How It Worked

The TubeRat 1 probe was not given advance publicity because the mission carried significant risks.

The probe was launched as a secondary payload aboard a Boeing Delta II rocket from Cape Canaveral, Florida on January 12, 2005.

TubeRat 1 was inspired by the Hughes HGS-1 satellite. (See archived press release at Boeing and an article at SpaceToday.) The satellite was salvaged from an unintended highly-inclined orbit in Spring 1998. It was sent around the moon and back to Earth into geosynchronous orbit. HGS-1 was the first commercial satellite to fly by the moon. It proved a regular satellite can get there.

TubeRat 1 was built around a surplus 490 Newton rocket engine obtained in Southern California. These engines are commonly used as a "kick motor" to get satellites in their planned orbit.

The thrust of this engine limited the probe to a weight of 120kg at the beginning of the lunar descent burn. The rest of the design fell out of these requirements.

Like HGS-1 did in 1998, TubeRat 1 increased the altitude of its orbit by making "puffs" of its rocket motor at the low point (perigee) of each orbit. Each time the high-end of the orbit was raised. Eventually, TubeRat 1 got far enough away from Earth's gravity that it was captured by the Moon's gravity.

The journey took 78 days.

The descent went according to plan. Alert viewers of the Mission Control video may have noticed that not everything went smoothly during the landing. Three airbags failed, making the landing rougher than expected. The airbag failures and a suspected leak in a motor pressurant line sent TubeRat 1 tumbling for 1.7 kilometers in the Moon's lighter gravity. It had descended onto its intended coordinates before rolling away.

The coordinates of the landing site will be made available to teams which register to attempt the LunaCaching Prize.