Helium Hard Disk Drives at Altitude
Following on from recent system problems, scientists involved in the Event Horizon Telescope project have announced that they will be using helium-filled hard drives from Western Digital’s HGST division to store their deep space observation data. The research project combines radio telescope data from 10 different high altitude mountain geographic locations into a single functional observatory. These locations have however presented fairly unique data storage problems.
When the Large Millimeter Telescope began recording data on an array of 32 traditional hard drives, 28 of them failed due to the read write heads crashing on the surface of the disk platters. In standard technology a hard disk drives’ read write heads are designed to float on a cushion of air, but when the air density begins to drop due to the thinning atmosphere at altitude, the pressure within the drive isn’t sufficient to maintain this air bearing. The scientists involved consulted HGST who advised that sealed helium hard disk drives would constitute a viable solution to their requirements .
The amount of data the telescopes collect precludes the use of SSD’s. Each participating telescope collects over 900 T Bytes of project data. Whilst the price of consumer SSD’s has dropped precipitously in recent years, enterprise SSD’s are still quite relatively expensive.
Once the data has been gathered at each individual location, the entire set of drives is physically shipped to the MIT Haystack Observatory, where a network of over 800 processors crunches the data through what is referred to as a “silicon lens.”
By using advanced algorithms and specialized processing techniques, scientists are able to analyze the event horizon of the super-massive black hole at the heart of our own galaxy — Sagittarius A*.