Explore the Mysteries of Neptune's Magnetic Field

[relativelyslow]

hello. i am taking a planetary astronomy class and at the end there is a final project due. the project is "designing" a satellite mission within our solar system. we are to pick something (one thing) and visit it (it can be anything from asteroids to planets to moons, excluding earth, the sun, and our moon). so we have to pick a place to go, decide why its important we go there, and choose the instruments necessary (it kind of is supposed to be a mock proposal to nasa, or at least treated as such). my problem is I am not sure where to go. i was thinking going to neptune and going into the dark spot to measure wind speeds and all the particles wizzing around but that doesn't seem too interesting. i was also considering doing something with the magnetic field because it is so off center and oddly positioned but i don't know. is there anything i could do with gravity or something more astrophysically involved? any help i would be grateful for because i don't want to be stuck doing something boring, especially because a fifteen minute presentation has to be done on it. thanks again

 

[tony873004]

Visit a near-earth asteroid. You can even land on some and do a sample return mission for less fuel than landing on the moon.

Do you have a Windows based laptop computer you can use for your presentation? If so, consider using Orbiter or Celestia to make your presentation. They're both free, and they both have large communities of people in their forums that will help you set up your demo. Orbiter would probably be the better choice as you can actually pilot a spaceship to the asteroid (or Neptune if that's what you want), kinda like flying an airplane in MS Flight Simulator.

Other ideas: Go to Europa and search for live beneath the ice with radar from orbit around Europa. Go to Titan and orbit the moon with radar to map its surface in high resolution.

If you don't have a laptop to use inclass, you could always do the project at home and make a bunch of screenshots.

 

[marlon]

In college i once had to make a project of a sattelite mission to Mars (The Rosetta sattelite, i am sure you have heard of it). We had to calculate the minimal distance this sattelite had to have above the earth, so it would get to Mars via gravity assists. It is important to realize that you don't just fire off some object along the shortest trajectory to your destination. That costs far to much energy.

The trick is to use gravity assists and take energy from gravitational interaction between the sattelite and the planet. This interaction not only changes the trajectory but also gives more kinetic energy to the sattelite. You know that both angular momentum and total energy are conserved in such interactions. In my project, Rosetta was launched from the eart, went around the sun, back to the earth, then the Earth changed it's trajectory towards Mars.

We had to calculate the date, initial velcoty and time of arrival at Mars.

regards
marlon

 

[tony873004]

Using Marlon's Rosetta example, here's a thread in the Orbiter forum where I made a Rosetta scenerio as it flew by the Earth. http://orbit.m6.net/v2/read.asp?id=22334

This is the type of thing I had in mind when I suggested you use Orbiter. Just bring in 8.5x11 printouts of your screen shots, and a nice talk to narrate what's going on.

Interesting to note that if you speed up the simulation and wait a few years, Rosetta actually does pass Mars. Not quite as close as the real Mars flyby because the real Rosetta probably has a small correction maneuver in its schedule.

The screen shots in the above link are from Orbiter and Gravity Simulator. Gravity Simulator let's you play with the position and watch how different flyby distances yield different results. So you can actually get your answer without doing any math!

 

[relativelyslow]

here is the basic instruction of the project:

Background:

"You have been selected as part of a group of investigators competing to build one of NASA new Discovery Program satellites. In line with the "faster, cheaper, better" philosophy of space exploration Discovery satellites are required to be low cost with fast development times so that many smaller missions can be launched. Proposals require careful tradeoffs between science and cost to produce investigations with the highest possible science value for the price.

As a planetary scientist you are a member of the science planning team. Therefore you are only working on the instrument package that will be included with the spacecraft . Propulsion, power, communications, etc. will be handled by other teams. Focus primarily on what the spacecraft should investigate and what equipment it will use to do so.

However, to stay within budget, the engineering teams have given you a few constraints. You must achieve your objectived with no more than a total mass of 200 kilograms (kg) in instruments and a total power requirement of no more than 150 Watts (W). Succeed and your career is assured! Fail and ... well, that's not really an option, is it?"


so although figuring out the satellite's path using gravity assists would be cool, its not really what I am suppose to do (it would be awesome to design it in its entirety but, unfortunately, we don't really get into physics). i was thinking more like gravity waves or something (using peizoelctricity perhaps), but I am not sure that would give me any useful information. is there anything that measuring heat output would be useful? would looking at the odd magnetic field of neptune or uranus yield anything about the formation of magnetic fields in planets or is that long ago discovered? I am trying to figure out something to measure that would be applicable to other places because that would add to its importance (instead of something only useful for that place). I am not sure what else i could do.

about the computers i think we are supposed to use one; i think powerpoint was suggested. one more regulation: i can have either a rover OR an orbiter, not both. thanks for the suggestions so far. i will think about them. (is there anything in our solar system other than planets, moons, asteroids, and comets?)

 

[marlon]

Tony, nice project. You get 6500km as the closest distance between Rosetta and the earth, right ? I got about 5700km

Can you give me some more info on this gravity simulator ?

marlon.

 

[tony873004]

Tony, nice project. You get 6500km as the closest distance between Rosetta and the earth, right ? I got about 5700km

Can you give me some more info on this gravity simulator ?

marlon.

No, I get a lot closer. The 6500 figure in that thread is for Rosetta when it is still 20 minutes to closest approach. Look at the 4th screen shot. This is the "dashboard" of the hypothetical craft that I used to represent Rosetta since no one has made a Rosetta add-on yet. The number in the right MFD (multi-functional display) Next to RAD is 8.333M. This means 8.333 million meters, or 8.333 thousand kilometers. Subtract Earth's radius from this 8333-6378 = 1955 kilometers as this screen shot was taken. If you look at the left MFD, you'll see that I still have -34.4 m/s of vertical speed (towards the Earth), so I jumped the gun by a few seconds on taking my screen shot, and my actual closest distance is probably a little closer than 1955 km. This agree nicely with ESA's figure. Only 5 more kilometers before our numbers agree when rounded to the same number of digits.

by http://rosetta.esa.int/science-e/www/object/index.cfm?fobjectid=36505
On 4 March 2005, Rosetta will perform its first Earth swing-by. Closest approach will occur around 22h10 UT, when the spacecraft will be 1900 km from the surface.

Gravity Simulator is a program I wrote ( www.gravitysimulator.com ). In this Rosetta simulation, I obtained positions and velocity vectors from JPL Horizons to create the simulation. Just like the Orbiter version, if you speed it up, you can watch Rosetta fly past Mars about 2 years after the Earth flyby. In Gravity Simulator, you can do it much faster though (under 30 seconds) instead of about 10 minutes in Orbiter since Gravity Simulator is drawing pixels, and Orbiter is actually drawing the planets.

 

[relativelyslow]

any more suggestions?

 

[Chronos]

A comet interceptor would a fun project. Design a probe to intercept and return with samples from an interesting target - much like the asteroid idea tony mentioned. Kuiper belt objects are of great interest, probably more so than planets. You could intercept it on the inbound trajectory, hitchhike around the sun and return as it swung back past earth. It would be quite novel, anyways, and instructors are suckers for that sort of thing.

 

[tony873004]

Visit Sedna!

There is a theory that suggests Sedna might not originally be from our solar system. A flyby visit could potentially answer this question and this may be a unique opportunity to visit something of exosolar origin.

Google for Alessandro Morbidelli and Harold F. Levison. They have 2 Sedna theories, one of which is that Sedna was captured by the Sun.

Even though Sedna was only discovered last year, you can Google enough stuff to do a 1 hour presentation. Shouldn't be too hard to fill 10 minutes.

 

[Nereid]

1) Triton - magnetic, optical, IR, ... a close pass would surely give us much to contextualise the Voyager results
2) Pluto/Charon - almost anything! atmospheres, mag fields, surface details, ...
3) Any of the Centaurs - proto-comets? mini-Tritons/Plutos? what??
4) Io - radiation hardening a must! But if others are doing the lander/close flyby aspects, why not magnetics/surface composition/atmosphere/etc?
5) the equivalent on Saturn of the Galileo descent probe
6) ditto, Uranus or Neptune
7) kamikaze through a ring system - Saturn the best, but Jupiter, Uranus, or Neptune would also be good (think Giotto)
8) kamikaze into/through the Sun's corona - solve 'coronal heating' once and for all!
9) slingshot out to the heliopause - now that Voyager has been killed, we'll never know!
10) (wildchild) the universe at ELF/ULF - the inner solar system is opaque; every new window brings unexpected discoveries! (considerable creativity required re imaging).