David Morrison <>

    Benny J Peiser <>

    David Morrison <>

    Ed Grondine <>

    Alan W. Harris <>

    Wolfgang Kokott <>


From: David Morrison <>


I am surprised at your inflamatory interpretation of Clark's comments.
I was actually rather shocked when you wrote "Does this mean that the
international astronomical community in general and NEO researchers in
particular will be under the control and dictate of a governmental agency
(i.e. NASA) which is accountable to and controlled only by the US
Government? If the answer to this question is Yes, do you seriously
believe that professional and amateur astronomers from Russia, China
and other independent nations will continue to provide their scientific
information to an agency of the American Government?" Surely you know
better. The role of the US federal government (NASA) in this case is as
a supplier of grant funds for research in response to requests
(proposals) for such funding from an investigator (PI) at an
educational institution (Brian Marsden at the Harvard-Smithsonian
Center for Astrophysics). Any grant has certain strings attached; this
is true of all the research efforts funded by NASA in response to
proposals. If Marsden doesn't want these funds he doesn't need to
accept them and he should not write proposals asking for them.  The
same is true for any of the observers supported by NASA, which is most
of those teams now discovering NEOs, such as Gehrels/McMillan/Scotti,
Bowell/Shoemaker, Helin/Pravdo, Larson, Tholen, etc. It is as simple as
that. There is no issue of a government agency controlling the IAU or
any other sinister agenda as you seem to imply.

David Morrison


From: Benny J Peiser <>

Dear David

Hardly 12 hours had passed after my request for clarification, that I
received your latest NEO News. I understand from your mailing that NASA
is now proposing to stamp its authority (and political control) on the
research findings and running of the Minot Planet Centre. As you are
well aware, the MPC has been the focal point and clearing house for
the  i n t e r n a t i o n a l  astronomical community, particularly
for NEO searches.

Now, I understand that you are playing down the consequences which
would take effect if NASA's proposals would be implemented. But if
everything is so harmless, as you suggest, why did Clark Chapman
explicitly stress the detrimental outcome of NASA's overall control:

"International colleagues are jutifiably concerned about NASA
being the final arbiter in these matters."

Why do you think scientists from around the world are concerned when a
governmental agency, without any consultations and against the
explicit wish of many in the field, tries to dictate the terms for how
to conduct international scientific research?

With best wishes,



From: David Morrison <>

NEO News (4/7/98)

NASA Proposed Interim Roles and Responsibilities for NASA-funded
researchers on Reporting Potentially Hazardous Objects (PHOs)1
April 1998

1.  No hazard or threat prediction statements will be released without
verification and consensus.

2.  Astrometric data on Near-Earth Objects (NEOs) or suspected NEOs
received by the Minor Planets Center (MPC) of the International
Astronomical Union at the Harvard-Smithsonian Center for Astrophysics will
be made available to the scientific community, generally within 24 hours of

3.  Should a member of the NEO search community2 note a future, possibly
threatening, close approach to the Earth, the other members of the NEO
search community will be notified so that calculations can be checked and
archival files can be searched for prediscovery observations. The
response will be coordinated by a point of contact to be designated by
the NASA Office of Space Science (OSS), and the search community will
make an effort to reach consensus as to the nature of the threat within
48 hours of being informed.

4.  The NASA OSS will be informed at least 24 hours in advance of any
public report of a PHO.

5.  NASA, in coordination with appropriate national and international
organizations, will sponsor a study of how best to communicate NEO issues
to the public.  This study will include an international workshop to
develop detailed recommendations concerning procedures, roles, and
responsibilities regarding observations, orbit calculations, and
communications with the public and policy-making officials.

1 These interim guidelines represent an agreement among
          NASA-supported NEO searchers and dynamicists.
2 The NEO search community includes all major NEO searchers,
          dynamicists, and data archivists.


From: Ed Grondine <>

Benny -

      I think that you are getting over alarmed, in part because you have
never before seen up-close a turf war conducted within the U.S.

     To tell about the origin of Smithsonian operations back in
1957/1958 (Moonwatch/Moondust) is way beyond the scope of this list; to
recount the turf battles between NASA and the Air Force over 4 decades
would easily make for an 8 part television series, though I doubt anyone
would watch.  So let's concentrate on the present.

      Earlier proposals for planetary defense were seen by many left
politicians in the United States as simply an excuse by the right for
continuing work on the Starwars progrram (SDI), and dismissed as such.
While it is now becoming clear that the impact threat is very real, and
that it has to be addressed, not too surprisingly President Clinton has
decided to appoint NASA as lead agency to deal with it, despite the fact
that NASA has no experience with the kind of nuclear charges that are
going to be necessary to stop a large impactor.  While Clinton has
appointed NASA lead agency, no one at NASA has yet figured out that the
strategic (policy) plan for NASA is going to have to be fundamentally
changed to reflect the seriousness of the threat and their new
responsibilities.  Instead they engage in CYA activities (CYA is a
Washington acronym for "Cover Your Ass"). 

       While BMDO has been watching small ones come down for years and
is very worried about what it has seen and is seeing, the Air Force
leadership, for their part, is simply saluting the President and saying
that it is NASA's responsibility.  In the mean time, from the looks of
things (and this is simply completely undocumented opinion, of course)
the right leadership in the House has not chosen to debate the issue,
but is depending upon a smear campaign constructed on documents stolen
by a secretary from the President's lawyer's office to bring him down.

     As I said before, you're simply getting overly alarmed, so enough
about the political situation.  That detecting the next impactor and
stopping it before it hits is a task that is going to require resources
beyond those of the United States, and will have to be an international
effort, due to the size of the task, is a concept that neither the left
nor the right leadership has even a glimmer of yet. In any case, do not
expect any serious action until this summer's movies, and serious action
may follow only if the threat is not dismissed as simply another case of
science fiction on the level of Star Trek or Starwars (the movie).

     In the meantime, if NASA continues to step on the Smithsonian's and
IAU's toes, I suggest the following:  Next time a list member is asked
one of those difficult questions by a journalist, like "Surely someone
must have a plan to (detect potential impactors, stop them, etc.)?",
simply reply, "Yes, why certainly, NASA has a plan all for exactly that. 
Just ask (name of boorish individual), he can tell you all about it."

                                         Best wishes -

From: Alan W. Harris <>

Dear Benny,

Here is my response to the list of questions you asked Chapman.  You may
publish my responses if you see fit.



>From: Benny J Peiser <>
>Dear Clark
>I would like to ask you to clarify some of the points you have raised
>in your statement:
>1) On the basis of the observational data available on March 11th,
>Brian Marsden calculated that “the object will pass only 0.00031 AU
>from the earth on 2028 Oct. 23.73 UT!” On the basis of the same data,
>four independent NEO researchers confirmed Brian Marsden’s prediction
>that the asteroid would pass within 0.002 AU. D.K. Yeomans & P. Chodas
>calculated a miss distance of 0.00058 AU, K. Muinonen found the miss
>distance to be around 0.00033 AU and E. Bowell derived a miss distance
>of 0.00023 AU (see IAUC 6839, 12 March 1998).

Let me illustrate this with an analogy.  The "error ellipse" of 1997 XF11
was not an "ellipse" in the normal concept of "egg-shaped."  It was (based
on the 1997-8 data alone) only 2550 km wide, but 2.8 million km long.  Thus
a "picture" of this ellipse drawn on a scale sufficient to show the Earth
as more than a tiny dot looks more like a pair of railroad tracks than an
ellipse.  The Erath is offset from this ellipse by about 10-20 times the
width of the "tracks."  Like a train, the location of the close approach in
2028 is constrained to lie within those "tracks."  If you are not on the
tracks, you are in no danger of being hit.  As for understanding the
various miss distances of 0.00023, 0.00031, 0.00033, 0.00058 AU, we can
continue the analogy.  Suppose you are standing 100 feet off to the side of
the train tracks (10-20 times the rail separation), and you have noted from
a week's observations that a train passes by at 10:30 every day, plus or
minus 1 minute.  At 60 miles an hour, that is +/-1 mile.  Tomorrow, as you
stand there, how far away will the train be at precisely 10:30?  If it is
exactly on time, thus sitting as close to you as possible, the answer is
100 feet.  But if the train is early or late by one minute, it will be
fully 1 mile away.  Even though 1 mile is a lot more than 100 feet, there
is absolutely no chance of being hit by the train, unless the train jumps
the tracks -- read "systematic errors", "non-gravitational forces",
"perturbations by other asteroids", or whatever.  In two dimensions, all of
the predicted miss distances which you mention (with the possible exception
of Marsden's, where we don't know the details of his solution in two
dimensions) lie "on the tracks."  the differences arise from tiny
differences in integrators, treatment of roundoff errors, etc., which may
shift the computed solution point by little bits along the path, but not by
signidicant amounts.  Continuing even further with the analogy, it is as if
the various investigators had computed that the train passes directly in
front at 10:30:03, 10:30:05, and 10:30:08 each day (always +/-1 minute).
Each would calculate a substantially different distance to the train at
precisely 10:30:00, but all would agree that wherever the train is, it will
be on the tracks.

Well, all analogies have their limitations, and this one does too.  You may
say, "well, as long as you stand there for a couple minutes, you can be
sure the train will pass within 100 feet, it's only a question of when.
This is where the analogy fails.  In fact, the "ellipse" is just a
projection of a three-dimensional error envelope (not even exactly an
ellipse) onto a two-dimensional plane, called the "target plane."  The
asteroid is actually moving perpendicular to this plane as it passes close
to the Earth.  The long axis of the ellipse is indeed almost entirely due
to "when" the asteroid comes by, for the simple reason that in projecting
forward 30 years from a 1/4 year baseline of measurements, the biggest
uncertainty is where on the path the object will be, not where the path is.
One can state (although it hasn't been done in the solutions I have seen)
that if 1997 XF11 is, e.g. one minute early of the nominal prediction it
will pass such-and-such distance to the right or left along the ellipse
from the nominal prediction, and if one minute late, it will pass a similar
distance in the opposite direction along the ellipse.  A crude patch-up of
the analogy is to imagine that you are driving your car on a road with an
overpass of the train tracks, so you are only instantaneously close to the
tracks, and then ask how close the train will be as you pass over at 10:30

>Let's presume that all we had on March 11th were the orbital arc after
>88 days of observation and the above calculations by five of the
>world's leading NEO researchers, (i.e. without the addtional data
>provided by Eleanor Helin's films from the 1990 observations). Do
>you believe that on the basis of this knowledge any responsible NEO
>expert would have publicly declared that "XF11 is NOT hazardous"?

On the basis of this knowledge alone, all five of "the world's leading NEO
researchers" agreed that we were standing about 100 feet off to the side of
the tracks, to use the above analogy, that is, more than 10 "sigmas"
outside of the error envelope.  On the basis of this knowledge, I believe
any NEO expert would be irresponsible to declare anything other than that
"XF11 is NOT hazardous."

>2) Let us further assume that Brian Marsden had received the above
>quoted calculations by his outside colleagues PRIOR to the release of
>IAUC 6839. Do you believe that he should have informed the public about
>these calculations of passage (ranging between 0.00023 and 0.00058 AU)
>which, due to their confirmation of an extremly close approach, would
>have necessarily included “a worriesome prediction”?

This is a non sequitor ("would have necessarily included 'a worriesome
prediction'") in view of my reply to your point 1.  If he had been advised
in advance of the 2-dimensional results, as he was within a few hours after
the data were independently analyzed, it would have been unconscionable to
issue a warning without at least pausing to evaluate and understand the
"peer review" received.  The one-word answer to your question is, "no".

>3) Brian Marsden has suggested to “make available, generally on a daily
>basis, all new observations of unnumbered NEOs.” Could you clarify what
>other data you wish to be made public and why?

He should make available ALL data immediately, and should make publicly
available the entire set of all past data, including "one night stands",
which he treats as his own private trove of data for linking past
observations to newly discovered objects like 1997 XF11.  These data are
not his and should be publicly accessible.  He is just the caretaker.  His
policies are like the librarian who insists on reading each book before it
can be placed on the shelf for the public.  This causes unnecessary and
undesirable delay. It is also censorship.

>4) Let us finally assume we could turn back the clock to March 11th.
>All we have to our disposal is the data after 88 days of observation of
>1997 XF11. According to the calculations of one team of experts (say
>IAU), the future approach of the asteroid is so uncomfortably close
>that a collision in 30 years cannot be ruled out entirely. However,
>another group of  experts (say JPL/NASA) believes that their
>calculations are more reliable and thus believe that they can rule out
>collision in 30 years time. What is worse, even after another six
>months, the two groups cannot agree about their conflicting
>calculations. Should such a case ever occur in the future, do you
>believe that the first group of scientists should be allowed to
>release their “worriesome prediction” or should they be prevented
>from going public by an agency of the American Government?

By all means, after a peer review, if scientists cannot agree, the default
is "publish."  I would have to add, though, that any reasonable editor
would probably decline to publish a paper if 5 expert reviewers unanimously
agreed that the result was wrong, even if the original author refused to
accept that evaluation.

>(5) You state that "MPC will have to live with NASA's requirements."
>and that NASA will be "the final arbiter in these matters." Does this
>mean that the international astronomical community in general and NEO
>researchers in particular will be under the control and dictate of
>a governmental agency (i.e. NASA) which is accountable to and
>controlled only by the US Government? If the answer to this
>question is Yes, do you seriously believe that professional and amateur
>astronomers from Russia, China and other independent nations will
>continue to provide their scientific information to an agency of the
>American Government?

I believe David Morrison has adequately addressed this point.  I concur
with his view.

In answering the above questions, I have the feeling that you formulated
the questions that follow based on a premonition of what the answer to the
first one would be.  In dealing with this entire affair, I have the
impression that many others have similarly passed on to the follow-up
questions without fully contemplating and understanding the answer to the
first, fundamental question, which you rightly ask first.  I urge you and
all those on your list to ponder carefully this very first question and my
answer to it, confirm it with the experts in the field, or refute it if you
can. The questions which legitimately follow depend fundamentally on
this first point. If we can't agree on this point, then we really don't
have a basis for further discussion.

With best regards,

Alan Harris (from JPL)


From: Wolfgang Kokott <>

Benny J Peiser wrote:


> I have decided to circulate the following 'addendum' from Clark
> Chapman’s up-dated “Statement about the 1997 XF11 Affair” because it
> might have far-reaching consequences for the future of international
> co-operation in matters of NEO research if ever implemented. I have
> also added my request for clarification in the hope that Clark will be
> happy to address these important issues openly..

> Benny J Peiser
> -----------------------
I think everybody in the astronomical community ought to agree with
your statement.-

I recall some human interest interview -- some time in the '70s --
when Sky and Telescope asked Brian Marsden, ''The Man in the Hot
Seat'', about his position on publishing data on p.h.objects.
Answer: Business as usual, IAUC -- everybody who understands what
delta < 0.001 a.u. means would be entitled to the information. How the
colleagues deal with the hot news will be their responsibility.
So he did, and it's theirs .....
Wolfgang Kokott


CCCMENU CCC for 1998