Solar Maximum Mission (SMM) scientists plan to participate in a worldwide campaign to observe the Sun in September 1988. It is hoped that solar physicists from the Soviet Union and several European countries with experiments on the Soviet spacecraft PHOBOS (a mission to Mars which will carry solar instruments) will also be involved. PHOBOS will be launched in July; the TEREK instruments (a soft X ray imager, and ultrasoft X ray imager and a white light coronograph) will image the Sun twice every 5 days. Other instruments will obtain nonimaging solar data much more frequently. Now that the rapid rise phase of the new solar cycle is well under way, such joint observations of the Sun should be particularly fruitful.