What precautions are planned to prevent samples returned from Mars crashing and releasing organisms on Earth? and this answer to Why would bringing samples from Mars back to Earth be a “civilization-level changing capability”? cite the crash landing on Earth of the return capsule from the Genesis mission.

Despite the crash the mission was a success in that solar wind particles embedded in special materials were not seriously contaminated and could still be analyzed such that all success criteria were met.

That Wikipedia article links to this archived version of Space.com's Genesis Update which says in part:

Michael G. Ryschkewitsch, who heads a board investigating the mishap, said the planned test would have spotted the fatal flaw and prevented the crash.

"If the test had been done, the problem would have been caught," said Ryschkewitsch, the deputy director of NASA's Goddard Space Flight Center.

Officials at Lockheed Martin do not dispute that conducting the pre-launch test would have uncovered the error that doomed the $264 million missions.

Question: Exactly what was the nature of the test that was skipped? Was it simply a sufficiently long period of acceleration at 3 g to close the contacts or did it rise to the 30 g maximum anticipated? How was the acceleration of sufficient magnitude and duration going to be generated?

"bonus points" for information addressing why there wasn't a visual cue for the proper direction; wasn't there an arrow or something printed right on the G-switch?

Genesis crash site scenery

Wikimedia: "Genesis crash site scenery"


1 Answer 1


The planned test was a centrifuge test. They were going to take the entry vehicle up past the 10-g mark and back down. According to the JPL Mission Manager, who was my boss at the time, the g-switch was supposed to come off the peg at 3 g's, saturate at 10 g's which told the deployment controller to enable the deployment sequence start (i.e., to "arm" it), and when it got back down to 3 g's, "Let'er rip!", starting the deployment sequence that eventually would've fired the pyros to deploy the parafoil. Of course in the test the controller would've had the actual deployment sequence disabled, but we'd have seen the signals from the switch at those g levels, indicating all was working as planned. With the upside-down g-switch, we'd have gotten flatline signals from the g-switch and the problem would've been brought to light.

But the project was under budget pressure (chewing farther into reserves than anticipated) and schedule pressure: the centrifuge schedule was becoming a problem due to a backlog of tasks for the centrifuge facility. Management then said, "This accelerometer/controller system is the same as the one on the Stardust spacecraft, and that system passed its centrifuge test. We're declaring heritage for that system so we'll skip the test."

They didn't tell us that, though all the components of the system were identical, to fit into the Genesis spacecraft they all had to be mounted on a board of different shape so the mounting configuration was different! Had we at JPL known that, the heritage claim would've gone out the window.

I can't verify it, but months after the crash the Genesis Project Mission Assurance lead (the late Robert Axsom) told me that indeed the g-switch was labeled for proper orientation — but the way the blueprints showed it, it was upside-down!

And yes, they are recovering much of the science originally proposed, but the cleaning procedures and analysis procedures are more laborious and expensive.

When the crash occurred, on camera for everyone in the JPL mission control room in Building 230 to see, I was sitting next to the Director of JPL, Charles Elachi, and the NASA Deputy Associate Administrator for Planetary Science. I'm really glad that when the crash occurred they didn't both glare at me!

  • 11
    $\begingroup$ They were probably already too busy imagining themselves being glared at by some congressional sub-committee, review board, or whatnot. Thank you for the thorough answer! $\endgroup$
    – uhoh
    Commented Dec 16, 2020 at 8:23
  • 17
    $\begingroup$ I imagine that the management who ordered the test to be skipped got promoted, as per standard US government culture. $\endgroup$
    – Ian Kemp
    Commented Dec 16, 2020 at 12:53
  • 28
    $\begingroup$ These first-person experiences and recollections from people who were actually involved with the events surrounding these Space Exploration questions is why I love StackExchange! $\endgroup$
    – Milwrdfan
    Commented Dec 16, 2020 at 15:27
  • 11
    $\begingroup$ @OrganicMarble Actually, it was the contractor — in the Discovery Program lingo, called a "partner" — who proposed eliminating the test. But the managing partner, JPL, had to approve of it. Not aware that the controller hardware had been reconfigured, that approval was given. $\endgroup$ Commented Dec 16, 2020 at 16:31
  • 10
    $\begingroup$ @ErikE It wasn't a matter of a "module" (actually a mounting board) being inserted upside down; the board was correctly installed. The g-switch, a relatively small, non-descript (from the outside) component with some wires coming out of it, was mounted on the board and connected the way the blueprints showed it being mounted and connected — but the orientation of that component shown on the blueprint was upside down on the board! Whomever initially drew that blueprint diagram goofed — and how! And ... whomever checked that blueprint and OK'd it (if that actually happened) goofed — and how! $\endgroup$ Commented Dec 17, 2020 at 4:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.