He made a variety of appearances during 2008 in connection with the 40th anniversary of the series.

Episode celebrated the 20th anniversary of the series.

An updated version of the documentary was commissioned for the 30th anniversary of the series.

It was released on April 2, 2008 as part of the 40th anniversary of the series.

The book was released to commemorate the 35th anniversary of the series, and features several references to the series' past.

Releases then stalled until 2010, when season 4 was released, in part to commemorate the 50th anniversary of the series.

Summer 2007 marked the 30th anniversary of the series.

The episode was designed to coincide with the 30th anniversary of the original series.

Another commemorative stamp was published on the 90th anniversary of the series in 2009.

Mission: Save Earth), marking the 50th anniversary of the series.