What makes time on the DSN so expensive?

Question

David Hammen wrote in a comment on Why there is not a single orbiter for Uranus or Neptune? that:

The two Voyager satellites still receive multiple Deep Space Network contacts per week, each of which costs several thousands of dollars to tens of thousands of dollars. Then there are people. The most recent Voyager Space Flight Operations Schedule lists eleven JPL employees. I'd be shocked if a fully-loaded FTE JPL engineer costs less than $250K/yr. Plus there are researchers in other NASA centers and in universities who are supported by the Voyager budget.

Let's go with $10,000 per contact for the Voyagers, via the Deep Space Network, to have a figure in the middle of that range. (If someone has a better estimate, by all means feel free to use that for an answer.) At the low bit rates involved, a contact might last for a few hours. I realize that the equipment is awfully expensive and probably takes a small army of people to maintain, but that still boils down to a few thousand dollars per hour of radio time -- pretty close to a dollar per second. Note that this is in addition to the people actually working to directly support the Voyager missions.

What makes using the DSN so expensive?

A rough costs breakdown would likely make a perfect answer to this question, but a general reasoning could pass as well if it is well-reasoned enough.

Answer 1

I realize that the equipment is awfully expensive and probably takes a small army of people to maintain, but that still boils down to a few thousand dollars per hour of radio time ...

The cost in 2017 dollars ranges from \$954 per hour of contact for use of a 34 meter High-Speed Beam waveguide antenna to \$4770 per hour of contact for use of a 70 meter antenna, plus charges for an additional hour for setup and shutdown costs. The specific formulae for standard support (see NASA's Mission Operations and Communications Services for details) is

$$\begin{aligned} A_f &= R_b\, A_w\,(0.9 + F_c/10) \\ C &= A_f\, (1 + T) \end{aligned}$$ where

• $A_F$ is the hourly aperture fee;
• $R_b$ is the basic hourly fee, \$1057 (2010 dollars);
• $A_w$ is the aperture weighting:
  • 0.8 for a 34 meter High-Speed Beam waveguide antenna,
  • 1.0 for some other 34 meter antenna,
  • 2.0 for two 34 meter antennae,
  • 3.0 for three 34 meter antennae,
  • 4.0 for four 34 meter antennae, and
  • 4.0 for a 70 meter antennae;
• $F_c$ is the number of contacts per week;
• $C$ is the cost per contact; and
• $T$ is the contact duration in hours.

For example, four two hour long contacts per week with a 70 meter antenna over the course of a year costs \$3.43 million in 2010 dollars, or \$3.87 million in 2017 dollars. Changing those four two hour long contacts per week to one eight hour long contact per week reduces the costs to \$1.98 million in 2010 dollars, or \$2.23 million in 2017 dollars. More frequent short duration contacts are penalized twice, once with the factor $0.9+F_c/10$, and once again with the additional hour (45 minute setup and 15 minute shutdown) per contact.

Why so high? This is very expensive and highly customized equipment. There aren't very many 70 meter antenna in the world. NASA has switched to full cost accounting, which means that projects that use the DSN have to pay for their share of the use of this very expensive equipment. This sharing includes maintenance and upgrade costs.