After NASA’s creation in 1958, the agency was tasked with coordinating America’s activities in space. At first this included a huge push to land humans on the Moon by the end of the 1960s. Since that time, the agency has sent dozens of probes to explore the inner and outer planets as well as small bodies including Pluto. These visualizations show the shifting priorities of the space agency, the overall spending and exploration thrusts and the long-term commitment by the US government to explore.
 
The Dataset: Planetary Exploration Dataset
  • a public dataset prepared by the Planetary Society.
  • Integrates the spending history, by year, of every NASA planetary science mission and related activities. The annualized dataset enables improved adjustments for inflation and allows direct comparisons between past and current planetary exploration efforts within the United States.
  • enables analysis of shifting national priorities in space exploration, spending by destination, roles of major programs, research, launch costs and more.

Missions by Destination

Chart Type: Interactive Tree
Use the visualization to explore the solar system the the dozens of probes sent to explore the solar system. The story opens on the Moon with with Ranger, Surveyor and Prospector. These orbiters and landers helped pave the way for the Apollo program to land humans on the Moon by the end of the 1960s. The exploration of the solar system breaks down according to the destinations outlined in the Planetary Budget Dataset. This visualization, built in D3.js, is interactive with the planetary nodes opening a list of missions to those destinations. Outer planets include Jupiter, Saturn, Uranus and Neptune. Small Bodies include Pluto, asteroids and comets. The visualization shows the depth of missions carried out since the beginning of the Space Age. This does not include missions to research our own planet Earth nor does it show missions by other countries. The bulk of the missions appear to be centered around Mars but the Lunar Ranger, Surveyor, and Prospector programs included multiple missions all aimed at characterizing the Moon before astronauts arrived in 1969.
 
 
Mars exploration historically is tied to exploration of past life on the fourth planet. Mars’ dry and cold, cratered terrain shows abundant evidence for the presence of liquid water in the planet’s remote past. Mars appears to be a next destination for human expeditions and it does bear out as the main recipient of funding from NASA and Congress.
 
This visualization would have drastically improved had I been able to include a set of icons specifically created to replace the circle SVG elements for the destinations.

Mercury


Venus


Earth and Moon

Mars

Jupiter


Saturn


Uranus

Pluto
      
 

Funding by Planetary Destination 1960-Present

Chart Type: Bubble Chart
Since Mars appears to be the runaway historic favorite of planetary exploration funding, let’s take a look at how each of the destinations compare. The chart Funding by Planetary Destination 1960 – Present shows Mars and the Outer Planets soaking up much of the funding from NASA while the explorations of Mercury and Venus show much less funding. The dataset is a high-level and simple view of the dataset aggregating all funding by destination. Originally this visualization was to be the jumping off point for diving deeper into the specific missions using view coordination but the code to create the bubble chart in D3 never really worked. This visualization is the heart of the question I wished to explore in the dataset; what destinations and programs does NASA focus.
 

Mars dominates historic funding for planetary exploration by the United States from 1960 to present. The total budgets for these planets are shown in millions of dollars (USD). (Data source: Planetary Society Planetary Science Budget Dataset – https://www.planetary.org/space-policy/planetary-exploration-budget-dataset)

 
Mars is clearly an important destination. As mentioned above, Mars is a possible source for ancient life in the solar system and answering this question appears to be foremost in NASA’s explorations. By diving deeper into the dataset, several complex missions to Mars, such as Perseverance and Curiosity, have cost billions of dollars due to the engineering of rovers as well as their long lifespan. As an aside, NASA builds spacecraft and landers to withstand extreme radiation and temperatures found in space and on the planets and moons of the solar system. Much press is given to the tenacity of the Spirit and Opportunity rovers, the Voyager spacecraft and the multi-mission extensions of the Galileo and Cassini orbiters. These missions lasted far beyond their anticipated lifespans.
 
 

Funding by Destination over Time

Chart Type: Scatterplots/Line Graph
NASA’s relative expenditures during “the golden age” of planetary exploration from 1960-1980 show a huge effort to explore the Moon prior to the first human landing in 1969 as well as a push to understand Mars with a leadup to the landing of Viking 1 and 2 in 1976 and 1977. The budgets for Mars in the early 1970s rivals the exploration budget for the Moon showing that Mars was always an important exploration target. The chart below, built in D3.js, also reflects NASA’s shifting decadal goals clearly. In the 1980s and 1990s, funding for research of the outer planets expanded due to the successes and incredible discoveries made by the Voyager spacecraft. Currently, budgets to explore the outer planets dominate with the Juno mission to Jupiter and the upcoming Europa Clipper mission to Jupiter’s icy moon. Increased Mars funding is also visible in this chart. Also notable is a bump in the blue line between 2015 and 2020 related to Small Bodies. New Horizons mission to Pluto and beyond is included in this exploration group and there is a current push to not only land probes on comets and asteroids but also to return samples so scientists can study materials nearly unchanged from the origin of the solar system 4.5 billion years ago.
Caption: Chart displays NASA’s budget for planetary exploration by destination. The exploration budget chart reflects NASA’s exploration goals based on their decadal surveys and highlights the agency’s shifting priority from the Moon prior to 1970, Mars throughout the 70s and to the outer planets in the 1980s and 90s. (Data source: Planetary Society Planetary Science Budget Dataset – https://www.planetary.org/space-policy/planetary-exploration-budget-dataset)
 
Extra Visualization: Planetary Science Budget 1960-2025
A related scatterplot below, built in D3.js, extends the understanding of the “Funding by Destination Over Time” by showing the increased planetary exploration budgets (actual and requested) since 1960. The increase clearly shows either the US commitment to explore the planets or a desire to maintain US leadership in planetary and lunar exploration. So important is this goal that it’s interesting to note the closeness of actual budget versus requested budget. It would be interesting to compare to other government agencies over this time period. The zero values from 1998 – 2002 requested budget are not explained in the dataset.
Caption: Planetary Science budget from 1960 to 2025. Red denotes NASA’s actual budget for planetary exploration while blue shows the actual expenditure. (Data source: Planetary Society Planetary Science Budget Dataset – https://www.planetary.org/space-policy/planetary-exploration-budget-dataset)