Mission to the Sun

A mission to the sun is difficult stuff. For 30 years scientists and engineers have struggled with developing a spacecraft that could survive the harsh environment close to the sun, but always ended up running into insurmountable technology limitations or blowing the top off the budget. But now the Applied Physics Lab believes they have come up with a plan that will work, and NASA has given them the go-ahead to get a mission ready by 2015. And contrary to the old joke about a mission to the sun, the new Solar Probe won’t have an easy time of it by just heading to the sun at night!

The Solar Probe mission will come within 6.6 million kilometers (4.1 million miles) of the sun to study the streams of charged particles the sun hurls into space. The spacecraft will actually be within the sun’s corona — its outer atmosphere — where the solar wind is produced. At closest approach the Solar Probe will zip past the sun at 210 km (125 miles) per second, protected by a carbon-composite heat shield able to withstand up to 1425 degrees Celsius (2,600 degrees Fahrenheit) and survive blasts of radiation and energized dust at levels not experienced by any previous spacecraft.

The spacecraft will weigh about 1,000 pounds. Preliminary designs include a 2.7 meter (9 feet) diameter, 15 centimeter (6 inches) -thick, carbon-foam-filled solar shield atop the spacecraft body, similar to APL’s MESSENGER spacecraft.

The probe will be solar powered (no problem there!) with two sets of solar arrays that will retract or extend as the spacecraft swings toward or away from the sun during several loops around the inner solar system, making sure the panels stay at proper temperatures and power levels. At its closest passes the spacecraft must survive solar intensity more than 500 times what spacecraft experience while orbiting Earth.

“Solar Probe is a true mission of exploration,” says Dr. Robert Decker, Solar Probe project scientist at APL. “For example, the spacecraft will go close enough to the sun to watch the solar wind speed up from subsonic to supersonic, and it will fly though the birthplace of the highest energy solar particles. And, as with all missions of discovery, Solar Probe is likely to raise more questions than it answers.”

Solar Probe will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the sun, coming as close as 4.1 million miles to the sun, about eight times closer than any spacecraft has come before.

The main goals of the Solar Probe are to determine the structure and dynamics of the sun’s magnetic field, trace the flow of energy that heats the corona and accelerates the solar wind, and explore dusty plasma near the sun and its influence on solar wind and energetic particle formation. This mission will also help us learn more about the sun-Earth relationship.

Original News Source: Eureka Alert

21 Replies to “Mission to the Sun”

  1. Wonderful to see a mission going deep into the corona. There are so many secrets that can only be uncovered by sending a probe to measure plasma waves and particle interactions in-situ it’s not funny! This mission would rewrite the solar history books providing a much-needed look into the small-scale interactions to begin understanding the large scale observations. Fantastic!

    Whether we are looking at distances in Imperial or SI, this really shouldn’t distract from a wonderful article stuffed full of enthusiasm for this great mission. I think ferlongs per fortnight might be a good call John, as a Brit myself I can even work in inches per fortnight… we’re a dynamic bunch 😉

    Oh yes, and Jorge, the Venus flybys will be needed to get the probe up to speed. As it will be getting pretty damned close to the Sun, it will need to be flying VERY fast to get it into a stable orbital trajectory. Will be nice if it can do some science around Venus, but this will most likely be in the form of analysing the interplanetary space rather than doing any planetary observations.

    This kind of mission gives me the insentive to get back into solar research!

    Nice one Nancy!

    Cheers, Ian 🙂

  2. Hi Steve:

    1) Those are particle temperatures and relates more to their velocities (i.e. spectroscopic measurements) – keeping in mind the environment of the corona is more tenuous than the best vacuum we can attain here on Earth, it’s not like the probe will be boiled in a thick soup of plasma. The biggest problem will come from the EM radiation. As the intensity of solar light drops off with distance (1/r2), the ravages of the Sun at 4.1 million miles away will heat the probe to a couple of thousand Kelvin. It’s not the solar particles that can cause the damage, it’s the radiation.

    2) They will be exposed to the Sun, but during periods when it is at a safe enough distance – during close approach they will be retracted.

    3) It might get hit by a CME, but i’m sure the engineers will account for this. This risk can be reduced by sending the probe out at solar minimum, when activity is low…

    hope that helps!

    Cheers, Ian 🙂

  3. Miles per second, fahrenheit, pounds, feet, inches… sheesh!

    At the very least convert these for the world at large that uses SI. We are actually the VAST majority out here. Not sure about the blog readers, but we might even be also a majority there.


  4. Well I hope their not BS’ing about the heat shield. If their just hoping it will hold up to that kind of enviroment, I wouldn’t hold my breath long. The good part is, if it does, it might give N.A.S.A. an idea about how to shield space craft for lunar missions to be safe enough for men to go and work on the moons surface with out danger of radiation exposure.

  5. Could be worse. The sight is British. How about furlongs per fortnight?

  6. Maybe you can spend the time converting the measurements to the standard of your choice and exercise some gray matter in the process.

  7. Dude, if you can’t understand that a blog, such as this one, that writes for the widest possible audience should take care to perform and present routinely data that this widest possible audience will immediately understand, then it’s not me who needs gray matter excersise.

    If you used your brain for something other than being a brat, kerouac-wannabe, you might understand this simple fact.

  8. Have you noticed that no comments about the mission have been posted? And that is a simple fact.

  9. True. So here’s a question about the mission: are those Venus flybys just navigational, or are they supposed to generate some Venus science in the process?

  10. q1: This article states that the craft will actually be within the Sun’s corona. On the soho site, it says that the corona can be up to 2 million degrees f. Is the 4.1 million miles far enough away that the 2600 deg f heat shield is enough insulation?

    q2: how will the solar panels collect their power if they have to hide behind the heat shield.

    q3: is there data as to probability of getting hit by a cme? (I’m thinking statistics similar to the Wylie data for lighning strikes here on Earth).

  11. To answer a few questions here:

    The Venus flyby is used to shrink the spacecraft’s orbit around the sun. It’s too early to say what science, if any, would be done at Venus, but a flyby always offers the chance to test out your science instruments.

    According to the info available about this missions so far, 2600 degrees is what they are expecting as the highest temps the spacecraft would have to withstand.

    The solar arrays would retract or extend as the spacecraft swings toward or away from the sun.

    I don’t have data right at my fingertips about the probability of taking a hit from a CME, but it might be out there somewhere on the information superhighway. Anyone else have time to take a look?

  12. Una misión al Sol es un asunto complicado. Durante 30 años los científicos e ingenieros han luchado para desarrollar una nave espacial que pudiera sobrevivir al duro ambiente en las inmediaciones del Sol, pero siempre terminaron en limitaciones insuperables de la tecnología o excediendo el presupuesto. Pero ahora […] Fuentes: Nancy Atkinson para Universe Today y EurekAlert!

  13. Frankly, I live in the United States and I’d rather see things in metric too. Leave it to us to be wonky.

  14. Wake Up People, all these missions are money wasted–lets take care of the Earth that we live on and leave the rest to God Almighty.
    People on Earth on slaving their azz off to pay taxes to send to Mars, no wonder gasoline is so high, it is going into space.

  15. # WAKE UP Says:
    May 5th, 2008 at 6:47 pm

    “Wake Up People, all these missions are money wasted–lets take care of the Earth that we live on and leave the rest to God Almighty.
    People on Earth on slaving their azz off to pay taxes to send to Mars, no wonder gasoline is so high, it is going into space.”

    The fact that missions such as these go ahead is awesome. The fact that that pisses you off ‘WAKE UP’ makes me even happier. Probably twice as happy, actually. Oh, glorious day!

  16. Wake Up, why not let “God Almighty” take care of the Earth, or is “God Almighty” an absentee landlord?

    This is a much better use of tax payers money than making million dollar bombs.

    I say we all go and look at the Bollywood links from aju. 😉

  17. The Almighty gave us brains to explore the solar system for almost no money at all (compared to how much is being wasted on bad movies, cosmetics, wars etc) so we should heed this indirect calling. It’s a perfect opportunity to learn more about the Creation and praise its Creator. If not for any other reason, a challenge like this gives new technologies for use on Earth and new jobs which in turn produce tax money. WAKE UP: go back to sleep!

    Anyway, it will be a wonderful mission if it can go ahead. So much in our lives depends on the Sun it should be somewhere near the top of our agenda to research our local star as much as possible.

    Kind regards,

  18. Adam… Well said! 🙂


    Wake up… don’t judge our actions, and we won’t judge yours.

    Unfortunately, your statement shows how you have trouble relating one public issue with another (fuel cost/space exploration). I’m sorry you are so misinformed and confused.

    I will not fault you if you send a note to the tax man, and request that your personal tax dollars are not used on this mission. There are a lot of us who are all for it.

Comments are closed.