A Space & astronomy forum. SpaceBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » SpaceBanter.com forum » Space Science » Space Station
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Jonathan's Space Report, No. 524



 
 
Thread Tools Display Modes
  #1  
Old May 1st 04, 12:49 PM
Jacques van Oene
external usenet poster
 
Posts: n/a
Default Jonathan's Space Report, No. 524

Jonathan's Space Report
No. 524 2004 Apr 23, Somerville, MA
----------------------------------------------------------------------------
---

Space Station Expedition 9 has begun with the Apr 19 launch of Soyuz TMA
spacecraft 11F732 No. 214, designated Soyuz TMA-4. Soyuz TMA-4 is
transport mission ISS 8S and delivers the Expedition 9 crew of
Gennadiy Padalka and Michael Fincke, together with the ESA/Netherlands
DELTA mission crewmember Andre Kuipers, to the Space Station. The Dutch
astronaut will return to Earth with the Expedition 8 crew of Michael
Foale and Aleksandr Kaleri on Soyuz TMA-3, leaving Expedition 9 in
charge of the station. Soyuz TMA-4 docked with the nadir port on Zarya
at 0501 UTC on Apr 21 and the hatches to the ISS were opened at 0630
UTC. Meanwhile, another gyro on the station has shut down and may
require a maintenance spacewalk to replace its failed electronics box.

NASA's Gravity Probe B satellite was finally launched on 2004 Apr 20
after 40 years of development. The 3145 kg spacecraft carries 4
gyroscopes kept at 1.8 Kelvin by a liquid helium dewar, laser
retroreflectors and 2 GPS receivers for orbit determination, a drag
compensation system, and a 14 cm aperture quartz telescope. The
challenging physics experiment, developed by Stanford University
together with Lockheed Martin, will observe the 5th magnitude star IM
Peg for over a year, attempting to measure the tiny shifts in the
gyroscopes' orientation caused by the Lense-Thirring gravitomagnetic
(or `frame-dragging') effect predicted by general relativity. The
frame-dragging caused by the Earth's rotation will make the orbital
plane rotate by 40.9 millarcseconds per year. GP-B's polar orbital
inclination of 90.01 degrees was chosen to minimize the orbital plane
rotation due to the Newtonian effect of the Earth's polar flattening,
which is proportional to the cosine of the inclination. GP-B will also
make an accurate measurement of the well-established gravitostatic
warping of spacetime due to the Earth's mass, which is a much larger
effect of 6.6 arcseconds per year in a perpendicular (in-plane) direction.

One way of thinking about the gravitomagnetic effect is as a kind of
antigravity, in that it decreases the gravitational attraction between
two moving masses. Like electromagnetism, it is always smaller (by
powers of v/c) than the static gravitational attraction. In
electromagnetism, however, the static effect can be (and usually is)
cancelled out by having equal amounts of positive and negative electric
charges, and so the small relativity effect between moving charges that
we call "magnetism" becomes dominant and indeed familiar. Because there
are no negative gravitational charges (even antimatter particles have
positive mass) this never happens with gravity, ensuring that the
antigravity, moving-masses, Lense-Thirring effect is always much less
than the normal positive gravity generated by the same masses, and thus
doesn't do starship inventors any good. [Warning: I am not a real
relativist: there are probably egregious errors in the above
description.]

In Newtonian physics when a satellite orbits a spherical planet the
orbital plane of the satellite `stays put' and the planet `turns
underneath it'. It doesn't matter whether or not the planet is rotating.
The effect of relativistic frame dragging is to change the meaning of
`stays put', rotating the path of a locally freely falling object near
the planet with respect to the distant universe. We think of the gravity
of the rotating planet dragging spacetime around with it. For a
non-polar orbit, it becomes easier to orbit in the direction of rotation
than against it, with the equivalent of Kepler's third law becoming
inclination-dependent - in some sense a prograde orbit has a lower
orbital velocity than a retrograde orbit of the same height, because the
mass pulls it around for free. Around a rotating black hole, this effect
becomes huge, and the last stable prograde orbit is much closer in than
the last stable retrograde orbit.

The Delta 7920 rocket entered a 167 x 652 km transfer orbit and then
fired again to put GP-B in a 641 x 645 km x 90.01 deg orbit. The second
stage then separated and two further burns put it in a 182 x 631 km x
94.56 deg orbit to ensure that it would not recontact GP-B and that it
will reenter rapidly.

China launched two small satellites from its low-latitude Xichang launch
site on Apr 18 into a 599 x 615 km x 97.7 deg polar orbit. This was the
first polar launch from Xichang; previous Chinese sun-synchronous
missions were from Taiyuan. Shiyan 1 ('Experiment') is a 204 kg
microsatellite developed by the Harbin Institute of Technology, with a
stereo imager to carry out land resource mapping. Naxing 1 (a
contraction of Nami Weixing 'Nanosatellite') is an experimental vehicle
with mass under 25 kg to test small satellite technology and was
developed by Tsinghua University in Beijing. Pictures of the launch show
a fairing similar to the one used for the CZ-2C/SD but given the low
total mass of the payloads I'm assuming that no upper stage was used and
that the CZ-2C second stage entered orbit; payload deployment was 12 min
after launch. Four objects have been cataloged: two objects in the 599 x
615 km orbit are probably Shiyan-1 and Naxing 1, while a third object in
a 543 x 619 km orbit is believed by visual observers to be the second
stage. Seven debris objects have been cataloged, of which four are
probably the second stage separation motor covers. 2004-14D is in a much
lower perigee orbit of 350 x 606 km x 97 deg and may have separated
prior to second stage vernier cutoff. (It's also possible that 14D is
the second stage, and 14C is a third stage insertion motor; at the
moment I think this is less likely.)

A Lockheed Martin Atlas IIAS, serial AC-163, was launched on Apr 16 into
a 150 x 396 km parking orbit and then restarted to reach a 167 x 122343
km x 26.3 deg highly elliptical orbit. It delivered to orbit the
Superbird 6 satellite, a Boeing BSS-601 model which will provide Ka and
Ku band communications for Japan's Space Communications Corp. with the
operational name of Superbird A2. The high apogee orbit will allow
Superbird 6 to lower its inclination to equatorial with a minimum usage
of fuel, and only then lower its orbital height to the 35780 km
geostationary altitude. Once again, Space Command took a long time to
issue orbital data; the first elset was issued on Apr 21, giving an
orbit of 1137 x 120678 km x 25.48 deg following the initial apogee
burns.

The Briz from the Eutelsat launch and the Blok DM from the Kosmos-2406
launch have still not been tracked; I gather that Space Command has
fewer deep space sensors than it used to, due to budget cuts. Given the
increasing importance of deep space `situational awareness', I assume
this suprising lack of US capability will be remedied fairly soon.
Kosmos-2406 is now being tracked in geostationary orbit at 85.0E.
Eutelsat W3A is on station at 1.8E.

The Scaled Composites rocket-powered Spaceship One made its second
powered flight on Apr 8 to an altitude of 32 km. This altitude has
previously been exceeded on a piloted flight by the Ross-Prather 1961
balloon flight, one Ye-66 (modified MiG-21) and two Ye-266 (modified
MiG-25) jet flights, several NF-104A Starfighter flights, one X-2
flight, many flights of the X-15 rocketplanes, and of course all
spaceflights. Once the Scaled team reaches 37 km it will be closer to
record territory: the highest non-X-15 piloted flights I am aware of
were Aleksandr Fedotov's 37.7 km MiG E-266M flight on 1977 Aug 31 and
Iven Kincheloe's 38.5 km X-2 flight on 1956 Sep 7. There were 70 flights
of the X-15 higher than that.

Table of Recent Launches
-----------------------

Date UT Name Launch Vehicle Site Mission
INTL.

DES.
Mar 2 0717 Rosetta Ariane 5G+ Kourou ELA3 Comet probe
06A
Mar 13 0540 MBSAT Atlas IIIA Canaveral SLC36B Comms
07A
Mar 15 2306 Eutelsat W3A Proton-M/Briz-M Baykonur PL81 Comms
08A
Mar 20 1753 Navstar SVN 59 Delta 7925 Canaveral SLC17B Navigation
09A
Mar 27 0330 Kosmos-2406 Proton-K/DM-2? Baykonur PL81 Comms
10A
Apr 16 0045 Superbird 6 Atlas IIAS Canaveral SLC36A Comms
11A
Apr 18 1559 Shiyan 1 ) CZ-2C Xichang Imaging
12A
Naxing 1 ) Tech
12
Apr 19 0319 Soyuz TMA-4 Soyuz-FG Baykonur LC1 Spaceship
13A
Apr 20 1657 Gravity Probe B Delta 7920 Vandenberg SLC2W Science
14A

..-------------------------------------------------------------------------.
| Jonathan McDowell | phone : (617) 495-7176 |
| Somerville MA 02143 | inter : |
| USA |
|
|
|
| JSR:
http://www.planet4589.org/jsr.html


--
---------------------------

Jacques :-)

www.spacepatches.info



Ads
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
National Space Policy: NSDD-42 (issued on July 4th, 1982) Stuf4 Space Shuttle 150 July 28th 04 07:30 AM
Unofficial Space Shuttle Launch Guide Steven S. Pietrobon Space Shuttle 0 April 2nd 04 12:01 AM
Clueless pundits (was High-flight rate Medium vs. New Heavy lift launchers) Rand Simberg Space Science Misc 18 February 14th 04 03:28 AM
International Space Station Science - One of NASA's rising stars Jacques van Oene Space Station 0 December 27th 03 01:32 PM
Unofficial Space Shuttle Launch Guide Steven S. Pietrobon Space Shuttle 0 September 12th 03 01:37 AM


All times are GMT +1. The time now is 09:31 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright 2004-2022 SpaceBanter.com.
The comments are property of their posters.