Virgin Galactic Grounded by EMI - Page 1
Forum section: electronics / general

author: JustMeHere
author_rank: Frequent Contributor
timestamp: March 01, 2021, 05:04:04 am
content: "the Dec. 12 aborted suborbital test flight of the vehicle, which was caused by electromagnetic interference (EMI), according to SpaceNews. Virgin Galactic officials said that EMI caused a flight computer to reboot at the same time that SpaceShipTwo's engine ignited."Anyone care to speculate what type of EMI would do this? Suborbital flight will become an important part of our future.https://www.space.com/virgin-galactic-spaceshiptwo-delays-space-tourism-flights-2022

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 01, 2021, 01:34:15 pm
content: Branson! Get me some ferrites!

author: daqq
author_rank: Super Contributor
timestamp: March 01, 2021, 01:57:59 pm
content: That'll be a fun issue to recreate in the lab.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 01, 2021, 02:56:36 pm
content: I'm guessing they failed IEC 61000-4-8.

author: Gyro
author_rank: Super Contributor
timestamp: March 01, 2021, 07:43:38 pm
content: "Will all passengers please turn off their mobile phones, laptops and other electronic devices before launch".

author: jmelson
author_rank: Super Contributor
timestamp: March 01, 2021, 07:54:16 pm
content: Quote from: JustMeHere on March 01, 2021, 05:04:04 amI worked at NASA Wallops Island in 1971-1972. They used a bunch of radars to track the rockets during launch. Some of this was to determine early orbital parameters, some of it was for range safety., and some was so that data acqusition dishes could slave to the radar. So, at least a few radars were pointed and locked onto the rocket as it sat on the pad. They were used to EMI from the radars, and if the guidance or payload computers acted up, they would ask the radars to point above the rocket and try to intercept it right after launch. Sometimes they missed their aim, and then had a frantic time trying to get the radar to lock on a moving target.Jon

author: Cerebus
author_rank: Super Contributor
timestamp: March 01, 2021, 08:16:23 pm
content: Quote from: daqq on March 01, 2021, 01:57:59 pm"Why the &%^^&* is the wall of the anechoic chamber lying scattered all over the car park!?!""Well, funny story..."

author: SeanB
author_rank: Super Contributor
timestamp: March 02, 2021, 04:56:39 am
content: Well I would guess that rubbing a lot of moving conductive gas against an insulating surface can generate quite a static charge, and this charge can be pretty big, and will cause a lot of issues as it seeks to equalise. Hot gas, and the fuel as a solid, very likely a poor electrical conductor, so there will be an enormous charge building up there in that engine. Likely they either will have to add some carbon shapes in there to allow charge to bleed away, mounted near the nozzle, or will have to make some changes to the fuel grain to make it more conductive.

author: harerod
author_rank: Frequent Contributor
timestamp: March 02, 2021, 09:21:24 pm
content: EMI being one of my too many passtimes, I read the thread yesterday, but stopped myself from writing a comment. Well, here we go:I would be most interested in the actual timing of the incident. Is there any further, reliable information available? Especially when did the incident occur? Say, at pre-start, when some pumps spun up, in the moment of ignition, or during the actual burn? And yes, I read the original post.Hi jmelson, your story reminds me of Neil Armstrong nearly buying a farm while flying a bedstead. He also gave radar as an explanation.Take the guidance radar of the HAWK missile system. Many friendly pilots urgently asked to switch that bloody thing off, because their avionics went haywire (old story, ca. 1990, German Hairforce). I mean, what were we supposed to do? We were allowed to fire one missile every year, from some Greek island into the Mediterranean Sea, somehow we had to pass the time...