| Archive-name: space/controversy |
| Last-modified: $Date: 93/04/01 14:39:06 $ |
| These issues periodically come up with much argument and few facts being |
| offered. The summaries below attempt to represent the position on which |
| much of the net community has settled. Please DON'T bring them up again |
| unless there's something truly new to be discussed. The net can't set |
| public policy, that's what your representatives are for. |
| Despite a widespread belief to the contrary, the Saturn V blueprints |
| have not been lost. They are kept at Marshall Space Flight Center on |
| microfilm. |
| The problem in re-creating the Saturn V is not finding the drawings, it |
| is finding vendors who can supply mid-1960's vintage hardware (like |
| guidance system components), and the fact that the launch pads and VAB |
| have been converted to Space Shuttle use, so you have no place to launch |
| from. |
| By the time you redesign to accommodate available hardware and re-modify |
| the launch pads, you may as well have started from scratch with a clean |
| sheet design. |
| Investigators associated with NASA missions are allowed exclusive access |
| for one year after the data is obtained in order to give them an |
| opportunity to analyze the data and publish results without being |
| "scooped" by people uninvolved in the mission. However, NASA frequently |
| releases examples (in non-digital form, e.g. photos) to the public early |
| in a mission. |
| There has been extensive discussion on this topic sparked by attempts to |
| block the Galileo and Ulysses launches on grounds of the plutonium |
| thermal sources being dangerous. Numerous studies claim that even in |
| worst-case scenarios (shuttle explosion during launch, or accidental |
| reentry at interplanetary velocities), the risks are extremely small. |
| Two interesting data points are (1) The May 1968 loss of two SNAP 19B2 |
| RTGs, which landed intact in the Pacific Ocean after a Nimbus B weather |
| satellite failed to reach orbit. The fuel was recovered after 5 months |
| with no release of plutonium. (2) In April 1970, the Apollo 13 lunar |
| module reentered the atmosphere and its SNAP 27 RTG heat source, which |
| was jettisoned, fell intact into the 20,000 feet deep Tonga Trench in |
| the Pacific Ocean. The corrosion resistant materials of the RTG are |
| expected to prevent release of the fuel for a period of time equal to 10 |
| half-lives of the Pu-238 fuel or about 870 years [DOE 1980]. |
| To make your own informed judgement, some references you may wish to |
| pursue are: |
| A good review of the technical facts and issues is given by Daniel |
| Salisbury in "Radiation Risk and Planetary Exploration-- The RTG |
| Controversy," *Planetary Report*, May-June 1987, pages 3-7. Another good |
| article, which also reviews the events preceding Galileo's launch, |
| "Showdown at Pad 39-B," by Robert G. Nichols, appeared in the November |
| 1989 issue of *Ad Astra*. (Both magazines are published by pro-space |
| organizations, the Planetary Society and the National Space Society |
| respectively.) |
| Gordon L Chipman, Jr., "Advanced Space Nuclear Systems" (AAS 82-261), in |
| *Developing the Space Frontier*, edited by Albert Naumann and Grover |
| Alexander, Univelt, 1983, p. 193-213. |
| "Hazards from Plutonium Toxicity", by Bernard L. Cohen, Health Physics, |
| Vol 32 (may) 1977, page 359-379. |
| NUS Corporation, Safety Status Report for the Ulysses Mission: Risk |
| Analysis (Book 1). Document number is NUS 5235; there is no GPO #; |
| published Jan 31, 1990. |
| NASA Office of Space Science and Applications, *Final Environmental |
| Impact Statement for the Ulysses Mission (Tier 2)*, (no serial number or |
| GPO number, but probably available from NTIS or NASA) June 1990. |
| [DOE 1980] U.S. Department of Energy, *Transuranic Elements in the |
| Environment*, Wayne C. Hanson, editor; DOE Document No. DOE/TIC-22800; |
| Government Printing Office, Washington, D.C., April 1980.) |
| From time to time, claims are made that chemicals released from |
| the Space Shuttle's Solid Rocket Boosters (SRBs) are responsible |
| for a significant amount of damage to the ozone layer. Studies |
| indicate that they in reality have only a minute impact, both in |
| absolute terms and relative to other chemical sources. The |
| remainder of this item is a response from the author of the quoted |
| study, Charles Jackman. |
| The atmospheric modelling study of the space shuttle effects on the |
| stratosphere involved three independent theoretical groups, and was |
| organized by Dr. Michael Prather, NASA/Goddard Institute for Space |
| Studies. The three groups involved Michael Prather and Maria Garcia |
| (NASA/GISS), Charlie Jackman and Anne Douglass (NASA/Goddard Space |
| Flight Center), and Malcolm Ko and Dak Sze (Atmospheric and |
| Environmental Research, Inc.). The effort was to look at the effects |
| of the space shuttle and Titan rockets on the stratosphere. |
| The following are the estimated sources of stratospheric chlorine: |
| Industrial sources: 300,000,000 kilograms/year |
| Natural sources: 75,000,000 kilograms/year |
| Shuttle sources: 725,000 kilograms/year |
| The shuttle source assumes 9 space shuttles and 6 Titan rockets are |
| launched yearly. Thus the launches would add less than 0.25% to the |
| total stratospheric chlorine sources. |
| The effect on ozone is minimal: global yearly average total ozone would |
| be decreased by 0.0065%. This is much less than total ozone variability |
| associated with volcanic activity and solar flares. |
| The influence of human-made chlorine products on ozone is computed |
| by atmospheric model calculations to be a 1% decrease in globally |
| averaged ozone between 1980 and 1990. The influence of the space shuttle and |
| Titan rockets on the stratosphere is negligible. The launch |
| schedule of the Space Shuttle and Titan rockets would need to be |
| increased by over a factor of a hundred in order to have about |
| the same effect on ozone as our increases in industrial halocarbons |
| do at the present time. |
| Theoretical results of this study have been published in _The Space |
| Shuttle's Impact on the Stratosphere_, MJ Prather, MM Garcia, AR |
| Douglass, CH Jackman, M.K.W. Ko and N.D. Sze, Journal of Geophysical |
| Research, 95, 18583-18590, 1990. |
| Charles Jackman, Atmospheric Chemistry and Dynamics Branch, |
| Code 916, NASA/Goddard Space Flight Center, |
| Greenbelt, MD 20771 |
| Also see _Chemical Rockets and the Environment_, A McDonald, R Bennett, |
| J Hinshaw, and M Barnes, Aerospace America, May 1991. |
| If you *don't* try to hold your breath, exposure to space for half a |
| minute or so is unlikely to produce permanent injury. Holding your |
| breath is likely to damage your lungs, something scuba divers have to |
| watch out for when ascending, and you'll have eardrum trouble if your |
| Eustachian tubes are badly plugged up, but theory predicts -- and animal |
| experiments confirm -- that otherwise, exposure to vacuum causes no |
| immediate injury. You do not explode. Your blood does not boil. You do |
| not freeze. You do not instantly lose consciousness. |
| Various minor problems (sunburn, possibly "the bends", certainly some |
| [mild, reversible, painless] swelling of skin and underlying tissue) |
| start after ten seconds or so. At some point you lose consciousness from |
| lack of oxygen. Injuries accumulate. After perhaps one or two minutes, |
| you're dying. The limits are not really known. |
| References: |
| _The Effect on the Chimpanzee of Rapid Decompression to a Near Vacuum_, |
| Alfred G. Koestler ed., NASA CR-329 (Nov 1965). |
| _Experimental Animal Decompression to a Near Vacuum Environment_, R.W. |
| Bancroft, J.E. Dunn, eds, Report SAM-TR-65-48 (June 1965), USAF School |
| of Aerospace Medicine, Brooks AFB, Texas. |
| The Challenger shuttle launch was not destroyed in an explosion. This is |
| a well-documented fact; see the Rogers Commission report, for example. |
| What looked like an explosion was fuel burning after the external tank |
| came apart. The forces on the crew cabin were not sufficient to kill the |
| astronauts, never mind destroy their bodies, according to the Kerwin |
| team's medical/forensic report. |
| The astronauts were killed when the more-or-less intact cabin hit the |
| water at circa 200MPH, and their bodies then spent several weeks |
| underwater. Their remains were recovered, and after the Kerwin team |
| examined them, they were sent off to be buried. |
| You can't use the shuttle orbiter for missions beyond low Earth orbit |
| because it can't get there. It is big and heavy and does not carry |
| enough fuel, even if you fill part of the cargo bay with tanks. |
| Furthermore, it is not particularly sensible to do so, because much of |
| that weight is things like wings, which are totally useless except in |
| the immediate vicinity of the Earth. The shuttle orbiter is highly |
| specialized for travel between Earth's surface and low orbit. Taking it |
| higher is enormously costly and wasteful. A much better approach would |
| be to use shuttle subsystems to build a specialized high-orbit |
| spacecraft. |
| [Yet another concise answer by Henry Spencer.] |
| There really is a big rock on Mars that looks remarkably like a humanoid |
| face. It appears in two different frames of Viking Orbiter imagery: |
| 35A72 (much more facelike in appearance, and the one more often |
| published, with the Sun 10 degrees above western horizon) and 70A13 |
| (with the Sun 27 degrees from the west). |
| Science writer Richard Hoagland has championed the idea that the Face is |
| artificial, intended to resemble a human, and erected by an |
| extraterrestrial civilization. Most other analysts concede that the |
| resemblance is most likely accidental. Other Viking images show a |
| smiley-faced crater and a lava flow resembling Kermit the Frog elsewhere |
| on Mars. There exists a Mars Anomalies Research Society (sorry, don't |
| know the address) to study the Face. |
| The Mars Observer mission will carry an extremely high-resolution |
| camera, and better images of the formation will hopefully settle this |
| question in a few years. In the meantime, speculation about the Face is |
| best carried on in the altnet group alt.alien.visitors, not sci.space or |
| sci.astro. |
| V. DiPeitro and G. Molenaar, *Unusual Martian Surface Features*, Mars |
| Research, P.O. Box 284, Glen Dale, Maryland, USA, 1982. $18 by mail. |
| R.R. Pozos, *The Face of Mars*, Chicago Review Press, 1986. [Account of |
| an interdisciplinary speculative conference Hoagland organized to |
| investigate the Face] |
| R.C. Hoagland, *The Monuments of Mars: A City on the Edge of Forever*, |
| North Atlantic Books, Berkeley, California, USA, 1987. [Elaborate |
| discussion of evidence and speculation that formations near the Face |
| form a city] |
| M.J. Carlotto, "Digital Imagery Analysis of Unusual Martian Surface |
| Features," *Applied Optics*, 27, pp. 1926-1933, 1987. [Extracts |
| three-dimensional model for the Face from the 2-D images] |
| M.J. Carlotto & M.C. Stein, "A Method of Searching for Artificial |
| Objects on Planetary Surfaces," *Journal of the British Interplanetary |
| Society*, Vol. 43 no. 5 (May 1990), p.209-216. [Uses a fractal image |
| analysis model to guess whether the Face is artificial] |
| B. O'Leary, "Analysis of Images of the `Face' on Mars and Possible |
| Intelligent Origin," *JBIS*, Vol. 43 no. 5 (May 1990), p. 203-208. |
| [Lights Carlotto's model from the two angles and shows it's consistent; |
| shows that the Face doesn't look facelike if observed from the surface] |
| NEXT: FAQ #13/15 - Space activist/interest/research groups & space publications |
|
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