When do we beat this?

The altitude record for unmanned balloons was (1991 edition of Guinness Book) 51.8 km (170,000 ft). The vehicle was a Winzen-Balloon with a volume of 1.35 million cubic metres, which was launched in October 1972 in Chico, California, USA.[citation needed]

In 2002 Japan achieved a new record: an ultra-thin-film balloon named BU60-1 made of polyethylene film 3.4 µm thick with a volume of 60,000 m³ was launched from Sanriku Balloon Center at 6:35 on May 23, 2002. The balloon kept ascending slowly at a speed of 260 m per minute and successfully reached the altitude of 53.0 km (174,000 ft), establishing a new world record for the first time in 30 years.