A more than 15-year old laptop doesn't go for much on eBay -- unless it's the one Bill Clinton used to send the first ever US presidential email.

The still-functional laptop -- with Clinton's cheerful exchange with Space Shuttle astronaut John Glenn in November 1998 still on the hard drive -- is the featured item in an online sale by Massachusetts-based RR Auction.

"I wouldn't be surprised if it goes for $100,000 or more. Just the content of it is awesome," Bobby Livingston, a spokesman for the auction house that specializes in rare and unusual collectibles, told AFP on Monday.

Glenn, a US senator who in 1962 had been the first US astronaut to orbit Earth, was on a nine-day mission aboard the space shuttle Discovery when he told NASA he wanted to email Clinton, who was in Arkansas visiting friends.

"This is certainly a first for me, writing to a president from space, and it may be a first for you in receiving an email direct from an orbiting spacecraft," wrote Glenn, then 77.

Clinton was keen to receive the message, but when his staff couldn't readily find him a computer to do so, White House physician Robert Darling stepped forward with his trusty Toshiba and his personal AOL email address.

"Hillary and I had a great time at the launch," wrote Clinton, referring to Discovery's liftoff from the Kennedy Space Center a few days earlier, in his reply. "We are very proud of you and the entire crew, and a little jealous."

- Kept emails intact -

In an interview with a US journalist in early 2000, Clinton said he never used email due to security concerns, but acknowledged emailing Glenn in space as well as some US marines and sailors at sea at Christmas.

Prior to selling the laptop in 2000, Darling took care to keep the historic email exchange on its hard drive, and made a copy on its internal floppy drive, while deleting all other data.

RR Auction is selling the laptop, consigned by a private collector, with a small trove of documentation that includes a typed memo from Darling to NASA explaining the back story -- plus instructions on calling up the emails.

Clinton, wrote the doctor, "seemed to really enjoy himself particularly when he pressed the 'send' key and realized that at that instant his message was travelling through cyberspace and into real space."

"It's a remarkably historic item," said Livingston in a telephone interview, adding that the laptop should appeal to avid collectors of presidential, space and computer memorabilia.

The Toshiba Satellite Pro 435CDS typically ran Windows 95, with up to 16 megabytes of non-removable system memory and a hard drive ranging in capacity from 2.1 to 10 gigabytes.

By comparison, a low-end iPhone 5C today has a 16 gigabyte flash drive.

Other space-related items in the auction, which runs until April 16 at www.rrauction.com, includes a Beaulieu 16mm movie camera that spent three years on a Soviet space station.