an artificial-gravity calculator in JavaScript
[About the Calculator]

• Habitat 1.0 For Sale
• Habitat 1.0 0

Habitat 1.0 For Sale

Copyright © 2000
Theodore W. Hall
Last revision: 2018-09-09

About the Calculator

(30 ML) habitat natural-light makeup. With chemical-free sunscreen. May last anywhere from 3- 4 hours depending on the individual. Eau De toilette is less concentrated then Eau de Parfum. It is created with a lighter concentration of fragrance oil, and is ideal for a more subtle impression.

Artificial gravity, as it is usually conceived, is the inertial reaction tothe centripetal acceleration that acts on a body in circular motion. Artificial-gravity environments are often characterized in terms of fourparameters:

Jul 24, 2018 Phase 3: Level 1 of NASA's 3D Printed Habitat Challenge: HexHab is a proposal from team X-ARC for a habitat on the surface of Mars, built autonomously using 3D printed construction techniques with. Oct 18, 2019  If you do not use habitathome.dev.local you will need to modify the Host Name in /sitecore/content/Habitat SXA Sites/Habitat Home/Settings/Site Grouping/Habitat Home after successfully deploying the site. The Habitat Home site will not respond /. Usda nrcs monarch butterfly habitat evaluation guide (wheg), and decision support tool: greater appalachian mountains region edition 1.0 (september 2018). Wildlife habitat continuity (space) December 2017 Page 2. Forage will be harvested at a frequency and height that optimizes the desired forage stand, plant community, and stand life. Harvest forage at the stage of maturity that provides the desired quality and quantity to the degree possible while still providing suitable habitat for the. HABITAT ASSESSMENT FOR HIGH GRADIENT STREAMS Condition Category Habitat. 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 2. Embeddedness Gravel, cobble,. To minimize this cross-coupling, minimize the habitat’s angular velocity. Graybiel 1977 conducted a series of experiments in a 15-foot-diameter “slow rotation room” and observed: In brief, at 1.0 rpm even highly susceptible subjects were symptom-free, or nearly so. At 3.0 rpm subjects experienced symptoms but were not significantly.

• Radius from the center of rotation.
• Angular Velocity or “spin rate.”
• Tangential Velocity or “rim speed.”
• Centripetal Acceleration or “gravity level.”

These four parameters are interdependent: specifying values for any twoof them determines the values of the other two as well.

The calculator assigns a priority to each parameter. Wheneveryou input a value, that parameter receives the highest priority. Thecalculator recomputes the two parameters with the lowest priorities –the two values least recently specified by you. It displays textbeneath each parameter to describe how it determined the value.

The calculator doesn’t update anything until your input iscomplete. Depending on your browser, you may need to press <Tab>or <Enter>, or click the mouse outside the text input area, to triggerthe update.

You can select the measurement unit for each parameter. When youchange a parameter’s unit, the calculator converts the numeric valuewhile holding the physical quantity constant. If you want to specify aparameter value in a unit other than the current selection, select the unitfirst, and then input the numeric value.

The calculator displays the formulae as proportions, designated by thesymbol ∝. Quickbooks. If the angular velocity unit is radians/second, and ifthe other three parameter units are consistent (all meters and seconds, or allfeet and seconds), then the proportion is actually a numeric equality =. (You can verify this by selecting consistent units.) Else, there’sa constant multiplier (not displayed) to account for the unit conversions.

The colored “LED” in front of each parameter indicates how itsvalue compares to the “comfort zone” forartificial gravity, as proposed by several authors:

The value is too high for comfort or will require deliberate adaptation.

The value may be too high for immediate comfort – authors disagree. A period of adaptation may be necessary.

The value is in the comfort zone, with little or no adaptation.

The value may be too low for immediate comfort – authors disagree. A period of adaptation may be necessary.

The value is too low for comfort or will require deliberate adaptation.

If you resize the browser window, the formulae and LEDs may disappeartemporarily. They’ll reappear as you continue to change parametervalues. You can also reset everything by reloading the page.

Comfort Criteria

It should be noted at the outset that, in orbital habitat design, the choiceis not between artificial gravity and Earth gravity, but rather,between artificial gravity and microgravity. Upon entering microgravity,about half of all astronauts endure “space adaptation syndrome” thatlasts from one to three days[Connors, Harrison, Akins, 1985; Merz, 1986]. A similar period of adaptation to artificial gravity seems reasonable,considering the substantial health benefits that it offers versus prolongedweightlessness. It may not be necessary to provide immediate perfect“comfort” in artificial gravity, especially in smallexploration-class vehicles with select crew.

Deliberate architectural design for the unusual conditions of artificialgravity ought to aid adaptation and improve the habitability of theenvironment[Hall, 2006].

The calculator’s comfort indicators are based on the followingcriteria:

Radius
Because centripetal acceleration – the nominal artificial gravity– is directly proportional to radius, inhabitants will experience ahead-to-foot “gravity gradient”. To minimize the gradient,maximize the radius.

Angular Velocity
The cross-coupling of normal head rotations with the habitat rotation can leadto dizziness and motion sickness. To minimize this cross-coupling,minimize the habitat’s angular velocity.

Graybiel [1977]conducted a series of experiments in a 15-foot-diameter “slowrotation room” and observed:

In brief, at 1.0 rpm even highly susceptible subjects were symptom-free,or nearly so. At 3.0 rpm subjects experienced symptoms but were notsignificantly handicapped. At 5.4 rpm, only subjects with lowsusceptibility performed well and by the second day were almost free fromsymptoms. At 10 rpm, however, adaptation presented a challenging butinteresting problem. Even pilots without a history of air sickness didnot fully adapt in a period of twelve days.

On the other hand, Lackner and DiZio [2003]found that:

sensory-motor adaptation to 10 rpm can be achieved relatively easily andquickly if subjects make the same movement repeatedly. This repetitionallows the nervous system to gauge how the Coriolis forces generated bymovements in a rotating reference frame are deflecting movement paths andendpoints and to institute corrective adaptations.

Habitat 1.0 0

Tangential Velocity
When people or objects move within a rotating habitat, they’re subjectedto Coriolis accelerations that distort the apparent gravity. Forrelative motion in the plane of rotation, the ratio of Coriolis to centripetalacceleration is twice the ratio of the relative velocity to thehabitat’s tangential velocity. To minimize this ratio, maximizethe habitat’s tangential velocity.

Centripetal Acceleration
The centripetal acceleration must have some minimum value to offer anypractical advantage over weightlessness. One common criterion is toprovide adequate floor traction. The minimum required to preservehealth remains unknown. For reasons of cost as well as comfort, themaximum should generally not exceed 1 g.

Hill & Schnitzer don’t explain their minimum limit of0.035 g. Compared to the others, it’s an outlier thatappears to be an arbitrary lower bound on their logarithmic graph.

Gilruth doesn’t explain his maximum limit of 0.9 g. Itmay be to allow for additional Coriolis accelerations without exceeding atotal of 1.0 g. This would be better addressed by minimizing theCoriolis accelerations, by maximizing the tangential velocity. Inparticular, in a large rotating colony with high tangential velocity and lowCoriolis acceleration, there should be no comfort problem with a centripetalacceleration of 1.0 g.

I have no data on the upper limit of “comfortable”acceleration. I’ve guesstimated values at which the indicatorshould transition from green to yellow to red. You may think thatI’ve set these limits too low. However, I’m interested inthe maximum acceleration that would be comfortable for normal activity withinthe habitat. This is undoubtedly less than the maximum accelerationtolerable while seated in a padded chair.

References

Connors, Mary M.;Harrison, Albert A.; Akins, Faren R.(1985). Living Aloft: Human Requirements for ExtendedSpaceflight(NASA SP-483, p. 35-51). NASA Scientific and Technical Information Branch.

Cramer, D. Bryant(1985). Physiological Considerations of ArtificialGravity. In A. C. Cron (Ed.),Applications of Tethers in Space,Williamsburg, Virginia, USA, 15-17 June 1983(NASA CP-2364, vol. 1, p. 3·95-3·107). NASA Scientific and Technical Information Branch.

Gilruth, Robert R.(1969). Manned Space Stations – Gateway to our Futurein Space. In S. F. Singer (Ed.),Manned Laboratories in Space(p. 1-10). Springer-Verlag.

Gordon, Theodore J.; Gervais, Robert L.(1969). Critical Engineering Problems of SpaceStations. In S. F. Singer (Ed.),Manned Laboratories in Space(p. 11-32). Springer-Verlag.

Graybiel, Ashton(1977). Some Physiological Effects of Alternation BetweenZero Gravity and One Gravity. In J. Grey (Ed.),Space Manufacturing Facilities (SpaceColonies): Proceedings of the Princeton / AIAA / NASA Conference, May 7-9,1975(p. 137-149). American Institute of Aeronautics and Astronautics.

Hall, Theodore W.(2006). Artificial Gravity Visualization, Empathy, andDesign(AIAA 2006-7321). 2nd International Space Architecture Symposium (SAS 2006), AIAA Space 2006Conference & Exposition, San Jose, California, USA, 19-21 September2006. American Institute of Aeronautics and Astronautics. PDF

Hill, Paul R.; Schnitzer, Emanuel(1962 September). Rotating Manned Space Stations. In,Astronautics(vol. 7, no. 9, p. 14-18). American Rocket Society.

Lackner, James R.; DiZio, Paul A.(2003). Adaptation to Rotating Artificial GravityEnvironments. In,Journal of Vestibular Research(vol. 13, p. 321-330). IOS Press.

Merz, Beverly(1986 October 17). The Body Pays a Penalty for Defying the Law ofGravity. In,Journal of the American Medical Association(vol. 256, no. 15, p. 2040-2041). American Medical Association.

Stone, Ralph W.(1973). An Overview of Artificial Gravity. In A. Graybiel (Ed.),Fifth Symposium on the Role of the VestibularOrgans in Space Exploration,Pensacola, Florida, USA, 19-21 August 1970(NASA SP-314, p. 23-33). NASA Scientific and Technical Information Division.