SEMINOR ON IT IN SPACE

Submitted By: Y.Naresh M.C.A (|III semester) Roll no: Y4MC14009

Submitted To: Department of Computer Studies Mahatma 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 always served 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, have first been tried out of the moon. Like in most other areas, space research is also moving into larger-scale simulations using powerful computers . in fact given the high cost , and often the impracticability of conducting live experiments, space research had moved into computer-based simulation long before most other streams. Everything from flight paths of futer rockets to the theories on the origin of the universe and its evolution are today computer simulated.consider the case of the magnetic file around a planet. Like with everything else in space research . let take the moon as our example the moon’s magnetic field is very feeble when compared to that of the earth. Also unlike on the earth, it varies widely from point to point. This much is known 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 core like what the earth has, but has localized magnetic sources. What, during the course of the moon’s evolution, could have caused this? This is where computer simulation can provide an answer. And an answer has been recently found. Reaearch at the university of California, Berkely, have modeled a blanket of dense material that would briefly insulate and even heat the lunar core, before bobbing to the surface to allow a brief period of rapid heat flux and core convection The calculations were run on Cray T3-E 1200 located at NASA’s Goddard space flight center in greenbelt, MD which was taken offline at the end of last year. We performed the final calculations last spring on 128 processors of the Cray. We were running case of about 20 GFlops for 10 hours each. We ran about 10 cases for our final results. The software is our (written in Fortran) which uses MPI and has been developed over the past 15 years, primarily by John Baumgardner at Los Alamos National Laboratory. It is portable and has run on every operating system. We are currently running it on Beowulf clusters running Redhat linux and also on the earth simulator in Japan, which uses HPUX. The machine at NASA Goddard ran a flavour of Unix. The software was developed for modeling the earth’s interior, but has also been applied to mars and the moon. One of the basic tents of space research is that projects could take many, many year to reach completion. About this specific problem, stegman says the problem was first looked at 15 years ago by BAUMGARDNER. Recent technical 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 and the earth, using what we have learned about the moon. Fortunately, we now have access to 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 has before. 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 being mars, to be followed by Jupiter and its moon, europa. This idea of talking the internet to the space comes from the need for a low cast and high reliability inter planetary network. It is not that there was no communication earlier.when Countries started sending probes into the space,each used a unique set of protocols to communicate with the earth. This was done using the deep space network(DSN) developwd by NASA. Since these probes communicated with same ground stayions, the need for common protocol increased with time. Taking the internet to space is the offshoot of this need for standardization. The inter planetary network(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 work on the earth because of its fixed size and the fixed positions on which the data has to travel. Now, for the implementation on the planets will be connected through individual dedicated getways. The individual networks can follow their own protocols,but these protocols will end at the gateway. By keeping the internets of all the planets separate,engineers will not have to make long service calls. Besides they will not have to send a database of 20-million dotcom names to mars periodically These gateways will work on a bundle based protocol, which will reside over the transport layer to carry data from one gateway to another. This gateway may not be on the surface of a planetary body;it can be a spacecraft in orbit,too.At at the moment a bundle protocol will be needed because the data will need to travel huge distances,and sending small packets of data may not be feasible. Instead, this data will be collected and sent 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 bigger marssat acting as a gateway to the earth. Managing the individual planet internets is not a big 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 the biggest effort. The use of standarda-based technology in space will mean that the commercial vendors can be used to provide the equipment, which will drastically decreases the equipment and manpower cost needed in space communication. Sounds too good to be true?well,there are thorns to content with too. At the moment the communication links from the space to yhe earth are very cumbersome with three satellite clusters placed around the world. The biggest problem is the bandwidth. Thw other biggest hindrance is the astronomical distance between the two planets. This can result in long delays,for example, a round trip transmission from earth to mars may exceed 40 mins. Even if the distance is managed there can be instance when the communication 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 hacker community,which is quite strong on our planet. One this kind of technology is functional,its security will be a big issue.

Satellite Tracking

Today there are more than 5,000 satellites in our space . These are kept track of by telemetry and control systems. October 4 1957 Sputnic the first artificial earth satellite was launched by the USSR, and thus began the space age. Now , 45 years after, there are more than 5,000 satellites in outer space,and tracking and controlling them is big work. Thousands of observatories, computers,communication systems and human beings work round the clock,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 oceans from outer space using artificial satellites, and monitoring the performance and condition of 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 the spacecraft’s condition in outer space and able to control it from the ground. This processing has to be done in real time using real time systems . this means developing high performance and robust systems that will work in extreme conditions and constraints of space, weight and power in satellites. Earth stations, too , demand a high degree of expertise and planning while developing such systems. A basic telemetry system consists of s measuring instrument, transmitter and receiving station. The measuring instruments are sensors that measure the amount of a physical attribute and transform the measurement to an engineering unit value. This is multiplexed as a single data stream, formatted and then transmitted using radio or microwave signals . Hence measurements can be made at remote or inaccessible spots, and the data 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 enormous amount of data received and presents it in a user-friendly manner to the operators. They use a variety of display objects-like strip charts, bar charts, vertical maters, crossplots and analysis programs like excel or high level analysis, languages to evaluate archived data,extract results and generate repports. A satellite’s conditions is also monitored in real time so that decisions regarding its operation and path can be taken instantaneously in case of a problem. The display systems run on both UNIX and PC platforms. The communication systems for interfacing with ground stations network and the real time processing of satellite data generally use UNIX. The communication system uses TCP/IP protocol for data transfer between computers on the ground station networks. The data is stored on disks or tapes as files, but other alternatives are relational database like MS Access and oracle schudling system generate operation schudles and allocate network resources 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 some from www.netacquire.com. In India the ISRO telemetry tracking and command networks does these. It provides mission support to satellites and launches vehicle missions, and has a network of ground stations across the country and abroad that provide valuable inputs for controlling India satellites.

Hubble control systems

The hubble space telescope(HST) is a large optical telescope. It orbits the earth and takes detailed pictures of stars,galaxies and solar-system objects..where ever is out there.The HST uses an elaborate spacecraft-management system to keep it afloat and working.In this respect, it is nodifferent from other spacecraft.The main elements of the system are the computer support system module and the advanced tracking and data relay satellite(TDRS)series.The computer support system module contains devices and systems needed to operate the hubble telescope.This serves as the master control for communications, navigation,power management,etc.The TDRS series accepts Hubble’sInformation for relay to the ground controllers at the space telescope operations control center(STOCC) in greenbelt,Maryland,us.Similarly,the TDRS also provides high band width communication support to the international space station(ISS) and some other satellites up there 7000 variables of real time information from the hubble telescope are transmitted to the geo-synchronous tracking and data relay satellite system(TDRSS),from which they are downlinked to the ground station at white sands,new Mexico,and then relayed to the Goddard space flight center in Maryland using what is known as the comtrol center system(CSS).Further data analysis is done using the space telescope science data analysis system(STSDAS).The ccs front-end uses java applets that let engineers control and monitor hubble from the earth.The ccs user interface has two parts:The first is control,where the telescope can be commanded to select new targets;and the second is data visualization,where the user can view telemetry and engineering 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,where a middleware serever connects to the exciting server system.This allows anyone with access privileges on the internet to view the engineering data is being continuously transmitted by the spacecraft, and even to obtain a personalized,configurable view of this data.the server code written in c++. The ccs is used to handle communication between hubble and the ground stations for spacecraft commanding and health and safety analysis. The architecture for this is a typical secure network.The data sent from telescope is analyzed using the STADAS,which is powerful set of tools that support software used to calibrate and analyze data.A companion package,tables ,is a set of tools for creating and manipulating tabular data,reading and writing flexible image transport system(FITS) the widest used data format used for astronomical images –immages and tables,and creating customizex graphics.STADAS and TABLES are layered on the image reduction and analusis facility(IRFS) software from the national optical astronomy observatories.STADAS and TABLES run in tandem with IRAF. The space telescope engineering data store(STEDS) isintended to serve as a common data source for all the telemetry data for all the hubble subsystems.its design uses a typical middleware-enabled three tire model,and it is plat from independent as it has to be accessed over the internet.The telemetry data stream from hubble is transferred to the front end processor(FEP) vis nascom.Fep provides a communication interface

between the vehicle and ground control and captures all the downlinked data.It then for forwards 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 SPACECRAFT

COMPUTING FOR SPACE SHUTTLE AND PATH FINDER

SHUTTLE 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, they are allApart of the space shuttles avionics systems the lifeline of the shuttles wayback in 1988.Other data processing systems consist of five general purpose computers mass storage, a time shared computer data bus network for communication between the computers. AS of all five GPCs were IBM AP-101S computers.Before that they were the IBM AP-101Bs. The older GPCs had non –volatile memory ,but with the AP 101s the shuttle computers moved to volatile memory with battery back up.Each of the GPCs consists of a central processor. Unit and an input /output processor.the first four systems comprise thePASS[primary avionics software system] it may seems surprising that NASA uses ancient computers, but they do so because of a very reasons; these computers have been thoroughly tested .such reliability is extremely necessary when dealing in mission-critical operation. GPC is loaded with different soft war created by adifferent coany but performing the same functions and operation. This software is the Backup Flight system[BFS]. The BFS monitors the other GPC to keep track of the current state of the vehicle . if required the BSF can take over control of the vehicle upon the press of a button . theBSF also performs the system management functions during ascent and entry .BFS software is always loaded into the fifth before flight but any of the five GPCs could be made the BFS GPC if necessary .NASAis developing shuttle upgrade project to install a vehicle health monitor [VHM] system.the VHM system will be used to detect troubleshoot and resolve hardware problems during and after fight .to match the hardware the software is also written and verified meticulously.the shuttle control software has some 420,000 lines of code.the software is subject to countless hours of verification and testing.yet, there are flaws.ther are still bugs in the code but when compared to other software they are very less.thetwo companies involved in the shuttle software creation were IBM Federale systems and Lockheed Martin.When information and voice is scrambledfor security so there is a computer onboard to decrypt this data so that the astronauts can read it or herd the voice from mission control in Houston, Texis.once the data is decrypted there are other computersonboard that controle the attitude ,

velocity ,temperature,and toilet/bathroom systemjust to name a few.Acomputer called the ground communication logic controller[GCIL] receives this data and then routes it to the appropriate computer system to perform one of this function .Houston , Texas controls most of the computers onboard from the grond itself because the crew has experiment and science data to collect and sometimes cannot be responsible for all functions. PATHFINDER The path finder mission that put a rover,sojourner of mars was conceptualized in 1992. Traditionally, spacecraft landed on alien territory by the means of 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 airbags as suspension. Given the distance mars from the earth, the timetaken by the signals from nars to reach the earth is about 10 mins. It was launched on December 4, 1997 abd, after nearly seven months of space travel reached mars. The path finder mission also carried a rover, soujourener to mars. The payload also included an alpha proton X ray spectrometer to 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; some amount of autonomous control had to be built into the system. After landing it took another 2 martin days to get the rover functional and it remained so for the next three months. During these three months sojourner sent back over 2.6 billion bits of data. It also did 20 soil analysis tests during this time the computing power behind the rover is a radiation protected IPM RISI 6000 single chip CPU. The complete mars path finder flight computer had 128 MD DRAM. The code was developed using Vx works as the real time OS and the good old C and assembly for coding. The communication between the lander and the rover is not exactly rocket science. The protocol using a simple acknowledge/negative acknowledge algorithm(where the data was received or not). A CRC check is done on the receiving side to validate the transmission. The maximum frame size used was 256 bytes. Such methodology 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 for some time now. Originally, they were the purview of the military some of the better known satellites known that are used for this purpose are IKONOS which captures 1-meter resolution images, the INSATAs, the US landsat canadas RADARSAT and the European space agency’s ERS satellites. These are archived and distributed in various formats. We may be familiar with some of these formats, while some are specifically developed to handle extra information. For browsing, common formats-GIF and JPEG-are used. But for archiving the data, the files are stored on digital linear tapes(DLT) in the framed raw expanded data format(FRED). This raw image format is considered a ture ‘digital negative’, which records 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, images are stored in formats that can also provide lots of additional information.

Superstructure Format: this is one such format, developed by the landsat ground station operators working group (LGSOWG). The committee for earth observation satellite (CEOS) has adopted it to exchange data between different users. The superstructure format has the provision to include ancillary data pertaining to the image file, like mapping or other geographic information, and hence is most suitable for applications where further processing has to be performed on the images.

GeoTIFF: this enhanced version of TIFF contains all the information necessary for converting the iamage co-ordinates to geographic and cartographic co-ordinates.

DIMAP with GeoTIFF: digital image MAPping is a metadata format designed to document to document digital image maps using XML. The underlying image format is GeoTIFF. Spot image, satellus and CNES ( the French national space agency) have developed DIMAP. It is and open initiative. Any one can contribute modifications to the format.

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 one after 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 digital imagery used by the intelligence community, the department defense, and elated departments and agencies of governments.

Flexible image transport system (FITS) is an archive and interchange format for astronomical data files. Originally designed for transfer of images, FITS is now widely used as an astronomical data transfer format.

SPACE COMMUNICATION PROTOCOLS

Earlier satellites used customized systems for communication with each mission or set of missions being more or less self-contained, and no one thought of interpretability with other systems now as the cooperation among the agencies and nations grow, interpretability becomes important. Recognizing the fact, NASA, US defense department and national security agency of the US have jointly designed specified, implemented under testing a set of protocols called space communications protocols standards (SCPS). The SCPS suite currently has four modules : file handling, transport, security and network. Instead of being an entirely new system, it is a new version of the existing standards (TCP/IP, file transfer protocol ) optimized for wire less networks and satellite links. 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 covers layers three and four of the OSI model and the IP and TCP layers of the TCP/IP protocol suite.

SCPS-File protocol (SCPS-FP): File transfer protocol coordinate the movement of files between systems. SCPS-FP is derived from FTP with extensions to support the movement of file records, addition of integrity checking, and resume support after interruption.

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 as SP3/NLSP, IETF IP security.

SCPS-network protocol (SCPS-NP): Network protocol route data through the intermediate systems to the destination. It functions as the IP (internet protocol ) with the additional capability of supporting both fixed routing and connectionless routing of packets through space and wire less data link. SCPS-NP also offers multiple routing options and supports packet life time control.

SCPS-transport protocol (SCPS-TP): Transport protocol support end to end communications between systems ie, systems active only at end points and not intermediate routers. SCPS-TP is the most prominent part of the protocol suite since it gives major performance improvement in the space environment. SCPS-TP is a modified version of TCP (transmission control protocol) but the terrestrial environment for which TCP 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 long delay, high bit-error rate environments of satellites with a performance improvement by a factor 10 and more.

READY FOR THE COUNTDOWN

A satellite launcher like the PSLV as thousands of subsystems that have to system properly for a launch to be successful. These rocket systems are monitored by embedded systems. As countdown to lift off approaches, all of these have to be monitored and decisions on weather to continue with the launch or to abort need to be taken in real time. For this real time, embedded systems find extensive use in pre-launch check out systems.In the case of launch agencies like ISRO, they independently create the checkout software required to run launcher systems and rockets are expand on the work of collaborating agencies. In the case of launch agencies like Ariane, the check out systems could be developed by third party contractors. For example the checkout systems for the Atlas V rocket were done by L-3 communications. The amount of information picked up by these systems is too much and too complex to be comprehended in their alphanumeric form, or by one person. So the data is distributed over a network to many controllers, who view the information graphically. Change in parameters would be indicated in a change of parameters or colors and 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 in mathematics. Both astronomy and mathematics have their roots in antiquity and all ancient civilizations have been fairly advanced in booth these sciences. So a study of the ancient texts, particularly in astronomy from different civilizations , may be worth the while for any one with more than a passing fancy in the space sciences. The Aryabhatiyam, written around 499 AD, is perhaps the oldest these. This mathematical –astronomical treatise of 121 sloaks is supposed to be surprisingly accurate in its calculations when compared to measurements made possible by modern instruments. If ancient llanguages are not your staple ,many of them are available in translations. And then there are many derived works and even the modern ones. Erich von Daniken’s Chariots of the gods is, of course the , the classic here. The spaceships of the prophet Ezekiel by Josef F Blumrich was with NASA and was involved in the design of the Saturn V rocket and Skylab . his book investigates the similarities in the biblical chariots seen by the prophet and modern-day space ships, and whether Ezekiel did indeed see alien spacecraft.

Costliest: June 4 1996 the first launch of Ariane 5. 40 sec after liftoff, the rocket broke up,taking down with it $500 million worth of launch vehicle and satellite(s). the enquiry commission appointed to look into the incident concluded that it was a software error. The interial reference system requires some computations done to align it till about 9sec before lift off. To avoid complications if a lift off is aborted, the computations continue till 50 secs after liftoff but are useless. This system was used in the ariane 4 series and was reused without rechecking in ariane 5. B ut ariane 5 had a completely different set of flight parameters, leading to an error being fed to the computations for the IRS, well into flight this error, in turn , made the IRS change the flight path of the vehicle drastically,leading to it disintegrating. Talk resuing software

Satellite: on October 22 2001 PSLVC3 took off form sriharikotha, successfully launching 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 is

hooked on to the internet . images taken by the cameras on PROBA will directly go to a web server at its controller center in Redu,Belgium. The images become directly available 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 server in 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 for routine 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 to deliver payload data to the ground.

Internet2: the world’s largest radio telescope at Arecibo , Pueto Rico sifts through 800 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-transmission requirements, 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 providing dedicated backbone connectively to academic and other research-intensive internet usage. The connection is 155 Mbps over a T3 carrier. One famous application of the Arecibo radio telescope is the SETI project, which uses it to monitor radio signals coming from space to search of extra-terrestrial life.

Traffic: if think that satellite are only for cutting edge work or for military uses, it is time for you think again. Computers can combine with satellite to perform some fairly mundane tasks also. Like monitoring traffic congestion. This was tried out by the European space agency between march 1999 and November 2002 in Rotterdam and Den Haag districts of Netherlands. A computer each was installed on to 15 postal service vehicles. Using GPS and a mobile communication system designed to communicate directly with satellites, data from these computers was transmitted to a central monitoring facility. This helped them in understanding traffic congestion patterns better than with traditional systems which measure traffic only at specific points along selected routes. There is no need for interaction between the driver and the computer in the vehicle. This method can be extended for fleet management , break down support, theft protection etc, based on a network of satellites.