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I have just received the author's copies of the March issue of the JBIS, with my article on the history of two 1970s European deep space missions, including the first close perihelion Sun probe study
NASA Calls on APL to Send a Probe to the Sun

It seems they plan to use deployable solar arrays (however, the mission home page still states that there will be MMRTGs)
Nasa Plans to go to the Sun

Seems its becoming a reality.
More detailed technical information here:
Solar Probe+ Mission Engineering Study Report
Solar Probe Plus has been given the green light to move into Phase A. Basically, it's a real mission now. Launch is scheduled for 2018 currently, but that's due to budgetary restrictions, not technical ones. According to the APL managers, this mission could go 2-3 years earlier if additional funding was provided.
The launch date on this website is incorrect.
It seems that the ESA Solar Orbiter mission (if selected) would compliment Solar Probe+, and possibly even launch on the same vehicle. ESA's mission won't get as close to the Sun, but having two spacecraft at different radii would allow some synergistic science.

We can never have too many solar missions smile.gif smile.gif
A new article on Solar Probe Plus... 5 science instruments have been selected for the mission

So will NASA or The Planetary Society have a "Send Your Name to the Sun" campaign before the launch in 2018? biggrin.gif
Actually only four instruments mentioned, but radio science isn't mentioned, so that might as well be a 5th.
QUOTE (Geographer @ Nov 8 2007, 05:18 PM) *
What is the highest level of albedo that's been achieved with metals on Earth? If a shield had 100% reflectivity (impossible I know but theoretically), would that solve all heating problems, or does the albedo vary for different types of electromagnetic radiation?

At least in visible light silver is pretty high (somewhere above 90%). Dielectric coatings can use interference to make reflectivity even higher. More info here on reflectivity of coatings:

What is being used on the shield in the solar probe design?
QUOTE (scalbers @ Sep 19 2010, 04:57 PM) *
What is being used on the shield in the solar probe design?

I was determined to find the answer to this seemingly simple question.

Judging from the document, they're hedging their bets for prototype build and testing, but it will likely be 15cm of carbon-carbon with a coating of aluminum oxide or pyrolytic boron nitride.

Page 58/146 marked as 3-42 of this:
As part of the TPS Risk Mitigation effort, two potential ceramic coatings were found that met the requirements of the Solar Probe+ mission. Ceramic materials that are visibly white generally provide the optical characteristics compatible with the proposed shield passive thermal management strategy. These characteristics are low solar absorptivity and high IR emissivity. Thermodynamic stability and chemical compatibility with C-C are additional differentiators that further narrow the list of candidate ceramics. At the end of the study, both aluminum oxide (Al2O3), commonly called alumina, and pyrolytic boron nitride (PBN) were found to notionally satisfy these basic characteristics.

Plenty more in there.
QUOTE (tedstryk @ Jul 19 2007, 01:41 PM) *
If it actually gets funded, it should also give us a nice Jupiter bonus.

In reading about the thermal shield, I've just noticed the new mission has a perihelion that is farther than the original plan, and incidentally an aphelion at 1 AU. So no Jupiter flyby. They dumped the RTGs that would've provided power out there as well.

A good point mentioned in the report is that by lowering the perihelion gradually with aphelion TCMs, they have time to learn to manage the spacecraft before getting closer. Jupiter would no doubt have sent it right in.
QUOTE (stevesliva @ Sep 2 2010, 08:45 PM) *
Actually only four instruments mentioned, but radio science isn't mentioned, so that might as well be a 5th.

The linked article mentions five instruments; the ISIS investigation uses two instruments, EPI-hi and EPI-lo, presumably to measure particles at different energies. It also discusses five investigations that have been funded, the fifth one being a project scientist that won't fly with the spacecraft. Obviously.
More on one of the instruments

Wide-field Imager Selected for Solar Probe Plus Mission
Solar Orbiter is selected as ESA's first M-class mission:
Europe to lead daring Sun mission
selected again, you mean. I don't want to get into politics, but Solar Orbiter has been on and off several times at ESA and was first selected as a medium mission in the early 2000s...
Solar Probe Plus mentioned in this interesting solar wind article:

Also mentioned is WIND, still trucking after almost 19 years...
ESA's Solar Orbiter has recently been delayed from January to July 2017. On the other hand, I have not been able to find the sequence of flybys for the July 2017 launch. Ideas anyone?
Whatever happened to this sun-grazing spacecraft concept ? ....anybody here know ?

Click to view attachment
it's now known as the Solar Probe Plus, an approved (and funded!) NASA-APL mission for launch in 2018.
Holy 2001-Space-Odyssey-caveman-thrown-bone-turning-into-spacecraft moment!

"A pigment once daubed on cave walls by prehistoric Man will help shield [ESA Solar Orbiter] an unmanned probe that will fly close to the Sun..."
There is a user of the Orbiter Spaceflight simulator currenly working on simulating both the Solar Probe (+) and the 2005 version, the preliminary models are depicted flying by Venus:

and Jupiter:

QUOTE (Paolo @ Dec 3 2013, 08:33 PM) *
ESA's Solar Orbiter has recently been delayed from January to July 2017. On the other hand, I have not been able to find the sequence of flybys for the July 2017 launch. Ideas anyone?

It has just been delayed from Jul 2017 to Oct 2018. The decision to postpone the launch was taken in order to ensure that all of the spacecraft’s scientific goals will be achieved, with all the system’s components adequately tested prior to sending the spacecraft to the launch site.

According to this paper (it refers to a Sep 2018 launch window, however I think it will be the same for Oct 2018):

The transfer phase for this mission profile begins with a launch in September 2018, with an escape velocity from the Earth of 3.66 km/s and declination of the escape velocity of –41.5°. About 5 months after launch, a Venus GAM with a pericentre height of more than 11000 km places the spacecraft in a trajectory towards the Earth. An Earth GAM 10 months later puts the spacecraft into an orbit such that another Earth GAM occurs 22 months later. 2 months after the last Earth swing-by the spacecraft arrives at Venus with a hyperbolic velocity of 19.3 km/s. A sequence of resonances 1:1-1:1-4:3-3:2-3:2 is then performed at Venus during the science phase such that the solar inclination is gradually raised up to the final maximum value of 34°. The design of this sequence of resonances has been driven by the minimization of the maximum length of communications interruption due to safe mode during solar conjunctions. A first 4:3 resonance like in the January 2017 mission profile, while more attractive in terms of science, would exceed the limit of the current spacecraft design. The perihelion distance therefore rises slightly during the two 1:1 resonant orbits and drops below 0.3 AU for the 4:3 and the first 3:2 resonant orbits. The first perihelion within this distance occurs 4.6 years after launch. The maximum solar latitude is reached 7.6 years after launch. The characteristics of the September 2018 mission profile are summarized in Table 4.
New announcement tomorrow on Solar Probe Plus:
Looking over the details of this mission, and contemplating the current mission finale for Cassini, I'm left wondering about the mission finale for the Parker Solar Probe. Perhaps a final orbit aimed at skimming the solar surface, and transmitting data until the vehicle dies? In the interim, perhaps crank-up the inclination during mission extension so that we get some polar views of the sun like we're getting from Jupiter by the Juno probe?

Yes, I know, it is still way to early to worry about this sort of thing smile.gif

Oh, and why no ion propulsion? I would have thought this would be the ideal mission for that, in terms of solar power. But it seems to do okay with Venus slingshots.
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.)
Curious will Parker Solar Probe also do Venus Science?

I have found no Information about this google wise.
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
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:

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.
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.
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.
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?
Holder of the Two Leashes
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.
Holder of the Two Leashes
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.'"
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.
Cassini Venus to Earth in 1999 was 55 days
Holder of the Two Leashes
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
Well at least they are launching it at night! For real.Click to view attachment
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 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
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.
I believe New Horizons took about 9 hours, from launch, to cross the Moon's orbit, giving it the fastest Earth departure ever.
I suspect Parker may have exceeded that, but can't find the relevant facts -- any ideas?

I was looking for the trajectory views using NASA's Solar System Simulator, seen here for New Horizons :

Where is New Horizons?

But the same thing does not (yet) seem to be up for Parker.
According to Jonathan McDowell, it was a lot faster (see this tweet: .)

And there's this:

Holder of the Two Leashes
A very detailed update on Parker:

Early milestones accomplished
first images from the wide field camera:
Illuminating First Light Data from Parker Solar Probe
Bit surprised at the quality of these since I thought all the cams were designed for far higher light levels. Pleasantly so, though. smile.gif
WISPR looks for plasma coming off the Sun, so it's not too surprising it's a decent dark-sky camera.

Maybe it'll get really lucky and find some Vulcan asteroids! Looks like STEREO searches have removed chances of anything larger than ~6km.
QUOTE (hendric @ Sep 20 2018, 09:56 AM) *
Maybe it'll get really lucky and find some Vulcan asteroids! Looks like STEREO searches have removed chances of anything larger than ~6km.

Remember that if one considers the length of the mission, we might get a sungrazer comet near perihelion. The unique angle of observation (and distance) would provide valuable science when combined with observations at 1 AU.
Though there's no dust sensor onboard, so no direct way to see if it passes through any of their debris streams?
Maybe dust impacts could be detected via attitude control.
Venus Flyby Complete!
Steve G
That's crazy fast. What was the next quickest launch to planetary flyby?
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