Author Topic: Parker Solar Probe - post-launch Discussion and Updates  (Read 13812 times)

Online jebbo

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A thread for updates on the post-launch, science phase of the mission

Timeline (incomplete)
12 Aug 2018Launch
3 Oct 2018Venus Flyby #1
5 Nov 2018Perihelion #1
4 Apr 2019Perihelion #2
1 Sep 2019Perihelion #3
26 Dec 2019Venus Flyby #2

--- Tony
« Last Edit: 10/02/2018 06:08 PM by eeergo »

Offline jbenton

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #1 on: 08/23/2018 09:07 AM »
Since you labeled this as a discussion and updates thread, and since it will be some time until the next major event, I thought I'd ask:

Does anyone know much about the history of this probe?

Specifically, I'm interested in knowing how the Parker Probe compares to the older concept back in the early 2000's. My understanding is that the original concept had the perihelion even closer than the current design, and explored the Sun's poles, but the aphelion was all the way past Jupiter (it would've used an RTG):

https://en.wikipedia.org/wiki/Parker_Solar_Probe

Admin. O'Keefe thought it was too expensive, so NASA cancelled it. But then Congress intervened. This is from page 6 in the Proposed Europa Missions thread:

   Here is a link to an update on the status of the Europa Clipper mission.  I wrote it as a guest on Van Kane's "Future Planetary Exploration" website. 

http://futureplanets.blogspot.com/2013/05/europa-clipper-update.html

I hope that it answers some questions about the mission.

Quote
How this will turn out is difficult to gauge.  This is not the first time such a struggle has occurred.  For years, the Congress earmarked funds for development of a Solar Probe mission.  Eventually, NASA got the message and awarded a new start for the Solar Probe Plus spacecraft.  About 10 years ago, when NASA was trying to eliminate funding for the New Horizons Pluto probe, Congress specifically earmarked funding for that mission...


Good reference to Solar Probe. I had forgotten about that. There's a good story behind the creation of Solar Probe Plus. My limited understanding/memory is that Congress kept putting money in the budget for that but NASA kept ignoring them. NASA just did not think that they could afford Solar Probe. Finally, Alan Stern said to that community (this is almost a direct quote from a talk he gave) "Do you want 100% of nothing or 80% of something?" And he forced them to redesign Solar Probe into a mission that NASA could afford and got a new start on it.

... and with that, they de-scoped it into it's present form with solar panels and Venus flybys.

My question, then is threefold:

1) Can anyone expand on this narrative?
2) Would the science of the original mission plan really be demonstrably better in any measurable way?
3) How much more would this have cost? (adjusted for inflation, please :) ) If I'm not mistaken the Parker Solar Probe cost NASA ~$1.5 billion

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #2 on: 08/23/2018 11:26 AM »
An earlier version had 3 RTGs. I saw a large scale model of it at a conference ca 2006. That would have added a lot to the cost (over $100 million, I think). One of the things that Alan Stern did during his short term as AA for science was tell the heliophysics community (I heard him say this) "Do you want 80 percent of something or 100 percent of nothing?" His point was that they had been trying forever to get the mission funded and it was not happening, so they needed to change their science goals to come up with a more affordable mission.

You should also look at the relevant heliophysics decadal surveys to see how the mission was explained and prioritized. Understanding what the science goals were tells you a lot about how the mission design changed.

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #3 on: 08/23/2018 11:37 AM »
Some examples. I'm not sure this is the configuration that I saw in model form around 2006. The concept design has changed many times over many decades.

Offline jbenton

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #4 on: 08/23/2018 11:43 AM »
That thing looks epic!!!


Of course that's also exactly what I thought the first time I saw the design for the Parker Solar Probe - then known as "Solar Probe Plus"   8)

Offline Star One

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #5 on: 08/23/2018 12:11 PM »
Common sense would question why you would even come up with a design needing RTGs when you’re going towards the source of all Solar Power. Surely they are only needed when there isn’t enough sunlight for solar panels. Unless you’re trying to fly a design that includes everything plus the kitchen sink so to speak and think budgets are unlimited.
« Last Edit: 08/23/2018 12:43 PM by Star One »

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #6 on: 08/23/2018 12:26 PM »
That thing looks epic!!!


Of course that's also exactly what I thought the first time I saw the design for the Parker Solar Probe - then known as "Solar Probe Plus"   8)

I think that PSP is in many ways more interesting. If you look at how they designed the solar panels with that little lip on the end to get power when they are fully stowed, it's a pretty cool solution to a hellish environment.

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #7 on: 08/23/2018 12:28 PM »
Also, somewhere there is a graphic showing about 10 different Solar Probe design concepts dating from the 1980s to the 2000s. That might have even been posted here, so go looking for it. And I think I also posted the very first Solar Probe concept design here, dating from the early 1960s. It was simply a box with a big shield out front. See if you can find it, and if you do, you could re-post it to this thread.

Offline zhangmdev

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #8 on: 08/23/2018 12:37 PM »
Lots of info about the Solar Probe

https://solarprobe.gsfc.nasa.gov/solarprobe_apl_study.pdf

The original orbit is very elongated. The spacecraft has to endure cold environments of outer plants as well as very hot conditions close to Sun. Two thermal shields and three MMRTGs. The primary shield is 2.7 m indiameter and 5 m in height, 121 kg in mass. It has to withstand thrust loads to 20 G. That is going to be very difficult.
« Last Edit: 08/23/2018 12:38 PM by zhangmdev »

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #9 on: 08/23/2018 01:12 PM »

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #10 on: 08/23/2018 02:20 PM »
Now I vaguely seem to remember that the model that I saw in 2006 was a smaller version of the 3-RTG spacecraft in the images above. I think that the early 2000s Solar Probe was still too big and expensive, and so they tried to force it down and that meant removing some instruments. But even that one required the 3 RTGs and that was still expensive.

Solar Probe is another example of how initial cost estimates can be wrong. I believe that over a decade ago the mission was rejected because it was going to cost something like $1.5 billion. So they went back to the drawing board and scaled it back, got rid of the RTGs, etc. And in the end, the scaled-back mission still cost something like $1.6 billion.

Offline Welsh Dragon

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #11 on: 08/23/2018 05:43 PM »
Common sense would question why you would even come up with a design needing RTGs when you’re going towards the source of all Solar Power. Surely they are only needed when there isn’t enough sunlight for solar panels. Unless you’re trying to fly a design that includes everything plus the kitchen sink so to speak and think budgets are unlimited.
Several of the early concepts had a Jupiter flyby like Ulysses.

Offline Zed_Noir

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #12 on: 08/23/2018 05:59 PM »
Wonder if there will be a follow-on mission study in the next few decadal surveys?

Something more like the early Solar Probe Plus designs prior to the descoping or something similar to the current PSP design in terms of observation objectives?

Offline zhangmdev

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #13 on: 08/23/2018 07:01 PM »
ESA has planned the Solar Orbiter, close to PSP but less ambitious

http://sci.esa.int/solar-orbiter/44168-spacecraft/

Offline whitelancer64

Wonder if there will be a follow-on mission study in the next few decadal surveys?

Something more like the early Solar Probe Plus designs prior to the descoping or something similar to the current PSP design in terms of observation objectives?

If PSP doesn't sufficiently answer the coronal heating questions, or does so while raising a large subset of new questions, then a follow-on might be worth it.

A set of solar probes that could be flown in a constellation to measure the changes in the Sun's magnetic fields, like the Van Allen belt probes do for the Earth, would be extremely facinating.

And I've always wanted to see a follow-on for the STEREO probes. Maybe with 4 probes launched several months apart so we nearly always have 100% coverage of the Sun.
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Offline Star One

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #15 on: 08/23/2018 07:47 PM »
Common sense would question why you would even come up with a design needing RTGs when you’re going towards the source of all Solar Power. Surely they are only needed when there isn’t enough sunlight for solar panels. Unless you’re trying to fly a design that includes everything plus the kitchen sink so to speak and think budgets are unlimited.
Several of the early concepts had a Jupiter flyby like Ulysses.

That makes more sense. Was to get its orbit even closer to the Sun.

Offline jbenton

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #16 on: 08/23/2018 10:25 PM »
Wonder if there will be a follow-on mission study in the next few decadal surveys?

Something more like the early Solar Probe Plus designs prior to the descoping or something similar to the current PSP design in terms of observation objectives?

If PSP doesn't sufficiently answer the coronal heating questions, or does so while raising a large subset of new questions, then a follow-on might be worth it.

A set of solar probes that could be flown in a constellation to measure the changes in the Sun's magnetic fields, like the Van Allen belt probes do for the Earth, would be extremely facinating.

And I've always wanted to see a follow-on for the STEREO probes. Maybe with 4 probes launched several months apart so we nearly always have 100% coverage of the Sun.

Weren't they planning something like that at one time? The Solar Sentinels mission?

https://web.archive.org/web/20160712142314/http://science.nasa.gov:80/science-news/science-at-nasa/2006/01sep_sentinels/

Offline Blackstar

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #17 on: 08/24/2018 12:38 AM »
If PSP doesn't sufficiently answer the coronal heating questions, or does so while raising a large subset of new questions, then a follow-on might be worth it.

A set of solar probes that could be flown in a constellation to measure the changes in the Sun's magnetic fields, like the Van Allen belt probes do for the Earth, would be extremely facinating.


My understanding is that the interstellar probe mission concept is getting more attention. Solar Probe and IP have always been kinda the two bookend heliophysics missions--go close to the sun and very far away. And both have been limited by technology and cost. This does not mean that IP will get prioritized. And PSP is going to raise new questions that will prompt new missions, but with different goals and parameters. So you may not see something that looks like PSP again, but you may see missions that try to capture related data.

There is also increasing attention to many satellite constellations for solar measurements. Lots of people are excited about cubesats. The problem is that cubesats don't last very long, and if you're going to send them far from Earth you need to worry about things like radiation hardening and longevity. So really it's a constellation of specialized small satellites, not cheapo cubesats as people currently think of them. But taking measurements from many different locations is something that scientists are starting to get interested in.
« Last Edit: 08/24/2018 12:55 AM by Blackstar »

Offline Star One

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #18 on: 08/24/2018 06:37 AM »
Wouldn’t there be a place for another mission to study the Sun by flying over its poles. There has only been the Ulysses mission to study the solar poles so far as I am aware.

Offline Jim

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Re: Parker Solar Probe - post-launch Discussion and Updates
« Reply #19 on: 08/24/2018 01:43 PM »
Wouldn’t there be a place for another mission to study the Sun by flying over its poles. There has only been the Ulysses mission to study the solar poles so far as I am aware.

Solar Orbiter

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