I posted a few days ago that NASA’s MESSENGER probe is headed toward a rendezvus with Mercury on Monday. In the comments, BigBob noted that the first image has been returned!
This was taken on January 11, when the spacecraft was still 1.7 million kilometers from the planet. On Monday, it will pass about 200 km over the surface (yikes!). It will fly on, making two more passes of Mercury over time before settling into orbit, and making a detailed map of this planet. That’ll be in 2011, so the images we see from this first of three flybys will have to do you for now.
January 12th, 2008 at 2:44 pm
Holy Crap! Just 200km above the surface! That’s lower than the ISS above the earth as far as I know. Good that mercury has got no atmosphere. I guess we will get very interesting pictures after monday!
January 12th, 2008 at 3:34 pm
Wow, thanks. Can’t wait to see the 200 km shots!
January 12th, 2008 at 3:41 pm
That 200 km figure assumes that NASA doesn’t screw up its English to metric conversion again….
January 12th, 2008 at 4:55 pm
200km? That’s nothing! In March 2008 Cassini will be passing Jupiter’s moon Enceladus nearly 10 times as close — a mere 23km from the moon’s surface!
Seriously, though, considering the distances and speeds involved, it is truly amazing what they can do in space navigation these days.
January 12th, 2008 at 5:08 pm
This is gonna be so cool.
Question.
In between the first pass and settling into orbit, does the probe make consecutive smaller orbits or does it actually take off and reconnect with the region (given the small orbiting time of mercury) again. I.E., where does it go in between the three passes and settling into orbit?
January 12th, 2008 at 5:15 pm
It will be a beautiful thing to see. I eagerly await MESSENGER’S pictures.
January 12th, 2008 at 5:46 pm
Never have I felt excitement for the Iron Planet as I do now.
Go Messenger!
BTW, Tacitus, I think you mean “Saturn’s moon”.
Cassini hasn’t been at Jupiter since 2001. Hmm, wonder if any monoliths were spotted…….
January 12th, 2008 at 5:56 pm
Ulp – yes, of course, Saturn (doh!).
Jeffersonian — this page has an animation of Messenger’s tortuous route into orbit around Mercury:
http://www.planetary.org/news/2008/0110_MESSENGER_Set_for_First_Spacecraft.html
As you can see, it’s basically still going to be orbiting the Sun (not Mercury) for quite some time before it can enter any sort of orbit around the planet.
January 12th, 2008 at 5:56 pm
from 1.7 down to 200km in +/- 40some hours- wow, that thing is moving!
I’m still fuzzy on how the gravity assist slow down thing works for eventual insertion.
January 13th, 2008 at 12:15 am
Solar System Spirograph!
Seriously, how great is math that we sacs of fluids, minerals, and fats can shoot little things into insanely complex orbital trajectories, and have it work out just right, so a bit of our little orb is able to interact with a (relatively) nearby littler orb, and know in advance what is going to happen.
I’m glad that I’m sentient.
January 13th, 2008 at 5:08 am
Actually, Mercury does have an atmosphere, but it’s an extremely tenous one (about 10-12 bar, if I remember correctly).
January 13th, 2008 at 9:44 am
BPL: 10-12 bar is not tenuous. Earth’s surface atmospheric pressure is about 1 bar. Even 10-12 millibar is denser than Mars’ atmosphere which about 7 millibar. Guessing wildly, do you mean pascals?
January 13th, 2008 at 2:44 pm
[...] via Bad Astronomy Blog [...]
January 13th, 2008 at 11:57 pm
Vrery minorest of microscopic nitpicks but I think the word ‘rendezvous’ needs coorecting …
Sorry I’m shocking with typos myself I know – so meaning to be helpful.
Great news, small image of a small planet – I’m looking forward to seeing the details and finding out if Mercury really may have the largest volcano in the solar system as some have suggested based on RADAR data …
January 14th, 2008 at 12:04 am
well I did say I’m shocking when it comes to having typos myself … But I didn’t realise or intend to prove it with that first sentence there :
“Vrery minorest of microscopic nitpicks but I think the word ‘rendezvous’ needs coorecting … ”
= Very minorest of microscopic nitpicks but I think the word ‘rendezvous’ needs correcting …
January 14th, 2008 at 6:01 am
Ed Davies writes:
[[BPL: 10-12 bar is not tenuous. Earth’s surface atmospheric pressure is about 1 bar. Even 10-12 millibar is denser than Mars’ atmosphere which about 7 millibar. Guessing wildly, do you mean pascals?]]
Typo on my part. I meant to write 10 to the -12th power bars. Either I got the superscript tags wrong, or forgot them altogether, or this site won’t show them.
I’ll try down here:
10-12
January 14th, 2008 at 6:02 am
No, looks like the BA web site software won’t display superscript tags properly. I know it does italics, but maybe it’s only got the most basic HTML 1.0 set — underline, italics, bold. Undoubtedly subscript tags won’t work either. Let me try: CO2.
January 14th, 2008 at 12:50 pm
[...] Messenger takes aim at Mercury (Bad Astronomy) [...]
January 14th, 2008 at 1:35 pm
Ah, yes, 10 to the minus 12 bar makes sense. Tenuous as you say.
As a similar experiment, here’s a form using Unicode superscript characters: 10?¹². Let’s see how that comes out.
January 14th, 2008 at 1:40 pm
Ah, yes, 10 to the minus 12 bar makes sense. Tenuous as you say.
As a similar experiment I tried typing the value using Unicode superscript characters but got a database error: “WordPress database error: [Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '=']“. Pathetic.
January 14th, 2008 at 3:02 pm
Oh, so the first of those two messages did get posted, but with a question mark instead of the superscript minus.
1e-12 bar is, unless I’m out by a factor of 1000 or something, 100 nPa (nano pascals). To put that in context, the pressure of the solar wind in the region of the Earth can be around 1 nPa or more (http://www.swpc.noaa.gov/SWN/index.html). The solar wind must be nearly up to local atmospheric pressure at Mercury. That’d make for an interesting shape to the atmosphere, I’d have thought.
January 15th, 2008 at 6:00 am
Ed Davies posts:
[[1e-12 bar is, unless I’m out by a factor of 1000 or something, 100 nPa (nano pascals). To put that in context, the pressure of the solar wind in the region of the Earth can be around 1 nPa or more (http://www.swpc.noaa.gov/SWN/index.html). The solar wind must be nearly up to local atmospheric pressure at Mercury. That’d make for an interesting shape to the atmosphere, I’d have thought.]]
Good point! I’d love to see a simulation — if they did it in color and 3D it would make for an interesting BA article photo…