I.m not sure about the log graph....but I might go about it this way:
We can create a semi-log graph with the years being on the x axis (linear) and the distances (as base 10 logs) are on the y axis
Let 1972 be year 0
Let 2003 be year 20
Let 2009 be year 26
The distance from the Sun to the Earth (the launch site of Pioneer 10) in 1972 is 140,000,000,000 m
Expressing this as 10 raised to a power wehave that log 140,000,000,000 = 11.14
So ....the first point on the graph would be (0, 11.14)
In 2003, Pioneer 10 was 11,933,236,224,000 m from the Sun
So..... log 11,933,236,224,000 ≈ 13.08
So....the point (20, 13.08) would be on this graph
In 2009 Pioneer 10 was 14.229.146,880,000 m from the Sun
So....log 14,229146,880,000 ≈ 13.15
So....the point (26, 13.15) would be on this graph
One last thng..... the distance from the Sun to Aldebaran = 614,947,480,717,752,000 m
So....Log 614,947,480,717,752,000 = 17.78
This will not have a point associated with it.....so.....I'll leave it to your discretion as how you want to show this
You would need to label the x axis as "Years Since 1972"
Label the y axis as " Base 10 Log Distances "
Here's the graph (you would need to draw a curve through these points.....I don't know how to do that in Desmos)
https://www.desmos.com/calculator/rsuu7k8yj6
That's about the best I can do with this !!!
