Recent years have seen an increase in efforts to design, build and operate small satellites in laboratories all over the world. These micro satellites provide number ous flight opportunities for science experiments at a fraction of the cost of traditional larger missions.
Micro satellites are transforming the space business the same way as personal computers changed the computing industry in the 1990s. With make space technology more accessible for a larger and diverse number of users.
While small satellites have been around since the dawn of the Space Age, large satellites and programmers have dominated the industry. Now, major advances in microelectronics
Have made smaller satellites a viable alternative.
Inspired by the flight patterns of migrating birds, microsatellites would be able to fly in close formation. These are versatile, quick to build, reliable and much cheaper then the traditional optional satellites. Despite their small size and weight (50 to 100kg), these carry a wide range of payloads, including satellite communication, space science, and remote sensing and in-orbit technology demonstration payloads, for both civilian and military purposes,
Space companies are working on even smaller ‘Nano’ and ‘Pico’ satellites. The launch cost of microsatellites is less for these can ride piggyback on larger satellites.
Micro satellite images are being used in remote sensing applications including:
1. Environmental change and disaster monitoring.
2. Cartography for civil engineering and town planning.
3. Forestry and habitat mapping.
4. Offshore pollution monitoring for government agencies and oil companies.
The microsatellites would orbit as close as 10 meters from each other and open new opportunities for orbital research. Because they weigh very less, the diminutive crafts cost much less to launch and consume less fuel once aloft. By combining several smaller satellites, the combined system wills have greater flexibility and power than a single traditional satellite.
WHAT MICROSATELLITES CAN DO?
Communications. At a time when satellite communications were synonymous with larger geostationary satellites for transparent real-time wideband services, proposing the use of low-earth orbits for communications was considered a somewhat retrograde step. However, the close proximity of the satellites in LEOs to the user and the consequent reduction in transmission loss and delay time are big attractions—holding out the promise of less expensive ground terminals and regional frequency reuse.
Nevertheless, the communication characteristics associated with a LEO constellation pose quite different and demanding problems, such as varying communication paths and links, high Doppler shifts and handover from satellite to satellite.
Microsatellites pioneered the use of early internet techniques to provide worldwide, non-real-time, digital date store-and forward-email connectivity, especially in remote areas where the telecommunication infrastructure is inadequate or not-existent.
SPACE SEIENCE:- Microsatellites can offer a very quick turnaround and inexpensive means of exploring well-focused, small-scale science objectives or providing a proof-of-concept prior to the development of large-scale in strumentation in a fully complementary manner to expensive, long-gestation, large-scale space science missions.
This provides opportunities for young scientists and engineers to gain real-life experience of satellite and payload engineering for later large-scale missions and initiate a programmed of research, and retrieve orbital data for analysis and presentation for a thesis.
TECHNOLOGY VERIFICATION:- Microsatellities are also an attractive and low-cost means of demonstrating verifying and evaluating new technologies or services in a realistic orbital environment rapidly and within acceptable risks prior to the commitment to a full-scale, expensive mission. For example, satellites depend upon the performance of solar cell arrays for production of primary power to support on-board housekeeping systems and payloads throughout their seven to 15 years of operational lifetime in orbit.
EARTH OBSERVATION:- Conventional earth observation and remote=sensing satellite missions are extremely costly---$500 million is not unusual. Therefore there are relatively few such missions undertaken and the resulting data, whilst providing impressive spatial and spectral resolutions, yields poor temporal resolution of the ground targets due to the small number of these spacecrafts actually in the orbit.
Microsatellites have brought about a revolution in observation of the earth from space. High-density, two-dimensional, semiconductor charge-coupled device (CCD) optical detectors , coupled with less-power consuming yet computationally powerful microprocessors, present a new opportunity for remote sensing using inexpensive small satellites.
MILITARY APPLICATIONS: Demands for military-style satellite procurement and a cost-effective approach to microsatellite engineering might at first sight appear incompatible. However, whilst retaining the essential characteristics of low cost and rapid response, a military version of the microsatellite platform with deployable solar panels has been developed to support various military payloads. The ‘commercials’ and ‘military’ platform versions differ in the specification and procurement of components, particularly in the amount of paperwork that traces hardware and procedures.
Trade-off between the constraints of a military programme and economy has been sought that increases the cost and timescale by a factor of around 1.5 compared to the commercial microsatellite procurement process.
BEBEFUTS IF MICROSATELLITES:- Direct benefits from the use of small satellites may be identified depending on their field of application. However, those benefits result from an application that could also be provided by larger spacecraft. Small satellites provide their own contribution in the following areas:
1. Improvement of agricultural and animal productivity in medium to large size frames owing to better weather predictions, identification of soil characteristics, improvements in communication and transportation.
2. Lowering of transportation costs, made possible through optimization of truck, bus and ship routing, and location and early robbery detection, with favorable impact on the price of goods.
3. Provision of communication for the basic needs of small rural settlements in remote areas
4. Improvements in natural disaster detection and relief, made possible by systems that integrate scientific, communication and remote sensing satellite networks
5. Educational programmes for people in remote areas.
NASA’S SMALL SPACECRAFT
The Small Spacecraft Technology initiative of National Aeronautics and Space Administration (NASA). USA. Aims at advancing the technologies for reducing the cost and the time of getting civil and commercial space missions from the drawing board to orbit. The programme follows new approaches to satellite design and development that will not only significantly lower the cost but also permit the builder to incorporate commercials standards in the design and qualification process. Thus, it will serve NASA’s needs by allowing more frequent space missions within lower budgets, and enhance the competitive edge of US Space system manufacturers in the global market.
The programme was launched in 1994 with the awards of contracts to two industry eans for development of ‘ smallest’ of lightsats’ in the 272-480 kg class. The small satellites are designed to cater to a wide range of missions through use of standard hardware and software adapted to various applications.
