TEST 2
Jonathan's Space Report
No. 506 draft                                       2003 Aug 1, Cambridge, MA
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Shuttle and Station
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The Expedition 7 crew, Yuriy Malenchenko and Edward Lu, remain on board
the Space Station. 

Errata
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I should know better than to do physics in public. A couple of
readers caught my goof in the foam calculation last issue: using
the equations in the CAIB document, I foolishly did not account
for the fact that for a denser material like ice, the lower
drag acceleration means that the time to travel a fixed
distance d in the orbiter rest frame is a function of the
density. My correspondents assumed constant acceleration a
and derived v^2 = 2ad which leads to a kinetic energy independent
of density. But this isn't right either, since the acceleration
decreases quite quickly as the the particle's velocity approaches
the flow velocity, and if you integrate the velocity equation
derived by the CAIB you get a more complicated formula, but
to first order it is true that the the KE is independent of
density, not inversely proportional as I claimed. In fact,
the KE for the ice impact is about 50 percent larger than
that for the foam. Oh well,
the point remains that foam is counterintuitively not as much
better than ice as you might expect.


Neville Kidger points out that he published the TMA-1 landing time
in the July 2003 issue of Spaceflight. Fair enough Neville, you beat me.



Recent Launches
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Aalborg University has contacted its AAU-Cubesat nanosatellite.
As far as I know, the other Danish cubesat DTUSat is still silent.
A source tells me that the identifications in the Space Command
for some of the 2003-031 objects are still mixed up.



Table of Recent Launches
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Date UT       Name            Launch Vehicle  Site            Mission    INTL.
                                                                          DES.

Jul  8 0318   MER-B Opportunity Delta 7925H     Canaveral SLC17B  Mars probe 32A
Jul 17 2345   Rainbow 1         Atlas V 521     Canaveral SLC41   Comms      33A

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|  Jonathan McDowell                 |  phone : (617) 495-7176            |
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