Nuclear Powered Mission To Neptune In 30 Years?

[zavvy]

<b>Nuclear Powered Mission To Neptune In 30 Years?</b><br /><br />LINK<br /><br />In 30 years, a nuclear-powered space exploration mission to Neptune and its moons may begin to reveal some of our solar system's most elusive secrets about the formation of its planets -- and recently discovered ones that developed around other stars. This vision of the future is the focus of a 12-month planning study conducted by a diverse team of experts led by Boeing Satellite Systems and funded by NASA. It is one of 15 "Vision Mission" studies intended to develop concepts in the United States' long-term space exploration plans. Neptune team member and radio scientist Professor Paul Steffes of the Georgia Institute of Technology's School of Electrical and Computer Engineering calls the mission "the ultimate in deep space exploration." <br /><br />NASA has flown extensive missions to Jupiter and Saturn, referred to as the "gas giants" because they are predominantly made up of hydrogen and helium. By 2012, these investigations will have yielded significant information on the chemical and physical properties of these planets. Less is known about Neptune and Uranus -- the "ice giants." <br /><br />"Because they are farther out, Neptune and Uranus represent something that contains more of the original – to use a 'Carl Saganism' – 'solar stuff' or the nebula that condensed to form planets," Steffes said. "Neptune is a rawer planet. It is less influenced by near-sun materials, and it's had fewer collisions with comets and asteroids. It's more representative of the primordial solar system than Jupiter or Saturn." <br /><br />Also, because Neptune is so cold, its structure is different from Jupiter and Saturn. A mission to investigate the origin and structure of Neptune -- expected to launch between 2016 and 2018 and arrive around 2035 -- will increase scientists' understanding of diverse planetary formation

 

[odysseus145]

There is an SDC article today:<br />http://www.space.com/businesstechnology/technology/neptune_orbiter_techwed_041215.html<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[spacester]

Neptune is HARD! Over 20 years transit time for Hohmann and the departure deltaV alone is comparable to getting from Earth's surface to LEO<br /><br />Here are the essential numbers from my Solar System Planner program. <br /><br />This first set is for a theoretical flight from Earth's center to Neptune's center, ignoring the gravity wells of the planets themselves.<br /><br />Away transfer insertion date is ........ 2005-APR-11 07:11:11<br />Orbital insertion at destination date is 2035-JUN-02 20:43:17<br />Time of flight away mission is 11009.5640 days, Hohmann flight<br />***Delta V values corrected for eccentric planetary orbits***<br />Delta V for away mission, burn 1 = 11.6858 km/sec<br />Delta V for away mission, burn 2 = 4.0829 km/sec<br />Delta V for away mission, Total = 15.7687 km/sec <br /><br />This second set is for transfer between LEO and HENO (Highly Elliptical Neptune Orbit)<br /><br />Away transfer insertion date is ........ 2005-APR-11 07:11:07<br />Orbital insertion at destination date is 2035-JUN-02 20:43:04<br />Time of flight away mission is 11009.5639 days, Hohmann flight<br />***Delta V values corrected for eccentric planetary orbits***<br />***Delta V values corrected for parking orbits around planets***<br />*Parking orbit at origin prior to away trip:<br /> Periapse altitude= 375 km, Apoapse altitude= 400 km<br />*Parking orbit at destination after away trip:<br /> Periapse altitude= 500 km, Apoapse altitude= 50000 km<br />**Target altitude at destination (impact parameter) = 121097 km<br />Delta V for away mission, burn 1 = 8.2394 km/sec<br />Delta V for away mission, burn 2 = 3.5050 km/sec<br />Delta V for away mission, Total = 11.7444 km/sec <div class="Discussion_UserSignature"> </div>

 

[odysseus145]

Without the use of either parachutes or rockets, how can they land a probe on Triton? <div class="Discussion_UserSignature"> </div>

 

[mikejz]

How would a Jupiter flyby help these numbers?

 

[thalion]

If they hadn't axed a proposed Neptune orbiter in the early 90s, we could have had 15 years up on 2035. But I digress.<br /><br />The best option, IMO--but also by far the riskiest--is to pull off an aerocapture maneuver. Twenty years is rather long to ask any scientist--let alone the public--to wait. But would it be worth the wait to have a Triton lander and a bevy of atmospheric probes, plus potentially decades of <i>in situ</i> study? That's a tough call...I'd have to err on the side of "yes."<br /><br />That said, I have an idea for aerocapture that might minimize the risk, IMO. Launch two spacecraft on identical trajectories. Craft 1 would arrive a few weeks ahead of the main Craft 2. A simple test vehicle with minimal instrumentation, it would have an aeroshell / heat shield, and would enter the atmosphere at the same latitude and same local time as the main probe. The engineers would try to use aerocapture on the first craft to see if they have the physics and trajectory right, based on their atmospheric model. It's a win-win situation; if they lose Craft 1, they know they're doing something wrong, and can make sure they don't repeat it with the main craft. If Craft 1 is successfully aerocaptured, then they have a scientific bonus, and can know they're doing something right.<br /><br />I agree with one point on the SDC article, though; they should definitely try this out with a cheap Mars or even Venus mission first, before cashing in all their chips 30 AUs and 10-15 years from home.

 

[chmee]

I think aerocapture is a great idea, it should would save a ton propellant and time! There are risks, especially not knowing exactly the characteristics of Neptune's atmosphere. Maybe we should try it first with a Mars orbiter.<br /><br />Hell, aerocapture worked in the movie/book 2010: Odyessy Two with Jupiter <img src="/images/icons/smile.gif" />