Sundial of the month September

It was already planned for 2001 to bring a sundial to Mars, and it should have arrived there in January 2002. That launch was postponed.
However, June and July 2003 saw success: two sundials were launched, and will land in January 2004.
That is when the real gnomonic game starts.

Initially it was the intention that the sundial would be by itself in the landing area, a stationary instrument like most sundials.
However, the two now underway are placed on the Mars vehicles, and as such have become mobile sundials.

The vehicles carry a camera that determines the position of the sun, and so the orientation of the sundial is known.
On earth the appropriate sundial pattern is calculated and overlaid on the image of the sundial.
We can see the time and date the sundial indicates via Internet.
However, these will be according to a Martian time system: the Mars date and the Mars hour.

Some data of these small sundials:

• Mass: 62 grams
• Dimensions: 8.0 x 8.0 square cm, 0.6 cm thick; gnomon height 3.5 cm; sphere diameter 2.0 cm.
• Motto: "Two Worlds, One Sun"

Some links:

Everything concerning the Mars missions
More figures of the sundial

Source: Woody Sullivan, USA, member of the design team.

Fer de Vries