Dawn is now attached to its third stage kick motor:

http://mediaarchive.ksc.nasa.gov/search.cf...rch.cfm?cat=173

2 weeks from Saturday...

Agree that these look like the old Pioneer images of the Galilean moons...

I think Ceres will be much more "processed" than Phoebe... but not active like Triton. Ceres be the first dwarf planet to be visited..... if you do not include major moons.... and if you disqualify Vesta due to not being "sherical" in shape... but that may just be due to a major impact event... and NO, am not trying to open up that debate here in this thread.

DAWN should reach Ceres before New Horizons reaches Pluto/Charon. Will really be interesting to compare these two dwarf planets since the data for both should be reaching Earth in the same year, 2015.
An inner snowline dwarf and a Kuiper dwarf..... wonderful

Triton
http://photojournal.jpl.nasa.gov/jpeg/PIA02212.jpg

Ceres
http://i14.tinypic.com/4l78uwm.jpg

Phoebe
http://photojournal.jpl.nasa.gov/jpeg/PIA02229.jpg

WOW.. my Grandsons will be 9 years old then.... I better start prepping them now!!!!!


Craig

Will Dawn orbit Earth before heading to Vesta?

No.

It will immediately be in an Earth escape trajectory like every other interplanetary mission

Well, technically not true, PB; remember Galileo & Magellan were Shuttle-launched. True within the context of unmanned boosters AFAIK, though.

A pity in a way. Launch windows would be much broader if planetary missions could be parked in LEO before departure, though of course that completely defeats the purpose of the booster's initial and inherent delta-V capabilities.

I still am new to this and cannot "quote"

"Will DAWN orbit Earth before heading to Vesta?"

I doubt any other planetary spacecraft will ever spend much time in Earth Orbit after that CONTOUR debacle.

Article about Dawn mission from 2004 (pdf)
http://www.astro.umd.edu/~hamilton/teachin...06/mcfadden.pdf

Dang! How many guys in bunny suits does it take to screw in a spacecraft?
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=32551

Depends on how "direct ascent" is defined. Even NH was in a parking orbit, though only for about 30 minutes if I recall correctly. So while it did not make a complete orbit around the planet, it nevertheless was in a temporary orbit. And if I recall correctly again, NH was originally going to launch at night for a direct ascent trajectory.

One definition of direct ascent is a trajectory in which the upper stages make a back-to-back continuous burns all the way to earth escape velocity without any coast phase. NH's Centaur state made an initial burn, then coasted for about 30 minutes, then a 2nd burn to put the NH and the Star-48 kick stage into escape trajectory. If the 2nd burn were not done, NH would be stuck in Earth orbit. [edit] Actually, if the 2nd burn does not occur at all, I guess NH would hit the top of the atmosphere on its next perigee. It may make it around once or a few times, but it's going to reenter pretty within a few orbits if any.

As nprev noted, parking orbits allow for a little more flexibility in the launch window. Another reason for parking orbit is to position ground stations under the critical Earth escape staging and spacecraft deployment sequences. A direct ascent trajectory may not put ground stations in the right place at the right time.

I have not seen the launch event timeline for Dawn, so I don't know if it uses a direct ascent (as defined above) or not. If the Dawn Delta 2nd stage does two burns with a coast phase between, then I would not call it a direct ascent.

The second stage will make two burns.

Analyst

The pedantic in me would suggest that I orbited Earth when I jumped out of my seat at those Hubble images. Granted, it wasn't much of an orbit, but still...

http://www.nasa.gov/mission_pages/hubble/news/vesta.html

Yea, I think New Horizons would be ROYALLY screwed over if it spent 6 hours in LEO like Magellan and Galileo did onboard the shuttle. Well... Not really. If the payload bay was big enough to fit a third stage PLUS the Inertial Upper Stage, NH would probably be fine.



After that incident with the solar panel? You need a lot

The payload bay can. Ulysses had a IUS with a Star 48 in the shuttle.

"The pedantic in me would suggest that I orbited Earth when I jumped out of my seat..."

Very very low perigee.

You're "in orbit" if your perigee is above something a bit below 80 miles. Early Mercury missions orbited at about 90 miles. They were "good for a few orbits"

Minimum orbital altitude is where a bowling ball in a circular orbit can just barely make it once around before entering.

NASA Teleconference to Replace Televised Dawn Mission Briefing
MEDIA ADVISORY: M07-72
June 25, 2007

Uh oh. Note the passage: "Mission managers will discuss several issues that need to be resolved before Dawn's July 7-11 launch window."

Woops. And note the change in personnel. No Dawn folks, only HQ people. This does not sound good.

--Emily

Yeah, it doesn't look like "all systems go" when NASA HQ "hubcaps" (and no, I don't include Alan Stern in this category) are last minute replacements for members of the team, and via telecon, at that.

Why not? he is no different. They are just his underlings

IMO, Alan is too new to Washington to be considered captured by Inside-the-Beltway Pod People. However, if in a few months he starts trying to convince people the moon is made of green cheese because such a view is "consistent with Administration priorities" or is "sensitive to congressional concerns," then I'll have to re-evaluate.

"consistent with...." and "sensitive to bla blah concerns" -- these phrases make my skin crawl!

Greeaaat. Is this yet another situation where it wouldn't be a surprise if Phoenix (or Endeavour on STS-118) leave Florida first? Or am I just jumping the gun here?

If Dawn does not launch before Phoenix, the drop dead date will be Oct 2007 after which a trajectory to rendezvous with both Vesta and Ceres will not be possible with the current propulsion constraints.

This really does not sound good. But the launch window is long, so no need to worry yet.

Maybe cork is falling of the Delta rocket, or a fuse just fired? I am kidding.

Analyst

Sorry, my bad. I had misspelled my name on the chip and they have to replace it.

Am I the only one who thinks "Dawn" has been an overly optimistic name for this mission? The poetic implications of "Dawn has been cancelled" or "NASA says that Dawn will be postponed" always sound so bleak to me.

I hope my morning paper's
front page story is a good omen.

(Nothing topical in the story,
just an overview of the mission.)
Click to view attachment

Considering the kind of trivial nonsense that delayed Dawn from June 20 to its current launch date... I wouldn't be surprised if any of that happened.

Hey, Ben! Are you one of the photographers in this photo?
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=32559

--Emily

Do you know the reason for the delay from June 20 to June 30? Delta stacking problems caused the delay from June 30 to July 7. But what has been the reason for the first delay?

Analyst

Ben's the one in the white overalls

Doug

Check out the latest blog entry from Marc Rayman.

Blog seems 'nominal' - bar the Solar Array ding we already knew about.

Doug

The launch press kit is now online (2.13 Mb PDF).

EDIT: Maybe it's me, but for some reason the kit doesn't look complete. Perhaps it's still in draft form.

http://dawn.jpl.nasa.gov/mission/status.asp

What the hell are they going on about?

They have 'issues' that are no different to any previous mission....so they cancelled the science briefing.

This is the most evasive, vague, non-specific briefing I've ever heard. They've known about the launch window for several months - and now they're saying they're proceeding full steam ahead for a July 7th launch - but that they have 'late breaking' issues regarding the forward attach points for the GEM's but they're already on track on that issue and a down-range comms issue for which they already have a workaround.

I'm kind of wondering where the beef is.


Doug
(PS - a significant telecon on Thursday for Opportunity going into Victoria - I assume the NASA HQ 'OK' to go in)

Yeah, it was all a bit confusing. I think maybe they wanted to delay the science press conference until they made the final decision on Tuesday, but then they were left with having to tell the press something, so that's what happened today.

--Emily

It seemed like they were trying to say that they didn't want to trouble the science team while they were still figuring out these issues - but the issues they mentioned (LV analysis and Range ) have nothing to do with the science team.

They've got a couple of weeks to get Dawn away - surely more than enough to clear these two issues - why they felt the need to mention the $20m+ that would be involved in delaying through till september requiring a new second stage I just don't know.

Doug

Naw, the New Horizons press kit looks the same



1 week, 4 days to be exact...though what's this about a new second stage being needed?

Actually they only have from July 7-11, and an afternoon launch, with pesky weather. That's an awful short window.

--Emily

Ahhh - ok - that puts a bit more pressure on - they need to be 100% sure they're good to go at the start of the window...but - why does it close on the 11th when the absolute window closes in October. A couple of days to reconfig the range for Phoenix - but what's happening at the end of the July to mean the windows closed.

Doug

What's missing is the typical pre-launch press release that usually precedes the detailed mission section. However, given that today wasn't a normal pre-launch "press conference" (i.e., NASA SMD AA, mission PI, other science teams members, etc.), then this isn't too surprising.

Strange briefing. Why does the window end on July 11? They could have launched the MERs 10 day apart, this would give us a window until July 24. Isn't this a ULA problem, they caused all delays from June 20.

Analyst

I'm not sure about the launch period (i.e., whether it's continuous until September) but the July 11 cutoff has a lot to do with range availability and launch vehicle extended duration on the pad.

EDIT: deleted some speculation that didn't seem worth preserving in light of later comments.

Big thanks to Alex for posting the link to the press conference audio feed.

TTT

Are you sure Alex? The LV has been on the pad for not very long, stacking was actually running late. And there are no other launches in July from CCAFS.

Analyst

I'm trying to be elliptical, and it looks like I succeeded.

Fuel is very corrosive, no?

The planetary window closes July 19 and reopens Sept 7 or so.

The launch period closes July 11 as dictated because of a couple of reasons; one is that they need time to clean up the pad before bringing Phoenix out. The other reason is that you cannot conduct a launch with a spacecraft on the other launch pad. If it launches July 12 they say they won't have enough time to get ready for Phoenix to meet August 3. In addition if it can't launch they need time to remove Dawn from its rocket.

If they decide to launch Dawn July 7, it has 45 days to launch from there onward; the second stage has a short lifespan once it is fueled. They cannot get a new second stage until October or so; so if they decide to launch and Dawn isn't off the ground by July 11 they may be in trouble.

They also stated that if they decided to delay at this time and not press ahead next week, it would cost $25 million or so.

I believe I covered it close to accurately here.

Thanks, Ben. I was hoping you'd jump in.

And thanks for clearing up the launch period issue; the discontinuous aspect was new to me.

You see - NOW it makes sense. The start of the window getting pushed right because of a couple of issues has meant that they're pushed to get it away before the cutoff at which point they'd have to destack to make way for Phoenix - and because the 2nd stage is a right off once fuelled, it would have to be replaced if they had to make way for Phoenix

Now - why couldn't they say that in the press con. Get out from behind the lens and get a job with KSC PAO Ben.

Doug