(2019 Archived) - HAVOC: THE BEGINNING OF A NEW VENUSIAN ERA (Possibly Outdated - Mostly Accurate)

 (Possibly Outdated - Mostly Accurate)

Introduction

As I have mentioned earlier, every grand plan has its humble beginnings. In retrospect, the goldilocks zone of the Venusian atmosphere lies at about ~50-55 kilometres from the surface. It is of manageable temperature and pressure and a haven from cosmic radiation. But how exactly are the Venusians to float within that altitude range? (It is understood that, this has already been talked about in the first chapter, but this chapter provides a deeper understanding into this matter).

 

The Concept of Floating Venusian Habitats

It is universally known that Helium is a lifting gas in regular air. But why? Why does a Helium balloon rise in the air? It is because the Helium in the balloon and the balloon’s fabric combined,  are lighter that the air they displace. The Helium balloon will rise to an altitude, where the weight of the balloon is equal to the weight of the air it displaces. Furthermore, the pressure and density of the air at that altitude, is equal to both the pressure and density of the Helium in the balloon; the system would be at equilibrium.

Similarly, regular air is a lifting gas in Carbon Dioxide, which is the dominant gas in the Venusian atmosphere; Air is naturally buoyant in the Venusian atmosphere. Here is the turn-over: If we were to fill a balloon or a cloud-city with a geodesic structure, the weight of the balloon or the cloud-city will be lighter than, the Venusian air it displaces, and float. Quite neat, isn’t it?

If we were to pressurize a cloud-city with 1 bar (sea-level) pressure, it will float at an altitude with 1 bar atmospheric pressure, or slightly below. And if we were to refer the respective altitude, for the aforementioned pressure range, from a graph: we find out that it coincides with the altitude range of between 50-55 kilometres; the goldilocks zone of the Venusian atmosphere. It is a wonderful coincidence, which makes the parameters of establishing the alleged cloud-city, simpler to a greater extent.

Please note that the concept, which I believe to truly be used for the floatation of the cloud cities, is slightly more modified, and once known, almost seem magical. It isn’t compatible with HAVOC, so we have to begin using this concept. Until then, stay tuned...



Figure 19: Atmospheric pressure as a function of its altitude (on Venus) [25]

Roots of the Concept                                                                

Beforehand, it should be noted that this concept, although not very much heard-of, is relatively not new; it has its roots in the 1970s with the Soviets.  A similar source of origin dating back to the 1980sis about airships on Venus also is from Soviet Russia. I will discuss this second source, in the subsequent section.

Flying Laboratory on Venus (1981)                                              

G. Moskalenko once reflected on the possibility of a long term flying laboratory on Venus, in the 1980s. I found his article to be originally in Russian, and auto-translated it as a reference for this section. He says that we will naturally arrive to the analogues of aerostat or airship, for this purpose, mainly because they can stay in flight for a long time, without requiring energy or fuel [26].

But, the concept he used is more complex; including a balloon filled with a two-component working fluid, which could be used to change flight altitude, using temperature differences of different altitudes. Furthermore, “Calculations show that in real conditions of the atmosphere of Venus, the maximum height of ascent, that is, the flight ceiling for a balloon filled with water vapour, is approximately 39 kilometres; for a balloon filled with methyl vapours-45 kilometres and ammonia vapours- more than hundred kilometres” [26].

Moreover, “depending on the mode of supplying the auxiliary working fluid into the balloon envelope, and the ability to perform translational motion, a wide variety of ‘ascent-descent’ cycles are possible” [26]. This could prove useful, especially for the study of Venus, as access to different altitudes Venus-wide is crucial to it. But in the context of a colony, which needs to stay at a fixed altitude, amidst the goldilocks zone, it might not be as helpful. Our previous strategy, with the usage of air as a lifting gas, is quite adequate.

The Challenges of Venusian Airflight

1.      Sulphuric acid in the atmosphere, might corrode unprotected metal

2.      Significant UV flux in higher altitudes could accelerate degradation through photochemistry [25].

3.      Violent weather conditions, including super-rotation of the Venusian atmosphere, with winds exceeding 200mph, with probable high vertical wind shear [25].

4.      Less solar energy below the clouds.

 

Addressing those Challenges

Teflon and polypropylene could be used to coat aircraft or airship, in order to prevent Sulphuric Acid corrosion. The other challenges are a bit more difficult to address. On the brighter side, the atmospheric density and pressure at ~50-55 kilometres altitude, is similar to that of Earth at sea-level, which makes flying at that altitude aerodynamically similar to flying slightly above the Earth’s surface [27]. (It is easy; Crop-dusters do it without a problem!). Furthermore, the Venusian gravity is slightly lower at 0.904G (8.87ms-1) [12], and slightly aid air flight.



 Figure 20: The above illustration is of a cloud-city on Venus, illustrated in October 1971. This illustration is Flying City of Venus by S. Zhitomorsky, and extracted from the Soviet magazine Technika Molodezhi (Youth Mechanics). It is evidence that floating cloud-cities on Venus has its roots conceptualized, as early as the 1970s.

The Analogues of Airflight                                                    

Moskalenko is still right about us “naturally come[ing] to the analogues of aerostat or airship[s]” [26], because they can be in long-term flight and require less energy.  Moreover, “airships generate lift through buoyancy force, whereas aircraft generate lift through the aerodynamics of fluid flow over the wings. If feasible, each type of vehicle would provide adequate means of controlled flight within the Venus atmosphere” [25].

Furthermore, the most feasible options of powering them are solar power and radioisotope power: “Solar energy-based power system using a photovoltaic array as the main power source and a radioisotope heat source power system utilizing a Stirling engine as the heat conversion device… proved to be the most versatile and provided the greatest range of coverage both for station-keeping and non-station-keeping missions” [27].  

Solar-Powered Airflight                                                              

Venus receives more solar energy than the Earth or Mars, as it is closer to the Sun: “The solar flux at the orbit of Venus is 2600W/m2, which is much greater than the 1360W/m2 available at Earth orbit” [27]. As a matter of fact, it is a ~91.176470588% increase in solar flux, which could significantly increase the performance of solar-powered vehicles. Additionally, there is sufficient solar energy, to power a vehicle, within or even below the cloud-layer: “At the bottom of the cloud layer (45km altitude), the solar intensity is between 520 and 1300 W/m2 depending on wavelength of radiation collected” [27]. Simply, air flight is still technically possible within, and even below the cloud decks.

Radioisotope-Powered Airflight                                               

Long-term flight in the Venusian atmosphere could be done with a radioisotope heat source as a means of powering the vehicle. Out of the near-term conversion systems, a Stirling heat engine is the most recommended, due to its specific power of 8W/kg and conversion efficiency of 32% [25].

Airship Flight on Venus                                                             

Airship flight is possible on Venus, as the thick Venusian atmosphere provides significant buoyancy for generation of lift. However, thick cloud cover and high winds might make it a slightly difficult. A solar-powered airship will have the configuration of a standard cylindrical shape, with three tail fins and two propulsion pods. Furthermore, its solar arrays will be on the upper surface of the airship envelope and tail-fins [27].



Figure 21: A Diagram of a Standard Solar-Powered Venusian Airship [27].

It should be noted that, mass scaling isn’t a critical factor, as “the high density environment of the Venus atmosphere, the lift produced by the envelope volume was more than sufficient to lift the airship and its associated systems” [27]; we can make the airships as enormous as we want them to be.

Aircraft Flight on Venus                                                             

Similar to Airships, Aircrafts can run on both solar power and radioisotope powers. The photovoltaic arrays of a solar-powered aircraft will “convert sunlight to electricity, which is either stored in a silver-zinc battery or utilize[d] directly for the aircraft operation” [27].

Furthermore, “the flight altitude and aircraft size will depend on the power balance between the available power from the solar array and the drag of the aircraft due to the velocity of the wind” [27]. But, unlike a Solar-Powered airship, “the total mass of the solar-powered aircraft is a critical factor in its feasibility” [27].  Moreover, radioisotope-powered aircrafts are limited, not only by its mass scaling, but its ability to generate sufficient lift, as well[27].

Living on a Venusian Airship                                                                 

Airships and aircrafts are quite good as flying laboratories or means of Venusian exploration. But, airships are a more preferable mean of habitation, due to mass scaling not being critical in its feasibility. But, what if we were to live on a Venusian airship?  Couldn’t it prove to be the foundation and experience, for building cloud-cities in the future? Dale C. Arney and Christopher A. Jones, from the Space Mission Analysis and Concepts Directorate at the Langley Research Centre in Virginia, have been exploring the idea [28]. This lead to the formulation of the High Altitude Venus Operational Concept (HAVOC), which I believe will definitely prove to be a milestone in future colonization of Venus, if successful.  But what is HAVOC, and how does it work?



Figure 22: A conceptual sketch of a solar-powered aircraft, flying above the Venusian cloud-tops. Most of solar arrays can be found on the wings [25].      

High Altitude Venus Operational Concept (HAVOC)

The HAVOC (though not much of an optimistic name for a mission) is formulated into five phases, which begins with an exploratory mission with a robotic precursor followed by four manned missions, which include a 30-day orbital stay, a 30-day atmospheric stay, a 1-year atmospheric stay, and permanent residence respectively [28,29}.

Here is a summary of the five phases of the HAVOC [29];

Phase I: Exploratory mission with Robotic Precursor.                                         

 Phase II: 30-day manned mission to Venus Orbit.                                                   

Phase III: 30-day manned mission to Venus Atmosphere.                                 

Phase IV: 1-year manned mission to Venus Atmosphere.                             

Phase V: Permanent residence in Venus Atmosphere.

The vehicle that will be used for the HAVOC missions are the Solar-powered airships, with envelopes filled with Helium [28].  Helium is a better lifting gas, and used to provide buoyancy to the airship, as HAVOC seems to want to be on the safer side. It is a reasonable measure for the HAVOC missions, and perhaps even early colonial missions, with considerable room for error.

Another defining feature of the HAVOC missions is that it doesn’t go along with the conventional EDL (Entry, Descend and Landing) protocol, as “landing would indicate significant failure of the mission” [28], as Dale Arney says in his own words. The airships are supposed to linger above the cloud-tops, and will only land if some failure were to happen. The mission would then truly be havoc! Instead, the HAVOC works in accordance to a new EDI procedure, with the ‘I’ indicating the inflation of the airship.

The Robotic HAVOC Airship and Mission (Phase I)         

The Robotic HAVOC mission is accomplished, with the assistance of a Helium-filled Solar-powered airship, which is 31 metres long and 8 metres tall. It will have a total mass of 1382kg, with a total volume of 1118m3 [29]. The airship has a gondola slung underneath it, for carrying its instruments. 



Figure 23: The inflated airship of the Robotic HAVOC mission [29].  

The robotic airship will carry a payload of its instruments, weighing at 750kg. It will have 96kg tanks, designed to carry a total of 118kg of Helium. The airship’s hull will have a mass of about 201kg, while power and propulsion will occupy 217kg. Thus, the airship’s total mass will add up to 1382kg. The airship will have an area of 50.4m2 of solar array on it, along with an energy storage of 92.9kWh. It will use a power of 11.6 kWe [29].

The airship and its cargo, will be folded up in an aeroshell, and transported to Venus with a spacecraft, which is obviously launched into space with the assistance of a rocket. It will rendezvous (meet/ meet at) with Venus orbit, and de-orbit to enter the atmosphere. It will then jettison its aeroshell and deploy a parachute, allowing the airship to unfurl and inflate. Afterwards, the redundant parachute is jettisoned and the airship will float above the cloud-tops. I suppose the mission will help in scientific study of the atmosphere, along with providing experience for phase-3 of HAVOC. The airship will theoretically have the potential of circumnavigating Venus indefinitely, as long as everything goes as planned. It is, however, surely known that the airship will never return to Earth [Modified from References 29, 30].     

  


             

Figure 24: A diagram of a rocket that will be used in the HAVOC mission. The size of the rocket, along with number of rockets launched will depend on the HAVOC mission we’re talking about [29].

Sulphuric Acid Issues                                                                      

The airships of the HAVOC missions and future exposed areas of the cloud-cities will have to be resistant to Sulphuric Acid. As we have seen earlier, the airship would have to be coated with something acid resistant. Yet, the question remains as to which material is experimentally proven to be effective in doing so, given the acidic conditions of Venus.

Out of the tested materials: Polyvinyl Chloride (PVC) underwent chemical change and lost its transmittance, with transmittance dropping from 80% to 48% in a day, and then to 43% in a month. PVC is therefore, not an ideal material for the purpose. Contrariwise, polypropylene didn’t degrade and had a 90% transmittance. Nevertheless, it might degrade when exposed to temperatures above 50oC. Teflon, on the other hand, had the highest melting point of tested materials, and performed even better with a transmittance of 90-93%. Hence, Teflon and polypropylene are currently recommended for solving the alleged Sulphuric acid issues. Future testing, at a temperature range of 75-80oC are awaited for a more definite result [29].

The Airship of the Manned HAVOC Mission (Phase III)     

Similar to the Robotic HAVOC mission, the manned HAVOC mission is done, with the assistance of a Helium-filled Solar-powered airship. The airship is much larger, with solar arrays on its envelope and tail fins [29].



The airship has a gondola slung underneath it, which carries its ~70 ton payload, which is mostly occupied by an ascent vehicle and an atmospheric habitat. The propellers of the airship, along with the atmospheric habitat are firmly attached, and in fact, a part of the gondola. The ascent vehicle, on the other hand, is a detachable rocket, which could get the crew to Venus orbit [29]. 



The airship, which is 129 metres long and 34 metres tall, will have a total mass of 95,776kg, with a total volume of 77,521m3. The robotic airship will carry a payload of the ascent vehicle and atmospheric habitat, weighing at ~70,000kg. It will have 6,623kg tanks, designed to carry a total of 8,183kg of Helium. The airship’s hull will have a mass of about 6,455kg, while power and propulsion will occupy 4,511kg [29].Thus; the airship’s total mass will add up to 95,776kg. The airship will have an area of 1,044m2 of solar array on it [29], which is surprisingly large. The ascent vehicle and its structure will be discussed slightly later in this chapter [in page 102].

An Abstract on the Manned HAVOC Mission (Phase III)

Similar to any space mission, the crew and material are first launched into space, with the assistance of a rocket. It should be known that, the crew and the airship will undergo the interplanetary voyage separately; the airship folded in the spacecraft, and the crew will follow in a transit vehicle.  After the perilous journey, both the airship and crew will rendezvous in Venus orbit, where the transit vehicle will link-up with the airship, with the crew proceeding in entering the airship [28].

Afterwards, the airship will enter the Venusian atmosphere in an aeroshell, and descend in a ‘Venus Atmosphere Rendezvous (VAR)’ [29]. It would then deploy a parachute, and the aeroshell will drop away. The exposed airship will then proceed with unfurling and inflating. The parachute, which becomes redundant, will be jettisoned [28]. The inflated airship will gently float at an altitude of 52km, at the Venusian equator, where the atmosphere is most stable; and proceed with atmospheric operations [28, 29].

The crew will spend their 30-day atmospheric stay, in the atmospheric habitat, and move into the ascent vehicle when it ends. The ascent vehicle is a two-stage rocket with a tiny capsule known as the ‘ascent habitat’, which would house the crew during ascent: The ascent vehicle will be dropped and ascend to Venus orbit, where the crew will again meet with their transit vehicle. The transit vehicle would again take them on the perilous journey back home, followed by a rendezvous with Earth orbit [28]. Then they will descend through the Earth’s atmosphere, and probably impact the Pacific Ocean, as with the case of Apollo 11. If the mission were to be successful to this extent, the crew will be well received and likely world-famous. But, more importantly, humanity will be a step closer to Venusian colonization.

The above explanation might seem to be quite abbreviated and shallow. I intended it to be so; in the following segments, we will go deeper into each stage of this mission. And don’t worry; I will make this experience well illustrated. Now, we may proceed with A Detailed Analysis of the Manned HAVOC Mission (Phase 3):

 

Launch and Outbound Journey

I believe that the HAVOC airship and crew will be blasted-off into space in separate vehicles with the assistance of two rockets. Afterwards, the airship and crew would begin their outbound journey in space, separately: The airship, which itself is tightly folded in a spacecraft, will journey towards Venus and the crew will follow in a transit vehicle [28].

The transit vehicle consists of a habitat, namely the ‘transit habitat’, which is designed to house a crew of two astronauts for ~400 days. It will have a volume of 44m3 and pressurized at 1 bar. Furthermore, it will use a power of 12kWe, and approved for contingency EVA only. The outbound journey to Venus will take ~110 days and end at VOR (Venus Orbit Rendezvous) [29].



Figure 25: This is a representation of the transit habitat, which would house the crew during the outbound journey to Venus and the Return journey back to the Earth. The transit habitat is located in the transit vehicle accessible to the outside by a ‘doorway’ which could interlock with the ‘un-inflated airship’ during Venus Orbit Rendezvous (VOR), so that the crew can enter the airship. It could also interlock with the ascent habitat, after atmospheric stay and ascent, allowing the crew to re-enter.

VOR and Aerocapture

After ~110days of a hazardous outbound journey, the vehicles will rendezvous with Venus orbit [28]. An aerocapture manoeuvre is required to do this as “the aerocapture manoeuvre is designed to take each vehicle from arrival speeds of approximately 10 to 12 km/s [,] to roughly 7 km/s velocity necessary to hit the desired orbital apogee” [30]. It should be noted that, the airship will arrive to the desired circular orbit after aerocapture, and loiter in Venus orbit until the crew arrives. The transit vehicle will arrive to the same orbit after a little while, again via aerocapture, and link with the airship. The above illustration depicts this scene. The crew will enter the airship, once the vehicles are linked and air-tight [29].



Furthermore, “during aerocapture, the vehicle takes advantage drag created by flying through the atmosphere to reduce the speed of the vehicle, without the use of large propulsive manoeuvre” [30]. Once the vehicle is in desired orbital apogee, atmospheric entry and descent will proceed.

De-orbit and Entry

The airship, once in desired orbital apogee, will de-orbit and descend into the Venusian atmosphere. The airship isn’t inflated yet, and folded in an aeroshell, when atmospheric entry commences. The airship in the aeroshell will enter the atmosphere at a velocity of ~7.2kms-1 (7,200ms-1), specifically in the entry interface of 200km altitude [28, 29, and 30].

It should be noted that, the transit vehicle will continue to orbit Venus and wait until the crew returns. The below illustration depicts the airship descending into the Venusian atmosphere. Moreover, “during entry the Entry Vehicle (EV) is guided through the middle and lower atmosphere and may be manoeuvred to prevent excessive heating and aerodynamic load” [30].



However, this is easier said than done: The sharp density gradient and high entry mass of the manned mission presents certain challenges, to be addressed;

Atmosphere Skip-Out: - If the entry vehicle is travelling at too high a velocity, with too much lift, it might not ‘be captured’ and exit the atmosphere at a reduced speed, and might even not re-enter. This phenomenon is known as ‘atmosphere skip-out’ and not much could be done about it, other than trying to control it; perhaps by using it as a technique for aerocapture or aerobraking [30]                                                                                       

Excessive Lofting: - Lofting is “a repeated increase and decrease in altitude due to excessive lift that may result in atmospheric skip-out” [30]. During atmospheric entry, lofting will have to carefully thought-out.

Excessive G-Loads (Aerodynamic Forces): - Astronauts, in nearly every mission, would be subject to excessive G-loads, which could prove to be injurious, over extended periods of time. NASA already addressed this issue, by establishing G-load limits; which is defined as the “functions of length of exposure and orientation of crew relative to acceleration vector” [30]. Following the G-load limits, is in need of meticulous planning and accurate on-the-spot decision-making. G-loads are an interesting concept, and I recommend looking into it sometime, as I would not feature it as lengthy explanations are needed, for its comprehension in text.

Excessive Aerodynamic Heating: - The high heat rates, which characterize atmospheric entries, would have to be accounted-for. It is the same heat which burns meteorites in our atmosphere, which is simply VERY HOT. A Thermal Protection System (TPS) will be needed to dissipate heat and protect the Entry Vehicle [30].

I believe that, by the time HAVOC is ready; many of these issues would have been looked into, and most likely solved.

 

Deploy Parachute

~7 minutes (~444-522 seconds) after entry, the aeroshell (i.e. the Entry Vehicle) would have slowed down to ~466ms-1 (in a range of ~451-483 ms-1). At this moment, a parachute is deployed, to further slow it down [29]: “Once the EV has slowed down to supersonic velocities, the descent phase begins when an aerodynamic decelerator, such as a parachute or ballute, is deployed to further reduce descent rate” [30]. 



The deployment of the parachute indicates the beginning of the descent phase, which would further decelerate from supersonic to subsonic velocities. The parachute of the manned HAVOC mission has a diameter of 24 metres [30], which would give it an area ~452.5714m2. For further knowledge, the parachute of the Unmanned Robotic HAVOC mission will have a diameter of 10 metres [30], with an area of ~78.5714 m2.

Furthermore, “the airship is pressurized during parachute descent” [30]. The parachute will deploy at an altitude of ~75.1 – 82.7 kilometres above the Venusian surface [29].

The below table the parameters of the parachutes of both the Unmanned and Manned HAVOC missions [30]:

 

Parameters

Unmanned Robotic HAVOC mission. (Phase 1)

Manned HAVOC mission.           (Phase 3)

Diameter

10 m

24 m

Area

76.39822369 m2

31.41592654 m2

Supersonic Drag Coefficient

0.9

0.9

Transonic Drag Coefficient

0.85

0.85

Subsonic Drag Coefficient

1.15

1.15

 

 

Jettison Parachute

~44-64 seconds after the parachute is deployed; the aeroshell will be jettisoned, while the EV is descending at an altitude of ~76.641 - 76.2 km. The exposed and un-inflated airship will now be travelling at a velocity of 96 – 99 ms-1, with the parachute still attached to it. Afterwards, the airship will begin to unfurl and inflate. Before talking of inflation, I would like to talk on the HAVOC Terminal Descent Model (HAVOC-TDM), which was designed during trajectory design. It is a model “developed for analyzing how aerodynamic, buoyancy and inertial forces combine to fix the terminal velocity of the vehicle concept during unpowered descent” [30]. The forthcoming section is based on it.



Figure 26: These rather horribly stitched sets of images are compiled to give an idea on the jettison of the aeroshell.

Airship Inflation

According to the HAVOC-TDM, the airship will inflate at a rate of ~400m3s-1, which would increase its volume sixty-fold, from its original packed volume of ~1,258m3 to its inflated volume of ~77,521m3 [30]. The inflation of the airship would take ~3 minute; approximately 190.6575 seconds, to be precise. The values may differ somewhat from reality, but it shouldn’t seem to be a problem. The table below depicts the entry and descent phases of the manned airship, in accordance to the HAVOC-TDM [30]:

 

EVENT

ALTITUDE [h]

TIME INTERVAL [∆t]

TIME [t]

Begin Entry

69.5 km

58.55 s

58.55 s

Deploy Parachute

69.0 km

2.05 s

60.60 s

Open Parachute

68.0 km

5.48 s

66.08 s

Jettison Aeroshell

64.0 km

30.46 s

96.54 s

Inflation Starts

64 km

35.94 s

96.54 s

Cut Parachute

54.5 km

151.86 s

248.4 s

Inflation Ends

52.0 km

38.8 s

287.25 s

Zero Velocity

52.0 km

66.3 s

353.50 s




This is an illustration of the HAVOC airship, corresponding to its inflation stage. The parachute would then be jettisoned soon after.

Jettison Parachute

The airship, which gets larger due to inflation, will experience an increase in lift and drag, to the point where the parachute is redundant [28]. This happens ~3 minutes (~210 – 221 seconds) after the jettison of the aeroshell [29]. If everything happened as planned, the fully inflated airship would gently float 52 kilometres above Venusian terra [30]. It will gently float near the Venusian equator, where the atmosphere is most stable, with ~100ms-1 winds encircling the planet in ~110 hours [28].

Atmospheric Operations

During entry, descent and the 30-day atmospheric stay, the crew will be housed in the atmospheric habitat. The habitat has a volume of 21m3, pressurized at 1 bar, and use a total power of 3kWe [29].



Figure 27: This is an illustration of the atmospheric habitat [29], which could also be seen in the above image. The front widow will provide a beautiful panoramic view of the Venusian cloud-tops..  



Behold, the spectacular view I was talking of!  I believe that the door seen on the right of this image is the door which was linked it the transit vehicle during VOR. The crew will be in the atmospheric habitat, for the entire atmospheric stay. The airship will use the super-rotation of the Venusian atmosphere, to circumnavigate Venus every 110 hours [28], which roughly translates to every 4.6 days. Thus, the airship and its crew will manage to circumnavigate Venus 6 times, during the atmospheric stay. The crew will be lucky enough to be the first people to witness 6 sunrises and 6 sunsets, from the perspective of the Venusian cloud-tops. The winds will veer north, and the airship would have to push south during the day to stay on course. The might also veer north during the night, to conserve energy. There isn’t much of a reason to perform EVA, which will make this mission simpler and safer [28].

The Ascent Vehicle                                                                           

  The ascent vehicle is a two-stage detachable rocket, which is attached to the gondola of the airship, and occupies majority of mass of the payload. It is comprised of a fist stage, second stage and a little capsule known as the ‘ascent habitat’.



Figure 28: A diagram of the ascent vehicle, which is divided into the rocket stages and ascent habitat [29].

The stages are used to propel the ascent habitat into Venus orbit, with the ascent habitat used to house the crew in that journey [29]. I suppose that the atmospheric habitat has some ‘back-door’, by which the crew can enter the ascent habitat, when the atmospheric stay is over. The ascent habitat is designed to house the crew for up-to a day. It will occupy a volume of 4.6m3, and pressurized at 1 bar, and will use a total power of 1kWe, with no EVAs performed in relation to this habitat [29].

The Ascent to Venus Orbit

Once the 30-day atmospheric stay is over, the crew will enter into the ascent habitat and prepare for another breathtaking stunt: The ascent vehicle will be detached from the gondola and dropped into the Venusian atmosphere [29]. By the way, there is the back-door I was talking of! (Now, the abandoned airship will continue to circumnavigate Venus, as long as nothing happens to it). But, the ascent vehicle will not keep falling to the abyss below:



Afterwards, the rockets of the ascent vehicle will fire, and the ascent vehicle will ascend to Venus Orbit. Stage-by-stage will detach from the ascent vehicle, until only the ascent habitat reaches Venus orbit. Remember the transit vehicle? It had been orbiting Venus, waiting until the crew returns. In Venus orbit, the ascent habitat and the transit habitat will link [28], with their doors interlocking.

The above illustration depicts the linkage of the ascent habitat and transit vehicle, in action. The transit vehicle, in turn, will de-orbit and head to the Earth’s direction. The transit vehicle will now bring the crew back home, in a return trip of ~300days [29]. In the following page; the top image is an illustration of the ascent vehicle, during its ascent to Venus Orbit, while the bottom image is an illustration of the ascent habitat, linking-up with the transit vehicle, with the crew docking into it.




Earth Orbit Rendezvous and Landing

The final stage of this HAVOC mission is to rendezvous with orbit, descent into the Earth’s atmosphere and land [28]. The final capsule will most likely land in the Pacific Ocean, similar to the Apollo11 mission. If the mission were successful, the crew will get to see their families, become world-famous, and be happily received by everyone on the Earth. But again, more importantly, humanity will be a step closer to Venusian colonization.



The Operational Complexities of the Mission and Abort Options of the Rendezvouses                                                                

The VOR (Venus Orbit Rendezvous) poses time delay issues [29], as commands sent as radio waves take time to travel the vast interplanetary distances between the crew and airship, and the ground control on the Earth. Those time delays will have to be accounted-for, with commands likely to be sent accordingly in advance. If anything were to go wrong in VOR, the crew could abort back to the Earth from Venus, in ~300 days [29].

The VAR (Venus Atmosphere Rendezvous) will be challenging, especially for early missions. Unfortunately, VAR is a one-shot trial-or-error manoeuvre, with no abort options [29].

The EOR (Earth Orbit Rendezvous) will be similar to other in-space assembly operations, and we have gained quite a lot of experience in doing so. Nevertheless, if something were to go wrong in EOR, a quicker rendezvous or integration operations are potential abort options [29].

Very Brief Summary of the Manned HAVOC Mission (III)

If this HAVOC mission was hard to visualize or sparks curiosity as to how it might actually look like, then I recommend seeing this link on YouTube: (https://www.youtube.com/watch?v=0az7DEwG68A), which is a lovely animation of this HAVOC mission, published by the Langley Research Centre. I have extracted all un-cited illustrations in this chapter, by freezing that video. Enjoy!

Here is a stage-wise summery of the entire mission:

1.      Launch airship and transit vehicle to space.

2.      Outbound journey to Venus.

3.      Venus Orbit Rendezvous (VOR).

4.      Aerocapture.

5.      Linking; Crew enters the airship.

6.      De-orbit and Entry; Venus Atmosphere Rendezvous (VAR).

7.      Deploy parachute.

8.      Jettison aeroshell.

9.      Airship unfurls and inflates.

10.  Jettison parachute.

11.  Atmospheric stay and operations.

12.  Crew enters ascent vehicle.

13.  Detach ascent vehicle.

14.  Ascent to Venus orbit.

15.  Linking; Crew return to transit vehicle.

16.  Return Journey to the Earth.

17.  Entry and descent into the Earth’s atmosphere.

18.  Landing (perhaps in the Pacific Ocean).

The below illustration is a detailed and diagrammatic depiction of the entry and descent phase, of the HAVOC airship. (Extracted from reference 29):



Proof of Concept

A 1:50 scale model of the HAVOC airship, developed by the HAVOC team, was successfully packed into an aeroshell and inflated out of it and floated [28, 29]. It proves that the HAVOC airship could do what it is supposed to do.



Figure 29: The 1:50 scale model of the HAVOC airship, developed by the HAVOC team, which was successfully packed into an aeroshell, and inflated out of it [29]

Conclusion [In association with reference 28]

The HAVOC team believes that the concept “offers a realistic target for crewed exploration in the near future, pending moderate technological advancements and support from NASA” [28]. My belief is similar: Venus has been largely ignored since the 1980s despite its potential for scientific discovery and as a second home. Even if Mars were to be a destination for a manned mission, the HAVOC missions could give a leg-up in advancing the related technologies and would be similar to a practice run.

Moreover, it will give us the experience we need regarding long-duration habitats, aerobraking, aerocapture and Carbon Dioxide processing. The HAVOC mission would play a major role in humanity’s future in space.

The Manned Mission to Venus Orbit (Phase II)

There is an intermediary mission between the Unmanned Robotic HAVOC mission, and the already discussed manned HAVOC mission (Phase 3). The Unmanned Robotic HAVOC mission will give us the experience of entry, descent and inflation; but it is a bit too soon for an immediate manned mission of a similar calibre (referring to phase III). The Phase II manned mission was formulated for more practice, before the phase III manned mission, which we discussed.

Not much is revealed of this mission, but a general idea can be obtained in comparison with objective of the mission; a 30-day stay in Venus orbit, and the phase III mission. I believe it to be as follows: The crew will be blasted-off into space in a single vehicle, with the assistance of a single rocket, and head outwards to Venus in a journey of ~110 days. Afterwards, the crew will rendezvous with Venus orbit, and orbit Venus for 30 days. Afterwards, the crew will return to Earth in a journey of ~300 days, rendezvous with Earth orbit, enter and descend into the Earth’s atmosphere, and finally land.

 

The Manned HAVOC Mission with 1-Year Atmospheric Stay (Phase IV)

This mission will take place after the phase-III HAVOC mission with 30-day atmospheric stay. This mission isn’t very discussed because; (i) It is meant for the future, which isn’t as much a priority as the first three HAVOC missions.(ii) It would require development in self-sufficiency, resource management systems and methodologies of using the Venusian environment for the crew’s benefit and for extracting resources. (iii) The dimensions and plan of the mission have not been comprehensively designed yet, and the potential problems are not worth solving at present.

However, based on our current knowledge, there are a few features we can identify of this mission. (1) I believe that the mission will have a larger crew who would carry-out activities of more variety. (2) The airship will have to have larger dimensions – most likely enormous! Or it might even be comprised of many airships. (3) I believe that more rockets would be used to send the crew and required material to Venus. (4) The airship would likely circumnavigate Venus ~80 times, before atmospheric stay is over. (5) The ascent and transit vehicle will have larger dimensions, or many ascent and transit vehicles might be used. (6) I believe that either the crew will happen to use their resources in a self-sufficient system, or that supplies will arrive for them via aeroshells, or both. (7) The mission might include EVA during atmospheric stay, due to long duration. (8) There will be a lot of experimentation and scientific research happening on-board this mission. (9) The astronauts might be provided more facilities and activities. (10) I believe that systems for extracting resources from the Venusian atmosphere might be used and maintained.

I believe that this is quite an advanced mission, which is quite a huge leap from the phase-III manned mission, and that the mission could be re-done based on success, ‘non-success’, or even failure of this mission. Still, true failure would tend to be quite unlikely, as (11) more abort options could be formulated. Nevertheless, based on my views, (12) success in this mission would be synonymous to success in establishing a Venusian presence, like a proto-colony. What I meant here is that; if we can sustain a proto-colony in the Venusian cloud-tops for a year, we could do so for much longer periods of times; perhaps for decades, centuries, even millennia!

And that is exactly the next phase, if this mission were a success: permanent residence in the Venusian cloud-tops. 

 

Permanent Residence (Phase V)

The final phase of HAVOC aims at establishing a permanent human presence on the Venusian cloud-tops. It will include large floating structures, which are solar-powered and float on the buoyancy of the Helium. The colonists would live in these structures, extract resources and utilize them in a self-sufficient system. The below illustration depicts how the Venusian cloud-tops might look like in the beginning of this stage [29].

I would sometimes imagine the lives of the first official Venusian colonists, who would call these structures home. I believe that they will be amazed at the blueness of the sky above, and the whiteness of the clouds below; for an alien world, it does a good job at resembling the Earth! It would be interesting to see the sun rise from the west and set in the east, but twice as slowly. I believe that the colonists would maintain and harvest communal farms, while potentially surviving on some supplies from the Earth, which arrive in aeroshells. While not farming or performing EVA, I believe that that they would spend their time experimenting or enjoying their leisure, perhaps communicating with their kith and kin, or perhaps with creative activities or forms of entertainment.

The night might be of their fancy too, perhaps with stargazing with altered constellations; Orion’s belt not straight, and the Great Dipper warped. But the highlight of the night sky would be a distinctive blue star, reminiscent of the colonists’ origins; The Earth. Furthermore, I appreciate the role those pioneer colonists, in the utopian future humanity will behold. 



Restrictions for HAVOC

In its current incarnation, the manned HAVOC mission “depends on the massive Block IIB configuration of the space launch system, which may not be ready to fly until the late 2020s” [28]. But I believe that it isn’t the main restriction; That would be belief itself. I feel that we’re almost conditioned to appreciate and support manned Martian exploration and Martian colonization; to believe that Mars is more suitable for the purpose, even when the possibility of another is exposed. After all, I used to be the same, before stumbling across that life-changing article. A similar story might have happened to others, in an ever-increasing population of people who see potential in Venus.

 

On the True colonization of Venus: A Foreword to the Subsequent Chapters.

But, a question arises: Is the HAVOC series of missions truly the colonization of Venus? I’m afraid not; The HAVOC missions are only the foundation; the pioneering; the initial stage before true colonization of Venus. Still, I regard the phase- IV HAVOC mission to be a proto-colony, while the phase V HAVOC mission to be an initial colony. But, before asking how to colonize Venus, we have to answer another question, or rather a series of questions:

What is colonization? What makes a colony, a colony? How does a colony grow to independence? How can we apply our knowledge of successful and triumphant colonization, to the context of Venus? 

Well, the consequent chapter is dedicated to answering all these concerning questions, along with the aspiration of providing an insight to the milieus of Venusian colonization 

Old Bibliography (Below)

Achinthya Nanayakkara (31.03.2025)

Original - 2019

 

                             


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