It’s the last Rocket History of the season, and we’re ending on a good note with Japan’s GEOTAIL mission. This satellite was a collaboration between the Institute of Space and Astronautical Science of Japan (ISAS) – the predecessor of the Japan Aerospace Exploration Agency (JAXA) – and NASA. Prior to the founding of JAXA in 2003, ISAS worked on satellites, the National Space Development Agency of Japan (NASDA) worked on rockets and human spaceflight, and the National Aeronautics Laboratory (NAL) was responsible for flight research.

GEOTAIL’s mission was to study the Earth’s magnetic field in the area opposite the Sun, called the magnetotail. The magnetotail is the most active part of the magnetosphere because it interacts with the solar wind, which stretches the tail out. GEOTAIL was primarily an ISAS mission; NASA’s major contribution to the project was the Delta 2 launch vehicle. NASA also provided several of the spacecraft’s instruments.

An interesting connection between the Delta rocket and the Japanese space program is that Japan’s first large orbital rocket after its early converted sounding rockets was a license-built Delta first stage and boosters with a Japanese-built second stage engine. Over time, the rocket evolved into versions with more and more Japanese components, starting with a liquid hydrogen/liquid oxygen second stage.

To properly measure the magnetotail, the satellite was launched into an orbit so high that the easiest way to describe it was in terms of Earth radii instead of kilometers. The intended orbit was between 10 Earth radii at perigee and 220 Earth radii at apogee. To get there, the Delta sent GEOTAIL into a lunar flyby trajectory, stealing some momentum from the Moon to fling the satellite into a higher orbit – just like Chell in Portal. The first lunar flyby set up the trajectory for a second, pushing the apogee even further out.

GEOTAIL has accomplished a lot since it was launched on July 24, 1992. GEOTAIL flew by the Moon fourteen times between 1992 and 1994 to keep its orbit in the magnetotail as the Earth orbited around the Sun. The satellite is still operational today, with a current apogee of about 30 Earth radii.

Speaking of the Moon, Earth’s natural satellite was also used to fix the spacecraft. In 1993, one of GEOTAIL’s instruments malfunctioned and despite a lot of troubleshooting, the operations team couldn’t resolve the problem. So, the mission controllers decided to try resetting the instrument, which involved deliberately flying the spacecraft into the Moon’s shadow while disconnected from battery power in the hopes that this would force a reset. Happily, the fix worked, and the instrument started functioning again.

Huh. Sometimes unplugging something and plugging it back in really is the solution.

GEOTAIL continues to produce science thirty years after its launch. In 2016, GEOTAIL worked with NASA’s Magnetic Multiscale Mission to investigate magnetic reconnection. In this process, the magnetic field lines from different sources break and attach to each other, causing bursts of energy. And in 2018, GEOTAIL discovered special waves in the magnetic field called Kelvin Helmholz waves, which transport solar plasma and other energy to the magnetosphere.

Besides GEOTAIL’s mission in the magnetotail, the satellite has contributed to lunar science by measuring the Moon’s weak atmosphere during all those flybys.

Also this week in Rocket History, Robert Goddard launched the fourth liquid-fueled rocket ever on July 17, 1929, from his Aunt Effie’s farm in Auburn, Massachusetts. This happens to be 39 years 364 days before the launch of Apollo 11 on July 16, 1969, which is a total coincidence but is quite nice given how significant both events were.

The flight lasted just eighteen and a half seconds, which included sitting on the launch structure for thirteen seconds before the rocket started to lift, and reached an apogee of 27 meters, traveling 52.1 meters downrange. Onboard the rocket was a small camera, a thermometer, and a barometer, all of which were recovered intact after the flight, making this the first instrumented rocket launch.

Known as the Goddard 3 launch vehicle, the rocket was quite small by today’s standards, measuring just 3.5 meters in length and 66 centimeters in diameter. It weighed about 14.5 kilograms and was fueled by 6.4 kilograms of gasoline and 5 kilograms of oxygen, for a total loaded weight of 25.9 kilograms.

The flight was reportedly bright and noisy, which attracted a lot of attention and resulted in a lot of “Moon rocket” publicity.

Robert H. Goddard went on to develop increasingly sophisticated rockets before he passed away on August 10, 1945. His contributions to the field of space flight were largely unrecognized in the United States until the dawn of the “Space Age”. On May 1, 1959, NASA’s Goddard Space Flight Center in Greenbelt, Maryland was established, and on September 16, 1969, the 86th Congress authorized the issuance of a gold medal in the honor of Professor Robert H. Goddard.

More Information

This Week in Rocket History: GEOTAIL

• GEOTAIL mission page (JAXA)
• Measurements of Kelvin-Helmholtz Waves in Earth’s Magnetic Field (JAXA)
• About Magnetospheric Observation Satellite (GEOTAIL) (JAXA)
• The Magnetosphere Has a Large Intake of Solar Wind Energy (JAXA)

This Week in Rocket History: Goddard 3

• First liquid fuel rocket launched 90 years ago (Cosmos)
• Combustion Chamber, Rocket, Liquid Fuel, Robert H. Goddard, 1929 (National Air and Space Museum)