List of artificial objects escaping from the Solar System
Below is a list of artificial objects escaping from the Solar System. All of these objects are space probes and their upper stages launched by NASA, the United States space agency, and do not include those missions that went into orbit around planets.
- Pioneer 10 – Launched in 1972, flew past Jupiter in 1973. Contact lost in January 2003 and is heading in the direction of Aldebaran in Taurus.
- Pioneer 11 – Launched in 1973, flew past Jupiter in 1974 and Saturn in 1979. Contact lost in November 1995. The spacecraft is headed toward the constellation of Aquila (The Eagle), Northwest of the constellation of Sagittarius. Barring incident, Pioneer 11 will pass near one of the stars in the constellation in about 4 million years.
- Voyager 2 – Launched in August 1977, flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. Probe has (depending on the source) not passed the heliosheath, but is still active.
- Voyager 1 – Launched in September 1977, flew past Jupiter in 1979 and Saturn in 1980, making a special close approach to Saturn's moon Titan. Probe passed the heliopause on 25 August 2012 to enter interstellar space, and is still active.
- New Horizons – Launched in 2006, probe made flyby of Jupiter in 2007, will make a flyby of Pluto in 2015. Flyby of Pluto may be followed by a flyby of a Trans-Neptunian object in the Kuiper belt.
- New Horizons third stage, a STAR-48 booster, is on a similar escape trajectory out of the Solar System as New Horizons, but will pass millions of miles from Pluto. It will probably cross Pluto's orbit in late 2015.
The only objects to date to be launched directly into a solar escape trajectory were the New Horizons spacecraft, its third stage and its two small de-spin masses. The New Horizons Centaur stage is not escaping, it is in a 2.83-year orbit.
Many of the upper stages of all these spacecraft except Pioneer 11 are also escaping the Solar System as they initially followed a trajectory very close to that of their respective spacecraft and their subsequent encounters with Jupiter boosted them all into hyperbolic solar escape trajectories. The upper stage of Pioneer 11 is believed to be in solar orbit because its encounter with Jupiter would not have resulted in escape. Pioneer 11 gained the required velocity to escape the Solar System in its subsequent encounter with Saturn.
Since the Pioneers were launched first, they had a head start on the Voyagers, but because they were traveling slower they were eventually overtaken for most distance from the Sun: Voyager 1 passed Pioneer 10 on February 17, 1998.
- NASA - The Pioneer Missions
- "Voyager 1 finally crosses into interstellar space", William Harwood, CBS News, 2013-09-12 
- Alan Stern and Yanping Guo - Where Is the New Horizons Centaur Stage? (October 28, 2010) - NASA
- Derelict Booster to Beat Pluto Probe to Jupiter
- Voyager: Fast Facts (NASA)
- Spacecraft escaping the Solar System in heavens-above.com