Antenna Problems on SOHO

Image credit: ESA

The NASA/ESA SOHO spacecraft, which observes the Sun, is having problems pointing its high-gain antenna, which it uses to transmit data back to Earth. The cause of the problem hasn’t been figured out yet, but experts think there’s something wrong with its motor or in the gear assembly that steers the antenna – fortunately, its low-gain antenna is still working, so they can still communicate with the spacecraft. If they can’t figure out the problem, SOHO isn’t going to be able to transmit data back as quickly, so there will be blackout periods.

The ESA/NASA SOHO spacecraft, launched in 1995, has been delivering outstanding data about the Sun for over eight years. Recently, however, an anomaly on the pointing mechanism of its high-gain antenna has been recorded.

The high-gain antenna is required to transmit the large amounts of data from SOHO’s scientific observations to Earth. From SOHO’s orbit, the antenna has to be pointed in the proper direction – like a flashlight – for the data to be received at Earth.

The exact nature of the antenna problem is not yet known, but the experts think that a malfunction has occurred in its motor or in the gear assembly that steers the antenna.

SOHO is safe, as the spacecraft has a low-gain antenna, used to control the spacecraft and monitor both spacecraft and instrument health and safety, which remains operational. However, if the high-gain antenna problem persists, there will be periodic losses in the real-time transmission of scientific data of about two and a half weeks each three months. The first blackout is estimated to begin sometime late in the week of 22 June 2003.

A number of options are currently being investigated by the SOHO team to fully recover or minimise any real-time scientific data loss. A joint ESA/NASA press release will follow shortly.

Original Source: ESA News Release