The five astronauts aboard the space shuttle Challenger today orbited a $43 million satellite designed to forecast weather and vastly increase radio, television and telephone service for many of the more than 730 million people of India.

The event was of such international importance that it triggered a telephone call to the astronauts from President Reagan.

"I understand this will bring a broad range of communication and weather resources to the people of India and serve as a good example of international cooperation in space," Reagan said from his ranch outside Santa Barbara.

"On behalf of all our people, I want to thank you all for your courage and your commitment to space research," he said.

Reagan spoke to the crew of this eighth shuttle mission as Challenger passed above Hawaii at an altitude of 184 miles just after noon EDT. The call was relayed from California through a ground station in Hawaii.

The president said he wanted to extend personal congratulations to crew members Guion Stewart Bluford II, first black American to fly in space, and Dr. William E. Thornton, the oldest astronaut in orbit. At 54, Thornton is older by four years than any other astronaut who has flown in space.

"Congratulations, Guy," Reagan told Bluford. "You, I think, are paving the way for many others and are making it plain that we are in an era of brotherhood here in our land, and you will serve as role model for so many others and be so inspirational."

To Thornton, the 72-year-old president said: "You have an especially warm place in my heart. It makes me think that maybe someday I might be able to go along."

Today's major achievement was clearly the successful deployment of Insat 1B, the first of two weather and communications satellites to be positioned in space by the United States for the Indian government.

To have Insat 1B put in orbit from the shuttle, India paid the United States $10 million, less than one-third of what it would have had to pay if the satellite had been sent aloft on a conventional rocket. The ability to launch payloads so much less expensively is one of NASA's main selling points for the shuttle.

Most of the commercial enterprises and nations that have booked space on the shuttle for their satellites are doing so because it is the cheapest method of putting their machinery into orbit.

The shuttle is to carry an identical satellite for India in February, 1986, enabling the Indian government to serve more than 200,000 villages across the subcontinent with radio, television and telephone. In some Indian villages the people have yet to see television, hear radio or use a telephone.

"Essentially, this is a program where the objective is educating the people," Dr. S. Versantha of the Indian National Satellite Service said today at the Johnson Space Center here, from which the flight of Challenger is directed.

"I'm not saying that next month or next year everything will be televised . . . . It takes some more time, but we certainly will get there," he added.

Insat 1B was deployed from Challenger's cargo bay just after 4 a.m. today as the shuttle passed above the western Pacific Ocean near Australia.

The deployment maneuver, directed by Bluford with help from Dale A. Gardner, went flawlessly. The two deployed the satellite by punching keys on their computer console while Challenger was being flown to the proper orbital position by flight commander Richard H. Truly and pilot Daniel C. Brandenstein.

After Insat 1B was ejected and moving away from the shuttle, Truly and Brandenstein maneuvered Challenger about 15 miles from the satellite, then raised the shuttle's nose so the underside of its fuselage faced the satellite.

When that was done, a signal was radioed from India to fire the satellite's onboard engines and begin raising it on a path that is to take it next week to a point 22,335 miles above the equator. There, it is to hover over the Maldives Islands in the Indian Ocean for 10 years.

"We're delighted with the deployment. The crew did a superb job," flight director Randy Stone said.

"As far as we can tell, our orbital error at the time of deployment was no more than 5,000 feet. That equates to about two-tenths of a second of error in the timing of the orbiter's position over the Earth at the time of deployment," he said.

For the second consecutive day of their planned six-day flight, the astronauts continued communicating with Earth by using for the first time the $100 million satellite orbited during the sixth shuttle flight last April.

Although a misfiring engine aboard that Tracking and Data Relay Satellite originally placed it in an incorrect orbit, more than three months of rescue work involving almost 50 radio-controlled firings of the TDRS' tiny onboard thruster jets finally positioned it properly, near the equator just east of northern Brazil.

Each time the astronauts have used the TDRS as their communication link, it has not only improved voice and data transmission but also has given them far more time in which to communicate because their range is no longer as limited.

An identical TDRS to be orbited above the Pacific Ocean next year is intended to enable the space agency to communicate with future shuttle crews over more than 80 percent of the Earth.

Previously, NASA's ground stations allowed communication with shuttle astronauts less than 20 percent of the time they were in orbit.

"This whole experience has been a pleasant surprise to most people on the ground," Stone said. "Communcations at low-, medium- and even high-data rates have worked flawlessly today during all our tests."