Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Sat, 13 Oct 1990 02:49:01 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 13 Oct 1990 02:48:19 -0400 (EDT) Subject: SPACE Digest V12 #456 SPACE Digest Volume 12 : Issue 456 Today's Topics: History/Benefits of a Space Program? N-waste dissolution into seawater Payload Status for 10/12/90 (Forwarded) Space List: What Every Space Enthusiast Should Know Re: gravity and atmosphere (nitrogen Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 12 Oct 90 16:09:09 GMT From: shl!mark@uunet.uu.net (Mark Batten) Subject: History/Benefits of a Space Program? I am developing some educational materials, the intent being to teach people that space investment is a positive thing, as compared to putting the same money directly into welfare or whatever. I would like to know if someone could help me with two questions, or at least give me pointers to people/books with the answers: a) What are the important milestones in the development of a space program in general (or NASA's history specifically, if you prefer). Especially, what are the dependencies between these milestones? For example, could we have satellites without previously implementing long distance telemetry? Why were earth orbiting missions required before a direct attempt for a moon orbit? And so on... b) What are the classes of spinoffs that have been generated from the space program, especially the ones which most benefit an average person (tang is one overly well known example). I'm looking for things like that or like LANDSAT (helping ecology awareness). Thanks for any help or pointers you can provide. Mark Batten (uunet!shl!mark) ------------------------------ Date: Fri, 12 Oct 90 12:51 EST From: MJENKIN@opie.bgsu.edu Subject: N-waste dissolution into seawater Something's being ignored here. The primary problems with current "disposal" systems are the NIMBY's and ecohysterics. Spreading it into the oceans is just going to make them raise even more $#!+. Besides, as a couple of people quite rightly pointed out (I'm paraphrasing), we're destroying radioactivity in the long run, and why would we want to permanently dispose of materials that are so hard or expensive to find in nature that may very well have future potentials? I say, keep sticking 'em in the old salt mines, make sure they're effectively shielded, and keep working on a fusion reactor. Mark F. Jenkins Bowling Green State University ***guess I gotta come up with a cute little saying, so: "The masses have density." ------------------------------ Date: 12 Oct 90 23:46:40 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Payload Status for 10/12/90 (Forwarded) Daily Status/KSC Payload Management and Operations 10-12-90. - STS-35 ASTRO-1/BBXRT (at VAB) Experiment monitoring continues. - STS-41 Ulysses (at DFRF) Post-flight operations will continue today. - STS-38 DoD MMSE support (at VAB) The canister will be rotated to vertical at the VAB today then transported to the SMAB. - STS-39 AFP-675/IBSS/STP-01 (at CCAFS) Ground software development continues along with cirris vacuum servicing. - STS 40 SLS-1 (at O&C) Module closeouts and MVAK continue. - STS-37 GRO (at PHSF) No work is scheduled for today. - STS-42 IML-1 (at O&C) Module and experiment staging continue. - STS-45 Atlas-1 (at O&C) Experiment and pallet staging continue. - STS-46 TSS-1 (at O&C) Experiment and pallet staging will continue today. - STS-47 Spacelab-J (at O&C) Rack staging continues. - STS-67 LITE-1 (at O&C) No work is scheduled for today. - HST M&R (at O&C) Development of the ADP for shipment of the M&R pallet to GSFC continues. ------------------------------ Date: Fri, 12 Oct 90 14:39:38 PDT From: greer%utdssa.dnet%utadnx@utspan.span.nasa.gov X-Vmsmail-To: UTADNX::UTSPAN::AMES::"space+@andrew.cmu.edu" Subject: Space List: What Every Space Enthusiast Should Know Since everyone else is posting their perennials, I guess its time to post this thing again. I'll try to post it once a month or so in the future. _____________________________________________________________________________ Space List: What every Space Enthusiast Should Know A List of Numbers and Equations Relevant to Space Exploration courtesy Dale M. Greer Update 4: 18-JUN-1990 Solar info from Liam E. Gumley Update 3: 23-MAY-1990 Rocketry info from Dave Newkirk Numbers 9.8 m/s^2 ( 10) -- Acceleration at surface of Earth (one g) 7726 m/s (8000) -- Earth orbital velocity at 300 km altitude 3075 m/s (3000) -- Earth orbital velocity at 35786 km (geosync) 6371 km (6400) -- Mean radius of Earth (Re) 6378 km (6400) -- Equatorial radius of Earth (Re) 1738 km (1700) -- Mean radius of Moon (Rm) 5.974e24 kg (6e24) -- Mass of Earth (Me) 7.348e22 kg (7e22) -- Mass of Moon (Mm) 1.989e30 kg (2e30) -- Mass of Sun (Ms) 3.986e14 m^3/s^2 (4e14) -- Gravitational constant times mass of Earth 4.903e12 m^3/s^2 (5e12) -- Gravitational constant times mass of Moon 1.327e20 m^3/s^2 (13e19) - Gravitational constant times mass of Sun 384401 km ( 4e5) -- Mean Earth-Moon distance 1.496e11 m (15e10) - Mean Earth-Sun distance (Astronomical Unit) 1371 W/m^2 (1400) -- Mean solar constant at 1 AU 6.672e-11 m^3/(kg*s^2) -- Universal gravitational constant 3.08 e13 km parsec 9.46 e12 km light year 0.46 km/s Speed of Earth's rotation at equator 3.0 e8 m/s Speed of light in a vacuum Conversions 1.61 km / mi 0.0254 m / in 3.28 ft / m 0.3048 m / ft 1.467 fps / mph (or 88 fps = 60 mph, exactly) 0.447 m/s / mph 2.2 lb / kg (2.2 pounds-mass, that is) Comparisons 1 MJ = 0.28 kW hr Equations Where d is distance, v is velocity, a is acceleration, t is time. For constant acceleration d = d0 + vt + .5at^2 v = v0 + at v^2 = 2ad General Gravity f = G m1 m2 / r^2 a = v^2 / r g = G Me / r^2 Escape velocity is the critical speed you need to achieve orbit: sqrt(g R) or sqrt(2 G M / R) For circular Keplerian orbits, where u is gravitational constant, a is semimajor axis of orbit, P is period. v^2 = u/a P = 2pi/(Sqrt(u/a^3)) Orbital eccentricity is: e = (apogee - perigee) / 2 r, where r is the average orbital radius. Rocketry The famous delta-v equation for how much velocity you get for burning a portion of fuel is: Dv = Ve LOGe(Mi / Mf), where Ve is the exhaust velocity, Mi is the initial mass, Mf is the final mass This can also be expressed by replacing Ve by g * Isp, where Isp is the specific impulse of the fuel. Here is a different form of the delta-v equation: Dv = Ve LOG(t0 / (t0 - t)), where t0 is the time when all the fuel will be exhausted, and t is the start time. This give the displacement of a constantly accelerating rocket: d = c^2 / a COSH(at/c - 1), where a is acceleration, t is the subjective time, c is speed of light With long time spans and/or high accelerations, this demonstrates special relativity in action. [ Note that COSH(x) = (e^x + e^-x)/2 ] The thrust of a rocket engine can be approximated by: 2 A (p - p0), where A is the minimum nozzle area, p is the chamber pressure, p0 is the pressure outside the engine Or by: Ve * F, where F is the rate of fuel use Miscellaneous f = ma -- Force is mass times acceleration w = fd -- Work (energy) is force times distance Atmospheric density varies as exp(-mgz/kT) where z is altitude, m is molecular weight in kg of air, g is acceleration of gravity, T is temperature, k is Bolztmann's constant. Up to 100 km, d = d0*exp(-z*1.42e-4) where d is density, d0 is density at 0km, is approximately true, so d@12km (13000 m -- 40000 ft) = d0*.18 d@9 km ( 9800 m -- 30000 ft) = d0*.27 d@6 km ( 6500 m -- 20000 ft) = d0*.43 d@3 km ( 3300 m -- 10000 ft) = d0*.65 Quantity Definition Units Energy Q Joules (J) Flux dQ/dt Watts (W) Irradiance dQ/(dt*dA) W per square meter (W/m^2) Monochromatic irradiance dQ/(dt*dA*dl) W/m^2 per micron (W/m^2/um^1) Radiance dQ/(dt*dA*dl*du) W/m^2/um^1 per steradian (W/m^2/um^1/sr^1) Flux at sun surface = 3.92e+26 Watts Selected Planetary Data Semimajor Axis Sidereal Synodic Incl.to Grav.Cst. Mass Period Period Eclipt. GM (10^12 (AU) (Mm) (Tr.Y.) (Days) (deg) m^3/s^2) 10^24kg Mercury 0.3871 57.9 0.24085 115.88 7.0042 22.03 0.33022 Venus 0.7233 108.2 0.61521 583.92 3.3944 324.86 4.8690 Earth 1.0000 149.6 1.00004 403.50 6.0477 Mars 1.5237 227.9 1.88089 779.94 1.8500 42.83 0.64191 Jupiter 5.2028 778.3 11.86223 398.88 1.3047 126712.0 1899.2 Saturn 9.5388 1427.0 29.4577 378.09 2.4894 37934.0 568.56 Uranus 19.1819 2869.6 84.0139 369.66 0.7730 5803.2 86.978 Neptune 30.0578 4496.6 164.793 367.49 1.7727 6871.3 102.99 Pluto 39.44 5900 247.7 366.73 17.17 1 0.012 The Moon 384.4 27.3217days 4.90 0.073483 (Suggestions? Favorite numbers, equations?) _____________ Dale M. Greer Center for Space Sciences, U.T. at Dallas, UTSPAN::UTADNX::UTDSSA::GREER ------------------------------ Date: Fri, 12 Oct 90 15:45:06 EDT From: Richard Ristow Subject: Re: gravity and atmosphere (nitrogen About a week ago, Henry Spencer posted about nitrogen and alternative dilutants in a breathable atmosphere, and among other things speculated >For that matter, we don't know for sure that long-term absence of major >quantities of nitrogen doesn't have some obscure harmful effect. I suggest that for planetary atmospheres (as opposed to short-term breathing and managed biospheres) the absence of nitrogen has a harmful effect that's far from obscure: atmospheric nitrogen is the substrate from which combined nitrogen is produced by biological and abiological 'fixing' processes (the former mainly an enzyme chain in certain prokaryotes, the latter including nitrogen oxydation in lightning strokes). The combined nitrogen is then the substrate for building the nitrogen-containing bio-compounds (including all enzymes and structural proteins) which are crucial for terrestrial life. The bio-nitrogen and inorganic combined nitrogen is extensively recycled in the biosphere, but there is some inevitable loss to atmospheric nitrogen. Having the large atmospheric source for new nitrogen fixation is probably crucial to maintaining the biosphere. ------------------------------ End of SPACE Digest V12 #456 *******************