[JSR] Jonathan's Space Report, No. 649
Jonathan McDowell
jcm at planet4589.org
Wed Oct 26 12:24:09 EDT 2011
Jonathan's Space Report
No. 649 2011 Oct 25 Somerville, MA, USA
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ROSAT reentry
--------------
ROSAT reentered between 0143 and 0157 UTC on Oct 23 according
to data from USSTRATCOM. Including the final orbital data released later
on Oct 23, the uncertainty range covers the Indian Ocean, the Andaman Sea,
Myanmar, Laos and China. There have been no confirmed sightings of the reentry.
Germany's ROSAT satellite (Rongtensatellit) was the third X-ray mission to
image the extrasolar X-ray sky, following Einstein and Exosat. It made
the first imaging all-sky survey; its telescope observed at lower energy
(`softer', longer wavelengths) than Chandra and XMM and so it was
particularly sensitive to the (relatively) lower temperature nearby
interstellar gas. It discovered X-rays from comets interacting with the
solar wind, cataloged high redshift X-ray galaxy clusters and measured
their dark matter, and identified many new quasars.
The ROSAT X-ray telescope (XRT) and its main cameras, the two PSPC
(Position Sensitive Proportional Counter), PSPC-B and PSPC-C, were
developed under the leadership of the Max-Planck-Institut fur
extraterrestriche Physik (MPE) in Garching bei Munchen. The XRT could
also image onto the HRI microchannel-plate camera developed at
Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts,
while Leicester University's EUV Wide Field Camera was a separate
telescope bolted on the side. The spacecraft was controlled from GSOC
(Oberpfaffenhofen/Weilheim) while US participation included the GSFC
guest observer facility and the SAO science data center.
Launched to a 564 x 584 km x 53.0 deg orbit on 1990 Jun 1, ROSAT was in
a 244 x 250 km orbit as of 2011 Oct 10. The PSPC-C carried out the X-ray
all-sky survey between launch and an accident on 1991 Jan 25, when
PSPC-C was destroyed by accidentally observing the Sun during a system
failure. The PSPC-B took over for the pointed-target phase of science
observations, together with the HRI. PSPC-B was retired in 1994 when its gas
supply was near empty and the HRI was the sole instrument between 1994
and 1998. It had higher spatial resolution than PSPC, but didn't
have the energy resolution that enabled PSPC to distinguish different
X-ray spectra.
ROSAT was damaged after an attitude control problem on 1998 Sep 20. When
performing a slew (change of pointing direction), the reaction wheels
that manage the satellite's angular momentum were unable to keep up and
the satellite's aperture followed the wrong track across the sky,
crossing the Sun and resulting in destruction of the ultraviolet filter
on the HRI. This makes it the only astronomy satellite I know of
to have attempted suicide-by-solar-observing on two separate occasions.
The science program was declared abandoned on 1998 Oct 28; however, the
last dribble of PSPC-B detector gas was used for test observations between
1998 Dec 6 and 18. The spacecraft was abandoned on 1999 Feb 12.
Debunking a tall tale
---------------------
The Wikipedia page for ROSAT includes a story which says that a 1999 NASA
internal report raised the possibility that ROSAT's demise was instead
due to some kind of hacker attack. In 1998 there was an intrusion of
some kind into the NASA-Goddard network which contained the source code
for the flight software of several NASA satellites. According to the
author of the report, `exploitation of the comm link could not be ruled
out' - presumably the fear was that someone could use knowledge of the
code to use their own ground station to command a satellite, or separately
hack in to the NASA ground station.
But despite the report, this just can't have happened with ROSAT. As
I've confirmed with Rob Petre who ran the Goddard part of ROSAT, all we had
were copies of the downlinked science data. All commanding, scheduling
and operations of ROSAT were done from Germany at GSOC - NASA had no
role in the spacecraft commanding.
ROSAT was an elderly satellite in 1999, its main mission long completed.
Its failure is not surprising and is fairly well understood. I've talked
with several scientists involved in senior roles with the ROSAT mission
and the unanimous opinion is that the story is ludicrous.
To summarize: Someone did gain inappropriate access to an internal NASA
network in 1998. As far as I know there's no evidence that restricted
satellite flight software was actually downloaded. But whatever
happened, it was definitely nothing to do with the malfunction of ROSAT
that damaged the HRI.
PSLV launch
-----------
India launched PSLV-C18, a PSLV-CA core-alone variant, from Sriharikota
on Oct 12. The main payload of PSLV-C18 is the Megha-Tropiques
satellite, a joint Indian-French remote sensing satellite with a mass of
around 1000 kg and based on the IRS bus. It carries the MADRAS microwave
imager, the Saphir water vapor profile instrument, and the ScaRaB
radiation budget sanner.
Also carried were three small satellites: SRMSAT, from SRM University in
Chennai, is a 10 kg satellite for greenhouse gas monitoring. Jugnu, from
the Indian Inst. of Technology in Kanpur is a 3U cubesat-class
technology satellite. VesselSat is a 29 kg small satellite built by
OHB LuxSpace of Luxembourg to provide AIS (ship tracking) services for
Orbcomm.
The five objects are in orbits with an apogee of 867 km and perigees
ranging from 780 to 850 km; the low perigee object is probably the rocket
stage.
GALILEO
-------
Europe's first two Galileo navigation satellites were launched on Oct 21.
This was also the first Soyuz launch from the Centre Spatial Guyanais.
The new Ensemble de Lancement Soyuz pad is a copy of the pads at Baykonur.
The Soyuz ST-B launch vehicle is the Soyuz-2-1B variant; an uprated Fregat-MT
upper stage was used for the first time.
The two satellites have been given the nicknames Thijs and Natalia
after competition winners Thijs Paerlman (b. 2000) and Natalia Nikolaeva
(b. 2002).
Two earlier test satellites, GIOVE A and GIOVE B, were launched in
2005 and 2008.
ViaSat-1
--------
ViaSat-1 is a Ka-band broadband data satellite launched by a Proton
from Baykonur. It will provide capacity over North
America. The heavy (6740 kg launch) Loral-1300 satellite
is owned by ViaSat, a California-based company; the payload includes
9 Canadian spot beams owned by Telesat in addition to the 63
US beams owned by ViaSat. As of Oct 25, ViaSat-1 was in a
12291 x 35781 km x 9.5 deg orbit on its way to a geostationary
location at 115W.
Suborbital flights
-------------------
The PICTURE payload, NASA 36.225UG, was launched from White Sands in
an attempt to image an exoplanet. The CHAMPS flights, one nighttime and
one daytime, were launched from Andoya to study meteoritic dust
in the upper atmosphere.
Table of Recent (orbital) Launches
----------------------------------
Date UT Name Launch Vehicle Site Mission INTL.
DES.
Sep 10 1308 GRAIL-A ) Delta 7920H Canaveral SLC17B Lunar 46A
GRAIL-B ) Lunar 46B
Sep 18 1633 Zhongxing 1A Chang Zheng 3B(E?) Xichang Comms 47A
Sep 20 2247 Kosmos-2473 Proton-M/Briz-M Baykonur Comms 48A
Sep 21 2138 Arabsat 5C ) Ariane 5ECA Kourou ELA3 Comms 49A
SES 2 ) Comms 49B
Sep 23 0436 IGS O-4 H-2A 202 Tanegashima Imaging 50A
Sep 24 2018 Atlantic Bird 7 Zenit-3SL SL Odyssey, Pacific Comms 51A?
Sep 27 1549 Tacsat-4 Minotaur 4+ Kodiak Comms 52A
Sep 29 1316 Tiangong-1 Chang Zheng 2FT1 Jiuquan Module 53A
Sep 29 1832 Quetzsat-1 Proton-M/Briz-M Baykonur LC200/39 Comms 54A
Oct 2 2015 Glonass-M No. 42 Soyuz-2-1B Plesetsk Navsat 55A
Oct 5 2100 Intelsat IS-18 Zenit-3SLB Baykonur LC45 Comms 56A
Oct 7 0821 Eutelsat W3C Chang Zheng 3B(E) Xichang Comms 57A
Oct 12 0531 Megha-Tropiques ) PSLV-CA Sriharikota EarthObs 58A
SRMSat ) Tech 58
VesselSat-1 ) Comms/AIS 58
Jugnu ) Tech 58
Oct 19 1848 ViaSat-1 Proton-M/Briz-M Baykonur Comms 59C
Oct 21 1030 Galileo IOV PFM ) Soyuz-2-1B Kourou ELS Navsat 60A
Galileo IOV FM2 ) Navsat 60B
Table of Recent (suborbital) Launches
----------------------------------
Date UT Payload/Flt Name Launch Vehicle Site Mission Apogee/km
Sep 1 1353 ARAV? Terrier Oriole? Kauai Target 150?
Sep 1 1354 Aegis KV SM-3 Block 1B CG-70, Kauai Interceptor 150?
Sep 3 0946 RV Topol' Plesetsk Test 1000?
Sep 26 0320 Prithvi RV Prithvi-2 Chandipur IC3 Test 100?
Sep 29 10 RVs? Layner K-114, Barents Sea R&D 1000?
Sep 30 0400? Agni RV Agni 2 Chandipur IC4 Test 220
Oct 5 0556? FTT-12 Target SRALT? C-17, Kauai Target 100?
Oct 5 0556? FTT-12 Target ? Target SRBM MLP, Kauai Target 100?
Oct 5 0600? THAAD KV THAAD Kauai Intercept 100?
Oct 5 0600? THAAD KV THAAD Kauai Intercept 100?
Oct 8 NASA 36.225UG Black Brant 9 White Sands Astronomy 200?
Oct 11 NASA 41.094UE Terrier Orion Andoya Atm. Sci 130?
Oct 13 NASA 41.093UE Terrier Orion Andoya Atm. Sci 130?
.-------------------------------------------------------------------------.
| Jonathan McDowell | phone : (617) 495-7176 |
| Somerville MA 02143 | inter : planet4589 at gmail |
| USA | jcm at cfa.harvard.edu |
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