NASA's Europa Clipper Launch

Oh cool, someone that actually worked on it!

I was just thinking about how much pressure there must be on everyone involved in Discovery Class missions. People's entire professional careers, billions of dollars, so much at stake!

Is the pressure something significant, or is it spread across so many people that there is little trouble sleeping at night?

The one that gets to me is the Huygens part of the Cassini-Huygens mission. Cassini was launched October 15th, 1997, Huygens separated from the Cassini carrier on December 25th 2004, and landed on Titan on January 14th, 2005. So it was in space for over 7 years before it got it's 90 minutes of time on the surface. That was actually towards the upper-end of expected lifetime on Titan- somewhere between 30-90 minutes was the expected lifetime of the lander(1). So you build and test and test and test (2) for years before launch, then the probe travels for seven years in outer space, and then it gives you an hour and a half of data and that's it. Your entire life for ... 15 years? Resolved in 90 minutes. On the shorter end of probe lifespan, it would have died before the first signal even reached Earth!

1: Officially I believe the expectation was "3 minutes" but that was a deliberate under-promise so that a success could be declared as long as they got any message at all from the lander on the surface: I have second-hand accounts that 30 minutes was what the scientists considered the minimum.

2: Even with all that testing, disaster almost struck. It wasn't until after the launch that someone realized even all of this testing had missed something important. The radio communications between Cassini and Huygens would be affected by the Doppler shift of Huygens hitting Titan's atmosphere, which would be unpredictable changes to velocity. After launch they had to rejigger when Huygens would be launched to a time when the signals would be perpendicular to the direction of travel so the shift wouldn't affect the radio waves so much that the Cassini receiver firmware (which could not be modified after launch) could still detect the signals. And also with all of that testing, ESA's instructions to the Cassini probe missed turning on one channel on the receiver and so half of the pictures that Huygens transmitted had nothing listening in and were lost.

Thanks for that. It made me wonder: who was it? Were they in the shower, did they awake from a nightmare?

Here is an HN post from 2014, "How a Swedish engineer saved a once-in-a-lifetime mission to Titan (2004)" [0]

Since the link has rotted away, here is the archive link to the IEEE story. [1]

[0] https://news.ycombinator.com/item?id=7472495

[1] https://archive.is/3oj6P (archive.org is still not working reliably)

> Your entire life for ... 15 years? Resolved in 90 minutes

I ultimately decided against pursuing a career in aerospace engineering after talking to engineers who worked a similar time frame on a project only to watch it get killed in 30 seconds' debate in Congress.

>Is the pressure something significant, or is it spread across so many people that there is little trouble sleeping at night?

When you are on contract for something, you deliver to the contract, and are done when you successfully meet the customer's requirements. So in that sense you don't have the same exposure to the program risks.

However, I've been part of one-off science missions before, and there is a different feeling beyond the contract obligations, though it's certainly abstracted through the many layers of sub-, sub-contracts.