We were discussing this in the chat room yesterday, and I thought it might make an interesting question. While missions are lasting longer today than they perhaps ever have, it seems like there are relatively few launches compared to the recent past. We could only come up with one mission in the window of SpaceFlightNow that is planned, March 4th InSight. I'm sure there are others, but it seems strange that NASA only has one interplanetary mission for the next many months.

The question is, is the rate of launch of missions over a short (Let's say 2 years) lower than the standard rate of launch of missions over, say, the last 10 years, and if so, why?

  • $\begingroup$ Solar Probe Plus and Osiris-Rex are to be launched in 2018 and 2016, so the Sun and asteroids are next up. With Messenger and Magellan, all planets out to Saturn have been orbited. The Solar System has been reconnoitred. I think that the exploration shifts into in depth follow up missions, like Juno and the Mars campaign. I'm afraid that could be less spectacular and politically attractive. A congressman supports a Europa mission because of spectacular ideas about alien life. A seismometer on Venus is not as sexy, and unfortunately that matters. $\endgroup$
    – LocalFluff
    Jan 5, 2016 at 9:57
  • $\begingroup$ Maybe the increasing number of interplanetary missions of ESA, JAXA and China has lead to NASA giving lower priority to planetary science, mostly specializing on Mars? Most missions seem to be the result of international cooperation to some degree. Looking at NASA in isolation is maybe not representative for the science community which is very international. $\endgroup$
    – LocalFluff
    Jan 5, 2016 at 10:01

2 Answers 2


Yes. And even worse, there are no planetary launches planned in 2017, 2018, or 2019! Zero. Zippo. Nada. As you can see from the Planetary Society plot, this is due to not having such missions in planning in several preceding years. Here is the source of the graphic with some more information.

planetary launches 2004 - 2020

  • $\begingroup$ This answers the "is it happening" question, but doesn't answer the why. The budget seems to be a bit less, but not excessively so. It is true that missions take a while to prepare, which might be one of the factors as well (Funding drops in 2013 due to budget issues), but still, this like there is more to the story... $\endgroup$
    – PearsonArtPhoto
    Aug 26, 2015 at 16:06
  • $\begingroup$ The launch count doesn't look too bad - the future years have 4 launches in 5 years, the past years have 12 in 12 so little change... $\endgroup$
    – Andy
    Aug 26, 2015 at 16:19
  • 3
    $\begingroup$ The issue is really the pipeline. There is a precipitous drop in missions in development, which reduces the number of conceivable future launches. However for the launches you can group it lots of ways. I would average over three-year periods, giving 4, 3, 3, 2, 2, 2 launches in each three year periods (2004-2006, 2007-2009, etc.). $\endgroup$
    – Mark Adler
    Aug 26, 2015 at 16:39
  • $\begingroup$ Yes, I recall discussion (from Planetary Society) that the recent years' missions are the tail end of funding and development already in the pipeline, with new funding absent, but several years lag before we notice it because of the lag. $\endgroup$
    – JDługosz
    Aug 26, 2015 at 17:35
  • 1
    $\begingroup$ @PearsonArtPhoto The budget has been/is projected to be roughly constant through the period 2007-2020 but inflation means that amount of money buys less. In real terms, the budget seems to be decreasing, though not by a huge amount. $\endgroup$ Aug 26, 2015 at 18:33

The anomaly may not be that the number of missions is declining, but that it's been so high in the past few years.
Here are some new graphs from Emily Lakdawalla at the Planetary Society. First the missions for the 2003-2018 timeframe. Dark blue = NASA, I haven't looked at cooperative missions.

Missions by agency, 2003-2018

(large version)

And the missions for the 15 years before that:

Missions 1987-2002

(large version)

In 2015, I count 11 active NASA missions, in 2018 that declines to 7. That includes Opportunity, which was unexpectedly long-lived. But in 2005, there were 8 active missions.

We can also see the highest number of missions at any point in the 1987-2002 timeframe was 8 (in 1999), with most years at 6 missions or less.


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