SOHO is well past the design life and has suffered several systems failures. Through good work by the ground controllers, they've managed to keep the system online. However, sooner or later, SOHO is going to die like all other spacecraft.

SOHO has provided wonderful scientific data on the sun. It has also proven very valuable as a monitoring station for solar activity. I hope someone is already working on the follow-on vehicle, at least for the monitoring capability. That's very important data on the space environment. Some other satellites, like GOES, monitor part of the solar effects but we need the early warning that a system like SOHO provides.

We need a replacement, and it takes years to develop something like that. One possibility might be to mount some of the SOHO instruments on the boondoggle GoreSat (Triana) satellite. Monitoring the sun is far more important than taking pretty pictures of the Earth. At least this way, the money wasted on GoreSat might not be a total writeoff.