GRAIL-A and -B Are In Lunar Orbit

1. The money for this should have been spent on COTS-D,Dragon.Like my Avatar?Just think though,6 crewed vehicles now.I would rather Have had one and saved 3 years.That is what SpaceX was saying 3 years ago,3 years for Dragon crew.
   .With the extra 300 million they would have been close.Not fair?They were the only ones to bid.Is it illegal to accept only one bid.?No backup?Orion would have been backup.I looked up Avatar.It does not have to be a person.Yes,I know,I am repeating myself.I have some disagreements with NASA.

2. Excellent !!!

   Now, hopefully, we can put this buffoonery about velcroing an astronaut to an asteroid behind us and focus on what makes the sense: establishing a permanent man presence on the MOON.

   —John

   1. Can’t wait for the results.  Depending on the resolution, would it not be beyond belief if a couple of VERY big Ni/Fe impactors that are buried were found?

      1. Besides the Mass-cons already found?NASA has been doing gravity mapping of the Moon since the first orbiter,50 years ago.They use the same method as GRAIL.They measure the change in signal as the satellite changes speed.GRAIL will only repeat what has been done using a different method.It will do the whole Moon,but there has been polar orbiters before.Don’t know how they measured the backside,but they say no Mass-cons there.NASA knows everything about the Moon.Remember that the Moon rings like a bell?So they know what the core is.This is from the seismology instruments,when they crashed space craft into the Moon.The only thing new with GRAIL is the 2 spacecraft.An engineering exercise. Is it a good idea to do the same thing over and over?

         1. NASA just found out there was H2O there recently.  Saying they know everything about the moon is, to put it nicely, incorrect.

         2. To claim “NASA knows everything about the Moon” is sheer ignorance!

            1. Who claimed that? Just wondering about your quotes.

               Speaking of sheer ignorance …

               With regard to water on the Moon, it was understood theoretically fifty years ago that there was very likely a lot of water in lunar polar craters, and some good observational evidence from Clementine that it was actually there. It was nice to finally detect it, but it wasn’t a huge surprise.

               To add to Dennis’ answer, the gravity resolution of GRAIL is about 30 km. That’s VASTLY finer than what we have now, which is mostly from Lunar Prospector. If you want to find your pile of gold bricks, that’s how you’re going to do it!

               I think there are some folks who believe that what we don’t know about other things in space are more important than what we don’t know about the Moon, but that’s a matter of perspective.

         3. Saturn 13

            You are incorrect and I am saying this as the former PI on NASA’s previous effort to do this type of mission in 1992 called Lunar Resource Mapper.

            The Apollo data and the Lunar Prospector data and the data from all the other satellites that have done this used ranging transponders to do the gravity mapping.  In order to do this at maximum resolution you need two things.  One is to get close to the Moon, which they are doing, and the second is that you need an ultrastable oscillator of sufficient accuracy as to be able to determine very small changes in acceleration caused by the Mascons.

            When we were doing the LRM gravity subsatellite we used a GPS Rubidium Ultrastable Oscillator with a 1 x 10-12 RSS frequency stability.  This is what we could get in 1992.  Today what GRAIL is using is probably 1-2 orders of magnitude better.  This allows extremely precise determination of relative accelerations between the two birds, as well as extremely good determination of the range between each of the birds and the Earth.  

            NONE of the previous missions did ANY worthwhile gravity mapping on the far side, at least since Apollo and that map was of poor quality compared to what GRAIL will do.

            The GRAIL mission will provide an incredibly good data set on the “lumpiness” of the Lunar Gravity field and with what we already know, there is some good likelyhood that this will reveal large buried impactors or at least a very good knowledge of the gravity field, the size of the lunar core, if it is iron, and many other revelations.  It may also prove whether or not Charlie Byrne’s near side megabasin theory is correct.

3. Lunar Orbiter-(NASA) The instrumentation for this experiment included a power source, an
   omnidirectional antenna, and a transponder to obtain information for
   determining the gravitational field and physical properties of the moon.
   High-frequency radio signals were received by the spacecraft from earth
   tracking stations and retransmitted to the stations to provide doppler
   frequency measurements (range rate) and propagation times (range). The
   telemetry data were processed in real time on an IBM 7044 computer in
   conjunction with an IBM 7094 computer. They were then displayed on
   100-wpm teletype machines, x-y plotters, and bulk printers for analysis.
   Data coverage was continuous while the spacecraft was visible from
   earth. Information was acquired during the cislunar, the first, second,
   and third ellipses, and the extended mission (from end of photographic
   mission to lunar impact) phases. Doppler, ranging, hour angle points,
   and declination angle points data were accumulated during tracking. The
   quality of recorded data ranged from good to excellent.
    I was right.I thought it was Doppler.They must have got some real close,good data on that last few passes before impact.GRAIL says 100x better front,1000x back.A person there at Marshall used old seismic data and found the core is liquid,last year.Looks like GRAIL will be a confirmer not a finder.Will a use be found for this info,like the way Algebra turned out?Or just something to add to the database?More just curious science?
    Seven thought it curious that Voyager had 60,000 light years to go,but stopped to map every nebula,even though it was just like the last one.

   1. Saturn

      As the technical lead on the Lunar Orbiter Image Recovery Project (LOIRP), which is digitally processing the Lunar Orbiter images, we find that there is a lot of improvements that can be made in our data today by reprocessing the old information.  

      The PI for that project was Dr. William Sjogren and having known him I can attest that he would have been thrilled at this mission.

      However, I don’t think that you understand what 100X in the front and 1000X on the far side actually means to science.

      1. If that is the true resolution or it makes any difference.The far side will be interesting.From the angles from Earth and the Moon wobbles,they must have got a lot of the far side.Sorry for the doubt.It would seem to me that Doppler and maybe an Atomic Clock would be just as good.I am sure this is better though.Thanks for your service to NASA and the USA and science.I followed all those projects.Forgot most of it.I do not remember anything about finding the liquid core.Looks like writers would have done a search on the Moons core,before saying GRAIL would find all the answers.Finding the core is molten is Nobel prize material.Who gets to keep the money NASA or the employee?

         1. From the angles from Earth and the Moon wobbles,they must have got a lot of the far side.Sorry for the doubt.It would seem to me that Doppler and maybe an Atomic Clock would be just as good.

            No, you only get 59% of the Moon from the wobbles AND the previous gravity measuring missions were at least two orders of magnitude worse resolution.

            Doppler is only as good as the time stability of the clock that generates the signal and to get the kind of resolution that GRAIL is going to get takes a much more stable clock.

4. Hallie: That was jski quoting I.An exaggeration.I will try to be more Data or Vulcan.

Comments are closed.