13 May 2008
Cell Phones More Expensive Than Hubble Space Comms
by Kate Melville
A British space scientist has worked out that sending texts (SMS) via cell phone works out to be far more expensive than downloading data from the Hubble Space Telescope. Dr Nigel Bannister, from the University of Leicester, made the calculations for the UK television program The Mobile Phone Rip-Off.
To arrive at his finding, Bannister calculated the cost of obtaining a megabyte of data from Hubble - and compared that with the UK0.05p (US$0.10) cost of sending a text. "The bottom line is texting is at least 4 times more expensive than transmitting data from Hubble, and is likely to be substantially more than that," he noted.
"The maximum size for a text message is 160 characters, which takes 140 bytes because there are only 7 bits per character in the text messaging system, and we assume the average price for a text message is UK0.05p (US$0.10). There are 1,048,576 bytes in a megabyte, so that's 1 million/140 = 7490 text messages to transmit one megabyte. At UK0.05p each, that's UK374.49 (US$750.00) per MB - or about 4.4 times more expensive than the 'most pessimistic' estimate for Hubble Space Telescope transmission costs," Bannister explained.
Bannister said it had been difficult to work out exactly how much Hubble data transmission costs. So he contacted NASA who gave him a firm figure of UK8.85 (US$17.50) per megabyte (MB) for the transmission of data from HST to the Earth.
But Bannister admits that some of his calculations involved a little bit of guesswork. "This [figure] doesn't include the cost of the ground stations and the time of the personnel along the way, but it is an unambiguous number for that part of the process. So that's UK8.85 (US$17.50) to get each megabyte from Hubble, to the first point of contact on the ground, but no further. Hence we need to go a little bit further to estimate exactly how much it costs to transmit data from Hubble to the end user - i.e. to the data archive which scientists can access. This is difficult, so I had to make some conservative assumptions."
To that end, Bannister estimated the cost of the data from Hubble could vary between UK8.85 (US$17.50) and UK85 (US$170.00) per megabyte - much cheaper than the UK374.49 (US$750.00) per megabyte cost of transmitting one megabyte of text. "Hubble is by no means a cheap mission - but the mobile phone text costs were pretty astronomical," he guffawed.
Source: University of Leicester