ARGUMENTS over the control of geostationary orbital slots for Asian satellites grew more shrill this week as the Tongan associated Rimsat Ltd of Fort Wayne, Indiana, began the final stages of drifting a Russian satellite into a position where the Indonesian Palapa group has already parked one of its orbiters. Tongastar-1, a Raduga Gorizont satellite with three C-band transponders, or transmission channels, was due to arrive on station at 134 degrees east in an orbital slot 36,000 kilometres above the equator just off the northwestern coast of the Indonesian province of Irian Jayal this week. The disputed slot, however, already has the allegedly almost defunct 1983-launched Palapa B1 satellite at 134.1185 east in place, following a claim made on the slot by the Indonesian Government. The orbital position at 134 degrees east was formally awarded by the Geneva-based United Nations associated International Frequency Registration Board (IFRB) to the Kingdom of Tonga in 1988. But Indonesia, ignoring the IFRB ruling in February 1992, drifted its Palapa B1 into the disputed slot six months later. The IFRB, supporting the principle of ''first come, first served'' for registration, said Indonesia would have to switch off the Palapa or move it if there was any interference - if and when a Tongan satellite was placed at 134 degrees east. The island kingdom has appointed Tongasat, led by wild card entrepreneur Matts Nilson, as its agent. Tongasat, in turn, has contracted the US-based Rimsat and another US-based satellite operator, Unicom, to take up the six orbital slots Tonga has registered with the IFRB. Tongasat is reported to have three shareholders: Princess Pilolevu, the daughter of the King of Tonga, with 60 per cent of the equity along with Mr Nilson and a fellow American, Jerry Fletcher, who was at the centre of a controversy in the 1980s with a proposal to dump American toxic waste in Tonga. In six months the Russian Gorizont group is reported to be booked to launch a custom-built satellite for Rimsat. Five more satellites are set to follow to create an almost worldwide communications network. The total contract with Gorizont is thought to be worth in excess of US$150 million (HK$1.16 billion). Mr Nilson said the Jakarta Government was ''very blatantly and arrogantly ignoring Tonga's rights''. ''They seemed to think being first come, first served had priority. We have been planning to place a satellite at 134 east since we registered our claim with the IFRB five years ago. ''Then all of a sudden the Indonesians decided they should put a satellite there. Obviously it is grossly unfair that they think they have a right to do so.'' While Tongasat argues with Indonesia, it is also challenging the massive international satellite operator, Intelsat, a world-wide consortium of national telecommunications users. Tonga is protesting that Intelsat is planning to operate satellites close to Tongan slots. Last month the Tongan Government sent a letter to Intelsat director general Irving Goldstein complaining that Intelsat's proposed satellites at 69 degrees east and 85 degrees east would cause ''economic harm'' to Tongasat's slots at 70 degrees east and 83.3 degrees east. While the arguments continue between Tonga and Indonesia, the Thai Government is stepping into a turf dispute between the Bangkok-based Thaicom group and the locally-listed Asia Satellite Telecommunications Ltd (AsiaSat), the broadcaster of the STAR TV network signals. The Thai authorities are expected to make a formal protest to the British Government about Asiasat's plans to launch its powerful AsiaSat2 HS 601 satellite in early 1995 into 101.5 degrees east, just half a degree from the planned site for the weaker Thaicom-1 satellite, due for launch this December. According to international convention, commercial satellites are supposed to be placed within 2.5 degrees, or 18,750 kilometres, of each other or they cause mutual interference. A leaked draft letter to the British ambassador in Bangkok, Charles Adams, shows the Thai Government's displeasure. The row, which now seems to be developing into a political and cultural battle between Hongkong and Bangkok, took off when AsiaSat filed a claim to the 101.5 East slot with the IFRB in November 1991. But Thaicom had submitted documentation regarding the 101.0 degrees East slot, some months earlier. However, since the paperwork was incomplete, it was effectively ruled invalid. The Thais however, disagree. ''Thailand has no hesitation in asserting priority, actual and moral, to establish space systems in the proposed position at 101.0, having had it registered as early as 1990 and published by the IFRB - with notification distributed to all governments concerned, including the United Kingdom,'' the draft letter said. ''We must confess to being dismayed to learn that the only outcome from a series of meetings with AsiaSat, aimed at solving this co-ordination problem, were proposals by AsiaSat for Thailand to move her satellite network elsewhere.'' Certainly the powerful AsiaSat2 could almost overwhelm Thaicom1 once it is in place just half a degree away from the Thai satellite. AsiaSat's engineers say once AsiaSat2 is in orbit it will ''cause terrific problems'' because of the strength of its signal. But even if the less powerful Thaicom1 remains in its slot at 101.0 East it will also cause interference for AsiaSat2, say engineers. Gary Brooks, a member of the IFRB, was recently quoted as confirming that AsiaSat had registered ahead of Thaicom, adding that it was vital that members of the International Telecommunications Union, the IFRB's parent body, observe the regulations. If governments and private operators were not flexible, Mr Brooks said, the results ''could lead to anarchy as operators who get their satellites into orbit first try to jump the queue''.