Space Transportation - mmmt_transportation.pdf - Moon Society

MMM #115 - May 1998
High Sky Aircraft for Venus
By Peter Kokh
JOB DESCRIPTION
If we are going to have any number of science station and industrial aerostat hamlets in “the high skies” over
Venus, we’ll need reliable, easily kept up, worry-free, locally co-manufactured 1 means of transporting people and
cargo in between. That’s a mouthful of design constraints. Can we deliver?
With the surface off limits to casual ventures, aerial transit is it. And none of our Veneran aircraft will be
“landing” or “taking off”. They will be “arriving” and “departing” — from midair docking gates.
Craft suited for such purposes may have very limited ability to cope with the greater pressures and heat levels
of successively lower layers of the atmosphere. It would seem essential to design into them passive fail-safe buoyancy
systems to prevent such misadventures.
FUEL & ENGINES
Methanox (methane/oxygen) is a serviceable fuel combination for both reciprocating prop engines and for
rockets. Most importantly, both fuel and oxidizer can be processed on Venus from the atmosphere where its exhaust
will return it in the form of the original ingredients.
As landing is not an option in distress situations, some form of back-up power for electric taxi props would
be prudent. Another option, however, is to have the entire upper surface of the craft serve as a rectenna for guidebeam
slaved Solar Power Satellite microwave transmissions. Such systems, it’d seem, would be pioneered on Earth
long before we’ll need them on Venus, and by then be a stock item.
Where sprint-rescue speeds are not needed, propeller-driven craft promise the greatest fuel efficiency with
adequate speeds as well as superior low speed performance for dock approaches and departures. Aircraft can safely
fly at the 1 ATM aerostat level but need climbing ability to reach thinner air for more efficient cruising.
While fuel tanks should be ample for long range and extended cruising and bad weather and other emergency
situations, again because landing is not an option, Veneran aircraft should have midair refueling capability. Midair
docking capacity for exchanges of crew, passengers, and cargo would be an invaluable advantage, brining enormous
flexibility.
To avoid construction of aerial runways that offering surface friction to assist braking and deceleration and
provide a platform for acceleration to lift speeds, aircraft should either be buoyant or have some sort of Harrier or
other type VTOL or hovering capacity. This would help in midair docking.
CONSTRUCTION & COMPONENTS
Lightweight Kevlar components, manufactured in Veneran high sky facilities, will provide greater strength and
lessen the weight to be managed in maintaining lift, buoyancy, and hovering ability. Small complex subassemblies
(navigation avionics , other electronics, control & communication systems, airtight docking ports, etc.) can be
imported from Earth to mate with Venus-made fuselages, wings, fuel tanks, cabin interiors, and other items designed
for ease of on site manufacture and assembly.
A whole family of Veneran aircraft will be needed: small crew transports, smaller and larger passenger craft,
craft dedicated for cargo, fast sprint rescue and response craft. Maintaining a “family’ resemblance along with the
maximum percentage of interchangeable parts will be of compelling benefit.
FAIL-SAFE & JUST-IN-TIME LIGHTER THAN AIR
Obviously, the dirigible is one viable option along with other possible lighter-than-air architectures (there is
now a renaissance in interest along with increased exploration of new design options). But full-time partial buoyancy
and buoyancy-on-demand with fail-safe, dead man deployment systems will also work while allowing more
streamlined designs and faster cruising speeds.
Hydrogen-filled bags that passively inflate whenever certain impeding conditions degrade will make the High
Skies safe for all Venerans to fly. These conditions include minimum speed, maximum desirable or tolerable air
density and/or temperatures, as well as certain internal conditions (loss of fuel, power, active crew).
To more efficiently negotiate different altitude ranges as well as variable speeds. wing and/or lift surface
designs that allow the loading to be varied are a downrange design consideration.
SPECIAL DUTY CRAFT FOR SURFACE EXPLORATION
On Earth, we have built oceanic submersibles that have withstood over 1,000 ATMs of external hull pressure.
So it is temperature, not pressure, that looms as the most challenging hurdle facing would be surface exploration
craft, including VTOL aircraft and wheeled gondola cabins lowered and lifted by collapse and store balloons. As an
interim measure, mid-altitude aircraft could lower retrievable instrumented science/communications packages on
tethers.
COMMUNICATIONS
How serviceable line-of-sight radio communications will be, is unknown. With less of a magnetosphere, solar
or cosmic noise could be a big problem on Venus. Satellites could offer GPS navigation assist as well as
communications relay. But so could heat and pressure-hardened surface relay stations.
On this as on other challenges above, the old adage applies. “Where there is a will, (and no defeatist attitude!)
there’s a way.” “High Skies!”
47