  Note that the Avalon Airships article addresses all three of their airship design concepts, which are listed separately in the above tables and in the following index.

Cargo & multi-purpose airships

Mass transportation airships:

Flying hotel airships:

Touring airships:

Flying yacht airships:

Remotely-piloted special purpose airship:

Personal airships:

Thermal (hot air) airships:

Other novel designs:

Modern Airships – Part 2

1. Introduction

“Modern Airships” is a three-part document that contains an overview of modern airship technology in Part 1 and links in Parts 1, 2 and 3 to 79 individual articles on historic and advanced airship designs. This is Part 2.  Here are the links to the other two parts:

You’ll find a consolidated Table of Contents for all three parts at the following link.  This should help you navigate the large volume of material in the three documents.

Modern Airships – Part 2 begins with a summary table identifying the airship concepts addressed in this part, and concludes by providing links to 25 individual articles on these airship concepts. A downloadable copy of Part 2 is available here:

The links to the individual articles are at the end of this document.

If you have any comments or wish to identify errors in this document, please send me an e-mail to:  PL31416@cox.net.

I hope you’ll find the Modern Airships series to be informative, useful, and different from any other single document on this subject.

Best regards,

Peter Lobner

August 2019

2. Specific airships in Part 2

The airships reviewed in Part 2 are summarized in the following set of tables.  There are many heavy-lift cargo airships in these tables. In addition, there are several solar-powered airships and sub-scale airships that demonstrated novel means of airship propulsion.  Links to the individual articles on these airships are provided at the end of this document.

Among the airships in the above tables, the following full-scale airships have flown:

  • Project Sol’R Nephelios solar-powered airship
  • Solar Ship 20-meter Caracal prototype
  • Solomon Andrews’ Aereon I and II variable buoyancy propulsion airships (in the 1860s)

In addition, the following sub-scale demonstrators have flown:

  • Festo b-IONIC Airfish (demonstration of ionic propulsion)
  • Phoenix and AHAB (demonstrations of variable buoyancy propulsion)

Among the airships in the above tables, several airships are likely to receive their airworthiness certification in the next several years. The leading candidates identified in Part 2 are:

  • Flying Whales: The LCA60T prototype maiden flight is expected to take place in 2021, and the firm appears to have the funding needed to enter full-scale production.
  • Varialift:  The ARH-PT prototype’s first “float test” is expected in 2019.  The first ARH 50 roll out is expected in 2021, with a 24-month certification process before commercial deliveries begin.
  • Euro Airship: Production-ready drawings exist for the Corsair and the larger DGPAtt.  When funding becomes available, they’re ready to go.
  • Solar Ship: The 24-meter Caracal semi-buoyant, inflated wing airship and the larger Wolverine semi-buoyant aircraft are expected to receive Canadian certification, possibly by 2020 – 2021.
  • Egan Airships:  The PLIMP drone and Model J plane / blimp hybrids that have started their FAA certification processes.

These airships will be competing in the worldwide airship market with the leading candidates identified in Part 1, which may enter the market in the same time frame:

  • Lockheed Martin: LMH-1 hybrid airship
  • Hybrid Air Vehicles (HAV): Airlander 10 hybrid airship
  • Aeros Aeroscraft ML866 / Aeroscraft Gen 2: variable buoyancy airship
  • Volaris V932 NATAC: semi-buoyant, inflated wing airship

The early 2020s will be an exciting time for the airship industry.  We’ll finally get to see if the availability of several different heavy-lift airships with commercial airworthiness certificates will be enough to open a new era in airship transportation. Aviation regulatory agencies need to help reduce risk by eliminating regulatory uncertainty and putting in place an adequate regulatory framework for the wide variety of advanced airships being developed. Customers with business cases for airship applications need to step up, place firm orders, and then begin the pioneering task of employing their airships and building a worldwide airship transportation network with associated ground infrastructure.

3. Links to the individual articles

The following links will take you to the 25 individual articles.  Note that the Atlas / Augur RosAeroSystems, Solar Ship, Egan Airships, and variable buoyancy propulsion articles addressed all of the related airship designs, some of which were listed separately in the preceding tables.

Conventional airships:

Variable buoyancy, fixed volume airships:

Variable buoyancy, variable volume airships:

Hybrid, semi-buoyant airships:

Hybrid, solar-powered airships

Plane / blimp hybrids:

Solid-state propulsion airship:

Variable buoyancy propulsion airships:

The Science Behind ATOMIK Vodka

Source:  The Chernobyl Spirit Company

This is a radioactivity-free vodka produced by The Chernobyl Spirit Company from grain and water in Chernobyl’s abandoned zone. The website for ATOMIK vodka is at the following link: https://www.atomikvodka.com

While this product has been widely reported in that past few days, the website offers the following notice:

“WARNING: Sorry, but we’ve only got one experimental bottle of ATOMIK so far, so we can’t sell you anything yet. But if you want to find out more about what we’re trying to do please carry on reading.”

The website is quite interesting and I encourage you to take the time to visit the site.  Following is a summary of some key points from the website and a supporting technical paper.

Background

The members of the ATOMIK vodka technical team are: 

  • Jim Smith, Professor of Environmental Science at Portsmouth University, UK
  • Gennady Laptev, Head of the Radiometric Laboratory at the Ukrainian Hydrometeorological Institute
  • Kyrylo Korychensky, a geologist and radiochemist currently completing his PhD at the Ukrainian Hydrometeorological Institute. Kyrylo’s family has long experience of distillation and he is the Master Distiller of ATOMIK grain spirit.

The team explained their basis for creating ATOMIK vodka. 

“Our group of Ukrainian and UK scientists has been studying the transfer of radioactivity to crops both in the main Exclusion Zone (CEZ) and in the Narodychi District within the Zone of Obligatory Resettlement, where land can’t officially be used for agriculture, but people still live.​

The research shows that in many areas land could now be used to produce crops, which are safe to eat. As every chemist knows, distillation of fermented grain leaves many heavier elements in the waste product so the distillate alcohol is more radioactively “pure” than the original grain. We have used distillation to reduce radioactivity in the grain even further to make a product from Chernobyl which we hope people will want to consume.”

The ATOMIK vodka product

The ATOMIK website contains the following description of the product.

“ATOMIK is a grain spirit (or “moonshine”), a homemade vodka made by people in villages all over Ukraine, Belarus, Poland and Russia since about the twelfth century. 

Grain spirit has more flavour compounds than vodka – by double-distilling and filtering, we are trying to produce a grain spirit which keeps the flavour and character of homemade vodka (“samogon”) but isn’t quite as rough around the edges. We dilute our distillate with a mineral water from the deep aquifer  below the town of Chernobyl about 10 km south of the nuclear power station. It is pure and of high quality, having characteristics of a typical limestone aquifer such as that found in the South of England or the Champagne region of France. We’re currently trying to work out exactly how many thousands of years old this water is but it definitely wasn’t anywhere near the surface in 1986.”

The distillate alcohol experiment

On the Atomic vodka website, the technical team reported on their radiochemical analysis of ATOMIK:

“We have been doing studies to see how much radioactivity transfers from soil to crops in the Chernobyl abandoned areas more than 30 years after the accident. We found that, at our site in the main exclusion zone, radiocaesium in rye was below the (quite cautious) Ukrainian limit but that radiostrontium was a bit above the limit. But when we made ATOMIK grain spirit from the grain, we could find no Chernobyl-derived radioactivity in the distilled alcohol.

The water used to dilute the distillate to 40% alcohol is a mineral water from the deep aquifer  below the town of Chernobyl about 10 km south of the nuclear power station​

The laboratories of The Ukrainian Hydrometeorological Institute and the University of Southampton GAU-Radioanalytical could find no trace of Chernobyl radioactivity in ATOMIK grain spirit. Out of scientific curiosity we’re going to try even more sensitive analytical methods to see if we can find something – nothing on Earth is completely free of radioactivity.”

The August 2019 technical report, “Distillate ethanol production for re-use of abandoned lands – an analysis and risk assessment,” by Jim Smith, Gennady Laptev, et al., shows the location of the experimental plot for ATOMIK grain harvesting relative to the areas around the Chernobyl site that were contaminated by Cs-137.  The site is in an area that received a relatively low level of Cs-137 contamination.

Source: J. Smith, G. Laptev, et al., 2019

This report summarizes the results of the analysis as follows:

  • The rye grain had elevated levels of Cs-137 and Sr-90, but Pu and Am isotopes were below detection limits. The Sr-90 activity was slightly above the Ukrainian limit of 20 Bq kg-1.
  • There were no artificial radionuclides observed in the distillate ethanol (diluted to 40% with Chernobyl Town groundwater) sample. 
  • The low energy beta analysis recorded an estimated 58 Bq/L, which we attribute to natural C-14 consistent with the expected activity concentration of natural C-14 in ethanol at this dilution.

It seems that ATOMIK is as safe to drink as any comparable grain spirit.

You can read the complete paper here: https://www.researchgate.net/publication/334988042_Distillate_ethanol_production_for_re-use_of_abandoned_lands_-_an_analysis_and_risk_assessment

When The Chernobyl Spirit Companyis able to offer ATOMIK for sale, a key market will be the increasing number of tourists who now visit the Chernobyl exclusion zone.  The Chernobyl Spirit Companyhas stated that at least 75% of profits from sales of ATOMIK will go to supporting communities in the affected areas and wildlife conservation.

While you can use the toast ‘na zdorovya’ in Ukraine, a more traditional Ukrainian toast is ‘budmo’ (cheers). When you hear the toast ‘budmo,’ reply back with a hearty ‘hey’! Keep that toast and reply cycle going and the evening will go by very quickly.

Best wishes for success to the The Chernobyl Spirit Company. I’m looking forward the day when I can get a bottle of ATOMIK at my local liquor store.

Now We Know: The Gestation Period of a Southern White Rhino is 493 days

In my 21 May 2018 post, I reported on the pregnancy of the San Diego Zoo’s southern white rhino Victoria. The pregnancy was the result of artificial insemination on 22 March 2018 using the semen from another southern white rhino.  This was the first time that San Diego Zoo Global’s Rhino Rescue Center had been successful in initiating a southern white rhino pregnancy through artificial insemination.

The healthy baby was born on 28 July 2019 after a gestation period of 493 days.

Victoria and baby. Source: San Diego Zoo Global

You can watch a short video of Victoria, the new baby, and San Diego Zoo Global’s Dr. Barbara Durrant here:

You may recall Dr. Barbara Durrant’s 21 June 2017 presentation to the Lyncean Group (Meeting # 112), “Endangered Species Rescue: How far should we go?”   In this presentation, Dr. Durrant explained the complex process being developed at San Diego Zoo Global to use northern white rhino tissue to create artificial embryonic stem cells that can be matured into northern white rhino egg and sperm cells.  You can see her 2017 presentation here:

https://lynceans.org/112-62117/

There are only two northern white rhinos still alive in the whole world. Both are female and beyond breeding age.  San Diego Zoo Global’s Rhino Rescue Centeris part of a team that is working to develop artificial insemination and embryo implantation techniques so they can reliably inseminate a northern white embryo into a southern white rhino female.  This first successful birth of a southern white rhino as a result of artificial insemination is a key milestone in the process of saving the northern white rhino from extinction.

Congratulations to the team at San Diego Zoo Global’s Rhino Rescue Center and to Victoria for this important and happy milestone.

A Look at the Declining US Coal Production and Coal-fired Power Generating Industries

US coal production was strong from the 1990s until 2014, with coal production each year being near or above 1 billion short tons (a “short ton” is 2,000 pounds). The highest annual level of production was achieved in 2008: 1.17 billion short tons. Since then, the coal industry has seen a steady decline in production, and trends indicate that the decline will continue.

In their 10 July 2019 report, “Almost all US coal production is consumed by electric power,” the US Energy Information Administration (EIA) reported that coal is still one of the main sources of energy in the US, accounting for 16% of the nation’s primary energy production in 2018. Nearly all of the coal consumed in the US is produced domestically, and most is consumed by the electric power sector to generate electricity, while some is exported.  The following EIA “coal flow” diagram shows where the coal comes from and (approximately) how it was consumed in 2018.  Total production was about 755 million short tons.  The electric power sector consumed about 84% of production, with only modest amounts being consumed by the industrial sector or exported.

You’ll find this EIA report here: https://www.eia.gov/todayinenergy/detail.php?id=39792

Electricity generation from coal has been on the decline in the US for almost two decades. On 26 June 2019, EIA reported that US electricity generation from renewables surpasses coal in April 2019. In the following EIA chart, you can see the long-term increase in generation from renewables, which contrasts sharply with the long-term decline of generation from coal due to the decommissioning of many coal-fired power plan and the commissioning of no plants since about 2014.

You can read this EIA announcement here:  https://www.eia.gov/todayinenergy/detail.php?id=39992

Between 2010 and the first quarter of 2019, US power companies announced the retirement of more than 546 coal-fired power units, totaling about 102 gigawatts (GW) of generating capacity. Plant owners intend to retire another 17 GW of coal-fired capacity by 2025.  You’ll find the EIA’s 26 July 2019 report on decommissioning US coal-fired power plants here:  https://www.eia.gov/todayinenergy/detail.php?id=40212

In April 2017, EIA reported that on the age of the US coal-fired generating plant fleet. The following chart shows the distribution of coal-fired plants based on their initial operating year.  EIA reported a fleet average age of 39 years in 2017.

You’ll find this EIA report here: https://www.eia.gov/todayinenergy/detail.php?id=30812

The following table lists EIA data on the numbers of different types of generating plants in the US between 2007 and 2017.  In 2007, the US had 606 coal-fired generating plants.  By the end of 2017, that number had dropped to 359.

You’ll find the EIA data here: https://www.eia.gov/electricity/annual/html/epa_04_01.html

In another decade, coal-fired generation will be only a small part of the US electric power generation portfolio and the average fleet age will be about 50 years old.  

NOAA’s Monthly Climate Summaries are Worth Your Attention

The National Oceanic and Atmospheric Administration’s (NOAA’s) National Centers for Environmental Information (NCEI) are responsible for “preserving, monitoring, assessing, and providing public access to the Nation’s treasure of climate and historical weather data and information.”  The main NOAA / NCEI website is here:

https://www.ncdc.noaa.gov

The “State of the Climate” is a collection of monthly summaries recapping climate-related occurrences on both a global and national scale.  Your starting point for accessing this collection is here:

https://www.ncdc.noaa.gov/sotc/

The following monthly summaries are available.

I’d like to direct your attention to two particularly impressive monthly summaries:

  • Global Summary Information, which provides a comprehensive top-level view, including the Sea Ice Index
  • Global Climate Report, which provides more information on temperature and precipitation, but excludes the Sea Ice Index information

Here are some of the graphics from the Global Climate Report for June 2019.

Source: NOAA NCEI
Source: NOAA NCEI

NOAA offered the following synopsis of the global climate for June 2019.

  • The month of June was characterized by warmer-than-average temperatures across much of the world. The most notable warm June 2019 temperature departures from average were observed across central and eastern Europe, northern Russia, northeastern Canada, and southern parts of South America.
  • Averaged as a whole, the June 2019 global land and ocean temperature departure from average was the highest for June since global records began in 1880.
  • Nine of the 10 warmest Junes have occurred since 2010.

For more details, see the online June 2019 Global Climate Reportat the following link:

https://www.ncdc.noaa.gov/sotc/global/201906

A complementary NOAA climate data resource is the National Snow & Ice Data Center’s (NSIDC’s) Sea Ice Index, which provides monthly and daily quick looks at Arctic-wide and Antarctic-wide changes in sea ice. It is a source for consistently processed ice extent and concentration images and data values since 1979. Maps show sea ice extent with an outline of the 30-year (1981-2010) median extent for the corresponding month or day. Other maps show sea ice concentration and anomalies and trends in concentration.  In addition, there are several tools you can use on this website to animate a series of monthly images or to compare anomalies or trends.  You’ll find the Sea Ice Index here:

https://nsidc.org/data/seaice_index/

The Arctic sea ice extent for June 2019 and the latest daily results for 23 July 2019 are shown in the following graphics, which show the rapid shrinkage of the ice pack during the Arctic summer.  NOAA reported that the June 2019 Arctic sea ice extent was 10.5% below the 30-year (1981 – 2010) average.  This is the second smallest June Arctic sea ice extent since satellite records began in 1979.

Source:  NOAA NSIDC
Source:  NOAA NSIDC

The monthly Antarctic results for June 2019 and the latest daily results for 23 July 2019 are shown in the following graphics, which show the growth of the Antarctic ice pack during the southern winter season. NOAA reported that the June 2019 Antarctic sea ice extent was 8.5% below the 30-year (1981 – 2010) average.  This is the smallest June Antarctic sea ice extent on record.

Source:  NOAA NSIDC
Source:  NOAA NSIDC

I hope you enjoy exploring NOAA’s “State of the Climate” collection of monthly summaries.

50th Anniversary of the First Manned Moon Landing and a Very Long Time Since the Last Manned Moon Landing

On July 16th, 1969, 13:32:00 UTC, the Saturn V launch vehicle, SA-506, lifted off from Launch Pad 39-A at Kennedy Space Center, Florida on the Apollo 11 mission with astronauts Neil Armstrong (Mission commander), Michael Collins (Command Module pilot) and Edwin (Buzz) Aldrin (Lunar Module pilot).

L to R:  Neil Armstrong, Michael Collins & Buzz Aldrin.  
Source: NASA
Apollo 11 insignia: Eagle with wings outstretched holding 
an olive branch above the Moon with Earth in the background. Source: NASA via Wikipedia

The Apollo spacecraft consisted of three modules: 

  • The three-person Command Module (CM), named Columbia, was the living quarters for the three-person crew during most of the lunar landing mission.
  • The Service Module (SM) contained the propulsion system, electrical fuel cells, consumables storage tanks (oxygen, hydrogen) and various service / support systems. 
  • The two-person, two-stage Lunar Module (LM), named Eagle, would make the Moon landing with two astronauts and return them to the CM.  

The LM’s descent stage (bottom part of the LM with the landing legs) remained on the lunar surface and served as the launch pad for the ascent stage (upper part of the LM with the crew compartment).  Only the 4.9 ton CM was designed to withstand Earth reentry conditions and return the astronauts safely to Earth.

General configuration of the Apollo spacecraft.  The “CSM” is the combined Command Module and Service Module.  Source:  NASA

From its initial low Earth parking orbit, Apollo 11 flew a direct trans-lunar trajectory to the Moon, inserting into lunar orbit about 76 hours after liftoff.  The Apollo 11 mission profile to and from the Moon is shown in the following diagram, and is described in detail here: https://www.mpoweruk.com/Apollo_Moon_Shot.htm

Source:  NASA

Neil Armstrong and Buzz Aldrin landed the Eagle LM in the Sea of Tranquility on 20 July 1969, at 20:17 UTC (about 103 hours elapsed time since launch), while Michael Collins remained in a near-circular lunar orbit aboard the CSM.  Neil Armstrong characterized the lunar surface at the Tranquility Base landing site with the observation, “it has a stark beauty all its own.”

In the two and a half hours they spent on the lunar surface, Armstrong and Aldrin collected 21.55 kg (47.51 lb) of rock samples, took photographs and set up the Passive Seismic Experiment Package (PSEP) and the Laser Ranging RetroReflector (LRRR), which would be left behind on the Moon. The PSEP provided the first lunar seismic data, returning data for three weeks after the astronauts left, and the LRRR allows precise distance measurements to be collected to this day.  Neil Armstrong made an unscheduled jaunt to Little West crater, about 50 m (164 feet) east of the LM, and provided the first view into a lunar crater.

Apollo 11 PSEP in the foreground with astronaut Buzz Aldrin and the LRRR behind it, then the Eagle LM, the American flag, and the TV camera on the left horizon
beyond the American flag.  Source: NASA
Neil Armstrong’s photo showing the Eagle LM from Little West crater
(33 meters in diameter). Source: NASA
Apollo 11 landing site captured from 24 km (15 miles) above the surface
by NASA’s Lunar Reconnaissance Orbiter (LRO).
Source: adapted from NASA Goddard/Arizona State University
Apollo 11 “traverse” map.  
Source: NASA via Smithsonian https://airandspace.si.edu/

Armstrong and Aldrin departed the Moon on 21 July 1969 at 17:54 UTC in the ascent stage of the Eagle LM and then rendezvoused and docked with Collins in the CSM about 3-1/2 hours later. 

LM Eagle ascent stage with Armstrong and Aldrin approaching the CSM Columbia piloted by Collins.  Source: NASA

After discarding the ascent stage, the CSM main engine was fired and Apollo 11 left lunar orbit on 22 July 1969 at 04:55:42 UTC and began its trans-Earth trajectory.  As the Apollo spacecraft approached Earth, the SM was jettisoned. 

The CM reentered the Earth’s atmosphere and landed in the North Pacific on 24 July 1969 at 16:50:35 UTC.  The astronauts and the Apollo 11 spacecraft were recovered by the aircraft carrier USS Hornet.  President Nixon personally visited and congratulated the astronauts while they were still in quarantine aboard the USS Hornet.  You can watch a video of this meeting here:

Mankind’s first lunar landing mission was a great success.

Postscript to the first Moon landing

A month after returning to Earth, the Apollo 11 astronauts were given a ticker tape parade in New York City, then termed as the largest such parade in the city’s history.

New York City ticker tape parade for the Apollo 11 astronauts.  
Source: NASA / Bill Taub

There were a total of six Apollo lunar landings (Apollo 11, 12, 14, 15, 16, and 17), with the last mission, Apollo 17, returning to Earth on 19 December 1972.  Their landing sites are shown in the following graphic.

The Apollo landing sites.  Source: NASA

In the past 46+ years since Apollo 17, there have been no manned missions to the Moon by the U.S. or any other nation.

You’ll find extensive Apollo historical resources on the NASA website starting from the following link to the Apollo program webpage: https://www.nasa.gov/mission_pages/apollo/index.html

Along with astronaut John Glenn, the first American to fly in Earth orbit, the three Apollo 11 astronauts were awarded the New Frontier Congressional Gold Medal in the Capitol Rotunda on 16 November 2011. This is the Congress’ highest civilian award and expression of national appreciation for distinguished achievements and contributions.

Neil Armstrong died on 25 August 2012 at the age of 82.

The Apollo 11 command module Columbia was physically transferred to the Smithsonian Institution in 1971 and has been on display for decades at the National Air and Space Museum on the mall in Washington D.C.  For the 50th anniversary of the Apollo 11 mission, Columbia will be on display at The Museum of Flight in Seattle, as the star of the Smithsonian Institution’s traveling exhibition, “Destination Moon: The Apollo 11 Mission.”  You can get a look at this exhibit at the following link:  http://www.collectspace.com/news/news-041319a-destination-moon-seattle-apollo.html

The Apollo 11 command module Columbia at 
The Museum of Flight in Seattle. Source: collectSPACE

After years of changing priorities under the Bush and Obama administrations, NASA’s current vision for the next U.S. manned lunar landing mission is named Artemis, after the Greek goddess of hunting and twin sister of Apollo.  NASA currently is developing the following spaceflight systems for the Artemis mission:

  • The Space Launch System (SLS) heavy launch vehicle.
  • A manned “Gateway” station that will be placed in lunar orbit, where it will serve as a transportation node for lunar landing vehicles and manned spacecraft for deep space missions.
  • The Orion multi-purpose manned spacecraft, which will deliver astronauts from Earth to the Gateway, and also can be configured for deep space missions.
  • Lunar landing vehicles, which will shuttle between the Gateway and destinations on the lunar surface.
The Orion spacecraft is functionally comparable to the Apollo command and
service modules.  Source:  NASA

While NASA has a tentative goal of returning humans to the Moon by 2024, the development schedules for the necessary Artemis systems may not be able to meet this ambitious schedule.  The landing site for the Artemis mission will be in the Moon’s south polar region. NASA administrator Jim Bridenstine has stated that Artemis will deliver the first woman to the Moon.

NASA reported the Artemis moon program status in May 2019 at the following link: https://www.nasa.gov/artemis-moon-program-advances

Additional reading on Project Apollo and the first Moon landing mission:

  • Roger D. Launis, “Apollo’s Legacy: Perspectives on the Moon Landings,” Smithsonian Books, 14 May 2019, ISBN-13: 978-1588346490
  • Neil Armstrong, Michael Collins & Edwin Aldrin, “First on the Moon,” William Konecky Assoc., 15 October 2002, ISBN-13: 978-1568523989
  • Michael Collins, “Flying to the Moon: An Astronaut’s Story,” Farrar, Straus and Giroux (BYR); 3 edition, 28 May 2019, ISBN-13: 978-0374312022
  • Michael Collins, “Carrying the Fire: An Astronaut’s Journeys: 50th Anniversary Edition Anniversary Edition,” Farrar, Straus and Giroux, 16 April 2019, ISBN-13: 978-0374537760
  • Edwin Aldrin, “Return to Earth,” Random House; 1st edition, 1973, ISBN-13: 978-0394488325

India Poised to Become the 4th Nation to Land a Spacecraft on the Moon

This post was updated on 31 July 2019

After the failure of Israel’s Beresheet spacecraft to execute a soft landing on the Moon in April 2019, India is the next new contender for lunar soft landing honors with their Chandrayaan-2 spacecraft.  We’ll take a look at the Chandrayaan-2 mission in this post.

If you’re not familiar with the Israel’s Beresheet lunar mission, see my 4 April 2019 post at the following link:  https://lynceans.org/all-posts/israel-is-poised-to-become-the-4th-nation-to-land-a-spacecraft-on-the-moon/

1. Background:  India’s Chandrayaan-1 mission to the Moon

India’s first mission to the Moon, Chandrayaan-1, was a mapping mission designed to operate in a circular (selenocentric) polar orbit at an altitude of 100 km (62 mi).  The Chandrayaan-1 spacecraft, which had an initial mass of 1,380 kg (3,040 lb), consisted of two modules, an orbiter and a Moon Impact Probe (MIP). Chandrayaan-1 carried 11 scientific instruments for chemical, mineralogical and photo-geologic mapping of the Moon.  The spacecraft was built in India by the Indian Space Research Organization (ISRO), and included instruments from the USA, UK, Germany, Sweden and Bulgaria.  

Chandrayaan-1 was launched on 22 October 2008 from the Satish Dhawan Space Center (SDSC) in Sriharikota on an “extended” version of the indigenous Polar Satellite Launch Vehicle designated PSLV-XL. Initially, the spacecraft was placed into a highly elliptical geostationary transfer orbit (GTO), and was sent to the Moon in a series of orbit-increasing maneuvers around the Earth over a period of 21 days.  A lunar transfer maneuver enabled the Chandrayaan-1 spacecraft to be captured by lunar gravity and then maneuvered to the intended lunar mapping orbit.   This is similar to the five-week orbital transfer process used by Israel’s Bersheet lunar spacecraft to move from an initial GTO to a lunar circular orbit.

The goal of MIP was to make detailed measurements during descent using three instruments: a radar altimeter, a visible imaging camera, and a mass spectrometer known as Chandra’s Altitudinal Composition Explorer (CHACE), which directly sampled the Moon’s tenuous gaseous atmosphere throughout the descent.  On 14 November 2008, the 34 kg (75 lb) MIP separated from the orbiter and descended for 25 minutes while transmitting data back to the orbiter.  MIP’s mission ended with the expected hard landing in the South Pole region near Shackelton crater at 85 degrees south latitude.

In May 2009, controllers raised the orbit to 200 km (124 miles) and the orbiter mission continued until 28 August 2009, when communications with Earth ground stations were lost.  The spacecraft was “found” in 2017 by NASA ground-based radar, still in its 200 km orbit.

Numerous reports have been published describing the detection by the Chandrayaan-1 mission of water in the top layers of the lunar regolith.  The data from CHACE produced a lunar atmosphere profile from orbit down to the surface, and may have detected trace quantities of water in the atmosphere.  You’ll find more information on the Chandrayaan-1 mission at the following links:

2. India’s upcoming Chandrayaan-2 mission to the Moon

Chandrayaan-2 was launched on 22 July 2019.  After achieving a 100 km (62 mile) circular polar orbit around the Moon, a lander module will separate from the orbiting spacecraft and descend to the lunar surface for a soft landing, which currently is expected to occur in September 2019, after a seven-week journey to the Moon.  The target landing area is in the Moon’s southern polar region, where no lunar lander has operated before.  A small rover vehicle will be deployed from the lander to conduct a 14-day mission on the lunar surface.  The orbiting spacecraft is designed to conduct a one-year mapping mission.

Artist’s illustration of India’s lunar lander and the small rover vehicle
on the surface of the moon. Source: ISRO

The launch vehicle

India will launch Chandrayaan-2 using the medium-lift Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk III) developed and manufactured by ISRO.  As its name implies, GSLV Mk III was developed primarily to launch communication satellites into geostationary orbit.  Variants of this launch vehicle also are used for science missions and a human-rated version is being developed to serve as the launch vehicle for the Indian Human Spaceflight Program.

The GSLV III launch vehicle will place the Chandrayaan-2 spacecraft into an elliptical parking orbit (EPO) from which the spacecraft will execute orbital transfer maneuvers comparable to those successfully executed by Chandrayaan-1 on its way to lunar orbit in 2008.  The Chandrayaan-2 mission profile is shown in the following graphic. You’ll find more information on the GSLV Mk III on the ISRO website at the following link:  https://www.isro.gov.in/launchers/gslv-mk-iii

Source:  ISRO
GSLV Mk III D2 on the launch pad at SDSC for the launch of the GSAT-29 communications satellite
in 2018. Source:  ISRO via Wikipedia
GSLV Mk III D1 lifting off from the SDSC with the GSAT-19 communications satellite
in 2017. Source:  ISRO via Wikipedia
Transporting the partially integrated GSLV MkIII M1 launch vehicle
 for the Chandrayaan-2 mission on the Mobile Launch Pedestal.  
Source: ISRO

The spacecraft

Chandrayaan-2 builds on the design and operating experience from the previous Chandrayaan-1 mission.  The new spacecraft developed by ISRO has an initial mass of 3,877 kg (8,547 lb).  It consists of three modules: an Orbiter Craft (OC) module, the Vikram Lander Craft (LC) module, and the small Pragyan rover vehicle, which is carried by the LC.  The three modules are shown in the following diagram.

Three spacecraft modules (not to scale).  Source: ISRO

Chandrayaan-2 carries 13 Indian payloads — eight on the orbiter, three on the lander and two on the rover. In addition, the lander carries a passive Laser Retroreflector Array (LRA) provided by NASA. 

Laser Retroreflector Array (LRA). Source: ISRO

The OC and the LC are stacked together within the payload fairing of the launch vehicle and remain stacked until the LC separates in lunar orbit and starts its descent to the lunar surface.

Orbiter (bottom) & lander (top) in stacked configuration.  Source: ISRO

The solar-powered orbiter is designed for a one-year mission to map lunar surface characteristics (chemical, mineralogical, topographical), probe the lunar surface for water ice, and map the lunar exosphere using the CHACE-2 mass spectrometer.  The orbiter also will relay communication between Earth and Vikram lander.

The orbiter.  Source: ISRO

The solar-powered Vikram lander weighs 1,471 kg (3,243 lb).  The scientific instruments on the lander will measure lunar seismicity, measure thermal properties of the lunar regolith in the polar region, and measure near-surface plasma density and its changes with time. 

The Vikram lander with the Pragyan rover on the ramp. Source: ISRO

The 27 kg (59.5 lb) six-wheeled Pragyan rover, whose name means “wisdom” in Sanskrit, is solar-powered and capable of traveling up to 500 meters (1,640 feet) on the lunar surface. The rover can communicate only with the Vikram lander.  It is designed for a 14-day mission on the lunar surface.  It is equipped with cameras and two spectroscopes to study the elemental composition of lunar soil.

Rover during testing. Source: ISRO
Rover details.  Source: ISRO

You’ll find more information on the spacecraft in the 2018 article by V. Sundararajan, “Overview and Technical Architecture of India’s Chandrayaan-2 Mission to the Moon,” at the following link:

http://epizodsspace.airbase.ru/bibl/inostr-yazyki/Chandrayaan-2.pdf

Also see the ISRO webpage for the GSLV-Mk III – M1 / Chandrayaan-2 mission at the following link:

https://www.isro.gov.in/launcher/gslv-mk-iii-m1-chandrayaan-2-mission

Best wishes to the Chandrayaan-2 mission team for a successful soft lunar landing and long-term lunar mapping mission.