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Parker Solar Probe, Take the Solar Plunge
Explorer1
post Jun 1 2017, 09:50 PM
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Perhaps the heat makes ion engines prohibitive?

Regarding a closer approach at the end, I know they were asked at the press conference why they can't dropped the perihelion even closer, and the reply was that once they're inside the orbit of Venus, they can't make any more rendezvous with Venus.
Presumably Mercury is nowhere near a useful trajectory (being more inclined in its orbit, and much less massive.)
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Decepticon
post Jun 5 2017, 07:38 AM
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Curious will Parker Solar Probe also do Venus Science?

I have found no Information about this google wise.
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nprev
post Jun 5 2017, 05:46 PM
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Here's a link to the instrumentation description. Obviously the mission is real heavy on particle & field observations, and I don't know whether the coronal imager (WISPR) is capable of resolving Venus in any useful way. Still, I'm sure they'll record data of some sort during the gravity assists.

Also, since the spacecraft has officially now been named, this topic has been re-titled. smile.gif


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JRehling
post Jun 6 2017, 09:36 PM
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It took me a while to track down the specs of WISPR… many webpages with vague descriptions of it with links to other webpages with other vague descriptions of it. Finally, I got here:

http://www.affects-fp7.eu/helcats-meeting/...PR_vbothmer.pdf

If I read it correctly, WISPR would not be capable of providing much useful Venus information. It is a "white light" telescope with one wide bandpass of 475-755 nm (blue to near-IR). That is going to show a very blank Venus with none of the interesting wavelengths (UV or thermal IR). The peak resolution is 4.3 arcmin per pixel which is extremely low resolution by the standards of most of the spacecraft imaging missions we think of. Basically, it's a whole sky camera, like what might be used to take a picture of the Milky Way in the Earth's night sky. For Venus to look interesting to this camera, it would have to be zooming right over Venus's day side at close range, and even then it would be pretty much guaranteed to show a colorless blank image.

I don't think in the best of circumstances WISPR could do any original Venus science.
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scalbers
post Jun 6 2017, 11:59 PM
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I wonder if some high-phase angle images with such a camera at fairly close range could show some interesting atmospheric effects. Even the ashen-light if it were to exist. Possibly in the daytime I wonder if there are some subtle colors, either brownish if sulfuric acid absorbs or bluish as Rayleigh scattering contributes along with the clouds.


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JRehling
post Jun 8 2017, 12:41 AM
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WISPR wouldn't see color – by "white light" the specs mean a single plane responsive to one wide range of wavelengths, in layman's terms, a black-and-white camera.

The only conceivable advantage over existing datasets would be if it captured Venus' phase angle function from a unique perspective, but Earth-based observations provide basically all angles except the perfectly "full" and perfectly "new" Venus, and we know that Venus Express has covered the "full" phase and multiple orbiters have had the opportunity to image Venus' night side. So I can't see any science coming from this if we're talking about persistent appearance of the planet. Of course, we can never rule out something sporadic light imaging a lightning flash on the night side, although WISPR's quick passes will provide far less chance of that than the long missions of, e.g., Venus Express and Akatsuki.
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Explorer1
post Jul 26 2018, 03:51 PM
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The launch has been delayed a few times to August 11th; is the first Venus flyby 'locked in' for September 30th because of orbital mechanics? If so, then at six weeks this is probably the fastest launch to Venus encounter (or any planet!) in history!
Mariner 2 was 110 days travel time, Venera 3 we're not certain because of the communications failure, put maybe less. Anyone know for certain?
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Holder of the Tw...
post Jul 26 2018, 07:08 PM
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The time from launch to probe entry for Venera 3 could have been either 105 or 106 days (105 is listed on the Wikipedia article, my date calculation is 106 not taking hours and minutes into account).

Regardless of the launch date, I would expect Parker to arrive at Venus on or near September 30th. Recent Mars probes launched late had pretty close to the same arrival dates. There might be a couple days difference.

More important, they are starting to run out of time. As explained in this article which was issued for the Aug 6th launch date, they only have until August 19th (or maybe August 23rd at the very latest) to get it off before spending a lot more time and money waiting. And I will guarantee you a different Venus fly by date if that happens.

EDIT I believe the current holder of the record for Earth to Venus is Mariner 10, which made the trip in 95 days. Also, I neglected to notice that this launch differs from the Mars shots I mention due to being a high energy trajectory. So the effect on the arrival date might be more significant, but I don't know by how much.
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Holder of the Tw...
post Aug 1 2018, 01:43 PM
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Latest news is that the Venus flyby will be October 2 based on an August 11 launch. So about 53 days to first encounter from departure.

Spaceflight Now article

"... Driesman told Spaceflight Now he is confident the mission will get off the ground in August.

'The operations are proceeding at what I would call a normal pace,' he said. 'There’s always time built in for not getting things right. At this point, we’re on track for the 11th (of August) launch date.'"
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JRehling
post Aug 1 2018, 05:18 PM
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Mariner 10 reached Venus in 94 days. I don't know if that's the record, but I thought it would be worth checking since the whole point of the encounter was for a gravity assist on such a high-delta-v mission.
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Paolo
post Aug 1 2018, 05:40 PM
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Cassini Venus to Earth in 1999 was 55 days
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Holder of the Tw...
post Aug 8 2018, 01:57 PM
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QUOTE (Bob Shaw @ Dec 28 2005, 06:05 AM) *
You're all missing the obvious way to design a Solar Probe, although ISA already described a most persuasive mission scenario.

Just build one and launch it at night!


Hey, they ARE launching it at night! So NASA must be thinking the same thing.

You can never be too careful. wink.gif
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Keatah
post Aug 8 2018, 06:19 PM
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Well at least they are launching it at night! For real.Attached Image
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nprev
post Aug 11 2018, 04:07 AM
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Launch now set for 0753 GMT. Live coverage here.

Note: For those who have never seen a Delta IV Heavy launch before, the exteriors of the three booster cores tend to...er...catch on fire during initial ascent off the pad. This is caused by entrapped vented hydrogen that is subsequently ignited by the engines, and is both normal and expected. Since this will be a night launch, the effect should be rather spectacular. smile.gif


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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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nprev
post Aug 11 2018, 07:42 AM
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T minus 10 min now. So far so good.

GO PARKER!!!!!!!!!

EDIT: No-go for unspecified condition, waiting for new T-0.

EDIT2: New T-0 0828 GMT.

EDIT3: ....aaaaand, scrub.


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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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