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 ; Wed, 7 Mar 90 01:41:24 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 7 Mar 90 01:40:57 -0500 (EST) Subject: SPACE Digest V11 #120 SPACE Digest Volume 11 : Issue 120 Today's Topics: Re: Rocket Info space news from Jan 29 AW&ST etc Galileo Update - 03/05/90 Space capsules (was Re: space news from Jan 22 AW&ST) Re: Rocket Info ---------------------------------------------------------------------- Date: 6 Mar 90 17:32:03 GMT From: zaphod.mps.ohio-state.edu!uwm.edu!mrsvr.UUCP@tut.cis.ohio-state.edu (Russ Brown) Subject: Re: Rocket Info > >I'm preparing a simple programming assignment for my students and I wonder >if someone could give me some figures. Does anyone have a rough estimate of >mass of a rocket (esp. Saturn V)? How about fuel capacity? How about >a conversion factor between kilograms of fuel and thrust (in Newtons)? >-- Heres some stuff from "Bound for the Stars", Adelman & Adelmand, Prentice- Hall, 1981. (Chapter 5) - One pound of hydrogen and oxygen burning for one second exerts 456 pounds of force. This gives it a 'specific impulse' of 456 seconds. "Hydrogen-Oxygen is the highest specific impulse of any chemical combination of fuels in use today". - Takeoff mass of the Apollo 11 spaceship was 2,902,216 kg. First stage thrust was 34.1 million Newtons. Comparison of modern engines: J-2 SSME ---------------------------------------------------------- MASS OF ENGINE 1530 kg 2835 kg THRUST (VACUUM) 1.02 x 10^6 N 2.08 x 10^6 N THRUST-WEIGH RAT 68:1 81:1 SPECIFIC IMPULSE 430 sec 455 sec You might try to find this book at the library. Also, Encyclopedia Britannica has a table of specific impulses in the macropedia article on "energy conversion", or something like that. And the section on space exploration has data on each of the launch vehicles. ------------------------------ Date: 6 Mar 90 04:30:10 GMT From: jarvis.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: space news from Jan 29 AW&ST etc Editorial applauding the retrieval of LDEF, but observing that NASA had to choose between LDEF and Solar Max, and lamenting that the $20M LDEF cost far more than that to launch and retrieve and is unlikely to fly again. IBM subcontracts operating system for space station to Lynx Real-Time Systems Inc, a 30-employee company in California! NASA seeks $200M in FY91 for lunar/Mars technology work in seven areas: regenerative life support, aerobraking, orbital propulsion, lunar-base nuclear power, uses of lunar/Martian soil, radiation protection, and nuclear propulsion. Truly recommends to Space Council that "the first decade of the 21st century" be the target goal for a lunar base. [Call it 19 years. Apollo took 8. I'm not impressed.] NASP prime contractors submit a tentative agreement to join together in a consortium to pillage the taxpayers, er excuse me I mean build NASP, more efficiently. The FY90-91 DoD budget authorization act will designate NASP as a pure research vehicle, to do an end-run around antitrust laws. Rockwell is designated team leader, possibly partly because it has stuck most firmly to the original idea of maximizing use of air-breathing propulsion and minimize dependence on rockets. SDI's LACE satellite being prepared for launch on a Delta. The main payload is the Low-power Atmospheric Compensation Experiment, in which sensors scattered over booms and panels extending from the bird will measure distortion of a low-power laser beam aimed at the satellite from the surface. Auxiliary payloads include a pair of ultraviolet cameras to study UV tracking of rocket plumes, and an Army/Los Alamos experiment to measure neutron background in space. There may also be "a fourth, classified experiment... believed to be developmental hardware for detecting nuclear blasts", which is not from SDI. LDEF is on the ground again. The backup plan, for use if Syncom could not be deployed -- take LDEF on board, boost up to a higher orbit, and deploy it again pending a still later retrieval (!) -- was not needed. Landing was delayed a day by fog at Edwards, and delayed one more orbit by a failure in Columbia's #5 computer (#4 replaced it for the landing). The astronauts took their time coming out after landing, and are generally taking it easy, after the longest US spaceflight in fifteen years [a whole 11 days, sigh...]. LDEF will go back to KSC aboard the orbiter, partly because this will contaminate it less than separate shipping and partly because removing a payload that big would require moving quite a bit of equipment from KSC to Edwards temporarily. The 747 will make three stops rather than the usual one, because the unusually heavy load limits fuel load. Hubble launch slips a month as incomplete test data raises doubts about seals on Discovery's SRBs. They will be taken apart and re-stacked. Secret DoD launch of Atlantis slips six days, probably a payload problem. The bird is "AFP-731", with both digital imaging systems and eavesdropping receivers, and it will go into an unusually high-inclination orbit, 62 degrees. Only two more military payloads are on the shuttle manifest after this one, and the USAF asst. sec. for space says no more are planned, although the option will remain open. "We don't have anything that specifically requires the manned capability..." [Translation, everything requiring the manned capability was shelved because the USAF's expendables have no manned capability.] First Ariane launch of 1990 goes perfectly, carrying Spot 2, plus six amateur radio satellites on a new auxiliary-payload carrier platform. This launch, Jan 21, ends a hiatus in Ariane operations due mostly to payload problems. [Of course, there is now going to be another hiatus, since the *next* Ariane launch wasn't so smooth...] On reaching orbit, Spot 2 was deployed, the Ariane third stage turned 180 degrees and deployed UoSAT D and E, and then turned back 25 degrees to release Microsats A-D. The individual UoSAT/Microsats were deployed by springs of different strengths to ensure separation. The UoSAT/Microsat folks split the secondary-payload bill of about $170k (normally $600k, but this was the first flight of the new secondary-payload platform). Several pages of photos of LDEF in space. MBB is defining a subscale model of Sanger's hypersonic first stage, for use in validating design and propulsion. Letter from J.R. French [a well-known name in astronautics] criticizing AW&ST's "Laurels" award to the team that put together NASA's initial response to Bush's Moon/Mars initiative. "...simply a rehash of the sort of thing NASA has been promoting all along, namely taking 15 years to do what we once did in eight, starting with nothing... NASA spent the 90-day study justifying a pre-established position rather than doing any new thinking... `space station Freedom', recently downscaled because of budget problems, magically grows back to the old configuration for Moon-Mars. This is design to preconception -- not design to need..." [Something that wasn't in AW&ST at all, that I saw, but reached me by more obscure channels: NASA has placed an order with Rockwell for a set of shuttle structural spares, to replace the ones being used to build Endeavour. Apart from being useful in themselves, they preserve the option of ordering another orbiter in the next year or two.] [From Spaceflight, Jan issue:] Salyut 7 is out of fuel and tumbling, and the Soviets are studying how to deorbit it safely. Reentry will occur in 3-4 years as things stand. One possibility is to dock a Progress or Soyuz and use its engines to deorbit Salyut. Reports that Buran would be used to bring Salyut down for examination are described as "a kind of fantasy", presenting various problems with solar panels and structural support, that does not seem worthwhile at present. Salyut has been unmanned in a high parking orbit since 1986, although there were reports that astronauts would return to it eventually. ESA and UK agree to establish an Ariane telemetry station on Ascension Island. The mothballed shuttle pad at Vandenberg will be converted for Titan 4 launches. The USAF would have preferred to build a new Titan pad, but Congress balked at the price tag. [From Flight International, 31 Jan:] NASA places firm contract for launch of Mars Observer on Commercial Titan in Sept 1992. McDonnell Douglas starts development of the Aeroassist Flight Experiment on NASA contract. It will fly the first operational test of aerobraking. In May 1994 it will go up on Endeavour, fire a solid-fuel motor to drop its orbit into the atmosphere, fly an aerobraking pass, and then boost itself back up into orbit for recovery by Endeavour. Soviets plan a second-generation materials-processing satellite [the US having yet to build a first...], the Nika-T series, to fly first in 1993 aboard the Zenit booster. It will be heavier than the current Photon series, and will include solar panels to permit a 120-day mission (as compared to Photon's 16 days). The return capsule will have nearly triple the current 450kg capacity, although it will continue to be based on the Vostok capsule (which first flew as Sputnik 4 in 1960). [From the 26 Jan issue of Science:] Preliminary results from the Cosmic Background Explorer are in, and there is good news and bad news. The good news is that COBE has decisively shot down Berkeley/Nagoya sounding-rocket data which had suggested that the cosmic background might be warmer than a black body at some infrared wavelengths that cannot be seen from the grond. Such extra warmth would have required "the tooth fairy" to explain it. However, COBE reports that the cosmic background is essentially a perfect black body at a temperature of 2.735 K. The bad news is that the theorists have been hoping to see variations in the background from one part of the sky to another, which would reflect the early density variations that eventually turned into clusters of galaxies. Unfortunately, with preliminary results for 75% of the sky, COBE reports no variations whatsoever. If this persists over the full sky with more-accurate later results, the theorists are in trouble. (They are already having some other difficulties, but this would make it much worse.) [And from the 2 Feb issue of Science:] The standard explanation of meteorites is that they are debris from the asteroids. This is convenient in that it gives us samples of asteroidal material, albeit very poorly documented ones. The most common type of meteorites, the ordinary chondrites, are thought to be derived from the common type S asteroids. The material in ordinary chondrites seems to be primitive material from the early solar system, never exposed to major heating. Unfortunately, the spectroscopists have announced strong evidence that the type-S asteroids are too metal-rich to be primitive bodies in general, and to be the source of the ordinary chondrites in particular. Confusion reigns: where can the ordinary chondrites possibly be coming from? There is some hope that the first Galileo asteroid encounter, with Gaspra in Aug 1991, might shed some light on asteroidal geology: Gaspra is type S. -- MSDOS, abbrev: Maybe SomeDay | Henry Spencer at U of Toronto Zoology an Operating System. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 5 Mar 90 21:39:35 GMT From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ames.arc.nasa.gov (Ron Baalke) Subject: Galileo Update - 03/05/90 GALILEO MISSION STATUS REPORT MARCH 5, 1990 The Galileo spacecraft is 50,374,030 miles from the Earth, 6,720,180 miles from Venus and was travelling at a Heliocentric velocity of 90,480 miles per hour. Galileo is in cruise mode-dual spin with a spin rate of 3.15 rpm as measured by its star scanner. The spacecraft's attitude sun point angle is at 0.5 degrees. Perihelion occurred on February 25. Round trip light time is 8 minutes, 54 seconds. Several SITURNS to lead the sun were successfully performed on February 24, 26, 28 and March 2. Subsequent to the SITURNS performed on February 24 and 26, the attitude control system successfully completed a planned spin detector calibration. This calibration activity commanded the spacecraft from the initial dual-spin mode to all-spin and then back to dual-spin. The spacecraft performance was as expected throughout the calibration activity. Several changes were made to the star sets already on board in the Venus-Earth-1 (VE-1) sequence load. Changes were made to star sets on February 28 and March 2 to maximize the likelihood of successful star acquisition. The star updates were made after attitude control identified serious concern with the on-board star set. Prior to loading the new stars, extensive analysis and testing was performed. Attitude control star analysts have completed testing of the remaining stars in VE-1 beyond March 6. All tests were successful; no further star updates in VE-1 are required. Commands were sent on February 26 to change the attitude control parameters associated with the star scanner bright body avoidance. The parameter change reduces the half-cone angle stray-light field of view from about 50 degrees (set at Venus) to about 30 degrees. This change allows the star scanner to safely and reliably detect the required stars in the remainder of the VE-1 sequence through March 26. On February 26 the system fault protection software was changed to command selection of the Low Gain Antenna-1 (LGA-1) in the event of execution of the command loss algorithm. Actual switch from LGA-2 to the LGA-1 is scheduled for March 12. Performance over the LGA-1 is acceptable for both command and telemetry as early as March 9. Telemetry performance will be limited to 10 bps from March 6 thru March 25. Cruise Science memory readouts were successfully performed for the EUV, DDS and MAG instruments as planned. AC/DC bus imbalance measurements remain relatively stable. The AC measurement has varied between 47 and 48.5 volts while DC measurement has varied between 21.3 and 21.6 volts. All other power-related measurements (bus voltages, currents, shunt current) and other subsystem measurements have all been as expected. On February 24 the Command and Data Subsystem (CDS) telemetry indicated that a despun Critical Controller (CRC) Power on Reset (POR) had occurred. No similar indications were evident elsewhere in the CDS. In fact, all other CDS telemetry indicators were as expected. The POR signal is generated by the CDS power converter and sent to the corresponding Hardware Command Decoder (HCD), and/or spun and despun Critical Controller Circuitry (CRC). The POR signal is normally generated when either power converter detects a low voltage condition for several tens of microseconds. No interruptions in processing or loss of functionality were observed. Once a despun CRC POR indication is received the logic circuity in the CDS holds that state (via a latch device) until it is reset by ground command. Upon completion of initial anomaly analysis, several real-time command troubleshooting actions were taken on February 28 and March 2 to determine whether the POR signal was still present and to reset the POR bit. The first action verified that the CRC POR bit was still "set" as expected. The subsequent actions on March 2 POR successfully reset the POR bit and that the POR related logic circuitry is functioning properly. The success of these actions provides confidence that the critical controller circuity and telemetry circuits which monitor this function are working properly. The exact cause of this anomaly is unknown and its implications are presently being assessed. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | ------------------------------ Date: 6 Mar 90 01:53:59 GMT From: zephyr.ens.tek.com!wrgate!mrloog!dant@uunet.uu.net (Dan Tilque) Subject: Space capsules (was Re: space news from Jan 22 AW&ST) henry@utzoo.uucp (Henry Spencer) writes: > >The G.E. proposal is explicitly a minimal scheme, not an "absolutely first >class" [translation: gold-plated] one like NASA's. Major points of note: > > - Reliance on existing technology. "The thing we plan to do > use existing technology in forms and integrations that can be > demonstrated on Earth in 2-3 years at a cost of $50-150M." > No new launchers: hardware goes up on Titan 4s and Deltas, > people on the shuttle or in Apollo-type capsules, with use > of commercial launchers a possibility. 24 launches in 10 years. I'm not sure that Apollo-type capsules can be considered existing technology, unless they're Russian capsules. Also, I don't think any of the current expendables are man-rated (I'm sure someone will correct me if I'm wrong). However, they could probably build a capsule for, say 4 people, which could go up manned in the shuttle payload bay. If they equip it with retros, shielding and a parachute, it could double as an emergency return vehicle. --- Dan Tilque -- dant@mrloog.WR.TEK.COM ------------------------------ Date: 6 Mar 90 14:23:22 GMT From: samsung!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!uxh.cso.uiuc.edu!jep@think.com (John E. Prussing) Subject: Re: Rocket Info In article <14446@s.ms.uky.edu> jkolasa@ms.uky.edu (James Kolasa) writes: > >I'm preparing a simple programming assignment for my students and I wonder >if someone could give me some figures. Does anyone have a rough estimate of >mass of a rocket (esp. Saturn V)? How about fuel capacity? How about >a conversion factor between kilograms of fuel and thrust (in Newtons)? >-- >-- James Kolasa | "Computers are so naughty, -- >-- 121 Moloney, L.C.C. | I could just pinch them" -- >-- Lexington, Ky. 40506-0235 | -The Martian -- >-- jkolasa@ms.uky.edu {rutgers,uunet}!ukma!jkolasa jkolasa@UKMA.BITNET -- The thrust of a rocket engine is equal to the PRODUCT of mass flow rate The thrust of a rocket is equal to the PRODUCT of mass flow rate (kg/s) times exhaust velocity (m/s). There is no direct conversion between kg of propellant and thrust. A modern chemical rocket has an exhaust velocity of about 4400 m/s. The shuttle main engines (of which there are 3) each have a thrust of 1.7 x 10^6 N, and the solid rocket boosters (of which there are 2) each have a thrust of 12.9 x 10^6 N. From the thrust values and exhaust velocity given, you can determine the required mass flow rate. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- John E. Prussing Internet: jep@uxh.cso.uiuc.edu Aeronautical & Astronautical Engineering University of Illinois at Urbana-Champaign Bitnet: jep@uiucuxh ------------------------------ End of SPACE Digest V11 #120 *******************