Artist's rendition of the SOHO satellite

GREENBELT, Maryland. (CNN) -- NASA has re-established contact with the disabled SOHO solar satellite, a billion dollar spacecraft parked between the Earth and the sun.

NASA has tried almost constantly to communicate with SOHO since contact with the satellite ended abruptly on June 24. Astronomers located the satellite in late July using radio telescopes based in Puerto Rico, but were unable to communicate with it.

Contact was re-established at 6:15 p.m. EDT Monday when SOHO "replied" to signals radioed to it from NASA's Deep Space Network station at Canberra, Australia.

Communications with the satellite have been intermittent, officials said, and no data has been received. Mission scientists do not know if SOHO has been damaged or if it will be possible to regain control of it. The space agency also does not know yet if SOHO will be capable of solar observations in the future.

But mission scientists consider it an encouraging sign that SOHO can receive and respond to ground commands.

SOHO (Solar and Heliospheric Observatory) is a joint project of NASA and the European Space Agency.

A preliminary report by NASA in July said software glitches in the command and control computer caused SOHO to spin out of control. Mission controllers believe that, as the satellite moved out of proper alignment with the sun, its solar panels could no longer supply electricity to the communications equipment and its antennas were no longer angled toward Earth.

NASA believes the spinning spacecraft eventually rotated back into alignment with the sun, and the solar panels were able to recharge the onboard batteries.

SOHO was launched in 1995 to study the sun from an area out in space known as the L-1 position, which is 1 million miles (1.6 million km) from Earth, between the Earth and sun.

It completed its initial two-year science mission early in 1998, but solar scientists had hoped it would continue to operate for several more years.