The Longest Lifeline Ever

24th July - 25th September, 1998.


Phew! Found! In one piece, but.....



could we regain control?





SOHO was found to be slowly rotating near its expected position in space. But we had no way of whether it was still usable or even contactable.




So we knew where SOHO was and what is was doing - which was nothing except slowly rotating to face the Sun. Gradually, SOHO's batteries were gaining more and more power, giving us a better and better chance of getting a message from SOHO.....

...eventually, after 37 attempts, contact was re-established with SOHO on 22:51 GMT 3rd August 1998, following six weeks of silence.






One million miles of lifeline

Now that we had contacted the spacecraft, scientists worked round the clock to get SOHO back under proper Earth control. Why the rush? Well the spacecraft was still rotating its solar panels towards the Sun. Because there is no friction in space (do you know what friction is? can you think of any earth situations where friction is important?) then the solar panels would eventually rotate away from the Sun. The batteries would run out again and we would lose SOHO .... maybe this time forever.



There were a lot of problems to think about with SOHO being so long out of Earth control....
  • the batteries had to be charged - no power, no SOHO!
  • the thruster fuel had to be thawed out to move the spacecraft into its correct orbit.
  • the bugs in the computer programs.
  • SOHO had to find the Sun again!



12 August 1998 - batteries charged.
28 August 1998 - fuel thawed out.
14th September 1998 - computer programs fixed and tested.
16th September 1998 - SOHO finds the Sun again.



SOHO spacecraft fully operational again!