The Pluto Kuiper Express mission was a space mission designed to fly by the Pluto

Pluto

Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...

-Charon

Charon (moon)

Charon is the largest satellite of the dwarf planet Pluto. It was discovered in 1978 at the United States Naval Observatory Flagstaff Station. Following the 2005 discovery of two other natural satellites of Pluto , Charon may also be referred to as Pluto I...

 system and at least one large object in the Kuiper belt

Kuiper belt

The Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...

 beyond Pluto's orbit. Originally designated the Pluto Fast Flyby, it was scheduled to reach Pluto by 2012. The mission was cancelled for budgetary reasons, but later replaced by the similar New Horizons

New Horizons

New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...

mission.

The timing of the mission was important, as it would have passed Pluto shortly before the planet's atmosphere froze, which it does for a considerable period of the planet's orbit. The mission's main objectives would have been to map the planet's surface and examine the double system's geology and geomorphology, as well as determining the composition of Pluto's atmosphere. This last task would have been considerably more difficult after the start of atmospheric freezing. Scientific equipment on board would have included visible light imaging systems, infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 and ultraviolet

Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 spectrometer

Spectrometer

A spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...

s, and an ultrastable oscillator (USO) for use in a radio occultation experiment.

The spacecraft was to have been a simple hexagonal prism shaped structure weighing some 220 kg, powered by radioisotope thermal generators (RTGs) similar to those used on the Galileo and Cassini missions. On-board control and data collection would have been maintained by a 1.5 MIPS RISC-based computer system capable of processing data at 5 Mbit/s. This would have allowed for the transmission of over one gigabyte of data over a one year period. Communications would have been via a fixed 1.47 m high-gain antenna

High-gain antenna

A high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...

, directionally corrected using a wide-field star tracker. Early in the mission's planning there was suggestion of combining efforts with the Russian space agency and including Zond probes to study the Plutonian atmosphere. This plan was later abandoned.

The Pluto Express was predicted to be launched in 2001, but it really was ready in late 2004. The spacecraft was to have been launched via either a Delta rocket

Delta rocket

Delta is a versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. There have been more than 300 Delta rockets launched, with a 95 percent success rate. Two Delta launch systems – Delta II and Delta IV – are in active use...

 or the Space Shuttle

Space Shuttle

The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

, most likely in December 2004. Had that come to be, the only option would have been to use a Delta rocket, as the Shuttle fleet was grounded after the Columbia disaster. The course would have been initially via Jupiter

Jupiter

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

, where the planet's gravity well would have been used to increase the probe's velocity via a gravity assist. The closest approach distance to Pluto would have been about 15,000 km at 17-18 km/s, so as to allow for 1 km resolution mapping. After passing Pluto, the spacecraft would have used its imaging camera to search for Kuiper Belt objects.

External links

• New Horizons: NASA's Pluto-Kuiper Belt Mission, The Johns Hopkins University Applied Physics Laboratory
• Pluto Kuiper Express, NASA-National Space Science Data Center