SEMINOR ON IT IN SPACE Submitted By: Y.Naresh M.C.A (|III semester) Roll no: Y4MC14009Submitted To:Department of Computer StudiesMahatma Gandhi College (PG courses)Edulapalem, Guntur-522 019. FIGURING OUT OF THE MOON
If space has always been an enigma for mankind, then the moon has alwaysserved as the first post for any attempt at understanding or exploring deeper space.All ventures into outer space, ranging from exploratory fly-bys to managed flights, havefirst been tried out of the moon. Like in most other areas, space research is also movinginto larger-scale simulations using powerful computers . in fact given the high cost , andoften the impracticability of conducting live experiments, space research had moved intocomputer-based simulation long before most other streams. Everything from flight paths of futer rockets to the theories on the origin ofthe universe and its evolution are today computer simulated.consider the case of themagnetic file around a planet. Like with everything else in space research . let take themoon as our example the moon’s magnetic field is very feeble when compared to that ofthe earth. Also unlike on the earth, it varies widely from point to point. This much isknown from the measurements taken by spacecraft that flew by or landed on the moon.Now ,why is this so? The obvious conclusion is that the moon does not have a fluid corelike what the earth has, but has localized magnetic sources. What, during the course ofthe moon’s evolution, could have caused this? This is where computer simulation canprovide an answer. And an answer has been recently found. Reaearch at the university ofCalifornia, Berkely, have modeled a blanket of dense material that would briefly insulateand even heat the lunar core, before bobbing to the surface to allow a brief period of rapidheat flux and core convection The calculations were run on Cray T3-E 1200 located at NASA’s Goddardspace flight center in greenbelt, MD which was taken offline at the end of last year. Weperformed the final calculations last spring on 128 processors of the Cray. We wererunning case of about 20 GFlops for 10 hours each. We ran about 10 cases for our finalresults. The software is our (written in Fortran) which uses MPI and has beendeveloped over the past 15 years, primarily by John Baumgardner at Los AlamosNational Laboratory. It is portable and has run on every operating system. We arecurrently running it on Beowulf clusters running Redhat linux and also on the earthsimulator in Japan, which uses HPUX. The machine at NASA Goddard ran a flavour ofUnix. The software was developed for modeling the earth’s interior, but has also beenapplied to mars and the moon. One of the basic tents of space research is that projectscould take many, many year to reach completion. About this specific problem, stegmansays the problem was first looked at 15 years ago by BAUMGARDNER. Recenttechnical advancements allowed us to look at this problem again, beigining in mid 2000.the actual time spent working on the project was about 2 years. Where does it go from year we are thinking about the evolution of mars andthe earth, using what we have learned about the moon. Fortunately, we now have accessto even faster computers, which we have need in order to study these larger planets.Like they say in star trek, space exploration is about boldly going where no man hasbefore. And, it takes a computer to take you there. THE INTERNET ON MARS
The internet is slated to go over and above this world, the first target beingmars, to be followed by Jupiter and its moon, europa. This idea of talking the internet to the space comes from the need for a lowcast and high reliability inter planetary network. It is not that there was nocommunication earlier.when Countries started sending probes into the space,each used a unique set ofprotocols to communicate with the earth. This was done using the deep spacenetwork(DSN) developwd by NASA. Since these probes communicated with sameground stayions, the need for common protocol increased with time. Taking the internetto space is the offshoot of this need for standardization. The inter planetarynetwork(IPN),a part of jet Propulsion Laboratory(JPL),is managing this program. But how will this be implemented? One can plan how the internet will workon the earth because of its fixed size and the fixed positions on which the data has totravel. Now, for the implementation on the planets will be connected through individualdedicated getways. The individual networks can follow their own protocols,but theseprotocols will end at the gateway. By keeping the internets of all the planetsseparate,engineers will not have to make long service calls. Besides they will not have tosend a database of 20-million dotcom names to mars periodically These gateways will work on a bundle based protocol, which will reside overthe transport layer to carry data from one gateway to another. This gateway may not beon the surface of a planetary body;it can be a spacecraft in orbit,too.At at the moment abundle protocol will be needed because the data will need to travel huge distances,andsending small packets of data may not be feasible. Instead, this data will be collected andsent in a bundle, as a big burst of data,to the next gateway. Regarding mars, jpl plans to put many microsats around it and a biggermarssat acting as a gateway to the earth. Managing the individual planet internets is not abig problem as it can be managed in more or less the same manner as the earth’s network.It is developing The interplanetary backbone network(IBN),however, which requires thebiggest effort. The use of standarda-based technology in space will mean that thecommercial vendors can be used to provide the equipment, which will drasticallydecreases the equipment and manpower cost needed in space communication. Sounds too good to be true?well,there are thorns to content with too. At themoment the communication links from the space to yhe earth are very cumbersome withthree satellite clusters placed around the world. The biggest problem is the bandwidth.Thw other biggest hindrance is the astronomical distance between the two planets. Thiscan result in long delays,for example, a round trip transmission from earth to mars mayexceed 40 mins. Even if the distance is managed there can be instance when thecommunication is not possible at all when the planetsare on the opposite sides of the sun.Beside the natural factors of distance,we cannot overlook the potential of the hackercommunity,which is quite strong on our planet. One this kind of technology isfunctional,its security will be a big issue.
Satellite Tracking Today there are more than 5,000 satellites in our space . These are kept trackof by telemetry and control systems. October 4 1957 Sputnic the first artificial earth satellite was launched by theUSSR, and thus began the space age. Now , 45 years after, there are more than 5,000satellites in outer space,and tracking and controlling them is big work. Thousands ofobservatories, computers,communication systems and human beings work round theclock,around the earth, to keep their satellites in proper condition and on the right path.Telemetry, tracking and control are three major functions that make this happen. Satellite telemetry is measuring the conditions in the atmosphere and oceansfrom outer space using artificial satellites, and monitoring the performance and conditionof rockets, spacecraft and satellites that send information about their own performance,flight path and other data to earth. With this, the earth stations keep track of thespacecraft’s condition in outer space and able to control it from the ground. Thisprocessing has to be done in real time using real time systems . this means developinghigh performance and robust systems that will work in extreme conditions and constraintsof space, weight and power in satellites. Earth stations, too , demand a high degree ofexpertise and planning while developing such systems. A basic telemetry system consists of s measuring instrument, transmitter andreceiving station. The measuring instruments are sensors that measure the amount of aphysical attribute and transform the measurement to an engineering unit value. This ismultiplexed as a single data stream, formatted and then transmitted using radio ormicrowave signals . Hence measurements can be made at remote or inaccessible spots, and thedata collected is transmitted equipment for monitoring, display recording and analysis,On the ground, the receiving station receives the signals transmitted by the satellite,which are then sent for processing. The ground system makes sense of the enormousamount of data received and presents it in a user-friendly manner to the operators. Theyuse a variety of display objects-like strip charts, bar charts, vertical maters, crossplots andanalysis programs like excel or high level analysis, languages to evaluate archiveddata,extract results and generate repports. A satellite’s conditions is also monitored in realtime so that decisions regarding its operation and path can be taken instantaneously incase of a problem. The display systems run on both UNIX and PC platforms. Thecommunication systems for interfacing with ground stations network and the real timeprocessing of satellite data generally use UNIX. The communication system uses TCP/IPprotocol for data transfer between computers on the ground station networks. The data isstored on disks or tapes as files, but other alternatives are relational database like MSAccess and oracle schudling system generate operation schudles and allocate networkresources for satellites supported by the ground station. Web-based telemetry solutions enable such activities using a web browser ,and can be used from any machine on the ground system network. You can get somefrom www.netacquire.com.
In India the ISRO telemetry tracking and command networks does these. Itprovides mission support to satellites and launches vehicle missions, and has a network ofground stations across the country and abroad that provide valuable inputs for controllingIndia satellites. Hubble control systems
The hubble space telescope(HST) is a large optical telescope. It orbits theearth and takes detailed pictures of stars,galaxies and solar-system objects..where ever isout there.The HST uses an elaborate spacecraft-management system to keep it afloat andworking.In this respect, it is nodifferent from other spacecraft.The main elements of thesystem are the computer support system module and the advanced tracking and data relaysatellite(TDRS)series.The computer support system module contains devices and systemsneeded to operate the hubble telescope.This serves as the master control forcommunications, navigation,power management,etc.The TDRS series accepts Hubble’sInformation for relay to the ground controllers at the space telescope operations controlcenter(STOCC) in greenbelt,Maryland,us.Similarly,the TDRS also provides high bandwidth communication support to the international space station(ISS) and some othersatellites up there 7000 variables of real time information from the hubble telescope aretransmitted to the geo-synchronous tracking and data relay satellitesystem(TDRSS),from which they are downlinked to the ground station at whitesands,new Mexico,and then relayed to the Goddard space flight center in Maryland usingwhat is known as the comtrol center system(CSS).Further data analysis is done using thespace telescope science data analysis system(STSDAS).The ccs front-end uses javaapplets that let engineers control and monitor hubble from the earth.The ccs user interfacehas two parts:The first is control,where the telescope can be commanded to select newtargets;and the second is data visualization,where the user can view telemetry andengineering data either archived or being streamed down in real time from the spacecraft. The ccs applets establish a direct network connection to a NASA host,wherea middleware serever connects to the exciting server system.This allows anyone withaccess privileges on the internet to view the engineering data is being continuouslytransmitted by the spacecraft, and even to obtain a personalized,configurable view of thisdata.the server code written in c++. The ccs is used to handle communication between hubble and the groundstations for spacecraft commanding and health and safety analysis. The architecture forthis is a typical secure network.The data sent from telescope is analyzed using theSTADAS,which is powerful set of tools that support software used to calibrate andanalyze data.A companion package,tables ,is a set of tools for creating and manipulatingtabular data,reading and writing flexible image transport system(FITS) the widest useddata format used for astronomical images –immages and tables,and creating customizexgraphics.STADAS and TABLES are layered on the image reduction and analusisfacility(IRFS) software from the national optical astronomy observatories.STADAS andTABLES run in tandem with IRAF. The space telescope engineering data store(STEDS) isintended to serve as acommon data source for all the telemetry data for all the hubble subsystems.its designuses a typical middleware-enabled three tire model,and it is plat from independent as ithas to be accessed over the internet.The telemetry data stream from hubble is transferredto the front end processor(FEP) vis nascom.Fep provides a communication interfacebetween the vehicle and ground control and captures all the downlinked data.It then forforwards it to the attached all points archive, which interacts with the web server to
produce a web-browser output for a client machine,and through the middleware c++server to process the applet GUIs. CONTROLLING SPACECRAFTCOMPUTING FOR SPACE SHUTTLE AND PATH FINDERSHUTTLE 300 major electronic black boxes,300 miles of electrical wiring,120,400,wire segments, 6,491 connectors wiring and connectrs weight approximately 7,000 pounds,wiring Alone weighing approximately 4,600 pounds.seems daunting/ in fact, theyare allApart of the space shuttles avionics systems the lifeline of the shuttles wayback in1988.Other data processing systems consist of five general purpose computers massstorage, a time shared computer data bus network for communication between thecomputers. AS of all five GPCs were IBM AP-101S computers.Before that they were theIBM AP-101Bs. The older GPCs had non –volatile memory ,but with the AP 101s theshuttle computers moved to volatile memory with battery back up.Each of the GPCsconsists of a central processor. Unit and an input /output processor.the first four systemscomprise thePASS[primary avionics software system] it may seems surprising thatNASA uses ancient computers, but they do so because of a very reasons; these computershave been thoroughly tested .such reliability is extremely necessary when dealing inmission-critical operation. GPC is loaded with different soft war created by adifferent coany butperforming the same functions and operation. This software is the Backup Flightsystem[BFS]. The BFS monitors the other GPC to keep track of the current state of thevehicle . if required the BSF can take over control of the vehicle upon the press of abutton . theBSF also performs the system management functions during ascent andentry .BFS software is always loaded into the fifth before flight but any of the five GPCscould be made the BFS GPC if necessary .NASAis developing shuttle upgrade project toinstall a vehicle health monitor [VHM] system.the VHM system will be used to detecttroubleshoot and resolve hardware problems during and after fight .to match the hardwarethe software is also written and verified meticulously.the shuttle control software hassome 420,000 lines of code.the software is subject to countless hours of verification andtesting.yet, there are flaws.ther are still bugs in the code but when compared to othersoftware they are very less.thetwo companies involved in the shuttle software creationwere IBM Federale systems and Lockheed Martin.When information and voice isscrambledfor security so there is a computer onboard to decrypt this data so that theastronauts can read it or herd the voice from mission control in Houston, Texis.once thedata is decrypted there are other computersonboard that controle the attitude , velocity,temperature,and toilet/bathroom systemjust to name a few.Acomputer called the groundcommunication logic controller[GCIL] receives this data and then routes it to theappropriate computer system to perform one of this function .Houston , Texas controls
most of the computers onboard from the grond itself because the crew has experimentand science data to collect and sometimes cannot be responsible for all functions.PATHFINDER The path finder mission that put a rover,sojourner of mars wasconceptualized in 1992. Traditionally, spacecraft landed on alien territory by the meansof rockets(the Viking mission to mars). The path finder mission was a technological first,in demonstrating a low cost landing mechanism by the means of parachutes and airbagsas suspension. Given the distance mars from the earth, the timetaken by the signals fromnars to reach the earth is about 10 mins. It was launched on December 4, 1997 abd, afternearly seven months of space travel reached mars. The path finder mission also carried arover, soujourener to mars. The payload also included an alpha proton X ray spectrometerto anlyze the elemental composition of the soil on mars, to act like an on- site goeligist.As mentioned, the time lag for signals to reach the earth was around 10 mins. So; someamount of autonomous control had to be built into the system. After landing it tookanother 2 martin days to get the rover functional and it remained so for the next threemonths. During these three months sojourner sent back over 2.6 billion bits of data. Italso did 20 soil analysis tests during this time the computing power behind the rover is aradiation protected IPM RISI 6000 single chip CPU. The complete mars path finder flightcomputer had 128 MD DRAM. The code was developed using Vx works as the real timeOS and the good old C and assembly for coding. The communication between the lander and the rover is not exactly rocketscience. The protocol using a simple acknowledge/negative acknowledgealgorithm(where the data was received or not). A CRC check is done on the receivingside to validate the transmission. The maximum frame size used was 256 bytes. Suchmethodology is nothing but the more commonly used protocol striped to bare minimum. IMAGE FORMATS
Satellite images of the earth have been easily and commercially available forsome time now. Originally, they were the purview of the military some of the betterknown satellites known that are used for this purpose are IKONOS which captures 1-meter resolution images, the INSATAs, the US landsat canadas RADARSAT and theEuropean space agency’s ERS satellites. These are archived and distributed in various formats. We may be familiarwith some of these formats, while some are specifically developed to handle extrainformation. For browsing, common formats-GIF and JPEG-are used. But for archivingthe data, the files are stored on digital linear tapes(DLT) in the framed raw expanded dataformat(FRED). This raw image format is considered a ture ‘digital negative’, whichrecords data over a wider bit range (typically 10 or 12 bits) than JPEG or 8-bit TIFE.Satellite images are used for a variety of end uses, and to suit their requirements, imagesare stored in formats that can also provide lots of additional information.Superstructure Format: this is one such format, developed by the landsat groundstation operators working group (LGSOWG). The committee for earth observationsatellite (CEOS) has adopted it to exchange data between different users. Thesuperstructure format has the provision to include ancillary data pertaining to the imagefile, like mapping or other geographic information, and hence is most suitable forapplications where further processing has to be performed on the images.GeoTIFF: this enhanced version of TIFF contains all the information necessary forconverting the iamage co-ordinates to geographic and cartographic co-ordinates.DIMAP with GeoTIFF: digital image MAPping is a metadata format designed todocument to document digital image maps using XML. The underlying image format isGeoTIFF. Spot image, satellus and CNES ( the French national space agency) havedeveloped DIMAP. It is and open initiative. Any one can contribute modifications to theformat.Band Interleaved by line(BIL): this is one of the oldest format used for space imaging.It treats each line as separate storage units. The bright values for each line is stored oneafter another. It is practical to use this format if all bands in an image are to be used.National Imagery Transmission Format(NITF): This is a US standard per digitalimagery used by the intelligence community, the department defense, and elateddepartments and agencies of governments. Flexible image transport system (FITS) is an archive and interchange formatfor astronomical data files. Originally designed for transfer of images, FITS is nowwidely used as an astronomical data transfer format. SPACE COMMUNICATION PROTOCOLS
Earlier satellites used customized systems for communication with eachmission or set of missions being more or less self-contained, and no one thought ofinterpretability with other systems now as the cooperation among the agencies andnations grow, interpretability becomes important. Recognizing the fact, NASA, US defense department and national securityagency of the US have jointly designed specified, implemented under testing a set ofprotocols called space communications protocols standards (SCPS). The SCPS suite currently has four modules : file handling, transport, securityand network. Instead of being an entirely new system, it is a new version of the existingstandards (TCP/IP, file transfer protocol ) optimized for wire less networks and satellitelinks. So, to the end user, the new standard functions the same as TCP/IP.The SCPS addresses layers three through seven of the OSI model. Its major part coverslayers three and four of the OSI model and the IP and TCP layers of the TCP/IP protocolsuite.SCPS-File protocol (SCPS-FP): File transfer protocol coordinate the movement of filesbetween systems. SCPS-FP is derived from FTP with extensions to support themovement of file records, addition of integrity checking, and resume support afterinterruption.SCPS-security protocol (SCPS-SP): It operates between the transport protocol (SCPS-SP) and network protocol (SCPS-NP) and provides authentication, access control,integrity and confidentially. It uses a variety of existing security protocols such asSP3/NLSP, IETF IP security.SCPS-network protocol (SCPS-NP): Network protocol route data through theintermediate systems to the destination. It functions as the IP (internet protocol ) with theadditional capability of supporting both fixed routing and connectionless routing ofpackets through space and wire less data link. SCPS-NP also offers multiple routingoptions and supports packet life time control.SCPS-transport protocol (SCPS-TP): Transport protocol support end to endcommunications between systems ie, systems active only at end points and notintermediate routers. SCPS-TP is the most prominent part of the protocol suite since itgives major performance improvement in the space environment. SCPS-TP is a modifiedversion of TCP (transmission control protocol) but the terrestrial environment for whichTCP was designed is markedly different from that of space. As an example,Performance tests of SCPS-TP vs TCP-show that SCPS-TP is well suited to the longdelay, high bit-error rate environments of satellites with a performance improvement by afactor 10 and more. READY FOR THE COUNTDOWN
A satellite launcher like the PSLV as thousands of subsystems that have tosystem properly for a launch to be successful. These rocket systems are monitored byembedded systems. As countdown to lift off approaches, all of these have to bemonitored and decisions on weather to continue with the launch or to abort need to betaken in real time. For this real time, embedded systems find extensive use in pre-launch checkout systems.In the case of launch agencies like ISRO, they independently create thecheckout software required to run launcher systems and rockets are expand on the workof collaborating agencies. In the case of launch agencies like Ariane, the check outsystems could be developed by third party contractors. For example the checkout systems for the Atlas V rocket were done by L-3communications. The amount of information picked up by these systems is too much andtoo complex to be comprehended in their alphanumeric form, or by one person. So thedata is distributed over a network to many controllers, who view the informationgraphically. Change in parameters would be indicated in a change of parameters or colorsand other such graphical alerts or even audible alerts. Wisdom of the Ancients
space exploration has its origin in astronomy, which in turn has its roots inmathematics. Both astronomy and mathematics have their roots in antiquity and allancient civilizations have been fairly advanced in booth these sciences. So a study of theancient texts, particularly in astronomy from different civilizations , may be worth thewhile for any one with more than a passing fancy in the space sciences. The Aryabhatiyam, written around 499 AD, is perhaps the oldest these. Thismathematical –astronomical treatise of 121 sloaks is supposed to be surprisingly accuratein its calculations when compared to measurements made possible by moderninstruments. If ancient llanguages are not your staple ,many of them are available intranslations. And then there are many derived works and even the modern ones. Erichvon Daniken’s Chariots of the gods is, of course the , the classic here. The spaceships ofthe prophet Ezekiel by Josef F Blumrich was with NASA and was involved in the designof the Saturn V rocket and Skylab . his book investigates the similarities in the biblicalchariots seen by the prophet and modern-day space ships, and whether Ezekiel did indeedsee alien spacecraft.Costliest: June 4 1996 the first launch of Ariane 5. 40 sec after liftoff, the rocketbroke up,taking down with it $500 million worth of launch vehicle and satellite(s). theenquiry commission appointed to look into the incident concluded that it was a softwareerror. The interial reference system requires some computations done to align it till about9sec before lift off. To avoid complications if a lift off is aborted, the computationscontinue till 50 secs after liftoff but are useless. This system was used in the ariane 4series and was reused without rechecking in ariane 5. B ut ariane 5 had a completelydifferent set of flight parameters, leading to an error being fed to the computations for theIRS, well into flight this error, in turn , made the IRS change the flight path of the vehicledrastically,leading to it disintegrating. Talk resuing softwareSatellite: on October 22 2001 PSLVC3 took off form sriharikotha, successfullylaunching TES,PROBA and BIRD into space. PROBA weighs in under a hundred kilos,but it is unique in many ways. One of the unique factors about PROBA is that it ishooked on to the internet . images taken by the cameras on PROBA will directly go to aweb server at its controller center in Redu,Belgium. The images become directlyavailable to users from this web server, as soon as it comes in from the satellite.Webserver: UoSat-12 launched on april 21 1999 has the world first web serverin space . on jan 25 2001 HTTP was used to transfer data from the satellite to the ground.AIST-1 launched by the same company in December 2002 is the internet protocol forroutine in orbit operations AISAT-1 implements the CCSDS( consultative committee for
space data systems) CFDP(file delivery protocol), operating over an IP link at 8 mbps todeliver payload data to the ground.Internet2: the world’s largest radio telescope at Arecibo , Pueto Rico sifts through800 terabytes(819gb or 840 million MB) of data from deep inside the universe each day.It can gather 40 megabytes of data per second. To handle the enormous data-transmissionrequirements, it has been using a super high-speed internet2 connection since late 2001.Internet2 is an initiative to build quality of service into the internet by providingdedicated backbone connectively to academic and other research-intensive internet usage.The connection is 155 Mbps over a T3 carrier. One famous application of theArecibo radio telescope is the SETI project, which uses it to monitor radio signalscoming from space to search of extra-terrestrial life.Traffic: if think that satellite are only for cutting edge work or for military uses, it istime for you think again. Computers can combine with satellite to perform some fairlymundane tasks also. Like monitoring traffic congestion. This was tried out by theEuropean space agency between march 1999 and November 2002 in Rotterdam and DenHaag districts of Netherlands. A computer each was installed on to 15 postal servicevehicles. Using GPS and a mobile communication system designed to communicatedirectly with satellites, data from these computers was transmitted to a centralmonitoring facility. This helped them in understanding traffic congestion patterns betterthan with traditional systems which measure traffic only at specific points along selectedroutes. There is no need for interaction between the driver and the computer in thevehicle. This method can be extended for fleet management , break down support, theftprotection etc, based on a network of satellites.