Interstellar Probe (1999)

{{short description|1999 NASA space probe concept}}

{{Infobox spacecraft class

| name = Interstellar Probe

| image = Interstellar robotic probe.gif

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| image_caption = Concept art for the proposed spacecraft, backdropped by stars

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| operator = NASA

| applications = To travel out 200 AU in 15 years

| spacecraft_type = Space probe

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| power = Solar sail

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| diameter = 400m

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Interstellar Probe is the name of a 1999 space probe concept by NASA intended to travel out 200 AU in 15 years. This 1999 study by Jet Propulsion Laboratory is noted for its circular 400-meter-diameter solar sail as a propulsion method (1 g/m2) combined with a 0.25 AU flyby of the Sun to achieve higher solar light pressure, after which the sail is jettisoned at 5 AU distance from the Sun.{{cite book|url=http://www.nap.edu/read/11135/chapter/6#31|title=4 An Interstellar Probe to the Boundaries of the Heliosphere and Nearby Interstellar Space - Exploration of the Outer Heliosphere and the Local Interstellar Medium: A Workshop Report - The National Academies Press|year=2004|publisher=|doi=10.17226/11135|isbn=978-0-309-09186-2}}

Solar sail

Solar sails work by converting the energy in light into a momentum on the spacecraft, thus propelling the spacecraft.{{cite web|url=https://www.newscientist.com/article/dn18141-propelled-by-light-the-promise-and-perils-of-solar-sailing/|title=Propelled by light: the promise and perils of solar sailing|work=New Scientist |date=11 November 2009 |first=Macgregor |last=Campbell}} Felix Tisserand noted the effect of light pressure on comet tails in the 1800s.

The study by the NASA Jet Propulsion Laboratory proposed using a solar sail to accelerate a spacecraft to reach the interstellar medium. 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.{{cite web |url=http://interstellar.jpl.nasa.gov/interstellar/probe/index.html |title=Interstellar Probe |publisher=Interstellar.jpl.nasa.gov |url-status=dead |archiveurl=https://web.archive.org/web/20090731141905/http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/intro.html |archivedate=2009-07-31 |access-date=2015-10-09 }} A critical technology for the mission is a large 1 g/m2 solar sail.

{{pquote|This great journey requires advanced propulsion, and the 200-kg Interstellar Probe is designed to use a 200-m radius solar sail to achieve a velocity of 14 AU/year. After exiting the heliosphere within a decade of launch, it would be capable of continuing on to ~400 AU. Interstellar Probe would serve as the first step in a more ambitious program to explore the outer solar system and nearby galactic neighborhood.|Interstellar Probe, 1999{{cite web|url=http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/intro.html|archive-url=https://web.archive.org/web/20030406115605/http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/intro.html|url-status=dead|archive-date=2003-04-06|title=NASA IP|publisher=}}}}

In the following years there were additional studies, including the Innovative Interstellar Explorer (published 2003), which focused on a design using RTGs powering an ion engine rather than a solar sail. Another project in this field for advanced spaceflight during this period was the Breakthrough Propulsion Physics Program which ran from 1996 through 2002.

Later examples of solar sail-propelled spacecraft include IKAROS, Nanosail-D2, and LightSail.{{cite web|url=http://www.nbcnews.com/science/space/lightsail-space-mission-will-shine-global-spotlight-solar-sails-n361601|title=LightSail Space Mission Will Shine Global Spotlight on Solar Sails|work=NBC News |date=May 19, 2015 |first=Alan |last=Boyle}} Near-Earth Asteroid Scout is a planned light sail-propelled mission.{{cite web|url=http://space.skyrocket.de/doc_sdat/nea-scout.htm|title=NEA-Scout|website=space.skyrocket.de}} For comparison, the LightSail spacecraft uses a sail 5 micron in thickness, whereas they predict a sail with 1 micron thickness would be needed for interstellar travel.

Other design features

The probe would use an advanced radioisotope thermoelectric generator (RTG) for electrical power, Ka band radio for communication with Earth, a Delta 2 rocket for Earth launch, and a 25 kg instrument package using 20 watts.

Objectives

{{wideimage|Interstellar Probe Objectives.gif|500px|NASA produced diagram relating science goals to each region with regions farther from the Sun to the right. One AU is the distance from about the Sun to the Earth. Both Voyager 1 and 2 have passed 100 AU already. Yellow-orange color bar indicates the radial region where measurements are possible; the deepest orange is the prime region of interest.}}

Historical view of region

{{wideimage|Interstellar Probe and Heliosphere Diagram.gif|500px|This is a look at the region the probe would fly through as it was predicted at the time}}

See also

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References

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