An overlooked mission yet one that will be the focus of media attention in 155 days from now on July 4 2005, so there's time left to post a message before impact

cIc

Does annyone know if DI has any plans after primary mission?

Waste of a probe if its not used for anything else.

Good question. After data playback DI will be a fully functioning spacecraft with nowhere to go. It has two telescopes (30cm and 12cms diameter) a multispectral camera and an infrared spectrometer. There should also be some of the original 86kg of fuel left after trajectory corrections.

There is an undefined period between EOM and EOP where something may happen such as navigation tests. Retargeting to another object followed by hibernation may be possible.

There is very little or no money as, according to this story the project has overspent (from $279M to $313M) and been descoped (one year earth orbit test phase cancelled) so an extended mission will need more funding.

Impact: 4 July 2005
End of Mission: 3 August 2005
End of Project: April 2006

http://www.nasa.gov/deepimpact
http://deepimpact.umd.edu/
http://deepimpact.jpl.nasa.gov/

152 days to impact

I have heard talk about trying to send it to at least one more comet. If funded and if it has enough fuel, maybe it will be able to somewhat make up for Contour.

I'm sure it'll get that funding - a pre launch press conf mentioned that they have several follow-on candidate targets.

Of course - the spacecraft may get damanged during the flypast, who knows.

I think they're planning to use Genesis for training, and to measure some solar wind features as well - if nothing else, DI could be used for that.

DI will only be 6 months old when it's primary mission is over. For most spacecraft, they've barely finished checkout and have 8 years ahead of them at that stage

Doug

Lets hope DI has 8 years to explore many comets!

Looks like great news!

Thanks for the updates.

I wonder if DI's done any Earht Observations as a calibration exercise as it was leaving
?

Doug

I remember reading it would. But whether it will be Mariner 10 quality or Rosetta quality or somewhere inbetween is unkown.

Deep Impact went into safe mode shortly after launch, so that means no science observations.

They recovered from that safing very quickly - and I would have thought some calib.type stuff would have been maybe 5, 10 days out ( a couple of lunar distances ) and would have been unaffeected.

Doug

There is a neat DI simulator available at http://neo.jpl.nasa.gov/orbits/deepimpact.html
(requires Java) that will trace the trajectory all the way through to impact on July 4 2005.

The simulator will also run forward until 14 February 2008 and show close encounters between DI and both Mars and Earth. It's not clear if these encounters are based on the trajectory changes that will be made just before encountering Tempel 1. The simulator does warn that it uses 2 body methods and is not accurate over longer timescales.

Further to Decepticon's question about plans after encounter, in the second to last paragraph on that page it says:

"If the spacecraft is healthy and if NASA is able to grant the necessary permission and resources, the spacecraft could then be re-targeted for another cometary flyby by using the Earth encounter to re-shape the spacecraft's trajectory."

There is also a project outreach page about observing Tempel 1 and the impact here: http://deepimpact.umd.edu/amateur/index.shtml

146 days to impact

1st trajectory correction maneuver (TCM) performed successfully on 11 February 2005.

Coming up: scientific calibrations, an encounter demonstration test, ground operational readiness checks and a second TCM.

http://www.nasa.gov/mission_pages/deepimpact/main/index.html


141 days to impact

(1) The DI people have been considering a follow-up comet flyby almost from the start, and two possible targets have been identified. One is Comet Finlay, but I don't know what the other one is.

(2) DI did indeed take some calibration photos of the Moon shortly after leaving Earth, and one has been released. It looks -- unlike the fuzzy misted-up Stardust photos -- nice and clear.

Here it is:



119 days until impact.

Thanks for the image ObsessedWithWorlds, it's good to see proof that the camera works

Deep Impact have the image on their site now with a caption that i'll paste here to save clicking.

"Four days after launch from Cape Canaveral on January 12, 2005, the Deep Impact spacecraft pointed at the Moon to test its telescopes, cameras and spectrometer. This image was taken on January 16, 2005, with the Medium Resolution Imager (MRI). It was a 9.5 sec exposure. The spacecraft was more than 1.65 million kilometers (1.02 million miles) from the Moon, and a little more than 1.27 million kilometers (789,000 miles) from Earth. The spacecraft is scheduled to impact comet Tempel 1 on July 4, 2005."

http://www.nasa.gov/mission_pages/deepimpa...mpact-moon.html

Only 100 days to impact and still no update from the Deep Impact team, hopefully no news means good news.

Here is another site to browse while waiting for the encounter to begin: spacetoday

I got an email from the Deep Impact website:

DEEP NEWS
Newsletter for the Deep Impact mission
Issue #20, March 2005


The Deep Impact twin spacecraft is entering its third month in space. The project team is hard at work implementing their carefully planned mission. The spacecraft launched on January 12th from Cape Canaveral and is on its way to its July 4th impact with Tempel 1. What's been happening with Deep Impact? Read below to find out. If you aren't familiar with the Deep Impact mission, take a look at:
http://deepimpact.jpl.nasa.gov
http://deepimpact.umd.edu

Image of Moon/Jupiter:

http://deepimpact.umd.edu/gallery/commissioning.html

From Deep Impact Mission Status 03.25.05

the good news:

"NASA's Deep Impact spacecraft has completed the commissioning phase of the mission and has moved into the cruise phase."

the not so good news:

"At completion of the bake-out procedure, test images were taken through the High Resolution Instrument. These images indicate the telescope has not reached perfect focus."

Oh dear, Hubble disease again

Hope it's not too bad...

It's not uncommon for things like this to happen. Cassini had a similar problem that got solved by extra bakeout cycles. So we'll just have to wait and see what happens.

The image of Jupiter taken with the HRI looked unsharp - I think it must be sometimes sharper and is described as "not reached focus" at the Deep Impact homepage.

Robert

http://aviationnow.ecnext.com/free-scripts...rticle=04045p04

Here is the latest. Looks bad.

You can say that !

I can't find out if they're planning more backing out cycles or not. Seems to me they're telling us however, that it doesn't have to do so much with the moist itself (in blurring the image), but with it's influence on the focal length (and dimensions of the scope-tube).

I don't like to say these kind of things, but it doesn't make sense to me that they "forgot" to implement an extra (secondairy) focussing device in the imager. I just don't get it. It is SO important to have a crisp view of what's happening in these seconds, that they should have put more effort in making sure it can be callibrated in more than 1 way !

There goes the extended mission....

I'm looking into this matter myself -- I suspect that, given the cost problems with recent Discovery missions (including this one), they simply could not afford such a secondary focusing system. After all, they haven't had one on other cameras on planetary spacecraft, and were presumably gambling that it would not be necessary this time -- although this is by far the most powerful optical system ever put on a planetary spacecraft. As for how much ground-based deconvolution can compensate for the problem: I'm hearing conflicting accounts.

But at any rate this may be a further consequence of the crisis that the Discovery Program has now encountered, and which forced them to completely cancel their last mission selection -- namely, that the current cost cap for scientifically worthwhile Discovery missions has simply become too low and must be raised, at the expense of flying the missions less frequently than was previously the case. As was pointed out recently, given the cost rise in launch vehicles and the less general inflation rate, the Messenger mission -- which was initialy accepted beneath a $300 million cost cap -- would take $430 million to fly today. And the current cap is only $350 million, so obviously something has to give. The new Discovery mission selection round -- which will be initiated this month -- will have a raised cap.

We are now running out of Solar System missions that can be so cheap and yet make significant new scientific discoveries at this point. By insisting on flying one new Discovery mission per year, we have been flying them at a faster rate than the rate at which new technical innovations can cut their cost back down. And one conclusion of NASA's new Solar System Strategic Roadmap Committee is that, in another decade, the same thing will start happening to the the medium-cost New Frontiers missions as well.

edit: oops nothing to read here now, i see sunspot has already posted this story elsewhere.

http://www.planetary.org/news/2005/deep_im...mpel1_0427.html

Deep Impact's First Glimpse of Its Destiny

Two months away from its rendezvous with a comet, Deep Impact has caught its first glimpse of its target. Comet Tempel 1 was 63.9 million kilometers (39.7 million miles) away from the spacecraft when it captured the snapshot at right.

Nasa Mission News

now just 68 days to impact

"Too Cheap" can compromize you till you fail to achieve the primary mission goals. I'm afraid, despite the spectacular degree of the NEAR Eros orbiter mission's success, including it's "obviously impossible" landing on the asteroid, many scientists feel the mission failed to achieve it's primary mission objective: Proving that S Type Asteroids are or are-not the parent bodies of chondritic meteorites.

The camera was small, with frame dimensions since Mariner 4, with non-square pixels, and a good deal of perioduc and random noise clearly visible in 8-bit versions of the images. After the attutude upsed during the "anomaly" at the initial rendezvous burn at Eros, the camera also had some significant fogging due to vented hydrazine or combustion product contamination, that didn't help, either.

The infrared spectrometer failed relatively early in the orbital period and wasn't able to clearly separate fresh and non-fresh exposures of surface material, and the X-ray and Gamma ray instruments simply weren't sensative enough and didn't have enough dwell-time and spatial resolution to resolve fresh from non-fresh material from very low orbital passes. In fact, the only really good gamma data for some analysis from the mission was the data taken after landing.

The mission was a major success, but still, it just didn't really do the job it was supposed to be able to do for the mission to be fully justified.

Jeffrey Bell (the one at the U. of Hawaii) certainly thinks NEAR fizzled at that task. Indeed he thinks that nothing short of an asteroid sample return can setttle the issue; he takes a dim view of remote compositional observations in general.

As for Discovery: NASA has now announced that the cost cap for the next Discovery selection has been hiked all the way up to $450 million -- which also means that there are going to be fewer missions. The plan was to release the new Announcement of Opportunity this week -- but there has been a delay: apparently someone has now managed to persuade Congress to launch an investigation of the whole Discovery program, with as-yet uncertain ultimate consequences.

http://www.eso.org/outreach/press-rel/pr-2005/pr-15-05.html

Preparing for the Impact
ESO Telescopes Take Snapshot of Comet 9P/Tempel 1 in Readiness for Major Observation Campaign

http://www.floridatoday.com/apps/pbcs.dll/.../505310327/1006

CAPE CANAVERAL - Deep Impact is on track to smash its impactor into a comet July 4, but its high-resolution camera's focus is still imperfect.

Jun. 9 -- Deep Impact Briefing - NASA TV

10 a.m. PDT

New report on the HRI

http://www.space.com/missionlaunches/05060...act_camera.html

It appears that Deep Impact is suffering from a re-run of the old Hubble optical problem. Ball Aerospace used an optical surface during the camera manufacturing process which changed shape slightly with different temperatures, and the flyby images will need to be deconvoluted to recover detail. The impact vehicle appears to be OK, however.

I think the only response possible is 'D'oh!'.

Tempel-1 pictured with Medium Resolution Imager (MRI) camera:
http://deepimpact.umd.edu/gallery/DI_T1_doy164.html
(quite strange linear artifacts near the comet... ).

A sad question/consideration. The impactor uses a high-precision star tracker, which imply some kind of optical instrument... why they didn't planned to use it (or add a dedicated small camera) to take a "movie" of nucleus approach?
Even using a low resolution and limiting bit rate (let's say, one picture/min) last images should easily reach sub-meter resolution of pre-impact area, a result impossible even with perfectly focused HRI...

It will.

From the Press Kit:

Thanks James, I completely missed it (hope this will not happens to impactor camera! ).

To be precise, the neucleus and coma images will be taken with the Impactor Target Sensor, which peers out forward through a port in the Impactor's copper mass. The star tracker points at right angles to this camera. It has a wider field of view with fewer pixels so that it can determine the orientation of the spacecraft relative to the stars.

The number and size of the images returned to the Fly-by spacecraft is constrained by the limited power available for the S-band communications link and the distance between the spacecraft, which grows to >8000 km at impact. Pictures of the surface would be great, but the science is in the impact, which takes priority.

Impact minus 12 days!

Tank you very much, comga!
I understand that impact is the main objective, but can you kindly give a little bit infos about the Impactor Target Sensor (optics/sensor)...?

When will science observation start?

Deep impact detects comet nucleus
http://www.newsdesk.umd.edu/scitech/releas...?ArticleID=1087

Try
http://deepimpact.umd.edu/tech/instruments.html

which includes the statement

"The MRI telescope is a Cassegrain design with a 12 cm aperture and a 2.1 m focal length. The optics, mounts, and baffle tube are of similar construction to the HRI telescope. The MRI and the Impactor Targeting Sensor are identical other than the filter wheel."

The CCD arrays are the same on all three instruments. They are all on-axis Cassegrain telescopes, with the focal length of the HRI being five times that of the MRI and ITS.

You can also look at the JPL site

http://deepimpact.jpl.nasa.gov/tech/instruments.html

There is a wealth of information on the instruments, and lots of links.

You can see that with a pixel projection of 10 microradians, (10 meters at 1,000,000 meters distance) if it snaps a picture ten seconds out, at a distance of 100 km, the resolution would be one meter. If it gets one five seconds out, its half a meter. The 20 cm resolution mentioned as a limit would require taking the picture at 2 seconds out, from 20km, and sending it to the fly-by spececraft before being vaporized. That assumes that the impactor doesn't get hit with a dust particle, which could cause it to lose stability. The crater would be uneffected, but any images would be smeared.

The Ranger 7-9 moon probes were each transmitting images when they went ZIP-CRUNCH. In each case, a variable portion of a full-frame image <either A or B frame> and one of the 200 line partial scan <P1 through P4> images was "in transmission" at impact. Since the data was analog slow-scan raster, there was no problem making an image of the fragment up to the last millisecond of image.

Are the impactor's data compressed, so that partial frame data will be partially corrupted, or are they raw bit stream, so that every last pixel up to the one "in transmission" at the moment of impact will be recoverable?

It's going to be a bit like NEAR in a way isnt it - image image image wow - didnt expect them this low - image image - crunch

I would imagine there isnt enough grunt or time to compress, it's not like they can re-transmit to get back some lost bits - and compressed data suffers a lot with a single lost bit, so they'll wizz straight back to the fly-by uncompressed I'd imagine - and thus, the last image will almost certainly be partial
Doug

Thanks again, Comga!
About compression, I made a little small calculation: based on Impactor Technology description (http://deepimpact.jpl.nasa.gov/tech/impactor.html), it will transmit at nominal data rate of 64 Kbps, so this translates into a mere 16 KBytes every 2 seconds... a full res image from ITS, however, should be 1 MB uncompressed (assuming 8bit/pixel), so they should strongly compress it before transmission (more than 60:1 ratio!); this would require heavy/fast number crunching but, probably, board computer is not so sophisticated and, in addition, Doug is right about compression side effects.
I tend also to exclude pixel re-bin (subsampling) because this would compromise nominal resolution which is declared to be 20cm @ 20 Km distance. The only possible conclusion is that, at least for very last pictures, only a (central) small portion of image will be transmitted, probably something like 256x256 or even less, considering that shortly before impact the pace of imaging will increase until it reaches a maximum of one picture every 0.7 second...
So, under the best conditions, let's prepare to see only a small portion (50m?) of the comet nucleus with maximum resolution...

Judging from the Giotto dust impact experience (it *really* needed the Whipple bumpers!) I'd expect the smart bullet to get some pretty hefty whacks, so there's every chance it's tumbling whern it hits. Assuming that the transmitter antenna geometry isn't critical then that could actually give us an interesting spread of images - or none at all!