Various ways of putting satellite in orbit
Various ways of putting satellite in orbit
JAKARTA (JP): Human-made satellites are usually lofted into space by expendable launch vehicles, or boosters. The vehicle or launcher is a rocket-powered vehicle launched from the Earth's surface or from an aircraft that can boost a satellite through the Earth's atmosphere and place it into orbit above the Earth or other planetary bodies. A launch vehicle typically has more than one stage of propulsive devices.
After ignition, a rocket lifts the launch vehicle and its satellite payload off the launch pad, imparting sufficient energy to overcome the effects of gravity. A second stage firing places the payload into a low altitude circular, or parking orbit.
Another rocket stage later sends the vehicle into an elliptical transfer orbit intended to deliver it to geosynchronous altitude.
More than 300 satellites are expected to be launched in the next four years.
The world's major launch vehicle manufacturers include Arianespace, a European consortium based in France, Lockheed Martin and McDonnell Douglas of the United States.
Arianespace is the manufacturer of the Ariane rocket family, which has entered its advanced generation, Ariane 5. Lockheed Martin is well-known for its Atlas rocket, which is also using a more advanced Atlas IIAR. McDonnell Douglas is the builder of Delta rocket.
Meanwhile, the China Great Wall Industries Corp. has entered the international rocket rivalry with its Long March rocket series. The other player in the race includes the Russian Krunichev (teamed with Lockheed) with its Proton rocket. On a smaller scale, there is the NPO Yuzhnoye of Ukraine with its Zenit rocket and Brazil with its VLS rocket.
Arianespace's new lifter, the Ariane 5, is scheduled make its maiden demonstration flight next month. The new rocket, which will first begin its commercial mission late this year, is designed to be more powerful and less complicated than the Ariane 4. The Ariane 5 will have just one main engine instead of four as with the Ariane 4. The advanced rocket will be able to carry nearly seven tons of payload, up from 4.5 tons. As a result, the Ariane 5 will be able to carry two satellites of nearly three tons, the weight for a common communications spacecraft.
Two satellites owned by Indonesia are scheduled to be launched by Ariane rockets. The Palapa-C2 is scheduled to be put on an Ariane 4 in May, while the Indostar-I will be launched by Ariane 5 next year.
At present, Lockheed Martin is also developing the Atlas IIAR, due to enter service in 1998. The new space launch vehicle will offer greater thrust than the current Atlas family -- the Atlas I, Atlas II, Atlas IIA and Atlas IIAS. The Atlas IIAS, the fourth generation and the most powerful in the Atlas family, was the launcher of Palapa-C1 in January 1996.
To face the more competitive launch market, McDonnell is developing the Delta 3, a new generation of the Delta boosters. Five of Indonesia's first and second satellite generations were lofted by Delta rockets.
In addition to advanced rockets, price is the strategy of the satellite launch players.
Sources said that a launch by the Ariane 4 rocket usually costs about US$100 million, depending on the number of satellites to be lifted off. An Ariane is able to carry two satellites per launch.
A launch by the Atlas rocket, which can only accommodate one satellite, usually costs $70 million.
China, meanwhile, has reportedly tried to undercut rivals by offering launches using Long March rockets for less than $45 million.
Michael R. Wash, president of International Launch Service, an affiliated firm of Lockheed Martin, admitted that launching costs were one of the most important things in grabbing customers.
Another major aspect for maintaining reputation and in winning the satellite launching market is the rate of successful lift- offs, as there is always a risk in any launch schedule.
A failure, especially marked with an explosion, will usually disrupt the following launching schedules. Such a failure will also halt users from using a destroyed satellite's transponders.
China Great Wall this year saw a launching failure at its Xichang launch site. A Long March 3B rocket, the newest of China's rockets which was on its maiden flight, exploded in a ball of fire and fell to Earth just 20 seconds after lift-off.
The incident destroyed the Intelsat 708, a three-ton satellite belonging to the International Telecommunications Satellite Organization (Intelsat), the Washington-based global telecommunications consortium. The satellite was worth about $200 million.
The accident on the 426-ton Long March 3B last month was the second in just over a year. It was China's fourth space accident within the last three years. In January last year, a U.S.-made satellite exploded 50 seconds after blast-off from the site.
The incident this year has caused cancellation to any other satellite launch scheduled to use the Long March 3B in 1996.
Recently, the Columbia space shuttle also failed to place an Italian satellite into orbit due to a botched tether. The $100 million Italian satellite was gone because of the incident.
One of Indonesia's satellites, Palapa-B2, was also lost in January 1984 shortly after being released from the Columbia. Fortunately, the spacecraft was found and brought back to the earth in November that year.
Meanwhile, an Ariane 44LP rocket failed to launch two satellites, Turksat1A and Eutelsat-2, in January 1994, causing a loss of about $356 million. In December that year, the Ariane 42P also malfunctioned and failed to launch PAS-3, a $150 million satellite owned by Panamsat of the United States.
The failures, all seven since Arianespace commenced its program in 1979, caused a rescheduling for the Palapa-C1 launching late last year. Indonesia, determined to have the Palapa-C1 in orbit on schedule, was then able to switch the satellite's launching to Lockheed Martin.
In the meantime, Lockheed Martin's Atlas rocket has had 21 successful launchings from July 19, 1993 to Jan. 31, 1996, when the country's Palapa-C1 was launched by Atlas IIAS. (icn)