Interstellar Probe - Proposed Interstellar Probes

Proposed Interstellar Probes

Missions intended to reach the interstellar medium.

Innovative Interstellar Explorer (2003+)

NASA proposal to send a 35 kg science payload out to at least 200 AU. It would achieve a top speed of 7.8 AU per year using a combination of a heavy lift rocket, Jupiter gravitational assistance, and an ion engine powered by standard radioisotope thermal generators. The probe suggested a launch in 2014 (to take advantage of Jupiter gravitational assist), to reach 200 AU around 2044.

Realistic Interstellar Explorer & Interstellar Explorer (2000–2002)

Studies suggesting various technologies including Am-241-based RTG, optical communication (as opposed to radio), and low-power semi-autonomous electronics. Trajectory uses a Jupiter and Sun gravity assist to achieve 20 AU/year, allowing 1000 AU within 50 years, and a mission extension up to 20 thousand AU and 1000 years. Needed technology included advanced propulsion and solar shield for perihelion burn around the Sun. Solar thermal (STP), nuclear fission thermal (NTP), and nuclear fission pulse, as well as various RTG isotopes were examined. The studies also included recommendations for a solar probe (see also Solar Probe Plus), nuclear thermal technology, solar sail probe, 20 AU/year probe, and a long term vision of a 200 AU/year probe to the star Epsilon Eridani.

The "next step" interstellar probe in this study suggested a 5 megawatt fission reactor utilizing 16 metric tonnes of H₂ propellant. Targeting a launch in the mid-21st century, it would accelerate to 200 AU/year over 4200 AU and reach the star Epsilon Eridani after 3400 years of travel in the year 5500 AD. However, this was a second-generation vision for a probe and the study acknowledged that even 20 AU/year might not be possible with then current (2002) technology. For comparison, the fastest probe at the time of the study was Voyager 1 at about 3.6 AU/year (17 km/s), relative to the Sun.

Interstellar Probe (1999)

Interstellar Probe was a proposed solar sail propulsion spacecraft planned by NASA Jet Propulsion Laboratory. It was planned to reach as far as 200 AU within 10 years at a speed of 14 AU/year (about 70 km/s), and function up to 400+ AU. A critical technology for the mission is a large 1 g/m2 solar sail. The probe itself hoped to use an advanced RTG for electrical power, Ka-band radio for communication with Earth, Delta 2 for Earth launch, and a 25 kg instrument package using 20 watts.

(Mewaldt et al., 1995)

Study for 200 kg probe traveling at 6 to 14 AU/ year using chemical and planetary or solar gravity assists.

(Holzer et al., 1990)

Study for 1000 kg probe traveling at 10 AU/year using chemical and a solar gravity assist, to collect data out to 200 AU from the Sun.

TAU mission (1987)

TAU mission (Thousand Astronomical Units) was a proposed nuclear electric rocket craft that used a 1 MW fission reactor and an ion drive with a burn time of about 10 years to reach a speed of 106 km/s (about 20 AU/year) to achieve a distance of 1000 AU in 50 years. The primary goal of the mission was to improve parallax measurements of the distances to stars inside and outside of our galaxy, with secondary goals being the study of the heliopause, measurements of conditions in the interstellar medium, and (via communications with Earth) tests of general relativity.

Interstellar Precursor Mission (Jaffe, 1977–1979)

Proposed nuclear electric power/propulsion for a probe to 370 AU in 20 years and 1030 AU in 50 years from launch.